Postactivation Performance Enhancement With Low-Load Upper-Body Exercise Using Blood Flow Restriction or Electrical Muscle Stimulation in Volleyball

ABSTRACT: Akçay, N, Kamiş, O, Keskin, K, Özmen, T, Sofuoğlu, C, Süpürgeci, N, Rolnick, N, and Montoye, A. Post-activation performance enhancement with low-load upper-body exercise using blood-flow restriction or electrical muscle stimulation in volleyball. J Strength Cond Res XX(X): 000-000, 2026-This study aimed to compare the acute effects of low-load resistance exercise (LL-RE) performed alone, with blood flow restriction (BFR), or with electrical muscle stimulation (EMS) on handgrip strength and serve speed during single- and multijoint upper-body exercises in well-trained male volleyball players. Fifteen collegiate volleyball players (age: 20.9 ± 2.8 years, height: 180.1 ± 6.4 cm; body mass: 83 ± 5.7 kg) completed 6 randomized sessions at 72-hour intervals. Bench press and triceps push-down were performed 30% of 1RM for 4 sets (30, 15, 15, and 15 repetitions), with 30 seconds of rest between sets in 3 conditions: LL-RE alone, LL-RE + BFR (50% arterial occlusion pressure), and LL-RE + EMS (75 Hz). Only one exercise was performed per experimental session; therefore, 3 sessions involved the bench press and 3 sessions involved the triceps push-down. Handgrip strength and serve speed were assessed 5 minutes postexercise. After bench press, handgrip strength was significantly greater after LL-RE with BFR (Δ = +3.7 kg, p = 0.043, d = 0.77) and LL-RE + EMS (Δ = +3.4 kg, p = 0.036, d = 0.79) compared with baseline, with no differences compared with LL-RE alone. After the triceps push-down, LL-RE combined with EMS elicited significantly greater improvements in handgrip strength than LL-RE alone (Δ = +2.1 kg, p = 0.029, d = 0.86), while all 3 conditions showed significant increases compared with baseline (LL-RE alone: +4.4 kg, p = 0.010; BFR: +5.9 kg, p = 0.002; EMS: +6.5 kg, p < 0.001, d = 1.02-1.39). Serve speed did not differ significantly across conditions (p > 0.05). These findings demonstrate that LL-RE combined with BFR or EMS can modestly enhance acute handgrip strength, particularly during single-joint exercise; however, volleyball serve speed did not differ across all 6 experimental conditions. For coaches and athletes, incorporating LL-RE with BFR or EMS as part of a warm-up routine may provide small but meaningful acute improvements in upper-body strength performance.