Aging, motor skill, and the energy cost of walking: implications for the prevention and treatment of mobility decline in older persons

Abstract

Background: Age-associated neural changes profoundly affect the biomechanics and energetics of walking, increase energy cost, and require novel approaches to exercise that focus on motor learning theory.

Methods: We present a conceptual framework for motor skill in walking, its effect on the energy cost of walking, and the influence of the aging brain.

Results: Motor learning theory and practice can be incorporated into interventions to promote skilled, energy efficient walking in older people.

Conclusions: An extensive literature on motor skill and motor learning, derived from neuroscience, sports medicine, and neurorehabilitation, can be applied to problems of walking in late life.

Keywords: Brain aging; Energy cost of walking; Gait.; Motor control.

Figure 1.

Shifts in the J-curve of the energy cost–speed relation. Within an individual, the preferred gait speed relates to the lowest energy. More abnormal gait shifts the J-curve relation upward and to the left, but for the abnormal gait, the energy cost of walking remains lowest at a preferred gait speed. Within each “J-curve,” those with the greatest hip extension abnormality tend to have the highest energy cost and walk at gait speeds below or above preferred speed. Visual approximates of J-curves for energy cost-speed relations among older adults with abnormal gait who walked: very slow, dotted line; moderately slow, solid line; and slow, dashed line.

Figure 2.

Energy cost of gait abnormalities. The greater the biomechanical abnormality of hip extension, trunk flexion and foot-floor angle, the greater the energy cost of walking.

Figure 3.

Brain and walking performance: response to challenges. The brain responds to the age-related changes to fix walking performance. Both compensation (use of greater body capacities) and adapt/restore (learn strategies to optimize capacities) can result in good walking performance. Compensation differs from restoration in the both the resources used (effort) and the feedback provided to the brain.