The
number of female athletes participating in sports is taking a giant leap forward,
practicing and competing at a higher level of intensity than in the past. Unfortunately,
the incidence of ACL injuries in females is also rising. MECHANISM
OF INJURY
"Women are two times as likely to have an ACL injury as a result
of player contact and three times more likely to obtain such an injury through
noncontact mechanisms than their male counterpart" (1).
The majority of ACL injuries happen during practice or competition and most often
in basketball, volleyball, or soccer where a great deal of cutting and quick movements
happen. There are two kinds of mechanisms that can cause an ACL tear, noncontact
and contact. Non-contact
mechanisms of ACL injuries (5):
- Planting and cutting--athlete who is running and decelerates quickly, with
or without pivoting, causing a rotational force on the knee.
- Straight knee landing--athlete who jumps and lands with their knee locked
out in full extension causing a large compression force.
- One step stop landing with knee hyperextension--the ACL is stretched beyond
its limits.
Contact
mechanisms of ACL injuries (2):
- Direct blow--athlete who is hit from the posterior aspect of the knee
causing the tibia to move anteriorly, or from the lateral side causing a
rotational force onto the tibia.
Contributing
Factors
The anatomical differences between men and women may play a role
in injury incidence. Intrinsic
factors: Intrinsic factors are related to the anatomy, biomechanics and other
physiologic factors of a woman's body (1,
6).
- Intercondylar notch--This notch is a groove in the bone where the ACL travels
through as it attaches to the base of the femur. The size and shape of the
notch tends to be smaller in women, possibly shearing on the ACL .
- Pelvis size--women typically have a wider pelvis, which makes the thigh bones
come down at a greater angle as it sits on the tibia. This results in a greater "Q" angle,
and subsequently causes the knee to bend inward,. The wider the angle, the
more pressure put through the medial aspect of the knee.
- Hormones--changes in estrogen levels may effect the strength of the ligaments.
- Ligament laxity--excessive joint motion can predispose a woman to injury.
- Other specific factors--less muscular thigh development, less developed VMO,
increased flexibility/hyperextension, genu valgum, external tibial torsion.
Extrinsic factors:
This involves other influences other than mechanical disadvantages (1,
6).
- Level of experience--less exposure
to the activity makes the more complex movements more difficult
- Muscle strength and coordination--athlete may be over or under developed in
certain areas (quadriceps and medial hamstring muscles in particular).
- Level of skill--playing with athletes of the same age, but different skill
level.
PREVENTION
Rising awareness has caused many practitioners to take an interest in making
a protocol designed towards prevention of an ACL injury. One research study followed
the injury rates of 1,300 athletes participating in soccer, volleyball, and basketball.
The purpose was to focus on reducing the level of serious knee injuries (3,
4).
The
program consisted of:
- 6 week pre season neuromuscular training
- Leg muscle strength testing and training
- Safety recommendations of recognition of susceptible positions and avoidance
- Avoiding any straight knee landing, one-step stop landing (quick landing),
and sharp planting and cutting
Four basic techniques were
stressed:
- Correct posture and body alignment throughout the jump
- Jumping straight up with no excessive side-to-side or forward-backward movement
- Soft landings including heel toe-to-heel rocking and bent knees and
- Instant recoil preparation for the next jump.
The
program followed a few basic guidelines:
- Verbal commands to inhance
performance were used throughout the sessions.
- Fundamental phase concentrated on building a base of strength, power
and agility.
- Performance phase focuses on achieving maximum vertical jump height.
- Stretching was done prior to the training.
- Weight training for upper and lower body was performed after training
with a 15 minute rest period.
The
results of this study were ten knee injuries in the non-trained group and only
two injuries in the trained group. The results suggest that neuromuscular training
can decrease knee injuries in female athletes (3).
CONCLUSION
- It is important for female athletes to be correctly trained in their sports
earlier and use training protocols that will strengthen both the quadriceps and
hamstrings. Coaches and athletes also need to be informed of proper jumping and
landing mechanisms.
- There is not one main factor causing the increase of ACL injuries in women,
it seems to be a multiple of factors including both intrinsic and extrinsic factors.
- The athlete needs to
be physically prepared for the level of competition, regardless of what type of
experience they have had in the past. REFERENCES
1. Arendt, Elizabeth & Dick, Randall.
(1995). Knee injury patterns among men and women in collegiate basketball and
soccer. American Journal of Sports Medicine. Vol.23, No.6, pp.694-701.
2.
Arnheim, Daniel D. & Prentice, William E. (1997). Principles of Athletic Training
(9th edition). Madison, Wisconsin: Brown & Benchmark.
3.
Hewett, Timothy E. (1998). Cincinnati Sportsmetrics: A training program for the
preventions of knee injuries in female athletes. Sports and Medicine Today. Vol.
1 No.1 pp. 63-66. 4.
McGee, Patrick. (1998). Training may reduce knee injuries for female athletes.
Orthopedics Today. pp.12-16. 5.
Moeller, James L. & Lamb, Mary M. (1997). Anterior Cruciate Ligament Injuries
in Female athletes: why women are more susceptible? Physician and Sportsmendicine.
Vol. 25, No. 4, pp. 1-9. 6.
Rochman, Sue. (1996). Gender inequity. Training and Conditioning. Vol. 6, No.
5. pp. 10-20. |
