The Acute Effects of Blood Flow Restriction on Ankle Muscle Reaction Time and Proprioception in Healthy Individuals

Lateral ankle sprains are among the most common musculoskeletal injuries and may lead to chronic ankle instability (CAI), partly due to impaired proprioception and neuromuscular control. Blood flow restriction (BFR) training is widely used to augment muscular adaptations with low external loads; however, its acute effects on joint proprioception and sensorimotor control, particularly at the ankle joint, remain unclear and may be detrimental under certain conditions. This randomized controlled crossover trial will examine the effects of a single-session lower limb BFR application on ankle joint position sense, kinesthesia, static and dynamic balance, and EMG-based reaction time and activity of lower limb muscles in healthy adults. Participants aged 18-40 years without recent ankle sprain, neuromuscular, cardiovascular, or thromboembolic disease will undergo standardized proprioception tests using an isokinetic dynamometer, static balance tests on a force platform, Y-balance test, and inversion simulation platform assessments under BFR (60% arterial occlusion pressure) and low-pressure control (20 mmHg) conditions. Individual arterial occlusion pressure (AOP) will be determined using Doppler ultrasound, and BFR will be applied with a pneumatic cuff at the most proximal thigh. All measurements will be performed on the dominant lower limb with sessions scheduled at the same time of day to minimize circadian variability. The primary hypothesis is that acute lower limb BFR will worsen ankle joint proprioception and sensorimotor control compared with the control condition, potentially indicating a transient increase in injury risk during BFR-assisted activities.