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Erschienen in:
11.05.2017 | Original Article
Physiological responses to incremental, interval, and continuous counterweighted single-leg and double-leg cycling at the same relative intensities
Erschienen in: European Journal of Applied Physiology | Ausgabe 7/2017
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Purpose
We compared physiological responses to incremental, interval, and continuous counterweighted single-leg and double-leg cycling at the same relative intensities. The primary hypothesis was that the counterweight method would elicit greater normalized power (i.e., power/active leg), greater electromyography (EMG) responses, and lower cardiorespiratory demand.
Methods
Graded-exercise tests performed by 12 men (age: 21 ± 2 years; BMI: 24 ± 3 kg/m2) initially established that peak oxygen uptake (\(\dot{V}{\text{O}}_{2} {\text{peak}}\); 76 ± 8.4%), expired ventilation (\(\dot{V}_{\text{E}} {\text{peak}}\); 71 ± 6.8%), carbon dioxide production (\(\dot{V}{\text{CO}}_{2} {\text{peak}}\); 71 ± 6.8%), heart rate (HRpeak; 91 ± 5.3%), and power output (PPO; 56 ± 3.6%) were lower during single-leg compared to double-leg cycling (main effect of mode; p < 0.05). On separate days, participants performed four experimental trials, which involved 30-min bouts of either continuous (50% PPO) or interval exercise [4 × (5-min 65% PPO + 2.5 min 20% PPO)] in a single- or double-leg manner.
Results
Double-leg interval and continuous cycling were performed at greater absolute power outputs but lower normalized power outputs compared to single-leg cycling (p < 0.001). The average EMG responses from the vastus lateralis and vastus medialis were similar across modes (p > 0.05), but semitendinosus was activated to a greater extent for single-leg cycling (p = 0.005). Single-leg interval and continuous cycling elicited lower mean \(\dot{V}_{\text{E}}\), \(\dot{V}{\text{O}}_{2}\), \(\dot{V}{\text{CO}}_{2}\), HR and ratings of perceived exertion compared to double-leg cycling (p < 0.05).
Conclusions
Counterweighted single-leg cycling elicits lower cardiorespiratory and perceptual responses than double-leg cycling at greater normalized power outputs.