Running: Soft or Hard Surface?

Edited By: Shai K.

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Anyone who runs regularly knows that there is no comparison between running on a hard surface, like a sidewalk, and running on a soft surface, like soil in nature or sand on the beach. Some might say that running on a soft surface is preferable, but is that really true? Indeed, our ancestors did not walk or run on paved sidewalks, and we tend to assume that what is natural is necessarily better for us, and indeed soil and grass are more natural than concrete. But when it comes to preventing injuries, is this assumption correct? We examined this issue in depth, and the answer is here before you.

What do studies say about running on a soft versus hard surface?

For decades, many people and experts in the field believed that hard surfaces lead to more injuries. The logic seemed simple: when you land on your foot while running, the force exerted is several times your body weight. On hard surfaces like a sidewalk, this force must be absorbed entirely by the muscles, tendons, ligaments, and bones. In contrast, softer surfaces like dirt trails were considered helpful in reducing the load.

But recent studies have begun to challenge this conventional belief. Studies analyzing large groups of runners have shown that running on soft surfaces does not significantly reduce the overall injury rate. In fact, the relationship between running surfaces and injury risk is more complex than previously thought.

What's Better for Running - Soft or Hard Surface: A Person Running on Sand

The Truth: Legs Adjust to Every Surface

The key to understanding this issue lies in how our body adapts to different running surfaces. When runners switch from a hard surface to a soft one, their body makes immediate adjustments. A study published in the Journal of Biomechanicsrevealed a fascinating phenomenon: runners actually reduce leg stiffness by more than 25% when switching from a soft to a hard surface.

Why does this happen? On soft surfaces, the runner’s center of gravity tends to shift backward due to the lack of stable support from the ground. To compensate for this and keep the body mass leaning forward, runners unconsciously increase muscle tension and leg stiffness. In contrast, hard surfaces provide better support, requiring less compensation from the muscles and leading to reduced leg stiffness.

All This Exposes Us to the "Soft Surface Paradox"

This situation creates what can be called the "Soft Surface Paradox":

Soft surfaces absorb more shock but require stiffer legs
Hard surfaces provide less cushioning but allow for looser legs
A stiffer leg can absorb less shock than a looser leg

A 2021 studyeven found higher acceleration in the shin bone when running on soft surfaces compared to hard ones, suggesting a potentially higher risk of injury. This is particularly relevant for certain groups of runners:

Older runners (over 40)
Runners with a history of Achilles tendon issues
Runners prone to calf muscle injuries

What's Better for Running - Soft or Hard Surface: People Running

So What Is the Recommended Surface for Running – Hard or Soft?

Despite researchers' findings, there is actually no clear recommendation one way or the other, and what’s advisable is simply to vary, sometimes preferring hard surfaces and sometimes soft. There are many advantages to this:

1. Increased Calorie Burn: Running on slightly soft surfaces like grass, sand, or trails can burn more calories because muscles work harder to maintain stability.

2. Full-Body Engagement: Different types of surfaces require varied involvement of the upper body, engaging the arms and shoulders.

3. Muscle Development: Different surfaces challenge the muscles in unique ways, potentially leading to better general strengthening of the muscles involved in running.

4. Training Variety: Choosing running routes with different surfaces naturally leads to discovering new trails, preventing boredom from running workouts, and increasing motivation to continue and persist.

Tips for Choosing the Right Running Surface for You

Based on recent research, here are some tips for those who run and want to get the most out of their workouts while avoiding injuries:

1. Don’t Run on Just One Type of Surface: Avoid running on only one type of surface, and if possible, incorporate multiple surface types into your workout.

2. Listen to Your Body: Pay attention to how different surfaces affect leg pain and muscle fatigue.

3. Consider Your History: If you have a history of Achilles tendon issues or calf muscle injuries, be cautious with soft surfaces like sand or grass.

4. Options for Different Running Surfaces: Try various surfaces such as sidewalks, running tracks, light gravel paths, hiking trails, short grass, beach sand.

What's Better for Running - Soft or Hard Surface: People Running on the Beach

Conclusion

While the common belief that soft surfaces prevent injuries did not stand up to scientific scrutiny, the relationship between running surfaces and injury risk is complex. Rather than focusing on finding the "perfect" running surface, one can benefit more from incorporating a variety of surfaces into their training and paying attention to how different surfaces personally affect their body.

The main takeaway is not that one surface is inherently good or bad, but that adaptation, variety, and individual response play a crucial role in injury prevention. As with many aspects of running, the best approach does not lie in absolute solutions but in finding what works best for one’s personal needs and circumstances.