Stretching exercises of the hip flexors may be an easy but often ignored component of rehabilitation programs to improve gait, especially for the elderly. Reduced range of motion at the hip can be difficult to detect due to the significant amount of soft tissue surrounding the joint and to movements at the pelvis, which may subtly mask reduced hip extension. Although hip flexion contractures can be detected by bedside examinations such as the Thomas test, three-dimensional gait analysis best captures dynamic range of motion limitations. Walking is perhaps the only regular daily activity whereby the hip is fully extended, and indeed, hip flexion contractures are associated with immobility.1 Older adults who do not walk regularly may be particularly vulnerable to developing hip flexion contractures. Even for healthy older adults with no musculoskeletal defects, three-dimensional gait analysis has demonstrated reduced hip extension during walking compared with young adults.2
Whereas inability to walk can produce hip flexion contractures, hip flexion contractures can in turn hinder normal gait patterns. Hip flexion contractures can be compensated during gait through increased anterior pelvic tilting, decreased contralateral step length, and increased knee flexion. In one study examining the dynamic relationship between hip flexion contractures and their compensatory mechanisms, reduced hip extension was significantly correlated with anterior pelvic tilting and reduced contralateral step length.3 The graphs in Figures 1 and 2 depict the hip flexion and extension range and pelvic tilting during one gait cycle of a 92-yr-old male resident of an assisted-living facility. The x-axes are in units of frame samples (120 samples/sec) and the y-axes are in angle degrees based on a standardized protocol for measuring sagittal plane hip and pelvic positions and motions (Vicon Clinical Manager, Oxford Metrics). The solid line represents baseline walking, and the dotted line represents the patient’s gait after completion of a 10-wk hip extension stretching program. The hip extension stretching resulted not only in improved peak hip extension but also in improvements in variables that compensate for reduced hip extension, namely, anterior pelvic tilting and step length. For this patient, a 6-degree improvement in peak hip extension was associated with a 3-degree improvement in anterior pelvic tilting, a 0.30-m increase in step length (29% increase from baseline), and a 0.32-m/sec increase (37%) in self-determined comfortable gait velocity from baseline.
The above case and graphs are an example of how targeting one specific deficit (i.e., reduced hip flexion) can lead to improvements in other gait deficits (i.e., anterior pelvic tilt and contralateral step length) and bring about a more efficient gait pattern (as seen with increased gait velocity).
1. Kottke F: Therapeutic exercise to maintain mobility, in: Krusen’s Handbook of Physical Medicine and Rehabilitation
. Philadelphia, Saunders, 1990, pp 436–51
2. Kerrigan DC: Biomechanical gait alterations independent of speed in the healthy elderly: evidence for specific limiting impairments. Arch Phys Med Rehabil
3. Lee LW, Kerrigan DC, Della Croce U: Dynamic implications of hip flexion contractures. Am J Phys Med Rehabil