Low-intensity endurance training performed with blood flow restriction (ET-BFR) can improve muscle strength, cross-sectional area (CSA) and cardiorespiratory capacity. Whether muscle strength and CSA as well as cardiorespiratory capacity (i.e.:V˙O2max) and underlying molecular processes regulating such respective muscle adaptations are comparable to resistance and endurance training is unknown.Purpose
To determine the respective chronic (i.e.: 8 weeks) functional, morphological and molecular responses of ET-BFR training compared to conventional, unrestricted resistance training (RT) and endurance training (ET).Methods
Thirty healthy young men were randomly assigned to one of three experimental groups: ET-BFR (n=10, 4 days/wk, 30 min cycling at 40% of V˙O2max), RT (n=10, 4 days/wk, 4 sets of 10 reps leg-press at 70% of 1-RM with 60 s rest) or ET (n=10, 4 days/wk, 30 min cycling at 70% of V˙O2max) for 8 weeks. Measures of quadriceps CSA, leg press 1-RM, and V˙O2max as well as muscle biopsies were obtained prior to and post intervention.Results
Both RT and ET-BFR increased muscle strength and hypertrophy responses. ET-BFR also increased V˙O2max, total COXIV abundance and VEGF mRNA abundance despite the lower work load compared to ET.Conclusion
Eight weeks of ET-BFR can increase muscle strength and induce similar muscle hypertrophy responses to RT while V˙O2max responses also increased post-intervention even with a significantly lower work load compared to ET. Our findings provide new insight to some of the molecular mechanisms mediating adaptation responses with ET-BFR and the potential for this training protocol to improve muscle and cardiorespiratory capacity.