One-legged endurance training: leg blood flow and oxygen extraction during cycling exercise

TY - JOUR

T1 - One-legged endurance training: leg blood flow and oxygen extraction during cycling exercise

AU - Rud, B

AU - Foss, O

AU - Krustrup, Peter

AU - Secher, Niels H.

AU - Hallén, J

N1 - CURIS 2012 5200 012

PY - 2012/5

Y1 - 2012/5

N2 - Aim: As a consequence of enhanced local vascular conductance, perfusion of muscles increases with exercise intensity to suffice the oxygen demand. However, when maximal oxygen uptake (VO 2max) and cardiac output are approached, the increase in conductance is blunted. Endurance training increases muscle metabolic capacity, but to what extent that affects the regulation of muscle vascular conductance during exercise is unknown. Methods: Seven weeks of one-legged endurance training was carried out by twelve subjects. Pulmonary VO 2 during cycling and one-legged cycling was tested before and after training, while VO 2 of the trained leg (TL) and control leg (CL) during cycling was determined after training. Results:VO 2max for cycling was unaffected by training, although one-legged VO 2max became 6.7 (2.3)% (mean±SE) larger with TL than with CL. Also TL citrate synthase activity was higher [30 (12)%; P<0.05]. With the two legs working at precisely the same power during cycling at high intensity (n=8), leg oxygen uptake was 21 (8)% larger for TL than for CL (P<0.05) with oxygen extraction being 3.5 (1.1)% higher (P<0.05) and leg blood flow tended to be higher by 16.0 (7.0)% (P=0.06). Conclusion: That enhanced VO 2max for the trained leg had no implication for cycling VO 2max supports that there is a central limitation to VO 2max during whole-body exercise. However, the metabolic balance between the legs was changed during high-intensity exercise as oxygen delivery and oxygen extraction were higher in the trained leg, suggesting that endurance training ameliorates blunting of leg blood flow and oxygen uptake during whole-body exercise.

AB - Aim: As a consequence of enhanced local vascular conductance, perfusion of muscles increases with exercise intensity to suffice the oxygen demand. However, when maximal oxygen uptake (VO 2max) and cardiac output are approached, the increase in conductance is blunted. Endurance training increases muscle metabolic capacity, but to what extent that affects the regulation of muscle vascular conductance during exercise is unknown. Methods: Seven weeks of one-legged endurance training was carried out by twelve subjects. Pulmonary VO 2 during cycling and one-legged cycling was tested before and after training, while VO 2 of the trained leg (TL) and control leg (CL) during cycling was determined after training. Results:VO 2max for cycling was unaffected by training, although one-legged VO 2max became 6.7 (2.3)% (mean±SE) larger with TL than with CL. Also TL citrate synthase activity was higher [30 (12)%; P<0.05]. With the two legs working at precisely the same power during cycling at high intensity (n=8), leg oxygen uptake was 21 (8)% larger for TL than for CL (P<0.05) with oxygen extraction being 3.5 (1.1)% higher (P<0.05) and leg blood flow tended to be higher by 16.0 (7.0)% (P=0.06). Conclusion: That enhanced VO 2max for the trained leg had no implication for cycling VO 2max supports that there is a central limitation to VO 2max during whole-body exercise. However, the metabolic balance between the legs was changed during high-intensity exercise as oxygen delivery and oxygen extraction were higher in the trained leg, suggesting that endurance training ameliorates blunting of leg blood flow and oxygen uptake during whole-body exercise.

U2 - 10.1111/j.1748-1716.2011.02383.x

DO - 10.1111/j.1748-1716.2011.02383.x

M3 - Journal article

C2 - 22059600

SN - 1748-1708

VL - 205

SP - 177

EP - 185

JO - Acta Physiologica (Print)

JF - Acta Physiologica (Print)

IS - 1

ER -