Ankle mobility, in particular dorsiflexion, is an essential mobility need for athletics and every day activities including stair climbing and squatting. Interestingly, authors have shown side to side asymmetries of 6 degrees, > 20% were greater than 10 degrees, are common between legs in both healthy and injured populations Prior research has demonstrated altered dynamic alignment of the leg during functional tasks such as the squat and step down. When the ankle has reached its’ limits of mobility the shin begins to move inward (knee valgus) as the body borrows motion from adjacent areas. Interestingly, subsequent research has shown when restricted individuals are given range of motion, heel lift, there mechanics improve during these tests. This is something experienced weight trainers have known for a long time and often can be seen utilizing weight plates under their heels during the squat exercise to improve their depth and/or mechanics. A recent study examined how force production is altered in the presence of ankle restrictions.
Crowe and colleagues in the Journal of Strength and Conditioning Research assessed healthy, trained individuals biomechanics and force production during the squat in the presence of ankle mobility restrictions (2020). To be included subjects must have less than 5 degrees difference between their ankles. Individuals were assessed in a barefoot condition as well as with a 10 degree wedge under their foot to create a relative/simulated ankle restriction. Authors reported improved mechanics and force production in the unrestricted limb compared to the “restricted” ankle. Although this study artificially created an ankle restriction these findings are plausible based on our clinical observations and prior research results.