Evaluating the Test-Retest Reliability and Measurement Error of a Sit-Stand-Power Test in Individuals Treated for Cancer.

[INTRODUCTION] Muscular strength and physical function are commonly assessed in exercise oncology trials, yet muscular power is often overlooked despite being an important determinant of morbidity and mortality. The sit-to-stand power (STSp) test offers a rapid, low-cost method to evaluate lower-body power. The purpose of this study was to assess the test-retest reliability, measurement error, and minimal detectable change (MDC) of the STSp test assessed using a linear power transducer in individuals treated for cancer.

[METHODS] Adults with a history of cancer completed the STSp test on 2 occasions (2 -10 days apart), to evaluate test-retest reliability using intraclass correlation coefficients (ICC(3,1)). Standard error of measurement (SEM) and MDC were calculated.

[RESULTS] One hundred and three individuals treated for cancer (88.3% female; mean age = 60.2 ± 10.4 years) completed the test-retest assessment. The sample was racially diverse, with 51% identifying as White and 41% as Black. Breast cancer was the most common diagnosis (68.9%). Disease stage was primary early stage, with 45.6% classified as stage I and 22.3% stage II. Participants had undergone surgery (95.2%), radiation (63.1%), and chemotherapy (60.2%). The STSp test demonstrated good reliability for peak power (ICC = 0.86; 95% CI: 0.80-0.91) and average power (ICC = 0.86; 95% CI: 0.79-0.90). The peak power SEM and MDC were 199.9 W and 554.10 W, respectively. The average power SEM and MDC were 179.05 W and 496.30 W, respectively.

[CONCLUSION] The STSp test demonstrated good test-retest reliability for assessing lower-body muscular power in individuals treated for cancer. Given its low cost and feasibility, the STSp test may be useful for clinicians seeking to monitor changes in lower extremity power in oncological settings. However, the relatively large SEM and MDC values indicate substantial within-subject variability, underscoring the need for further protocol standardization.

[CLINICAL TRIAL REGISTRATION] ClinicalTrials.gov, NCT06039488.