Comparison of lower extremity kinematics and hip muscle activation during rehabilitation tasks between sexes.
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.
Dwyer
Maureen K
MK
University of Kentucky, Lexington, KY 40536, USA. Maureen.Dwyer@uky.edu
Boudreau
Samantha N
SN
Mattacola
Carl G
CG
Uhl
Timothy L
TL
Lattermann
Christian
C
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