The Effects of External Lower Limb Weight or Pressure Application on Human Knee Joint Proprioception in Resting and Fatigue Conditions: A Randomized Trial.

Objectives: Knee proprioception is affected by many biomechanical and physiological factors. Often, during training, rehabilitation, or specific sport requirements, weight or pressure is applied to the foot. However, it is not clear if such applications affect knee proprioceptive acuity. This study examined whether the application of an external weight (3 kg) or of pressure (120 mmHg) at a level above the ankle joint would affect knee proprioception in an open kinematic chain movement in resting or fatigue conditions. Methods: Participants included active young men (n = 7) and women (n = 15), aged 21-34 years, without prior knee injury. Women were tested in their follicular phase. An isokinetic dynamometer was used to evaluate knee joint repositioning. Three knee angles were targeted (30°, 45°, 60°) before and after localized muscle fatigue. A three-way ANOVA analysis with repeated measures and one independent variable (gender) was performed. Results: Analysis showed that ankle weight application positively influenced knee joint proprioceptive acuity resulting in an overall reduction in knee joint angular error for both genders, with the "corrective" effect most evident at 45° and 60° knee joint angles (p < 0.05), whether in the rested or fatigued state. The application of pressure however improved knee proprioceptive performance in men (p < 0.05), in both the rest and fatigue states, but not in women (ns tendency). Conclusions: Application of a small weight at the ankle level significantly improved proprioceptive knee joint acuity. These findings may have wider applicability by allowing the development of specific preventive measures towards safeguarding weaker and/or less resilient players.