Simple tests for surveying muscle strength and muscle stiffness in sportsmen

Thirty-nine elite runners were examined by Cybex II for thigh muscle strength. In addition, the maximal abduction, flexion and extension in the hip, dorsal flexion in the ankle, standing five steps, long and vertical jump, and side and front split were measured. For the latter five tests, an ordinary measuring tape was used. To establish reference values, 111 district level runners and 24 keep-fit joggers were examined by the three jump tests and the side and front split. Twenty randomly selected runners were examined twice to determine the reproducibility. The mean CV% was 1.9 +/- 1.4. There was a statistically significant correlation between the results in the vertical jump, the standing five steps, and long jump and muscle strength (P less than 0.001), in particular as to the values in the higher angle velocity. Furthermore, there was a correlation (P less than 0.001) between the results in side and front split and the hip. There was a covariation between the three ranges of motion, suggesting that stiffness in the hip was a general condition involving all directions of movements. The sensitivity for the jump tests and the side/front splits was 75%-91%. The specificity for the same test varied between 70% and 100%.