BackgroundTelecoaching approaches can enhance physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD). However, their effectiveness is likely to be influenced by intervention-specific characteristics.ObjectiveThis study aimed to assess the acceptability, actual usage, and feasibility of a complex PA telecoaching intervention from both patient and coach perspectives and link these to the effectiveness of the intervention.MethodsWe conducted a mixed-methods study based on the completers of the intervention group (N=159) included in an (effective) 12-week PA telecoaching intervention. This semiautomated telecoaching intervention consisted of a step counter and a smartphone app. Data from a project-tailored questionnaire (quantitative data) were combined with data from patient interviews and a coach focus group (qualitative data) to investigate patient and coach acceptability, actual usage, and feasibility of the intervention. The degree of actual usage of the smartphone and step counter was also derived from app data. Both actual usage and perception of feasibility were linked to objectively measured change in PA.ResultsThe intervention was well accepted and perceived as feasible by all coaches present in the focus group as well by patients, with 89.3% (142/159) of patients indicating that they enjoyed taking part. Only a minority of patients (8.2%; 13/159) reported that they found it difficult to use the smartphone. Actual usage of the step counter was excellent, with patients wearing it for a median (25th-75th percentiles) of 6.3 (5.8-6.8) days per week, which did not change over time (P=.98). The smartphone interface was used less frequently and actual usage of all daily tasks decreased significantly over time (P<.001). Patients needing more contact time had a smaller increase in PA, with mean (SD) of +193 (SD 2375) steps per day, +907 (SD 2306) steps per day, and +1489 (SD 2310) steps per day in high, medium, and low contact time groups, respectively; P for-trend=.01. The overall actual usage of the different components of the intervention was not associated with change in step count in the total group (P=.63).ConclusionsThe 12-week semiautomated PA telecoaching intervention was well accepted and feasible for patients with COPD and their coaches. The actual usage of the step counter was excellent, whereas actual usage of the smartphone tasks was lower and decreased over time. Patients who required more contact experienced less PA benefits.Trial RegistrationClinicalTrials.gov NCT02158065; http://clinicaltrials.gov/ct2/show/NCT02158065 (Archived by WebCite at http://www.webcitation.org/73bsaudy9)

PurposePulmonary rehabilitation (PR) enhances exercise tolerance in patients with COPD; however, improvements in physical activity (PA) are not guaranteed. This study explored the relationship between baseline exercise tolerance and changes in PA after PR.Materials and methodsPatient data from prospective clinical trials in the PR settings of Athens and Leuven (2008–2016) were analyzed. Validated PA monitors were worn for 1 week before and after a 12-week program. The proportion of patients who improved PA levels ≥1,000 steps/day (“PA responders”) after PR was compared between those with initial 6-minute walk distance [6MWDi] <350 m and ≥350 m. Baseline predictors of PA change were evaluated via univariate and multivariate logistic regression analyses.ResultsTwo hundred thirty-six patients with COPD (median [IQR] FEV1 44 [33–59] % predicted, age 65±8 years, 6MWDi 416 [332–486] m) were included. The proportion of “PA responders” after PR was significantly greater in those with higher vs lower 6MWDi (37.9% vs 16.4%, respectively; P<0.001). 6MWDi group classification was the strongest baseline independent predictor of PA improvement (univariate OR 3.10, 95% CI 1.51–6.36).ConclusionThe likelihood of improving PA after PR is increased with greater 6MWDi. Baseline exercise tolerance appears as an important stratification metric for future research in this field.

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BackgroundThe development of contractile muscle fatigue (CMF) affects training responses in patients with COPD. Downhill walking induces CMF with lower dyspnoea and fatigue than level walking. This study compared the effect of pulmonary rehabilitation (PR) comprising downhill walking training (DT) to PR comprising level walking (conventional training, CT) in patients with COPD.MethodsIn this randomised controlled trial, thirty five patients (62±8 years; FEV1 50±17%pred) were randomised to DT or CT. Exercise tolerance (6-minute walk test distance, 6MWD [primary outcome]), muscle function, symptoms, quality-of-life and physical activity levels were assessed before and after PR. Absolute training changes and the proportion of patients exceeding the 30 m 6MWD minimally important difference (MID) were compared between groups. Quadriceps muscle biopsies were collected after PR in a subset of patients to examine physiological responses to long-term eccentric training.ResultsNo between-group differences were observed in absolute 6MWD improvement (mean 6MWD Δ77±46 m DT versus 56±47 m CT; p=0.45), however 94% of patients in DT exceeded the 6MWD MID compared to 65% in CT (p=0.03). Patients in DT tended to have larger improvements than CT in other outcomes. Muscle biopsy analyses did not differ between groups.ConclusionPR incorporating downhill walking confers similar magnitudes of effects to PR with conventional walking across clinical outcomes in patients with COPD, however offers a more reliable stimulus to maximise the achievement of clinically relevant gains in functional exercise tolerance in people with COPD.

This study investigated the validity and reliability of fixed strain gauge measurements of isometric quadriceps force in patients with chronic obstructive pulmonary disease (COPD). A total cohort of 138 patients with COPD were assessed. To determine validity, maximal volitional quadriceps force was evaluated during isometric maximal voluntary contraction (MVC) manoeuvre via a fixed strain gauge dynamometer and compared to (a) potentiated non-volitional quadriceps force obtained via magnetic stimulation of the femoral nerve (twitch (Tw); n = 92) and (b) volitional computerized dynamometry (Biodex; n = 46) and analysed via correlation coefficients. Test–retest and absolute reliability were determined via calculations of intra-class correlation coefficients (ICCs), smallest real differences (SRDs) and standard errors of measurement (SEMs). For this, MVC recordings in each device were performed across two test sessions separated by a period of 7 days (n = 46). Strain gauge measures of MVC demonstrated very large correlation with Tw and Biodex results (r = 0.86 and 0.88, respectively, both p < 0.0001). ICC, SEM and SRD were numerically comparable between strain gauge and Biodex devices (ICC = 0.96 vs. 0.93; SEM = 8.50 vs. 10.54 N·m and SRD = 23.59 vs. 29.22 N·m, respectively). The results support that strain gauge measures of quadriceps force are valid and reliable in patients with COPD.