title: Whole-body patterns of the range of joint motion in young adults: masculine type and feminine type.
abstract: BACKGROUND
  Understanding the whole-body patterns of joint flexibility and their related biological and physical factors contributes not only to clinical assessments but also to the fields of human factors and ergonomics. In this study, ranges of motion (ROMs) at limb and trunk joints of young adults were analysed to understand covariation patterns of different joint motions and to identify factors associated with the variation in ROM.
  
  
  METHODS
  Seventy-eight healthy volunteers (42 males and 36 females) living on Okinawa Island, Japan, were recruited. Passive ROM was measured at multiple joints through the whole body (31 measurements) including the left and right side limbs and trunk.
  
  
  RESULTS
  Comparisons between males and females, dominant and non-dominant sides, and antagonistic motions indicated that body structures influence ROMs. In principal component analysis (PCA) on the ROM data, the first principal component (PC1) represented the sex difference and a similar covariation pattern appeared in the analysis within each sex. Multiple regression analysis showed that this component was associated with sex, age, body fat %, iliospinale height, and leg extension strength.
  
  
  CONCLUSIONS
  The present study identified that there is a spectrum of "masculine" and "feminine" types in the whole-body patterns of joint flexibility. This study also suggested that body proportion and composition, muscle mass and strength, and possibly skeletal structures partly explain such patterns. These results would be important to understand individual variation in susceptibility to joint injuries and diseases and in one's suitable and effective postures and motions.
authors.affiliation: Department of Human Biology and Anatomy, Graduate School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 903-0215, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Moromizato
authors.affiliation: Department of Human Biology and Anatomy, Graduate School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 903-0215, Japan. rkimura@med.u-ryukyu.ac.jp.
authors.forename: Ryosuke
authors.identifier: http://orcid.org/0000-0003-0100-273X
authors.initials: R
authors.lastname: Kimura
authors.affiliation: Division of Human Evolution Studies, Graduate School of Medicine, Hokkaido University, Kita 15 Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Fukase
authors.affiliation: Department of Human Biology and Anatomy, Graduate School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 903-0215, Japan.|Present address: School of Natural Sciences and Psychology, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Yamaguchi
authors.affiliation: Department of Human Biology and Anatomy, Graduate School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 903-0215, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Ishida
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D008297:Male; D016059:Range of Motion, Articular / Q000502:physiology*; D012737:Sex Factors; D055815:Young Adult
keywords: Hand/foot dominance; Joints; Multiple regression analysis; Principal component analysis; Range of motion; Sexual dimorphism; Young adult