Assessment of Cruris Muscle Composition in High School Athletes

—Analysis of cruris muscle cross-section area using B-mode ultrasound—

Abstract

We described all cross sectioned images of the cruris on 1 screen using a curved array type probe, and tried to measure the cruris muscle cross-sectional area. The usefulness of a ratio of a dorsi/plantar flexor, relation to ankle joint muscular power, and an evaluation index for a test of physical strength and fitness was examined using the cruris muscle cross section product obtained by this method. This made the control group five generally healthy men which amounted to ten legs made up of 26 high school male sport players (a total of 52 legs) that did not have an exercise habit. Depiction of cruris muscle by the ultrasonic wave was performed at 30% of distant position of tibia length from the tibia point in the posterior position (on gastrocnemius) using 2-5MHz extensive zone curved array type probe (HDI 5000 by the ATL company). Isokinetic muscular power was measured using Cybex350, the peak torque value of ankle joint dorsi flexion and plantar flexion power was also measured. The muscle cross-sectional area of a high school male sport player showed a higher value than that of a generally healthy persons. The ratio of the ankle joint dorsi/plantar flexor, it turns out in a muscle cross-sectional area that a dorsi flexor becomes about 30% of that in a plantar flexor. Isokinetic muscle power was about 40% at 180 deg/s and about 30% at 60 deg/s. It is thought that measurement of muscle cross-sectional area using the ultrasonic dislocation method is valid as an evaluation index in a test of physical strength and fitness since all cross section images could be described on 1 screen without damage and correlation with muscular power accepted. For comparison with CT or MRI, it is thought that using phsiological cross-sectional area with consideration of the device of the measurement position for obtaining the maximum of a plantar flexor group further from now on, or the direction of pennation angle and muscle fiber that it is necessary to reexamine.