In that impaired walking performance is a key predictor of death among older adults, a greater metabolic cost (worse economy) as compared to younger counterparts is a defining characteristic. Justus Ortega, from Humboldt State University (California, USA), and colleagues enrolled 15 men and women (average age 69 years) to walk for 30 minutes or more, three times weekly; and 15 men and women (average age 69 years) to run on a treadmill at three speeds (0.75, 1.25, and 1.75 m/s), for 30 minutes or more, three times weekly. The team determined walking economy using expired gas analysis and walking mechanics via ground reaction force. Older runners had a 7-10% better walking economy than older walkers over the range of speeds tested, and had walking economy similar to young sedentary adults over a similar range of speeds. In contrast to older runners, older walkers had similar walking economy as older sedentary adults and about 26% worse walking economy than young adults. The study authors conclude that: “Running mitigates the age-related deterioration of walking economy whereas walking for exercise appears to have minimal effect on the age-related deterioration in walking economy.”
