Acute Effects of an Elastic Toe-Tube Exercise on Intrinsic Foot Muscle Size and Reactive Strength in Healthy Young Men: A Randomized Crossover Study
Yuki Nakai, Yasufumi Takeshita, Makoto KomiyaBackground
Intrinsic foot muscles (IFMs) contribute to plantar stiffness regulation and force transmission during dynamic tasks. Although the short-foot exercise (SF-ex) is commonly prescribed to strengthen IFMs, its immediate effects on muscle morphology and reactive performance remain unclear.
Purpose
To examine the acute effects of an elastic toe-tube exercise (Tube-ex) on IFM cross-sectional area (CSA) and reactive strength compared with SF-ex and a control condition.
Study Design
Randomized crossover study.
Methods
Twenty healthy recreationally active young men completed three conditions (Tube-ex, SF-ex, and control) in randomized order with a washout period of at least one week. Ultrasound-derived CSA of the abductor hallucis, flexor hallucis brevis, and flexor digitorum brevis was assessed before and immediately after each condition. Reactive performance was evaluated using the reactive strength index (RSI) obtained from repeated rebound jump tests. Two-way repeated-measures analysis of variance was used to examine time × condition effects.
Results
Significant time × condition interactions were observed for all IFMs (p ≤ 0.019, partial η² = 0.21–0.61), with the greatest increases following Tube-ex (approximately 6–13%). CSA changes exceeded minimal detectable change thresholds after Tube-ex. A significant interaction was also found for RSI (p = 0.035, partial η² = 0.16), with improvement observed only after Tube-ex (Cohen’s d = 0.66–0.80).
Conclusion
Tube-ex elicited greater acute increases in IFM size and reactive strength than SF-ex and control. These findings support its potential as a practical neuromuscular priming strategy for athletic preparation and early-stage rehabilitation.
Level of Evidence
Level 2