The purpose of this study was to examine the fatigue response of the quadriceps femoris muscle to two patterns of high frequency alternating electrical current. Muscle fatigue was evaluated by the comparison of isometric torque fluctuations during the 10-minute application of both stimulus patterns. Muscle fatigue was also assessed during an isokinetic fatigue test which immediately followed both stimulation patterns. The results indicated that greater amounts of electrical stimulation produced lower current-induced contraction intensities with a greater amount of fatigue. During the isokinetic fatigue test, smaller (P < 0.01) exponential peak torque declines were observed following greater amounts of electrical stimulation. This suggested that high frequency current may selectively fatigue fast twitch (FT) muscle fibers. Therefore, it was concluded that selective stimulation of FT muscle fibers may be an important component explaining the mechanism of strength increases following application of high frequency alternating current.

J Orthop Sports Phys Ther 1986;7(4):145-153.

A function-limiting knee extension contracture following an intra-articular femur fracture was treated with traditional conservative and surgical intervention without satisfactory results. A new treatment program was planned which included a combination of heat, ice, prolonged passive stretch, and exercise. The patient regained functional knee flexion and was able to return to preinjury athletic activities. The treatment protocol described offers a time consuming, but effective approach to treating knee extension contractures resistant to surgical and traditional conservative management.

J Orthop Sports Phys Ther 1986;7(4):159-162.

The effect of the heel lift to correct a limb length difference was studied by electrogoniometry (elgons) in four male subjects with a limb length inequality between 3/~6 inch (0.48 cm) and 3h inch (0.95 cm). Six elgons were attached to bilateral hip, knee, and ankle joints as the subject walked (3 mph) and jogged (6 mph) on the treadmill twice, once with the heel lift and once without. Recordings from the elgons examined maximal flexion and extension during support and swing phase, amplitude of movement (ROM), duration of each movement, and angular velocity of each joint. Within the limitations of the study, the following conclusions were drawn: 1) the addition of a heel lift did not appear to significantly affect biomechanical measures of gait; and 2) insertion of a heel lift did tend to cause more symmetrical movement for the maximum angle of hip extension and ROM of the swing plantarflexion phase of the ankle but more asymmetrical ROM of the swing flexion phase of the knee.

J Orthop Sports Phys Ther 1986;7(4):173-179.

Recent, more sensitive measures of iron status indicate a prevalence of iron deficiency, with or without anemia, among young women, children, and adolescent males participating in strenuous physical activity. Anemia primarily restricts brief, intense exercise; whereas iron deficiency limits performance of endurance activities. The impact of iron deficiency on oxidative capacity of muscle, protein synthesis, growth, behavior, and body temperature regulation are reviewed. The widespread effects of iron deficiency warrant closer attention to the iron status of athletes and the practice of dietary iron supplementation in the intervention and prevention of iron deficiency.

J Orthop Sports Phys Ther 1986;7(4):192-195.