A Proposed Method to Assess the Mechanical Properties of Treadmill Surfaces

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.

Mechanical Properties of Treadmill Surfaces Compared to Other Overground Sport Surfaces

“…For that, we performed three repetitions of the drop test at each test location, with intervals of 30 ± 5 s. We discarded the results of the first test and calculated the mechanical properties of each location as the mean values of the second and third tests. The treadmills were assessed at three points as described elsewhere [26], performing only one drop test per location. For each surface included in the study, we calculated the SA, VD, and ER as the mean values of all the test locations.…”

Sprint performance and force-velocity profiling does not differ between artificial turf and concrete

“…5 Compliant surfaces deform during the ground contact of sprinting, 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 propulsive phase. 7 The amount of energy stored by the surface increases with compliance, 8 while the amount of energy returned depends on the spring stiffness/viscosity of the surface. 9 The spring stiffness is typically assessed by determining the energy restitution and has been reported to be >90% in concrete and 39-44% in artificial turf.…”