title: Large asymmetric hypertrophy of rectus abdominis muscle in professional tennis players.
abstract: OBJECTIVE
  To determine the volume and degree of asymmetry of the musculus rectus abdominis (RA) in professional tennis players.
  
  
  METHODS
  The volume of the RA was determined using magnetic resonance imaging (MRI) in 8 professional male tennis players and 6 non-active male control subjects.
  
  
  RESULTS
  Tennis players had 58% greater RA volume than controls (P = 0.01), due to hypertrophy of both the dominant (34% greater volume, P = 0.02) and non-dominant (82% greater volume, P = 0.01) sides, after accounting for age, the length of the RA muscle and body mass index (BMI) as covariates. In tennis players, there was a marked asymmetry in the development of the RA, which volume was 35% greater in the non-dominant compared to the dominant side (P<0.001). In contrast, no side-to-side difference in RA volume was observed in the controls (P = 0.75). The degree of side-to-side asymmetry increased linearly from the first lumbar disc to the pubic symphysis (r = 0.97, P<0.001).
  
  
  CONCLUSIONS
  Professional tennis is associated with marked hypertrophy of the musculus rectus abdominis, which achieves a volume that is 58% greater than in non-active controls. Rectus abdominis hypertrophy is more marked in the non-dominant than in the dominant side, particularly in the more distal regions. Our study supports the concept that humans can differentially recruit both rectus abdominis but also the upper and lower regions of each muscle. It remains to be determined if this disequilibrium raises the risk of injury.
authors.affiliation: Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain. jsanchis@def.ulpgc.es
authors.forename: Joaquin
authors.initials: J
authors.lastname: Sanchis-Moysi
authors.forename: Fernando
authors.initials: F
authors.lastname: Idoate
authors.forename: Cecilia
authors.initials: C
authors.lastname: Dorado
authors.forename: Santiago
authors.initials: S
authors.lastname: Alayón
authors.forename: Jose A L
authors.initials: JA
authors.lastname: Calbet
mesh_terms: D000328:Adult; D056352:Athletes; D001823:Body Composition; D015992:Body Mass Index; D016022:Case-Control Studies; D006801:Humans; D006984:Hypertrophy / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D017568:Rectus Abdominis / Q000033:anatomy & histology* / Q000503:physiopathology; D013715:Tennis