Kinematic and Kinetic Gait Analysis to Quantify Locomotor Function in Pre-Clinical Models of the Rodent Hindlimb

The rodent hindlimb is a popular animal model for evaluating the effects of various musculoskeletal pathologies in a pre-clinical setting. Furthermore, rodent gait analyses have become a preferred strategy for identifying and quantifying the functional impacts of these pathologies. However, many of the currently utilized methods in rodent gait analysis are limited, providing only surface level insights into gait compensation strategies and pathologic movement function. In human motion analysis, joint kinematics and kinetics are the gold standard metric for evaluating movement function in both normal and pathologic populations, as they provide mechanistic insights into the underlying causes behind movement patterns. The ability to utilize these methods in rodent studies will elucidate specific functional deficits caused pathology and offer a more robust evaluative metric for quantifying the efficacy of proposed treatment strategies. Thus, the purpose of this thesis was to develop the necessary tools to measure 3-D joint kinematics and kinetics during rodent gait in order to provide a more comprehensive analysis of both healthy and pathologic rodent gait.

3-D motion capture and concurrent ground reaction force (GRF) data were collected on healthy Lewis rats during over-ground walking. This data was implemented into a custom musculoskeletal model of the rodent hindlimb to quantify 3-D joint kinematics and kinetics for normal rodent walking. The resulting normative dataset demonstrated significant variability in the rodents’ self-selected walking speeds, consistent with variability reported in the literature. A follow-up study was performed to investigate the effects of walking speed on gait parameters. Linear regression equations were presented, describing the relationships between walking speed and several kinematic, kinetic, and spatiotemporal gait parameters. Additionally, these relationships were used to develop a normalization scheme which minimizes variability in the presentation of kinematic and kinetic curves. Finally, the developed methodologies were utilized to evaluate functional impacts of two different hindlimb volumetric muscle loss injury models and quantify the treatment efficacy of a regenerative therapeutic. The results from this study demonstrated the usability of a motion capture and musculoskeletal modeling approach for providing detailed insights into injury response and recovery. This information can be leveraged into the development of treatment strategies focused on optimizing functional outcomes.