Age-related changes in multi-finger interactions in adults during maximum voluntary finger force production tasks

Oliveira, M. A., et al., Age-related changes in multi-finger interactions
in adults ..., Human Movement Science (2008),
doi:10.1016/j.humov.2008.04.005

abstract:
This study aimed to continue our characterization of finger
strength and multi-finger interactions across the lifespan to
include those in their 60s and older. Building on our previous study
of children, we examined young and elderly adults during isometric
finger flexion and extension tasks. Sixteen young and 16 elderly,
gender-matched participants produced maximum force using
either a single finger or all four fingers in flexion and extension.
The maximum voluntary finger force (MVF), the percentage contributions
of individual finger forces to the sum of individual finger
forces during four-finger MVF task (force sharing), and the nontask
finger forces during a task finger MVF task (force enslaving),
were computed as dependent variables. Force enslaving during finger
extension was greater than during flexion in both young and
elderly groups. The flexion–extension difference was greater in
the elderly than the young adult group. The greater independency
in flexion may result from more frequent use of finger flexion in
everyday manipulation tasks. The non-task fingers closer to a task
finger produced greater enslaving force than non-task fingers farther
from the task finger. The force sharing pattern was not different
between age groups. Our findings suggest that finger strength
decreases over the aging process, finger independency for flexion
increases throughout development, and force sharing pattern
remains constant across the lifespan.