Myogenic, matrix and growth factor mRNA expression in human skeletal muscle: effect of contraction intensity and feeding

TY - JOUR

T1 - Myogenic, matrix and growth factor mRNA expression in human skeletal muscle: effect of contraction intensity and feeding

AU - Agergaard, Jakob

AU - Reitelseder, Søren

AU - Pedersen, T.G.

AU - Doessing, Simon

AU - Schjerling, Peter

AU - Langberg, Henning

AU - Miller, Benjamin F

AU - Aagaard, P

AU - Kjær, Michael

AU - Holm, Lars

PY - 2013/5

Y1 - 2013/5

N2 - INTRODUCTION: We examined short-term (3-hour) and long-term (12-week) training effects after heavy load [HL; 70% 1RM] and light load (LL; 16% 1RM) exercise. METHODS: mRNA expression of genes involved in skeletal muscle remodeling were analyzed and muscle activity (EMG measurements) was measured. RESULTS: Relative muscle activity differed between HL and LL resistance exercise, whereas median power frequency was even, suggesting an equal muscle-fiber-type recruitment distribution. mRNA expression of Myf6, myogenin, and p21 was mostly increased, and myostatin was mostly depressed by HL resistance exercise. No major differences were seen in atrophy-related genes between HL and LL resistance exercise. No changes were seen over 12-week training for any of the targets. CONCLUSIONS: Resistance exercise at LL and HL elevated the expression of genes involved in skeletal muscle hypertrophy, although the greatest response was from HL. However, no long-term effect from either LL or HL resistance exercise was seen on basal levels of the mRNA targets.

AB - INTRODUCTION: We examined short-term (3-hour) and long-term (12-week) training effects after heavy load [HL; 70% 1RM] and light load (LL; 16% 1RM) exercise. METHODS: mRNA expression of genes involved in skeletal muscle remodeling were analyzed and muscle activity (EMG measurements) was measured. RESULTS: Relative muscle activity differed between HL and LL resistance exercise, whereas median power frequency was even, suggesting an equal muscle-fiber-type recruitment distribution. mRNA expression of Myf6, myogenin, and p21 was mostly increased, and myostatin was mostly depressed by HL resistance exercise. No major differences were seen in atrophy-related genes between HL and LL resistance exercise. No changes were seen over 12-week training for any of the targets. CONCLUSIONS: Resistance exercise at LL and HL elevated the expression of genes involved in skeletal muscle hypertrophy, although the greatest response was from HL. However, no long-term effect from either LL or HL resistance exercise was seen on basal levels of the mRNA targets.

U2 - 10.1002/mus.23667

DO - 10.1002/mus.23667

M3 - Journal article

SN - 0148-639X

VL - 47

SP - 748

EP - 759

JO - Muscle & Nerve

JF - Muscle & Nerve

IS - 5

ER -