Subject Area
Biophysics, Health Sciences, Physical Sciences, Physics, Physiology, Biological Sciences, General
Abstract
Sprint running accelerations require runners to apply surface forces that: support body weight by pushing downward, accelerate the body horizontally by pushing backward, and align the direction of the push with the body’s mass center to maintain balance and posture, which imposes an upper limit on the average forward acceleration force equal to the average gravitational force (1.0 G) acting on the runner. This expectation arises from the mechanical constraints imposed by the need to generate sufficient vertical force to support body weight against gravity while simultaneously producing horizontal force to accelerate forward and aligning the push through the center of mass for balance. We tested the 1.0 G hypothesis by acquiring single-second sprint-start data from humans and canine sprinters in competition or equivalent (n=4 each). Additionally, we evaluated single-push data from human sprinters using force-instrumented (n=28) or platform-mounted (n=25) starting blocks against a condition-specific, single-push theorized limit of 1.25 G. The overall single-second race-start acceleration means of the human and canine sprint group (6.79±0.87 m•s-2, n=8) were significantly less than the theorized maximum of 9.81 m•s-2. Quadrupeds demonstrated a higher mean acceleration compared to bipeds (7.4±0.39 vs. 6.16±0.39 m•s-2). The single-push, mass-specific horizontal force maximums measured for human sprint athletes (0.99±0.06 G) also did not exceed the theorized gravitational limit. These results support our hypothesis that sprint acceleration maximums are imposed by gravitational forces and indicate that quadrupeds operate closer to this earthly limit than bipeds.
Degree Date
Summer 8-6-2024
Document Type
Dissertation
Degree Name
Ph.D.
Department
Applied Physiology and Wellness
Advisor
Peter G. Weyand
Second Advisor
Eric G. Bing
Format
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License
Recommended Citation
Brooks, Lance, "Maximizing Legged Accelerations: A Matter of Force, Time, and Gravity" (2024). Applied Physiology and Wellness Theses and Dissertations. 2.
https://scholar.smu.edu/simmons_dapw_etds/2
