Hypoalgesic effects of a blood flow restriction technique at moderate intensity with or without motor imagery: a single-blind randomized controlled trial.

PURPOSE

The main objective was to assess the hypoalgesic effect of adding blood flow restriction (BFR) training with or without motor imagery (MI) to moderate-intensity exercise. The secondary objective was to analyse the correlations of the pain pressure thresholds (PPTs) regarding perceived pain intensity, perceived fatigue, and cuff pressure discomfort.

METHODS

A sample of 42 asymptomatic participants were randomly assigned to 3 groups: control group (CG), BFR group, and BFR with MI group. All participants performed a squat exercise at an intensity of 60% of 1RM. For the BFR groups, blood occlusion occurred at 80% of maximal arterial occlusive pressure. Local, bilateral, and distal PPT were assessed pre-intervention, post-intervention and 48 h post-intervention. The perceived fatigue was assessed post-intervention, and pain intensity was assessed only 48 h post-intervention.

RESULTS

There were intragroup differences in the CG and BFR + MI group in the local PPT between the pre-intervention and post-intervention measurements ( = 0.039, = -0.32 and  = 0.009, = -0.46, respectively) and only in the CG in the bilateral PPT ( = 0.002, = -0.41). The CG and BFR group showed significant differences at 48 h post-intervention, with a decrease in local PPT ( = 0.009,  = 0.51 and  = 0.049,  = 0.43, respectively) and bilateral PPT ( = 0.004,  = 0.53 and  = 0.021,  = 0.46, respectively). There was a negative moderate correlation between local PPT at the post-intervention time and perceived discomfort of the occlusion device only in the BFR group (=-0.54,  = 0.045).

CONCLUSION

Moderate-intensity resistance training with high occlusion did not generate hypoalgesia but did appear to generate a hyperalgesic response within 48 h after the intervention.