The validity of cardiopulmonary exercise testing for assessing aerobic capacity in neuromuscular diseases.

OBJECTIVES: To determine the content validity of cardiopulmonary exercise testing (CPET) for assessing peak oxygen uptake (VO2peak) 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 (VO2plateau) as primary criterion, or 2 out of 3 secondary criteria; 1) peak respiratory exchange ratio (RERpeak) ≥1.10, 2), peak heart rate (HRpeak) ≥85% of predicted maximal heart rate, and 3) peak rating of perceived exertion (RPEpeak) ≥17 on the 6-20 Borg scale. These criteria were attained by 71 participants (83%). VO2plateau, RERpeak ≥1.10, HRpeak ≥85%, and RPEpeak ≥17 were attained by respectively 31%, 73%, 69%, and 72% of the participants. Peak workload, VO2peak, 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 VO2peak as a maximal aerobic capacity measure. Content validity may be lower in more severely affected people with lower physical fitness.

A Mobile Health App to Support Home-Based Aerobic Exercise in Neuromuscular Diseases: Usability Study.

BACKGROUND: Home-based aerobic exercise in people with neuromuscular diseases (NMDs) has benefits compared to exercise in the hospital or a rehabilitation center because traveling is often cumbersome due to mobility limitations, and societal costs are lower. Barriers to home-based aerobic exercise include reduced possibilities for monitoring and lack of motivation. To overcome these and other barriers, we developed a mobile health app: Keep on training with ReVi (hereafter referred to as ReVi). OBJECTIVE: We aimed to determine the usability of the ReVi app. METHODS: Patients followed a 4-month, polarized, home-based aerobic exercise program on a cycle or rowing ergometer, with 2 low-intensity sessions and 1 high-intensity session per week supported by the ReVi app. The app collected training data, including heart rate and ratings of perceived exertion, provided real-time feedback on reaching target intensity zones, and enabled monitoring via an online dashboard. Physiotherapists instructed patients on how to use the ReVi app and supervised them during their training program. Patients and physiotherapists separately evaluated usability with self-developed questionnaires, including 9 questions on a 5-point Likert scale, covering the usability elements efficiency, effectiveness, and satisfaction. RESULTS: Twenty-nine ambulatory adult patients (n=19 women; mean age 50.4, SD 14.2 years) with 11 different slowly progressive NMDs participated. Both patients and physiotherapists (n=10) reported that the app, in terms of its efficiency, was easy to use and had a rapid learning curve. Sixteen patients (55%) experienced 1 or more technical issue(s) during the course of the exercise program. In the context of effectiveness, 23 patients (81%) indicated that the app motivated them to complete the program and that it helped them to exercise within the target intensity zones. Most patients (n=19, 70%) and physiotherapists (n=6, 60%) were satisfied with the use of the app. The median attendance rate was 88% (IQR 63%-98%), with 76% (IQR 69%-82%) of time spent within the target intensity zones. Four adverse events were reported, 3 of which were resolved without discontinuation of the exercise program. CONCLUSIONS: The usability of the ReVi app was high, despite the technical issues that occurred. Further development of the app to resolve these issues is warranted before broader implementation into clinical practice.

Relationship Between Heart Rate and Perceived Exertion in Neuromuscular Diseases: How do Laboratory-Based Exercise Testing Results Translate to Home-Based Aerobic Training Sessions?

OBJECTIVE: To examine the heart rate-perceived exertion relationship between maximal exercise testing and home-based aerobic training in neuromuscular diseases. DESIGN: Multicentre randomized controlled trial, intervention group data. PARTICIPANTS: Individuals with Charcot-Marie-Tooth disease (n = 17), post-polio syndrome (n = 7) or other neuromuscular diseases (n = 6). METHODS: Participants followed a 4-month, homebased aerobic training programme guided by heart rate. Heart rate and ratings of perceived exertion (6-20 Borg Scale) were assessed for each minute during a maximal exercise test, and at the end of each exercise interval and recovery period during training. Heart rate and corresponding ratings of perceived exertion values of individual participants during training were visualized using plots, together with the exercise testing linear regression line between heart rate and ratings of perceived exertion. RESULTS: High correlation coefficients (i.e. > 0.70) were found between heart rate and ratings of perceived exertion, in all participants during testing (n = 30), and in 57% of the participants during training. Based on the plots the following distribution was found; participants reporting lower (n = 12), similar (n = 10), or higher (n = 8) ratings of perceived exertion values for corresponding heart rates during training compared with testing. CONCLUSION: Most participants had a different perception of effort for corresponding heart rates during training in comparison with exercise testing. Healthcare professionals should be aware that this may imply under- and over-training.

Measurement Properties of Aerobic Capacity Measures in Neuromuscular Diseases: A Systematic Review.

OBJECTIVE: To systematically evaluate the measurement properties of aerobic capacity measures in neuromuscular diseases. DATA SOURCES: MEDLINE, EMBASE, SportDiscus and Web of Science Conference Proceedings Citation Index - Science were systematically searched from inception until 30 June 2021. STUDY SELECTION AND DATA EXTRACTION: Screening, data extraction, risk of bias assessment and quality assessment were performed by 2 independent researchers. Studies were included if they evaluated measurement properties of aerobic capacity measures in adults with neuromuscular diseases. Risk of bias was assessed using the COnsensus based Standards for the selection of health status Measurement INstruments (COSMIN) checklist. Results were pooled and the quality of the evidence was determined using a modified Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. DATA SYNTHESIS: Nine studies including 187 participants were included in this review. Low quality of evidence was found for sufficient content validity of peak oxygen consumption through maximal exercise testing. Criterion validity of 4 out of 7 different measures to predict peak oxygen consumption was sufficient; however, quality of evidence was low or very low for all measures. No studies were found evaluating reliability or responsiveness. CONCLUSION: There was a lack of high-quality studies with sufficiently large sample sizes that evaluated the measurement properties of aerobic capacity measures in neuromuscular diseases.

The Concurrent Validity, Test-Retest Reliability and Usability of a New Foot Temperature Monitoring System for Persons with Diabetes at High Risk of Foot Ulceration.

At-home foot temperature monitoring may be useful in the early recognition of imminent foot ulcers that occur through biomechanical loading in people with diabetes. We assessed the concurrent validity, test-retest reliability, and usability of a new plantar foot temperature monitoring device in 50 people with diabetes and peripheral neuropathy. We compared plantar foot temperature measurements with a platform system that consists of embedded temperature sensors with those from a handheld infrared thermometer that was used as a reference. Repeated platform assessments were compared for test-retest reliability. Usability was assessed in 15 participants who used both devices daily for two weeks at home, after which they completed a questionnaire. Agreement between devices was excellent for the metatarsal heads and heel (ICCs ≥ 0.98, LOA: -0.89 °C; 1.16 °C) and hallux and lateral midfoot (0.93 ≤ ICC ≤ 0.96, LOA: -2.87 °C; 2.2 °C), good for digits 2-5 (0.75 ≤ ICC ≤ 0.88, LOA: -5.04 °C; 2.76 °C), and poor for the medial midfoot (ICC = 0.19, LOA: -8.21 °C; -0.05 °C). Test-retest reliability was high (ICC = 0.99, LOA: -0.59 °C; 1.35 °C). Participants scored between 3.8 and 4.3 on a 5-point Likert scale for willingness to measure, ease of use, measurement comfort, and duration. In conclusion, the platform shows good concurrent validity in foot regions where most ulcers occur, good test-retest reliability, and good usability for measuring plantar foot temperature. Further research should assess the clinical validity of the platform to help prevent plantar diabetic foot ulcers.

The Physiological, Neuromuscular, and Perceptual Response to Even- and Variable-Paced 10-km Cycling Time Trials.

BACKGROUND: During self-paced (SP) time trials (TTs), cyclists show unconscious nonrandom variations in power output of up to 10% above and below average. It is unknown what the effects of variations in power output of this magnitude are on physiological, neuromuscular, and perceptual variables. PURPOSE: To describe physiological, neuromuscular, and perceptual responses of 10-km TTs with an imposed even-paced (EP) and variable-paced (VP) workload. METHODS: Healthy male, trained, task-habituated cyclists (N = 9) completed three 10-km TTs. First, an SP TT was completed, the mean workload from which was used as the mean workload of the EP and VP TTs. The EP was performed with an imposed even workload, while VP was performed with imposed variations in workload of ±10% of the mean. In EP and VP, cardiorespiratory, neuromuscular, and perceptual variables were measured. RESULTS: Mean rating of perceived exertion was significantly lower in VP (6.13 [1.16]) compared with EP (6.75 [1.24]), P = .014. No mean differences were found for cardiorespiratory and almost all neuromuscular variables. However, differences were found at individual kilometers corresponding to power-output differences between pacing strategies. CONCLUSION: Variations in power output during TTs of ±10%, simulating natural variations in power output that are present during SP TTs, evoke minor changes in cardiorespiratory and neuromuscular responses and mostly affect the perceptual response. Rating of perceived exertion is lower when simulating natural variations in power output, compared with EP cycling. The imposed variations in workload seem to provide a psychological rather than a physiological or neuromuscular advantage.

The Role of the Rating-of-Perceived-Exertion Template in Pacing.

The rating-of-perceived-exertion (RPE) template is thought to regulate pacing and has been shown to be very robust in different circumstances. PURPOSE: The primary purpose was to investigate whether the RPE template can be manipulated by changing the race distance during the course of a time trial. The secondary purpose was to study how athletes cope with this manipulation, especially in terms of the RPE template. METHOD: Trained male subjects (N = 10) performed 3 cycling time trials: a 10-km (TT10), a 15-km (TT15), and a manipulated 15-km (TTman). During the TTman, subjects started the time trial believing that they were going to perform a 10-km time trial. However, at 7.5 km they were told that it was a 15-km time trial. RESULTS: A significant main effect of time-trial condition on RPE scores until kilometer 7.5 was found (P = .016). Post hoc comparisons showed that the RPE values of the TT15 were lower than the RPE values of the TT10 (difference 0.60; CI95% 0.11, 1.0) and TTman (difference 0.73; CI95% 0.004, 1.5). After the 7.5 km, a transition phase occurs, in which an interaction effect is present (P = .011). After this transition phase, the RPE values of TTman and TT15 did not statistically differ (P = 1.00). CONCLUSIONS: This novel distance-endpoint manipulation demonstrates that it is possible to switch between RPE templates. A clear shift in RPE during the TTman is present between the RPE templates of the TT10 and TT15. The shift strongly supports suggestions that pacing is regulated using an RPE template.