Change search
Refine search result
12345 101 - 150 of 207
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 101.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Multisportens fysiologi2011In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 20, no 2, p. 50-53Article in journal (Other academic)
    Abstract [sv]

    Hur klarar kroppen flera dygn av tävling med relativt hög intensitet? Multisportare genomför sina lopp, men enligt traditionella fysiologiska förklaringsmodeller borde de ramla ihop av utmattning långt innan målgång. I vårt projekt ser vi hur kroppen och hjärtat istället anpassar sig till ansträngningarna utan några tecken på hjärtmuskelcellsskador.

  • 102.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH.
    Mutation i kalciumkanaler ansvariga för plötslig hjärtdöd.2008In: Idrott & kunskap, ISSN 1652-6961, Vol. 5, no 3, p. 10-Article in journal (Other (popular science, discussion, etc.))
  • 103.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH.
    Mysteriet plötslig hjärtdöd2009In: Idrottens olösta gåtor / [ed] Christian Carlsson, Stockholm: SISU Idrottsböcker , 2009, 1, p. 54-65Chapter in book (Other (popular science, discussion, etc.))
  • 104.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH.
    När hjärtat slutar slå: Plötslig hjärtdöd2009In: Idrott & Kunskap, ISSN 1652-6961, no 4, p. 26-30Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Det är alltid tragiskt och ofta ett mysterium när en till synes helt frisk idrottsutövare faller död ned på planen mitt under pågående match. I den här artikeln ska vi försöka bena ut begreppet ”plötslig hjärtdöd inom idrotten”: Vad är det? Vad beror det på? Och vad kan man göra för att förhindra det? I början av juli hölls en konferens vid Stanford Universitetet i USA där världsledande experter i ämnet var samlade.

  • 105.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Physiology of Adventure Racing: with emphasis on circulatory response and cardiac fatigue2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The overall aims of this thesis were to elucidate the circulatory responses to ultra-endurance exercise (Adventure Racing), and furthermore, to contribute to the clarification of the so called “exercise-induced cardiac fatigue” in relation to said exercise. An Adventure race (AR) varies in duration from six hours to over six days, in which the participants have to navigate through a number of check-points over a pre-set course, using a combination of three or more endurance/outdoor sports, e.g., cycling, running, and kayaking. This thesis is based on the results from four different protocols; 12- and 24-h (n = 8 and 9, respectively) in a controlled setting with fixed exercise intensity, and 53-h and 5-7-day (n = 15 in each) in field setting under race conditions. The subjects in all protocols were experienced adventure racing athletes, competitive at elite level. Study I and II address the circulatory responses and cardiovascular drift, using methods for monitoring heart rate (HR), oxygen uptake (VO2), cardiac output (non-invasive re-breathing) and blood pressure, during ergometer cycling at fixed steady state work rate at periods before, during and after the ultra-endurance exercise. In Study III and IV we examined the possible presence of exercise-induced cardiac fatigue after a 5-7-day AR, from two different perspectives. In Study III analyses were performed with biochemical methods to determine circulating levels of cardiac specific biomarkers (i.e., creatine kinase isoenzyme MB (CK-MB), troponin I, B-type natriuretic peptide (BNP) and N-terminal prohormonal B-type natriuretic peptide (NT-proBNP)). We also made an attempt to relate increases in biomarkers to rated relative performance. In Study IV we used tissue velocity imaging (TVI) (VIVID I, GE VingMed Ultrasound, Norway) to determine whether the high workload (extreme duration) would induce signs of functional cardiac fatigue similar to those that occur in skeletal muscle, i.e., decreased peak systolic velocities. Using conventional echocardiography we also evaluated whether the hearts of experienced ultra-endurance athletes are larger than the normal upper limit. The central circulation changed in several steps in response to ultra-endurance exercise. Compared to initial levels, VO2 was increased at every time-point measured. The increase was attributed to peripheral adaptations, confirmed by a close correlation between change in VO2 and change in arteriovenous oxygen difference. The first step of the circulatory response was typical of normal (early) cardiovascular drift, with increased HR and concomitantly decreased stroke volume (SV) and oxygen pulse (VO2/HR), occurring over the first 4-6 h. The second step, which continued until approximately 12h, included reversed HR-drift, with normalisation of SV and VO2/HR. When exercise continued for 50 h a late cardiovascular drift was noted, characterised by increased VO2/HR, (indicating more efficient energy distribution), decreased peripheral resistance, increased SV, and decreased work of the heart. Since cardiac output was maintained at all-time points we interpret the changes as physiologically appropriate adaptations. Our findings in Study III point towards a distinction between the clinical/pathological and the physiological/exercise-induced release of cardiac biomarkers. The results imply that troponin and CKMB lack relevance in the (healthy) exercise setting, but that BNP, or NT-proBNP adjusted for exercise duration, might be a relevant indicator for impairment of exercise performance. High levels of NTproBNP, up to 2500 ng · l -1 , can be present after ultra-endurance exercise in healthy athletes without any subjective signs or clinical symptoms of heart failure. However, these high levels of NT-proBNP seemed to be associated with decreased relative exercise performance, and might be an indicator of the cardiac fatigue that has previously been described after endurance exercise. Study IV revealed that the sizes of the hearts (left ventricle) of all of our ultra-endurance athletes were within normal limits. The measurements of peak systolic velocities showed (for group average) no signs of cardiac fatigue even after 6 days of continuous exercise. This discrepancy between ours and other studies, involving e.g., marathon or triathlon, might reflect the fact that this type of exercise is performed at relatively low average intensity, suggesting that the intensity, rather than the duration, of exercise is the primary determinant of cardiac fatigue.

  • 106.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Precision health and accuracy of wearable devices.2017Conference paper (Other academic)
  • 107.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Requirements for Soldiers’ Endurance Capacity in Prolonged Continuous Work2014Conference paper (Refereed)
    Abstract [en]

    Physiological factors that influence soldier’s ability to sustain performance level in prolonged continuous work are such as A) initial physical level; B) ability to carry; and C) ability to sustain performance level over prolonged periods of time.

    A) General fitness level is obviously crucial, such as strength and aerobic capacity, but so is also being completely healthy when the effort initiates. We have presented an immunological profile that might be useful to determine which soldiers that will underperform. Before a 6-day military training course expression of CD3 on CD8+ lymphocytes and percent CD8+CD3 lymphocytes was lower, whereas CD4/CD8 ratio was higher among soldiers who failed compared to those who completed the training (Ekblom et al. 2011).

    B) It is well know that energy expenditure increases with increased carried weight, but at heavier loads (>30 kg) we found a disproportionate increase. Our hypothesis is that this is due to inaccurate technique, caused by insufficient strength relative to the carried weight, which may lead to unusual tiredness. In our preliminary results all soldiers had a point, carried weight, above which the work economy decreased. Therefore, it would be relevant to determine each soldier’s maximum optimal weight to carry.

    C) Fatigue and performance in ultra-endurance exercise, such as military efforts, is determined by (in part) other factors compared to traditional endurance sports. One of the most important aspects is energy balance. The total energy expenditure for a 24-h Adventure Race can be as high as 18-20 000 kcal (Enqvist et al. 2010). One reason for fatigue is the substantial energy deficit. Partly because that the profile of amino acids in blood and muscle change (Borgenvik et al. 2012), muscle damage (Wichardt et al. 2011), hormonal changes (Berg et al 2008), and immunological responses (Wallberg et al. 2011, Marklund et al. 2013). This combined indicates that specific supplementations may be needed. We have recently examined the energy balance in military situations. Two situations were 100 h, 78 km by foot in summer alpine terrain (6200 kcal/24h), and 187 h of mixed military tasks (5600 kcal/24h). Even though the allotment of rations was sufficient to cover the energy expenditure the actual intake was substantially lower, energy deficit being approximately 50 % and 33 %, respectively. However, we see large individual differences. If possible, energy availability should be individualized so that heavier soldiers and those with heavier tasks have opportunities to get higher energy supply compared to soldiers with lighter tasks and lower weight.

  • 108.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH.
    S107 - läkemedlet som sätter skräck i USA:s dopingpolis.2008In: Idrott & kunskap, ISSN 1652-6961, Vol. 5, no 3, p. 20-22Article in journal (Other (popular science, discussion, etc.))
  • 109.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Så påverkas hjärtat: Nya avhandlingar: Physiology of Adventure Racing - with emphasis on circulatory response and cardiac fatigue2011In: Svensk IdrottsMedicin, ISSN 1103-7652, Vol. 30, no 4, p. 22-27Article in journal (Other academic)
    Abstract [sv]

    Det övergripande målet med denna avhandling är att redogöra för hur den centrala cirkulationen påverkas av ultra-uthållighetsarbete (multisport/Adventure Racing), samt bidra till kartläggningen av den så kallade "arbetsinducerade hjärtutmattningen".

  • 110.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH.
    Så styrketränar du hjärtat2009In: Idrott & kunskap, ISSN 1652-6961, Vol. 6, no 3, p. 38-42Article in journal (Other (popular science, discussion, etc.))
  • 111.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH.
    Tabata-intervaller: Het och plågsam träningstrend2010In: Idrott & Kunskap, ISSN 1652-6961, Vol. 7, no 5, p. 58-59Article in journal (Other (popular science, discussion, etc.))
  • 112.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Vad vet vi idag om konditionsträning?2010In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 19, no 2, p. 10-13Article in journal (Other academic)
    Abstract [sv]

    Finns det några nyheter om konditionsträning? Eller är det samma gamla skåpmat som ompaketeras och tröskas ett nytt varv? Artikeln är ett försök att klargöra en del grundläggande bitar, samt att plocka fram några nya aspekter på området.

  • 113.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Berglund, Bo
    Department of Medicine, Internal Medicine Unit, Karolinska Institutet, Karolinska University Hospital Solna, Sweden.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Extreme values of NT-proBNP after ultra-endurance exercise in healthy athletes – Related to impaired exercise performance?2011Article in journal (Refereed)
  • 114.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Björkman, Frida
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Edin, Fredrik
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Larsen, Filip
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Regular moist snuff dipping does not affect endurance exercise performance2013Conference paper (Refereed)
    Abstract [en]

    Physiological and medical effects of snuff have previously been obtained either in cross-sectional studies or after snuff administration to non-tobacco users, but the effects of snuff cessation (SC) after several years of daily use on individual level are unknown. 24 participants with >2 years of daily snuff-use were tested before and after >6 weeks SC (SCG), together with a control group (CO) of 11 snuff users who kept their normal habits. Resting heart rate (HR) was significantly lower in SCG after SC. Body mass in SCG group increased by 1.4 ± 1.7 kg and blood pressure (BP) were reduced, but without significant differences between groups. Total cholesterol increased from 4.12 ± 0.54 (95% CI 3.89–4.35) to 4.46 ± 0.70 (95% CI 4.16–4.75) mM/L in SCG, due to increased LDL, and this change was significantly different from CO. Resting values of HDL, C-reactive protein, and free fatty acids (FFA) remained unchanged in both groups. During a four-stage incremental (from 50 to 80% of VO2max) and a prolonged (60 min at 50% of VO2max) cycling test HR and BP were reduced in SCG, while oxygen uptake (VO2), respiratory exchange ratio, blood lactate (bLa) and blood glucose (bGlu) concentration, and rate of perceived exertion were unchanged. All measurements were unchanged in CO. During the prolonged exercise FFA was reduced but there was no significant difference between groups. During the maximal treadmill running test peak values of VO2, pulmonary ventilation (VE), time to exhaustion and bLa were unchanged in both groups. In conclusion, endurance exercise performance (VO2max and maximal endurance time) does not seem to be affected by prolonged snuff use, while effects on cardiovascular risk factors are contradictory.

  • 115.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Börjesson, Mats
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    EKG hos idrottare: Ibland svårt, men alltid viktigt2013In: Svensk Idrottsmedicin, ISSN 1103-752, Vol. 32, no 2, p. 11-13Article in journal (Other academic)
    Abstract [sv]

    Få medicinska underökningar har så lång tradition och så stor symbolisk betydelse som ett EKG (elektrokardiogram). Hjärtat är ju själva symbolen för liv, och ett normalt EKG är en viktig del i att man betecknas som hjärtfrisk.

  • 116.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Unogård, Olof
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Forskningsgruppen för pedagogik, idrott och fritidskultur.
    Kunskapsöversikt: Alkohol och idrott2014Report (Other academic)
    Abstract [sv]

    Alkohol har olika effekter i olika situationer. Innan man med säkerhet kan bedöma dess effekter måste man bestämma vilken situation man är intresserad av. Det gäller dels olika doser av alkohol, och dels olika tidsperspektiv (akut, dagen efter eller under en träningsperiod). Dessutom behöver man ta hänsyn till vilken nivå av idrott som avses. I vissa fall kan alkohol ha små effekter, vilka är försumbara för idrottsmotionärer men kan vara skillnaden mellan succé och fiasko för en elitidrottare.

    Den kunskapsöversikt du nu läser är ett försök att samla och sammanfatta den forskning som i dagsläget finns kring alkohol och idrott. Vår ansats har varit att ta ett så brett grepp som möjligt. I den första halvan avhandlas de fysiologiska aspekterna, som vi grovt sett har delat in i tre delar; effekter idet alkohol påverkade läget (akut), effekter som kvarstår efter att alkoholen lämnat kroppen (kallat ”dagen efter”) och slutligen de effekter som alkoholen har på träningssvaret (kroniska). Den andra halvan av kunskapsöversikten handlar om de psykosociala aspekterna på alkohol och idrott. Även den delen är indelad i tre områden; dryckesmönster bland idrottare, ett externt perspektiv på alkohol och idrott (det vill säga omgivande faktorer, som sponsring och supportrar) samt idrottsrelaterade preventionsinitiativ för alkoholkonsumtion. Utöver dessa områden gör vi i början av vardera kapitel en kort introduktion till området för att klargöra en del grundläggande sammanhang, till exempel under rubrikerna ”Föreningsidrottens roll i ungas liv” och ”Effekter och hälsorisker vid måttlig alkoholkonsumtion”.

  • 117.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Unogård, Olof
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Sämre prestation flera dagar efter festen2014In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 23, no 1, p. 20-25Article in journal (Other academic)
    Abstract [sv]

    Alkohol har effekter på prestationen även långt efter det att den har lämnat kroppen. Försämringen kan hålla i sig upp till 60 timmar efter att det sista glaset är tömt. Det visar en genomgång av de studier som har undersökt alkoholens påverkan på bland annat muskelstyrka och reaktionstider.

  • 118.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH.
    Enqvist, Jonas
    Swedish School of Sport and Health Sciences, GIH.
    Brink-Elfegoun, Thibault
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Johansson, Patrik
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Bakkman, Linda
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Unexpected cardiovascular response during ultra-endurance exercise.2008In: 13th Annual Congress of the European College of Sport Science (ECSS), Estoril, Lissabon, Portugal.: Sport Science by the sea, 2008, p. 142-Conference paper (Other academic)
    Abstract [en]

    During prolonged exercise at fixed work rate heart rate (HR) increases slowly with concomitant decrease in stroke volume (SV) in order to maintain cardiac output. Simultaneously, an increased oxygen uptake (VO2) occurs. In this paper we report an unexpected and previously not observed cardiovascular response to ultra-endurance exercise. Nine well-trained male athletes performed 24-h exercise in a controlled laboratory setting, with altering blocks of kayaking, running and cycling. Each block consisted of 110 min of exercise and 10 min of rest. Measurements (HR, VO2 and blood samples) were conducted during cycling at fixed work rate every 6th hour. The average work intensity was approximately 55 % of respective VO2peak. HR was increased at 6 h with 15 beats/min (13 %) compared to pre-exercise (Pre-Ex), but thereafter unexpectedly returned towards initial values. VO2 on the other hand was increased with 0.22 l/min (10 %) at 6 h and 0.37 l/min (17 %) at 12 h compared to Pre-Ex, and thereafter remained stable. This implies an increased oxygen pulse (VO2/HR) with approximately 10 % compared to Pre-Ex at the later half of the exercise. The cardiovascular drift did not progress continuously, but instead changed drastically when duration exceeded 6 hours. The changes in HR and VO2 might have different and complex explanations. HR drift might be explained mainly by central circulatory adaptation (e.g. desensitisation of cardiac adrenergic receptors) whereas drift in VO2 may depend upon peripheral changes (e.g. decreased mitochondrial efficiency). Consequently, using solely HR for determining exercise intensity and energy expenditure becomes invalid during ultra-endurance exercise, if the cardiovascular drift is not measured and taken into account.

     

  • 119.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Enqvist, Jonas K.
    Inst för kost- och idrottsvetenskap, Göteborgs universitet.
    Stort underskott på energi2011In: Svensk IdrottsMedicin, ISSN 1103-7652, Vol. 30, no 4, p. 12-17Article in journal (Other academic)
    Abstract [sv]

    Det är vanligt att multisportare hamnar i negativ energibalans. Det tycks vara svårt att äta tillräckligt för att täcka det enormt stora energibehovet. Kostrekommendationer för uthållighetsidrottare är heller inte helt gångbara inom multisport.

  • 120.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Enqvist, Jonas K
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Berglund, Bo
    Karolinska Institutet.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Extreme values of cardiac peptide NT-proBNP after ultra-endurance exercise in healthy athletes2010In: Book of Abstracts of the 15th Annual Congress of the European College of Sport Science – 23-26 June 2010 Antalya - Turkey.: Sport Science: Where the cultures meet / [ed] Korkusuz, F., Ertan, H., Tsolakidis, E., 2010, p. 35-36Conference paper (Other academic)
    Abstract [en]

    Introduction: In clinical medicine, natriuretic peptides, including N-terminal B-type natriuretic peptide (NT-proBNP), are used to detect increased myocardial wall tension in conditions such as heart failure. Tachycardia, arrhythmias and physical exercise may also increase these peptides. The clinical reference value is <100 ng/l, and in clinical practice values >300 ng/l are a strong indicators of heart failure, and values >5000 ng/l highly significant for mortality within 3 months.

    Methods: We examined the levels of NT-proBNP after ultra-endurance exercise, and also made an attempt to relate NT-proBNP to performance. The subjects (12 males and 3 females) participated in the Adventure Racing World Championship, a 5-6 days non-stop competition open for mixed gender team of four athletes. They were all healthy, well-trained athletes with experience from several years of competitions at international elite level. Blood samples for determination of NT-proBNP were drawn before exercise (Pre-Ex), at the end of the race (End-Ex) and 24 hours after exercise (Post-Ex). Each athlete rated his/her own performance at the end of the race (i.e. the last 12 hours) on a scale from 1 (good, stronger than teammates), 2 (intermediate) and 3 (poor, got towed in, needed help from teammates). In addition, each athlete was also rated according to the same scale by the other three members of his/her team. Thereafter the four rates were pooled. Note that the rating is in relation to the team rather than the result of the competition.

    Results: The average exercise duration was approx. 150 hours, and the calculated average work intensity was 40 % (in percent of respective VO2peak), including time for rest, change of equipment, and food intake. The levels of NT-proBNP increased from 31 ± 14 (10-56) [mean ± SD (min-max)] at Pre-Ex to 487 ± 648 (52-2480) at End-Ex. At Post-Ex the corresponding levels were 224 ± 219 (12-634). At End-Ex seven subjects had NT-proBNP below the reference value. The rated performance for four of them was 1, and the remaining three were rated as 2. Three of the subjects had markedly higher levels than previously reported (>900 ng/l) and they were rated 3, 3 and 2, respectively.

    Discussion: Extreme levels of NT-proBNP, up to 2500 ng/l, are present after ultra-endurance exercise in healthy athletes without any clinical signs or symptoms of heart failure. On the other hand, these extreme values may be an indicator of cardiac fatigue, previously described after endurance exercise. Furthermore, in this study high levels of NT-proBNP seem to be associated with decreased exercise performance.

  • 121.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Enqvist, Jonas K
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Brink-Elfegoun, Thibault
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Johansson, Patrik H
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Bakkman, Linda
    Swedish School of Sport and Health Sciences, GIH.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Reversed drift in heart rate but increased oxygen uptake at fixed work rate during 24 h ultra-endurance exercise.2010In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 20, no 2, p. 298-304Article in journal (Refereed)
    Abstract [en]

    In this paper we report a reversed drift in heart rate (HR) but increased oxygen uptake (VO(2)) during ultra-endurance exercise. Nine well-trained male athletes performed 24-h exercise in a controlled laboratory setting, with alternating blocks of kayaking, running and cycling. Each block included 110 min of exercise and 10 min of rest, with an average work intensity of approximately 55% of respective VO(2peak). Blood samples were taken and HR and VO(2) measured every 6th hour during steady-state cycling at fixed work rate. As assumed HR was increased at 6 h by 15 +/- 6 beats/min compared with initial level (0 h). Thereafter the drift did not progress continuously, but instead unexpectedly returned toward initial values, although the plasma levels of catecholamines increased continuously during exercise. VO(2) was increased by 0.22 +/- 0.15 L/min (10%) at 6 h and 0.37 +/- 0.18 L/min (17%) at 12 h compared with 0 h, and thereafter remained stable. This implies an increased oxygen pulse (VO(2)/HR) by approximately 10% at the last half of the 24-h exercise compared with 0 h. Consequently, sole use of HR would give inaccurate estimates of exercise intensity and energy expenditure during endurance exercise lasting more than 6 h, and different patterns of cardiovascular drift need to be taken into account.

  • 122.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Enqvist, Jonas K.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    The adventure racing athlete: a physiological profile2013Conference paper (Refereed)
    Abstract [en]

    Introduction: The aim of this study was anthropometric and physiological characterisation of male and female adventure racing athletes (ARs), and also to compare top and bottom finishers in the Adventure Racing World Championship (ARWC) 2006.

    Methods: The physiological profile was developed from oxygen uptake during submaximal and maximal exercise on treadmill, cycle- and kayakergometers. The characterisation study included 15 male and 9 female ARs. Additional anthropometric measurements were obtained from 128 participants in the ARWC.

    Results: The anthropometrics for male ARs were: [mean (95% confidence interval)] age 33 (32-34) years, height 180 (179-181) cm, body mass (BM) 79.4 (78.1-80.7) kg, body fat 17.1 (16.5-17.7) % of BM. Corresponding values for female ARs were: age 31 (30-32) years, height 165 (163-167) cm, BM 61.6 (59.8-63.4) kg, body fat 24.7 (23.6-25.8) % of BM. The men's peak oxygen uptakes were: running 5.02 (4.82-5.22), cycling 4.99 (4.80-5.18), and kayaking 4.05 (3.84-4.26) L/min. Corresponding values for the women were: running 3.26 (3.02-3.50), cycling 3.27 (3.05-3.47), and kayaking 2.59 (2.34-2.84) L/min. The characterized ARs had fractional utilisation in the order: running > cycling > kayaking (best trained in running), indicating that a shift in training regime in favour of kayak training could result in better overall performance. Top male finishers in the ARWC were taller, heavier, had a higher BMI and a trend towards higher body fat than bottom finishers, while there were no such differences among the women. The ARs display a distinct profile, in both anthropometric and physiological aspects, which differs from the specialist athletes'. The ARs have to balance a wide variety of demands, such as sufficient endogenous storage of fat and high ability to carry, against sustained ability to run and perform other BM related tasks.

  • 123.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Flockhart, Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Söderlund, Karin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Hendo, Gina
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Jakobsson, Madeleine
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Pontén, Marjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Effects of prolonged low intensity exercise with energy deficit (military training operation) on markers of muscle protein turnover.2015Conference paper (Refereed)
    Abstract [en]

    Introduction

    It is well known that ultra-endurance exercise, such as Adventure racing and military operations, often induce substantial energy deficits. This suggests a catabolic state, but the exact effects on protein turnover have not yet been sufficiently investigated. The aim of this study was to examine several markers involved in muscle protein turnover before and after a multi-day physically demanding military training operation.

    Methods

    Seven female (age 21 ± 5 years, weight 71.2 ± 6.6 kg) and seventeen male (age 20 ± 1 years, weight 76.6 ± 6.2 kg) performed a 185 hours military training operation. Energy intake was estimated from food supply and energy expenditure was calculated from continuous heart rate and accelerometer recordings. Muscle biopsies were taken from M Vastus Lateralis before and after the operation.

    Results

    A negative energy balance of 1,500-2,000 kcal/24 hours was estimated. Body weight declined 3.4 (95% CI 3.0-3.8) kg and muscle explosive strength, evaluated from squad and counter movement jumps, was reduced 5 and 6 %, respectively, after the operation with no difference between genders. Muscle glycogen content was reduced from 269 ± 58 to 181 ± 44 mmol/kg dry muscle (p<0.05) with no difference between genders. Muscle content of mTOR and p70 as well as MAFbx were unchanged while the protein content of MuRF-1 was significantly down regulated in both genders.

    Discussion

    The study indicated that prolonged low intensity exercise with substantial energy deficit reduces muscle function and muscle glycogen content. Proteins for muscle synthesis mTOR and p70 were unchanged while the down regulation of MuRF-1 indicates a protection against muscle break down during the energy deficit situation, preserving the muscle mass.

  • 124.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Holmberg, Hans-Christer
    Mittuniversitetet.
    Intervallträningen som ger guld2012In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 21, no 2, p. 44-49Article in journal (Other academic)
    Abstract [sv]

    Just nu slipar världens bästa atleter formen för att nå prispallen i OS. Finns det någon optimal träningsform för dem som redan är extremt vältränade? Vad säger vetenskapen om hur man når testvärden som Gunde Svan eller en kenyansk stjärnlöpare?

  • 125.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Larsen, Filip
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Kondition och uthållighet: För träning, tävling och hälsa2013Book (Other (popular science, discussion, etc.))
    Abstract [sv]

    Vilken intervallform är den mest effektiva i syfte att förbättra konditionen? Är det viktigt att ett träningsupplägg styrs av individualisering? Vilka positiva hälsoeffekter medför en förbättrad kondition? Och vad händer i framtiden – kommer drömgränsen under två timmar på maraton, att sprängas?

    En sammanställning och tolkning av den kunskap vi i nuläget har om fysiologi och träningslära.

    Boken Kondition och uthållighet är en sammanställning och tolkning av den kunskap vi i nuläget har om fysiologi och träningslära. Den beskriver en mängd faktorer och situationer kopplade till träning, prestation, utveckling och hälsa. Den vägleder dig som planerar och genomför träningen - aktiv eller tränare – att välja rätt träningsupplägg med hänsyn till träningsgrad och ambitionsnivå.

    Hälsoeffekter och ofattbara prestationer

    Att träna sin kondition medför en lång rad positiva hälsoeffekter såsom ökad livslängd, förbättrad livskvalitet och minskad risk för en mängd sjukdomar. Vid ökad träningsdos genomgår kroppen en rad förändringar för att anpassa sig till de krav som belastningen kräver. Kroppen är lyckligtvis enormt anpassningsbar och får den bara tillräckligt mycket träning kan den lära sig att tåla stora påfrestningar. Detta bidrar till att idrottare som specialiserar sig, och tränar mycket under lång tid, kan uppnå häpnadsväckande prestationer. Ju sämre kondition och uthållighet du har, desto mindre krävs för att du ska förbättra dig. Ju bättre kondition och uthållighet du har, desto hårdare belastning krävs för att du ska förbättra dig ytterligare.

    Pulsträning

    Ett sätt att mäta träningsbelastning är att använda puls och pulsklocka. Författarna, som även har skrivit träningshäftet Pulsträning (SISU Idrottsböcker 2011), förordar en indelning med sex intensitetszoner som baseras på beräkningar av individuella värden på vilo-, tröskel- och maxpuls. Beroende på hur vältränad man är kommer de olika zonerna att hamna mellan olika pulsnivåer. I den här boken beskrivs vad som tränas i de olika zonerna och varför man utför denna träning, samt hur man ska fördela träningsmängden mellan de olika zonerna.

    Intervallträning och individualisering

    Intervallträning innebär att man delar upp ett träningspass i mindre bitar med viloperioder i mellan, vilket möjliggör att hårda träningspass kan genomföras med en större mängd arbete på hög intensitet. Forskning tyder på att högintensiv intervallträning behövs för att man ska få ut så mycket som möjligt av sin konditionsträning. Vid intervallträning är det extra tydligt att man för bästa effekt bör utgå från sin egen förmåga; att man strävar efter en relativ belastning och upplevelse av trötthet, under och efter intervallpassen.

    Bokens upplägg

    Bokens första del går igenom grunderna i fysiologi och den andra delen handlar om vad som händer och vad man behöver tänka på vid planering, utförande och utvärdering av träning och tävling i konditions- och uthållighetsidrotter. Kondition och uthållighet tar också upp områden som återhämtning, skador, olika riskfaktorer och näringslära, vilka har en direkt betydelse för konditionsträning, oavsett om det handlar om att vinna OS eller träning för hälsa och ett långt aktivt liv.

  • 126.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Larsen, Filip
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Pulsträning2011Book (Other (popular science, discussion, etc.))
    Abstract [sv]

    Att träna pulsbaserat skapar perfekta förutsättningarna för en positiv utveckling av din kondition eftersom du tränar utifrån din egen förmåga. Pulsen hjälper dig att träna på rätt nivå på de enskilda träningspassen och kan användas vid all form av konditionsträning. I häftet Pulsträning lär du dig grunderna för att träna med puls och hur du genom att använda olika belastningar kan uppnå olika effekter av din träning.  Du får också förslag på olika tester som både hjälper dig att träna effektivare och skapar motivation.

  • 127.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Lind, Britta
    School of Technology and Health, Royal Institute of Technology (KTH).
    Enqvist, Jonas K.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Mårtensson, Mattias
    School of Technology and Health, Royal Institute of Technology (KTH).
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Brodin, Lars-Åke
    School of Technology and Health, Royal Institute of Technology (KTH).
    No evidence of cardiac fatigue in tissue velocity curves at rest after 6 days of ultra-endurance exercise.2011Article in journal (Refereed)
  • 128.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Ståhlberg, Marcus
    Institutionen för Medicin, Enheten för kardiologi, Karolinska Universitetssjukhuset.
    Larsen, Filip
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Braunschweig, Frieder
    Institutionen för Medicin, Enheten för kardiologi, Karolinska Universitetssjukhuset.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Late cardiovascular drift observable during ultra endurance exercise.2011In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 43, no 7, p. 1162-1168Article in journal (Refereed)
    Abstract [en]

    Introduction: The present study investigates the adaptation of the central circulation to ultraenduranceexercise, including the relative contributions of changes in stroke volume (SV) andarterio-venous oxygen difference (a-v O2 diff) to the increased oxygen pulse (VO2/HR).Methods: We evaluated subjects undergoing 12h of mixed exercise at controlled intensity(n=8) and a 53h Adventure race (n=20). Heart rate (HR), oxygen uptake (VO2), and cardiacoutput determined using non-invasive gas rebreathing (CORB) were measured during cyclingat fixed work rate after 0, 4, 8, 12 hours, and 0, 20, and 53 hours of continuous exercise in the12 and 53 h protocol, respectively.Results and Conclusion: The central circulation changed in several steps in response to ultraenduranceexercise. Compared to initial levels, VO2 was increased at every time-point measured.The increase was attributed to peripheral adaptations, confirmed by a close correlation betweenchange in VO2 and change in a-v O2 diff. The first step of the circulatory response was typical ofnormal (early) cardiovascular drift, with increased HR and concomitantly decreased SV andVO2/HR, occurring over the first 4-6 h. The second step, which continued until approximately 12h, included reversed HR-drift, with normalization of SV and VO2/HR. When exercise continueduntil 50 h late cardiovascular drift was noted, characterized by increased VO2/HR, (indicatingmore efficient energy distribution), decreased peripheral resistance, increased stroke volume, anddecreased work of the heart. Since cardiac output was maintained at all time points we interpretthe changes as physiologically appropriate adaptations to ultra-endurance exercise.

  • 129.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Waggott, Daryl
    Ashley Lab, Stanford University.
    Wheeler, Matthew
    Ashley Lab, Stanford University.
    Lindholm, Malene
    Ashley Lab, Stanford University.
    The ELITE project (Exercise at the Limit - Inherited Traits of Endurance) - the genetic profiles of the best endurance athletes in the world.2017Conference paper (Refereed)
    Abstract [en]

    Cardiovascular health exists as a spectrum of wellness and disease states. Moreover, a significant portion of what defines these states is due to genetics. We hypothesize that there exist genes and pathways that dually contribute to both disease and extreme health states. Interrogating the ‘adaptive’ tail of the distribution for individuals with extreme phenotypes, such as high maximum oxygen uptake (VO2max) in endurance athletes, will inform prevention, cause and treatment of pathogenic (‘maladaptive’) conditions. 1 To date, most genetic studies in the athlete population have examined a subset of genes (out of more than 21,000 in the genome), using small sample sizes and qualitative measures of performance. To the best of our knowledge, there has not been a comprehensive genetic study of endurance athletes with strict quantitative eligibility criteria.2-4

    The ELITE project (Exercise at the Limit – Inherited Traits of Endurance) intends to investigate the world’s best endurance athletes, i.e. individuals with extremely high VO2max. A primary goal is to determine what role genetic variation plays in athletic ability. One of the ancillary goals of the project is to understand the unique genetic differences contributing to extreme fitness in women versus men. We will sequence and analyze the genomes of elite level competitive athletes from various countries (including USA, Scandinavia, UK, Japan, and Brazil) who are highly successful in one of several endurance sports (such as running, cross country skiing, triathlon, cycling, rowing). We have recruited 750 elite athletes (142 women and 608 men) who have been consented and undergone enhanced whole exome sequencing and/or MEGA chip GWAS analysis. Inclusion criteria for the study restricts to the highest tail end (>99.98th percentile or 1/5000), i.e. VO2max >63 ml/kg for women and >75 ml/kg for men. Even with differential eligibility, skewed recruitment (1:4) is a challenge.

    Our preliminary results show tantalizing evidence for potentially beneficial genetic variants in several highly plausible genes. Additionally, pilot burden testing on a subset of the athletes also showed promising results. While already promising, rigorous analysis, increased sample size and orthogonal replication is required as our next step.

     

    1. Mattsson CM, Wheeler M, Waggott D, Caleshu C, Ashley EA. Sports genetics moving forward - lessons learned from medical research. Physiol Genomics. 2016; 48(3):175-182.
    2. Bouchard C, Sarzynski MA, Rice TK, Kraus WE, Church TS, Sung YJ, Rao DC, Rankinen T. Genomic predictors of the maximal O₂ uptake response to standardized exercise training programs. J Appl Physiol (1985). 2011; 110(5):1160-70.
    3. Eynon N, Morán M, Birk R, Lucia A. The champions' mitochondria: is it genetically determined? A review on mitochondrial DNA and elite athletic performance. Physiol Genomics. 2011;43(13):789-98.
    4. Pitsiladis YP, Tanaka M, Eynon N, Bouchard C, North KN, Williams AG, Collins M, Moran CN, Britton SL, Fuku N, Ashley EA, Klissouras V, Lucia A, Ahmetov II, de Geus E, Alsayrafi M; Athlome Project Consortium. Athlome Project Consortium: a concerted effort to discover genomic and other "omic" markers of athletic performance. Physiol Genomics. 2016;48(3):183-90.
  • 130.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Wheeler, Matthew
    Stanford University.
    Waggott, Daryl
    Stanford University.
    Caleshu, Colleen
    Stanford University.
    Ashley, Euan A.
    Stanford University.
    Sports genetics moving forward - lessons learned from medical research2016In: Physiological Genomics, ISSN 1094-8341, E-ISSN 1531-2267, Vol. 48, no 3, p. 175-182Article in journal (Refereed)
    Abstract [en]

    Sports genetics can take advantage of lessons learned from human disease genetics. By righting past mistakes and increasing scientific rigor, the breadth and depth of knowledge in the field can be magnified. We present an outline of challenges facing sports genetics in the light of experiences from medical research.

    Sports performance is complex, resulting from a combination of a wide variety of different traits and attributes.  Improving sports genetics will foremost require analyses based on detailed phenotyping. In order to find widely valid, reproducible common variants associated with athletic phenotypes, study sample sizes must be dramatically increased. One paradox is that in order to confirm relevance, replications in specific populations must be undertaken. Family studies of athletes may facilitate the discovery of rare variants with large effects on athletic phenotypes. The complexity of the human genome, combined with the complexity of athletic phenotypes, will require additional metadata and biological validation to identify a comprehensive set of genes involved.

    Analysis of personal genetic and multiomic profiles contribute to our conceptualization of precision medicine; the same will be the case in precision sports science. In the refinement of sports genetics it is essential to evaluate similarities and differences between genders and among ethnicities. Sports genetics to date have been hampered by small sample sizes and biased methodology which can lead to erroneous associations and overestimation of effect sizes. Consequently, currently available genetic tests based on these inherently limited data cannot predict athletic performance with any accuracy.

  • 131.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Wichardt, Emma
    Idrottsmedicin, Umeå universitet.
    NSAID inom multisport2011In: Svensk IdrottsMedicin, ISSN 1103-7652, Vol. 30, no 4, p. 18-21Article in journal (Other academic)
    Abstract [sv]

    Användning av NSAID är mycket vanligt bland deltagare i längre multisporttävlingar. Ofta i tron att NSAID påskyndar återhämtningen, trots att kunskapen om dess påverkan vid idrott är begränsad. Det är till och med möjligt att NSAID har motsatt effekt och istället påverkar muskelåterhämtning och -uppbyggnad negativt.

  • 132. Michaud, B.
    et al.
    Jackson, M.
    Arndt, Anton
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Lundberg, A.
    Begon, M.
    Determining in vivo sternoclavicular, acromioclavicular and glenohumeral joint centre locations from skin markers, CT-scans and intracortical pins: A comparison study2016In: Medical Engineering and Physics, ISSN 1350-4533, E-ISSN 1873-4030, Vol. 38, no 3, p. 290-296Article in journal (Refereed)
    Abstract [en]
    • CoR were located using anatomical, predictive, functional and imaging-based methods.
    • Gold-standard locations were obtained using intracortical pins.
    • Sternoclavicular joint: our findings are in agreement with ISB (Wu, 2005).
    • Acromioclavicular joint: anatomical method of by van der Helm (1996) is suggested.
    • Glenohumeral joint: the regression equation of Rab (2002) is suggested. 

    To describe shoulder motion the sternoclavicular, acromioclavicular and glenohumeral joint centres must be accurately located. Within the literature various methods to estimate joint centres of rotation location are proposed, with no agreement of the method best suited to the shoulder. The objective of this study was to determine the most reliable non-invasive method for locating joint centre locations of the shoulder complex. Functional methods using pin mounted markers were compared to anatomical methods, functional methods using skin mounted markers, imaging-based methods using CT-scan data, and regression equations. Three participants took part in the study, that involved insertion of intracortical pins into the clavicle, scapula and humerus, a CT-scan of the shoulder, and finally data collection using a motion analysis system. The various methods to estimate joint centre location did not all agree, however suggestions about the most reliable non-invasive methods could be made. For the sternoclavicular joint, the authors suggest the anatomical method using the most ventral landmark on the sternoclavicular joint, as recommended by the International Society of Biomechanics. For the acromioclavicular joint, the authors suggest the anatomical method using the landmark defined as the most dorsal point on the acromioclavicular joint, as proposed by van der Helm. For the glenohumeral joint, the simple regression equation of Rab is recommended.

  • 133.
    Moberg, Marcus
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Apró, William
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Gerrit, van Hall
    Holmberg, Hans-Christer
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Activation of mTORC1 by leucine is potentiated by branched chain amino acids and even more so by essential amino acids following resistance exercise2016In: American Journal of Physiology - Cell Physiology, ISSN 0363-6143, E-ISSN 1522-1563, Vol. 310, no 11, p. C874-C884Article in journal (Refereed)
    Abstract [en]

    Protein synthesis is stimulated by resistance exercise and intake of amino acids, in particular leucine. Moreover, activation of mTORC1 signaling by leucine is potentiated by the presence of other essential amino acids (EAA). However, the contribution of the branched-chain amino acids (BCAA) to this effect is yet unknown. Here we compare the stimulatory role of leucine, BCAA and EAA ingestion on anabolic signaling following exercise. Accordingly, eight trained volunteers completed four sessions of resistance exercise during which they ingested either placebo, leucine, BCAA or EAA (including the BCAA) in random order. Muscle biopsies were taken at rest, immediately after exercise and following 90 and 180 min of recovery. Following 90 min of recovery the activity of S6K1 was greater than at rest in all four trials (Placebo<Leucine<BCAA<EAA; P<0.05 time x supplement), with a 9-fold increase in the EAA trial. At this same time-point phosphorylation of 4E-BP1 at Thr37/46 was unaffected by supplementation, while that of Thr46 alone exhibited a pattern similar to that of S6K1, being 18% higher with EAA than BCAA. However, after 180 min of recovery this difference between EAA and BCAA had disappeared, although with both these supplements the increases were still higher than with leucine (40%, P<0.05) and placebo (100%, P<0.05). In summary, EAA ingestion appears to stimulate translation initiation more effectively than the other supplements, although the results also suggest that this effect is primarily attributable to the BCAA.

  • 134.
    Moberg, Marcus
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Apró, William
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Ohlsson, Inger
    Pontén, Marjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Villanueva, Antonio
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Absence of leucine in an essential amino acid supplement reduces activation of mTORC1 signalling following resistance exercise in young females.2014In: Applied Physiology, Nutrition and Metabolism, ISSN 1715-5312, E-ISSN 1715-5320, Vol. 39, no 2, p. 183-94Article in journal (Refereed)
    Abstract [en]

    The purpose of the study was to investigate the specific effect of leucine on mTORC1 signalling and amino acid metabolism in connection with resistance exercise. Comparisons were made between ingestion of supplements with and without leucine. Eight young women performed leg press exercise on 2 occasions. In randomized order they received either an aqueous solution of essential amino acids with leucine (EAA) or without leucine (EAA-Leu), given as small boluses throughout the experiment. Muscle biopsies were taken after an overnight fast before exercise and 1 and 3 h postexercise and samples of blood were taken repeatedly during the experiment. Plasma and muscle concentrations of leucine rose 60%-140% (p < 0.05) with EAA and fell 35%-45% (p < 0.05) with the EAA-Leu supplement. In the EAA-trial, plasma and muscle levels of tyrosine (not present in the supplement) and the sum of the EAA were 15%-25% (p < 0.05) lower during recovery. Phosphorylation of mTOR and p70S6k was elevated to a larger extent following 1 h of recovery with leucine in the supplement (120% vs. 49% (p < 0.05) and 59- vs. 8-fold (p < 0.05) for EAA and EAA-Leu, respectively). The levels of MAFbx and MuRF-1 mRNA and of the corresponding proteins were not significantly altered after 3 h recovery from exercise. In conclusion, the presence of leucine in the supplement enhances the stimulatory effect on mTORC1 signalling and reduces the level of tyrosine and the sum of the EAA in muscle and plasma, suggesting a stimulation of protein synthesis and (or) inhibition of breakdown, leading to improvement in net protein balance.

  • 135. Montenegro, Marcelo F
    et al.
    Sundqvist, Michaela L
    Larsen, Filip J
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Zhuge, Zhengbing
    Carlström, Mattias
    Weitzberg, Eddie
    Lundberg, Jon O
    Blood Pressure-Lowering Effect of Orally Ingested Nitrite Is Abolished by a Proton Pump Inhibitor.2017In: Hypertension, ISSN 0194-911X, E-ISSN 1524-4563, Vol. 69, no 1, p. 23-31Article in journal (Refereed)
    Abstract [en]

    Inorganic nitrate and nitrite from dietary and endogenous sources are metabolized to NO and other bioactive nitrogen oxides that affect blood pressure. The mechanisms for nitrite bioactivation are unclear, but recent studies in rodents suggest that gastric acidity may influence the systemic effects of this anion. In a randomized, double-blind, placebo-controlled crossover study, we tested the effects of a proton pump inhibitor on the acute cardiovascular effects of nitrite. Fifteen healthy nonsmoking, normotensive subjects, aged 19 to 39 years, were pretreated with placebo or esomeprazole (3×40 mg) before ingesting sodium nitrite (0.3 mg kg(-1)), followed by blood pressure monitoring. Nitrite reduced systolic blood pressure by a maximum of 6±1.3 mm Hg when taken after placebo, whereas pretreatment with esomeprazole blunted this effect. Peak plasma nitrite, nitrate, and nitroso species levels after nitrite ingestion were similar in both interventions. In 8 healthy volunteers, we then infused increasing doses of sodium nitrite (1, 10, and 30 nmol kg(-1) min(-1)) intravenously. Interestingly, although plasma nitrite peaked at similar levels as with orally ingested nitrite (≈1.8 µmol/L), no changes in blood pressure were observed. In rodents, esomeprazole did not affect the blood pressure response to the NO donor, DEA NONOate, or vascular relaxation to nitroprusside and acetylcholine, demonstrating an intact downstream NO-signaling pathway. We conclude that the acute blood pressure-lowering effect of nitrite requires an acidic gastric environment. Future studies will reveal if the cardiovascular complications associated with the use of proton pump inhibitors are linked to interference with the nitrate-nitrite-NO pathway.

  • 136.
    Moritani, Toshio
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Fuchi, Tokio
    Oddsson, Lars
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Andersson, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Applications of fast fourier transform (FFT) in noninvasive physiological measurements in sport science.1988In: J Sports Med Sci (Japan), Vol. 2, no 1, p. 27-42Article in journal (Refereed)
  • 137. Newsholme, Eric A
    et al.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Branched-chain amino acids and central fatigue.2006In: Journal of Nutrition, ISSN 0022-3166, E-ISSN 1541-6100, Vol. 136, no 1 Suppl, p. 274S-6SArticle in journal (Refereed)
    Abstract [en]

    An account of the tryptophan (Trp)-5-hydroxytryptamine (5-HT)-central fatigue theory is provided and an explanation of how oral administration of BCAAs can decrease fatigue on the basis of this theory is given. The rate-limiting step in the synthesis of 5-HT is the transport of Trp across the blood-brain barrier. This transport is influenced by the fraction of Trp available for transport into the brain and the concentration of the other large neutral amino acids, including the BCAAs, which are transported via the same carrier system. During endurance exercise, there is an uptake of Trp by the brain, suggesting that this may increase the synthesis and release of 5-HT in the brain. Oral intake of BCAAs may reduce this uptake and also brain 5-HT synthesis and release, thereby delaying fatigue. Other hypotheses for the effect of BCAAs on central fatigue are included.

  • 138. Nielsen, Joachim
    et al.
    Mogensen, Martin
    Vind, Birgitte F
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Højlund, Kurt
    Schrøder, Henrik D
    Ortenblad, Niels
    Increased subsarcolemmal lipids in type 2 diabetes: effect of training on localization of lipids, mitochondria, and glycogen in sedentary human skeletal muscle.2010In: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 298, no 3, p. E706-13Article in journal (Refereed)
    Abstract [en]

    The purpose of the study was to investigate the effect of aerobic training and type 2 diabetes on intramyocellular localization of lipids, mitochondria, and glycogen. Obese type 2 diabetic patients (n = 12) and matched obese controls (n = 12) participated in aerobic cycling training for 10 wk. Endurance-trained athletes (n = 15) were included for comparison. Insulin action was determined by euglycemic-hyperinsulinemic clamp. Intramyocellular contents of lipids, mitochondria, and glycogen at different subcellular compartments were assessed by transmission electron microscopy in biopsies obtained from vastus lateralis muscle. Type 2 diabetic patients were more insulin resistant than obese controls and had threefold higher volume of subsarcolemmal (SS) lipids compared with obese controls and endurance-trained subjects. No difference was found in intermyofibrillar lipids. Importantly, following aerobic training, this excess SS lipid volume was lowered by approximately 50%, approaching the levels observed in the nondiabetic subjects. A strong inverse association between insulin sensitivity and SS lipid volume was found (r(2)=0.62, P = 0.002). The volume density and localization of mitochondria and glycogen were the same in type 2 diabetic patients and control subjects, and showed in parallel with improved insulin sensitivity a similar increase in response to training, however, with a more pronounced increase in SS mitochondria and SS glycogen than in other localizations. In conclusion, this study, estimating intramyocellular localization of lipids, mitochondria, and glycogen, indicates that type 2 diabetic patients may be exposed to increased levels of SS lipids. Thus consideration of cell compartmentation may advance the understanding of the role of lipids in muscle function and type 2 diabetes.

  • 139.
    Nordlund Ekblom, Maria M
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Improvements in dynamic plantar flexor strength after resistance training are associated with increased voluntary activation and V: M ratio.2010In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 109, no 1, p. 19-26Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate if, and via what mechanisms, resistance training of the plantar flexor muscles affects voluntary activation during maximal voluntary eccentric and concentric muscle actions. Twenty healthy subjects were randomized into a resistance training group (N = 9) or a passive control group (N = 11). Training consisted of 15 sessions of unilateral mainly eccentric plantar flexor exercise over a 5-week period. During pre- and post-training testing, dynamic plantar flexor strength was measured and voluntary activation was calculated using the twitch interpolation technique. The Soleus H-reflex was used to assess motoneurone excitability and presynaptic inhibition of Ia-afferents whereas the Soleus V-wave to test for both changes in presynaptic inhibition of Ia-afferents and changes in supraspinal inputs to the motoneurone pool. H-reflexes, V-waves, supramaximal M-waves and twitches were evoked as the foot was moved at 5 degrees (.)s(-1) through an angle of 90 degrees during passive ankle rotations (passive H and M) and during maximal voluntary concentric and eccentric plantar flexion (MVC H, M and V-wave). Training induced significant improvements in plantar flexor strength and voluntary activation during both concentric and eccentric maximal voluntary actions. Soleus passive and MVC H:M ratios remained unchanged after training, whereas the Soleus V:M ratio was increased during both concentric and eccentric contractions after training. No change was seen in the control group for any of the parameters. The enhanced voluntary strength could be attributed partly to an increase in voluntary activation induced by eccentric training. Since the passive and MVC H:M ratios remained unchanged, the increase in activation is probably not due to decreased presynaptic inhibition. The increased V:M ratio for both action types indicate, that increased voluntary drive from supraspinal centers and/or modulation in afferents other than Ia:s, may have contributed to such an increase in voluntary activation.

  • 140.
    Norrbrink, Cecilia
    et al.
    Department of Clinical Sciences, Karolinska Institutet Danderyd Hospital, Stockholm.
    Lindberg, Thomas
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Wahman, Kerstin
    Department of Neurobiology, Care Sciences and Society (NVS), Division of Neurorehabilitation, Karolinska Institutet.
    Bjerkefors, Anna
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Effects of an exercise programme on musculoskeletal and neuropathic pain after spinal cord injury - results from a seated double-poling ergometer study2012In: Spinal Cord, ISSN 1362-4393, E-ISSN 1476-5624, Vol. 50, no 6, p. 457-461Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: To assess pain relieving effects of an intensive exercise programme on a seated double-poling ergometer in individuals with spinal cord injury (SCI).

    SETTING: Stockholm, Sweden.

    METHODS: A total of 13 wheelchair-dependent individuals with a thoracic or lumbar SCI were recruited to a 10-week training period (three times weekly) assessing the effects of regular training on upper-body strength, aerobic and mechanical power, and crossover effects on functional performance, as well as cardiovascular risk factors. Eight of the participants reported pain and were included in this exploratory pain protocol and assessed using the International SCI Basic Pain Data set, the Wheelchair Users' Shoulder Pain Index and International SCI Quality of Life Basic Data set.

    RESULTS: For those with neuropathic pain, median pain intensity ratings decreased from 5 on a 0-10 numerical rating scale at base-line to 3 at the end of study, and four of seven participants reported an improvement on the Patient Global Impression of Change scale. For those with musculoskeletal pain (n = 5), median pain intensity ratings improved from 4 at baseline to 0 at the end of study. All but one rated no musculoskeletal pain at all at the end of study and number of days with pain per week decreased from 5.5 to 0.7. None of the participants developed pain, because of overuse during the training period and few reported unwanted side effects.

    CONCLUSION: Considering its promising effects and safety, an intensive exercise programme can be tried for treating musculoskeletal pain and also neuropathic pain following SCI.

  • 141. Nybo, Lars
    et al.
    Nielsen, Bodil
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Moller, Kirsten
    Secher, Niels
    Neurohumoral responses during prolonged exercise in humans.2003In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 95, no 3, p. 1125-31Article in journal (Refereed)
    Abstract [en]

    This study examined neurohumoral alterations during prolonged exercise with and without hyperthermia. The cerebral oxygen-to-carbohydrate uptake ratio (O2/CHO = arteriovenous oxygen difference divided by arteriovenous glucose difference plus one-half lactate), the cerebral balances of dopamine, and the metabolic precursor of serotonin, tryptophan, were evaluated in eight endurance-trained subjects during exercise randomized to be with or without hyperthermia. The core temperature stabilized at 37.9 +/- 0.1 degrees C (mean +/- SE) in the control trial, whereas it increased to 39.7 +/- 0.2 degrees C in the hyperthermic trial, with a concomitant increase in perceived exertion (P < 0.05). At rest, the brain had a small release of tryptophan (arteriovenous difference of -1.2 +/- 0.3 micromol/l), whereas a net balance was obtained during the two exercise trials. Both the arterial and jugular venous dopamine levels became elevated during the hyperthermic trial, but the net release from the brain was unchanged. During exercise, the O2/CHO was similar across trials, but, during recovery from the hyperthermic trial, the ratio decreased to 3.8 +/- 0.3 (P < 0.05), whereas it returned to the baseline level of approximately 6 within 5 min after the control trial. The lowering of O2/CHO was established by an increased arteriovenous glucose difference (1.1 +/- 0.1 mmol/l during recovery from hyperthermia vs. 0.7 +/- 0.1 mmol/l in control; P < 0.05). The present findings indicate that the brain has an increased need for carbohydrates during recovery from strenuous exercise, whereas enhanced perception of effort as observed during exercise with hyperthermia was not related to alterations in the cerebral balances of dopamine or tryptophan.

  • 142.
    Oddsson, Lars
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Moritani, Toshio
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Andersson, Eva A
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Differences between males and females in EMG and fatiguability of lumbar back muscles.1991In: Electromyographical Kinesiology / [ed] Anderson PA, Hobart DJ, Danoff JV, Amsterdam: Elsevier Science Publisher (Biomedical Division) , 1991, p. 295-298Chapter in book (Other academic)
  • 143. Ortenblad, Niels
    et al.
    Macdonald, Will A
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Glycolysis in contracting rat skeletal muscle is controlled by factors related to energy state.2009In: Biochemical Journal, ISSN 0264-6021, E-ISSN 1470-8728, Vol. 420, no 2, p. 161-8Article in journal (Refereed)
    Abstract [en]

    The control of glycolysis in contracting muscle is not fully understood. The aim of the present study was to examine whether activation of glycolysis is mediated by factors related to the energy state or by a direct effect of Ca2+ on the regulating enzymes. Extensor digitorum longus muscles from rat were isolated, treated with cyanide to inhibit aerobic ATP production and stimulated (0.2 s trains every 4 s) until force was reduced to 70% of initial force (control muscle, referred to as Con). Muscles treated with BTS (N-benzyl-p-toluene sulfonamide), an inhibitor of cross-bridge cycling without affecting Ca2+ transients, were stimulated for an equal time period as Con. Energy utilization by the contractile apparatus (estimated from the observed relation between ATP utilization and force-time integral) was 60% of total. In BTS, the force-time integral and ATP utilization were only 38 and 58% of those in Con respectively. Glycolytic rate in BTS was only 51% of that in Con but the relative contribution of ATP derived from PCr (phosphocreatine) and glycolysis and the relation between muscle contents of PCr and Lac (lactate) were not different. Prolonged cyanide incubation of quiescent muscle (low Ca2+) did not change the relation between PCr and Lac. The reduced glycolytic rate in BTS despite maintained Ca2+ transients, and the unchanged PCr/Lac relation in the absence of Ca2+ transients, demonstrates that Ca2+ is not the main trigger of glycogenolysis. Instead the preserved relative contribution of energy delivered from PCr and glycolysis during both conditions suggests that the glycolytic rate is controlled by factors related to energy state.

  • 144. Peolsson, Michael
    et al.
    Löfstedt, Tommy
    Vogt, Susanna
    Stenlund, Hans
    Arndt, Anton
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Trygg, Johan
    Modelling human musculoskeletal functional movements using ultrasound imaging.2010In: BMC Medical Imaging, ISSN 1471-2342, E-ISSN 1471-2342, Vol. 10, p. 9-Article in journal (Refereed)
    Abstract [en]

    This new objective method is a powerful tool to use when visualising tissue activity and dynamics of musculoskeletal ultrasound registrations.

  • 145.
    Psilander, Niklas
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll. Karolinska institutet, Inst för fysiologi och farmakologi / Dept of Physiology and Pharmacology .
    The effect of different exercise regimens on mitochondrial biogenesis and performance2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Endurance training is a powerful tool to improve both health and performance. Physical activity is now recognized as an effective treatment and prevention therapy for a wide range of diseases. One of the most profound adaptations to endurance training is increased mitochondrial function and content within the exercising muscles. Mitochondrial quality and quantity are closely related to several of the positive health effects reported after training. High mitochondrial content strongly correlates with muscle oxidative capacity and endurance performance. Even though it is well known that endurance training increases mitochondrial content, it is unclear which type of training is the most efficient to promote mitochondrial biogenesis. Therefore, the basis for current exercise recommendations relative to mitochondrial biogenesis is poor or absent. Thus, the main objective of this thesis was to evaluate the effect of different training strategies on mitochondrial biogenesis.

    Recent developments in molecular methods have made it possible to study the initial adaptations to training through measurement of mRNA gene expression of exercise induced genes. One such gene is transcriptional coactivator peroxisome proliferator–activated receptor-γ coactivator-1α (PGC-1α). PGC-1α is a key regulator of mitochondrial biogenesis and the expression of PGC-1α can therefore be used as a marker of this process.

    The first four studies presented in this thesis are acute exercise studies where two different exercise models were compared using a cross-over design. Muscle biopsies were obtained pre and post exercise and analysed for gene expression and glycogen, apart from study II. The final study was a long-term training study where muscle biopsies were obtained before and after the training period and analysed for mitochondrial enzyme activities and protein content.

    Study I: The expression of PGC-1α and related genes were examined after 90 min of continuous and interval exercise in untrained subjects. The exercise protocols influenced the expression of genes involved in mitochondrial biogenesis and oxidative metabolism in a similar manner. Both interval and continuous exercise were potent training strategies for relatively sedentary individuals.

    Study II: The expression of PGC-1α and related genes were examined after low-volume sprint interval (SIT) and high-volume interval (IE) exercise in highly trained cyclists. SIT induced a similar increase in PGC-1α expression as IE despite a much lower time commitment and work completed. Sprint interval exercise might, therefore, be a time efficient training strategy for highly trained individuals.

    Study III: The expression of PGC-1α and related genes, as well as the activity of upstream proteins, were examined after concurrent (ER: cycling + leg press) and single-mode (E: cycling only) exercise in untrained subjects. PGC-1α expression doubled after ER compared with E. It was concluded that concurrent training might be beneficial for mitochondrial biogenesis in untrained individuals.

    Study IV: The expression of PGC-1α and related genes were examined after exercise performed with low (LG) and normal (NG) muscle glycogen in well-trained cyclists. PGC-1α expression increased approximately three times more after LG compared with NG. This finding suggested that low glycogen exercise is a potent inducer of mitochondrial biogenesis in well-trained individuals.

    Study V: Mitochondrial enzyme activity, protein content and endurance performance were examined after eight weeks of concurrent (ES: cycling + leg press) or single-mode (E: cycling only) training in cyclists. ES did not affect enzyme activity, protein content or endurance performance differently than E. The beneficial effect previously observed in untrained subjects did not translate to higher numbers of mitochondria in trained individuals.

    In three of the studies, I, III, and IV, both glycogen and PGC-1α expression were measured after exercise. These data were then pooled and examined. The highest PGC-1α mRNA expression levels were identified when glycogen levels were low, and vice versa. This suggests that low glycogen might play an important role in the regulation of mitochondrial biogenesis also during interval and concurrent strength and endurance exercise.

    In conclusion, key markers of mitochondrial biogenesis can be effectively up-regulated by interval, concurrent and low glycogen exercise. A possible explanation for this might be that though the exercise protocols are quite divergent in nature, they all have a pronounced effect on muscle glycogen and/or perturbation in energetic stress.

  • 146.
    Psilander, Niklas
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Frank, Per
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Flockhart, Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Adding strength to endurance training does not enhance aerobic capacity in cyclists2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, no 4, p. e353-e359Article in journal (Refereed)
    Abstract [en]

    The molecular signaling of mitochondrial biogenesis is enhanced when resistance exercise is added to a bout of endurance exercise. The purpose of the present study was to examine if this mode of concurrent training translates into increased mitochondrial content and improved endurance performance. Moderately trained cyclists performed 8 weeks (two sessions per week) of endurance training only (E, n = 10; 60-min cycling) or endurance training followed by strength training (ES, n = 9; 60-min cycling + leg press). Muscle biopsies were obtained before and after the training period and analyzed for enzyme activities and protein content. Only the ES group increased in leg strength (+19%, P < 0.01), sprint peak power (+5%, P < 0.05), and short-term endurance (+9%, P < 0.01). In contrast, only the E group increased in muscle citrate synthase activity (+11%, P = 0.06), lactate threshold intensity (+3%, P < 0.05), and long-term endurance performance (+4%, P < 0.05). Content of mitochondrial proteins and cycling economy was not affected by training. Contrary to our hypothesis, the results demonstrate that concurrent training does not enhance muscle aerobic capacity and endurance performance in cyclists.

  • 147.
    Psilander, Niklas
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Kristoffer, Toldnes Cumming
    NIH, Norwegian School of Sport and Health Sciences, Oslo, Norway.
    Engström, Björn
    Capio Atro Clinic, Sophiahemmet, Stockholm, Sweden.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Raastad, Truls
    2NIH, Norwegian School of Sport and Health Sciences, Oslo, Norway .
    Retention of myonuclei after grave atrophy in human skeletal muscle, a case study2017In: Acta Physiologica Volume 219, Issue S710 February 2017, 2017, Vol. 219, p. 14-43Conference paper (Refereed)
    Abstract [en]

    Introduction: the current textbook model suggests that the myonuclear domain size is constant for muscle fibers in both their atrophic and hypertrophic state. However, recent animal studies show that myonuclear content is maintained after atrophy leading to a decreased myonuclear domain size (Gundersen et al. J Physiol. 2008 Jun 1;586(11):2675-81). This remains to be investigated in human skeletal muscle and the aim of the present study was therefore to study the effect of grave atrophy on myonuclear content and domain size in the vastus medialis muscle.

    Materials and Methods: biopsies were obtained from vastus medialis on a 22 year old female patient before and 6 weeks after an anterior cruciate ligament reconstructionand meniscus repair surgery. Histochemical analyses were done to analyze fiber cross sectional area (CSA), fiber type composition and number of myonuclei per fiber.

    Results: the CSA of type II muscle fibers decreased by 35% (from 4297±55 to 2807±64 µm2) whereas the number of myonuclei per fiber remained stable (3.4±0.4 and 3.9±0.5, pre and post respectively). The nuclear domain size was thereby decreased by ~40% (from 1255 to 722 µm2). There were only minor changes in type I muscle fiber CSA, myonuclei content and domain size.

    Conclusion: in line with previous findings from animal studies, the present case study shows that the number of myonuclei per fiber is maintained and the domain size is reduced in human skeletal muscle after immobilization induced atrophy.

  • 148.
    Psilander, Niklas
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Wang, Li
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Westergren, Jens
    Tonkonogi, Michail
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Mitochondrial gene expression in elite cyclists: effects of high-intensity interval exercise.2010In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 110, no 3, p. 597-606Article in journal (Refereed)
    Abstract [en]

    Little is known about the effect of training on genetic markers for mitochondrial biogenesis in elite athletes. We tested the hypothesis that low-volume sprint interval exercise (SIE) would be as effective as high-volume interval exercise (IE). Ten male cyclists competing on national elite level (W (max) 403 ± 13 W, VO(2peak) 68 ± 1 mL kg(-1) min(-1)) performed two interval exercise protocols: 7 × 30-s "all-out" bouts (SIE) and 3 × 20-min bouts at ~87% of VO(2peak) (IE). During IE, the work was eightfold larger (1,095 ± 43 vs. 135 ± 5 kJ) and the exercise duration 17 times longer (60 vs. 3.5 min) than during SIE. Muscle samples were taken before and 3 h after exercise. The mRNA of upstream markers of mitochondrial biogenesis [peroxisome proliferator-activated receptor-γ coactivator-1 (PGC-1α), PGC-1α-related coactivator (PRC) and peroxisome proliferator-activated receptor δ (PPARδ)] increased to the same extent after SIE and IE (6-, 1.5- and 1.5-fold increase, respectively). Of the downstream targets of PGC-1α, mitochondrial transcription factor A (Tfam) increased only after SIE and was significantly different from that after IE (P < 0.05), whereas others increased to the same extent (pyruvate dehydrogenase kinase, PDK4) or was unchanged (nuclear respiratory factor 2, NRF2). We conclude that upstream genetic markers of mitochondrial biogenesis increase in a similar way in elite athletes after one exercise session of SIE and IE. However, since the volume and duration of work was considerably lower during SIE and since Tfam, the downstream target of PGC-1α, increased only after SIE, we conclude that SIE might be a time-efficient training strategy for highly trained individuals.

  • 149.
    Rajamäki, Niklas
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Styrketräning via ocklusion: en metod för effektivisering av styrketräning2007Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpStudent thesis
    Abstract [sv]

    Syfte och frågeställningar

    Syftet med undersökningen har varit att jämföra två olika styrketräningsmetoder med olika grader av ocklusion för träning av musculus (m.) biceps brachii med avseende på styrka och hypertrofi.

    - Vilken av de två träningsmetoderna påverkar mest effektivt biceps brachiis styrkeutveckling?

    - Vilken av de två träningsmetoderna påverkar mest effektivt biceps brachiis storlek?

    Metod

    Sju manliga försökspersoner fördelade på två grupper (tre i relaxationsgruppen, fyra i kontraktionsgruppen) fick genomgå två tester för att mäta maximal styrka i m. biceps brachii samt ett test för att mäta överarmens omkrets. Därefter fick de träna specifik bicepsträning tre gånger i veckan under fem veckor för att åter testas. Skillnaden i träning för de båda grupperna bestod av en tydlig relaxation (avslappning) en gång under varje rörelsecykel för relaxationsgruppen (relaxationen varade i ca en sekund och utfördes då hanteln var längst ner i rörelsen) medan kontraktionsgruppen ombeddes att kontrahera (spänna) muskeln under hela rörelseförloppet. För- och eftertest jämfördes mot varandra i ett beroende T-test även ökningen i träningsbelastning jämfördes mellan det andra och fjortonde passet. Därefter jämfördes förändringen mellan grupperna.

    Resultat

    Den enda signifikanta förändringen i båda träningsgrupperna för sig noterades i det funktionella testet, med en ökning av den maximala styrkan (p=0,03 för kontraktionsgruppen; p=0,03 för relaxationsgruppen). En ökning av totalbelastningen i antal kg per träningspass noterades, men ökningarna var inte signifikanta. Vid en jämförelse av träningseffekterna av relaxations- och kontraktionsträning av biceps brachii tillsammans uppnåddes statistisk signifikans såväl avseende ökning av omkrets (p=0,0136), för maximal styrka (p=0,0002) som för den totala belastningen mellan det andra och fjortonde träningspasset (p= 0,0293).

    Slutsats

    Sammanfattningsvis kan det konstateras att inga tydliga skillnader mellan träningsgrupperna kunnat urskiljas. Om resultaten för de båda träningsgrupperna sammanvägs uppnås en signifikant ökning av såväl omkrets som maximal styrka.

  • 150. Reilly, Thomas
    et al.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    The use of recovery methods post-exercise.2005In: Journal of Sports Sciences, ISSN 0264-0414, E-ISSN 1466-447X, Vol. 23, no 6, p. 619-27Article in journal (Refereed)
    Abstract [en]

    Competitive soccer engages many of the body's systems to a major extent. The musculoskeletal, nervous, immune and metabolic systems are stressed to a point where recovery strategies post-exercise become influential in preparing for the next match. Intense activity at a 7-day training camp causes participants to experience lowered concentrations of non-killer cells and T-helper cells. Two consecutive games in 24 h produce disturbances in the testosterone-cortisol ratio. When competitive schedules are congested, the recovery process should be optimized for performance capabilities to be restored to normal as soon as possible. There is evidence that glycogen stores are reduced near to depletion at the end of a soccer game and that a diet high in carbohydrates can aid recovery. Water alone is not the best means of restoring body fluids, since carbohydrate-electrolyte drinks display better intestinal absorption and reduce urine output. Some relief from muscle soreness may be achieved by means of a warm-down. Deep-water running regimens can replace conventional physical training in the days after competition. Massage, cryotherapy and alternative therapies have not been shown to be consistently effective. It is concluded that optimizing recovery post-exercise depends on a combination of factors that incorporate a consideration of individual differences and lifestyle factors. The procedures to facilitate recovery processes should start immediately the game or training finishes. Match administrators and tournament planners should consider the stressful consequences for players in periods of congested fixtures and alleviate the physiological strain as far as possible by allowing 72 h between competitive games. This frequency of competition is unlikely to be sustainable in the long term.

12345 101 - 150 of 207
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf