The influence of hip abductor weakness on frontal plane motion of the trunk and pelvis in patients with cerebral palsy.
In CP gait, weak hip abductors create only a slight trunk lean while the pelvis stays flat—so probe trunk control too.
01Research in Context
What this study did
Bigham et al. (2013) watched how kids with cerebral palsy walk.
They checked hip-abductor strength and measured how far the trunk leaned sideways.
The pelvis angle was recorded at the same time.
What they found
Weak hip abductors made the trunk lean a little more to the same side.
The pelvis stayed level, so the trunk did all the compensating.
The link was small, meaning other causes matter too.
How this fits with other research
Heyrman et al. (2014) extends this view. They gave seated trunk-control tests and saw that kids who scored low swayed more in the thorax while walking. Hip strength alone did not tell the whole story.
Saether et al. (2014) used trunk-worn accelerometers and found higher trunk accelerations and asymmetry in CP gait, especially when kids walked faster. Their data agree that the trunk, not the pelvis, shows the main motion.
Ágústsson et al. (2017) looked at adults with tight hip flexors and found pelvic tilt and scoliosis. The body region differs, but the pattern is the same: hip problems show up as trunk or pelvic asymmetry.
Why it matters
When you see a client with CP leaning sideways, do not blame only weak hip abductors. Check seated trunk control and watch how the thorax moves. Add trunk-stability drills or external support before you spend weeks on hip-strength circuits. A quick TCMS screen or a Wii Fit weight-shift game can tell you if the trunk is the real weak link.
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02At a glance
03Original abstract
Trendelenburg walking pattern is a common finding in various disorders, including cerebral palsy (CP), where it is seen in children and adults. Clinically, this deviation is viewed as a consequence of hip abductor weakness resulting in pelvic obliquity. Trunk lean to the ipsilateral side is a common compensatory mechanism to counteract pelvic obliquity and to maintain gait stability. However, no published investigations objectively address pelvic and trunk motions in the frontal plane or examine the correlation with hip abductor weakness in patients with CP. We selected 375 ambulatory (GMFCS I-III) patients with spastic bilateral CP and 24 healthy controls from our gait laboratory database. They had all undergone a standardized three-dimensional analysis of gait, including trunk motion, and a clinical examination including hip abductor strength testing. Selected frontal plane kinematic and kinetic parameters were investigated and statistically tested for correlation (Spearman rank) with hip abductor strength. Only a weak (r=0.278) yet highly significant correlation between trunk lean and hip abductor strength was found. Hip abductor weakness was accompanied by decreased hip abduction moment. However, no significant differences in pelvic position were found between the different strength groups, indicating that the pelvis remained stable regardless of the patients' strength. Our findings indicate that weak hip abductors in patients with CP are accompanied by increased trunk lean to the ipsilateral side while pelvic position is preserved by this compensatory mechanism. However, since this correlation is weak, other factors influencing lateral trunk lean should be considered. In patients with severe weakness of the hip abductors compensatory trunk lean is no longer fully able to stabilize the pelvis, and frontal pelvic kinematics differs from normal during loading response. The results indicate that the stable pelvic position seems to be of greater importance than trunk position for patients with CP. Further studies are needed to investigate other factors influencing lateral trunk lean.
Research in developmental disabilities, 2013 · doi:10.1016/j.ridd.2012.12.018