Supervisors info:
Αναστάσιος Φιλίππου, Αναπληρωτής Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Χρυσανθόπουλος Κωνσταντίνος, Ε.Ε.Π., Ιατρική Σχολή, ΕΚΠΑ
Καρατζάνος Ελευθέριος, Ε.Ε.Π., Ιατρική Σχολή, ΕΚΠΑ
Summary:
INTRODUCTION
Blood flow restriction (BFR) has gained the interest of the scientific community over the last several decades. Numerous studies continue to be conducted in order to examine the benefits of BFR in strength, muscle hypertrophy, as well as the chronic and acute effects of this type of training on aerobic and anaerobic capacity. Research has been carried out on sportsmen, athletes, clinical populations, women, and men, using either a cycle ergometer, walking on a treadmill, or with field tests. However, there has been no corresponding treadmill running studies to record the direct effects of a protocol of increasing exercise intensity until exhaustion. Furthermore, the acute effect of BFR on maximal oxygen consumption (VO2max) has not been studied. The purpose of this study was to examine the influence of BFR application during an incremental maximal running protocol in order to investigate the effect of BFR application and to provide evidence regarding the body's acute responses to exercise of increasing intensity to fatigue with and without blood flow restriction.
MATERIAL AND METHOD
Fifteen male club level runners (35.7 ± 10,1 yrs, Height 176.3 ± 5.7 cm, body mass 73.6 ± 5,00 kg, mean ± SD) performed an incremental running protocol (speed increment 1 km/h per 90 s, inclination 0%) to volitional fatigue two times over the course of 7-15 days. One test was performed with blood flow restriction (BFR) and the other without BFR (C), in random order. The occlusion level of BFR was at 40% of maximum Arterial Occlusion Pressure (A.O.P) and cuffs were placed on the upper first third of the thigh. Diet and training the day before and on the day of the measurements were controlled.
RESULTS
No difference was observed in V̇O2max in ml/kg/min (BFR: 49,7± 4,9 ml/kg/min Vs C: 51,41±5,2 ml/kg/min p= 0.098) and in l/min (BFR: 3,65± 0,37 l/min Vs C: 3,76± 0,37 l/min p=0,21) between the two conditions. On the contrary, exercise time (BFR: 476.7 ± 83.3 Vs. C: 606.1 ± 80s, p=0.001) and speed at V̇O2max (BFR: 16.7 ± 1.4 km/h Vs. C: 17.99 ± 1.68 km/h, p<0.001) were lower with occlusion. Oxygen uptake as recorded at four submaximal speeds between 12-15 km/h yielding running economy was not different (p > 0.05). The velocity at the anaerobic threshold (BFR: 13.3 ± 1.3 Vs. C: 14.0 ± 1.8 km/h) was higher in the control condition (p =0.01). Also, perceived rate of exertion (BFR: 17.3 ± 1.2 Vs. C: 16.2 ± 1.7) and pain perception on a 10-point pain scale (BFR: 7.8 ± 1.2 Vs. C: 5.5 ± 2.1 (p < 0.05) were lower in the control. Finally, maximal heart rate (BFR: 185 ± 9 Vs. C: 187 ± 11 b/min) (p > 0.05) was not different between the two conditions.
CONCLUSION
The application of BFR at 40% of maximum Arterial Occlusion Pressure (A.O.P) during an incremental running protocol reduces exercise time and speed at V̇O2max but does not affect V̇O2max values in male club level runners.
Keywords:
Blood flow restriction, BFR, Aerobic capacity, VO2max, Occlusion
