Trunk's Natural Inclination Influences Stance Limb Kinetics, but Not Body Kinematics, during Gait Initiation in Able Men

Abstract

The imposing mass of the trunk in relation to the whole body has an important impact on human motion. The objective of this study is to determine the influence of trunk's natural inclination - forward (FW) or backward (BW) with respect to the vertical - on body kinematics and stance limb kinetics during gait initiation.Twenty-five healthy males were divided based on their natural trunk inclination (FW or BW) during gait initiation. Instantaneous speed was calculated at the center of mass at the first heel strike. The antero-posterior impulse was calculated by integrating the antero-posterior ground reaction force in time. Ankle, knee, hip and thoraco-lumbar (L5) moments were calculated using inverse dynamics and only peaks of the joint moments were analyzed. Among all the investigated parameters, only joint moments present significant differences between the two groups. The knee extensor moment is 1.4 times higher (P<0.001) for the BW group, before the heel contact. At the hip, although the BW group displays a flexor moment 2.4 times higher (P<0.001) before the swing limb's heel-off, the FW group displays an extensor moment 3.1 times higher (P<0.01) during the swing phase. The three L5 extensor peaks after the toe-off are respectively 1.7 (P<0.001), 1.4 (P<0.001) and 1.7 (P<0.01) times higher for the FW group. The main results support the idea that the patterns described during steady-state gait are already observable during gait initiation. This study also provides reference data to further investigate stance limb kinetics in specific or pathologic populations during gait initiation. It will be of particular interest for elderly people, knowing that this population displays atypical trunk postures and present a high risk of falling during this forward stepping.

Sagittal Plane Trunk Posture Influences Patellofemoral Joint Stress During Running

“…For example, a forward trunk lean posture has been found to be associated with lower knee extensor moments during walking, stair ascent, and single-leg-hop landing. 3,24,30 Based on these findings, modifying sagittal plane trunk posture may provide an alternative means to reduce PFJ stress during running.…”

“…3,24,30 Asay et al 3 reported that a 6.3° increase in the trunk flexion angle was associated with a 35.2% lower peak knee extensor moment during stair ascent. In addition, Oberländer et al 30 reported that a 6° greater forward trunk lean resulted in a 15% reduction in peak knee extensor moment during hop landing.…”

Individuals with isolated patellofemoral joint osteoarthritis exhibit higher mechanical loading at the knee during the second half of the stance phase

“…As a result, the ground reaction force passes posteriorly to the knee joint center and leads to knee flexion moment. Recent studies showed that a slightly more forward-lean trunk posture is related to lower knee flexion moment and PFJ stress during walking and running [11, 40]. Moreover, increasing step rate and decreasing step length have been shown to reduce PFJ stress and knee flexion moment during running [32, 41] Future studies are warranted to investigate the effects of these gait modifications (i.e.…”

Increasing trunk flexion morphs human leg function into that of birds despite different leg morphology

“…legged robots, prosthetic legs) (Merker et al, 2011), the intra-limb asymmetries in leg function are not well understood. In spite of a considerable number of studies on the potential effect of trunk posture on the human walkers whether as an imposed trunk posture (Grasso et al, 2000;Saha et al, 2008;Kluger et al, 2014), the natural inclination of the trunk (Leteneur et al, 2009(Leteneur et al, , 2013 or age-related flexed posture (McGibbon and Krebs, 2001;de Groot et al, 2014), little is known about the effects of trunk orientation on the axial leg function, specifically when trunk posture is varied across a wide range of angles in the sagittal plane.…”