BLOOD FLOW-RESTRICTION INFLUENCES VERY FEW VARIABLES
De Oliveira, F. B., Lima, L. C., Oliveira, T. P., Santos, F. A., Assumpcao, C. O., Greco, C. C., & Denadai, B. S. (2014). Blood-flow restriction walking training influences running economy? Medicine & Science in Sports & Exercise, 46(5), Supplement abstract number 1202.
This study analyzed the effect of blood-flow restriction on running economy untrained young men (N = 18). Ss were randomly divided into two groups: i) blood-flow restriction, and ii) walking training without blood-flow restriction. Both groups underwent the same testing pre- and post-training: i) treadmill incremental test to obtain the maximal oxygen uptake (VO2max); ii) rectangular treadmill test at 8 km/h to measure running economy; iii) two maximum isometric contractions of the knee extensors and knee flexors to measure maximum voluntary contraction, maximum rate of force development, and semitendinosus, biceps femorus, rectus femorus, and vastus lateralis EMG activity; iv) estimation of plantar flexors muscle-tendon stiffness; and v) measurement of the thigh muscle-bone cross sectional area using ultrasound imaging. Twenty-eight training sessions (7 days per week) of 20-minutes of continuous walking were performed. The blood-flow restriction group trained with both legs restricted at a pressure equivalent to 80% of resting systolic blood pressure (~100 mmHg). The walking speed was progressively increased during the four weeks (from 4.0 to 5.0 km/h).
The thigh muscle-bone cross sectional area of the blood-flow restriction group increased significantly (4.4%). No significant changes were found for any other variables in the blood-flow restriction group. No significant changes in any variable occurred in the walking without blood-flow restriction group.
Implication. Blood-flow restriction improved muscle hypertrophy without significant modification of running economy or aerobic capacity in untrained young men.