Validation and reliability of a new PC-controlled device for the evaluation of key pinch strength in healthy adults
Objective: Hand muscle strength assessment is widespread and can be a useful marker in the evaluation and monitoring of subjects at different ages and health conditions. This study aimed at validating and determining the reliability of a new digital device for evaluation of hand pinch strength by comparing it with a well-validated hand strength assessment device, the Jamar hydraulic hand dynamometer. Methods: In 65 healthy subjects, (males / females: 29 / 36), mean age 40.3±18.0 (range: 19.3 - 76.5) years, hand pinch strength and hydraulic hand dynamometer were used to assess hand strength following a testing protocol. Only the dominant hand was tested. Evaluations were performed considering gender, hand dominance, body mass index and age, according to the standardized testing protocol. The mean of three consecutive grip tests and lateral pinch tests was recorded. Results: There was a strong correlation (p<0.0001) between the hydraulic hand dynamometer and hand pinch strength tests. Both mean strengths measured by hydraulic hand dynamometer and hand pinch strength in females were significantly lower than in males (P<0.001), the grip strength being 34.75% and the lateral pinch test 27.83% weaker than in males. Multivariate analysis indicated that the strength expressed by the hand pinch strength pinch test remained significantly associated with the results of hydraulic hand dynamometer (p<0,001), independent of age and body weight. Conclusions: hand pinch strength and hydraulic hand dynamometer have been shown to be significantly correlated with each other in subjects of different ages, sex and body mass index. The hand pinch strength device has been proven to be a reliable tool for measuring maximal isometric strength by lateral pinch test. This device can be used for quick and inexpensive numerical evaluation of muscular strength in cases as the elderly in communities, bedridden patients, and during drug therapies presumed to be strength affecting.