title: Force Irregularity Following Maximal Effort: The After-Peak Reduction.
abstract: Irregularities in force output are present throughout human movement and can impair task performance. We investigated the presence of a large force discontinuity (after-peak reduction, APR) that appeared immediately following peak in maximal effort ramp contractions performed with the thumb adductor and ankle dorsiflexor muscles in 25 young adult participants (76% males, 24% females; M age 24.4 years, SD = 7.1). The after-peak reduction displayed similar parameters in both muscle groups with comparable drops in force during the after-peak reduction minima (thumb adductor: 27.5 ± 7.5% maximal voluntary contraction; ankle dorsiflexor: 25.8 ± 6.2% maximal voluntary contraction). A trend for the presence of fewer after-peak reductions with successive ramp trials was observed, suggesting a learning effect. Further investigation should explore underlying neural mechanisms contributing to the after-peak reduction.
authors: Department of Occupational Therapy, Louisiana State University Health Sciences Center, New Orleans, LA, USA bdouc3@lsuhsc.edu.
authors: Barbara M
authors: BM
authors: Doucet
authors: Department of Health and Human Performance, Texas State University, San Marcos, TX, USA.
authors: Joni A
authors: JA
authors: Mettler
authors: Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, USA.
authors: Lisa
authors: L
authors: Griffin
authors: Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, USA.
authors: Waneen
authors: W
authors: Spirduso
mesh_terms: D000328:Adult; D000842:Ankle / Q000502:physiology*; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009048:Motor Skills / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D013933:Thumb / Q000502:physiology*; D055815:Young Adult
keywords: fine motor coordination; force output; force variability; gross motor coordination; motor control