Short communicationContributions of individual muscles to hip joint contact force in normal walking
Introduction
The human hip joint withstands peak contact forces up to 4–5 times body weight during normal walking (Bergmann et al., 1993), rendering it susceptible to injury and structural deterioration over time. To assist in the prevention and management of hip joint conditions, knowledge of the contributions of individual muscles to hip joint loading during gait is needed. Whilst previous studies have used instrumented implants (Davy et al., 1988; Bergmann et al., 1993, 2001) and mathematical modeling techniques (Crowninshield et al., 1978; Rohrle et al., 1984; Heller et al., 2005) to determine hip joint loading during walking, the contributions of a comprehensive set of muscles to hip contact force remain unknown. Muscles crossing the hip can be expected to contribute directly to the contact force transmitted by the hip. Furthermore, since each muscle contributes to the accelerations of all the body segments due to dynamic coupling (Zajac and Gordon, 1989; Pandy, 2001), muscles that do not span the hip may also contribute to hip contact force.
The aim of the present study was threefold: first, to evaluate the relative contributions of muscle forces, gravitational forces, and centrifugal forces (i.e., forces arising from joint velocities) to hip contact force during gait; second, to determine which muscles contribute most significantly to the contact force; and third, to determine the extent to which non-hip-spanning muscles contribute to the hip contact force in normal walking.
Section snippets
Methods
Muscle contributions to the hip contact force were calculated based on the dynamic optimization solution for normal walking solved by Anderson and Pandy (2001a). The musculoskeletal model used to generate this solution was a 3D, 10-segment, 23 degree-of-freedom articulated linkage, actuated by 54 muscles. The pelvis was modeled as a rigid segment that could move freely with respect to the ground. Each hip was modeled as a ball-and-socket joint, each knee as a hinge joint, each ankle–subtalar
Results
Muscles were the major contributors to hip contact force with gravitational and centrifugal forces combined contributing less than 5% of the total contact force (Fig. 1 and Table 1). Four hip-spanning muscles – gluteus medius, gluteus maximus, iliopsoas, and hamstrings – were the major contributors to all three components of the hip contact force and hip contact impulse (Fig. 2 and Table 1). Gluteus medius contributed most to the superior and medial components of the contact force, while
Discussion
The resultant hip contact force predicted by the dynamic optimization solution was similar in shape and timing to the forces recorded from instrumented hip replacements implanted in elderly patients (Bergmann et al., 2001). Both model and experiment show the appearance of two peaks at identical points in the gait cycle. The model also predicted a resultant peak force of 4.3 BW for walking at the energetically optimal speed of 4.9 km/h (1.35 m/s) (Table 1, Total), which is consistent with the peak
Conflict of interest statement
The authors do not have any financial or personal relationships with other people or organizations that could inappropriately influence their work.
Acknowledgments
Financial support was provided by the Australian Research Council under Discovery Project Grants DP0772838 and DP0878785, National ICT Australia, and a VESKI Innovation Fellowship awarded to M.G.P.
References (13)
- et al.
Static and dynamic optimization solutions for gait are practically equivalent
Journal of Biomechanics
(2001) - et al.
Individual muscle contributions to support in normal walking
Gait & Posture
(2003) - et al.
Hip contact forces and gait patterns from routine activities
Journal of Biomechanics
(2001) - et al.
Hip joint loading during walking and running, measured in two patients
Journal of Biomechanics
(1993) - et al.
A biomechanical investigation of the human hip
Journal of Biomechanics
(1978) - et al.
Determination of muscle loading at the hip joint for use in pre-clinical testing
Journal of Biomechanics
(2005)