title: Difference in the recruitment of hip and knee muscles between back squat and plyometric squat jump.
abstract: Athletes who aim to improve both muscular endurance and power often perform exercises that involve similar joint actions under different lifting conditions, such as changes in the load or speed, which are implemented at different times during a periodized exercise program or simultaneously. The prescribed exercises are considered to recruit the same muscles even if the lifting conditions differ to each other. The present study aimed to clarify this by examining whether the recruitment of individual hip and knee muscles during the squat exercise differs between lifting conditions adopted for muscular endurance and power training regimens. Moderately trained men performed back squats (BS), with a load of approximately 60% of one repetition maximum, as a muscular endurance training exercise, and they performed plyometric squat jumping (PSJ) for power training. During each exercise, the lower limb joint torques and the recruitment of five hip and knee muscles were determined with inverse-dynamics and T2-weighted magnetic resonance imaging, respectively. While the maximal and mean knee joint torques were greater during PSJ than during BS (p<0.01), the T2 values for the quadriceps femoris muscle did not differ between the exercises. In contrast, the T2 values of the gluteus maximus and hip adductor muscles were higher during PSJ (p<0.05) than during BS, although there was no significant difference in the mean hip extension torque between the two exercises. The current results indicate that the individual use of the agonist muscles differs between BS and PSJ, and it does not always correspond with the joint kinetics during the exercises. Therefore, in addition to the exercise type, the lifting condition should also be taken into consideration as a determinant of the major muscles trained during a resistance exercise.
authors: Center for Environment, Health and Field Sciences, Chiba University, Kashiwa, Chiba, Japan; Waseda Institute for Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan.
authors: Norihide
authors: N
authors: Sugisaki
authors: Center for Liberal Arts, Meiji Gakuin University, Yokohama, Kanagawa, Japan.
authors: Sadao
authors: S
authors: Kurokawa
authors: Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan.
authors: Junichi
authors: J
authors: Okada
authors: National Institute of Fitness and Sports in Kanoya, Kanoya, Kagoshima, Japan.
authors: Hiroaki
authors: H
authors: Kanehisa
mesh_terms: D000328:Adult; D006615:Hip / Q000502:physiology*; D006801:Humans; D007596:Joints / Q000502:physiology; D007717:Knee / Q000502:physiology*; D008124:Locomotion / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D059385:Plyometric Exercise; D013997:Time Factors; D019415:Torque