Influence of Lower Leg Rotation on Knee Joint Extension Torque and Work Load

[Purpose] To clarify the effect of lower leg rotation on knee joint extension torque and work load in knee extension exercise. [Subjects and Methods] The subjects were 20 healthy male adults. Knee extension torque was measured using a Biodex System 3. Maximum isokinetic knee extension exercise was performed from knee flexion of 90 to 30° at angular velocities of 60, 180 and 300°/sec. The value, time and angle of peak torque, and the initial and final work loads were compared among the neutral, and externally and internally rotated positions of the lower leg. [Results] At an angular velocity of 60°/sec, the neutral position elicited significantly greater average values of peak torque, and both the initial and final work loads than either the externally or internally rotated leg positions. [Conclusion] These results suggest that strengthening knee extension torque with the lower leg internally and externally rotated might help to prevent injury.