The relationship of hamstrings and quadriceps strength to anterior cruciate ligament injury in female athletes

Gregory D. Myer, Kevin R. Ford, Kim D. Barber Foss, Chunyan Liu, Todd G. Nick, Timothy E. Hewett

Research output: Contribution to journalArticlepeer-review

220 Scopus citations


OBJECTIVE : To determine the association of quadriceps and hamstrings strength to anterior cruciate ligament (ACL) injury risk in female athletes. The primary hypothesis was that there would be decreased knee flexor and increased knee extensor strength in female athletes who went on to ACL injured status (FACL) compared to uninjured female (FC) and male (MC) control subjects. Study design: Matched case control. Setting: Institutional Biomechanics Laboratory. Participants: Prospectively measured FACL (n = 22) female athletes who subsequently suffered confirmed noncontact ACL ruptures (16 during soccer and 6 during basketball play) were matched (1:4 ratio) to female controls (FC; n = 88) using limb (dominant or nondominant), pubertal status, sport, and nearest height and mass. In addition, male controls (MC) were matched (1:1 ratio) to FACL to serve as a secondary comparative control. ASSESSMENT OF RISK FACTORS: Isokinetic (concentric) knee extension/flexion strength (300 degrees/s). Results: FACL subjects had decreased hamstrings strength compared to MC (15%; 95% CI, 1 to 27%; P = 0.04). FC were not different from MC in hamstrings strength. Conversely, FACL subjects did not differ compared to the MC in quadriceps strength, and the FC demonstrated decreased quadriceps strength relative to MC (10%; 95% CI, 3 to 18%; P = 0.01). Conclusions: The results of this investigation indicate that female athletes who suffered ACL injury subsequent to strength testing had a combination of decreased hamstrings strength but not quadriceps strength compared to males. In direct contrast, female athletes who did not go on to ACL injury had decreased quadriceps strength and similar hamstrings strength compared to matched male athletes.

Original languageEnglish (US)
Pages (from-to)3-8
Number of pages6
JournalClinical Journal of Sport Medicine
Issue number1
StatePublished - Jan 2009


  • Anterior cruciate ligament injury prediction
  • Isokinetic outcome measure
  • Knee co-contraction
  • Knee flexor to extensor ratio
  • Knee torques

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation


Dive into the research topics of 'The relationship of hamstrings and quadriceps strength to anterior cruciate ligament injury in female athletes'. Together they form a unique fingerprint.

Cite this