Let’s talk about running! I am an avid runner who enjoys racing and, more importantly, training with friends. After years of living in the city, running on pavement was all I knew. It wasn’t until moving back to the Hudson Valley in 2017 that I discovered my love for the trails. Fortunately, here in the Tri-State area, we are surrounded by an abundance of beautiful and runnable hiking trails.

The International Trail Running Association defines a trail race as an endurance race set in a natural environment with varying off-road terrains, such as mountains, forests, countryside, or deserts, often with significant elevation gains and loss from start to finish, and with a maximum of 20% of the total route run on paved road. While research has shown that trail running has proven mental and physical health benefits, high injury risks remain.

Common Trail Running Injuries

The lower extremity, which includes the leg, ankle, and foot, is the most common region for acute and chronic injuries seen in trail runners, with ankle sprains being the most common acute injury. Chronic and overuse injuries include:

• Tendinopathies (Achilles, hamstring).
• Joint sprains (ankle sprains).
• Soft tissue injuries (muscle strains, ITB syndrome, patellofemoral pain syndrome, plantar fasciitis).
• Stress fractures (foot, shin bone).

Mechanisms of Injury

Runners face different physical challenges when trail running, including avoiding obstacles and adjusting to various elevation gains and ground terrain. Runners need anticipatory, predictive, and reactive balance control strategies to maintain stability when negotiating the environment around them. In order to avoid potential injury, these challenges require adequate dynamic muscle strength and neuromuscular control, as well as normal lower extremity joint motion and loading.

Lower extremity muscle strength deficits can result in fatigue when trail running. This fatigue can translate into altered trail running mechanics, leading to movement errors, asymmetry, and a disruption of the normal force transmission at the knee, calf, ankle, and foot when running. Inadequate strength and neuromuscular control of these repetitive impact forces are common causes of musculoskeletal pain and injury in trail runners. Similarly, trail runners with chronic pain can demonstrate altered running mechanics through compensatory movements in an effort to avoid pain. These compensations can disrupt normal loading and result in secondary pain in other parts of the body. Abnormal joint motion can also alter a runner’s gait mechanics and lead to injury due to excessive or inadequate joint movement.

Injury Prevention

Injury prevention should be incorporated into all training programs for trail runners and include education and plyometric, flexibility, neuromotor control, and strength training exercises.

Concerning education, Vincent et al. provide four key rules to avoid serious injury:

• Immediately stop running if pain increases during a run or changes in quality from achy to sharp.
• Joint pain should not last longer than 24 hours (may indicate volume was too much).
• If there is preexisting pain (less than 3/10 on the pain scale), it should not increase or continue into the next day.
• You should stop running until pain-induced compensation disappears.

Flexibility exercises, including dynamic warm-ups, should be incorporated into training to help decrease the risk of lower extremity and back injuries. Strengthening the kinetic chain from the foot through the trunk, neuromotor control, and plyometric exercises are also crucial for injury prevention. Muscle strength deficits and imbalances have been attributed to a variety of injuries. For example, hip abduction weakness has been linked to ITB syndrome, a common injury among trail runners. Another training technique that has been found to reduce the risk of injury includes increasing and maintaining a balanced hamstrings and quadriceps strength ratio. Likewise, athletes with increased gluteal, back, and abdominal muscle activation have been shown to have fewer hamstring injuries than those with decreased muscle activation. Furthermore, adequate quadriceps and lower extremity strength are especially important for navigating uphill and downhill trails.

Foot strengthening is often overlooked but is equally important when considering injury prevention. Strengthening the foot muscles can improve ankle control, which is vital for stability and responsive accommodation to course obstacles and terrain changes. Strengthening the intrinsic foot muscles can also enhance force transmission through the foot and help control the initial impact loading of the foot. Neuromuscular control exercises for the trunk, lower extremity, and foot are essential to maintain stability, balance, and coordination. Plyometrics are also crucial for knee injury prevention. Studies have shown that plyometric exercises can reduce ground reaction forces by 17-26% over 6-9 weeks.

Rehab

So what happens if you end up getting injured? Rehabilitation for trail runners focuses on 1) symptom management and load reduction, 2) recovery, 3) rebuilding, and 4) return to sport. The recovery timeline will vary in severity and type of injury. Bone stress injuries (foot, shin, thigh bone) will require relative or total unloading anywhere from 6-24 weeks, with gradual reloading and strength building, balance, and neuromuscular control training. High-risk stress fractures that could potentially lead to delayed healing or non-union may require non-weight bearing and/or immobilization and surgery. Rehab for chronic soft tissue injuries (such as patellofemoral pain or ITB syndrome) can be managed with therapy. These injuries typically have much shorter recovery time frames and often depend on the runner’s pain.

Closing Thoughts

Whether you’re training for a race or simply enjoy getting out on the trails, I would encourage you to seek guidance from a professional (such as a PT) to start an injury prevention training program. If you sustain an injury, know that recovery is possible and that Iron Health is here to help you get back on the trails!

References:

Discover trail running. International Trail Running Association. Accessed April 24, 2023. https://itra.run/About/DiscoverTrailRunning

Vincent HK, Brownstein M, Vincent KR. Injury Prevention, Safe Training Techniques, Rehabilitation, and Return to Sport in Trail Runners. Arthrosc Sports Med Rehabil. 2022;4(1):e151-e162. Published 2022 Jan 28. doi:10.1016/j.asmr.2021.09.032