OBJECTIVE: This study aimed to evaluate the intrarater and interrater reliability of isometric quadriceps femoris strength (IQS) using a portable dynamometer in patients with chronic obstructive pulmonary disease (COPD) and to verify their tolerance to the protocol. METHODS: A cross-sectional reliability study was conducted with 50 patients with stable COPD (34 men and 16 women; mean age = 69 7 [SD = 8]). The main outcome measure was obtained using a portable dynamometer (Microfet 2®) to assess IQS. Two blind raters performed 2 assessments in the dominant lower limb in 2 nonconsecutive days. The intraclass correlation coefficient (ICC) was used to verify the intrarater and interrater reliability, and it was considered excellent when ICC > 0.90, with a 5% significance level. RESULTS: Rater 1 and 2 intrarater reliability was as follows: ICC = 0.96 (95% CI = 0.94 to 0.98) and ICC = 0.97 (95% CI = 0.95 to 0.98), respectively. The interrater reliability was as follows: ICC = 0.96 (95% CI 0.93 to 0.98). The minimum detectable difference (MDD) was 4 to 5 kgF, in mean, for intrarater and interrater reliability. Not all patients presented relevant changes in physiological responses, dyspnea and lower limb fatigue. CONCLUSION: There was an excellent intrarater and interrater reliability for IQS, and the patients tolerated the protocol. IMPACT: This tool can be used to assess quadriceps strength in clinical practice in patients with COPD.
OBJECTIVE: This study aimed to evaluate the intrarater and interrater reliability of isometric quadriceps femoris strength (IQS) using a portable dynamometer in patients with chronic obstructive pulmonary disease (COPD) and to verify their tolerance to the protocol. METHODS: A cross-sectional reliability study was conducted with 50 patients with stable COPD (34 men and 16 women; mean age = 69 7 [SD = 8]). The main outcome measure was obtained using a portable dynamometer (Microfet 2®) to assess IQS. Two blind raters performed 2 assessments in the dominant lower limb in 2 nonconsecutive days. The intraclass correlation coefficient (ICC) was used to verify the intrarater and interrater reliability, and it was considered excellent when ICC > 0.90, with a 5% significance level. RESULTS: Rater 1 and 2 intrarater reliability was as follows: ICC = 0.96 (95% CI = 0.94 to 0.98) and ICC = 0.97 (95% CI = 0.95 to 0.98), respectively. The interrater reliability was as follows: ICC = 0.96 (95% CI 0.93 to 0.98). The minimum detectable difference (MDD) was 4 to 5 kgF, in mean, for intrarater and interrater reliability. Not all patients presented relevant changes in physiological responses, dyspnea and lower limb fatigue. CONCLUSION: There was an excellent intrarater and interrater reliability for IQS, and the patients tolerated the protocol. IMPACT: This tool can be used to assess quadriceps strength in clinical practice in patients with COPD.