Can strength training predictably improve gait kinematics? A pilot study on the effects of hip and knee extensor strengthening on lower-extremity alignment in cerebral palsy.
BACKGROUND
Computer simulations have demonstrated that excessive hip and knee flexion during gait, as frequently seen in ambulatory children with cerebral palsy (CP), can reduce the ability of muscles to provide antigravity support and increase the tendency of hip muscles to internally rotate the thigh. These findings suggest that therapies for improving upright posture during gait also may reduce excessive internal rotation.


OBJECTIVE
The goal of this study was to determine whether strength training can diminish the degree of crouched, internally rotated gait in children with spastic diplegic CP.


METHODS
This was a pilot prospective clinical trial.


METHODS
Eight children with CP participated in an 8-week progressive resistance exercise program, with 3-dimensional gait analysis and isokinetic testing performed before and after the program. Secondary measures included passive range of motion, the Ashworth Scale, and the PedsQL CP Module. To identify factors that may have influenced outcome, individual and subgroup data were examined for patterns of change within and across variables.


RESULTS
Strength (force-generating capacity) increased significantly in the left hip extensors, with smaller, nonsignificant mean increases in the other 3 extensor muscle groups, yet kinematic and functional outcomes were inconsistent. The first reported subject-specific computer simulations of crouch gait were created for one child who showed substantial benefit to examine the factors that may have contributed to this outcome.


CONCLUSIONS
The sample was small, with wide variability in outcomes.


CONCLUSIONS
Strength training may improve walking function and alignment in some patients for whom weakness is a major contributor to their gait deficits. However, in other patients, it may produce no change or even undesired outcomes. Given the variability of outcomes in this and other strengthening studies in CP, analytical approaches to determine the sources of variability are needed to better identify those individuals who are most likely to benefit from strengthening.
Damiano
Diane L
DL
Functional and Applied Biomechanics Section, Rehabilitation Medicine Department, NIH Clinical Center, Bldg 10, Room 1-1469, Bethesda, MD 20892, USA. damianod@cc.nih.gov
Arnold
Allison S
AS
Steele
Katherine M
KM
Delp
Scott L
SL
D000293:Adolescent; D001696:Biomechanical Phenomena; D002547:Cerebral Palsy / Q000503:physiopathology / Q000534:rehabilitation*; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D005260:Female; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000502:physiology*; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D026741:Physical Therapy Modalities; D010865:Pilot Projects; D016059:Range of Motion, Articular / Q000502:physiology*; D055070:Resistance Training / Q000379:methods*