The influence of knee injuries on ankle plantarflexion and dorsiflexion strength

Purpose: Knee joint injuries may affect the function of the adjacent ankle joint. The strength of ankle dorsiflexion and plantarflexion of the affected leg, was compared to the unaffected leg, to assess the influence of different knee injuries on ankle movement strength. Methods: Sixteen healthy, young adult males with a mean age of 34 years, and a unilateral knee injury (either the menisci, the ligaments, or both) were examined To measure the dorsiflexion strength, the Elgin ankle exercise machine was used, and for measuring the plantarflexion strength, heel raise exercises with full body weight was performed by the participants. The one repetition maximum (1RM) of both the injured and non-injured legs, was calculated through the Epley equation using the repetition until fatigue method. Results: There was no evident difference found in the strength of dorsiflexion between the injured and non-injured legs. However, there was a significant difference among the plantar flexion strength of the injured and non-injured legs. Conclusion: Injury at the knee joint affects the strength of the muscles at the adjacent ankle joint, especially the plantarflexion. Therapists treating these types of patients, must attend to the ankle deficits caused as a result of knee.