AUTHOR=Cook Summer B. , Cleary Christopher J. 

TITLE=Progression of Blood Flow Restricted Resistance Training in Older Adults at Risk of Mobility Limitations

JOURNAL=Frontiers in Physiology

VOLUME=Volume 10 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2019.00738

DOI=10.3389/fphys.2019.00738

ISSN=1664-042X

ABSTRACT=Blood flow restriction (BFR) resistance training leads to increased muscle mass and strength but the progression leading to adaptations may be different as strength gains are often to a lesser magnitude than high-load (HL) training. The impact of training loads and repetitions on older adults’ muscle mass and strength following BFR or HL training was evaluated. Twenty-one older adults (67-90 years) classified as being at risk of mobility limitations were randomly assigned to HL (n=11) or BFR (n=10) knee extension (KE) and flexion (KF) training twice per week for 12 weeks. Strength was measured with 10-repetition maximum (10-RM) tests and isometric contractions. Cross-sectional area (CSA) of the quadriceps and hamstrings was measured. HL and BFR interventions increased 10-RM KF and isometric strength (P<.05) and hamstrings CSA increased an average of 4.8+5.9% after HL and BFR training (time main effect P<.01). There were no differences between the training groups (time x group interactions P>.05). The rate of progression of KF training load and repetitions was comparable (time x group interactions of each variable P>.05). The groups averaged an increase of .50+.25 kg∙week-1 and 1.8+.1.7 repetitions∙week1 of training (time main effects P<.05). The HL training group experienced greater improvements in KE 1-RM strength than the BFR group (60.7+36.0% vs 35.3+25.5%; P=.03). In both groups, isometric KE strength increased 17.3+18.5% (P=.001) and there were no differences between groups (P=.24). Quadriceps CSA increased (time main effect P<.01) and to similar magnitudes (time x group interaction P=.62) following HL (6.5+3.1%) and BFR training (7.8+8.2%). The HL group experienced accelerated progression of load when compared to BFR (.90+.60 kg∙week-1 vs .30+.21 kg∙week-1; P=.006) but was not different when expressed in relative terms. BFR training progressed at a rate of 2.2+.43 repetitions∙week-1 while the HL group progressed at 3.6+1.3 repetitions∙week-1 (P=.003). HL training led to greater increases in KE 10-RM and it may be attributed to the greater load and/or faster rate of progression of the load throughout the 12-week training period and the specificity of the testing modality. Incorporating systematic load progression throughout BFR training periods should be employed to lead to maximal strength gains.