Quadriceps muscle volume positively contributes to ACL volume

Area of Science:

• Orthopedics
• Sports Medicine
• Anatomy

Background:

• Females exhibit smaller anterior cruciate ligaments (ACLs) compared to males, correlating with higher ACL injury rates.
• Overall body dimensions do not fully account for these sex-based differences in ACL size.

Purpose of the Study:

• To investigate the predictive relationship between quadriceps muscle volume (VOL_QUAD) and ACL volume (VOL_ACL).
• To determine if VOL_QUAD predicts VOL_ACL independently of sex and other anthropometric measures.

Main Methods:

• Magnetic resonance imaging (MRI) was used to measure VOL_ACL, VOL_QUAD, hamstring muscle volume, and femoral notch dimensions in 20 physically active individuals (10 males, 10 females).
• Three-step regression analyses were performed to assess the association between VOL_QUAD and VOL_ACL, controlling for sex and body dimensions (height, BMI, hamstring volume, notch width/index).

Main Results:

• Quadriceps muscle volume (VOL_QUAD) consistently and positively predicted ACL volume (VOL_ACL) across dominant, nondominant, and averaged legs (p < 0.05).
• This association remained significant even after controlling for sex, BMI, hamstring volume, and notch width index.
• Once VOL_QUAD was accounted for, only notch width and notch width index retained significant individual associations with VOL_ACL (p < 0.01).

Conclusions:

• Quadriceps muscle volume is a significant positive predictor of ACL volume, independent of sex and other anthropometric factors.
• The findings suggest that ACL size may be partially modifiable.
• Further research is warranted to explore the potential of targeted training programs to enhance ACL size and structure, particularly in young females.