Differences in Static- and Dynamic-Balance Task Performance After 4 Weeks of Intrinsic-Foot-Muscle Training: The Short-Foot Exercise Versus the Towel-Curl Exercise

CONTEXT: Proper functioning of the intrinsic foot musculature (IFM) is essential in maintaining the integrity of the medial longitudinal arch (MLA). Improper functioning of the IFM leads to excessive pronation of the foot, which has been linked to various pathologies. Therefore, training the IFM to avoid excessive pronation may help prevent some of these pathologies; however, it is not clear how to train these muscles optimally. OBJECTIVE: To investigate the effects of 2 different types of IFM training on the height of the MLA and static- and dynamic-balance task performance. DESIGN: Randomized controlled trial, repeated-measures mixed-model design. SETTING: University biomechanics laboratory for testing and a home-based training program. PARTICIPANTS: 24 healthy, university-age volunteers (3 groups of 8) with no history of major lower limb pathology or balance impairment. INTERVENTIONS: One experimental group performed 4 wk of the short-foot exercise (SFE) and the other performed 4 wk of the towel-curl exercise (TCE). Participants were asked to perform 100 repetitions of their exercise per day. MAIN OUTCOME MEASURES: Navicular height during weight bearing, the total range of movement of the center of pressure (COP) in the mediolateral (ML) direction for a static-balance test and a dynamic-balance test. RESULTS: There were no differences in the navicular height or static-balance tests. For the dynamic-balance test, all groups decreased the ML COP movement on the dominant limb by a small amount (~5 mm); however, the SFE group was able to decrease COP movement much more than the TCE group in the nondominant limb. CONCLUSIONS: The SFE appeared to train the IFM more effectively than the TCE; however, there were differing results between the dominant and nondominant legs. These imbalances need to be taken into consideration by clinicians.