Abstract
The purpose of this study was to compare the effects of different combinations of blood flow restriction (BFR) pressure and exercise intensity on aerobic, anaerobic, and muscle strength adaptations in physically active collegiate women. Thirty-two women (age 22.8 ± 2.9 years; body mass index 22.3 ± 2.7 kg/m2) were randomly assigned into four experimental training groups: (a) increasing BFR pressure with constant exercise intensity (IP-CE), (b) constant partial BFR pressure with increasing exercise intensity (CPp-IE), (c) constant complete BFR pressure with increasing exercise intensity (CPC-IE), and (d) increasing BFR pressure with increasing exercise intensity (IP-IE). The participants completed 12 training sessions comprised of repeated bouts of 2 min running on a treadmill with BFR interspersed by 1-min recovery without BFR. Participants completed a series of tests to assess muscle strength, aerobic, and anaerobic performances. Muscle strength, anaerobic power, and aerobic parameters including maximum oxygen consumption (VO2max), time to fatigue (TTF), velocity at VO2max (vVO2max), and running economy (RE) improved in all groups (p ≤ 0.01). The CPC-IE group outscored the other groups in muscle strength, RE, and TTF (p < 0.05). In summary, participants with complete occlusion experienced the greatest improvements in muscle strength, aerobic, and anaerobic parameters possibly due to increased oxygen deficiency and higher metabolic stress.
Highlights
Endurance training improves performance capacity via targeted muscular and cardiovascular adaptations such as an increase in oxidative enzymes, capillary density, glycogen content, and increases in stroke volume and cardiac hypertrophy (Nadel, 1985)
The percentage change was different between groups (IP-CE: 9.6 ± 2.0%; CPP-IE: 11.2 ± 5.5%; complete BFR pressure with increasing exercise intensity (CPC-IE): 14.8 ± 4.9%; increasing BFR pressure with increasing exercise intensity (IP-IE): 8.4 ± 2.4%)
Bonferroni post hoc tests revealed a significant difference between the CPC-IE group with increasing BFR pressure with constant exercise intensity (IP-CE) (p = 0.04) and IP-IE (p = 0.04) groups
Summary
Endurance training improves performance capacity via targeted muscular and cardiovascular adaptations such as an increase in oxidative enzymes, capillary density, glycogen content, and increases in stroke volume and cardiac hypertrophy (Nadel, 1985). Former research suggests that training adaptations maybe further enhanced by the addition of ischemia to working muscles (Sundberg, 1994). Sundberg (1994) applied 50 mmHg restrictive pressure on one leg during exercise for 4 weeks while the contralateral leg was trained without occlusion, and the results indicated a greater peak oxygen uptake and TTF in the ischemic condition. In BFR conditions, active muscles encounter a ischemia state which imposes a greater metabolic stress on working muscles (Tanimoto et al, 2005). The additional metabolic stress of BFR and especially venous occlusion increases muscle cell swelling (Loenneke et al, 2012), activates intra-cellular anabolic pathways (Abe et al, 2005), and recruits fast-twitch fibers (Yasuda et al, 2009), which are thought to be involved in muscular adaptation. The adaptations to exercise with BFR depend on several factors including the pressure of occlusion (i.e., partial or complete), the type of occlusion (i.e., continuous or intermittent), the intensity of exercise (i.e., low, moderate, or high), and the volume of exercise with BFR
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have