Your running style changes when you’re short of sleep
Get the Health newsletter
Daily health & science — research, biotech, public health, the studies worth knowing. Free.
- Maura Seynaeve at KU Leuven led a study finding sleep-deprived runners took 1–3 fewer steps per minute at the same speed and kept their feet on the ground longer, because they stiffen their leading leg less before impact.
- The experiment had 21 participants (11 women, 10 men) run twice on a treadmill a week apart — once after no sleep, once after normal sleep — with movements tracked by a waist-mounted accelerometer and motion-capture camera.
- Researchers found that while individual running styles vary too much to spot sleep deprivation in any random person from a single run, each runner showed significant biomechanical shifts between their two sessions.
- Sleep-deprived runners shifted toward a more 'grounded' running style, a gait sometimes recommended for injury-prone runners to reduce joint load — yet Seynaeve noted this may redistribute strain elsewhere, such as loading the knee more.
- Seynaeve hypothesized the mechanism is reduced alertness — runners are 'less present in the moment' and less able to actively prepare their legs for ground contact.
- A 2025 study cited by Seynaeve found runners who rated their sleep quality as poor were 36% more likely to be injured, a link she suggested could stem from these altered load patterns.
- Hannah Dimmick at the University of Denver called the study 'very well-designed and executed' but said fatigue and sleep deprivation aren't directly comparable, and floated future research into whether sleep loss exaggerates acute fatigue's biomechanical effects.
Why it matters: The study offers a concrete biomechanical mechanism linking poor sleep to running injuries: cadence drops by 1–3 steps per minute and gait shifts toward a grounded style that may redistribute load onto joints like the knee. For the millions of runners who train on limited sleep, the research reframes injury prevention as partly a sleep-quality problem — not just a form or mileage one.
Ask SkimNews
