Lower-limb muscle function is a determinant of exercise tolerance after lung resection surgery in patients with lung cancer.

This study aims to investigate the association between exercise tolerance, pulmonary function and lower-limb muscle function in patients with lung cancer who underwent lung resection surgery in the previous year. Sixty-four patients (age: 67 ± 11 years, 66% males) performed a symptom-limited incremental cycle test to define peak oxygen consumption (VO2 peak) and peak workload (Wpeak). The best of two 6-min walking distance (6MWD) tests was also included. Isometric quadriceps strength and isokinetic quadriceps endurance were measured. Post-bronchodilator spirometry, lung volumes and diffusing capacity of the lung for carbon monoxide (DLCO ) measurements were assessed. Univariate correlation analysis and multiple regression analyses were performed. VO2 peak, W peak and 6MWD showed moderate to strong correlations with quadriceps strength/endurance and DLCO while weak to moderate correlations were found with forced expiratory volume in 1 s (FEV1) , functional residual capacity (FRC) and body weight. Multiple regression showed that peak isometric quadriceps strength (P < 0.001) and DLCO (P < 0.001) were significant predictors of VO2 peak (explained variance R2  = 0.67), while quadriceps endurance (P = 0.0015) and DLCO (P < 0.0001) were significant predictors of W peak (R2  = 0.61). Quadriceps endurance capacity (P = 0.013), but not DLCO , significantly contributed to the 6MWD model (R2  = 0.29). We identified a strong significant relationship between peak aerobic capacity and quadriceps muscle function and lung diffusing capacity. 6MWD was significantly related to quadriceps muscle function but not to pulmonary function. These findings suggest that accurate assessment of lower-limb muscle strength has a role in the accurate interpretation of exercise tests and in selecting optimal candidates for resistance training interventions targeting the lower-limb muscles after resection surgery.

Burtin C ，Franssen FME ，Vanfleteren LEGW ，Groenen MTJ ，Wouters EFM ，Spruit MA ... -  《-》

Specific Contribution of Quadriceps Muscle Strength, Endurance, and Power to Functional Exercise Capacity in People With Chronic Obstructive Pulmonary Disease: A Multicenter Study.

Various functional muscle properties affect different aspects of functional exercise capacity in people with chronic obstructive pulmonary disease (COPD). The purpose of this study was to investigate the contribution of quadriceps muscle strength, endurance, and power to 6-Minute Walking Distance (6MWD) and 1-minute sit-to-stand test (1STS) performance in people with COPD. The study was a prospective, multicenter, cross-sectional study. Anthropometrics, Medical Research Council dyspnea scale, lung function, 6MWD, and 1STS number of repetitions were assessed. Isometric quadriceps strength and endurance, isotonic quadriceps endurance, isokinetic quadriceps strength, and power were assessed on a computerized dynamometer while functional quadriceps power was determined during 5 sit-to-stand repetitions. Univariate and multivariate analyses were performed to determine the contribution of functional muscle properties to the 6MWD and the 1STS number of repetitions. The study included 70 people with COPD (mean % predicted forced expiratory volume in 1 second = 58.9 [SD = 18.2]). The 6MWD correlated with each functional muscle property except the isometric quadriceps endurance. The number of repetitions during the 1STS correlated with each functional muscle property except isometric measurements. Multivariate models explained 60% and 39% of the variance in the 6MWD and 1STS number of repetitions, respectively, with quadriceps power determined during 5 sit-to-stand repetitions being the muscle functional property with the strongest contribution to the models. Except for isometric endurance, quadriceps strength, endurance, and power were associated with functional exercise capacity in people with moderate COPD. Among these functional muscle properties, muscle power contributed the most to the 6MWD and 1STS number of repetitions, suggesting that muscle power is more relevant to functional exercise capacity than muscle strength or endurance in people with COPD. Understanding the individual contribution of muscle properties to functional status is important to designing interventions. This study provides the guidance that muscle power may be more important to functional exercise capacity than muscle strength or endurance in people with COPD.

Gephine S ，Frykholm E ，Nyberg A ，Mucci P ，Van Hees HWH ，Lemson A ，Klijn P ，Maltais F ，Saey D ... -  《-》

The correlation between quadriceps muscle strength and endurance and exercise performance in patients with COPD.

Vaes AW ，Sillen MJH ，Goërtz YMJ ，Machado FVC ，Van Herck M ，Burtin C ，Franssen FME ，van 't Hul AJ ，Spruit MA ... -  《-》

Relationship between peripheral muscle structure and function in patients with chronic obstructive pulmonary disease with different nutritional status.

Malaguti C ，Napolis LM ，Villaça D ，Neder JA ，Nery LE ，Dal Corso S ... -  《-》

The 1-Minute Sit-to-Stand Test in Adults With Cystic Fibrosis: Correlations With Cardiopulmonary Exercise Test, 6-Minute Walk Test, and Quadriceps Strength.

Exercise testing is part of the regular assessment of patients with cystic fibrosis (CF). We aimed to evaluate (1) the convergent validity of the 1-min sit-to-stand (STS) test in CF by investigating its relationships with peak oxygen uptake (peak V̇O2 ), quadriceps strength, and quality of life and (2) to compare these associations with those of the 6-min walk test (6MWT). Twenty-five adults with CF (FEV1 = 59 ± 24%) performed the STS test, the 6MWT, quadriceps strength assessment, and cardiopulmonary exercise test (CPET). Physical activity level, quality of life, and self-esteem were assessed by questionnaires. STS repetitions, 6-min walk distance, quadriceps strength, and peak V̇O2 were, respectively, 71 ± 12, 90 ± 10, 93 ± 29, and 62 ± 16% of predicted. The STS test had moderate associations with peak V̇O2 (r = 0.56, P = .004), quadriceps strength (r = 0.52, P = .008), and some questionnaire items (eg, perceived physical strength, r = 0.67, P < .001) only when repetitions were expressed as a product of body weight. Overall, these associations were weaker than those obtained from 6-min walk distance × weight. Oxygen desaturation during the STS test was strongly associated with oxygen desaturation during CPET (r = 0.80, P < .001). Peak heart rate was lower during the STS test as compared with CPET (P < .001) and the 6MWT (P = .009). The STS test cannot be used as a replacement for CPET to accurately assess peak exercise capacity in CF. The STS test may have utility in detecting patients with CF who may exhibit a high level of oxygen desaturation during heavy exercise. Further studies should identify the factors contributing to STS performance to confirm the potential interest of STS repetitions × body weight outcome as a useful submaximal exercise parameter in CF.

Gruet M ，Peyré-Tartaruga LA ，Mely L ，Vallier JM ... -  《-》