Muscle contributions to support and progression over a range of walking speeds

Abstract

Muscles actuate walking by providing vertical support and forward progression of the mass center. To quantify muscle contributions to vertical support and forward progression (i.e., vertical and fore-aft accelerations of the mass center) over a range of walking speeds, three-dimensional muscle-actuated simulations of gait were generated and analyzed for eight subjects walking overground at very slow, slow, free, and fast speeds. We found that gluteus maximus, gluteus medius, vasti, hamstrings, gastrocnemius, and soleus were the primary contributors to support and progression at all speeds. With the exception of gluteus medius, contributions from these muscles generally increased with walking speed. During very slow and slow walking speeds, vertical support in early stance was primarily provided by a straighter limb, such that skeletal alignment, rather than muscles, provided resistance to gravity. When walking speed increased from slow to free, contributions to support from vasti and soleus increased dramatically. Greater stance-phase knee flexion during free and fast walking speeds caused increased vasti force, which provided support but also slowed progression, while contralateral soleus simultaneously provided increased propulsion. This study provides reference data for muscle contributions to support and progression over a wide range of walking speeds and highlights the importance of walking speed when evaluating muscle function.

Evaluation of a geometry-based knee joint compared to a planar knee joint

“…The calculated muscle activation ( fig. 6) corresponds with activation levels and patterns published in other gait studies [22]. For both knee joints the predicted activation agreed with the captured EMG, however for some muscles a clear difference existed.…”

Are Muscle Volume Differences Related to Concentric Muscle Work During Walking in Spastic Hemiplegic Cerebral Palsy?

“…Concentric muscle work, also called positive muscle work, is defined as the sum of power generation a muscle produces when it shortens and, in the sagittal plane, is considered to be responsible for propulsion in gait [16,24]. Kinetic data that include concentric muscle work might be the key to understanding deviations in movement patterns and distinguishing compensatory mechanisms and could in addition be of help to develop and evaluate treatment strategies [8,12,26,27].…”

“…In addition, during gait, a bilateral shift of concentric muscle work from ankle plantar flexors to hip extensor muscles reportedly occurs in children with hemiplegic CP [24]. Although there are reports on muscle volume and muscle work, it is still unclear whether and how muscle volume influences gait [5,10,12,24].…”

Individual muscle contributions to ground reaction and to joint contact, ligament and bone forces during normal gait

“…This could provide insights into pathologic gait patterns [3], as well as the progression of joint disorders such as osteoarthritis [1,4]. Several studies have analysed how musculo-tendon forces contribute to ground reaction force [2,3,[5][6][7], acceleration of the centre of mass [8][9][10][11], whole-body angular momentum [12], angular accelerations of joints [13], linear and angular accelerations of segments [6], and joint moment at the ankle, knee and hip [2,4,14,15]. Studies have also analysed how musculo-tendon forces contribute to 3D hip joint contact force [2,16], the vertical component of 3D tibiofemoral joint contact force [2,4,14,[17][18][19], the vertical component of 3D ankle joint contact force [2] and femur force [20].…”

“…Most of the existing studies are based on a forward dynamics process with induced acceleration analysis [2,5,6,16] or perturbation analysis [3,9,13]. However, Lin et al [7] recently proposed an alternative method based on inverse dynamics and a static optimisation method using a pseudo-inverse.…”