title: Large eccentric strength increase using the Copenhagen Adduction exercise in football: A randomized controlled trial.
abstract: Hip adductor injuries are frequent in football, and players with low adductor strength appear to be at increased risk of injury. High adductor muscle activity has been shown in the Copenhagen Adduction exercise (CA); however, an associated strength gain has not been investigated. This study aims to examine the eccentric hip adduction strength (EHAD) gain using the CA in-season. Two U-19 sub-elite football teams, including 24 football players, were randomized to either an 8-week supervised progressive training program in addition to the usual training (intervention) or to continue training as usual (control). EHAD, eccentric hip abduction strength (EHAB), and side-bridge endurance were measured using reliable test procedures at baseline and follow-up by a blinded tester. There was a significant interaction between group and time on EHAD, EHAB, and EHAD/EHAB ratio (P < 0.025). The intervention group demonstrated a 35.7% increase in EHAD (P < 0.001); a 20.3% increase in EHAB (P = 0.003), and 12.3% increase in EHAD/EHAB ratio (P = 0.019). No significant within-group differences were found in the control group (P > 0.335). Compliance was 91.25%, and median muscle soreness ranged from 0 to 2. The CA implemented in-season with an 8-week progressive training program elicited a large significant increase in EHAD, EHAB, and EHAD/EHAB ratio.
authors.affiliation: Department of Physiotherapy, Metropolitan University College, Copenhagen, Denmark. lasse.ishoei@gmail.com.
authors.forename: L
authors.initials: L
authors.lastname: Ishøi
authors.affiliation: Department of Physiotherapy, Metropolitan University College, Copenhagen, Denmark.
authors.forename: C N
authors.initials: CN
authors.lastname: Sørensen
authors.affiliation: Department of Physiotherapy, Metropolitan University College, Copenhagen, Denmark.
authors.forename: N M
authors.initials: NM
authors.lastname: Kaae
authors.affiliation: Muskuloskeletal Rehabilitation Research Unit, Department of Physical and Occupational Therapy, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Copenhagen, Denmark.
authors.forename: L B
authors.initials: LB
authors.lastname: Jørgensen
authors.affiliation: Sports Groin Pain Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.|Sports Orthopedic Research Center - Copenhagen (SORC-C), Arthroscopic Center, Department of Orthopedic Surgery, Copenhagen University Hospital, Amager & Hvidovre, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Hölmich
authors.affiliation: Sports Groin Pain Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.|Sports Orthopedic Research Center - Copenhagen (SORC-C), Arthroscopic Center, Department of Orthopedic Surgery, Copenhagen University Hospital, Amager & Hvidovre, Denmark.
authors.forename: A
authors.initials: A
authors.lastname: Serner
mesh_terms: D000293:Adolescent; D056352:Athletes; D001265:Athletic Injuries; D003718:Denmark; D006615:Hip; D025981:Hip Injuries; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D053580:Muscle Strength; D018482:Muscle, Skeletal; D055070:Resistance Training / Q000379:methods*; D016037:Single-Blind Method; D012916:Soccer; D055815:Young Adult
keywords: Resistance training; groin injuries; hip adductors; prevention