| Female athletes are substantially more susceptible than males
to suffer acute non-contact anterior cruciate ligament injury. A limited
number of studies have identified possible biomechanical risk factors
that differ between genders. The effect of fatigue on the biomechanics
of landing has also been inadequately investigated. The objective
of the study was to examine the effect of gender and fatigue on peak
values of biomechanical variables during landing from a jump. Thirty-two
recreational athletes performed bilateral drop jump landings from
a 40 cm platform. Kinetic, kinematic and electromyographic data were
collected before and after a functional fatigue protocol. Females
landed with 9° greater peak knee valgus (p = 0.001) and 140% greater
maximum vertical ground reaction forces (p = 0.003) normalized to
body weight compared to males. Fatigue increased peak foot abduction
by 1.7° (p = 0.042), peak rectus femoris activity by 27% (p = 0.018),
and peak vertical ground reaction force (p = 0.038) by 20%. The results
of the study suggest that landing with increased peak knee valgus
and vertical ground reaction force may contribute to increased risk
for knee injury in females. Fatigue caused significant but small changes
on some biomechanical variables. Anterior cruciate ligament injury
prevention programs should focus on implementing strategies to effectively
teach females to control knee valgus and ground reaction force.
KEY
WORDS: Anterior cruciate ligament injury, injury prevention,
knee injury, sports biomechanics.
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