ECSS Paris 2023: OP-AP37
INTRODUCTION: Athletes often incorporate resistance training (RT) to enhance strength and performance, however during certain training phases, RT is de-loaded (DLRT), possibly limiting its effectiveness. Blood flow restricted RT (BFRRT) can elicit muscular adaptations similar to heavy load RT (HLRT), while only requiring low loads, making it a potential solution during de-loading periods. However, differences between these RT strategies in the acute physiological responses and any subsequent fatigue remains unclear. Therefore, this study aimed to compare the physiological, perceptual, and performance effects of BFRRT, HLRT, and DLRT acutely and for 48-h post-training. METHODS: Eighteen resistance-trained females completed half squat (1RM = 96.2 ± 18.0 kg) and split squat (1RM = 72.4 ± 14.6 kg) under 3 exercise conditions: 1) BFRRT (half squat = 1 set: 30 repetitions, 3 sets: 15 repetitions; split squat = 4 sets: 15 repetitions on each leg; 30%1RM, 30 s inter-set rest, 60% arterial occlusion pressure), 2) HLRT (5 sets: 5 repetitions, 80%1RM, 3 min inter-set rest), 3) DLRT (3 sets: 3 repetitions, 75%1RM, 45 s inter-set rest). Follow-up testing was conducted 24- and 48-h after each condition. Blood lactate was recorded pre- and 2 min post-exercise. Session rating of perceived exertion (sRPE) was recorded 20 min post-session. Maximal voluntary contraction (MVC), countermovement jump (CMJ) height, and muscle soreness were measured before and after experimental sessions, and at all follow-up sessions. Data were log10 transformed and analysed using a linear mixed model with Bonferroni post-hoc comparisons. RESULTS: Blood lactate increased post-exercise for all conditions, with BFRRT (+90.0%, dz = 2.2) and HLRT (+71.4%, dz = 1.7) significantly higher than DLRT, and BFRRT also higher than HLRT (+22.1%, dz = 0.6). sRPE was significantly higher in BFRRT (+54.6%, dz = 1.6) and HLRT (+41.7%, dz = 1.2) compared to DLRT; but were not different from each other. MVC significantly decreased from pre- to post-exercise (-11.8%, dz = 0.6), but with no between-condition differences. Muscle soreness in BFRRT (+84.1%, dz = 1.2) and HLRT (+93.2%, dz = 1.5) were significantly higher than DLRT at all time points. Within-condition analysis showed increased soreness 48-h post-exercise in BFRRT (+80.9%, dz = 0.7) and HLRT (+137.85%, dz = 1.3) compared to pre-exercise. Muscle soreness at 48-h post-exercise was significantly lower in BFRRT than HLRT (-63.9%, dz = -0.6); however, BFRRT was higher than DLRT (+88.2%, dz = 0.6). There were no significant effects for time or condition for CMJ. CONCLUSION: BFRRT elicits similar acute physiological and perceptual responses to HLRT, with reduced post-exercise muscle soreness and no difference in performance during the recovery period. Therefore, BFRRT may be a viable alternative to HLRT when muscle soreness is contraindicated, but the long-term efficacy of this approach requires further investigation.
Read CV Kristen De MarcoECSS Paris 2023: OP-AP37
INTRODUCTION: Canoeing requires coordination, core stability, and strength, engaging both aerobic and anaerobic energy systems [1]. While upper extremity strength is often emphasized, lower extremity strength is equally important for optimal performance. Strength training enhances both performance and endurance, with resistance exercises at ≥65% one-repetition maximum (1 RM) promoting muscle hypertrophy [2, 3]. Blood Flow Restriction (BFR) training provides a low-intensity (20-30% 1 RM) alternative, simulating the effects of high-intensity exercise through hypoxia [4]. Research shows that BFR training improves muscle size, strength, and psychological motivation [5], a key factor in athletic success [6]. This study investigates the effects of BFR training on lower extremity strength, muscle thickness, and sportive motivation in elite male canoe athletes. METHODS: Seventeen male national team canoe athletes (aged 18-25) participated in this study. Muscle thickness and cross-sectional area (CSA) of lower extremity muscles were measured using ultrasound, while isokinetic strength was assessed at 60˚/s with a Biodex System. Motivation was evaluated using the Sport-Specific Achievement Motivation Scale (SSAMS). The 8-week BFR training program utilized KAATSU C3 cuffs at 30% of 1 RM for Quadriceps, Hamstrings, and Leg Press exercises, with progressive pressure increases. Training sessions included warm-up, three to four sets of exercises, and cool-down. Measurements were taken pre- and post-training to assess outcomes. RESULTS: The participants included in the study had an average age of 18.59 ± 0.71 years, an average sports age of 6.88 ± 1.17 years, an average weekly training frequency of 7.24 ± 1.64 days, an average height of 177.28 ± 7.27 cm, and an average body weight of 74.74 ± 11.19 kg. Muscle measurements showed notable bilateral increases, including Rectus Femoris Thickness (RFT) rising from 1.74 ± 0.24 cm to 1.91 ± 0.22 cm (p<0.001) on the right and from 1.56 ± 0.26 cm to 1.79 ± 0.29 cm (p<0.001) on the left. Cross-sectional area (CSA) of the Rectus Femoris (RF) and Hamstrings also significantly increased. Isokinetic strength tests demonstrated enhanced Quadriceps Femoris (QF) peak torque (PT), with right QF PT increasing from 198.16 ± 36.58 Nm to 227.12 ± 46.91 Nm (p=0.002) and left QF PT from 191.52 ± 27.33 Nm to 224.45 ± 42.51 Nm (p=0.001). Motivation scores also improved, particularly in the “Motivation to Approach Success” and “Avoiding Failure” subscales (p<0.001). CONCLUSION: BFR training effectively enhances muscle performance and psychological factors in elite athletes [1]. The findings highlight the unique benefits of BFR training, which enhances hypertrophy through hypoxic conditions and recruits fast-twitch muscle fibers without requiring high-intensity loading, significantly reducing the risk of injury [2]. REFERENCES 1- Paquette et al., 2018 2- McArdle et al., 2010 3- Riebe et al., 2018 4- Pignanelli et al., 2021 5- Wortman et al., 2021 6- Abe et al., 2006
Read CV burcin ugur tosunECSS Paris 2023: OP-AP37
INTRODUCTION: Low-load Blood Flow Restriction training (BFR) is a viable alternative to high-load resistance training (HL), due to its lower mechanical tension, where still comparable or slightly lower gains in muscle hypertrophy and strength are seen (1). However, neural adaptations remain poorly understood and are hypothesized to be less pronounced, while sex differences have hardly been studied at all (2). Thus, this study aimed to investigate the sequential application of HL following BFR on neuromuscular and hypertrophic adaptation and compare its sex-dependent effects (3). METHODS: In this 10-week randomized controlled trial, 37 healthy male and female adults (35-60 years) completed progressive resistance training for knee extensors either 8 weeks with low-load BFR followed by 2 weeks of HL, or exclusively HL training. Measurements at baseline including familiarization (PRE1 and PRE2), 8 weeks (MID) and 10 weeks (POST) included maximal voluntary contraction of knee extensors (MVC), voluntary activation (VA, via electrical muscle stimulation) and vastus lateralis and rectus femoris muscle volume (VL_RF, via ultrasound at 30-70% femur length). Linear mixed models were used to analyze group differences over time and between sex, reporting Cohen’s d effect sizes. RESULTS: The HL group showed greater increase in MVC at MID and POST (d=0.49*[-0.01;0.99]) compared to the BFR group, with females benefiting slightly more at MID (d=0.15[-0.47; 0.78) but not at POST (d=-0.15[-0.78;0.47]). VA changes at MID and POST were slightly negative for HL (d=-0.25[-1.54; 1.03]), however, females demonstrated larger improvements at MID (d=0.62[-0.97;2.22]) and POST (d=0.77[-0.83; 2.36]). While the BFR group showed greater improvements in VL_RF at MID (d=0.25[-0.29; 0.80]), HL was more beneficial for females (d=0.48[-0.24; 1.20]). CONCLUSION: Our findings suggest that HL is more effective for neuromuscular adaptations, whereas BFR may offer short-term hypertrophic benefits. However, as the differences were small on a group level and large variability was present, it seems that not just mechanical tension, but also metabolic stress is a driver of neuromuscular adaption (3). Notably, HL was particularly beneficial for females, leading to greater increases in muscle size and neuromuscular function. Future research should further deepen sex-specific responses to optimize resistance training protocols.
Read CV Romina LedergerberECSS Paris 2023: OP-AP37