One Night of Acute Sleep Deprivation Alters Running Biomechanics and Running Economy in Recreational Runners

PURPOSE: This study examined the effects of one night of sleep deprivation on lower-limb biomechanics and running economy while running at different intensities. METHODS: Sixteen healthy recreational runners (7 male, 9 female) completed a randomized crossover study comparing one night of total sleep deprivation (SDEP) with normal sleep (CON). In each condition, participants completed submaximal treadmill running at intensities corresponding to 90% LT1, LT1, and 90% LT2, followed by a fourth interval to exhaustion at LT2. Spatiotemporal, kinematic, and kinetic data were collected using an instrumented treadmill and 3D motion capture, while metabolic rate was assessed via indirect calorimetry. RESULTS: Sleep-deprived subjects were running with a lower cadence (p=.030), longer ground contact time (p<0.001), and higher duty factor (p=0.012). Peak vertical ground reaction force and loading rate were reduced in SDEP (p=0.002 and p=0.011). Knee flexion angle and peak knee extensor moment during the stance phase were larger in SDEP (p=0.015 and p=0.037). Average positive knee power increased in SDEP (p=0.019), while average positive ankle power decreased in SDEP (p =0.019). SDEP also led to a decrease in leg stiffness (p=0.028). Gross metabolic power was significantly reduced in SDEP compared to CON, suggesting improved running economy (p<0.001). Time to exhaustion during the last running interval was reduced by 13.2% in SDEP compared to CON (p=0.023). CONCLUSIONS: Sleep deprivation increased duty factor, shifted joint contributions from distal to proximal muscles and reduced leg stiffness while also reducing gross metabolic power at a given speed. Despite these efficiency gains, participants fatigued more quickly at their second lactate threshold.