Crouched postures reduce the capacity of muscles to extend the hip and knee during the single-limb stance phase of gait

Abstract

Many children with cerebral palsy walk in a crouch gait that progressively worsens over time, decreasing walking efficiency and leading to joint degeneration. This study examined the effect of crouched postures on the capacity of muscles to extend the hip and knee joints and the joint flexions induced by gravity during the single limb stance phase of gait. We first characterized representative mild, moderate, and severe crouch gait kinematics based on a large group of subjects with cerebral palsy (N = 316). We then used a three-dimensional model of the musculoskeletal system and its associated equations of motion to determine the effect of these crouched gait postures on (1) the capacity of individual muscles to extend the hip and knee joints, which we defined as the angular accelerations of the joints, towards extension, that resulted from applying a 1 N muscle force to the model, and (2) the angular acceleration of the joints induced by gravity. Our analysis showed that the capacities of almost all the major hip and knee extensors were markedly reduced in a crouched gait posture, with the exception of the hamstrings muscle group, whose extension capacity was maintained in a crouched posture. Crouch gait also increased the flexion accelerations induced by gravity at the hip and knee throughout single limb stance. These findings help explain the increased energy requirements and progressive nature of crouch gait in patients with cerebral palsy.

Spastic diparetic does not directly affect the capacity to ascend and descend access ramps: three-dimensional analysis

“…This strategy was observed as being influenced by the inclination surface but not by the group type, which for some researchers (4,5), is due to the DG flexor pattern. This would lead to less dynamic hip extension, evidenced for the DG in the 3 conditions, with notable difference during descent.…”

“…This would happen as a compensation due to the decrease in extension capability of these children (5,32) and in the flexed knee gait by the gait pattern and the weakness of the extensor muscles of knee and hip joint (32). The proportional increase to the ramp's inclination would occur as a means to follow the movement and allow increased hip flexion, coinciding with simple support on each side (17,26).…”

“…These children generally adopted different walking strategies, most of them with crouched gait, knee internal rotation, anterior pelvic tilt (4) with toe-walking (5). These individuals' necessities of accessibility structures that not always were investigated about yours biomechanics advantages, and the motion effectiveness.…”

The Architectural Design of the Gluteal Muscle Group: Implications for Movement and Rehabilitation

“…This has been demonstrated previously in children with cerebral palsy. 12 Also, the net effect on hip extension would be relatively minor, as the hamstrings, gluteus maximus, and adductor magnus all contribute to hip extension moment-generating capacity. Although these muscle-level changes seem to fit previously described movement patterns observed in patients, it should be noted that within the framework of this model the changes are fairly small and appear to occur deeper in hip and knee flexion than expected.…”

Flexed-knee gait in children with cerebral palsy: A 10-year follow-up study

“…With regard to hamstring lengthening, there are concerns that this procedure decreases hip extension and increases pelvic tilt [10]. In this cohort of mixed surgical procedures, there was no significant increase in anterior pelvic tilt at 10 years follow-up.…”