Effects of a foot strengthening program on foot muscle morphology and running mechanics: A proof-of-concept, single-blind randomized controlled trial.

This small proof-of-concept trial looked at whether an 8-week foot strengthening program could change the size of the tiny muscles inside the foot and also affect running mechanics. Twenty-eight recreational runners who weren't used to barefoot or minimalist running were split into a group that did the foot exercises and a control group that didn't. The researchers measured things like toe and hallux (big toe) strength, the size and volume of four small foot muscles using imaging, how the foot's arch moved and stiffened, and the forces runners produced when pushing off the ground. After 8 weeks, the exercise group showed increases in the volume of all four foot muscles studied compared to the control group, along with a bigger vertical propulsive impulse, which is essentially the upward push-off force during running.

The researchers also found that bigger muscle volume was linked to a stronger push-off force, with the flexor digitorum brevis showing the strongest connection of the muscles measured. The authors describe this as evidence that intrinsic foot muscle strengthening can influence running mechanics, and they raise the possibility that it might relate to running performance, though that link wasn't directly tested here. As a proof-of-concept study with a small sample, this is best seen as an early signal rather than a settled answer about performance effects.

This study asked whether doing specific exercises to strengthen the small muscles inside your foot could actually change those muscles and how your foot behaves when you run. Twenty-eight recreational runners took part, with half doing an 8-week foot muscle training program and half not doing it, so the researchers could compare the two groups afterward. The group who did the foot exercises saw their intrinsic foot muscles (the ones inside your foot that support the arch and toes) grow larger, and they also produced more upward push-off force when running compared to the group that didn't train.

The researchers also noticed that runners with bigger foot muscles tended to have stronger push-off forces, suggesting these two things might be connected, though this doesn't prove one caused the other. What's still unclear is whether these muscle and mechanical changes actually translate into better running performance, less injury risk, or any noticeable difference in how a run feels day to day. This was a small study designed to test whether the idea works at all, not a large trial confirming real-world benefits.

It gives an interesting early look at how foot exercises might influence running mechanics, but more research would be needed before drawing firm conclusions about what this means for runners generally.

This is a summary of research, not medical advice. Talk to your own healthcare provider about anything affecting your care.

This was a proof-of-concept, single-blind RCT with 28 recreational runners, so the primary value here is establishing that an 8-week intrinsic foot muscle program can produce measurable changes in muscle morphology and running biomechanics, rather than confirming clinical or performance benefits. The intervention group showed increased cross-sectional volume across all four intrinsic muscles assessed (abductor hallucis, abductor digiti minimi, flexor digitorum brevis, and flexor hallucis brevis) relative to controls, alongside an increase in vertical propulsive impulse during running. Correlations between muscle volume and vertical propulsive impulse were moderate for abductor hallucis (r = 0.40) and abductor digiti minimi (r = 0.41), and stronger for flexor digitorum brevis (r = 0.69), suggesting some muscles may be more mechanically relevant to push-off force than others, though correlation doesn't establish causation.

Medial longitudinal arch range of motion and stiffness were also assessed, but the abstract doesn't report significant between-group findings for these, which is worth noting when interpreting the overall picture. Given the small sample and short intervention window, these findings function as an early signal that intrinsic foot training can alter both structure and loading mechanics in runners, rather than as evidence of improved running economy, injury reduction, or performance outcomes. Larger trials with performance and injury endpoints would be needed to determine whether these morphological and mechanical changes carry through to meaningful clinical outcomes.