Thursday, October 22, 2015 Small Study Finds Varied Walking Speed Burns More Calories Than Steady Pace The value of interval training and changing up routines has been substantiated for more demanding exercise programs, so why couldn't the concept also apply to simply walking? It does, say researchers, who also found that an individual's naturally "preferred" walking speed varies depending on how far he or she has to walk. According to a small-scale study published in the September issue of Biology Letters (pdf), walking at varying speeds requires a 6% to 20% higher metabolic cost than walking at a constant rate, and the acts of starting and stopping alone could account for between 4% and 8% of the caloric costs of a walking episode. They assert that those starts, stops, and fluctuations aren't always considered when calculating the caloric burn associated with walking. The findings are based on research involving 16 healthy young adults (average age—23) who were asked to walk on a treadmill set to a constant speed, and then instructed to increase or decrease their pace—to walk toward the front or allow themselves to slow to the back of the treadmill—at varying intervals. Researchers used 2 models to evaluate energy consumption—one based on kinetic energy fluctuations and the other the inverted pendulum model—and were able to identify metabolic rate increases through both. In a second part of their investigation, researchers instructed 10 participants to each walk 10 distances—.5, 1, 2, 4, 6, 8, 10, 12, 14, and 89 meters—at a "comfortable" speed to find out if an individual's preferred rate varied depending on the walking distance required. The answer: it does, with participants tending to walk more slowly over shorter distances, and speeding things up when tasked with a longer walk. Researchers believe that the results of the study may help inform rehabilitation professionals as they assess patients and clients. "Rehabilitation walking speeds are used to quantify mobility and rehabilitation, so bout distances should be chosen to avoid artificially lowering speeds," authors write. As for the findings related to metabolic cost, they write that "using the cost of changing speeds may improve daily activity tracking, energy balance estimates for obesity, and metabolic estimates during sports." Research-related stories featured in PT in Motion News are intended to highlight a topic of interest only and do not constitute an endorsement by APTA. For synthesized research and evidence-based practice information, visit the association's PTNow website.