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Introduction: The recently developed daily and clinical visit PROactive physical activity in COPD (PPAC) instruments are hybrid tools to objectively quantify the level of physical activity and the difficulties experienced in everyday life. Our aim was to translate these instruments for the French-speaking chronic obstructive pulmonary disease (COPD) community worldwide and evaluate the influence of weather and pollution on difficulty score., Methods: The translation procedure was conducted following the guidelines for cross-cultural adaptation process. The translated clinical visit (C-PPAC) was tested among COPD patients in France. A retest was conducted after an interval of at least 2 weeks. The C-PPAC difficulty score was then tested to see how sensitive it was to the influence of weather and outdoor pollution., Results: One hundred and seventeen COPD patients (age 65±9 years; FEV1: 51±20%) from 9 regions in France were included. The French version of C-PPAC was found comprehensible by the patients with an average score of 4.8/5 on a Likert-scale. It showed good internal consistency with Cronbach's α>0.90 and a good test retest reliability with an intraclass correlation coefficient of ≥0.80. The difficulty score was negatively correlated with duration of daylight ( ρ =-0.266; p <0.01) and influenced by the intensity of rainfall (light vs. heavy rainfall: 68±16 vs. 76±14 respectively, p =0.045). The score was lower in patients receiving long term oxygen therapy (60±15 vs. 71±15, p <0.01), but not correlated with the pollution indices., Conclusion: The French versions of the questionnaires of the PPAC instruments are accepted and comprehensible to COPD patients. The difficulty score of C-PPAC is sensitive to duration of daylight and rainfall. Such weather factors must be taken into consideration when evaluating the physical activity behavior using these tools in COPD., Competing Interests: The authors report no conflicts of interest in this work., (© 2020 Vaidya et al.)

Background: Measurement of quadriceps muscular force is recommended in individuals with COPD, notably during a pulmonary rehabilitation program (PRP). However, the tools used to measure quadriceps maximal voluntary contraction (QMVC) and the clinical relevance of the results, as well as their interpretation for a given patient, remain a matter of debate. The objective of this study was to estimate the minimally important difference (MID) of QMVC using a fixed dynamometer in individuals with COPD undergoing a PRP., Methods: Individuals with COPD undergoing a PRP were included in this study. QMVC was measured using a dynamometer (MicroFET2) fixed on a rigid support according to a standard-ized methodology. Exercise capacity was measured by 6-minute walk distance (6MWD) and evaluation of quality of life with St George's respiratory questionnaire (SGRQ) and Hospital Anxiety and Depression Scale (HADS) total scores. All measures were obtained at baseline and the end of the PRP. The MID was calculated using distribution-based methods., Results: A total of 157 individuals with COPD (age 62.9±9.0 years, forced expiratory volume in 1 second 47.3%±18.6% predicted) were included in this study. At the end of the PRP, the patients had improved their quadriceps force significantly by 8.9±15.6 Nm ( P <0.001), as well as 6MWD by 42±50 m ( P <0.001), SGRQ total score by -9±17 ( P <0.001) and HADS total score by -3±6 ( P <0.001). MID estimation using distribution-based analysis was 7.5 Nm by empirical rule effect size and 7.8 Nm by Cohen's effect size., Conclusion: Measurement of QMVC using a fixed dynamometer is a simple and valuable tool capable of assessing improvement in quadriceps muscle force after a PRP. We suggest an MID of 7.5 Nm to identify beneficial changes after a PRP intervention., Competing Interests: Disclosure The authors report no conflicts of interest in this work.