Knee Surgery, Sports Traumatology, Arthroscopy

, Volume 26, Issue 4, pp 1137–1144 | Cite as

Hip external rotation strength predicts hop performance after anterior cruciate ligament reconstruction

  • Paul W. Kline
  • Jeremy Burnham
  • Michael Yonz
  • Darren Johnson
  • Mary Lloyd Ireland
  • Brian NoehrenEmail author



Quadriceps strength and single-leg hop performance are commonly evaluated prior to return to sport after anterior cruciate ligament reconstruction (ACLR). However, few studies have documented potential hip strength deficits after ACLR, or ascertained the relative contribution of quadriceps and hip strength to hop performance.


Patients cleared for return to sports drills after ACLR were compared to a control group. Participants’ peak isometric knee extension, hip abduction, hip extension, and hip external rotation (HER) strength were measured. Participants also performed single-leg hops, timed hops, triple hops, and crossover hops. Between-limb comparisons for the ACLR to control limb and the non-operative limb were made using independent two-sample and paired sample t tests. Pearson’s correlations and stepwise multiple linear regression were used to determine the relationships and predictive ability of limb strength, graft type, sex, and limb dominance to hop performance.


Sixty-five subjects, 20 ACLR [11F, age 22.8 (15–45) years, 8.3 ± 2 months post-op, mass 70.47 ± 12.95 kg, height 1.71 ± 0.08 m, Tegner 5.5 (3–9)] and 45 controls [22F, age 25.8 (15–45) years, mass 74.0 ± 15.2 kg, height 1.74 ± 0.1 m, Tegner 6 (3–7)], were tested. Knee extension (4.4 ± 1.5 vs 5.4 ± 1.8 N/kg, p = 0.02), HER (1.4 ± 0.4 vs 1.7 ± 0.5 N/kg, p = 0.04), single-leg hop (146 ± 37 vs 182 ± 38% limb length, p < 0.01), triple hop (417 ± 106 vs 519 ± 102% limb length, p < 0.01), timed hop (3.3 ± 2.0 vs 2.3 ± 0.6 s, p < 0.01), and crossover hop (364 ± 107 vs 446 ± 123% limb length, p = 0.01) were significantly impaired in the operative versus control subject limbs. Similar deficits existed between the operative and non-operative limbs. Knee extension and HER strength were significantly correlated with each of the hop tests, but only HER significantly predicted hop performance.


After ACLR, patients have persistent HER strength, knee extension strength, and hop test deficits in the operative limb compared to the control and non-operative limbs, even after starting sport-specific drills. Importantly, HER strength independently predicted hop performance. Based on these findings, to resolve between-limb deficits in strength and hop performance clinicians should include HER strengthening exercises in post-operative rehabilitation.

Level of evidence

Prognostic Study, Level II.


ACL Hip strength Rehabilitation Quadriceps 



Anterior cruciate ligament reconstruction


Hip external rotation


Return to sport


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


This study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health (grant number K23AR062069) and by the National Center for Advancing Translational Sciences of the National Institutes of Health (grant number TL1TR00015).

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.


  1. 1.
    Anderson MJ, Browning WM 3rd, Urband CE, Kluczynski MA, Bisson LJ (2016) A systematic summary of systematic reviews on the topic of the anterior cruciate ligament. Orthop J Sports Med 4(3):2325967116634074CrossRefPubMedPubMedCentralGoogle Scholar
  2. 2.
    Buller LT, Best MJ, Baraga MG, Kaplan LD (2015) Trends in anterior cruciate ligament reconstruction in the united states. Orthop J Sports Med 3(1):2325967114563664CrossRefPubMedGoogle Scholar
  3. 3.
    Burnham JM, Yonz MC, Robertson KE, McKinley R, Wilson BR, Johnson DL, Ireland ML, Noehren B (2016) Relationship of hip and trunk muscle function with single leg step-down performance: implications for return to play screening and rehabilitation. Phys Ther Sport 22:66–73CrossRefPubMedGoogle Scholar
  4. 4.
    Comyns T, Kenny I, Scales G (2015) Effects of a low-load gluteal warm-up on explosive jump performance. J Hum Kinet 46:177–187CrossRefPubMedPubMedCentralGoogle Scholar
  5. 5.
    Dalton EC, Pfile KR, Weniger GR, Ingersoll CD, Herman D, Hart JM (2011) Neuromuscular changes after aerobic exercise in people with anterior cruciate ligament-reconstructed knees. J Athl Train 46(5):476–483CrossRefPubMedPubMedCentralGoogle Scholar
  6. 6.
    Di Stasi S, Myer GD, Hewett TE (2013) Neuromuscular training to target deficits associated with second anterior cruciate ligament injury. J Orthop Sports Phys Ther 43(11):777–792 (A771–711) CrossRefPubMedPubMedCentralGoogle Scholar
  7. 7.
    Frank B, Bell DR, Norcross MF, Blackburn JT, Goerger BM, Padua DA (2013) Trunk and hip biomechanics influence anterior cruciate loading mechanisms in physically active participants. Am J Sports Med 41(11):2676–2683CrossRefPubMedGoogle Scholar
  8. 8.
    Garrison JC, Bothwell J, Cohen K, Conway J (2014) Effects of hip strengthening on early outcomes following anterior cruciate ligament reconstruction. Int J Sports Phys Ther 9(2):157–167PubMedPubMedCentralGoogle Scholar
  9. 9.
    Grindem H, Snyder-Mackler L, Moksnes H, Engebretsen L, Risberg MA (2016) Simple decision rules can reduce reinjury risk by 84% after acl reconstruction: the delaware-oslo acl cohort study. Br J Sports Med 50(13):804–808CrossRefPubMedPubMedCentralGoogle Scholar
  10. 10.
    Hegedus EJ, McDonough S, Bleakley C, Cook CE, Baxter GD (2015) Clinician-friendly lower extremity physical performance measures in athletes: a systematic review of measurement properties and correlation with injury, part 1. The tests for knee function including the hop tests. Br J Sports Med 49(10):642–648CrossRefPubMedGoogle Scholar
  11. 11.
    Hewett TE, Di Stasi SL, Myer GD (2013) Current concepts for injury prevention in athletes after anterior cruciate ligament reconstruction. Am J Sports Med 41(1):216–224CrossRefPubMedGoogle Scholar
  12. 12.
    Hollman JH, Ginos BE, Kozuchowski J, Vaughn AS, Drause DA, Youdas JW (2009) Relationships between knee valgus, hip-muscle recruitment during a single-limb step-down. J Sport Rehabil 18(1):104–117CrossRefPubMedGoogle Scholar
  13. 13.
    Jacobs CA, Uhl TL, Mattacola CG, Shapiro R, Rayens WS (2007) Hip abductor function and lower extremity landing kinematics: sex differences. J Athl Train 42(1):76–83PubMedPubMedCentralGoogle Scholar
  14. 14.
    Karanikas K, Arampatzis A, Bruggemann GP (2009) Motor task and muscle strength followed different adaptation patterns after anterior cruciate ligament reconstruction. Eur J Phys Rehabil Med 45(1):37–45PubMedGoogle Scholar
  15. 15.
    Khayambashi K, Ghoddosi N, Straub RK, Powers CM (2016) Hip muscle strength predicts noncontact anterior cruciate ligament injury in male and female athletes: a prospective study. Am J Sports Med 44(2):355–361CrossRefPubMedGoogle Scholar
  16. 16.
    Kline PW, Johnson DL, Ireland ML, Noehren B (2016) Clinical predictors of knee mechanics at return to sport after acl reconstruction. Med Sci Sports Exerc 48(5):790–795CrossRefPubMedPubMedCentralGoogle Scholar
  17. 17.
    Kockum B, Heijne AI (2015) Hop performance and leg muscle power in athletes: reliability of a test battery. Phys Ther Sport 16(3):222–227CrossRefPubMedGoogle Scholar
  18. 18.
    Kyritsis P, Bahr R, Landreau P, Miladi R, Witvrouw E (2016) Likelihood of acl graft rupture: not meeting six clinical discharge criteria before return to sport is associated with a four times greater risk of rupture. Br J Sports Med 50(15):946–951CrossRefPubMedGoogle Scholar
  19. 19.
    Lepley LK (2015) Deficits in quadriceps strength and patient-oriented outcomes at return to activity after acl reconstruction: a review of the current literature. Sports Health 7(3):231–238CrossRefPubMedPubMedCentralGoogle Scholar
  20. 20.
    Lieberman DE, Raichlen DA, Pontzer H, Bramble DM, Cutright-Smith E (2006) The human gluteus maximus and its role in running. J Exp Biol 209(Pt 11):2143–2155CrossRefPubMedGoogle Scholar
  21. 21.
    Logerstedt D, Grindem H, Lynch A, Eitzen I, Engebretsen L, Risberg MA, Axe MJ, Snyder-Mackler L (2012) Single-legged hop tests as predictors of self-reported knee function after anterior cruciate ligament reconstruction: the delaware-oslo acl cohort study. Am J Sports Med 40(10):2348–2356CrossRefPubMedPubMedCentralGoogle Scholar
  22. 22.
    Makhni EC, Crump EK, Steinhaus ME, Verma NN, Ahmad CS, Cole BJ, Bach BR Jr (2016) Quality and variability of online available physical therapy protocols from academic orthopaedic surgery programs for anterior cruciate ligament reconstruction. Arthroscopy 32(8):1612–1621CrossRefPubMedGoogle Scholar
  23. 23.
    Mall NA, Chalmers PN, Moric M, Tanaka MJ, Cole BJ, Bach BR Jr, Paletta GA Jr (2014) Incidence and trends of anterior cruciate ligament reconstruction in the united states. Am J Sports Med 42(10):2363–2370CrossRefPubMedGoogle Scholar
  24. 24.
    Mueller LM, Bloomer BA, Durall CJ (2014) Which outcome measures should be utilized to determine readiness to play after acl reconstruction? J Sport Rehabil 23(2):158–164CrossRefPubMedGoogle Scholar
  25. 25.
    Munro AG, Herrington LC (2011) Between-session reliability of four hop tests and the agility t test. J Strength Cond Res 25(5):1470–1477CrossRefPubMedGoogle Scholar
  26. 26.
    Myer GD, Schmitt LC, Brent JL, Ford KR, Barber Foss KD, Scherer BJ, Heidt RS Jr, Divine JG, Hewett TE (2011) Utilization of modified nfl combine testing to identify functional deficits in athletes following acl reconstruction. J Orthop Sports Phys Ther 41(6):377–387CrossRefPubMedPubMedCentralGoogle Scholar
  27. 27.
    Neumann DA (2010) Kinesiology of the hip: a focus on muscular actions. J Orthop Sports Phys Ther 40(2):82–94CrossRefPubMedGoogle Scholar
  28. 28.
    Noehren B, Abraham A, Curry M, Johnson D, Ireland ML (2014) Evaluation of proximal joint kinematics and muscle strength following ACL reconstruction surgery in female athletes. J Orthop Res 32(10):1305–1310CrossRefPubMedPubMedCentralGoogle Scholar
  29. 29.
    Norris B, Trudelle-Jackson E (2011) Hip- and thigh-muscle activation during the star excursion balance test. J Sport Rehabil 20(4):428–441CrossRefPubMedGoogle Scholar
  30. 30.
    Pairot de Fontenay B, Argaud S, Blache Y, Monteil K (2015) Contralateral limb deficit seven months after acl-reconstruction: an analysis of single-leg hop tests. Knee 22(4):309–312CrossRefPubMedGoogle Scholar
  31. 31.
    Palmieri-Smith RM, Lepley LK (2015) Quadriceps strength asymmetry after anterior cruciate ligament reconstruction alters knee joint biomechanics and functional performance at time of return to activity. Am J Sports Med 43(7):1662–1669CrossRefPubMedPubMedCentralGoogle Scholar
  32. 32.
    Paterno MV, Schmitt LC, Ford KR, Rauh MJ, Myer GD, Huang B, Hewett TE (2010) Biomechanical measures during landing and postural stability predict second anterior cruciate ligament injury after anterior cruciate ligament reconstruction and return to sport. Am J Sports Med 38(10):1968–1978CrossRefPubMedPubMedCentralGoogle Scholar
  33. 33.
    Petersen W, Taheri P, Forkel P, Zantop T (2014) Return to play following acl reconstruction: a systematic review about strength deficits. Arch Orthop Trauma Surg 134(10):1417–1428CrossRefPubMedGoogle Scholar
  34. 34.
    Pietrosimone BG, Lepley AS, Ericksen HM, Gribble PA, Levine J (2013) Quadriceps strength and corticospinal excitability as predictors of disability after anterior cruciate ligament reconstruction. J Sport Rehabil 22(1):1–6CrossRefPubMedGoogle Scholar
  35. 35.
    Reid A, Birmingham TB, Stratford PW, Alcock GK, Giffin JR (2007) Hop testing provides a reliable and valid outcome measure during rehabilitation after anterior cruciate ligament reconstruction. Phys Ther 87(3):337–349CrossRefPubMedGoogle Scholar
  36. 36.
    Reinke EK, Spindler KP, Lorring D, Jones MH, Schmitz L, Flanigan DC, An AQ, Quiram AR, Preston E, Martin M, Schroeder B, Parker RD, Kaeding CC, Borzi L, Pedroza A, Huston LJ, Harrell FE Jr, Dunn WR (2011) Hop tests correlate with ikdc and koos at minimum of 2 years after primary acl reconstruction. Knee Surg Sports Traumatol Arthrosc 19(11):1806–1816CrossRefPubMedPubMedCentralGoogle Scholar
  37. 37.
    Ross MD, Irrgang JJ, Denegar CR, McCloy CM, Unangst ET (2002) The relationship between participation restrictions and selected clinical measures following anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc 10(1):10–19CrossRefPubMedGoogle Scholar
  38. 38.
    Schmitt LC, Paterno MV, Hewett TE (2012) The impact of quadriceps femoris strength asymmetry on functional performance at return to sport following anterior cruciate ligament reconstruction. J Orthop Sports Phys Ther 42(9):750–759CrossRefPubMedPubMedCentralGoogle Scholar
  39. 39.
    Stickler L, Finley M, Gulgin H (2015) Relationship between hip and core strength and frontal plane alignment during a single leg squat. Phys Ther Sport 16(1):66–71CrossRefPubMedGoogle Scholar
  40. 40.
    Svensson M, Sernert N, Ejerhed L, Karlsson J, Kartus JT (2006) A prospective comparison of bone-patellar tendon-bone and hamstring grafts for anterior cruciate ligament reconstruction in female patients. Knee Surg Sports Traumatol Arthrosc 14(3):278–286CrossRefPubMedGoogle Scholar
  41. 41.
    Thorborg K, Bandholm T, Holmich P (2013) Hip- and knee-strength assessments using a hand-held dynamometer with external belt-fixation are inter-tester reliable. Knee Surg Sports Traumatol Arthrosc 21(3):550–555CrossRefPubMedGoogle Scholar
  42. 42.
    Wiggins AJ, Grandhi RK, Schneider DK, Stanfield D, Webster KE, Myer GD (2016) Risk of secondary injury in younger athletes after anterior cruciate ligament reconstruction: a systematic review and meta-analysis. Am J Sports Med 44(7):1861–1876CrossRefPubMedPubMedCentralGoogle Scholar

Copyright information

© European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2017

Authors and Affiliations

  1. 1.Department of Rehabilitation SciencesUniversity of KentuckyLexingtonUSA
  2. 2.Center for Sports MedicineUniversity of Pittsburgh Medical CenterPittsburghUSA
  3. 3.Department of Orthopedic Surgery and Sports MedicineUniversity of KentuckyLexingtonUSA
  4. 4.Division of Physical TherapyUniversity of KentuckyLexingtonUSA

Personalised recommendations