Veneman T; Amsterdam UMC location University of Amsterdam, Rehabilitation Medicine, Meibergdreef 9, Amsterdam, The Netherlands
Koopman FS; Oorschot S;de Koning JJ; Bongers BC; Nollet F; Voorn EL;

Archives of physical medicine and rehabilitation [Arch Phys Med Rehabil] 2024 Jul 19.
Date of Electronic Publication: 2024 Jul 19.

Objectives: To determine the content validity of cardiopulmonary exercise testing (CPET) for assessing peak oxygen uptake (VO _2peak ) in neuromuscular diseases (NMD).
Design: Baseline assessment of a randomized controlled trial.
Setting: Academic hospital.
Participants: Eighty-six adults (age: 58.0 ± 13.9 years) with Charcot-Marie-Tooth disease (n=35), post-polio syndrome (n=26), or other NMD (n=25).
Intervention: Not applicable.
Main Outcome Measures: Workload, gas exchange variables, heart rate, and ratings of perceived exertion were measured during CPET on a cycle ergometer, supervised by an experienced trained assessor. Muscle strength of the knee extensors was assessed isometrically with a fixed dynamometer. Criteria for confirming maximal cardiorespiratory effort during CPET were established during 3 consensus meetings with an expert group. The percentage of participants meeting these criteria was assessed to quantify content validity.
Results: The following criteria were established for maximal cardiorespiratory effort; a plateau in oxygen uptake (VO _2plateau ) as primary criterion, or 2 out of 3 secondary criteria; 1) peak respiratory exchange ratio (RER _peak ) ≥1.10, 2), peak heart rate (HR _peak ) ≥85% of predicted maximal heart rate, and 3) peak rating of perceived exertion (RPE _peak ) ≥17 on the 6-20 Borg scale. These criteria were attained by 71 participants (83%). VO _2plateau , RER _peak ≥1.10, HR _peak ≥85%, and RPE _peak ≥17 were attained by respectively 31%, 73%, 69%, and 72% of the participants. Peak workload, VO _2peak , and knee extension muscle strength were significantly higher, and body mass index was lower (all p<0.05), in participants with maximal cardiorespiratory effort compared to other participants.
Conclusions: Most people with NMD achieved maximal cardiorespiratory effort during CPET. Therewith, this study provides high quality evidence of sufficient content validity of VO _2peak as a maximal aerobic capacity measure. Content validity may be lower in more severely affected people with lower physical fitness.