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  • 1.
    Holm, Lars
    et al.
    Institute of Sports Medicine and Department of Orthopedic Surgery M, Bispebjerg Hospital, Copenhagen, Denmark.
    Dideriksen, Kasper
    Institute of Sports Medicine and Department of Orthopedic Surgery M, Bispebjerg Hospital, Copenhagen, Denmark.
    Nielsen, Rie H
    Institute of Sports Medicine and Department of Orthopedic Surgery M, Bispebjerg Hospital, Copenhagen, Denmark.
    Doessing, Simon
    Institute of Sports Medicine and Department of Orthopedic Surgery M, Bispebjerg Hospital, Copenhagen, Denmark.
    Bechshoeft, Rasmus L
    Institute of Sports Medicine and Department of Orthopedic Surgery M, Bispebjerg Hospital, Copenhagen, Denmark.
    Højfeldt, Grith
    Institute of Sports Medicine and Department of Orthopedic Surgery M, Bispebjerg Hospital, Copenhagen, Denmark.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp. Karolinska institutet.
    Reitelseder, Søren
    Institute of Sports Medicine and Department of Orthopedic Surgery M, Bispebjerg Hospital, Copenhagen, Denmark.
    van Hall, Gerrit
    University of Copenhagen, Denmark.
    An exploration of the methods to determine the protein-specific synthesis and breakdown rates in vivo in humans.2019Inngår i: Physiological Reports, E-ISSN 2051-817X, Vol. 7, nr 17, artikkel-id e14143Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present study explores the methods to determine human in vivo protein-specific myofibrillar and collagenous connective tissue protein fractional synthesis and breakdown rates. We found that in human myofibrillar proteins, the protein-bound tracer disappearance method to determine the protein fractional breakdown rate (FBR) (via 2 H2 O ingestion, endogenous labeling of 2 H-alanine that is incorporated into proteins, and FBR quantified by its disappearance from these proteins) has a comparable intrasubject reproducibility (range: 0.09-53.5%) as the established direct-essential amino acid, here L-ring-13 C6 -phenylalanine, incorporation method to determine the muscle protein fractional synthesis rate (FSR) (range: 2.8-56.2%). Further, the determination of the protein breakdown in a protein structure with complex post-translational processing and maturation, exemplified by human tendon tissue, was not achieved in this experimentation, but more investigation is encouraged to reveal the possibility. Finally, we found that muscle protein FBR measured with an essential amino acid tracer prelabeling is inappropriate presumably because of significant and prolonged intracellular recycling, which also may become a significant limitation for determination of the myofibrillar FSR when repeated infusion trials are completed in the same participants.

  • 2.
    Edman, Sebastian
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Söderlund, Karin
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Apro, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    mTORC1 Signaling in Individual Human Muscle Fibers Following Resistance Exercise in Combination With Intake of Essential Amino Acids2019Inngår i: Frontiers in nutrition, ISSN 2296-861X, Vol. 6, artikkel-id 96Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Human muscles contain a mixture of type I and type II fibers with different contractile and metabolic properties. Little is presently known about the effect of anabolic stimuli, in particular nutrition, on the molecular responses of these different fiber types. Here, we examine the effect of resistance exercise in combination with intake of essential amino acids (EAA) on mTORC1 signaling in individual type I and type II human muscle fibers. Five strength-trained men performed two sessions of heavy leg press exercise. During exercise and recovery, the subjects ingested an aqueous solution of EAA (290 mg/kg) or flavored water (placebo). Muscle biopsies were taken from the vastus lateralis before and 90 min after exercise. The biopsies were freeze-dried and single fibers dissected out and weighed (range 0.95-8.1 mu g). The fibers were homogenized individually and identified as type I or II by incubation with antibodies against the different isoforms of myosin. They were also analyzed for both the levels of protein as well as phosphorylation of proteins in the mTORC1 pathway using Western blotting. The levels of the S6K1 and eEF2 proteins were similar to 50% higher in type II than in type I fibers (P < 0.05), but no difference was found between fiber types with respect to the level of mTOR protein. Resistance exercise led to non-significant increases (2-3-fold) in mTOR and S6K1 phosphorylation as well as a 50% decrease (P < 0.05) in eEF2 phosphorylation in both fiber types. Intake of EAA caused a 2 and 6-fold higher (P < 0.05) elevation of mTOR and S6K1 phosphorylation, respectively, in both type I and type II fibers compared to placebo, with no effect on phosphorylation of eEF2. In conclusion, protein levels of S6K1 and eEF2 were significantly higher in type II than type I fibers suggesting higher capacity of the mTOR pathway in type II fibers. Ingestion of EAA enhanced the effect of resistance exercise on phosphorylation of mTOR and S6K1 in both fiber types, but with considerable variation between single fibers of both types.

  • 3.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    ACSM Annual Meeting: Två dagar med fokus på muskelhypertrofi/atrofi2018Inngår i: Idrottsmedicin, ISSN 2001-3302, Vol. 37, nr 3, s. 29-31Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 4.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Effekt av kombinerad styrke- och konditionsträning2018Inngår i: Idrottsmedicin, ISSN 2001-3302, Vol. 37, nr 3, s. 8-9Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [sv]

    Det finns teorier om att kombinerad konditions- och styrketräning hämmar styrkeutvecklingen jämfört med enbart styrketräning. För att ta reda på om det stämmer genomfördes studier där cykling kombinerades med styrketräning.

  • 5.
    Lilja, Mats
    et al.
    Karolinska Institutet.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Mandić, Mirko
    Karolinska Institutet.
    Gustafsson, Thomas
    Karolinska Institutet.
    Lundberg, Tommy R.
    Karolinska Institutet.
    High versus Low doses of Anti-inflammatory Drugs Do Not Differentially Affect Muscle Molecular Response to Acute Resistance Exercise: 2008 Board #269 May 31 2:00 PM - 3:30 PM.2018Inngår i: Medicine & Science in Sports & Exercise. 2018 Supplement 1, Vol. 50, p488-488, 2018, Vol. 50, s. 488-488Konferansepaper (Annet vitenskapelig)
  • 6.
    Andersson, Eva A
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet. Karolinska institutet.
    Frank, Per
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet. Karolinska institutet.
    Pontén, Marjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    Ekblom, Maria
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet. Karolinska institutet.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Sahlin, Kent
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Improving Strength, Power, Muscle Aerobic Capacity, and Glucose Tolerance through Short-term Progressive Strength Training Among Elderly People.2017Inngår i: Journal of Visualized Experiments, ISSN 1940-087X, E-ISSN 1940-087X, nr 125Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This protocol describes the simultaneous use of a broad span of methods to examine muscle aerobic capacity, glucose tolerance, strength, and power in elderly people performing short-term resistance training (RET). Supervised progressive resistance training for 1 h three times a week over 8 weeks was performed by RET participants (71±1 years, range 65-80). Compared to a control group without training, the RET showed improvements on the measures used to indicate strength, power, glucose tolerance, and several parameters of muscle aerobic capacity. Strength training was performed in a gym with only robust fitness equipment. An isokinetic dynamometer for knee extensor strength permitted the measurement of concentric, eccentric, and static strength, which increased for the RET group (8-12% post- versus pre-test). The power (rate of force development, RFD) at the initial 0-30 ms also showed an increase for the RET group (52%). A glucose tolerance test with frequent blood glucose measurements showed improvements only for the RET group in terms of blood glucose values after 2 h (14%) and the area under the curve (21%). The blood lipid profile also improved (8%). From muscle biopsy samples prepared using histochemistry, the amount of fiber type IIa increased, and a trend towards a decrease in IIx in the RET group reflected a change to a more oxidative profile in terms of fiber composition. Western blot (to determine the protein content related to the signaling for muscle protein synthesis) showed a rise of 69% in both Akt and mTOR in the RET group; this also showed an increase in mitochondrial proteins for OXPHOS complex II and citrate synthase (both ~30%) and for complex IV (90%), in only the RET group. We demonstrate that this type of progressive resistance training offers various improvements (e.g., strength, power, aerobic capacity, glucose tolerance, and plasma lipid profile).

  • 7.
    Moberg, Marcus
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    Hendo, Gina
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    Jakobsson, Madelene
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    Mattsson, C Mikael
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Ekblom-Bak, Elin
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Flockhart, Mikael
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Forskningsgruppen Mitokondriell funktion och metabolisk kontroll.
    Pontén, Marjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Söderlund, Karin
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    Increased autophagy signaling but not proteasome activity in human skeletal muscle after prolonged low-intensity exercise with negative energy balance2017Inngår i: Physiological Reports, E-ISSN 2051-817X, Vol. 5, nr 23, artikkel-id e13518Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Little is known about the molecular regulation of skeletal muscle protein turnover during exercise in field conditions where energy is intake inadequate. Here, 17 male and 7 female soldiers performed an 8 day long field based military operation. Vastus lateralis muscle biopsies, in which autophagy, the ubiquitin-proteasome system and the mTORC1 signaling pathway where studied, were collected before and after the operation. The 187 h long operation resulted in a 15% and 29% negative energy balance as well as a 4.1% and 4.6% loss of body mass in women and men respectively. After the operation protein levels of ULK1 as well as the phosphorylation of ULK1Ser317 and ULK1Ser555 had increased by 11%, 39% and 13%, respectively, and this was supported by a 17% increased phosphorylation of AMPKThr172 (P<0.05). The LC3b-I/II ratio was 3-fold higher after compared to before the operation (P<0.05), whereas protein levels of p62/SQSTM1 were unchanged. The β1, β2, and β5 activity of the proteasome and protein levels of MAFbx did not change, while levels of MuRF-1 were slightly reduced (6%, P<0.05). Protein levels and phosphorylation status of key components in the mTORC1 signaling pathway remained at basal levels after the operation. Muscle levels of glycogen decreased from 269±12 to 181±9 mmol ∙ kg dry muscle-1 after the exercise period (P<0.05). In conclusion, the 8 days of field based exercise resulted in induction of autophagy without any increase in proteasome activity or protein ubiquitination. Simultaneously, the regulation of protein synthesis through the mTORC1 signaling pathway was maintained.

  • 8.
    Moberg, Marcus
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Hendo, Gina
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Jakobsson, Madeleine
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Mattsson, C. Mikael
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    Ekblom Bak, Elin
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    Flockhart, Mikael
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Pontén, Marjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Söderlund, Karin
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    Increased autophagy signalling but not proteasome activity in human skeletal muscle after prolonged low-intensity exercise with negative energy balance2017Inngår i: ICSPP Abstracts: Journal of Science and Medicine in Sport, Volume 20, Supplement 2, November 2017, Pages S166, 2017, Vol. 20, nr Supplement 2, s. S166-, artikkel-id 287Konferansepaper (Annet vitenskapelig)
  • 9.
    Rundqvist, Håkan Claes
    et al.
    Karolinska Institutet .
    Esbjörnsson, Mona
    Karolinska Institutet .
    Rooyackers, Olav
    Huddinge University Hospital .
    Osterlund, Ted
    Karolinska Institutet.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Apró, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Jansson, Eva
    Karolinska Institutet .
    Influence of nutrient ingestion on amino acid transporters and protein synthesis in human skeletal muscle after sprint exercise2017Inngår i: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 123, nr 6, s. 1501-1515Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nutrient ingestion is known to increase the exercise-induced stimulation of muscle protein synthesis following resistance exercise. Less is known about the effect of nutrients on muscle protein synthesis following sprint exercise. At two occasions separated by one month, twelve healthy subjects performed three 30-s sprints with 20-min rest between bouts. In randomized order, they consumed a drink with essential amino acids and maltodextrin (nutrient) or flavored water (placebo). Muscle biopsies were obtained 80 and 200 min after the last sprint and blood samples were taken repeatedly during the experiment. Fractional synthetic rate (FSR) was measured by continuous infusion of L-[(2)H5]-phenylalanine up to 200 min postexercise. The mRNA and protein expression of SNAT2 were both 1.4-fold higher (P < 0.05) after nutrient intake compared to placebo at 200 min postexercise. Phosphorylated Akt, mTOR and p70S6k was 1.7- to 3.6-fold higher (P<0.01) 80 min after the last sprint with nutrient ingestion as compared to placebo. In addition, FSR was higher (P<0.05) with nutrients when plasma phenylalanine (FSRplasma) was used as a precursor, but not when intracellular phenylalanine (FSRmuscle) was used. Significant correlations were also found between FSRplasma on the one hand and plasma leucine and serum insulin on the other hand in the nutrient condition. The results show that nutrient ingestion induces the expression of the amino acid transporter SNAT2, stimulates Akt/mTOR signaling and most likely the rate of muscle protein synthesis following sprint exercise.

  • 10.
    Moberg, Marcus
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Apró, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    Gerrit, van Hall
    Holmberg, Hans-Christer
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Activation of mTORC1 by leucine is potentiated by branched chain amino acids and even more so by essential amino acids following resistance exercise2016Inngår i: American Journal of Physiology - Cell Physiology, ISSN 0363-6143, E-ISSN 1522-1563, Vol. 310, nr 11, s. C874-C884Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 11. Rundqvist, Håkan C
    et al.
    Esbjörnsson, Mona
    Rooyackers, Olav
    Apro, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Österlund, Ted
    Jansson, Eva
    Amino Acid Transport after Sprint Exercise and Oral Amino Acids: 90 Board #6 June 1, 92016Inngår i: Medicine & Science in Sports & Exercise: Volume 48(5S) Supplement 1, May 2016, p 5, 2016, Vol. 48, nr 5 Suppl 1, s. 5-Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    PURPOSE: To study if oral ingestion of essential amino acids (oral EAA) increases the amino acid transporter SNAT2, Akt/mTOR signaling and muscle protein synthesis (MPS) after sprint exercise.

    METHODS: 12 healthy subjects performed three 30-s sprints with 20 minutes rest in between. Subjects consumed EAA + maltodextrin solution or flavoured water (placebo) during the sprint exercise up to 15 min after the last sprint in a randomized order with one month interval. In vivo MPS rate was measured using a stable isotope technique. Subject received a stable isotope of phenylalanine (D5-phenylalanine) to label the precursor pool for protein synthesis. Continuous infusion started before the first sprint and was ended 200 min after the last sprint. Two post exercise biopsies (vastus lateralis) were obtained 80 min and 200 min after last sprint. The amount of labelled phenylalanine incorporated into muscle protein over these 2 hours represents the in vivo MPS rate and was expressed as fractional synthesis rate (FSR %) calculated by dividing amount of labelled phenylalanine incorporated during these 2 hours by the amount in the free amino acid (precursor) plasma pool. Biopsies were also analyzed for Akt/mTOR signaling and SNAT2 amino acid transporter by Western blot and for SNAT2 gene expression by real-time PCR. Blood samples were analyzed for amino acids, glucose, lactate, and insulin. Four subjects, involuntary vomiting after exercise during EAA condition, showed a minor increase in plasma leucine and were presented separately.

    RESULTS: Non-vomiting subjects (n=8): The expression of the amino acid transporter SNAT2 was higher both at the protein (P<0.05) and the mRNA (P<0.001) level after EEA than after placebo. Fold increase for phosphorylated Akt, mTOR and p70 was 1.7-3.6 (P<0.01 - P<0.001) comparing EAA with placebo. FSR % after EEA was increased by 25 % (P=0.02) compared to placebo. None of these variables were significantly increased in the subjects who vomited.

    CONCLUSION: Oral EAA increased MPS after sprint exercise. Enhanced capacity for amino acid transport and subsequent enhanced Akt/mTOR signaling are suggested to mediate the increased MPS.

  • 12.
    Apró, William
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Holmberg, Hans-Christer
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Amino Acid-induced S6K1 Activity In Human Skeletal Muscle Is Mediated By Increased mTor/Rheb Interaction: 128 June 1, 11: 15 AM - 11: 30 AM.2016Inngår i: Medicine And Science In Sports And Exercise 2016 May; Vol. 48 (5S Suppl 1), pp. 17., 2016, Vol. 48, nr 5S Suppl 1, s. 17-17Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Cell culture studies have shown that amino acids activate mTORC1 signaling by increasing the interaction between mTOR and its essential activator Rheb. However, the existence of this mechanism in human skeletal muscle remains to be determined.

    PURPOSE: To determine if increased mTORC1 signaling in response to amino acids in human skeletal muscle is due to an increased interaction between mTOR and Rheb.

    METHODS: Eight well trained men performed resistance exercise on two separate occasions. In connection with the exercise, subjects were supplemented with flavored water (Pla) and essential amino acids (EAA) in a double-blind, randomized cross-over design. Muscle biopsies were taken in the vastus lateralis muscle before, immediately after and 90 and 180 min post exercise. Activity of the mTORC1 pathway was assessed by a radiolabeled in-vitro kinase assay for its immediate downstream target S6K1. Protein-protein interactions were determined by western blot following co-immunoprecipitation of mTOR with Rheb. Co-immunoprecipitation was performed on pooled muscle samples from three of the eight subjects.

    RESULTS: Activity of S6K1 remained unchanged immediately after exercise in both trials. However, at 90 min post exercise, S6K1 activity increased by approximately 2- and 8-fold (p<0.05) from baseline the Pla and EAA trials, respectively. At the 180 min time point, S6K1 activity remained elevated in both trials being approx. 3-fold higher in the Pla trial and 5-fold higher (p<0.05) in the EAA trial. The fold-change in mTOR and Rheb interaction largely resembled the activity pattern of S6K1 in both trials; in the Pla trial the fold-change was 0.9, 1.3 and 1.4 while in the EAA trial the fold-change was 1.6, 2.9 and 1.9 immediately after, 90 min after and 180 min after exercise, respectively.

    CONCLUSIONS: The large increase in S6K1 activity following EAA intake appears to be mediated by an increased interaction between mTOR and its proximal activator Rheb. This is the first time this mechanism has been demonstrated in human skeletal muscle.

  • 13.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Effects of exercise and amino acid intake on mechanisms regulating protein synthesis and breakdown in human muscle2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Skeletal muscle adapts differently to specific modes of exercise, where resistance training results in muscle growth and endurance training induces mitochondrial biogenesis. These are results of molecular events that occur after each exercise session, increasing the expression of specific genes and the rate of both synthesis and breakdown of protein. The rate of protein synthesis is controlled by the mTORC1 signaling pathway, which is potently stimulated by resistance exercise and amino acid, and their combined effect is needed for muscle growth. The essential amino acids (EAA) are responsible for the stimulation of protein synthesis and here leucine has been attributed specific attention, but its particular role among the EAA, and the involvement of the other branched-chain amino acids (BCAA) is unclear. Endurance exercise activates the protein AMPK which, in animal models, has been shown to inhibit mTORC1 signaling and protein synthesis.  Suggesting that concurrent endurance and resistance exercise could restrain muscle growth, but it is unknown if this mechanism is relevant in exercising human muscle. Little is known about the regulation of protein breakdown and although much attention has been given the proteins MuRF-1 and MAFbx which target proteins for degradation, their role requires further investigation. The aim of thesis was to address the mentioned uncertainties by examining how different modes of exercise and amino acids affect mTORC1 signaling, protein synthesis and markers of protein breakdown in human muscle.

    In study I, the influence of high intensity endurance exercise on subsequent resistance exercised induced mTORC1 signaling was examined. Despite robust activation of AMPK by the endurance exercise there was no inhibition of mTORC1 signaling or protein synthesis during recovery from resistance exercise. Study II utilized a similar set up, but with the difference that resistance exercise was performed with the triceps. The cycling exercise reduced the resistance exercise stimulated mTORC1 signaling immediately after the exercise, but during the recovery period mTORC1 signaling and protein synthesis was similar between trials. Concurrent exercise induced the mRNA expression of MuRF-1 and that of PGC-1α, the master regulator of mitochondrial biogenesis, in both studies, despite that the exercise modes in study II were separated between legs and arms. In study III, the effect of an EAA supplement with or without leucine, in the stimulation of mTORC1 signaling in connection with resistance exercise was examined. Intake of EAA robustly stimulated mTORC1 signaling after exercise, but this was only minor when leucine was excluded from the supplement. In study IV, subjects were supplied with leucine, BCAA, EAA or placebo in a randomized fashion during four sessions of resistance exercise. Leucine alone stimulated mTORC1 signaling after the exercise, but both the amplitude and extent of stimulation was substantially greater with EAA, an effect that was largely mediated by the BCAA as a group.

    In conclusion, endurance exercise prior to resistance exercise using the leg or arm muscles does not affect mTORC1 signaling or protein synthesis during the three hour recovery period from exercise, supporting compatibility between resistance- and endurance exercise induced signaling. Concurrent exercise increases the expression of the proteolytic marker MuRF-1 compared to resistance exercise only, which could indicate both and increased demand of cellular adaptive remodeling or a more direct detrimental proteolytic effect. Leucine is crucial among the EAA in the stimulation of mTORC1 signaling after exercise, its effect is however potentiated by intake of the remaining EAA. As a supplement a mixture of EAA must be regarded preferable, although the effect is largely mediated by the BCAA as a group.  

     

  • 14. Kazior, Zuzanna
    et al.
    Willis, Sarah J
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Apró, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Calbet, José A L
    Holmberg, Hans-Christer
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Endurance Exercise Enhances the Effect of Strength Training on Muscle Fiber Size and Protein Expression of Akt and mTOR.2016Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, nr 2, artikkel-id e0149082Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reports concerning the effect of endurance exercise on the anabolic response to strength training have been contradictory. This study re-investigated this issue, focusing on training effects on indicators of protein synthesis and degradation. Two groups of male subjects performed 7 weeks of resistance exercise alone (R; n = 7) or in combination with preceding endurance exercise, including both continuous and interval cycling (ER; n = 9). Muscle biopsies were taken before and after the training period. Similar increases in leg-press 1 repetition maximum (30%; P<0.05) were observed in both groups, whereas maximal oxygen uptake was elevated (8%; P<0.05) only in the ER group. The ER training enlarged the areas of both type I and type II fibers, whereas the R protocol increased only the type II fibers. The mean fiber area increased by 28% (P<0.05) in the ER group, whereas no significant increase was observed in the R group. Moreover, expression of Akt and mTOR protein was enhanced in the ER group, whereas only the level of mTOR was elevated following R training. Training-induced alterations in the levels of both Akt and mTOR protein were correlated to changes in type I fiber area (r = 0.55-0.61, P<0.05), as well as mean fiber area (r = 0.55-0.61, P<0.05), reflecting the important role played by these proteins in connection with muscle hypertrophy. Both training regimes reduced the level of MAFbx protein (P<0.05) and tended to elevate that of MuRF-1. The present findings indicate that the larger hypertrophy observed in the ER group is due more to pronounced stimulation of anabolic rather than inhibition of catabolic processes.

  • 15.
    Apro, William
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    Holmberg, Hans-Christer
    Mittuniversitetet.
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    High intensity interval cycling performed prior to resistance exercise stimulates autophagy signaling2016Inngår i: Conference program & abstracts, 2016, s. 84-84Konferansepaper (Annet vitenskapelig)
  • 16.
    Samuelsson, Hedvig
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Apró, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Intake of branched-chain or essential amino acids attenuates the elevation in muscle levels of PGC-1α4 mRNA caused by resistance exercise.2016Inngår i: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 311, nr 1, s. E246-E251Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The transcriptional co-activator PGC-1α is recognized as the master regulator of mitochondrial biogenesis. However, recently a novel isoform, PGC-1α4 that specifically regulates muscle hypertrophy was discovered. Since stimulation of mTORC1 activity is tightly coupled to hypertrophy, we hypothesized that activation of this pathway would upregulate PGC-1α4. Eight male subjects performed heavy resistance exercise (10 x 8-12 repetitions at ~75% of 1RM in leg press) on four different occasions, ingesting in random order a solution containing essential amino acids (EAA), branched-chain amino acids (BCAA), leucine or flavored water (placebo) during and after the exercise. Biopsies were taken from the vastus lateralis muscle before and immediately after exercise, as well as following 90 and 180 min of recovery. Signaling through mTORC1, as reflected in S6K1 phosphorylation, was stimulated to a greater extent by the EAA and BCAA than the leucine or placebo supplements. Unexpectedly, intake of EAA or BCAA attenuated the stimulatory effect of exercise on PGC-1α4 expression by ~50% (from a 10-fold to 5-fold increase with BCAA and EAA, P<0.05) 3 h after exercise, whereas intake of leucine alone did not reduce this response. The 60% increase (P<0.05) in the level of PGC-1α1 mRNA 90 min after exercise was uninfluenced by amino acid intake. Muscle glycogen levels were reduced and AMPKα2 activity and phosphorylation of p38 MAPK enhanced to the same extent with all four supplements. In conclusion, induction of PGC-1α4 does not appear to regulate the nutritional (BCAA or EAA) mediated activation of mTORC1 in human muscle.

  • 17.
    Apró, William
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Hamilton, D Lee
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Rooyackers, Olav
    Holmberg, Hans-Christer
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Leucine does not affect mechanistic target of rapamycin complex 1 assembly but is required for maximal ribosomal protein s6 kinase 1 activity in human skeletal muscle following resistance exercise.2015Inngår i: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 29, nr 10, s. 4358-4373Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We examined how the stimulatory effect of leucine on the mechanistic target of rapamycin complex 1 (mTORC1) pathway is affected by the presence of the remaining essential amino acids. Nine male subjects performed resistance exercise on 4 occasions and were randomly supplied essential amino acids (EAAs) with or without leucine (EAA-Leu), leucine alone, or flavored water (placebo; control). Muscle biopsies were taken from the vastus lateralis before and 60 and 90 min after exercise. Biopsies were analyzed for protein phosphorylation, kinase activity, protein-protein interactions, amino acid concentrations, and tracer incorporation. Leucine alone stimulated ribosomal protein s6 kinase 1 (S6K1) phosphorylation ∼280% more than placebo and EAA-Leu after exercise. Moreover, this response was enhanced by 60-75% after intake of EAAs compared with that of leucine alone (P < 0.05). Kinase activity of S6K1 reflected that of S6K1 phosphorylation; 60 min after exercise, the activity was elevated 3.3- and 4.2-fold with intake of leucine alone and with EAAs, respectively (P < 0.05). The interaction between mammalian target of rapamycin and regulatory-associated protein of mammalian target of rapamycin was unaltered in response to both resistance exercise and amino acid provision. Leucine alone stimulates mTORC1 signaling, although this response is enhanced by other EAA and does not appear to be caused by alterations in mTORC1 assembly.-Apró, W., Moberg, M., Hamilton, D. L., Ekblom, B., Rooyackers, O., Holmberg, H.-C., Blomstrand, E. Leucine does not affect mechanistic target of rapamycin complex 1 assembly but is required for maximal ribosomal protein s6 kinase 1 activity in human skeletal muscle following resistance exercise.

  • 18.
    Apró, William
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Hamilton, L.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    van Hall, G.
    Holmberg, HC
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Resistance exercise induced S6K1 kinase activity is not inhibited in human skeletal muscle despite prior activation of AMPK by high intensity interval cycling.2015Inngår i: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 308, nr 6, s. E470-E481Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Combining endurance and strength training in the same session has been reported to reduce the anabolic response to the latter form of exercise. The underlying mechanism, based primarily on results from rodent muscle, is proposed to involve AMPK-dependent inhibition of mTORC1 signaling. This hypothesis was tested in eight trained male subjects who in a randomized order performed either resistance exercise only (R) or interval cycling followed by resistance exercise (ER). Biopsies taken from the vastus lateralis before and after endurance exercise and repeatedly after resistance exercise were assessed for glycogen content, kinase activity, protein phosphorylation and gene expression. Mixed muscle fractional synthetic rate was measured at rest and during 3h of recovery using the stable isotope technique. In ER, AMPK activity was elevated immediately after both endurance and resistance exercise (~90%, P<0.05) but was unchanged in R. Thr389 phosphorylation of S6K1 was increased several-fold immediately after exercise (P<0.05) in both trials and increased further throughout recovery. After 90 and 180 min recovery, S6K1 activity was elevated (~55% and ~110%, respectively, P<0.05) and eEF2 phosphorylation was reduced (~55%, P<0.05) with no difference between trials. In contrast, markers for protein catabolism were differently influenced by the two modes of exercise; ER induced a significant increase in gene and protein expression of MuRF1 (P<0.05), which was not observed following R exercise only. In conclusion, cycling-induced elevation in AMPK activity does not inhibit mTORC1 signaling after subsequent resistance exercise, but may instead interfere with the hypertrophic response by influencing key components in protein breakdown.

  • 19.
    Moberg, Marcus
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Apró, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Ohlsson, Inger
    Pontén, Marjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    Villanueva, Antonio
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Absence of leucine in an essential amino acid supplement reduces activation of mTORC1 signalling following resistance exercise in young females.2014Inngår i: Applied Physiology, Nutrition and Metabolism, ISSN 1715-5312, E-ISSN 1715-5320, Vol. 39, nr 2, s. 183-94Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 20.
    Moberg, Marcus
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Apró, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    High-intensity cycling performed prior to resistance exercise does not influence mTORC1-signaling and the rate of muscle protein synthesis in the triceps brachii2014Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Introduction

    Endurance exercise can influence strength training adaptations when performed concurrently, with both inhibition (Kreamer 1995) and augmentation (Lundberg 2012) of muscular hypertrophy being reported. Our lab has set out to conduct a series of studies to examine the influence of endurance exercise on the acute stimulatory effect of resistance exercise on anabolic processes. In the present study, the effect of endurance exercise on a previously inactive muscle was investigated. The aim was to examine the influence of resistance exercise on mTORC1-signaling and rate of protein synthesis in the triceps brachii muscle with or without preceding intervals of high-intensity cycling. 

     

    Methods

    Eight trained males performed, in a randomized fashion, two sessions of heavy resistance exercise (RE) with the triceps muscles, where one session was preceded by intervals of high-intensity cycling (E+RE), 5 x 4 min at 85% of VO2 peak. Mixed muscle protein fractional synthetic rate (FSR) was measured at rest, prior to exercise, and during a 3 hour recovery period following exercise by continuous infusion of L-[ring-13C6] phenylalanine. Muscle biopsies from the triceps brachii was collected twice at rest separated by three hours, directly after resistance exercise and following 90 and 180 min of recovery. Signalling in the mTORC1-and AMPK-pathway was assessed using western blot technique.

     

    Results

    The same amount of work with regard to load, total number of repetitions and total time under tension was performed in the two trials. Muscle protein FSR increased from 0.050 ± 0.006 %/h at rest to 0.078 ± 0.008 and 0.082 ± 0.0016 %/h following E+RE and RE, respectively, with no difference between trials. Phosphorylation (P) of AMPKT172 was increased by 45-65% directly after exercise, similarly in both conditions, and regressed to a level approx. 20% lower than baseline following 180 min of recovery. P-mTORS2448 was increased 76 and 108% above rest directly after the E+RE and RE, respectively, and remained elevated in both trials during the entire recovery period. P-eEF2T56 was 20-36% higher directly after exercise but fell to a level that was 30-36% lower than pre-exercise and remained reduced during the entire recovery, with no difference between trials.

     

    Conclusion

    High-intensity endurance cycling does not influence the acute stimulation of anabolic signalling and muscle protein synthesis in the triceps brachii following resistance exercise.

     

     

    References

    Kreamer WJ et al. (1995) J Appl Physiol 78(3):976-989

    Lundberg T et al. (2013) J Appl Physiol 114: 81-89

  • 21.
    Moberg, Marcus
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Eva Blomstrands forskningsgrupp.
    Apró, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Eva Blomstrands forskningsgrupp.
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Eva Blomstrands forskningsgrupp.
    Aminosyror ökar träningseffekten2013Inngår i: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 22, nr 1, s. 45-49Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [sv]

    Kostens sammansättning är viktig för prestation och återhämtning. Dess innehåll av protein och essentiella aminosyror kan påverka musklernas anpassning till träning. Ny forskning visar att vissa aminosyror har en viktigare roll än att enbart agera som byggstenar eller energigivande näringsämnen.

  • 22.
    Borgenvik, Marcus
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Nordin, Marie
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Mattsson, C. Mikael
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Enqvist, Jonas K.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Eva Blomstrands forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Alterations in amino acid concentrations in the plasma and muscle in human subjects during 24 h of simulated adventure racing2012Inngår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 112, s. 3679-3688Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 23.
    Borgenvik, Marcus
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Eva Blomstrands forskningsgrupp.
    Apró, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Eva Blomstrands forskningsgrupp.
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Eva Blomstrands forskningsgrupp.
    Intake of branched-chain amino acids influences the levels of MAFbx mRNA and MuRF-1 total protein in resting and exercising human muscle.2012Inngår i: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 302, nr 5, s. E510-21Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Resistance exercise and amino acids are two major factors that influence muscle protein turnover. Here, we examined the effects of resistance exercise and branched-chain amino acids (BCAA), individually and in combination, on the expression of anabolic and catabolic genes in human skeletal muscle. Seven subjects performed two sessions of unilateral leg press exercise with randomized supplementation with BCAA or flavored water. Biopsies were collected from the vastus lateralis muscle of both the resting and exercising legs before and repeatedly after exercise to determine levels of mRNA, protein phosphorylation, and amino acid concentrations. Intake of BCAA reduced (P < 0.05) MAFbx mRNA by 30 and 50% in the resting and exercising legs, respectively. The level of MuRF-1 mRNA was elevated (P < 0.05) in the exercising leg two- and threefold under the placebo and BCAA conditions, respectively, whereas MuRF-1 total protein increased by 20% (P < 0.05) only in the placebo condition. Phosphorylation of p70(S6k) increased to a larger extent (∼2-fold; P < 0.05) in the early recovery period with BCAA supplementation, whereas the expression of genes regulating mTOR activity was not influenced by BCAA. Muscle levels of phenylalanine and tyrosine were reduced (13-17%) throughout recovery (P < 0.05) in the placebo condition and to a greater extent (32-43%; P < 0.05) following BCAA supplementation in both resting and exercising muscle. In conclusion, BCAA ingestion reduced MAFbx mRNA and prevented the exercise-induced increase in MuRF-1 total protein in both resting and exercising leg. Further-more, resistance exercise differently influenced MAFbx and MuRF-1 mRNA expression, suggesting both common and divergent regulation of these two ubiquitin ligases.

  • 24.
    Borgenvik, Marcus
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Apro, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Supplementation with BCAA Reduces MAFbx Expression and Phenylalanine Concentration in Rested and Exercised Human Muscle2011Inngår i: Medicine & Science in Sports & Exercise, 2011, Vol. 43, nr 5, s. 419-419Konferansepaper (Fagfellevurdert)
  • 25.
    Apró, William
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Rooyackers, O
    Holmberg, HC
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Leucine does not affect mTORC1 assembly but is required for maximal S6K1 activity in human skeletal muscle following resistance exerciseManuskript (preprint) (Annet vitenskapelig)
  • 26.
    Marcus, Moberg
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Apró, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    van Hall, Gerrit
    Holmberg, Hans-Christer
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Lower body endurance exercise acutely affects resistance exercise induced transcriptional and translational signalling in the tricpes brachii muscleManuskript (preprint) (Annet vitenskapelig)
1 - 26 of 26
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