WHY
FEMALE ATHLETES MAY BE AT GREATER RISK FOR ACL INJURY
Steve Daisey MPT, CSCS
| A
growing approach to ACL injury prevention involves training
of the hip muscles. This originated from the frequent clinical
observation that female athletes tend to place greater stress
on their knees. This can be seen visually and often felt
by the athlete (with pain around the knee itself during
a squat). This study lends some support to this theory.
Performing a single leg squat is a quick,
but often effective way to identify athletes who may be
at a greater risk than others. Have your athletes perform
a squat standing on one leg without holding on to anything
for support.
Look
for the following:
- Loss of control or an inability to get the
knee to about a 90 degree angle
- The knee drifting far in front of the toes
- Pain in the knee
- The knee turns inward (look at the kneecap
for this)
If you
observe any of the above, the athlete may be at a greater
risk for a knee injury.
There are simple exercises which can be performed to help
correct these muscle activation patterns.
Contact Daisey Physical Therapy and the Center for Human
Performance at 757-854-0500 for more information on ACL
injury prevention training.
|
A study (4)
in the American Journal of Sports Medicine showed that male and
female athletes activate their leg muscles differently, which could
increase the likelihood of knee injury in females. Specifically,
the study suggests that female athletes have more difficulty controlling
their hip muscles, which in turn places stress on the knee.
Participants were asked to perform a single leg squat.
Muscle activation patterns and joint positions during the squat
were measured.
The following was found:
- The knee of the squat leg turned inward (valgus movement) much
more with the female athletes because the femur moved inward (hip
adduction).
- The gluteal
muscles (gluteus medius) were much less active (47% less) in females.
This would contribute greatly to the inward motion of the femur
and knee.
- The quadriceps
muscles were much more active in the female athletes (30-56% more
active, depending on which part of the quadriceps).
- The hamstring
muscle tested was 36% less active in the female athletes
The
combination of decreased gluteal activation and the hip/knee turning
inward places the ACL in a more vulnerable position.
The combination
of decreased hamstring activation and increased quadriceps activation
during the squat creates more of a forward shearing force on the
knee, leading to increased ACL strain (1-3).
Researchers noted less control with the female athletes,
which would likely then be magnified during more demanding activities
such as jumping/landing, planting/cutting, and deceleration from
sprinting.
The results of this study were supported two years later when analyzing
landing from a jump (5).
REFERENCES:
1. Hewett
TE, et al: Plometric training in female athletes: Decreased impact
forces and increased hamstring torques. Am J Sports Med 1996; 24:
765-76.
2. Baratta R, et al: Muscular coactivation: The role of the antagonist
musculature in maintaining knee stability. Am J Sports Med 1998; 16:113-22.
3. More RC, et al: Hamstrings - an anterior cruciate ligament protagonist:
An in-vitro study. Am J Sports Med 1993; 21: 231-7.
4. Zeller BL, McCrory JL, Kibler WB, Uhl TL: Differences in Kinematics
and Electromyographic Activity Between Men and Women during the Single-Legged
Squat. Am J Sports Med 2003; 31:449-456
5. Zazulak BT, Ponce PL, Straub SJ, et. al: Gender comparison of hip
muscle activity during single-leg landing. J Orthop Sports Phys Ther.
2005 May;35(5):292-9. |
