The purpose of this study was to determine the specific muscles that may contribute to sprint performance. Eleven female 100-m sprinters and nine non-sprinters volunteered. Thigh muscle volume (MV) was measured using ...The purpose of this study was to determine the specific muscles that may contribute to sprint performance. Eleven female 100-m sprinters and nine non-sprinters volunteered. Thigh muscle volume (MV) was measured using magnetic resonance imaging (MRI) images obtained from the spina iliaca anterior-superior to below the distal end of the femur. The MV of the adductors, quadriceps and hamstrings was calculated. Evidence for the null/alternative hypothesis was provided thorough the calculation of Bayes Factors (BF10). Differences represented as median δ(95% credible interval). Absolute MVs in the quadriceps [1.287 (0.315, 2.39), BF10: 14.3], hamstrings [3.032 (1.886, 4.482), BF10: 9487.4] and adductors [3.22 (1.994, 4.654), BF10: 23,360.2] were greater in sprinters than in non-sprinters. This was also observed when MV was normalized to body mass (cm3/kg). Absolute and relative MVs in the adductor longus, the adductor brevis, the adductor magnus, pectineus, and gracilis were also greater in the sprinters. However, percentage of component adductor relative to total adductors MV appeared similar between the two groups. There was no evidence for a correlation between sprint time and quadriceps, hamstrings and adductors MV relative to body mass. Within the adductors, there was evidence for a correlation between sprint time and adductor brevis MV relative to body mass [r = −0.652, BF10: 3.028, δ−0.548 (−0.870, 0.040)]. Although the credible interval was wide, our results suggest that the adductor brevis may contribute to sprint running performance in female sprinters. This may be related, in part, to supporting the flexion and medial rotation of the thigh.展开更多
We experimentally demonstrate a 4-Gb/s radio-over-fiber （RoF） system with 40-kin fiber and 2-m wireless distance downstream at 100-GHz carrier. To the best of our knowledge, this is for the first time in China to re...We experimentally demonstrate a 4-Gb/s radio-over-fiber （RoF） system with 40-kin fiber and 2-m wireless distance downstream at 100-GHz carrier. To the best of our knowledge, this is for the first time in China to realize optical wireless link at 100 GHz. In this letter, simple intensity modulator with direct detector （IM-DD） modulation is employed and optical power penalty afZer 40-kin single mode fiber （SMF）-28 and 2-m air link is 3.2 dB with bit-error-rate （BER） at 1 × 10- 9.展开更多
文摘The purpose of this study was to determine the specific muscles that may contribute to sprint performance. Eleven female 100-m sprinters and nine non-sprinters volunteered. Thigh muscle volume (MV) was measured using magnetic resonance imaging (MRI) images obtained from the spina iliaca anterior-superior to below the distal end of the femur. The MV of the adductors, quadriceps and hamstrings was calculated. Evidence for the null/alternative hypothesis was provided thorough the calculation of Bayes Factors (BF10). Differences represented as median δ(95% credible interval). Absolute MVs in the quadriceps [1.287 (0.315, 2.39), BF10: 14.3], hamstrings [3.032 (1.886, 4.482), BF10: 9487.4] and adductors [3.22 (1.994, 4.654), BF10: 23,360.2] were greater in sprinters than in non-sprinters. This was also observed when MV was normalized to body mass (cm3/kg). Absolute and relative MVs in the adductor longus, the adductor brevis, the adductor magnus, pectineus, and gracilis were also greater in the sprinters. However, percentage of component adductor relative to total adductors MV appeared similar between the two groups. There was no evidence for a correlation between sprint time and quadriceps, hamstrings and adductors MV relative to body mass. Within the adductors, there was evidence for a correlation between sprint time and adductor brevis MV relative to body mass [r = −0.652, BF10: 3.028, δ−0.548 (−0.870, 0.040)]. Although the credible interval was wide, our results suggest that the adductor brevis may contribute to sprint running performance in female sprinters. This may be related, in part, to supporting the flexion and medial rotation of the thigh.
基金supported by the National "973" Program of China(No.2010CB328300)the National Natural Science Foundation of China(Nos.61107064,61177071,and 600837004)+1 种基金the Doctoral Fund of Ministry of Education,the Open Fund of State Key Lab of ASIC&System(No.11MS009)the Open Fund of State Key Lab of Information Photonics and Optical Communications
文摘We experimentally demonstrate a 4-Gb/s radio-over-fiber （RoF） system with 40-kin fiber and 2-m wireless distance downstream at 100-GHz carrier. To the best of our knowledge, this is for the first time in China to realize optical wireless link at 100 GHz. In this letter, simple intensity modulator with direct detector （IM-DD） modulation is employed and optical power penalty afZer 40-kin single mode fiber （SMF）-28 and 2-m air link is 3.2 dB with bit-error-rate （BER） at 1 × 10- 9.
