Joint Kinetics and Kinematics During Common Lower Limb Rehabilitation Exercises.

Context: Unilateral body-weight exercises are commonly used to strengthen the lower limbs during rehabilitation after injury, but data comparing the loading of the limbs during these tasks are limited.
Objective: To compare joint kinetics and kinematics during 3 commonly used rehabilitation exercises.
Design: Descriptive laboratory study.
Setting: Laboratory.
Patients or Other Participants: A total of 9 men (age = 22.1 ± 1.3 years, height = 1.76 ± 0.08 m, mass = 80.1 ± 12.2 kg) participated.
Intervention(s): Participants performed the single-legged squat, forward lunge, and reverse lunge with kinetic data captured via 2 force plates and 3-dimensional kinematic data collected using a motion-capture system.
Main Outcome Measure(s): Peak ground reaction forces, maximum joint angles, and peak sagittal-joint moments.
Results: We observed greater eccentric and concentric peak vertical ground reaction forces during the single-legged squat than during both lunge variations (P ≤ .001). Both lunge variations demonstrated greater knee and hip angles than did the single-legged squat (P < .001), but we observed no differences between lunges (P > .05). Greater dorsiflexion occurred during the single-legged squat than during both lunge variations (P < .05), but we noted no differences between lunge variations (P = .70). Hip-joint moments were greater during the forward lunge than during the reverse lunge (P = .003) and the single-legged squat (P = .011). Knee-joint moments were greater in the single-legged squat than in the reverse lunge (P < .001) but not greater in the single-legged squat than in the forward lunge (P = .41). Ankle-joint moments were greater during the single-legged squat than during the forward lunge (P = .002) and reverse lunge (P < .001).
Conclusions: Appropriate loading progressions for the hip should begin with the single-legged squat and progress to the reverse lunge and then the forward lunge. In contrast, loading progressions for the knee and ankle should begin with the reverse lunge and progress to the forward lunge and then the single-legged squat.