Normative data for muscle strength in relation to age, knee angle and velocity.

Standardized normal values are necessary to assess the performance with respect to the momentary functional state as well as a documentation of a training or rehabilitation program. The isokinetic extension strength of the right and left knee was investigated in 147 healthy male subjects between 17 and 70 years who were divided into 6 age groups. Normative data are given in dependence on age, knee angle and various velocities and regression equation in relation to the knee angle and for the peak torque in relation to the angular velocity. We found a significant decrease in maximum torque with increasing angle acceleration (p < 0.001) and a correlation between strength and body mass (p < 0.05). The highest values were found in the group of 20- to 29-year olds, while the strength was lower up to age 20. The decrease in force between 25 to 70 years ranges up to 37% at a velocity of 10 degrees/s, up to 41% at a velocity of 60 degrees/s and up to 50% at a velocity of 180 degrees/s.