The acute muscular response to passive movement and blood flow restriction

Purpose To compare the acute effects of passive movement combined with blood flow restriction (PM + BFR) to passive movement (PM) or blood flow restriction alone (BFR). Methods A total of 20 healthy participants completed: time control (TC), PM, BFR and PM + BFR (one per leg, over 2 days; randomized). For PM, a dynamometer moved the leg through 3 sets of 15 knee extensions/flexions (90° at 45°/second). For BFR, a cuff was inflated to 80% arterial occlusion pressure on the upper leg. Measurements consisted of anterior muscle thickness at 60% and 70% of the upper leg before and after (−0, −5 and −10 min) conditions, ratings of perceived effort and discomfort before conditions and after each set, and of the vastus lateralis during conditions. Data, presented as mean ( SD ), were compared using Bayesian RMANOVA, except for perceived effort and discomfort, which were compared using a Friedman's test (non‐parametric). Results 60% (Δcm before‐after‐0: TC = 0.04 [0.09], PM = −0.01 [0.15], BFR = 0.00 [0.11], PM + BFR = 0.01 [0.22]) and 70% (Δcm before‐after‐0: TC = 0.01 [0.09], PM = −0.01 [0.15], BFR = 0.02 [0.11], PM + BFR = −0.03 [0.22]) muscle thickness did not change. Perceived effort was greater than TC following PM ( p  = .05) and PM + BFR ( p  = .001). Perceived discomfort was greater following BFR and PM + BFR compared to TC (all p  ≤ .002) and PM (all p  ≤ .010). Changes in deoxygenation (e.g. channel 1; ΔμM start set 1‐end set 3: TC = 0.9 [1.2], PM = −1.2 [1.9], BFR = 10.3 [2.7], PM + BFR = 10.3 [3.0]) were generally greater with BFR and PM + BFR (BF inclusion  = 1.210e + 13). Conclusion Acute muscular responses to PM + BFR are not augmented over the effect of BFR alone.