Get access to everything we publish when you sign up for Outside+.
Athletes tend to think of injuries as isolated incidents: Five hours on the bike equals lower back pain, or extra yardage in the pool is to blame for a case of swimmer’s shoulder. But injuries are often the sum of all stress placed on the body. According to chiropractic sports physician John Ball, poor sleep position can be a major contributor to the injury equation.
“People think of sleep as a passive activity: lie down, close your eyes, and wake up eight hours later, ready for the world,” Ball says. “In reality, sometimes the way you’re draping that leg across your body and off the bed, or holding your arm under the pillow, can often be the final factor that pushes you over the edge of injury or keeps you from recovering fully.”
Positioning the arm under the head holds the shoulder muscles on the extreme end of their range of motion, increasing risk of impingement.
Draping one leg over the other twists the pelvis and lower back, stretching the hip musculature for extended periods of time. Favoring one side can also contribute to muscle imbalances.
Turning your head to the side to breathe is a necessity, but it’s also a hazard, contributing to stiffness and neck pain.
Stomach sleeping, especially on softer beds, can hyperextend the low back, setting the stage for discomfort on the bike and run.
Plantar flexion, or “pointed toe” position, can contribute to plantar fasciitis or Achilles tendinopathy.
People gravitate toward the position that they’re most comfortable in, but the body can be “trained.” Ball suggests small changes—a pillow between the knees to keep the pelvis stacked, or repositioning the arm upon waking—over drastic changes, which may detract from overall sleep quality.