ABSTRACT

　This study aimed to clarify which musculature characteristics is directly related withimprovement of sprint performance by examining trunk and lower extremity musclecross-sectional area change before and after training period. Twelve collegiate malesprinters and hurdlers took part in this study （age 20.4±0.5 yrs, height 172.3±4.5cm, body mass 64.7±5.9 kg）．Cross-sectional images from the origin to insertion of21 trunk and lowerlimb muscles were obtained with via magnetic resonance imaging（MRI）．The absolute cross-sectional areas of each muscle were calculated as indices of muscularity using images. The participants performed two 60-m maximalsprint on a synthetic surface track wearing spiked shoes. After experiment, theywere divided two groups, one is V+ group （the participants of this group improvedmaximal sprint velocity of 60-m sprints）， the other is V- group（ The others decreasedthat）．We focused the difference of muscle cross-sectional areas change before andafter training session between V+ group and V- group, and explored which skeletalmuscle was related with sprint performances. Significant simple correlation withmaximal sprint velocity was found for 13 muscularity indices （abdominal oblique andtransverse abdominal, psoas major, erector spinae, gluteus maximus, gluteus mediasand minimus, vastus lateralis, vastus intermidius, vastus medialis, sartorius, bicepsfemoris, semitendinous, semimembranosus and gracilis）．On the other hands, changevalue of psoas major, erector spinae, gluteus maximus and semitendinous beforeand after training session is significantly different between V+ group and V- group.These findings suggest that muscularity indices of psoas major, erector spinae, gluteusmaximus and semitendinous play a significant role in sprint performance.

DECENTE SPORTS SCIENCE Vol.40/The DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE