Slower walking speed in the elderly may be explained by loss of muscle strength and mass

Research recently published in The Journal of Physiology has found that elderly people walk at a slower speed and tire more quickly because of loss of strength and mass in leg muscles. Using computer simulations they found that these physiological changes explain the slower walking speed preferred by the elderly, and that a focus on building up these leg muscles may be the only effective way to improve elderly walking.

Walking performance, measured in terms of energy efficiency - i.e. how far one can travel per calorie consumption - and walking speed, has been shown to decline as get older. The reason for this decline is unknown as ageing produces a range of physiological changes which affect gait (a person's manner of walking), but are hard to study individually.

This decline in walking performance can lead to a less active lifestyle worsening the health of and is directly linked to a lower 10-year survival rate for people at age 75 (1). The findings of this study suggest that a focus on building up muscles in the legs may be the only effective way to improve elderly walking. In other words, improving other features such as joint flexibility or walking strategy would not help normal elderly people to walk better.

The research conducted at Carnegie Mellon University used computer simulations to generate physiologically and physically plausible walking behaviors in order to predict how physiological changes affect gait. The computer model consisted of a musculoskeletal system, which was designed based on human physiology, and a neural controller, which drives the musculoskeletal system to generate behaviors and has demonstrated a state-of-the-art prediction level in previous works (2,3). The physiological causes of the declined walking performance were searched by selectively 'ageing' the neuro-musculo-skeletal properties of the model (for example, changes in body mass distribution, a range of joint motions, and neural transmission delay and noise), and only the aging in muscle properties resulted in a in walking .

Given that this was a simulation study the results are based on assumptions that may limit its predictive capabilities as it simplifies the human locomotor system and relies on a hypothesized neural control circuitry.

Seungmoon Song, the first author of the study said, "In the long term, we plan to extend the predictive capability of our neuromechanical framework, for example, to analyze pathological gaits after stroke or spinal cord injury and to prescribe optimal treatment."


Explore further

Impact of inactivity on muscles more severe for older people

More information: Journal of Physiology (2018). DOI: 10.1113/JP275166

(1) Gait Speed and Survival in Older Adults: jamanetwork.com/journals/jama/fullarticle/644554

(2) A neural circuitry that emphasizes spinal feedback generates diverse behaviours of human locomotion: onlinelibrary.wiley.com/doi/10.1113/JP270228/full

(3) Evaluation of a Neuromechanical Walking Control Model Using Disturbance Experiments: www.frontiersin.org/articles/1 … ncom.2017.00015/full

Journal information: Journal of Physiology

Citation: Slower walking speed in the elderly may be explained by loss of muscle strength and mass (2018, January 17) retrieved 22 April 2019 from https://medicalxpress.com/news/2018-01-slower-elderly-loss-muscle-strength.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
19 shares

Feedback to editors

User comments

Jan 18, 2018
Please consider weakened joints that no longer are able to withstand the forces of stronger muscles. Then the muscles get reduced in strength to lessen damage to joints.

Jan 20, 2018
Pretend YOU are elderly. ( Put yourself in their walking shoes. ) Tie a simple hobble which will permit YOU no more than a 10" stride. Try walking as fast as possible on a smooth surface, - take notes. Next walk as SLOWLY as possible, and let a number of assistants ( in series ) perturb you balance at different points in stride. Make sure someone can catch YOU. It should quickly become apparent a markedly shortened stride ( as if You were suffering hamstring hyper tonus ) makes it near impossible to regain YOUR interrupted balance. A shortened stride - due to hamstring muscle spindle cells firing 24/7 results in RSI and the muscle no longer able to fully relax and provide a normal length of stride. Now imagine YOU are elderly - fear will make you even more tentative. A short stride will put anyone at risk of falls on dry level ground - much less compromised terrain.

Jan 20, 2018
Muscle strength is important. I would submit in ways not examined in the research.

Jan 20, 2018
Joints may suffer damage by means of typical joint disease, - but some damage is likely the result of unbalanced muscle groups that result in abnormal vector forces which load joints in directions that may result in damage independent of joint disease.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more