Low-load high volume resistance exercise stimulates muscle protein synthesis more than high-load low volume resistance exercise in young men.
BACKGROUND
We aimed to determine the effect of resistance exercise intensity (%1 repetition maximum-1RM) and volume on muscle protein synthesis, anabolic signaling, and myogenic gene expression.


RESULTS
Fifteen men (21+/-1 years; BMI=24.1+/-0.8 kg/m2) performed 4 sets of unilateral leg extension exercise at different exercise loads and/or volumes: 90% of repetition maximum (1RM) until volitional failure (90FAIL), 30% 1RM work-matched to 90%FAIL (30WM), or 30% 1RM performed until volitional failure (30FAIL). Infusion of [ring-13C6] phenylalanine with biopsies was used to measure rates of mixed (MIX), myofibrillar (MYO), and sarcoplasmic (SARC) protein synthesis at rest, and 4 h and 24 h after exercise. Exercise at 30WM induced a significant increase above rest in MIX (121%) and MYO (87%) protein synthesis at 4 h post-exercise and but at 24 h in the MIX only. The increase in the rate of protein synthesis in MIX and MYO at 4 h post-exercise with 90FAIL and 30FAIL was greater than 30WM, with no difference between these conditions; however, MYO remained elevated (199%) above rest at 24 h only in 30FAIL. There was a significant increase in AktSer473 at 24h in all conditions (P=0.023) and mTORSer2448 phosphorylation at 4 h post-exercise (P=0.025). Phosporylation of Erk1/2Tyr202/204, p70S6KThr389, and 4E-BP1Thr37/46 increased significantly (P<0.05) only in the 30FAIL condition at 4 h post-exercise, whereas, 4E-BP1Thr37/46 phosphorylation was greater 24 h after exercise than at rest in both 90FAIL (237%) and 30FAIL (312%) conditions. Pax7 mRNA expression increased at 24 h post-exercise (P=0.02) regardless of condition. The mRNA expression of MyoD and myogenin were consistently elevated in the 30FAIL condition.


CONCLUSIONS
These results suggest that low-load high volume resistance exercise is more effective in inducing acute muscle anabolism than high-load low volume or work matched resistance exercise modes.
Burd
Nicholas A
NA
Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
West
Daniel W D
DW
Staples
Aaron W
AW
Atherton
Philip J
PJ
Baker
Jeff M
JM
Moore
Daniel R
DR
Holwerda
Andrew M
AM
Parise
Gianni
G
Rennie
Michael J
MJ
Baker
Steven K
SK
Phillips
Stuart M
SM
D015444:Exercise / Q000502:physiology*; D005786:Gene Expression Regulation; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism; D009124:Muscle Proteins / Q000096:biosynthesis* / Q000235:genetics; D018006:Myogenic Regulatory Factors / Q000235:genetics; D051763:PAX7 Transcription Factor / Q000235:genetics; D010649:Phenylalanine / Q000097:blood / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D055070:Resistance Training; D015398:Signal Transduction; D016474:Weight-Bearing / Q000502:physiology*; D055815:Young Adult
D009124:Muscle Proteins; D018006:Myogenic Regulatory Factors; D051763:PAX7 Transcription Factor; C497321:PAX7 protein, human; D012333:RNA, Messenger; D010649:Phenylalanine