The effect of sex and age on isokinetic hip-abduction torques.
BACKGROUND
As high school female athletes demonstrate a rate of noncontact anterior cruciate ligament (ACL) injury 3-6 times higher than their male counterparts, research suggests that sagittal-plane hip strength plays a role in factors associated with ACL injuries.


OBJECTIVE
To determine if gender or age affect hip-abductor strength in a functional standing position in young female and male athletes.


METHODS
Prospective cohort design.


METHODS
Biomechanical laboratory.


METHODS
Over a 3-y time period, 852 isokinetic hip-abduction evaluations were conducted on 351 (272 female, 79 male) adolescent soccer and basketball players.


METHODS
Before testing, athletes were secured in a standing position, facing the dynamometer head, with a strap secured from the uninvolved side and extending around the waist just above the iliac crest. The dynamometer head was positioned in line with the body in the coronal plane by aligning the axis of rotation of the dynamometer with the center of hip rotation. Subjects performed 5 maximum-effort repetitions at a speed of 120°/s. The peak torque was recorded and normalized to body mass. All test trials were conducted by a single tester to limit potential interrater test error.


METHODS
Standing isokinetic hip-abduction torque.


RESULTS
Hip-abduction torque increased in both males and females with age (P < .001) on both the dominant and nondominant sides. A significant interaction of gender and age was observed (P < .001), which indicated that males experienced greater increases in peak torque relative to body weight than did females as they matured.


CONCLUSIONS
Males exhibit a significant increase in normative hip-abduction strength, while females do not. Future study may determine if the absence of similar increased relative hip-abduction strength in adolescent females, as they age, may be related to their increased risk of ACL injury compared with males.
Academy of Sports Performance, Cincinnati, OH, USA.
Jensen L
JL
Brent
Gregory D
GD
Myer
Kevin R
KR
Ford
Mark V
MV
Paterno
Timothy E
TE
Hewett
D000293:Adolescent; D000367:Age Factors; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D002648:Child; D005080:Exercise Test / Q000379:methods; D005260:Female; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007718:Knee Injuries / Q000209:etiology; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D011446:Prospective Studies; D012737:Sex Factors; D019415:Torque; D014481:United States