Abstract

The purpose was to relate certain structural characteristics of vastus lateralis and gastrocnemius muscles to the time-force parameters of explosive dynamic efforts. Needle biopsy was used to obtain samples of the two muscles. The subjects were jumper athletes in training (eight male and five female high jumpers (HJ) and six male long jumpers (LJ). The biopsy samples were used to estimate percentage distribution of fast (FF) and slow (SF) twitch fibres, mean fibre area and ratio as well as fibre count related to the cross-sectional area of the thigh. Sargent jump and downward jump were used as power tests and were performed on a force platform. The time recording of vertical force was evaluated to obtain two parameters of strength and three, respectively four indices of timing. Flight time served to calculate the height of verticalelevation. The obtained structural data of the fibres showed acceptable agreement with previous results. There were substantial differences between the three groups of subjects. Group LJ had higher percentage of FF than Group HJ (52.2 and 45.0, respectively 42.0 and 37.4). FF percentage in the gastrocnemius was higher than in the other muscle in the females (50.0) while in the males the opposite was true. FF count was higher in both muscles in the LJ than in the HJ males. Verf.-Referat (gekuerzt)