At the elite level, approximately 1 in 5 male soccer players suffer from a groin injury during each season and up to 40% experience an absence from the sport for more than 28 days (Harøy, 2019; Ishøi, 2016). Decreased hip adduction strength and a >20% deficit in eccentric strength of the hip adductors has been linked to an increase in risk of groin injury and pain (Harøy, 2019). Proper kicking mechanics utilize the hip adductors (primary groin muscles) in a lengthened state which increases their load under tension and vulnerability to injury.
About the Adductor Longus Muscle
The adductor longus muscle, is the biggest of the groin muscle group and most prone to injury in soccer. The Copenhagen Adductor exercise requires significant effort and training of the adductor longus muscle. This exercise has shown considerable changes in hip adduction eccentric strength, when following a standardized protocol (Ishøi, 2016). Kicking is the most frequent injury mechanism for acute groin injuries (Harøy, 2019). The groin muscles are used mostly during the swing phase of kicking and are at the greatest risk of injury when the athlete begins to bring the leg forward towards the ball (going from eccentric to concentric contraction) (Charnock, 2009). Groin muscles also require good strength and are at risk of injury during a 50/50 tackle against the opponent.
The Copenhagen Adductor exercise strengthens the adductors close to their position of vulnerability, is easily recreated by the athlete, and is minimally time-consuming. It is recommended to start an adductor training protocol prior to the training season if possible, and for best results should be continued throughout the competitive season. An 8-week supervised training program of the Copenhagen Adductor exercise demonstrated a 35.7% increase in hip adduction eccentric strength (Ishøi, 2016). Additionally, a 20% increase in hip abduction eccentric strength was shown following this same protocol which is an important component to decrease risk of knee injury in soccer players (Ishøi, 2016). Most notably, self-reported prevalence and risk of groin problems were reduced when a single adductor exercise with high compliance was completed as part of a preseason program (Harøy, 2019).
Performing the Copenhagen Adductor Exercise
Performing the Copenhagen Adductor exercise requires the support of a partner holding at the knee and the ankle while the athlete supports themselves on their elbow in a side plank position. The player then brings their bottom foot up to touch the top foot, and then return towards the ground in a controlled manner. Correct technique includes no side flexion of the upper body and maintaining a straight bottom leg. A high level of adductor strength is required with the Copenhagen Adductor exercise. While this specific exercise has been most researched, there are benefits to performing any hip adductor strength program.
Performance of a lower level adductor exercise initially may be appropriate for some athletes. If an exercise cannot be performed with correct technique, is painful during the exercise, or leaves an athlete with pain for 1-2 days afterwards then this exercise is too much. If the Copenhagen Adductor exercise is too difficult initially, consider performance of concentric hip adduction in side lying, or an isometric side plank hold (see photos below). Delayed onset muscle soreness (DOMS) can be expected after beginning a new strength program. This would leave an athlete with increased muscle soreness a few days after performance and is a normal response.
All of the above levels should follow the below progression, but modifications are recommended to make sure the dosage is appropriate for your athletes:
Week 1: 2 times a week 1 set of 3-5 per leg
Week 2: 3 times a week 1 set of 3-5 per leg
Week 3 & 4: 3 times a week 1 set of 7-10 per leg
Week 5 & 6: 3 times a week 1 set of 12-15 per leg
Week 7 & 8: 2 times a week 1 set of 12-15 per leg
During season: 1 time a week 1 set of 12-15 per leg
Meet Our Specialists:
Jon Ransom, PTA, ATC
Jon is a Physical Therapist Assistant and Certified Athletic Trainer for Therapeutic Associates Hillsboro. He has been the coordinator of Athletic Training services for FC Portland and their tournaments for 12 years. Jon has also taken dozens of FC Portland Academy athletes through Sportsmetrics training for ACL injury prevention.
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Rebe Colasurdo, PT, CMPT
Rebe is a Physical Therapist for Therapeutic Associates Hillsboro. She grew up in the Portland Metro area and played competitive soccer for FC Portland Academy. Rebe continued her soccer career for four years at Boise State University.
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Tim Brinker, PT, DPT, MBA, OCS, FAAOMT
Tim is the clinic director of Therapeutic Associates Hillsboro Physical Therapy. He is proud to have partnered and sponsored FC Portland since 2006 providing injury prevention, training and tournament coverage for the club.
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B. Charnock, C. Lewis, W. Garrett JR., R. Queen. Adductor longus mechanics during the maximal effort soccer kick, Sports Biomechanics. 2009;8(3):223-234
J. Harøy, D. Pope, B. Clarsen, E.G. Wiger, M.G. Øyen, A. Serner, K. Thorborg, P. Ho¨lmich, T.E. Andersen, R. Bahr . Infographic. The Adductor Strengthening Programme prevents groin problems among male football players. British Journal of Sports Medicine. 2019;53(1):45-46
L. Ishøi, C.N. Sørensen, N.M. Kaae, L.B. Jørgensen, P. Hölmich, A. Serner. Large eccentric strength increase using the Copenhagen Adduction exercise in football: A randomized controlled trial. Scandinavian Journal of Medicine & Science in Sports. 2016;26(11):1334-1342
J. Harøy, K. Thorborg, A. Serner, A. Bjørkheim, L. Rolstad, P. Hölmich, R. Bahr, T.E. Andersen. Including the copenhagen adduction exercise in the FIFA 11+ provides missing eccentric hip adduction strength effect in male soccer players: A randomized controlled trial. The American Journal of Sports Medicine. 2017;45(13):3052-59