Emulating constant acceleration locomotion mechanics on a treadmill

JOURNAL OF BIOMECHANICS

卷:49

Article

Farris, Dominic James^1,2 

[1] Univ Queensland, Sch Human Movement & Nutr Sci, Bldg 26B,Blair Dr, Brisbane, Qld 4072, Australia

[2] Australian Inst Sport, Movement Sci, Canberra, ACT, Australia

关键词: Mechanical work;    Impulse;    Walking;    Running;    Gait;    Force;   

DOI  :  10.1016/j.jbiomech.2016.01.030

来源: Elsevier

【 摘 要 】

Locomotion on an accelerating treadmill belt is not dynamically similar to overground acceleration. The purpose of this study was to test if providing an external force to compensate for inertial forces during locomotion on an accelerating treadmill belt could induce locomotor dynamics similar to real accelerations. Nine males (mean +/- sd age = 26 +/- 4 years, mass = 81 +/- 9 kg, height = 1.8 +/- 0.05 m) began walking and transitioned to running on an accelerating instrumented treadmill belt at three accelerations (0.27 m s(-2), 0.42 m s(-2), 0.76 m s(-2)). Half the trials were typical treadmill locomotion (TT) and half were emulated acceleration (EA), where elastic tubing harnessed to the participant provided a horizontal force equal to mass multiplied by acceleration. Net mechanical work (W-COM) and ground reaction force impulses (I-GRF) were calculated for individual steps and a linear regression was performed with these experimental measures as independent variables and theoretically derived values of work and impulse as predictor variables. For EA, linear fits were significant for W-COM (y = 1.19x + 10.5, P < 0.001, R-2 = 0.41) and I-GRF (y = 0.95x + 8.1, P < 0.001, R-2 = 0.3). For TT, linear fits were not significant and explained virtually no variance for W-COM (y = 0.06x + 1.6, P = 0.29, R-2 < 0.01) and I-GRF (y = 0.10x + 0.4, P = 0.06, R-2 = 0.01). This suggested that the EA condition was a better representation of real acceleration dynamics than TT. Running steps from EA where work and impulse closely matched theoretical values showed similar adaptations to increasing acceleration as have been previously observed overground (forward reorientation of GRF vector without an increase in magnitude or change in spatio-temporal metrics). (C) 2016 Elsevier Ltd. All rights reserved.

【 授权许可】

Free