Running Surfaces: Why Sidewalks Are Suboptimal and What to Choose Instead

Are Runners Supposed to Run on the Sidewalk?

While sidewalks offer convenient access and separation from traffic, they are generally not the optimal surface for regular running due to their unforgiving hardness and uniform rigidity, which can increase impact forces on the musculoskeletal system.

Understanding Running Surface Biomechanics

Every time your foot strikes the ground while running, your body absorbs a "Ground Reaction Force" (GRF). This force is directly influenced by the hardness of the surface. Harder surfaces, such as concrete sidewalks, offer minimal shock absorption, meaning a larger percentage of the GRF is transmitted up through your kinetic chain—from your feet and ankles to your knees, hips, and spine.

Your body possesses natural shock absorbers, including the arches of your feet, the cartilaginous structures in your joints (like the menisci in the knees), and the muscular system. However, repetitive high-impact forces on unyielding surfaces can overwhelm these natural mechanisms, leading to increased stress on bones, tendons, ligaments, and muscles. Softer surfaces, conversely, deform slightly upon impact, dissipating some of the GRF and reducing the load on your musculoskeletal system.

The Perceived Benefits of Sidewalk Running

Despite their biomechanical drawbacks, sidewalks remain a popular choice for many runners, primarily due to:

• Safety from Vehicular Traffic: Sidewalks provide a dedicated pedestrian zone, significantly reducing the risk of collisions with cars, cyclists, or other motorized vehicles.
• Accessibility and Convenience: In urban and suburban environments, sidewalks are ubiquitous, offering readily available routes close to homes and workplaces.
• Predictable Surface: Unlike trails or uneven roads, sidewalks typically offer a consistent, flat, and obstruction-free path, reducing the risk of tripping over roots, rocks, or potholes.

The Downsides: Why Sidewalks Are Suboptimal

While safety and convenience are undeniable, the disadvantages of concrete sidewalks for regular running are significant from an exercise science perspective:

• High Impact Forces: Concrete is one of the hardest running surfaces. Each stride generates a significant GRF that must be absorbed by the runner's body. This repetitive, high-magnitude impact can contribute to overuse injuries.
• Increased Risk of Repetitive Stress Injuries (RSIs): The constant, unyielding impact on concrete can exacerbate or cause RSIs such as:
  • Shin Splints (Medial Tibial Stress Syndrome): Inflammation of the connective tissue surrounding the tibia.
  • Stress Fractures: Microscopic cracks in bones, often in the tibia, fibula, or metatarsals.
  • Patellofemoral Pain Syndrome (Runner's Knee): Pain around or behind the kneecap.
  • Achilles Tendinopathy: Inflammation or degeneration of the Achilles tendon.
  • Plantar Fasciitis: Inflammation of the thick band of tissue on the bottom of the foot.
• Lack of Varied Stimuli: The uniform rigidity of sidewalks provides very little variation in ground contact. This can lead to a repetitive loading pattern that doesn't adequately challenge or strengthen the smaller stabilizing muscles responsible for proprioception and balance, which are crucial for injury prevention.
• Lateral Camber/Sloping: Many sidewalks are constructed with a slight lateral slope (camber) to facilitate water drainage. Running consistently on a sloped surface can create an uneven loading pattern, stressing one side of the body more than the other, potentially leading to imbalances and injuries in the hips, knees, and ankles.

Optimal Running Surface Alternatives

For runners seeking to minimize impact and promote long-term musculoskeletal health, several surfaces are generally preferred over concrete sidewalks:

• Asphalt Roads: While still hard, asphalt is typically more forgiving than concrete. It has a slightly more elastic quality due to its aggregate and binder composition, allowing for a marginal degree of shock absorption.
• Running Tracks (Synthetic): Modern synthetic tracks are engineered specifically for running, offering excellent cushioning and consistent footing. They are ideal for speed work, interval training, and for runners seeking a predictable, low-impact surface.
• Trails (Dirt/Gravel): Natural trails offer significant advantages. The varied terrain (roots, rocks, slight inclines/declines) engages a wider range of muscles, enhances proprioception, and the natural give of dirt and packed earth provides superior shock absorption. However, they require increased vigilance to prevent falls.
• Grass: Grass is an excellent low-impact surface, offering superb shock absorption. It's great for barefoot running drills or easy recovery runs. Caution is advised to ensure the grass is free of hidden hazards like holes or sharp objects.
• Treadmills: Treadmills provide a controlled environment with adjustable cushioning (depending on the model) and the ability to control speed and incline precisely. They are a good option for mitigating impact, especially for those with injury concerns or during inclement weather.

Making an Informed Choice: Factors to Consider

The "best" running surface isn't universal; it depends on individual factors:

• Training Volume and Intensity: Higher mileage and more intense workouts demand surfaces that offer better shock absorption.
• Injury History: Runners with a history of stress fractures, shin splints, or joint pain should prioritize softer surfaces.
• Footwear: While proper running shoes provide cushioning and support, they cannot fully negate the impact of extremely hard surfaces like concrete over long distances or high volumes.
• Running Form: While efficient running mechanics can help distribute impact forces, even perfect form won't eliminate the inherent hardness of concrete.
• Individual Tolerance: Some runners may tolerate harder surfaces better than others due to genetic factors, muscle strength, or adaptability. Listen to your body's feedback.
• Workout Type: Short, fast intervals might be acceptable on a track or even a sidewalk if you warm up properly and cool down, but long, slow distance runs are best performed on softer, more forgiving surfaces.

Mitigating Risks When Sidewalks are Your Only Option

If your access to alternative running surfaces is limited and sidewalks are your primary option, you can take steps to minimize the associated risks:

• Vary Your Route and Direction: If possible, alternate the direction you run on a sidewalk to counteract the effects of camber. Seek out sections that might have slightly different paving materials or less slope.
• Incorporate Cross-Training: Supplement your running with non-impact activities like cycling, swimming, elliptical training, or rowing. This reduces your overall running volume and the cumulative impact on your joints.
• Prioritize Strength Training: A strong core, glutes, and lower body muscles (hips, quads, hamstrings, calves) improve your body's natural ability to absorb shock and maintain stability, reducing stress on passive structures like bones and ligaments.
• Invest in Proper Footwear: Choose running shoes with adequate cushioning appropriate for your foot strike and biomechanics. Replace your shoes regularly (typically every 300-500 miles or 4-6 months, depending on use) as cushioning degrades over time.
• Listen to Your Body: Pay close attention to any persistent aches or pains. Do not try to "run through" pain. Implement rest days, reduce mileage, or seek professional advice if discomfort persists.
• Focus on Running Form: While not a complete solution, maintaining an efficient running form with a slightly higher cadence (shorter, quicker steps) and landing softly with your foot under your center of gravity can help reduce peak impact forces.

Conclusion

While sidewalks offer a convenient and safe separation from traffic, they are not the ideal surface for consistent, high-volume running due to the high impact forces concrete transmits to the musculoskeletal system. For optimal long-term joint health and injury prevention, runners are encouraged to seek out softer, more forgiving surfaces like asphalt roads, synthetic tracks, dirt trails, or grass whenever possible. When sidewalks are unavoidable, strategic cross-training, consistent strength work, proper footwear, and attentive listening to your body become even more critical to mitigate the inherent risks.