A Proposed Method to Assess the Mechanical Properties of Treadmill Surfaces.

Enrique Colino,Bas Van Hooren,Kenneth Meijer,Alejandro Lucia,Jose Luis Felipe,Jorge Garcia-Unanue,Leonor Gallardo

doi:10.3390/s20092724

Abstract

The aim of this study was to define a reliable and sensitive test method for assessing Shock Absorption (SA), Vertical Deformation (VD), and Energy Restitution (ER) in treadmill surfaces. A total of 42 treadmills belonging to four different models were included in the study: (a) Technogym Jog700 Excite (n = 10), (b) Technogym Artis Run (n = 12), (c) LifeFitness Integrity Series 97T (n = 11), and (d) LifeFitness Integrity Series DX (n = 9). An advanced artificial athlete (AAA) device was used to assess SA, VD, and ER at three different locations along the longitudinal axis of each treadmill and in the support area of the athletes’ feet. For each location, our results show that the error assumed when performing one impact with the AAA instead of three (SA ≤ |0.1|%, VD ≤ |0.0| mm, and ER ≤ |0.2|%) is lower than the smallest changes that can be detected by the measuring device (SA = 0.4%, VD = 0.2 mm, and ER = 0.9%). Also, our results show the ability of the test method to detect meaningful differences between locations once the one-impact criterium is adopted, since absolute minimum differences between zones (SA: |0.6|%, VD: |0.3| mm, and ER: |1.2|%) were above the uncertainty of the measuring device. Therefore, performing a single impact with the AAA in each of the three locations described in this study can be considered a representative and reliable method for assessing SA, VD, and ER in treadmill surfaces.

Highlights

It is has been known for decades that running mechanics can be affected by the ground surface characteristics [1]
An old (>7 years) and a new (
When comparing these values with the allowed ranges set by the IAAF regulation for running track surfaces [13] (i.e., 35%–50% for Shock Absorption (SA), 0.6–2.5 mm for Vertical Deformation (VD) and non-available for Energy Restitution (ER)), our results show that even the stiffest treadmill doubles the maximum VD allowed for athletics track surfaces, and yields higher and lower values of SA and ER, respectively

Summary

Introduction

It is has been known for decades that running mechanics can be affected by the ground surface characteristics [1]. Surface compliance is a potential determinant of the energetic cost of running and of running performance, as well as of injury risk [3,4,5]. Compliant surfaces deform during the footfall while running, thereby allowing energy to be transferred from the athlete to the ground, with part of this energy being returned back to the athlete during the subsequent propelling phase. The amount of energy stored by the surface—and, the energy potentially returned to the athlete—increases with compliance [6]. Compliance itself does not fully represent the dynamic behavior of the surface.

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Discussion

Conclusion