The effect of fatigue on landing biomechanics in single-leg drop landings.
OBJECTIVE
To examine the effects of fatigue on landing biomechanics in single-leg drop landings.


METHODS
Quasi-experimental.


METHODS
Controlled research laboratory.


METHODS
Twenty-four healthy individuals (12 women and 12 men).


METHODS
Participants performed 3 single-leg drop landings from a height of 0.36 m before and after a fatiguing protocol.


METHODS
Sagittal ankle flexion, sagittal knee flexion, and frontal knee valgus angles (degrees) at initial ground contact; vertical ground reaction forces (N); and time to stabilization (TTS) were compared between sexes and before (pre) and after (post) the fatiguing protocol.


RESULTS
After fatigue, participants landed with greater knee flexion [P = 0.001; pre 142.58 (14.35) degrees; post 136.12 (14.48) degrees] and ankle plantar flexion [P = 0.012; pre 79.04 (6.96) degrees; post 80.78 (6.13) degrees], and higher peak vertical ground reaction forces (P = 0.002; pre 2202.5 (536.29) N to post 2537.86 (469.66) N] but did not show changes in frontal knee angles [P = 0.815; pre, 7.94 (3.74) degrees; post, 8.08 (4.33) degrees]. Participants had higher anterior-posterior TTS [P = 0.021; pre 1.73 (0.53) seconds to post 1.93 (0.53) seconds] and vertical TTS [P = 0.002; pre 0.65 (0.24) seconds to post 0.93 (0.37) seconds] with a significant interaction noted in medial-lateral TTS [P = 0.043; pre 1.49 (0.64) seconds to post 1.61 (0.67) seconds]. No significant sex differences existed across any of the examined variables.


CONCLUSIONS
When landing after fatigue, participants had greater knee and ankle flexion angles at initial contact, had greater peak ground reaction forces, and required longer times to stabilize the body after landing, regardless of sex. Overall, fatigue clearly affects lower body biomechanics during single-leg landings. Whether these changes actually increase injury risk during activity warrants further investigation.
Brazen
Danielle M
DM
School of Kinesiology and Recreation Studies, James Madison University, Harrisonburg, Virginia 22807, USA. brazendm@gmail.com
Todd
M Kent
MK
Ambegaonkar
Jatin P
JP
Wunderlich
Roshna
R
Peterson
Connie
C
D000328:Adult; D001265:Athletic Injuries / Q000503:physiopathology; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D012737:Sex Factors