title: Upper Limb Strength and Muscle Volume in Healthy Middle-Aged Adults.
abstract: Our purpose was to characterize shoulder muscle volume and isometric moment, as well as their relationship, for healthy middle- aged adults. Muscle volume and maximum isometric joint moment were assessed for 6 functional muscle groups of the shoulder, elbow, and wrist in 10 middle-aged adults (46&ndash;60 y, 5M, 5F). Compared with young adults, shoulder abductors composed a smaller percentage of total muscle volume (P = .0009) and there was a reduction in shoulder adductor strength relative to elbow flexors (P = .012). We observed a consistent ordering of moment-generating capacity among functional groups across subjects. Although total muscle volume spanned a 2.3-fold range, muscle volume was distributed among functional groups in a consistent manner across subjects. On average, 72% of the variation in joint moment could be explained by the corresponding functional group muscle volume. These data are useful for improved modeling of upper limb musculoskeletal performance in middle-aged subjects, and may improve computational predictions of function for this group.
authors.affiliation: Mechanical and Aerospace Engineering Department, North Carolina State University, Raleigh, NC.
authors.forename: Katherine R
authors.initials: KR
authors.lastname: Saul
authors.forename: Meghan E
authors.initials: ME
authors.lastname: Vidt
authors.forename: Garry E
authors.initials: GE
authors.lastname: Gold
authors.forename: Wendy M
authors.initials: WM
authors.lastname: Murray
mesh_terms: D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D009929:Organ Size / Q000502:physiology; D004856:Postural Balance / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D034941:Upper Extremity / Q000502:physiology*