Author(s): EDGINGTON, H., LAMBERT, A., MCMANUS, C., LIEW, B., Institution: UNIVERSITY OF ESSEX, Country: UNITED KINGDOM, Abstract-ID: 604

INTRODUCTION:
Blood flow restriction (BFR) training has gained increasing interest as a technique to enable muscular adaptations at lower training loads. It has been thought to be a safer training method when high training loads are contraindicated, such as during injury rehabilitation (1). However, it is unclear how BFR impacts proprioception, which is crucial for joint stability and function. Joint proprioception relies on mechanoreceptors that may be affected by tissue hypoxia induced by BFR. This study aims to explore the effects of BFR on ankle proprioception, contributing valuable insights for rehabilitation and performance enhancement.
METHODS:
Twenty-one participants were divided into three intervention groups: control (n=5), sham BFR (n=8), and BFR (n=8) groups. Joint position sense (JPS) was assessed using a passive-passive test on an isokinetic dynamometer. Participants’ ankles were plantarflexed to a “target angle” of 20°, then moved from 0° to 40° of plantarflexion, stopping when participants felt the target angle was “matched”. Ten matching trials were performed. The JPS test was performed before, during, and after the intervention. For the BFR group, a cuff was applied with 80% limb occlusion pressure at the mid-thigh, while for the sham group, the same cuff was applied with minimal pressure (2-5mmHg) (1). A linear mixed model analysis was used to evaluate the effect of the intervention on the outcome of JPS error (match-target).
RESULTS:
No significant differences were observed between BFR and Control (Estimate =1.64, 95% CI [-4.31,7.53], p = 0.995), between BFR and Sham (Estimate = 2.21, 95% CI [-3,7.43], p = 0.892) and Sham and Control (Estimate = -0.58, 95% CI [-6.52,5.37], p = 0.995) during the intervention. This trend was similarly observed before and after the intervention.
CONCLUSION:
The study demonstrated that BFR does not impair ankle JPS. This outcome might be attributed to using a passive JPS test, where the demand for blood flow is less critical than in active tests (2). Passive tests involve lower levels of capillary recruitment, blood flow demand, muscle pump activation, and autonomic response compared to active tests (2). The restricted blood flow during BFR might be sufficient for the normal functioning of the mechanoreceptors, hence preserving normal JPS. Confirming that BFR does not impair proprioception supports its broader use in rehabilitation, potentially improving outcomes by enhancing muscle strength without impairing normal joint function. These findings pave the way for further research to refine BFR training for diverse populations, contributing to developing guidelines that maximise its benefits while ensuring safety and effectiveness.

References:
1. Patterson et al., Frontiers in physiology, 2019, DOI: 10.3389/fphys.2019.00533
2. Trinity et al., Sports Medicine, 2019, DOI: 10.1007/s40279-019-01146-1