The effect of the engineering properties of treadmill surfaces on the performance of athletes in a sub-maximal test

Abstract

This study compares the physiological responses and rating of perceived exertion (RPE) of subjects exercising on two different treadmills. Eleven physically active subjects, all familiar with treadmill running, were tested on both a Woodway and a Powerjog treadmill in a submaximal test. Although the Powerjog ran at actual speeds slightly higher (P < 0.05) than the Woodway at each of two target speeds, paired comparisons in terms of V O 2 , heart rate and RPE were adjusted by regressing the differences of each of these response variables in turn on the actual difference in treadmill speed for the particular individual. At a target speed of 4.00 m s A1 , the Woodway produced signi®cantly higher average V O 2 , heart rate and RPE. A similar trend existed at the lower target speed of 3.11 m s A1 , but did not quite achieve statistical signi®cance (P < 0.05). These physiological differences are attributed to the structural design of the treadmills, the key feature most likely being the stiffness of the running surface. Measurements of the de¯ection of the running surface, under static loads up to three times human bodyweight, showed that the Woodway was signi®cantly stiffer than the Powerjog. The results do not, of course, imply that one treadmill is`better' overall than the other, but they are signi®cant for manufacturers and athletes since comparisons of performance measured on different treadmills in different laboratories may be spurious.

The modelling and performance of training shoe cushioning systems

“…No significant differences were found for any variable. This cannot be attributed to a difference in the regularly calibrated treadmill velocity and was contrary to expectations based on previously reported tests ( Grant et al . 1998 ).…”

“…Since this cannot be predicted by FEA, the physiological response of a sample of subjects must be measured. Sub‐maximal treadmill tests ( Grant et al . 1998 ) are then appropriate.…”

“…Its detailed analysis is, however, more appropriately addressed in the biomechanics, rather than sports engineering, literature since, although it can be in¯uenced to a limited extent by the so-called motion control' features of some trainers, runners' individual gaits are largely outwith the control of the product designer. Grant et al (1998) have demonstrated that, for the same running speed, a more-compliant treadmill surface results in a signi®cantly lower oxygen (Borg 1982). It might then be expected that trainers with more cushioning would show a similar bene®cial effect.…”

“…Grant et al . (1998 ) have demonstrated that, for the same running speed, a more‐compliant treadmill surface results in a significantly lower oxygen uptake ( V · O 2 ), lower heart rate ( HR ) and reduced rating of perceived exertion (RPE) ( Borg 1982).…”

“…In their seminal paper, McMahon & Greene (1979) used a more complex 2-mass, 2-spring model to infer the effect of running surface compliance on running economy. Such a lumped-parameter model can be extended to include the nonlinear, compression-stiffening material response that is characteristic of trainers (Walker 1998) and of some running surfaces (Grant et al 1998), but a continuum approach, such as ®nite element analysis (FEA), offers greater scope for the analysis of novel designs with increasingly complex geometric features. However, before attempting an FEA of shoe deformation under actual service conditions, it is necessary to identify a suitable constitutive model for the materials involved and to determine the appropriate engineering constants, benchmarked against repeatable laboratory tests.…”