No abstract

Backward running has long been used in sports conditioning programs and has recently been incorporated into rehabilitative setting as a method of increasing quadriceps strength while decreasing the joint compressive forces about the knee. Although backward locomotion has been studied kinetically, the metabolic cost of backward walking or and/or running has not to my knowledge been previously characterized. O 2 consumption and other cardiopulmonary variables were measured under constant speed exercise during backward and forward walking at 107. 2m min-1 and during backward and forward running at 160.8m min-1 peak O 2 consumption (VO 2 peak) was also measured during maximal incremental backward and forward running VO 2 , HR and blood lactate were significantly higher P< 0.001) during backward walking and running than during forward walking and running. During backward walking, and backward running, subjects exercised at 60% and 84% of their forward VO 2 peak, respectively. In conclusion, for a given speed, backward locomotion elicits a greater metabolic demand and cardiopulmonary response than forward locomotion. In general, these data suggest that while undergoing rehabilitation an injured athlete may continue to exercise using backward walking/running at an intensity sufficient enough to maintain cardiovascular fitness levels.

Clinical exercise testing is increasingly being utilized in clinical practice because of the valuable, often unique information that it provides in patient diagnosis and management. This is also due to a growing awareness that resting cardiopulmonary measurements provide an unreliable estimate of functional capacity. A continuum of exercise testing modalities for functional evaluation from "low tech" to "high tech" will be discussed. These include the six minute walk test, shuttle walk test, exercise induced bronchoconstriction test, cardiac stress test, and cardiopulmonary exercise testing. The main focus of this article will be cardiopulmonary exercise testing including indications, important measurements, salient methodological considerations, and interpretation.