title: Eccentric and Isometric Hip Adduction Strength in Male Soccer Players With and Without Adductor-Related Groin Pain: An Assessor-Blinded Comparison.
abstract: BACKGROUND
  Adductor-related pain is the most common clinical finding in soccer players with groin pain and can be a long-standing problem affecting physical function and performance. Hip adductor weakness has been suggested to be associated with this clinical entity, although it has never been investigated.
  
  
  OBJECTIVE
  To investigate whether isometric and eccentric hip strength are decreased in soccer players with adductor-related groin pain compared with asymptomatic soccer controls. The hypothesis was that players with adductor-related groin pain would have lower isometric and eccentric hip adduction strength than players without adductor-related groin pain.
  
  
  METHODS
  Cross-sectional study; Level of evidence, 3.
  
  
  METHODS
  Male elite and subelite players from 40 teams were contacted. In total, 28 soccer players with adductor-related groin pain and 16 soccer players without adductor-related groin pain (asymptomatic controls) were included in the study. In primary analysis, the dominant legs of 21 soccer players with adductor-related groin pain (≥4 weeks duration) were compared with the dominant legs of 16 asymptomatic controls using a cross-sectional design. The mean age of the symptomatic players was 24.5 ± 2.5 years, and the mean age of the asymptomatic controls was 22.9 ± 2.4 years. Isometric hip strength (adduction, abduction, and flexion) and eccentric hip strength (adduction) were assessed with a handheld dynamometer using reliable test procedures and a blinded assessor.
  
  
  RESULTS
  Eccentric hip adduction strength was lower in soccer players with adductor-related groin pain in the dominant leg (n = 21) compared with asymptomatic controls (n = 16), namely 2.47 ± 0.49 versus 3.12 ± 0.43 N·m/kg, respectively (P < .001). No other hip strength differences were observed between symptomatic players and asymptomatic controls for the dominant leg (P = .35-.84).
  
  
  CONCLUSIONS
  Large eccentric hip adduction strength deficits were found in soccer players with adductor-related groin pain compared with asymptomatic soccer players, while no isometric strength differences were observed between the groups.
authors.affiliation: Sports Orthopaedic Research Center, Arthroscopic Centre Amager, Copenhagen University Hospital, Amager-Hvidovre, Denmark. ; Physical Medicine & Rehabilitation Research-Copenhagen (PMR-C) and Departments of Orthopaedic Surgery and Physical Therapy, Copenhagen University Hospital, Amager-Hvidovre, Denmark.
authors.forename: Kristian
authors.initials: K
authors.lastname: Thorborg
authors.affiliation: Sports Orthopaedic Research Center, Arthroscopic Centre Amager, Copenhagen University Hospital, Amager-Hvidovre, Denmark. ; Department of Radiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Sonia
authors.initials: S
authors.lastname: Branci
authors.affiliation: Sports Orthopaedic Research Center, Arthroscopic Centre Amager, Copenhagen University Hospital, Amager-Hvidovre, Denmark.
authors.forename: Martin Peter
authors.initials: MP
authors.lastname: Nielsen
authors.affiliation: Sports Orthopaedic Research Center, Arthroscopic Centre Amager, Copenhagen University Hospital, Amager-Hvidovre, Denmark. ; Physical Medicine & Rehabilitation Research-Copenhagen (PMR-C) and Departments of Orthopaedic Surgery and Physical Therapy, Copenhagen University Hospital, Amager-Hvidovre, Denmark.
authors.forename: Lars
authors.initials: L
authors.lastname: Tang
authors.affiliation: Department of Radiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Michael Bachmann
authors.initials: MB
authors.lastname: Nielsen
authors.affiliation: Sports Orthopaedic Research Center, Arthroscopic Centre Amager, Copenhagen University Hospital, Amager-Hvidovre, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Hölmich
keywords: adductor muscles; eccentric strength; groin injury; hip adduction/abduction ratio; hip strength; male soccer