Anatomical factors that impact female athletes’ risk of injury.
It is well known that high school female athletes are a 10 x higher risk of ACL injury compared to their male counterparts.
The reason for this is multi-facet and is a combination of anatomical, hormonal, and neuromuscular factors.
This three-part series is going to outline each of these risk factors and how they contribute to the heightened ACL injury rate we see in female athletes participating in cutting and pivoting sports such as netball!
With more than 400, 000 participants nationwide, netball is the number one sport chose to play by Australian females. Due to the nature of the game, intensity and demands on the body are high. The most common areas of the body injured during netball are the ankle and knee, with the most reported damage occurring to the anterior cruciate ligament (ACL).
As part one of a three-part article, part 1 looks to assess the anatomical factors that cause female athletes, particularly young netballers, to be more prone to injury.
Anatomical factors refer to the structural abnormalities or imbalances that occur within the human skeletal system. Anatomical differences between males and females may predispose female athletes to a higher risk of injury. The following three factors related to anatomical differences indicate why females may be more prone to injury, in particular, a risk of damage to their ACL.
Quadriceps (Q) Angle
The Q angle of the knee is the measurement of the angle between the quadriceps muscle and the kneecap. It provides vital information in regards to the alignment of the knees. Females have a greater Q-angle compared to males due to an increased pelvis width. An increased Q-angle may help explain the discrepancy between the prevalence of ACL injury between males and females (2). Having a greater Q angle means there is a greater tibial femoral rotational force (rotation of the knee in towards the midline) and increased knee valgus motion (motion of the knees coming together, commonly recognized as knocked knees).
Having knees that are more likely to rotate inwards when jumping and landing is a very big risk factor for young female netballers sustaining an ACL injury.
Intercondylar Notch Width
The intercondylar notch is the grove between the two nobly ends (condyles) of your thigh bone (femur) closest to your knee. This grove is where your cruciate ligaments, such as the ACL attach. This notch can be rounded or triangular in some individuals. If the notch is smaller than 17 mm, there is a 6-fold increase in the risk of sustaining an ACL injury compared to athletes who have a notch greater than 17mm. The intercondylar notch of the femur in females is usually narrower in comparison to males.
Research has shown that smaller intercondylar notch significantly increased the incidence of an ACL tear. There are no differences in ACL injury rates between males and females due to notch width but more so to do with a smaller groove creating a weaker ACL, predisposing the knee to injury.
Females have a smaller intercondylar notch, meaning causing the ACL to be more fragile, which may make females netball athletes more prone to an ACL injury.
Compared to males, females have a higher prevalence of hypermobility syndrome, increased joint laxity, and hamstring flexibility. Having increased hamstring flexibility heightens the risk of placing the knee in hyperextension (excessively straightened) and performing valgus motion (knocked knees) predisposing female athletes to ACL injury. If the hamstrings are overly flexible, co-contraction of the quadriceps and hamstrings are delayed which results in higher forces being placed on the ACL during deceleration and landing.
Hypermobility is very common in young female athletes (extreme flexibility at the joints). Being hypermobile has been shown to reduce joint proprioception (varying muscle contraction as an immediate response) and thus be seen as a risk factor for injury in female athletes.
Anatomical factors have a role in determining injury risk in young female netball athletes. These factors are unfortunately un-modifiable but important to keep in mind when learning how prone female netball athletes are to injury. Stay tuned for Part 2 and 3 to find out more about the impact of hormonal and neuromuscular risk factors on injury in female netball athletes in addition to what factors can be modified to reduce injury risk.
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- Smith R, Damodaran AK, Swaminathan S, Campbell R, and Barnsley L. Hypermobility and sports injuries in junior netball players. British Journal of Sports Medicine 39: 628-631, 2005.
- http://www.abs.gov.au/ausstats/[email protected]/Products/8F88DA9AC6E141AACA 257AD900 0E2666?opendocument.