The Relationship Between Walking Speed and the Energetic Cost of Walking in Persons With Multiple Sclerosis and Healthy Controls: A Systematic Review

Abstract

Background Persons with multiple sclerosis (pwMS) experience walking impairments, characterized by decreased walking speeds. In healthy subjects, the self-selected walking speed is the energetically most optimal. In pwMS, the energetically most optimal walking speed remains underexposed. Therefore, this review aimed to determine the relationship between walking speed and energetic cost of walking (Cw) in pwMS, compared with healthy subjects, thereby assessing the walking speed with the lowest energetic cost. As it is unclear whether the Cw in pwMS differs between overground and treadmill walking, as reported in healthy subjects, a second review aim was to compare both conditions. Method PubMed and Web of Science were systematically searched. Studies assessing pwMS, reporting walking speed (converted to meters per second), and reporting oxygen consumption were included. Study quality was assessed with a modified National Heart, Lung and Blood Institute checklist. The relationship between Cw and walking speed was calculated with a second-order polynomial function and compared between groups and conditions. Results Twenty-nine studies were included (n = 1535 pwMS) of which 8 included healthy subjects (n = 179 healthy subjects). PwMS showed a similar energetically most optimal walking speed of 1.44 m/s with a Cw of 0.16, compared with 0.14 mL O2/kg/m in healthy subjects. The most optimal walking speed in treadmill was 1.48 m/s, compared with 1.28 m/s in overground walking with a similar Cw. Conclusion Overall, the Cw is elevated in pwMS but with a similar energetically most optimal walking speed, compared with healthy subjects. Treadmill walking showed a similar most optimal Cw but a higher speed, compared with overground walking.

The increased perceived exertion during the six minute walking test is not accompanied by changes in cost of walking, gait characteristics or muscle fatigue in persons with multiple sclerosis

“…Accepting previous evidence on the energetically optimal speed, it can be suggested that the subjects in our study also walked below their energetically optimal speed. (Theunissen et al, 2021) While walking speed increased during the 6MWT, the Cw was expected to decrease. It should however be noted that the individual Cw curves are not the scope of this study and that our subjects were asked to walk at a maximal speed.…”

“…Persons with MS walk at a greater Cw compared to healthy persons (Stella et al, 2020) but with a similar optimal speed, as described by the U-shaped relationship between walking speed and the Cw. (Theunissen et al, 2021) Since walking is energetically more demanding in pwMS, an increased Cw might be accompanied by changes in gait parameters. Evaluating this simultaneously will contribute to the understanding of both physical and perceived fatigue.…”

Metabolic costs of walking and arm reaching in persons with mild multiple sclerosis

“…However, whether the benefits of exercise restore locomotory performance to levels comparable to control individuals is uncertain. Regardless of the exact mechanism, the slower gait speeds in pwMS could be explained in-part by the increase in metabolic effort as speed is reduced to minimize costs (36, 74).…”

“…Both preferred walking and reaching speeds are often selected to minimize the cost of transport (J kg −1 m −1 ) of the movement (33, 47, 71). Recent evidence suggests that pwMS minimize walking cost of transport when selecting preferred speeds (45, 74), but that the costs tend to be more expensive than controls. Measuring preferred walking and reaching speeds in this study would have also revealed whether our cohort of pwMS were selecting slower speeds than our HCs.…”

Multimodal Agility-Based Exercise Training for Persons With Multiple Sclerosis: A New Framework

“…53 Another worthwhile measure would be the energetic cost of walking, which is based on oxygen consumption during walking. 54 Several studies have recently described associations of sensor-based outcomes during gait trials with perceived state fatigability (ratings of fatigue while performing a task), 55 objective motor fatigability (deterioration of objective performance during a motor task), 52 and trait fatigue (self-report of fatigue experienced over a longer time-period (eg, several weeks)). 12,52 Sensor-based and fatigue-related outcomes of intervention studies applying MAT should be compared to more traditional, unimodal types of exercise (ie, aerobic, or resistance exercise) to confirm that incorporating more sensory and cognitive stimuli is superior in affecting these outcomes, and potentially superior as a reserve-building activity.…”