Exercise intensity and muscle hypertrophy in blood flow-restricted limbs and non-restricted muscles: a brief review.
ABSTRACT Although evidence for high-intensity resistance training-induced muscle hypertrophy has accumulated over the last several decades, the basic concept of the training can be traced back to ancient Greece: Milo of Croton lifted a bull-calf daily until it was fully grown, which would be known today as progressive overload. Now, in the 21st century, different types of training are being tested and studied, such as low-intensity exercise combined with arterial as well as venous blood flow restriction (BFR) to/from the working muscles. Because BFR training requires the use of a cuff that is placed at the proximal ends of the arms and/or legs, the BFR is only applicable to limb muscles. Consequently, most previous BFR training studies have focused on the physiological adaptations of BFR limb muscles. Muscle adaptations in non-BFR muscles of the hip and trunk are lesser known. Recent studies that have reported both limb and trunk muscle adaptations following BFR exercise training suggest that low-intensity (20-30% of 1RM) resistance training combined with BFR elicits muscle hypertrophy in both BFR limb and non-BFR muscles. However, the combination of leg muscle BFR with walk training elicits muscle hypertrophy only in the BFR leg muscles. In contrast to resistance exercise with BFR, the exercise intensity may be too low during BFR walk training to cause muscle hypertrophy in the non-BFR gluteus maximus and other trunk muscles. Other mechanisms including hypoxia, local and systemic growth factors and muscle cell swelling may also potentially affect the hypertrophic response of non-BFR muscles to BFR resistance exercise.
- SourceAvailable from: Pedro J Marín[Show abstract] [Hide abstract]
ABSTRACT: This study aimed to gain an insight into the adaptations of muscle strength and skeletal muscle thickness after two different volumes of blood flow restriction training (BFRT), and compare them with high-intensity training. The sample was divided into four groups: low-volume, low-intensity BFRT (BFRT LV); high-volume, low-intensity BFRT (BFRT HV); traditional high-intensity resistance training (HIT); and a control group, which maintained their routine activities (CON). Leg extension one repetition maximum (1RM), isokinetic peak knee extension, and flexion torques at 60°/s and 180°/s as well as muscle thickness of the rectus femoris (RF) and vastus lateralis (VL) were assessed at baseline and after 5 weeks of training BFRT LV (7.03%, P < 0.05), BFRT HV (6.24%, P < 0.05) and HIT (18.86%, P < 0.001) groups increased 1RM performance, while no changes were observed in the CON group. Muscle thickness of the RF and VL was increased irrespective of the training group (7.5%, P < 0.001; and 9.9%, P < 0.001, respectively). We conclude that doubling the exercise volume with BFRT causes no further benefit with muscular size or strength. Although similar increases in muscle thickness were observed between training groups, HIT increased 1RM performance to a greater extent compared to either volume of BFRT.Scandinavian Journal of Medicine and Science in Sports 12/2012; · 3.21 Impact Factor
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ABSTRACT: Vascular blood flow restriction (vBFR) training stimulates muscle hypertrophy by increasing muscle activation and muscle swelling. Previous studies used expensive pneumatic cuffs, which may not be practical for regular use. PURPOSE:: To investigate the acute effects of low intensity practical BFR (LI-pBFR) on muscle activation, muscle swelling and damage. METHODS:: Twelve trained male participants completed a 30, 15, 15, 15 repetition scheme at 30% of their leg press 1-RM under control and LI-BFR conditions. Under the LI-BFR trial, knee wraps were applied to the thighs at a pressure which resulted in venous, not arterial, occlusion. In the control trial, wraps were applied with zero pressure. Ultrasound determined muscle thickness was recorded at baseline, 0 minutes post with wraps, 0, 5 and 10 minutes post without wraps. Muscle activation was recorded during warm ups and on the final set of 15 repetitions. Indices of muscle damage (soreness, power, and muscle swelling) were also recorded. RESULTS:: There was a condition by time effect for muscle thickness (p < 0.0001, ES = 0.5), in which muscle thickness increased in the LI-pBFR condition 0 minutes post with wraps and through 5 minutes post without wraps. No changes occurred in the control. There was a condition by time effect for muscle activation (p < .05, ES = 0.2). LI-pBFR had greater activation than the control. There were no condition by time effects on indices of muscle damage. DISCUSSION:: Our data indicates that practical BFR significantly increases muscle activation and muscle thickness without increasing indices of damage.The Journal of Strength and Conditioning Research 02/2013; · 1.80 Impact Factor
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ABSTRACT: Combining blood flow occlusion, Kaatsu, with a daily treadmill-walking program increases muscular strength in young, healthy men. Research using a similar training program in older adults is lacking. The present case study examined functional activity and body impairment responses to a daily walking program with Kaatsu in an older adult. The 67-year-old female participant walked at 0.85 m/s for five 2-min bouts with 1 min of rest between bouts, five times/week for 8 weeks with lower extremity Kaatsu cuffs inflated. Outcomes (Timed Up and Go, the Six Minute Walk Test, Ten Meter Walk Test, lower extremity strength measures) were collected at baseline, 2, 4, 6, and 8 weeks. Vitals were measured at the beginning and end of each walking session. Descriptives were calculated over time to determine the temporal effects of the Kaatsu-walk training program. All assessments, Timed Up and Go, Six Minute Walk Test, Ten Meter Walk Test, and lower extremity strength measures, increased 18.2% up to 46.8% from baseline to post-test. Data suggested that the 8-week Kaatsu-walk training program increases outcomes in an older adult.Physical & Occupational Therapy in Geriatrics 02/2013; 31(1).