TY - JOUR
T1 - Energy metabolism during repeated sets of leg press exercise leading to failure or not
AU - Gorostiaga, Esteban M
AU - Navarro-Amézqueta, Ion
AU - Calbet, José A L
AU - Hellsten, Ylva
AU - Cusso, Roser
AU - Guerrero, Mario
AU - Granados, Cristina
AU - González-Izal, Miriam
AU - Ibañez, Javier
AU - Izquierdo, Mikel
N1 - CURIS 2012 5200 133
PY - 2012/7/13
Y1 - 2012/7/13
N2 - This investigation examined the influence of the number of repetitions per set on power output and muscle metabolism during leg press exercise. Six trained men (age 34±6 yr) randomly performed either 5 sets of 10 repetitions (10REP), or 10 sets of 5 repetitions (5REP) of bilateral leg press exercise, with the same initial load and rest intervals between sets. Muscle biopsies (vastus lateralis) were taken before the first set, and after the first and the final sets. Compared with 5REP, 10REP resulted in a markedly greater decrease (P<0.05) of the power output, muscle PCr and ATP content, and markedly higher (P<0.05) levels of muscle lactate and IMP. Significant correlations (P<0.01) were observed between changes in muscle PCr and muscle lactate (R2 = 0.46), between changes in muscle PCr and IMP (R2 = 0.44) as well as between changes in power output and changes in muscle ATP (R2 = 0.59) and lactate (R2 = 0.64) levels. Reducing the number of repetitions per set by 50% causes a lower disruption to the energy balance in the muscle. The correlations suggest that the changes in PCr and muscle lactate mainly occur simultaneously during exercise, whereas IMP only accumulates when PCr levels are low. The decrease in ATP stores may contribute to fatigue.
AB - This investigation examined the influence of the number of repetitions per set on power output and muscle metabolism during leg press exercise. Six trained men (age 34±6 yr) randomly performed either 5 sets of 10 repetitions (10REP), or 10 sets of 5 repetitions (5REP) of bilateral leg press exercise, with the same initial load and rest intervals between sets. Muscle biopsies (vastus lateralis) were taken before the first set, and after the first and the final sets. Compared with 5REP, 10REP resulted in a markedly greater decrease (P<0.05) of the power output, muscle PCr and ATP content, and markedly higher (P<0.05) levels of muscle lactate and IMP. Significant correlations (P<0.01) were observed between changes in muscle PCr and muscle lactate (R2 = 0.46), between changes in muscle PCr and IMP (R2 = 0.44) as well as between changes in power output and changes in muscle ATP (R2 = 0.59) and lactate (R2 = 0.64) levels. Reducing the number of repetitions per set by 50% causes a lower disruption to the energy balance in the muscle. The correlations suggest that the changes in PCr and muscle lactate mainly occur simultaneously during exercise, whereas IMP only accumulates when PCr levels are low. The decrease in ATP stores may contribute to fatigue.
U2 - 10.1371/annotation/ca21efee-84a1-4031-9dcd-224af64b7753
DO - 10.1371/annotation/ca21efee-84a1-4031-9dcd-224af64b7753
M3 - Journal article
C2 - 22808209
SN - 1932-6203
VL - 7
JO - P L o S One
JF - P L o S One
IS - 7
M1 - e40621
ER -