Age-Related Adaptations of Lower Limb Intersegmental Coordination During Walking

Abstract

Lower-limb intersegmental coordination is a complex component of human walking. Aging may result in impairments of motor control and coordination contributing to the decline in mobility inducing loss of autonomy. Investigating intersegmental coordination could therefore provide insights into age-related changes in neuromuscular control of gait. However, it is unknown whether the age-related declines in gait performance relates to intersegmental coordination. The aim of this study was to evaluate the impact of aging on the coordination of lower limb kinematics and kinetics during walking at a conformable speed. We then assessed the body kinematics and kinetics from gait analyses of 84 volunteers from 25 to 85 years old when walking was performed at their self-selected speeds. Principal Component Analysis (PCA) was used to assess lower-limb intersegmental coordination and to evaluate the planar covariation of the Shank-Thigh and Foot-Shank segments. Ankle and knee stiffness were also estimated. Age-related effects on planar covariation parameters was evaluated using multiple linear regressions (i.e., without a priori age group determination) adjusted to normalized self-selected gait velocity. Colinearity between parameters was assessed using a variation inflation factor (VIF) and those with a VIF < 5 were entered in the analysis. Normalized gait velocity significantly decreased with aging ( r = −0.24; P = 0.028). Planar covariation of inter-segmental coordination was consistent across age (99.3 ± 0.24% of explained variance of PCA). Significant relationships were found between age and intersegmental foot-shank coordination, range of motion of the ankle, maximal power of the knee, and the ankle. Lower-limb coordination was modified with age, particularly the coordination between foot, and shank. Such modifications may influence the ankle motion and thus, ankle power. This observation may explain the decrease in the ankle plantar flexor strength mainly reported in the literature. We therefore hypothesize that this modification of coordination constitutes a neuromuscular adaptation of gait control accompanying a loss of ankle strength and amplitude by increasing the knee power in order to maintain gait efficiency. We propose that foot-shank coordination might represent a valid outcome measure to estimate the efficacy of rehabilitative strategies and to evaluate their efficiency in restoring lower-limb synergies during walking.

Age-related changes in the neuromuscular control of forward and backward locomotion

“…To date, several studies have dealt with the effects of aging on forward walking. Our results are aligned with prior results showing that older subjects take shorter steps [ 77 ] ( Fig 1 ) and adapt their intersegmental coordination mainly by changing the amplitude and phase of shank and foot motion [ 1 , 13 , 21 , 22 ] ( Fig 2A ). Most authors of previous work discuss a reduction in mechanical power generated by the plantarflexor muscles as the hallmark biomechanical features of older gait.…”

“…The modifications of walking between young and older adults occur in parallel with, amongst other factors, changes in the musculoskeletal system [ 7 , 8 ] as well as the central and peripheral nervous systems [ 9 , 10 ]. A number of studies have provided new insights about the plasticity of the neuromuscular control of gait to adapt to those age-related physiological changes (e.g., [ 11 – 13 ]).…”

“…The decline of propulsive power generation during push-off is thus not only due to a reduced muscular capacity but might also emerge from a different neuromuscular control strategy [ 19 ]. Therefore, recent efforts have been made to understand the age-related plasticity of the neuromuscular system during forward walking [ 1 , 13 , 21 – 23 ]. For example, using the planar covariation law [ 24 , 25 ], significant adjustments of the intersegmental coordination related to aging, and especially of the shank-foot coordination, have been documented.…”

“…Altered spatiotemporal stride parameters [ 2 , 31 ], altered coordination patterns among the elevation angles of the lower limb segments [ 1 , 13 ], and wider bursts of muscle activity [ 28 , 29 ] have been previously documented for the forward locomotion of older adults. Here, we expected that some of these alterations might apply also to backward walking.…”

Risk factors leading to glaucoma surgery of glaucoma patient using Japanese nationwide administrative claims data: A retrospective non-interventional cohort study

“…A VIF exceeding 10 was regarded as indicating serious multicollinearity, and values greater than 4.0 was considered a cause for concern. [27][28][29] P -values, adjusted odds ratios (ORs) and Wald 95% con dence intervals (CIs) were obtained for the predictor variables. Furthermore, strati ed analysis by CS were also performed.…”