title: Comparison of lower extremity kinematics and hip muscle activation during rehabilitation tasks between sexes.
abstract: BACKGROUND
  Closed kinetic chain exercises are an integral part of rehabilitation programs after lower extremity injury. Sex differences in lower extremity kinematics have been reported during landing and cutting; however, less is known about sex differences in movement patterns and activation of the hip musculature during common lower extremity rehabilitation exercises.
  
  
  OBJECTIVE
  To determine whether lower extremity kinematics and muscle activation levels differ between sexes during closed kinetic chain rehabilitation exercises.
  
  
  METHODS
  Cross-sectional with 1 between-subjects factor (sex) and 1 within-subjects factor (exercise).
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Participants included 21 women (age = 23 +/- 5.8 years, height = 167.6 +/- 5.1 cm, mass = 63.7 +/- 5.9 kg) and 21 men (age = 23 +/- 4.0 years, height = 181.4 +/- 7.4 cm, mass = 85.6 +/- 16.5 kg).
  
  
  METHODS
  In 1 testing session, participants performed 3 trials each of single-leg squat, lunge, and step-up-and-over exercises.
  
  
  METHODS
  We recorded the peak joint angles (degrees) of knee flexion and valgus and hip flexion, extension, adduction, and external rotation for each exercise. We also recorded the electromyographic activity of the gluteus maximus, rectus femoris, adductor longus, and bilateral gluteus medius muscles for the concentric and eccentric phases of each exercise.
  
  
  RESULTS
  Peak knee flexion angles were smaller and peak hip extension angles were larger for women than for men across all tasks. Peak hip flexion angles during the single-leg squat were smaller for women than for men. Mean root-mean-square amplitudes for the gluteus maximus and rectus femoris muscles in both the concentric and eccentric phases of the 3 exercises were greater for women than for men.
  
  
  CONCLUSIONS
  Sex differences were observed in sagittal-plane movement patterns during the rehabilitation exercises. Because of the sex differences observed in our study, future researchers need to compare the findings for injured participants by sex to garner a better representation of altered kinematic angles and muscle activation levels due to injury.
authors.affiliation: University of Kentucky, Lexington, KY 40536, USA. Maureen.Dwyer@uky.edu
authors.forename: Maureen K
authors.initials: MK
authors.lastname: Dwyer
authors.forename: Samantha N
authors.initials: SN
authors.lastname: Boudreau
authors.forename: Carl G
authors.initials: CG
authors.lastname: Mattacola
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Uhl
authors.forename: Christian
authors.initials: C
authors.lastname: Lattermann
mesh_terms: D000704:Analysis of Variance; D001265:Athletic Injuries / Q000503:physiopathology* / Q000534:rehabilitation*; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D004576:Electromyography; D005260:Female; D006621:Hip Joint / Q000503:physiopathology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D035002:Lower Extremity / Q000293:injuries*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology*; D012737:Sex Factors; D055815:Young Adult