Lower extremity energy absorption and biomechanics during landing, part I: sagittal-plane energy absorption analyses.
BACKGROUND
Eccentric muscle actions of the lower extremity absorb kinetic energy during landing. Greater total sagittal-plane energy absorption (EA) during the initial impact phase (INI) of landing has been associated with landing biomechanics considered high risk for anterior cruciate ligament (ACL) injury. We do not know whether groups with different INI EA magnitudes exhibit meaningful differences in ACL-related landing biomechanics and whether INI EA might be useful to identify ACL injury-risk potential.


OBJECTIVE
To compare biomechanical factors associated with noncontact ACL injury among sagittal-plane INI EA groups and to determine whether an association exists between sex and sagittal-plane INI EA group assignment to evaluate the face validity of using sagittal-plane INI EA to identify ACL injury risk.


METHODS
Descriptive laboratory study.


METHODS
Research laboratory.


METHODS
A total of 82 (41 men, 41 women; age = 21.0 ± 2.4 years, height = 1.74 ± 0.10 m, mass = 70.3 ± 16.1 kg) healthy, physically active individuals volunteered.


METHODS
We assessed landing biomechanics using an electromagnetic motion-capture system and force plate during a double-legged jump-landing task.


METHODS
Total INI EA was used to group participants into high, moderate, and low tertiles. Sagittal- and frontal-plane knee kinematics; peak vertical and posterior ground reaction forces (GRFs); anterior tibial shear force; and internal hip extension, knee extension, and knee varus moments were identified and compared across groups using 1-way analyses of variance. We used a χ (2) analysis to compare male and female representation in the high and low groups.


RESULTS
The high group exhibited greater knee-extension moment and posterior GRFs than both the moderate (P < .05) and low (P < .05) groups and greater anterior tibial shear force than the low group (P < .05). No other group differences were noted. Women were not represented more than men in the high group (χ(2) = 1.20, P = .27).


CONCLUSIONS
Greater sagittal-plane INI EA likely indicates greater ACL loading, but it does not appear to influence frontal-plane biomechanics related to ACL injury. Women were not more likely than men to demonstrate greater INI EA, suggesting that quantification of sagittal-plane INI EA alone is not sufficient to infer ACL injury-risk potential.
College of Public Health and Human Sciences, Oregon State University, Corvallis.
Marc F
MF
Norcross
Michael D
MD
Lewek
Darin A
DA
Padua
Sandra J
SJ
Shultz
Paul S
PS
Weinhold
J Troy
JT
Blackburn
D000328:Adult; D016118:Anterior Cruciate Ligament / Q000502:physiology; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena / Q000502:physiology*; D001842:Bone and Bones / Q000502:physiology; D004735:Energy Transfer / Q000502:physiology*; D005260:Female; D006801:Humans; D007717:Knee / Q000502:physiology*; D007718:Knee Injuries; D007719:Knee Joint / Q000502:physiology*; D007866:Leg / Q000502:physiology*; D008297:Male; D011187:Posture / Q000502:physiology; D012737:Sex Factors; D033081:Shear Strength / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult