Quick steps to reducing obesity and knee osteoarthritis

Walking with short, quick steps results in a small but significant increase in metabolic cost that may be beneficial for weight reduction or maintenance in obese persons and reduce the risk of knee osteoarthritis (OA), according to researchers at the Biomechanics and Energy Metabolism Laboratories, University of Massachusetts Amherst. Noting that obesity is the primary modifiable risk factor for knee OA, Russell and associates¹ attempted to develop a walking protocol for obese persons that requires more energy expenditure and supports weight loss but minimizes the biomechanical risk factors for knee OA.

Oxygen uptake was measured in 10 obese and 10 healthy-weight women while they walked on a treadmill at their preferred walking speed at a preferred stride length and a 15% shortened stride length (increased stride frequency). Peak impact shock, peak external knee adduction moment, and knee adduction angular impulse were measured during the 2 gait conditions.

Decreasing stride length 15% significantly increased metabolic cost by 4.6% and decreased the adduction angular impulse. However, it did not significantly affect the adduction moment or impact shock. The authors concluded that a 15% decrease in stride length is not sufficient to decrease the peak values of 2 of the biomechanical variables that may predispose obese women to knee OA but does elicit benefits over the course of a stride.

1. Russell EM, Braun B, Hamill J. Does stride length influence metabolic cost and biomechanical risk factors for knee osteoarthritis in obese women? Clin Biomech (Bristol, Avon). 2010 Mar 1; [Epub ahead of print].