Introduction: The purpose of this study was to clarify whether blood-flow restriction during resting intervals [resting blood-flow restriction (rBFR)] is comparable to a continuous BFR (cBFR) training regarding its effects on maximum strength, hypertrophy, fatigue resistance, and perceived discomfort.Materials and Methods: Nineteen recreationally trained participants performed four sets (30-15-15-15 repetitions) with 20% 1RM on a 45° leg press twice a week for 6 weeks (cBFR, n = 10; rBFR, n = 9). Maximum strength, fatigue resistance, muscle thickness, and girth were assessed at three timepoints (pre, mid, and post). Subjective pain and perceived exertion were determined immediately after training at two timepoints (mid and post).Results: Maximum strength (p < 0.001), fatigue resistance (p < 0.001), muscle thickness (p < 0.001), and girth (p = 0.008) increased in both groups over time with no differences between groups (p > 0.05). During the intervention, the rBFR group exposed significantly lower perceived pain and exertion values compared to cBFR (p < 0.05).Discussion: Resting blood-flow restriction training led to similar gains in strength, fatigue resistance, and muscle hypertrophy as cBFR training while provoking less discomfort and perceived exertion in participants. In summary, rBFR training could provide a meaningful alternative to cBFR as this study showed similar functional and structural changes as well as less discomfort.

The deep fascia is intimately linked to skeletal muscle and may be involved in delayed onset muscle soreness (DOMS). The present study therefore explored the effect of eccentric exercise on fascia stiffness and its relation with DOMS. Healthy active male adults (n = 19, 27 ± 4 years) performed 6 x 10 maximal eccentric knee flexions using an isokinetic dynamometer. Before (baseline) as well as immediately (T0), 1 hour (T1), and each day up to 72 hours (T24 to T72) afterwards, shear wave elastography was used to measure the mechanical stiffness of the biceps femoris muscle and the overlying fascia. As a surrogate of DOMS, pain upon palpation was captured by means of a 100mm visual analogue scale. While muscle stiffness remained unchanged (p > 0.05), deep fascia stiffness increased from baseline to T24 (median: 18 kPa to 21.12 kPa, p = 0.017) and T72 (median: 18 kPa to 21.3 kPa, p = 0.001) post-exercise. Linear regression showed an association of stiffness changes at T24 and pressure pain at T72 (r2 = 0.22, p < 0.05). Maximal eccentric exercise leads to a stiffening of the fascia, which, in turn, is related to the magnitude of future DOMS. Upcoming research should therefore gauge the effectiveness of interventions modifying the mechanical properties of the connective tissue in order to accelerate recovery.

This study investigated the effects of a relatively high‐ versus moderate‐volume resistance training program on changes in lean mass during caloric restriction. Thirty‐eight resistance‐trained males were randomized to perform either a high‐volume (HVG; 5 sets/exercise) or a moderate‐volume (MVG; 3 sets/exercise) resistance training program. Both groups were supervised during lower body training. Participants consumed 30 kcal/kg for 6 weeks after 1 week of weight maintenance (45 kcal/kg), with protein intake fixed at 2.8 g/kg fat‐free mass. Muscle thickness of the m. rectus femoris, body composition, contractile properties, stiffness, mood, and sleep status were assessed at pre‐, mid‐, and post‐study. No significant group × time interaction was observed for muscle thickness of the m. rectus femoris at 50% (∆ [post‐pre] 0.36 ± 0.93 mm vs. ∆ −0.01 ± 1.59 mm; p = 0.226) and 75% length (∆ −0.32 ± 1.12 mm vs. ∆ 0.08 ± 1.14 mm; p = 0.151), contractility, sleep, and mood in the HVG and MVG, respectively. Body mass (HVG: ∆ −1.69 ± 1.12 kg vs. MVG: ∆ −1.76 ± 1.76 kg) and lean mass (∆ −0.51 ± 2.30 kg vs. ∆ −0.92 ± 1.59 kg) decreased significantly in both groups (p = 0.022), with no between‐group difference detected (p = 0.966). High‐volume resistance training appears to have neither an advantage nor disadvantage over moderate‐volume resistance training in terms of maintaining lean mass or muscle thickness. Given that both groups increased volume load and maintained muscle contractility, sleep quality, and mood, either moderate or higher training volumes conceivably can be employed by resistance‐trained individuals to preserve muscle during periods of moderate caloric restriction.