The influence of lower leg configurations on muscle force variability

Edward Ofori, Jaeho Shim, Jacob J. Sosnoff

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The maintenance of steady contractions is required in many daily tasks. However, there is little understanding of how various lower limb configurations influence the ability to maintain force. The purpose of the current investigation was to examine the influence of joint angle on various lower-limb constant force contractions. Nineteen adults performed knee extension, knee flexion, and ankle plantarflexion isometric force contractions to 11 target forces, ranging from 2 to 95% maximal voluntary contraction (MVC) at 2 angles. Force variability was quantified with mean force, standard deviation, and the coefficient of variation of force output. Non-linearities in force output were quantified with approximate entropy. Curve fitting analyses were performed on each set of data from each individual across contractions to further examine whether joint angle interacts with global functions of lower-limb force variability. Joint angle had significant effects on the model parameters used to describe the force-variability function for each muscle contraction (p < 0.05). Regularities in force output were more explained by force level in smaller angle conditions relative to the larger angle conditions (p < 0.05). The findings support the notion that limb configuration influences the magnitude and regularities in force production. Biomechanical factors, such as joint angle, along with neurophysiological factors should be considered together in the discussion of the dynamics of constant force production.

Original languageEnglish (US)
Pages (from-to)111-118
Number of pages8
JournalJournal of Biomechanics
Volume71
DOIs
StatePublished - Apr 11 2018
Externally publishedYes

Fingerprint

Muscle
Leg
Joints
Lower Extremity
Muscles
Knee
Isometric Contraction
Entropy
Muscle Contraction
Ankle
Extremities
Maintenance
Curve fitting

Keywords

  • Approximate entropy
  • Force control
  • Joint position

ASJC Scopus subject areas

  • Biophysics
  • Orthopedics and Sports Medicine
  • Biomedical Engineering
  • Rehabilitation

Cite this

The influence of lower leg configurations on muscle force variability. / Ofori, Edward; Shim, Jaeho; Sosnoff, Jacob J.

In: Journal of Biomechanics, Vol. 71, 11.04.2018, p. 111-118.

Research output: Contribution to journalArticle

Ofori, Edward ; Shim, Jaeho ; Sosnoff, Jacob J. / The influence of lower leg configurations on muscle force variability. In: Journal of Biomechanics. 2018 ; Vol. 71. pp. 111-118.
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