Maximum voluntary isometric pinch contraction and force-matching from the fourth to the eighth decades of life

Abstract

Understanding the effects of age and gender on pinch strength, variability, and accuracy and how one's hand function changes with age better enables those in the preventative and rehabilitative fields to combat these losses. The present study examined fine motor maximum pinch strength [maximum voluntary isometric contraction (MVIC)] as well as the ability to maintain 5% MVIC accurately and consistently in five decades. One hundred adults in five groups, 20 in each decade of life from 30 to 79 years old, were nonrandomly recruited from the community. A two-way analysis of variance applied to MVIC, and a two-way multivariate analysis of variance applied to the variability (coefficient of variability) and accuracy (root mean square error), plus correlation and regression analyses, were used to determine decade and gender effects on pinch force. The task involved using isometric pinch control of a computer cursor to match a 5% of MVIC force level represented by a horizontal line. MVIC and force-matching steadiness and accuracy across all ages were not significantly different until the eighth decade (P<0.01). Men were stronger (P<0.001) but performed low-level force-matching with greater error (P<0.001) than women. Strength was not correlated with steadiness but was weakly correlated with accuracy (r=0.293, P<0.01), and steadiness and accuracy were strongly correlated (r=0.783, P<0.001). Decade and gender were moderate and strong predictors of accuracy and steadiness, respectively. In conclusion, age and gender differences were evident in pinch-force strength and control.