The purpose of this study was to quantify the elastic properties of tendon structures in vivo and to investigate the influence of the tendon properties on jump performance with and without countermovement. Elongation of the tendon and aponeurosis of vastus lateralis muscle (dL) was directly measured by ultrasonography while subjects (n = 31) performed ramp isometric knee extension up to the vol...

Jumping on an elastic surface produces a number of sensory and motor adjustments. This effect caused by jumping on the trampoline has been called "trampoline aftereffect". The objective of the present study was to investigate the neuromuscular response related with this effect. A group of 15 subjects took part in an experimental session, where simultaneous biomechanical and electromyographic (E...

PURPOSE This study investigated the influence of static stretching exercises on specific exercise performances. METHODS Thirty-eight volunteers participated in this study. The stretching group (STR) consisted of 8 males and 11 females whose activity was limited to a 10-wk, 40-min, 3-d.wk(-1) static stretching routine designed to stretch all the major muscle groups in the lower extremity. The ...

The effects of multi-ingredient performance supplements (MIPS) on perceived soreness, strength, flexibility and vertical jump performance following eccentric exercise are unknown. The purpose of this study was to determine the impact of MIPS (NO-Shotgun®) pre-loaded 4 weeks prior to a single bout of downhill running (DHR) on muscle soreness and performance. Trained male runners (n = 20) were st...

Vitamin D is thought to regulate skeletal muscle function and boost physical performance. The aim of this study was to assess the relationship between vitamin D and physical performance in physically active children. This cross-sectional study included 125 children who practice football as a leisure activity. Plasma 25-hydroxyvitamin D (25-OHD) was assessed using a chemiluminescence immunoassay...

Several arboreal mammals have the ability to rapidly and repeatedly jump vertical distances of 2m, starting from rest. We characterize this performance by ametric we call vertical jumping agility. Through basic kinetic relations, we show that this agility metric is fundamentally constrained by available actuator power. Although rapid high jumping is an important performance characteristic, the ...

International Journal of Exercise Science 7(4) : 260-­270, 2014. Change-­of-­direction speed (CODS) is an important quality to performance in multi-­direction sports. The relationship between CODS in the frontal plane and power, strength, and reactive strength is largely unstudied. Twenty-­three male college students participated in this study. The study used a -­moment correlation to measure t...

The purpose of this study was to test the effect of a jump-training program on landing mechanics and lower extremity strength in female athletes involved in jumping sports. These parameters were compared before and after training with those of male athletes. The program was designed to decrease landing forces by teaching neuromuscular control of the lower limb during landing and to increase ver...