SOFT TISSUE MOTION AND ITS EFFECTS ON HUMAN LOCOMOTION DYNAMICS
Open Access
- Author:
- Masters, Samuel Edward
- Graduate Program:
- Kinesiology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- July 27, 2020
- Committee Members:
- John Henry Challis, Dissertation Advisor/Co-Advisor
John Henry Challis, Committee Chair/Co-Chair
Robert Barry Eckhardt, Committee Member
Jonas Rubenson, Committee Member
Henry Joseph Sommer, III, Outside Member
Jonathan Bates Dingwell, Program Head/Chair - Keywords:
- Biomechanics
Running
Walking
Joint Kinetics
Joint Moments
Soft Tissue Motion
Stability - Abstract:
- The majority of models of the human musculoskeletal system assume the body segments are rigid and therefore does not account for the intra-segment soft tissue motion, despite the human body being primarily comprised of soft tissue. Intra-segment forces arise as a consequence of the motion of the soft tissue of a segment relative to the bone(s) of the segment. These forces may have important implications for analyses in biomechanics. There is evidence that suggests soft tissue motion has profound effects on the dynamics of human movement, however the extent to which soft tissue motion influences locomotion dynamics and joint kinetics has not been fully explored. The overarching purpose of this dissertation was to examine the influence of soft tissue motion (wobbling) during human movement. Three models that explicitly account for soft tissue motion and its energetic consequences were developed. Study one developed a model of walking, and study two developed a model of running. Each of these models were minimalistic, with two variants one with and another without wobbling components. Simulations with these models allowed for the investigation of the effects of soft tissue motion on the dynamic stability of gait. For study three, a model with and without a wobbling component was used to assess the effects of soft tissue motion on the joint dynamics during the stance phase of running. The key finding of study one and study two was that a damped wobbling mass increased the stability of walking and running. The key findings of study three was that the wobbling component had little effect on the knee joint kinetics, but large effects on the hip joint kinetics. The timings of the peak hip joint moments and powers differed by up to 15 percent between the rigid body model and the model with wobbling masses. The greatest effect occurred for the calculated hip joint power, where the peak magnitude of the hip joint power increased by over 50% for the wobbling mass model. Many current approaches for analyzing human movement which lump the bone and surrounding soft tissues for a segment into a single rigid model component fail to capture the important effects of soft tissue motion. Collectively the findings of the three studies provide new evidence that soft tissue motion plays a large role in the stability of human locomotion, and influences the dynamics of locomotion in particular this soft tissue motion effects the resultant joint dynamics during running.