The primary focus of this thesis was to investigate the operating vastus lateralis (VL) fascicle lengths during the turn-cable exercise. The secondary objective was to determine possible changes in the torque-angle relationship in speed skaters caused by preseason training and the potential differences in the torque-angle relationship between sub-elite speed skaters and strength-trained control subjects. In the first study, we recruited 16 long track speed skaters and 16 strength-trained control subjects to perform maximal isometric knee extensions at nine different knee joint angles, ranging from 20- 120°. Maximal voluntary knee extension torque, knee joint angle, and surface electromyography (EMG) were measured before and after 3-months of preseason training in the speed skaters. Maximal torque, optimal knee angle, and torque-angle relationship did not change in the speed skaters following preseason training, nor were there any differences between the skaters and control subjects. Speed skaters were found to operate on the descending limb of the torque-angle relationship during the gliding phase of skating, and the plateau and ascending limb during the push-off phase, using the knee extensors in what appears to be an optimal way. In the second study, 16 long track speed skaters performed the same maximal isometric knee extension test as described before followed by the turn-cable test which required them to perform crossover skating strokes on a treadmill. Maximal voluntary knee extension torque, knee joint angle, surface EMG, and lateral force were measured for both tests. We found that the left VL muscle of sub-elite long track speed skaters operated on the descending limb of the force-length relationship during the gliding phase of the turn-cable exercise while the push-off phase covered the entire plateau region. The findings from the two studies indicate that sub-elite speed skaters maximize their force generating potential by taking advantage of the plateau region of both the knee extensor torque-angle relationship and VL force-length relationship.