title: Coactivation of lower leg muscles during body weight-supported treadmill walking decreases with age in adolescents.
abstract: The kinematics of children's walking are nearly adult-like by about age 3-4 years, but metabolic efficiency of walking does not reach adult values until late in adolescence or early adulthood, perhaps due to higher coactivation of agonist/antagonist muscle pairs in adolescents. Additionally, it is unknown how use of a body weight-supported treadmill device affects coactivation, but because unloading will alter the activity of anti-gravity muscles, it was hypothesized that muscle coactivation will be altered as well. Muscle coactivation during treadmill walking was evaluated for adolescents (ages 10 to 17 years, M = 13.2, SD = 2.2) and adults (ages 22 to 35 years, M = 25.2, SD = 4.3), for thigh muscles (vastus lateralis/biceps femoris) and lower leg muscles (tibialis anterior/gastrocnemius). Conditions included body weight unloadings from nearly 0% to 80% of body weight, while walking at a preferred speed (self-selected, overground speed) or a reduced speed. Unloading was accomplished using a lower body positive pressure support system. Coactivation was found to be higher in adolescents than in adults, but only for the lower leg muscles.
authors.affiliation: Munroe-Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, USA.
authors.forename: Joan E
authors.initials: JE
authors.lastname: Deffeyes
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Karst
authors.forename: Wayne A
authors.initials: WA
authors.lastname: Stuberg
authors.forename: Max J
authors.initials: MJ
authors.lastname: Kurz
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001835:Body Weight / Q000502:physiology; D002648:Child; D004576:Electromyography; D005080:Exercise Test / Q000379:methods*; D006801:Humans; D007866:Leg / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D013848:Thigh / Q000502:physiology*; D016138:Walking / Q000502:physiology*; D055815:Young Adult