Limitation of ankle motion is in many cases treated by joint mobilization (JM), a kind of manual physical therapy technique. Until now, the JM approach has mainly focused on the talocrural joint, with less attention to the distal tibiofibular joint. This study applied cyclic loading to the lateral malleolus as in JM in order to clarify the relationship between the dorsiflexion angle and the excursion of the lateral malleolus. Seven normal, fresh-frozen cadaver legs were used. To each specimen, cyclic loading with a 30 N force was applied 1000 times to the lateral malleolus at a speed of 15 N/s. The displacement of the lateral malleolus was measured with a magnetic tracking system. The maximum dorsiflexion angle was measured before and after cyclic loading. After the first 100 and 1000 times of cyclic loading, the tibia was displaced 0.44 ± 0.30 mm and 0.75 ± 0.36 mm, respectively, and the fibula was displaced 0.44 ± 0.28 mm and 0.92 ± 0.39 mm, respectively. The average dorsiflexion angle increased from 14.36 ± 7.51° to 16.74 ± 7.21° after cyclic loading (P < 0.05).
Movement of the distal tibiofibular joint led to a significant increase in the range of ankle dorsiflexion. These results suggest that tibiofibular JM would be effective for limitation of ankle dorsiflexion.