Validity and reliability of SEIS-3: An instrument for subjective measuring of strength in older adults

The use of rating of perceived exertion (RPE) has grown substantially, providing a valuable alternative for exercise intensity monitoring, especially for older adults. However, some challenges, such as cross-cultural validity, age-related differences, and reliability issues, necessitate the development of a concise and user-friendly RPE instrument, particularly for strength training in this population. This study aimed to validate the Subjective Effort Induction Scale (SEIS-3), a simplified tool for measuring effort during strength training. SEIS-3 is a graded instrument with three exertion levels: 1) Light effort, 2) Moderate effort, and 3) Strong effort. Twenty seniors, aged 71±7 years, of both genders participated in the study (CEP/Unimontes 2,741,071/2018). We collected maximal isometric voluntary contraction (MIVC) data using a digital dynamometer. Subsequently, participants underwent the initial test, following the three SEIS-3 categories in a randomly assigned order of induced subjective effort. SEIS-3 instrument was evaluated by the approaches:•Linear regression analysis: employed to assess the validity of the instrument.•Intraclass Correlation Coefficient (ICC): employed to assess the reliability of the instrument.SEIS-3 effort categories correlated with MIVC in both hands (R²=0.80, F = 25.596, df=3, p < 0.01 for right hand; R²=0.56, F = 9.132, p < 0.01 for left hand). Test-retest reliability for grip strength across effort categories was excellent (ICC > 0.9). SEIS-3 is a valid and reliable user-friendly tool for accurately assessing and regulating exercise intensity in older adults during strength tasks, benefiting their health, functional capacity, and overall quality of life. This low-cost instrument can help health professionals in their activities.