Effects of Toe Tube Training on Intrinsic Foot Muscle Strength and Reactive Strength Index in Runners: A Randomized Controlled Trial

Abstract

Long-distance runners are known to be at a high risk of lower limb disorders due to a decline in the function of the intrinsic foot muscles (IFMs). The aim of this study was to examine the effects of toe tube training using elastic tubes. First, a crossover study was conducted with 13 healthy adults in three conditions: tube training, short foot exercise, and control. Changes in the IFMs pre- and post-exercise were confirmed using ultrasound echo. Next, 19 university long-distance runners were randomly divided into two groups (tube training or short foot exercise) and underwent a five-week training intervention. The toe grip strength, toe gap strength, and reactive strength index were measured pre- and post-intervention. In a crossover study, the tube training and short foot exercise showed a significant interaction effect on the abductor hallucis brevis (F = 5.63, p = 0.010, partial η2 = 0.32) and flexor digitorum brevis (F = 15.29, p < 0.001, partial η2 = 0.56), confirming an immediate effect of tube training and short foot exercise. In an intervention study with runners, no interaction was observed but a main effect of time was found, with both groups showing significant improvements in toe grip strength (F = 25.64, p < 0.001, partial η2 = 0.60), toe gap strength (F = 11.26, p = 0.004, partial η2 = 0.40), and RSI (F = 4.81, p = 0.042, partial η2 = 0.22). Tube training may be an effective alternative for runners who find short foot exercise difficult and want to adjust the exercise load.