title: The effect of fatigue on landing biomechanics in single-leg drop landings.
abstract: 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.
authors.affiliation: School of Kinesiology and Recreation Studies, James Madison University, Harrisonburg, Virginia 22807, USA. brazendm@gmail.com
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Brazen
authors.forename: M Kent
authors.initials: MK
authors.lastname: Todd
authors.forename: Jatin P
authors.initials: JP
authors.lastname: Ambegaonkar
authors.forename: Roshna
authors.initials: R
authors.lastname: Wunderlich
authors.forename: Connie
authors.initials: C
authors.lastname: Peterson
mesh_terms: 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