Neuromuscular Adaptations after Blood Flow Restriction Training Combined with Nutritional Supplementation: A Preliminary Study

Abstract

Blood fl ow restriction training (BFRT) has been shown to be an eff ective alternative technique to conventional resistance training to increase skeletal muscle hypertrophy and strength. However, neuromuscular response to BFRT in combination with nutritional supplementation has rarely been studied. Th e purpose of this study was to investigate the eff ects of BFRT combined with creatine monohydrate (CrM) and/or hydroxymethyl butyrate (HMB) on skeletal muscle size and strength. Fift een healthy males were randomly divided into three groups: a) BFRT without supplementation (C-BFR); b) BFRT with CrM supplementation (0.3 g / kg -1 ) (CrM-BFR); and c) BFRT with CrM (0.3 g / kg -1 ) and HMB (3 g) supplementation (CrM + HMB-BFR). Participants performed elbow fl exion exercise (30% of maximal isometric voluntary contraction (MIVC)) at 30% of total occlusion pressure, twice a week, for three weeks. MIVC of the elbow fl exion and brachial biceps muscle thickness were assessed pre-and post-training. Th ere was no signifi cant group-by-time interaction for MIVC values (p>0.05). Biceps muscle thickness was signifi cantly increased from pre-to post-test in all groups (p<0.05). Th e C-BFR group obtained a greater value of eff ect size (d=2.2). Th ese fi ndings suggest that 3 weeks of CrM and HMB supplementation had no infl uence on BFRT-induced neuromuscular adaptations. KEY WORDS Skeletal muscle hypertrophy, muscle strength, occlusion training.

Is there rationale for the cuff pressures prescribed for blood flow restriction exercise? A systematic review

“…The populations examined were relatively heterogeneous between studies, with the most common population being healthy non‐resistance trained but recreationally active adults, examined in 23 of the 52 included studies 17,24,31‐51 . Other populations included resistance‐trained adults, adults with musculoskeletal or soft tissue injuries, older adults, or adults with hypertension.…”

“…Other populations included resistance‐trained adults, adults with musculoskeletal or soft tissue injuries, older adults, or adults with hypertension. There were far more studies (26 of 52) examining only male participants, 17,24,25,30,32‐38,41‐43,46,48,50‐59 compared with just 8 of 52 examining only female participants, 40,49,60‐65 leaving 18 studies examining both of these genders 8,19,20,39,44,45,47,66‐75 …”

“…The majority of the included studies were acute studies, with only 16 of the 52 included studies assessing adaptations to BFR exercise training 8,35,38,39,41,44,48,50,51,56,59,62,64‐66,74 . Most studies employed traditional upper or lower body resistance exercise protocols, commonly utilizing elbow flexion, leg press, or knee extension exercises.…”

“…Sixteen of the 52 included studies applied multiple different cuff pressures as a means of comparing acute responses or chronic adaptations to different applied pressures 17,20,31,32,36,39,43,44,48,54,67,68,70,72,73,75 . Among the remaining 36 studies using a single individualized pressure for their application of BFR, 13 studies used 80% AOP/LOP, 24,37,40,49,50,57,61,62,64‐66,71,74 7 studies used 60% AOP/LOP, 8,33,34,38,46,52,56 5 studies used 50% AOP/LOP, 25,41,42,59,60 4 studies used 100% AOP, 47,51,58,63 4 studies used 40% AOP/LOP, 19,30,45,69 and 3 studies used 30% AOP 35,53,55 . The technique and postures used to determine each of these individualized restriction pressures was similarly variable.…”

“…Upper limb restriction was generally measured using either the radial or brachial arteries, and lower body restriction measured in one of the tibial arteries, or the popliteal artery. The posture in which assessment of occlusion pressure was conducted was not reported in 15 of the 52 included studies 24,30,32,34,35,43,47,49,51,53,58,61‐63,74 . Among those reporting participant posture during assessment, supine 17,36,37,40,42,48,50,54,56,57,59,64,65 or standing 8,19,20,31,41,44,46,52,69,70,72,73,75 were each chosen in 13 studies, and sitting was used in 11 studies 25,33,38,39,45,55,60,66‐68,71 …”