title: Age-related differences in muscle co-activation during locomotion and their relationship with gait speed: a pilot study.
abstract: Muscle co-activation plays an important role in enhancing joint stability for movement regulation during motor learning activities. In normal aging, greater muscle co-activation is induced during gait in elderly adults. This study investigated age-related changes in muscle co-activation and spatio-temporal parameters during gait and identified the relationship between muscle co-activation and gait speed.
  
  
  
  A total of 46 adult volunteers participated in this study in three age groups (15 young adults [8 males, 7 females; age, 24.27 ± 2.71], 15 middle-aged adults [8 males, 7 females; age, 53.71 ± 2.52], and 16 elderly adults [7 males, 9 females; age, 76.88 ± 3.48]). All participants underwent locomotion analysis using a Three-dimensional motion analysis system and 12-channel dynamic electromyography.
  
  
  
  The elderly adults showed significantly higher co-activation than the young and middle-aged adults during gait (p < 0.05). In contrast, elderly adults showed significantly lower trunk co-activation than the young and middle-aged adults (p < 0.05). Muscle co-activation was significantly correlated with gait speed by aging. Muscle co-activation of the trunk showed a significant positive correlation with gait speed based on age. However, muscle co-activation of the lower extremity showed a significant negative correlation with gait speed based on age.
  
  
  
  This finding demonstrated that less muscle co-activation of the trunk was related to locomotive instability in elderly adults. Therefore, clarification of the relationship between trunk co-activation and locomotor instability will be helpful for developing optimal rehabilitation of elderly people to prevent fall.
authors.affiliation: Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Irwon-ro 81, Gangnam-gu, Seoul, 135-710, South Korea.
authors.forename: Hwang-Jae
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Irwon-ro 81, Gangnam-gu, Seoul, 135-710, South Korea.
authors.forename: Won Hyuk
authors.initials: WH
authors.lastname: Chang
authors.affiliation: Department of Neurology, Neuroscience Center, Samsung Medical Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Irwon-ro 81, Gangnam-gu, Seoul, 135-710, South Korea.
authors.forename: Byung-Ok
authors.initials: BO
authors.lastname: Choi
authors.affiliation: Office of Biomedical Science, Research Center for Future Medicine, Samsung Medical Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Irwon-ro 81, Gangnam-gu, Seoul, 135-710, Republic of Korea.
authors.forename: Gyu-Ha
authors.initials: GH
authors.lastname: Ryu
authors.affiliation: Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Irwon-ro 81, Gangnam-gu, Seoul, 135-710, South Korea. yunkim@skku.edu.
authors.forename: Yun-Hee
authors.initials: YH
authors.lastname: Kim
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D004576:Electromyography / Q000379:methods; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008124:Locomotion / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D010865:Pilot Projects; D060726:Torso / Q000502:physiology*; D000072797:Walking Speed / Q000502:physiology*; D055815:Young Adult
keywords: Aging; Co-activation; Electromyography; Gait speed; Locomotion; Stability