The modified Borg cycle strength test (mBCST): Feasibility and physiological response in people with COPD and healthy older adults

Abstract

Accurate prescription of supramaximal exercise requires exercise tests covering the intensity domain between maximal aerobic and peak power output. All-out tests are commonly used for this objective but are considered challenging for people with chronic obstructive pulmonary disease (COPD) due to the extreme physiological demand. The modified Borg cycle strength test (mBCST), previously used in older adults to achieve supramaximal intensities, might be a suitable alternative in people with COPD. We aimed to determine the feasibility of the mBCST in people with COPD and to compare the physiological response with that of healthy older adults. Eighteen people with COPD and 16 age-, sex- and physical activity-matched healthy adults performed a cardiopulmonary exercise test and a mBCST. The mBCST is an incremental test [30 s:30 s cycling:rest; with individualized starting load and step size (15–50 W)] with end-of-test criteria of a rating of perceived exertion of ≥17 or cadence of <75 RPM for >5 s. Feasibility was assessed using a framework covering the aim, interpretability, familiarity, duration, scoring/completion complexity, costs and safety. Measurements of external exercise intensity, rating of perceived exertion, symptoms and cardiorespiratory demand were obtained. The mBCST was deemed feasible according to the feasibility framework. Expressed relative to the cardiopulmonary exercise test, the participants reached supramaximal external exercise intensities during the mBCST [COPD, 145 (125–168)%; healthy, 154 (148–163)%], without differences in intensity or physiological response between groups (p > 0.05). The mBCST is feasible in people with COPD and enables supramaximal external exercise intensities, with similar physiological response to healthy older adults. The mBCST could be considered when selecting an exercise test to prescribe supramaximal exercise.