Evaluation of Hand Muscle Strength Using Manual Dynamometry: A Reliability and Validity Study of the Activ5 Instrument

Manual dynamometry (HHD) allows for the assessment of musculature because its use has been supported as an indicator of health in different population groups. The objective of this study was to examine the reliability and validity of the Activ5 dynamometer for assessing grip strength in a population of adults. A total of 106 individuals with an age of 20.38 ± 1.64, body mass of 71.52 ± 11.32 kg, and height of 1.70 ± 0.11 m were evaluated during two sessions. A cross-sectional agreement study was conducted on Sports Science students from a university community, and 106 individuals were evaluated during two sessions. Statistical analysis of reliability and validity was performed using intraclass correlation coefficients (ICCs), Pearson correlations, and Lin’s coefficient. According to Lin’s coefficient, both instruments measure grip strength for both conditions, either for the right hand or the left hand. The correlation coefficient to determine the linear relationship between both instruments determined that between the Jamar right-hand dynamometer and the right-hand Activ5, a coefficient R2 = 0.580, p = 0.00, was obtained. In contrast, the correlation between the Jamar left-hand dynamometer and the left-hand Activ5 had a coefficient R2 = 0.543, p = 0.001. Both intraclass correlation coefficients and Cronbach’s alpha presented high values, indicating that both instruments have good reproducibility in their measurements. The Activ5 dynamometer cannot be used interchangeably with the Jamar dynamometer; however, the close values reported make it a reliable tool in grip strength assessment. The different characteristics of the Activ5 instrument, such as its ergonomics, weight, portability, wireless connection, dimensions, and applications, make it a promising daily- use tool for assessing, monitoring, and the prescription of physical activity and exercise.