One Foot Exercise That Improves Balance in Trail Runners

Trail running means constantly working with complex terrain: rocks, roots, slopes. Your foot must instantly adapt to every irregularity. But most runners train their legs "top-down" — quads, calves, glutes. What about the muscles of the foot itself?

New research from Chile and Spain, published in PeerJ (November 2025), shows: one simple exercise can significantly improve balance and arch stability in trail runners.

What They Studied

Researchers from Universidad Austral de Chile and Universidad de Valencia recruited 16 experienced trail runners (average age 36 years, 50% female) and tested the effect of Short Foot Exercise (SFE) — an exercise for activating the intrinsic foot muscles.

Protocol:

• 3 sets of 12 repetitions
• Each contraction — 5 seconds
• Rest between sets

Before and after the exercise, they measured:

• Y-Balance Test — dynamic stability in three directions
• Arch Height Index — arch height through 3D motion capture

Results

After a single SFE session, runners showed significant improvements in balance scores across all Y-Balance Test directions.

Interestingly, the effect on arch height varied. Runners with higher weekly training volumes showed more pronounced increases in anterior arch height.

The authors conclude: even a single SFE session can acutely improve dynamic balance — a critically important skill for running on uneven terrain.

What Is Short Foot Exercise

SFE is an isometric contraction of the intrinsic foot muscles without toe flexion.

How to Perform:

1. Starting position: Sit on a chair, foot flat on the floor, toes relaxed
2. Movement: Try to "shorten" the foot by pulling the base of the big toe toward the heel
3. Important: Toes do NOT curl or lift off the floor — only the arch works
4. Hold: 5 seconds
5. Repetitions: 12 times × 3 sets

Visually, the arch should rise slightly and the foot become "shorter." If your toes curl — you're doing it wrong.

Progression:

• Week 1–2: Seated on a chair
• Week 3–4: Standing on both feet
• Week 5+: Standing on one foot

Why It Works

The foot contains numerous small muscles that:

• Support the arch
• Stabilize joints during ground contact
• Transmit sensory information about the surface

In modern humans, these muscles are often weakened due to:

• Supportive footwear
• Walking on flat surfaces
• Sedentary lifestyle

SFE "wakes up" these muscles and improves their ability to react quickly — exactly what you need on technical trails.

Practical Recommendations

When to Do It:

• Before trail workouts — as part of warm-up for foot activation
• On recovery days — for strengthening without load
• After ankle injury — for rehabilitation (consult your doctor)

Integration into Training:

Minimal option:

• 3×12 repetitions before each trail workout
• Time: ~5 minutes

Extended option:

• SFE 3×12
• • Calf raises 2×15
• • Single-leg balance 2×30 seconds
• Time: ~10 minutes

Study Limitations

Important context:

1. Small sample — 16 people. Larger studies needed
2. Acute effect — measured immediately after exercise. Long-term effect not studied
3. Proof-of-concept — authors themselves call this a preliminary study

Nevertheless, results are consistent with previous SFE research on other populations.

Key Takeaways

• Short Foot Exercise — a simple exercise for activating intrinsic foot muscles
• New research showed acute balance improvement in trail runners after one session
• Technique: Shorten the foot without curling toes, 3×12 for 5 seconds each
• Application: Before trail workouts as part of warm-up

Five minutes — a small investment for potentially improved stability on technical terrain.

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Source: Aguilar-Risco C. et al. "Acute effect of short foot exercise on dynamic stability and foot kinematic in trail runners: a proof-of-concept study." PeerJ, November 2025. DOI: 10.7717/peerj.20364