2002 Volume 47 Issue 5 Pages 463-472
A follow-up method was used to study the progress of sprint performance in one female sprinter from the age of 19 to 24 years. Measurements were performed annually every November for maximum sprint speed, stride frequency, stride length, and sprint motion of the angular kinematics over 60 m at full sprint. In addition, the isokinetic peak torques during knee extension and flexion were measured at 60, 180, and 300 deg/s. Magnetic resonance imaging (MRI) was used to determine the muscle cross-sectional area of the thigh (upper: 70%). The best sprint speed was 8.78 m/s at 24 years old, and stride length and stride frequency were 1.93 m and 4.55 Hz, respectively. The percentages at 24 years old were 102.5%, 101.6%, and 100.0%, respectively, when sprint speed, stride length and stride frequency at 19 years old were set as 100%. The purpose of the sprint training was to reduce flexion and extension of the knee joint during the support phase and quicken leg swing velocity. From 19 to 24 years of age, the knee joint angle at the moment of foot contact and release showed no clear change. However, the maximal knee flexion angular velocity decreased by 27.3%, while leg swing velocity increased by 6.8%. The purpose of the physical fitness training was mainly to strengthen the muscle force of the hamstrings in the femoral region. From 21 to 24 years of age, iso-kinetic peak torques during knee fiexion (angular velocity; 180, and 300 deg/s) showed increases of 40-70%, and that of hamstrings in the thigh also increased by 16%. Furthermore, fat in a cross-sectional area of the femoral region decreased markedly by about 30% between 19 and 24 years of age. These results suggest that sprint training using scientific knowledge improved the sprint performance of this subject.