Isotonic quadriceps endurance is better associated with daily physical activity than quadriceps strength and power in COPD: an international multicentre cross-sectional trial

Abstract

Knowledge about modifiable determinants of daily physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD) is crucial to design effective PA interventions. The present study aimed to determine the contribution of quadriceps strength, power and endurance to daily PA in COPD. Additionally, for quadriceps endurance, we also aimed to determine to what extent the association varies according to the mode of movement (isotonic, isometric, or isokinetic). Using a multicentre cross-sectional trial design we determined the contribution of quadriceps function to daily PA (steps, sedentary time and time spent doing moderate-to-very-vigorous physical activity [MVPA]) using bivariate and partial Pearson correlation analysis (r) and multiple linear regression models (ΔR2). Pre-determined controlling factors were sex, age, body mass index (BMI), COPD-assessment test, forced expiratory volume in one second in percent of the predicted value (FEV1pred), and distance walked on the 6-minute walk test. Eighty-one patients with COPD (mean ± SD: age 67 ± 8 years, FEV1pred 57 ± 19%, daily steps 4968 ± 3319, daily sedentary time 1016 ± 305 min, and MVPA time 83 ± 45 min) were included. Small to moderate bivariate correlations (r = .225 to .452, p < .05) were found between quadriceps function and measures of PA. The best multiple linear regression models explained 38–49% of the variance in the data. Isotonic endurance was the only muscle contributor that improved all PA models; daily steps (ΔR2 = .04 [relative improvement 13%] p = .026), daily sedentary time (ΔR2 = .07 [23%], p = .005) and MVPA-minutes (ΔR2 = .08 [20%], p = .001). Isotonic endurance was also independently associated with most PA variables, even when controlling for strength, power or isometric-isokinetic endurance properties of the muscle (r = .246 to .384, p < .05). In contrast, neither strength, power, isometric-or isokinetic endurance properties of the muscle was independently associated with PA measures when controlling for isotonic endurance (r = .037 to .219, p > .05). To conclude, strength, power, and endurance properties of the quadriceps were low to moderately associated with PA in patients with COPD. Isotonic quadriceps endurance was the only quadriceps property that was independently associated with the different measures of PA after controlling for a basic set of known determinants of PA, quadriceps strength or power, or isometric or isokinetic quadriceps endurance. Future longitudinal studies should investigate its potential as a modifiable determinant of PA.

Influencing factors of sedentary behaviour in people with chronic obstructive pulmonary disease: a systematic review

“…A study by Frykholm et al found that increased isotonic quadriceps endurance is associated with reduced sedentary time. 44 …”

To Act or Not to Act—a Sense of Control Is Important for People With Chronic Obstructive Pulmonary Disease to Increase Physical Activity: Grounded Theory Study

“…Evidence suggests that people with COPD avoid participation in PA owing to the perception of breathlessness, leading to a vicious circle of muscle deconditioning, further compromising their capacity to engage in PA [3,[9][10][11][12]. However, improving the level of PA in people with COPD is complex, as PA behavior itself is complex and multifaceted, including, for example, personal, physiological, and psychological elements as well as social and environmental factors [1,13,14].…”

“…Notably, despite the wide range of available methods, their effect on PA in patients with COPD is limited, which might be attributed to an incomplete understanding of the determinants of PA behavior in the COPD population [12,15]. Although a variety of determinants of PA have been identified, including, but not limited to, exercise capacity, previous exacerbations, dyspnea, quadriceps dysfunction, and hyperinflation [11,[15][16][17], the available information does not clearly answer the determinants of PA in patients with COPD. This is mostly because the available research has been cross-sectional [15].…”

Muscle Power in Patients with Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-analysis

“…Moreover, muscle power showed a stronger association with functional performance than muscle strength in healthy older adults and patients with neurological diseases [7][8][9]. Similarly, cross-sectional studies have found associations between muscle power and functional performance [10,11] or physical activity [12,13] in individuals with COPD. However, to the best of our knowledge, only one study has reported reduced lower extremity peak power in older adults with COPD compared with healthy subjects so far [14].…”