title: Comparison of timing and force control of foot tapping between elderly and young subjects.
abstract: [Purpose] To examine the ability of young and elderly individuals to control the timing and force of periodic sequential foot tapping. [Subjects and Methods] Participants were 10 young (age, 22.1 ± 4.3 years) and 10 elderly individuals (74.8 ± 6.7 years) who were healthy and active. The foot tapping task consisted of practice (stimulus-synchronized tapping with visual feedback) and recall trials (self-paced tapping without visual feedback), periodically performed in this order, at 500-, 1,000-, and 2,000-ms target interstimulus-onset intervals, with a target force of 20% maximum voluntary contraction of the ankle plantar-flexor muscle. [Results] The coefficients of variation of force and intertap interval, used for quantifying the steadiness of the trials, were significantly greater in the elderly than in the young individuals. At the 500-ms interstimulus-onset interval, age-related effects were observed on the normalized mean absolute error of force, which was used to quantify the accuracy of the trials. The coefficients of variation of intertap interval for elderly individuals were significantly greater in the practice than in the recall trials at the 500- and 1,000-ms interstimulus-onset intervals. [Conclusion] The elderly individuals exhibited greater force and timing variability than the young individuals and showed impaired visuomotor processing during foot tapping sequences.
authors.affiliation: Department of Physical Therapy, Tosa Rehabilitation College, Japan; Department of Physiology, Kochi Medical School, Kochi University, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Takimoto
authors.affiliation: Department of Physical Therapy, Tosa Rehabilitation College, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takebayashi
authors.affiliation: Department of Physical Therapy, Tosa Rehabilitation College, Japan.
authors.forename: Kenzo
authors.initials: K
authors.lastname: Miyamoto
authors.affiliation: Department of Physical Therapy, Tosa Rehabilitation College, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takuma
authors.affiliation: Department of Physical Therapy, Tosa Rehabilitation College, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Inoue
authors.affiliation: Department of Physical Therapy, Tosa Rehabilitation College, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Miyamoto
authors.affiliation: Department of Physical Therapy, Tosa Rehabilitation College, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Okabe
authors.affiliation: Department of Physical Therapy, Tosa Rehabilitation College, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Okuda
authors.affiliation: Department of Physiology, Kochi Medical School, Kochi University, Japan.
authors.forename: Hideto
authors.initials: H
authors.lastname: Kaba
keywords: Aging; Foot tapping; Timing and force control