title: Two different fatigue protocols and lower extremity motion patterns during a stop-jump task.
abstract: BACKGROUND
  Altered neuromuscular control strategies during fatigue probably contribute to the increased incidence of noncontact anterior cruciate ligament injuries in female athletes.
  
  
  OBJECTIVE
  To determine biomechanical differences between 2 fatigue protocols (slow linear oxidative fatigue protocol [SLO-FP] and functional agility short-term fatigue protocol [FAST-FP]) when performing a running-stop-jump task.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Laboratory.
  
  
  METHODS
  A convenience sample of 15 female soccer players (age = 19.2 ± 0.8 years, height = 1.67 ± 0.05 m, mass = 61.7 ± 8.1 kg) without injury participated.
  
  
  METHODS
  Five successful trials of a running-stop-jump task were obtained prefatigue and postfatigue during the 2 protocols. For the SLO-FP, a peak oxygen consumption (Vo(2)peak) test was conducted before the fatigue protocol. Five minutes after the conclusion of the Vo(2)peak test, participants started the fatigue protocol by performing a 30-minute interval run. The FAST-FP consisted of 4 sets of a functional circuit. Repeated 2 (fatigue protocol) × 2 (time) analyses of variance were conducted to assess differences between the 2 protocols and time (prefatigue, postfatigue).
  
  
  METHODS
  Kinematic and kinetic measures of the hip and knee were obtained at different times while participants performed both protocols during prefatigue and postfatigue.
  
  
  RESULTS
  Internal adduction moment at initial contact (IC) was greater during FAST-FP (0.064 ± 0.09 Nm/kgm) than SLO-FP (0.024 ± 0.06 Nm/kgm) (F(1,14) = 5.610, P = .03). At IC, participants had less hip flexion postfatigue (44.7° ± 8.1°) than prefatigue (50.1° ± 9.5°) (F(1,14) = 16.229, P = .001). At peak vertical ground reaction force, participants had less hip flexion postfatigue (44.7° ± 8.4°) than prefatigue (50.4° ± 10.3°) (F(1,14) = 17.026, P = .001). At peak vertical ground reaction force, participants had less knee flexion postfatigue (-35.9° ± 6.5°) than prefatigue (-38.8° ± 5.03°) (F(1,14) = 11.537, P = .001).
  
  
  CONCLUSIONS
  Our results demonstrated a more erect landing posture due to a decrease in hip and knee flexion angles in the postfatigue condition. The changes were similar between protocols; however, the FAST-FP was a clinically applicable 5-minute protocol, whereas the SLO-FP lasted approximately 45 minutes.
authors.affiliation: Human Movement Sciences Department, Old Dominion University, Norfolk, VA, USA.
authors.forename: David
authors.initials: D
authors.lastname: Quammen
authors.forename: Nelson
authors.initials: N
authors.lastname: Cortes
authors.forename: Bonnie L
authors.initials: BL
authors.lastname: Van Lunen
authors.forename: Shawn
authors.initials: S
authors.lastname: Lucci
authors.forename: Stacie I
authors.initials: SI
authors.lastname: Ringleb
authors.forename: James
authors.initials: J
authors.lastname: Onate
mesh_terms: D016118:Anterior Cruciate Ligament; D056352:Athletes; D001696:Biomechanical Phenomena; D005221:Fatigue / Q000503:physiopathology*; D005260:Female; D006615:Hip / Q000502:physiology; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007717:Knee / Q000502:physiology; D035002:Lower Extremity / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010101:Oxygen Consumption; D011187:Posture / Q000502:physiology*; D016059:Range of Motion, Articular; D012420:Running; D012916:Soccer; D055815:Young Adult