Strength of isometric and isokinetic contractions: knee muscles of men aged 20 to 86.

Maximum isometric and isokinetic torques of the knee flexor and extensor muscles were measured at three knee joint positions in 72 normal, health men in three age groups from 20 to 86 years. The isokinetic contractions were performed at a speed of 36 degrees per second. The isometric contractions were sustained for five seconds. Strength of the men in the older age groups was significantly less than that of the youngest group. The strength of the isokinetic contractions was significantly less than that of the isometric contractions for all joint positions. The men in the oldest age group generally took longer than the younger men to reach peak torque during the isometric contractions. The torque values provide base-lines for evaluating patients with knee joint disabilities.