Research Review: Blood Flow Restriction Allows for Strength Training in Older Adults without Requiring High Loads

Centner C, et al. (2019) Effects of blood flow restriction training on muscular strength and hypertrophy in older individuals: A systematic review and meta-analysis. Sports Med;49:95-108.

Introduction

Applying tourniquets or inflatable cuffs at the proximal portion of a limb–referred to as blood-flow restriction (BFR)– during low-load (LL) [20-to-30% of one repetition maximum (1RM) resistance training (RT)] has been shown to promote muscular hypertrophy and strength increases comparable to what achieved following typical high-load (HL) resistance training [70–85% 1RM.]

The advantage of using low-loads is reduced mechanical stress on joints and bones and thus is of particular interest for populations who are not capable of, or should not lift near-maximum loads. This includes individuals in clinical rehabilitation, those with heart disease and most older individuals with decreased tolerances to mechanical stress.

Purpose

The purpose of this study was to perform a systematic review and statistical analysis using the meta-analysis technique (a method for systematically combining pertinent qualitative and quantitative study-data from several selected studies to develop a single conclusion with sufficient statistical power) to assess the effects of LL-BFR-RT on muscle strength and muscle mass in older subjects, and to compare LL-BFR-RT to HL-RT strength outcomes.

Methodology

              A review of the world literature on LL-BFR-RT and HL-RT was performed. A total of 2658 studies were identified, but only 11 met the inclusion criteria that included studies published in English using healthy older people (aged > 50 years) and that made comparisons between low-load and high-load resistance training with and without blood-flow restriction [HL (> 70% 1RM) or LL (< 50% 1RM) resistance training], or between walking with and without simultaneous BFR, on muscle mass and/or strength gains, pre- and post-training.

Results

1. HL and LL-BFR training produce similar increases in muscle mass in older adults compared with common HL-RT.
2. Adaptations in muscular strength were smaller following LL-BFR training compared with those typically seen following HL training.
3. Application of an external tourniquet seems to facilitate significantly greater responses in muscular strength compared with LL training alone.
4. Due to the limited number of studies, no definitive conclusions can be drawn about the effects of LL-BFR training on muscle mass compared with LL training alone. However, these data are highly suggestive of positive effects of using BFR to enhance strength and muscle mass.
5. The data suggest that low intensity walking with BFR enhances strength and muscle mass adaptations in older subjects compared with only normal walking.

Key Findings

1. Blood-flow restriction (BFR) can be an effective strategy for increasing – effects of low-load resistance training and walking on muscle mass and strength in older adults.
2. Low-load, blood flow restriction resistance training produces comparable changes in muscle mass but lower increases in muscular strength.
3. Adding blood-flow restriction to low-load resistance training or walking represents an effective exercise alternative for older populations where high-load resistance training is contraindicated.

Conclusions

Application of blood-flow restriction to low-load resistance training and walking exercise positively influences muscular adaptations compared with each exercise under normal blood-flow conditions. In comparison with high-load resistance training, low-load resistance training elicits lower strength increases.