Gymnastik- och idrottshögskolan, GIH

The insulin-like growth factor (IGF)-IGF binding proteins (BP) and the pituitary-gonadal axes were investigated during ultra endurance exercise in 16 endurance-trained athletes (seven women). Median duration of the race was 6.3 days. Although food and drink were ad libitum, energy balance was negative. Blood samples were drawn before (PRE), at the end of (END) and 24 h after (POST24h) the race. Serum concentrations of total IGF-I (t-IGF-I) and free IGF-I (f-IGF-I) decreased by 33 (SD 38)% and 54 (19)%, respectively. The decrease in t-IGF-I appeared to be associated to the total energy deficit during the race. At END, the IGFBP-3 fragmentation and IGFBP-1 were increased but these changes did not predict changes in f-IGF-I. An increase in POST24h IGFBP-2 levels in women was the only sex difference. Testosterone was decreased by 67 (12)% in the men and estradiol became undetectable in the women without any detectable increase in LH and/or FSH. In conclusion ultra endurance exercise results in similar IGF-IGFBP responses in men and women reflecting a catabolic state. IGFBP-2 was the only exception, with increased levels in women after exercise. A concomitant decrease in gonadal hormones was not related to endocrine changes in the IGF-IGFBP axis but may be related to local changes in IGF-I expression.

Physiological and medical effects of snuff have previously been obtained either in cross-sectional studies or after snuff administration to non-tobacco users. The effects of snuff cessation after several years of daily use are unknown. 24 participants with >2 years of daily snuff-use were tested before and after >6 weeks snuff cessation (SCG). A control group (CO) of 11 snuff users kept their normal habits. Resting heart rate (HR) and blood pressure (BP) were significantly lower in SCG after snuff cessation, and body mass was increased by 1.4 ± 1.7 kg. 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-1 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. In SCG group, both HR and BP were reduced during a four-stage incremental cycling test (from 50 to 80% of VO2max) and a prolonged cycling test (60 min at 50% of VO2max). Oxygen uptake (VO2), respiratory exchange ratio, blood lactate (bLa) and blood glucose (bGlu) concentration, and rate of perceived exertion (RPE) were unchanged. In CO group, all measurements were unchanged. During the prolonged cycling test, FFA was reduced, but with 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. HR and BP during rest and submaximal exercise are reduced after cessation of regular use of snuff. Evidently, the long-time adrenergic stress on circulation is reversible.

Det är mycket vanligt att idrottare använder antiinflammatoriska läkemedel både för att behandla skador och döva smärta. Hur lämpligt är det att använda preparaten under hård träning och tävling, och vad kan medicineringen ha för konsekvenser?

Den övervägande delen av deltagarna i större multisporttävlingar drabbas av någon typ av skada som i de flesta fall är lindrig. Men det är ändå ingen tvekan om att multisport kan vara farligt. Det ställs höga krav på medicinsk personal att kunna hantera en mångfald av skador och sjukdomar.

This investigation was designed to evaluate changes in plasma and muscle levels of free amino acids during an ultra-endurance exercise and following recovery. Nine male ultra-endurance trained athletes participated in a 24-h standardized endurance trial with controlled energy intake. The participants performed 12 sessions of running, kayaking and cycling (4 x each discipline). Blood samples were collected before, during and after exercise, as well as after 28 h of recovery. Muscle biopsies were taken 1 week before the test and after exercise, as well as after 28 h of recovery. During the 24-h exercise, plasma levels of branched-chain (BCAA), essential amino acids (EAA) and glutamine fell 13%, 14% and 19% (P<0.05) respectively, whereas their concentrations in muscle were unaltered. Simultaneously, tyrosine and phenylalanine levels rose 38% and 50% (P<0.05) in the plasma and 66% and 46% (P<0.05) in muscle, respectively. After the 24-h exercise, plasma levels of BCAA were positively correlated with muscle levels of glycogen (r2=0.73, P<0.05), as was the combined concentrations of muscle tyrosine and phenylalanine with plasma creatine kinase (r2=0.55, P<0.05). Following 28-h of recovery, plasma and muscle levels of amino acids had either returned to their initial levels or were elevated. In conclusion, ultra-endurance exercise caused significant changes elevations in plasma and muscle levels of tyrosine and phenylalanine, which suggest an increase in net muscle protein breakdown during exercise. There was a reduction in plasma concentrations of EAA and glutamine during exercise, whereas no changes were detected in their muscle concentration after exercise.

Regular exercise and a physically active lifestyle have favorable effects on health. Several issues related to this theme are addressed in this report. A comment on the requirements of personalized exercise medicine and in-depth biological profiling along with the opportunities that they offer is presented. This is followed by a brief overview of the evidence for the contributions of genetic differences to the ability to benefit from regular exercise. Subsequently, studies showing that mutations in TP53 influence exercise capacity in mice and humans are succinctly described. The evidence for effects of exercise on endothelial function in health and disease also is covered. Finally, changes in cardiac and skeletal muscle in response to exercise and their implications for patients with cardiac disease are summarized. Innovative research strategies are needed to define the molecular mechanisms involved in adaptation to exercise and to translate them into useful clinical and public health applications.

På uppdrag av Försvarsmakten genomförde Militärmedicinska forskningsgruppen vid Åstandlaboratoriet vid Gymnastik- och idrottshögskolan Stockholm (GIH), en observationsstudie gällande fysiologisk/medicinsk belastning på 14 flygplatsjägare under en fältövning med beteckningen "F 17 - Flygvapenövning 2014".

Övningen var indelad i tre etapper, varav den första (c:a 42 tim) och sista (c:a 59 tim) planerades vara mer fysiskt och psykiskt krävande än den mellersta (c:a 114 tim). Registrering av hjärtfrekvens gjordes under hela övningen. Fysiologiska mätningar samt blodprov togs före och efter varje etapp samt efter c:a 12 timmars vila med sedvanliga kost efter övningens avslutande.

Beräkningar av energiomsättningen för de tre etapperna inklusive viloperioder var c:a 308, 185 respektive 369 kcal/tim, resulterande i totalt c:a 13 000, 21 100 respektive 21 600 kcal per etapp eller totalt c:a 55 700 kcal för hela övningen. De höga fysiska belastningarna i etapp ett och tre är klart högre än tidigare uppmätta data i svenska och utländska militära operationer. Vissa delar av etapp tre resulterade i fysiska belastningar som var på ungefär samma nivå som vid tävlingar i längre uthållighetsidrotter.

Den höga belastningen resulterade i stora förändringar i fysiologiska parametrar och medicinska markörer. Vissa mätningar av muskelstyrka i armar och ben liksom maximal syreupptagning försämrades. Testosteron sjönk under hela övningen kraftigt. Dessa och andra uppmätta data talar för att fysiska arbetsförmågan – i förlängningen "stridsvärdet" – blev klart försämrat under övningen.

Mätningen 12 timmar efter övningens avslut visade oväntade resultat. Den subjektiva ansträngningskänslan under standardiserat cykelarbete var klart förbättrat av 12-timmarsvilan efter övningen. Däremot var flertalet medicinska och fysiologiska värden oförändrade jämfört med värden vid testerna 12 timmar tidigare och därmed var de klart lägre än vid testet innan övningens start. Det är uppenbart att återhämtning av stridsvärdet inte kan bedömas subjektivt utan måste avgöras genom reliabla psykologiska och fysiologiska mätningar.

Undersökningen har gett underlag för fortsatta studier rörande bland annat typer av energitillskott under övning, olika strategier för snabb återhämtning samt försök att finna markörer för individuella reaktionsmönster på "stridsvärde" under långvariga militära operationer.

Den militärmedicinska forskningsgruppen vid Åstrandlaboratoriet, Gymnastik- och Idrottshögskolan, Stockholm, har som forskningsuppgift med stöd från Försvarsmakten att studera och föreslå insatser för att upprätthålla stridsvärdet för trupp under långvarigt fysiskt arbete. Forskningen har hitintills resulterat i åtta rapporter, där fysisk arbetsförmåga studerats under olika förhållanden. Föreliggande rapport sammanfattar de huvudsakliga resultaten från dessa undersökningar men omfattar också en diskussion gällande skillnader och likheter mellan kvinnors jämfört med mäns adaptation till långvarigt och tungt arbete samt ett kort avsnitt om fortsatta undersökningar, byggda på tidigare resultat.

En intressant trend i motions- och tävlingsvärlden är att extrema uthållighetsidrotter blir alltfler och dessa får dessutom alltfler utövare. Multisport (engelska Adventure Racing) är en av dessa. Tävlingarna består i allmänhet av löpning, cykling och paddling men ibland läggs också olika fysiska aktiviteter såsom repklättring, inlines och simning in i tävlingen.

Energy turnover was assessed in two conditions of mixed ultra-endurance exercise. In Study 1, energy expenditure and intake were measured in nine males in a laboratory over 24 h. In Study 2, energy expenditure was assessed in six males during an 800-km Adventure race (mean race time 152.5 h). Individual correlations between heart rate and oxygen uptake ([Vdot]O(2)) were established during pre-tests when kayaking, cycling, and running. During exercise, energy expenditure was estimated from continuous heart rate recordings. Heart rate and [Vdot]O(2) were measured regularly during fixed cycling work rates to correct energy expenditure for drift in oxygen pulse. Mean energy expenditure was 18,050 +/- 2,390 kcal (750 +/- 100 kcal . h(-1)) and 80,000 +/- 18,000 kcal (500 +/- 100 kcal . h(-1)) in Study 1 and Study 2 respectively, which is higher than previously reported. Energy intake in Study 1 was 8,450 +/- 1,160 kcal, resulting in an energy deficit of 9,590 +/- 770 kcal. Body mass decreased in Study 1 (-2.3 +/- 0.8 kg) but was unchanged in Study 2. Fat mass decreased in Study 2 (-2.3 +/- 1.5 kg). In Study 1, muscle glycogen content decreased by only 60%. Adventure racing requires a high energy expenditure, with large inter-individual variation. A large energy deficit is caused by inadequate energy intake, possibly due to suppressed appetite and gastrointestinal problems. The oxygen pulse, comparing start to 12 h of exercise and beyond, increased by 10% and 5% in Study 1 and Study 2 respectively. Hence, estimations of energy expenditure from heart rate recordings should be corrected according to this drift.

The hypothesis that ultraendurance exercise influences muscle mitochondrial function has been investigated. Athletes in ultraendurance performance performed running, kayaking, and cycling at 60% of their peak O(2) consumption for 24 h. Muscle biopsies were taken preexercise (Pre-Ex), postexercise (Post-Ex), and after 28 h of recovery (Rec). Respiration was analyzed in isolated mitochondria during state 3 (coupled to ATP synthesis) and state 4 (noncoupled respiration), with fatty acids alone [palmitoyl carnitine (PC)] or together with pyruvate (Pyr). Electron transport chain activity was measured with NADH in permeabilized mitochondria. State 3 respiration with PC increased Post-Ex by 39 and 41% (P < 0.05) when related to mitochondrial protein and to electron transport chain activity, respectively. State 3 respiration with Pyr was not changed (P > 0.05). State 4 respiration with PC increased Post-Ex but was lower than Pre-Ex at Rec (P < 0.05 vs. Pre-Ex). Mitochondrial efficiency [amount of added ADP divided by oxygen consumed during state 3 (P/O ratio)] decreased Post-Ex by 9 and 6% (P < 0.05) with PC and PC + Pyr, respectively. P/O ratio remained reduced at Rec. Muscle uncoupling protein 3, measured with Western blotting, was not changed Post-Ex but tended to decrease at Rec (P = 0.07 vs. Pre-Ex). In conclusion, extreme endurance exercise decreases mitochondrial efficiency. This will increase oxygen demand and may partly explain the observed elevation in whole body oxygen consumption during standardized exercise (+13%). The increased mitochondrial capacity for PC oxidation indicates plasticity in substrate oxidation at the mitochondrial level, which may be of advantage during prolonged exercise.

Although it is well known that endurance exercise induces oxidative stress (1) there is no evidence of deteriorated mitochondrial function after 1-2 hours intensive exercise (2). However, the effects of extreme endurance exercise on mitochondrial function and mitochondrial ROS production have not been investigated previously. Nine healthy well-trained men (age 27.1 ± 0.87 (mean ± SE), BMI 24.2 ± 0.64 and VO₂ peak 62.5 ± 1.78 ml/kg. min) performed 24 hours exercise, consisting of equal parts running, cycling and paddling. Muscle biopsies were taken from vastus lateralis pre-exercise (PreEx), immediately post-exercise (PostEx) and after 28 hours of recovery (PostEx-28). Mitochondria were isolated and mitochondrial respiration was analyzed with palmitoyl-carnitine (PC) and pyruvate (Pyr). Mitochondrial H₂O₂ release was measured with the Amplex Red-horseradish peroxide method. The reaction was initiated by addition of succinate with following addition of antimycin A (reversed electron flow). UCP3 protein expression, evaluated with western blot technique, was not changed by exercise. Both state 3 (Pyr and PC) and state 4 (PC) rates of oxygen consumption (estimated per maximal ETC-activity) were increased PostEx (+29%, +11% and +18%). State 3 remained elevated PostEx-28, whereas state 4 (Pyr) decreased below that at PreEx (-18%). Mitochondrial efficiency (P/O) decreased PostEx (Pyr -8.9%, PC -6.1%) and remained reduced PostEx-28. The relative substrate oxidation (state 3 PC/Pyr) increased after exercise PreEx: (0.71 ± 0.06 vs. PostEx (0.90 ±0.04) and (0.77 ±0.06) PostEx-28. Mitochondrial H₂O₂ release (succinate) increased dramatically after exercise (+189 ± 64%). Treatment with Antimycin A resulted in a twofold-increased rate of mitochondrial H₂O₂ release PreEx but a decreased rate in PostEx samples. The exercise-induced changes in mitochondrial ROS production was totally abolished PostEx-28. In conclusion extreme endurance exercise decreases mitochondrial efficiency and increases mitochondrial ROS production. Both of these changes would increase the oxygen demand during exercise. Relative fatty acid oxidation as measured in isolated mitochondria increased after exercise indicating that the capacity to oxidize fat is improved during prolonged exercise.

1. Mastaloudis, A., S.W. Leonard, and M.G. Traber, Oxidative stress in athletes during extreme endurance exercise. Free Radic Biol Med, 2001. 31(7): p. 911-22.

2. Tonkonogi, M., et al., Mitochondrial function and antioxidative defence in human muscle: effects of endurance training and oxidative stress. J Physiol, 2000. 528 Pt 2: p. 379-88.

Introduction

To predict endurance performance and evaluate adaption to training in endurance athletes a laboratory test for retrieving the anaerobic lactate threshold is often used. The maximal rate of oxidative metabolism that can be sustained during prolonged exercise indicates preserved homeostasis and thereby sets the upper limit for long term endurance. Exercise intensities above the anaerobic threshold require an additional input from anaerobic energy sources resulting in blood lactate accumulation and reduced time to fatigue. The threshold is therefore a reliable and powerful predictor of performance in aerobic exercise lasting approximately 40-60 min. The work rate that elicits a blood lactate of 4 mmol/l (e.g. LT4) is widely used to determine the threshold, but by using a fixed lactate concentration, flexibility to account for inter- and intra-individual differences in aerobic and anaerobic metabolism is lost. Our hypothesis was that our modified D-max method (D-maxmod) would provide a more accurate performance related value by calculating the individual anaerobic threshold (IAT).

Methods

20 males cyclists age 36 ± 5 years, weight 79.7 ± 5.8 kg, VO2max 4.4 ± 0.4 l/min performed an incremental test on a cycle ergometer for calculation of LT (D-maxmod, and LT4) at two occasions separated by 8 weeks. The test consisted of 5 minutes long stages separated by 1 min of rest were lactate was sampled. The increase in work rate was 30 W/stage starting at 100 W and ended above LT4. Short after, an incremental test to fatigue (start at LT4 power, increase 20 W/min) was performed for assessment of VO2max, calculation of maximal aerobic power (MAP) and maximal power achieved in the test (Wmax). On a separate day a 40 minutes time-trial (TT40) was performed for assessment of aerobic endurance performance. IAT D-maxmod was defined as the derivate to the exponential curve created from exponentially lactate increase, including maximal lactate concentration plotted at MAP. The increase in lactate relative to power was defined as the increase in blood lactate from the point where the exponential curve crossed the lactate baseline (See also Cheng et al. 1992 and Zhou & Weston 1997).

Results

IAT D-maxmod was calculated to 5.0 ± 0.8 mmol/l. Both D-maxmod and LT4 were highly significantly correlated with both TT40 and Wmax. Coefficients of determination were higher for D-maxmod compared to LT4 for both TT40 (r2 = 0.78 vs 0.69) and Wmax (r2 = 0.89 vs 0.64).

Conclusion

The calculated D-maxmod correlated better with performance than LT4 for parameters highly linked to performance in road- and mountain bike competitions.

References

Cheng B, Kuipers H, Snyder AC, et al. (1992). Int. J Sports Med. 13:518-22

Zhou S, Weston SB (1997). Physiol. Meas. 18: 145

Energistatus och förändring i fysiskt stridsvärde studerades i samband med en nästan 8 dygn långa grundmilitär slutövning (GMU) vid AMF-1 Berga Örlogsskolor i månadsskiftet oktober november 2013.

Totalt deltog 105 soldater i övningen, fördelat på 3 plutoner om vardera 35 soldater. En subgrupp på 24 soldater (8 kvinnor) bestående av 8 soldater från vardera pluton studerades mer ingående.

Medelhjärtfrekvensen för de 6 soldater (2 kvinnor) som hade i stort sett kompletta mätningar från den 187 timmar långa övningen, inklusive viloperioder, var 88 ± 7 slag/minut. Utifrån hjärtfrekvensdata beräknades den totala energiomsättningen till i genomsnitt 44 000 ± 6 600 kcal, vilket motsvarar 5 600 ± 840 kcal per dygn och 235 ± 35 kcal/tim. Total energiförbrukning var i genomsnitt 39 000 kcal för kvinnorna och 46 500 kcal för männen. I övrigt noterades inte några betydande skillnader mellan kvinnor och män. Däremot var det stora individuella variationer i energiutgift, vilka till ca hälften berodde på skillnader i kroppsvikt. Med hänsyn till kroppsvikt och buren vikt var energiförbrukningen ca 3,1 ± 0,23 kcal per timme per kg totalvikt. Den individuella variationen beror på skillnad i buren vikt, på olika uppgifter och på individuella fysiologiska skillnader.

Utifrån beräknat energiintag blev det totala energiunderskottet under övningen 12 000-15 000 kcal, vilket är ca 1 500-2 000 kcal per dygn. Viktminskningen under övningen var 2,9 kg för kvinnor och 3,7 kg för män. Denna viktminskning på >4 % leder troligen till försämrad uthållighetsförmåga.

Den maximala muskelstyrkan i armar och ben var i stort sett oförändrade efter övningen, liksom den beräknade maximala syreupptagningsförmågan. Däremot upplevdes ett lågintensivt cykelarbete som betydligt tyngre efter övningen. Muskeluthållighet mättes inte i denna studie.

Ett skjutprov om 5 skott i liggande på 100 m mot en tredjedelsfigur visade 64 deltagande soldater på en försämrad träffprocent från 90,5% före till 79,4 % efter övningen. Alla soldater hade minst en träff före medan 6 soldater hade alla bom efter övningen.

Slutsatsen från studien är att GMU-övningen resulterade i ett stort energiunderskott. Stridsvärdet, bedömt från skjutprovet var klart försämrat. Maximala fysiologiska parametrar var i stort sett oförändrade, medan skattad ansträngning och därmed uthållighetsförmåga, försämrades.

Denna observationsstudie av militär grundutbildning för kadetter visar mycket tydligt att förflyttning i fjällmiljö leder till stort energiunderskott, till viss del beroende på ökade energiutgifter i och med bärande av utrustning, men framför beroende på otillräckligt energiintag.

Den genomsnittliga energiförbrukningen över övningens 100 timmarna och ca 78 km förflyttning var ca 260 kcal/h, medan energiintaget endast 135 kcal/h. Även om en typ av rations (mjukkonserv) gav i genomsnitt högre energiintag än två rations av frystorkat blev det genomsnittliga energiunderskottet för samtliga rations nästan 50 %.

Mätningarna visade stora variationer mellan olika deltagare vilket dock endast delvis kan förklaras med tekniken av att bära tungt.

Skjutprov (precision) visade att stridsvärdet påverkats negativt, genom en klart försämrad träffbild efter övningen. De fysiologiska testerna visar ökad hjärtfrekvens och upplevd ansträngning på submaximala belastningar, medan de maximala nivåerna av de fysiologiska kapaciteterna kondition, muskelstyrka i hand och ben i stort sett var oförändrade.

Kommande undersökningar på motsvarande övningar bör inriktas på interventionsstudier på fördelning av utrustningsvikter, samt hur kostintaget bör förbättras för att nå ökat energiintag.

På längre sikt bör träningsmodeller för att förbättra förmågan att bära tung utrustning utvärderas.

For all athletes, it is important to adjust training plans and competition schedule according to each individual's specific traits and situation. This is crucial in team sports, where players, despite being involved in the same sport, and even on the same team, may have very different physiological capacities and, also have completed a wide variety of work in both training and match situations. A first step towards being able to carry out individualized training is to accurately measure the amount of stress (physiological burden) for each individual. The purpose of the study was to create a comprehensive picture of the physical requirements of elite handball matches, and further investigate how the relationship between work load and physical capacity impacts performance.

Heart rate measurements have since decades been used to quantify the relative work, and GPS measurement as a tool for objective values has been available for outdoor sports for about ten years, but GPS is not possible to use indoors. We have used a new technology with a similar system for indoor use called Local Positioning System (LPS) (Kinexon Precision Technologies, Münich, Germany) to record and analyze the players’ motion during games, and we have combined that technology with data from accelerometry, gyroscope and heart rate measurements.

So far, 42 handball matches have been measured and analyzed, ranging from juniors (9 games U21 men's national team) to seniors, men and women, and both in Sweden’s highest league and between national teams (Women: 8 national and 7 international games; Men: 14 national and 4 international games).

A first "result" is that the categorization of motion patterns need to be adapted to each sport. For example, some moves that should be counted as accelerations in handball are not recognized by the system, simply because it has been adapted to the pattern of motion on the much larger soccer field. This is similarly important to realize when comparing results for handball’s physiological requirements reached using other technologies. In this presentation, we will in part discuss the future technological opportunities, and in part report descriptive results, including how fast and far the players move, as well as differences between men and women, between national and international games, and between juniors and seniors.

Sjutton kvinnliga vältränade försökspersoner, åtta stycken med vana att bära tungt och nio stycken utan sådan vana, genomförde gång på löpband och mjukt underlag i hastigheterna 3 och 5 km/tim med bärvikter i ryggsäck på 20, 35 och 50 kg.Mjukt underlag i form av blå gymnastikmattor, indikerande gång i lätt terräng, ökade energiomsättningen under både hastigheterna mellan 10 och 15 %, jämfört med hårt underlag (löpband) med en grads lutning. Energiomsättningen ökade i genomsnitt lika mycket med ökad hastighet som med ökad bärvikt. Den individuella variationen vid en given bärvikt och hastighet är mycket stor. Beroende på bärvikt och hastighet kan energiomsättningen variera med 100 %. Dessa stora variationer i energiomsättning bör uppmärksammas vid beräkning av energitilldelning via kosten vid längre militära operationer.Energiomsättningen vid tyngsta belastningen – 50 kilo bärvikt och hastigheten 5 km/tim – belastade försökspersonerna på i genomsnitt 57 % av maximal syreupptagningsförmåga. I individuella fall var belastningen 72 % av maximal syreupptagningsförmåga. Dessa höga belastningar är oacceptabelt höga för transporter under längre tid och kan vara en orsak till belastningsskador.Förmågan att bära tungt sammanfaller med ökad kroppsvikt och benmuskelstyrka. Bärförmåga för mindre vikter, högst 35 kg, sammanfaller inte med någon av ovanstående faktorer. Således, för tyngre bärvikter vid förflyttningar bör selektion av soldater ske enligt de uppmätta parametrarna, medan vad gäller lättare vikter föreligger inte samma selektionskriterier.En slutsats från resultaten av denna undersökning är den ursprungliga uttagningen till tunga arbetsuppgifter inom försvaret bör genomföras med tunga arbetsbelastningar, motsvarande de i denna undersökning. I kommande rapport sammanfattas studierna på män och kvinnors bärförmåga, likheter och olikheter mellan könen, möjliga selektionskriterier samt rekommendationer med utgångspunkt från genomförda undersökningar och resultat från olika andra undersökningar.

The energy expenditure during carrying no load, 20, 35 and 50 kg at two walking speeds, 3 and 5 km/h, was studied in 36 healthy participants, 19 men (30 ± 6 yrs, 82.5 ± 7.0 kg) and 17 women (29 ± 6 yrs, 66.1 ± 8.9 kg). Anthropometric data, leg muscle strength as well as trunk muscle endurance and muscle fibre distribution of the thigh were also obtained. To load the participant a standard backpack filled with extra weight according to the carrying weight tested was used. Extra Load Index (ELI), the oxygen uptake (VO2) during total load over no-load-exercise, was used as a proxy for load carrying ability. In addition to analyzing factors of importance for the ELI values, we also conducted mediator analyzes using sex and long term carrying experience as causal variables for ELI as the outcome value. For the lowest load (20 kg), ELI20, was correlated with body mass but no other factors. Walking at 5 km/h body mass, body height, leg muscle strength and absolute VO2max were correlated to ELI35 and ELI50, but relative VO2max, trunk muscle endurance and leg muscle fibre distribution were not. Sex as causal factor was evaluated in a mediator analyses with ELI50 as outcome. ELI50 at 5 km/h differed between the sexes. The limit for acceptable body load, 40% of VO2max (according to Astrand, 1967), was nearly reached for women carrying 35 kg (39%) and surpassed at 50 kg at 3 km/h, and for men carrying 50 kg at 5 km/h. This difference was only mediated by difference in body mass. Neither muscle fibre distribution, leg muscle strength, trunk muscle endurance and body height nor did absolute or relative VO2max explain the difference. Participants with long term experience of heavy load carrying had significant lower ELI20 and ELI50 values than those with minor or non-experience, but none of the above studied factors could explain this difference. The study showed that body mass and experience of carrying heavy loads are important factors for the ability to carry heavy loads.

INTRODUCTION: The ability to carry heavy loads is an important and necessary task during numerous outdoor activities and especially in military operations. The aim of this study was to investigate factors associated with load-carrying ability in men and women with and without extensive load-carrying experience.

MATERIALS AND METHODS: The energy expenditure during carrying no load, 20, 35, and 50 kg at 2 walking speeds, 3 and 5 km h-1, was studied in 36 healthy participants, 19 men (30 ± 6 years, 82.5 ± 7.0 kg) and 17 women (29 ± 6 years, 66.1 ± 8.9 kg), experienced (>5 years) in carrying heavy loads (n = 16, 8 women) or with minor or no such experience (n = 20, 9 women). A standard backpack filled with weights to according carry load was used during the walks. Anthropometric data, leg muscle strength, as well as trunk muscle endurance and muscle fiber distribution of the thigh, were also obtained. Extra Load Index (ELI)-the oxygen uptake (VO2) during total load over unloaded walking-was used as a proxy for load-carrying ability at 20, 35, and 50 kg (ELI20, ELI35, and ELI50, respectively). In addition to analyzing factors of importance for the ELI values, we also conducted mediator analyses using sex and long-term carrying experience as causal variables for ELI as the outcome value. The study was approved by the Regional Ethics Committee in Stockholm, Sweden.

RESULTS: For the lowest load (20 kg), ELI20, was correlated with body mass but no other factors. Walking with 35 and 50 kg load at 5 km h-1 body mass, body height, leg muscle strength, and absolute VO2max were correlated, while relative VO2max, trunk muscle endurance, and leg muscle fiber distribution were not correlated to ELI35 and ELI50.ELI50 at 5 km h-1 differed between the sexes. This difference was only mediated by the difference in body mass. Neither muscle fiber distribution, leg muscle strength, trunk muscle endurance, and body height nor did absolute or relative VO2max explain the difference.Participants with long-term experience of heavy load carrying had significant lower ELI20 and ELI50 values than those with minor or no experience, but none of the above studied factors could explain this difference.

CONCLUSION: The study showed that body mass, without sex differences, and experience of carrying heavy loads are the dominant factors for the ability to carry heavy loads. Even though the effect of experience alludes to the need for extensive carrying training, no causality can be proven. Load carry training intervention studies is suggested for future investigations.

Nitton manliga vältränade försökspersoner, 9 st med vana att bära tungt och 10 st utan sådan vana, genomförde gång på mjukt underlag i hastigheterna 3 och 5 km/tim med bärvikter i ryggsäck på 20, 35 och 50 kg.

Energiomsättningen ökade i genomsnitt lika mycket med ökad hastighet som med ökad bärvikt. Mjukt underlag, indikerande gång i lätt terräng, ökade energiomsättningen under både hastigheterna med c:a 20 %, jämfört med hårtunderlag (löpband). Den individuella variationen vid en given bärvikt och hastighet är mycket stor. Beroende på bärvikt och hastighet kan energiomsättningen variera med 100%.  Dessa stora variationer i energiomsättning bör uppmärksammas vid beräkning av energitilldelning via kosten vid längre militära operationer.

Energiomsättningen vid tyngsta belastningen – 50 kilo bärvikt och hastigheten 5 km/tim – belastade försökspersonerna på i genomsnitt 44 % av maximal syreupptagningsförmåga. I individuella fall var belastningen 60%. Dessa höga belastningar är oacceptabelt höga för transporter under längre tid och kan vara en orsak till belastningsskador.

Förmågan att bära tungt sammanfaller med ökad kroppsstorlek – både längd och vikt – ålder, maximal syreupptagningsförmåga mätt i L/min men inte i ml/min och kg kroppsvikt, benmuskelstyrka men inte bålmuskelstyrka samt andelen muskelfibrer i lårmuskeln av typ 1. Flera men inte alla av dessa förmågor kan säkert till viss del tränas upp. Bärförmåga för mindre vikter, högst 35 kg, sammanfaller inte med några av ovanstående faktorer, bortsett från ålder. Således, för tyngre bärvikter vid förflyttningar bör selektion av soldater ske enligt de uppmätta parametrarna, medan vad gäller lättare vikter föreligger inte samma selektionkriterier.

En slutsats från resultaten av denna undersökning är den ursprungliga uttagningen till tunga arbetsuppgifter inom försvaret bör genomföras med tunga arbetsbelastningar, motsvarande de i denna undersökning. Avsikten i fortsättningen av denna undersökningsserie är att fastställa ny testmetodik och procedur för denna selektion samt genomföra tester på kvinnor.

Energistatus, muskelfysiologiska data och fysiskt stridsvärde studerades före och efter en 8 dygn långa grundmilitär slutövning (GMU) vid AMF-1 Berga Örlogsskolor i månadsskiftet oktober november 2013.

Totalt deltog 105 soldater i övningen, fördelat på 3 plutoner om vardera 35 soldater. En subgrupp på 24 soldater (8 kvinnor) bestående av 8 soldater från vardera pluton studerades mer ingående.

Medelhjärtfrekvensen för de 6 soldater (2 kvinnor) som hade i stort sett kompletta mätningar från den 187 timmar långa övningen, inklusive viloperioder, var 88 ± 7 slag/minut. Utifrån hjärtfrekvensdata beräknades den totala energiomsättningen till i genomsnitt 44 000 ± 6 600 kcal, vilket motsvarar 5 600 ± 840 kcal per dygn och 235 ± 35 kcal/tim. Total energiförbrukning var i genomsnitt 39 000 kcal för kvinnorna och 46 500 kcal för männen. I övrigt noterades inte några betydande skillnader mellan kvinnor och män. Däremot var det stora individuella variationer i energiutgift, vilka till ca hälften berodde på skillnader i kroppsvikt. Med hänsyn till kroppsvikt och buren vikt var energiförbrukningen ca 3,1 ± 0,23 kcal per timme per kg totalvikt. Den individuella variationen beror på skillnad i buren vikt, på olika uppgifter och på individuella fysiologiska skillnader.

Utifrån beräknat energiintag blev det totala energiunderskottet under övningen 12 000-15 000 kcal, vilket är ca 1 500-2 000 kcal per dygn. Viktminskningen under övningen var 2,9 kg för kvinnor och 3,7 kg för män. Denna viktminskning på >4 % leder troligen till försämrad uthållighetsförmåga.

Den maximala muskelstyrkan i armar och ben var i stort sett oförändrade efter övningen, liksom den beräknade maximala syreupptagningsförmågan. Däremot upplevdes ett lågintensivt cykelarbete som betydligt tyngre efter övningen. Muskeluthållighet mättes inte i denna studie.

Ett skjutprov om 5 skott i liggande på 100 m mot en tredjedelsfigur visade 64 deltagande soldater på en försämrad träffprocent från 90,5% före till 79,4 % efter övningen. Alla soldater hade minst en träff före medan 6 soldater hade alla bom efter övningen.

Slutsatsen från studien är att GMU-övningen resulterade i ett stort energiunderskott. Stridsvärdet, bedömt från skjutprovet var klart försämrat. Maximala fysiologiska parametrar var i stort sett oförändrade, medan skattad ansträngning och därmed uthållighetsförmåga, försämrades.

Effective practices to improve skeletal muscle fatigue resistance are crucial for athletes as well as patients with dysfunctional muscles. To this end, it is important to identify the cellular signaling pathway that triggers mitochondrial biogenesis and thereby increases oxidative capacity and fatigue resistance in skeletal muscle fibers. Here, we test the hypothesis that the stress induced in skeletal muscle fibers by endurance exercise causes a reduction in the association of FK506-binding protein 12 (FKBP12) with ryanodine receptor 1 (RYR1). This will result in a mild Ca²⁺ leak from the sarcoplasmic reticulum (SR), which could trigger mitochondrial biogenesis and improved fatigue resistance. After giving mice access to an in-cage running wheel for three weeks, we observed decreased FKBP12 association to RYR1, increased baseline [Ca²⁺]_i, and signaling associated with greater mitochondrial biogenesis in muscle, including PGC1α1. After six weeks of voluntary running, FKBP12 association is normalized, baseline [Ca²⁺]_i returned to values below that of nonrunning controls, and signaling for increased mitochondrial biogenesis was no longer present. The adaptations toward improved endurance exercise performance that were observed with training could be mimicked by pharmacological agents that destabilize RYR1 and thereby induce a modest Ca²⁺ leak. We conclude that a mild RYR1 SR Ca²⁺ leak is a key trigger for the signaling pathway that increases muscle fatigue resistance.

Introduction

Unilateral (UL) training as an alternative method for developing athletic performance are not well studied (1, 2). The purpose is to examine the effects of bilateral (BL) versus UL complex training combined with high intensity interval training (HIIT) on bilateral deficit (BLD), power deficit, maximal strength, jumping ability, straight sprint, change of direction sprint (CODS), repeated sprint ability (RSA) and specific endurance in elite handball players.

Methods

18 male and 12 female elite handball players were assigned to a BL (n=10) or UL (n=20) complex training program. In addition both groups trained HIIT twice a week. Training volume, intensity and exercise motions were similar between the groups. Tests included 1RM UL and BL Smith machine squat, UL and BL counter movement jump (CMJ), squat jump (SJ), modified T-test, straight sprint (5, 10, 20 and 30 m), repeated shuttle sprint ability (RSSA) and Yo-Yo Intermittent Recovery test (YYIR) before and after 6 weeks of training.

Results

Pooled data from both groups showed significant (p <0.01) improvements in maximal UL and BL strength, UL CMJ dominant leg, CODS and YYIR test, and an unwanted increase in the BLD and power deficit.

There were no significant differences training groups in any of the tests. However, only the UL group significantly improved RSA_total pre- to post testing (p < 0.01).

Discussion

Results indicate that this type of training is a relevant model for pre-season training of maximal strength, power and functional endurance. Despite the lack of differences between groups, UL training can be safer than BL training because of less absolute load.

1) Jones MT, Ambeganokar JP, Nindl BC, Smith JA, Headley SA. (2012). J Strength Cond Res, 26(4), 1094-100

2) McCurdy K, Langford G, Doscher MW, Wiley LP, Mallard KG. (2005). J Strength Cond Res, 19(1), 9-15

The impact of a 24h ultra-endurance exercise bout on systemic and local muscle inflammatory reactions was investigated in nine experienced athletes. Blood and muscle biopsies were collected before (PRE), immediately after the exercise (POST) and after 28h of recovery (POST28). Circulating blood levels of leukocytes, CK, CRP and selected inflammatory cytokines were assessed together with the evaluation of the occurrence of inflammatory cells (CD3(+), CD8(+), CD68(+)) and the expression of major histocompatibility complex class-I (MHC class-I) in skeletal muscle. An extensive inflammatory cell infiltration occurred in all athletes and the number of CD3(+), CD8(+) and CD 68(+) cells were 2-3 fold higher at POST28 compared to PRE (P<0.05). The inflammatory cell infiltration was associated with a significant increase in the expression of MHC class-I in muscle fibers. There was a significant increase in blood leukocyte count, IL-6, IL-8, CRP and CK at POST. At POST28 total leukocytes, IL-6 and CK had declined, whereas IL-8 and CRP continued to increase. Increases in IL-1β and TNF-α were not significant. There were no significant associations between the magnitude of the systemic and local muscle inflammatory reactions. Signs of muscle degenerative and regenerative events were observed in all athletes with various degrees of severity and were not affected by the ultra-endurance exercise bout. In conclusion, a low-intensity but very prolonged single endurance exercise bout can generate a strong inflammatory cell infiltration in skeletal muscle of well-trained experienced ultra-endurance athletes, and the amplitude of the local reaction is not proportional to the systemic inflammatory response.

This talk will focus on the major nutritional and physiological factors that influence ultra-endurance exercise performance in both recreational and elite athletes.

Empirical observations show that athletes who have been engaged in ultra-endurance sports for several years have a large advantage compared to novices in the sport. It depends of course in part on the fact that they are more experienced, but even athletes from traditional endurance sports with a documented higher aerobic capacity (i.e., higher VO2max) have difficulties to keep up with ultra-endurance specialists when exercise duration exceeds three or four hours. This indicates that fatigue and performance in ultra-endurance exercise is determined by (in part) other factors compared to traditional endurance sports.

Ultra-endurance sports vary in form and duration, such as running or adventure racing (AR) from 6 h to more than 6 days, but are no matter the nature of the specific competition still in many aspects extreme sports.

The athletes do not generally need to perform at high maximum speeds, but the energy expenditure is extremely high. The total energy expenditure for a 24-h AR is approximately 18-20 000 kcal, which is almost 10 times more than normal basal metabolism (Enqvist et al. 2010). One reason for fatigue is that the energy deficit is substantial, also the profile of amino acids in blood and muscle change during races (Borgenvik et al. 2012), possibly contributing to the central fatigue that has been described in other studies.

As for the physiological factors, our research group and collaborators have investigated many aspects of the versatile physiological adaptation to ultra-endurance exercise, such as circulatory adaptations and cardiac fatigue (Mattsson 2011, Mattsson et al. 2010, 2011) muscular damage (Wichardt et al 2011, Marklund et al 2013), hormonal status (Berg et al 2008), and immunological response (Wallberg et al 2011).

The effect of sleep deprivation on both mental and physiological functions during the races must also be included in the total complex of factors limiting performance.

Boken Idrott och hjärtat beskriver de positiva effekterna av träning och fysisk aktivitet men tar också upp risker förenade med högintensiv aktivitet. Boken ger en god inblick i de grundläggande förändringarna i hjärtats arbete vid träning, på motions- och elitnivå.


Idrott och hjärtat är uppbyggd i tre delar: ”Det (troligen) friska hjärtat”, ”Det sjuka hjärtat” samt den tredje delen ”Praktiska tillämpningar” vilken beskriver dels undersökningstekniker och utredningsgång, viktiga och vanliga differentialdiagnoser och symtom, allt relaterat till hjärta och idrott.


Idrott och hjärtat riktar sig till lagläkare och andra idrottsmedicinskt engagerade, till idrottsintresserade specialister inom kardiologi, internmedicin, klinisk fysiologi och allmänmedicin samt till specialintresserade sjuksköterskor och fysioterapeuter.

Vilka konditionstestvärden har elitspelare i fotboll, ishockey och basket? Och hur tränar man effektivast sinkondition om man är bollidrottare? Mikael Mattson, doktor i fysiologi vid GIH, reder ut begreppen.

Det vore ju underbart om det fungarade! Du har på dig ett armband som talar om hur mycket du tränat, hur mycket du behöver äta, hur lång återhämtningen är och hur länge du behöver sova för att vara på topp. Om du bara lyssnar på klockan blir allt perfekt.

Tyvärr kan man inte använda dagens wearables så. De är helt enkelt för dåliga. Man får värden och siffror, men de är långt ifrån sanna eller säkra.

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.

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.

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.

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.

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".

Att vara elitidrottare idag och kunna konkurrera med de bästa innebär att många gånger balansera på gränsen för vad ens kropp och psyke klarar av att hantera. I det sammanhanget är en genomtänkt tränings- och tävlingsplanering ett måste för att man ska lyckas hålla sig på rätt sida om gränsen och också få en positiv prestationsutveckling. Och oavsett om träningen bedrivs med inriktning mot tävlingsprestation eller på motionsnivå för hälsoeffekter gäller följande: träningen är effektiv om den ger största möjliga resultat med minsta möjliga insats, i form av till exempel tidsåtgång och energiutgift. Det är därför viktigt både ur hälso- och prestationsaspekt att kunskap om träningsplanering bygger på vetenskap och erfarenhetsbaserad kompetens.

I svensk litteratur har det under lång tid saknats en mer omfattande och heltäckande bok om tränings- och tävlingsplanering. Det finns böcker som innehåller kortare avsnitt och kapitel på detta tema men ingen som tar ett helhetsgrepp. Denna bok råder nu bot på denna brist. Boken är ett resultat av ett samarbete mellan Riksidrottsförbundet och SISU Idrottsböcker där ambitionen har varit att ta fram en kunskapsöversikt på det rådande forskningsläget och presentera det på ett lättförståeligt sätt för landets många tränare och aktiva på olika nivåer. Som en del i samarbetet har resurspersoner från Riksidrottsförbundet bidragit med texter i områdena idrottsmedicin, idrottsnutrition och idrottspsykologi, detta för att ta ett helhetsgrepp på området.

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.