Author(s): LATOCHA, A., GREN, A., GEPFERT, M., Institution: AKADEMIA WYCHOWANIA FIZYCZNEGO IM. JERZEGO KUKUCZKI W KATOWICACH, Country: POLAND, Abstract-ID: 2192

INTRODUCTION:
The utilization of blood flow restriction (BFR) during low-load resistance training has proven to be an effective method for inducing muscle hypertrophy comparable to high-load resistance training. The mechanisms underlying the effectiveness of BFR are not fully understood, but available evidence suggests that it contributes to increased endocrine responses, while also eliciting low levels of exercise-induced muscle damage and local fatigue. Therefore, this study aimed to compare acute effects of low-load with and without BFR and high-load resistance training on epinephrine level and jumping performance.
METHODS:
The study included 23 healthy and physically active participants (age: 24±3years; body mass: 70.8±11.6kg; body height:174.1±8.9cm; one-repetition maximum [1RM] leg press: 289±70kg). After familiarization session and 1RM leg press assessment participants were randomly assigned to one of the leg press workout under following conditions: i) low-load (30% 1RM 30/15/15/15); ii) high-load (70%1RM 10/10/10/10); iii) BFR (30%1RM 30/15/15/15 at 80% arterial occlusion pressure). In the experimental session, blood was initially collected (pre-workout), and then the participants performed an individual warm-up, after which they began to perform baseline measurements of countermovement jumps (CMJ; pre-workout). To induce BFR, inflatable cuffs were applied on most proximal part of both lower limbs with individually adjusted arterial occlusion pressure of 80%. Immediately after the workout post-test has been performed (post-workout).
RESULTS:
The two-way repeated measures ANOVA didn’t show a significant interaction on AD level (p=0.591), nor a main effect of group (p=0.954) but it did show significant main effect of the time (p<0.05; p=0.020), indicating an increase in AD level from pre- to post-workout (11.5±8.89 vs 22.4±22.6µg). There was also no significant interaction for jump height (p=0.853), nor main effect of group (p=0.011), but there was a significant main effect of time (p<0.05; p=0.020), to decrease jump height from pre- to post-workout (37.2±10.8 vs 34.8±11.3cm). Additionally, the two-way repeated measures ANOVA didn’t show a significant interaction (p=0.979), nor main effect of group (p=0.014), and time (p=0.064) for relative peak power.
CONCLUSION:
This study showed that both low-load resistance training with and without BFR, as well as high-load resistance training, led to a significant acute increase in adrenaline levels and fatigue assessed by CMJ performance. Surprisingly, the results of this study suggest that neither BFR nor the load used during resistance training significantly moderated changes in adrenaline levels. Consequently, even low-load lower-limb resistance workout resulted in a significant increase in adrenaline levels and a concomitant decrease in subsequent jump performance. Future long-term studies involving larger samples are necessary to confirm these findings.