Since the passage of the Title IX Educational Assistance Act of 1972 (requiring institutions receiving federal funds to provide equal access to men and women in both curricular and extra-curricular activities), the numbers of female participants has exponentially increased.1 Some of the advantages of this increase are:
A pattern has surfaced over the last decade of an increased incidence of anterior cruciate injuries in female athletes. One stark example was in the 1988 Olympic basketball tryouts, where both male and female injury rates were documented.2 Eighty-one per cent of the ACL injuries were sustained by the female athletes! These injury rates were similar to those found with other sports, such as volleyball, rugby, and soccer.1,3 These and other studies have struggled to determine why females are more prone to injury than males given the same sport activity. A fine review was published by Traina and Bromberg detailing some of the current thinking in this area.4 The following is a synopsis of their work.
The theories regarding a female predisposition to ACL injury generally fall into two general categories: (1) extrinsic factors, and (2) intrinsic factors. The extrinsic factors focus on conditioning and training. Some questions are:
It is clear that the vast majority (78% in one study) of ACL injuries are noncontact, often occurring when landing from a jump.7 This is even more true in sports such as basketball and volleyball. One study divided these noncontact injuries into three types and documented the percentage of incidence.8 Together they account for most ACL injuries in the study, and individually are essentially equal in occurrence (26%-29%):
It is clear that women have less hamstring and quadriceps strength when compared to males; however, this holds true even when body weight is factored in.9 This is a clear signal that a focus on general knee strength training should be part of all women's pre-event training schedule. It appears that another factor is the recruitment of muscles. In one study, females were more inclined to use quadriceps contraction when an anterior tibial force was applied, as compared to males, who used hamstring contraction.9 It is clear that the hamstring contraction is the more protective response and suggests a possible gender or lack-of-training effect that must be corrected prior to event performance.
The time to torque production for hamstring contraction differs between male and female athletes. It appears that males have a quicker response time when compared to females.9 There may be a training effect at play, yet what should be incorporated into women's training programs is proprioceptive training with the goal of decreasing response time to imposed demands. One study indicated that this could be accomplished through a progressive stability challenge program using balance and rocker boards.10 Training begins first with the patient seated while the trainer attempts to move the unbalanced platform out from under the patient's foot. This progresses to more challenging positioning with less support available.
Intrinsic factors that may predispose females to ACL injury include instability at the knee, a wide pelvis (affecting limb alignment), and size of the intercondylar notch. It has long been noted that women appear to have "looser" joints than males. Does this static laxity play a part, or is the determining factor more the combination of capsular/ligament laxity and muscle strength?
There has been an assumption that hormonal influences allow for more flexibility and therefore laxity of female's ligaments. Yet, two studies using an objective measurement of ACL laxity with the KT-1000 did not demonstrate a gender specific laxity of the ACL.11,12 Disagreement regarding the role of ACL laxity as a cause of ACL injury still exists. Although joint laxity may predispose an athlete to injury, it appears that other factors are important, such as muscle strength and reaction time (discussed above).
Although the female predisposition for patellar tracking problems seems to be related to a wider pelvis, femoral anteversion, and increased genu valgum as compared to men, these factors have not been shown to influence predisposition to ACL injury.13
An interesting finding has been an apparent relationship between the intercondylar notch size and ACL injury. It appears that many athletes with ACL injury have a smaller notch size, and women in general have smaller notch sizes.14 Radiographically, this is measured with the notch width index (ratio of intercondylar notch width to distal femur width) measured at the level of the popliteal groove on a tunnel view.14 This smaller notch (stenotic notch) may indicate a smaller ACL or an increased tendency for impingement and stress to the ACL.
Even if the factors of notch width, pelvis width, and inherent joint laxity are factors, they generally can't be modified. The focus, therefore, should remain on proper training to ensure proper hamstring and quadriceps strength, decrease in reaction time, and proper recruitment sequence of muscle firing.
References
When I graduated from chiropractic college in 1981 and started practice, I heard it all, and very little was positive. “You are a quack; you do not know what a subluxation is; you couldn’t get into a real health care program, so you chose the one that is slightly above a mail-order degree; you have no proof that chiropractic works; Are you really licensed?”, and so much more.
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A central challenge in creating our identity is that chiropractic is a method of care, not a technique or procedure. This is an important concept for us to promote. Our patients are treated with lifestyle modification, exercise, nutritional supplements, diet and a whole-body approach to accelerate the natural healing process. We are not simply CMT providers.
The results of a global survey released late last year (2023) unveiled some startling findings among medical and nursing students. The “Clinician of the Future: 2023 Education Edition” surveyed 2,212 students, of which 446 were in the United States, from 91 countries.
