The effect of surface grades on the joint kinematics of quail during running

Heitmann, D.M.*; Scheunemann, T.L.; Carello, C.A.: The effect of surface grades on the joint kinematics of quail during running

Locomotion is a major component to most animals� daily energy budgets. Button Quail (Coturnix chinensis) are ground foragers and therefore spend a predominant amount of time walking and running. However, little is known about how surface grades and running speeds affect their stride parameters and joint kinematics. Stride parameters and joint kinematics are useful tools for evaluating how surface substrates affect the cost of locomotion because they reveal the relative time and range of motion devoted to deceleration and acceleration during each step. Deceleration occurs at the beginning of the step from when the foot strikes the ground until the middle of the stance. During this time potential energy can be stored in the elastic tendons and muscles. We quantified deceleration as the total amount of flexion at each joint. On the other hand, acceleration occurs at the end of the stance phase when the animal is pushing itself forward. This is the energetically expensive phase of the step. We quantified acceleration as the total amount of extension at each joint. We used a high speed digital camera to film Button Quail running on a motorized treadmill on a level surface, two inclines (10o and 20 o) and a decline (10 o). The Quail had markers on their lower limb joints for the purpose of digital analysis. We found that flexion at the ankle and knee joints decreased with increasing incline and that extension of the ankle, knee and hip joints increased with increasing incline. These results suggest that as animals run uphill there is an overall decrease in the potential for storing elastic energy in the tendons and muscles and that more energy must be devoted to the acceleration phase of the step.

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