Investigation of cardiopulmonary exercise testing using a dynamic leg press and comparison with a cycle ergometer

Abstract

BackgroundLeg-press machines are widely employed for musculoskeletal conditioning of the lower-limbs and they provide cardiovascular benefits for resistance training in cardiac patients. The aim of this study was to assess the feasibility of a dynamic leg press (DLP) for incremental cardiopulmonary exercise testing (CPET) and to compare the results with those obtained using a cycle ergometer (CE).MethodsTwelve healthy participants aged 27±4 years (mean ± standard deviation) performed incremental cardiopulmonary exercise tests on a DLP and on a CE. To facilitate CPET, the DLP was augmented with force and angle sensors, a work rate estimation algorithm, and a visual feedback system. Gas exchange variables and heart rate were recorded breath-by-breath using a cardiopulmonary monitoring system.ResultsPeak oxygen uptake and peak heart rate were significantly lower for the DLP than for the CE: peak oxygen uptake was 3.2±0.5 vs. 4.1±0.5 L/min (DLP vs. CE, p=6.7×10−6); peak heart rate was 174±14 vs. 182±13 bpm (DLP vs. CE, p=0.0016). Likewise, the sub-maximal cardiopulmonary parameters, viz. the first and second ventilatory thresholds, and ramp duration were significantly lower for the DLP.ConclusionsThe dynamic leg press was found to be feasible for CPET: the approach was technically implementable and all peak and sub-maximal cardiopulmonary parameters were able to be identified. The lower outcome values observed with the DLP can be attributed to a peripheral factor, namely the earlier onset of muscular fatigue.

Technical feasibility of constant-load and high-intensity interval training for cardiopulmonary conditioning using a re-engineered dynamic leg press

“…Four participants performed the training sessions for both CLT and HIIT based on their targetV O 2VT1 anḋ V O 2VT2 obtained from the previous incremental tests [18]. One participant (participant 1) could not complete the training sessions based on the target outcomes from the incremental test [18].…”

“…Four participants performed the training sessions for both CLT and HIIT based on their target and obtained from the previous incremental tests [ 18 ]. One participant (participant 1) could not complete the training sessions based on the target outcomes from the incremental test [ 18 ]. It was suspected that these outcomes were overestimated, therefore this participant had to re-perform the incremental test where the outcomes were found to be lower than those obtained from the first incremental test.…”

“…These engineering modifications facilitated accurate work rate calculation, and allowed participants to see their exercise work rate and adjust their volitional effort to meet the target work rate. This approach was previously shown to be feasible for incremental cardiopulmonary exercise testing in healthy participants [18].…”

“…The use of ventilatory thresholds for exercise prescription is recommended [ 13 – 15 ] because, unlike the maximal capacity percentage, ventilatory thresholds are independent of participants’ motivation [ 16 ] and the duration of the exercise testing protocol [ 17 ]. It was reported previously that a dynamic leg-press is feasible for incremental cardiopulmonary exercise testing, and the substantial cardiopulmonary responses allowed the identification of peak and sub-maximal parameters with a high rate of success [ 18 ].…”

“…Leg-press training devices allow the performance of resistive exercise, where eccentric and concentric work regimes are combined [ 18 , 19 ]; this has been proven to provide important physiological benefits [ 20 – 22 ]. They are mainly used for musculoskeletal conditioning [ 23 ], and showed potential for neuromuscular rehabilitation applications [ 24 ].…”