Shigeki Ikegawa

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AIM This study investigated the force-velocity characteristics of the vastus lateralis (VL) muscle fascicle and muscle-tendon unit (MTU) in isolated lengthening and shortening actions, and during natural movement. METHODS Four subjects performed maximal eccentric and concentric knee extensions (60, 120 and 180 degrees s-1). Unilateral counter movement(More)
The cross-sectional areas (CSA) of fat, muscle and bone tissues of the limb as well as maximal voluntary isokinetic strength were measured in untrained men (n=27) and women (n=26) aged 18–25 years. Anatomical CSA of the three tissues were determined by ultrasound on the upper arm and thigh. The isokinetic strength of the elbow and knee extensor and flexor(More)
The purpose of this study was to investigate the development in muscle cross-sectional area (CSA) and strength capability of the reciprocal muscle groups in the upper arm and thigh. Subjects were 130 boys aged 7 to 18 years; 7-9 yr aged-group (n = 30), 10-12 yr (n = 30), 13-15 yr (n = 35), and 16-18 yr (n = 35). Anatomical CSAs of elbow flexors (EF), elbow(More)
The purpose of this study was to determine the effect of strength training in prepubescent boys and girls on muscle strength and cross-sectional area of upper arm. Subjects were ninety-nine healthy elementary school children who belonged to 1st, 3rd and 5th grades and they were assigned to two groups of training (N = 52) and control (N = 47). Training group(More)
We examined whether less convective heat loss during exercise at high altitude than at sea level was partially caused by reduced cutaneous vasodilation due to enhanced plasma water loss into contracting muscles and whether it was caused by hypoxia rather than by hypobaria. Seven young men performed cycling exercise for 40 min at 50% peak aerobic power in(More)
Nine healthy men (22-45 yr) completed 100 repetitive maximal isometric contractions of the ankle plantar flexor muscles in two knee positions of full extension (K0) and flexion at 90 degrees (K90), positions that varied the contribution of the gastrocnemii. Electromyographic activity was recorded from the medial and lateral gastrocnemii and soleus muscles(More)
Iksokinetic strength and cross-sectional area (CSA) of knee extensor muscles were examined in 60 boys and girls, aged 6–9 years, and in 71 young adult men and women to investigate the influences of age and gender on the strength capabilities in relation to muscle size. A single anatomical CSA of quadriceps femoris at the right mid-thigh was measured by(More)
Age changes in the cross-sectional areas (CSAs) of fat and muscle tissues of limbs were investigated by using a B-mode ultrasonic technique for 245 males and 275 females aged 6 to 60 years. Four measurement sites were selected in the right limbs: the forearm, upper arm, lower leg and thigh. In an age span from 13 to 15 years, fat CSA for males decreased,(More)
The force generation capacity, during 50 repeated maximal knee extensions with a constant velocity of 3.14 rad · s−1, and cross-sectional area (CSA) of the quadriceps femoris muscles were determined for untrained women (n = 36) and men (n = 27) aged from 18 to 25 years. As force scores in the maximal repetitions, the mean values of force ( $$\bar F$$ ) of(More)
In order to understand the possible mechanisms contributing to enhanced concentric performance in stretch-shortening cycle exercises in vivo the present study examined knee extension torque, electromyogram (EMG) activity and fascicle length of the vastus lateralis muscle in maximal and submaximal human movements. Maximal concentric knee extensions (120(More)