Whole Body Coordination and Knee Movement Control During Five Rehabilitation Exercises

ABSTRACT

Knee rehabilitation exercises to improve motor control, target movement fluency, and displacement variability. Although knee movement in the frontal plane during exercise is routinely assessed in clinical practice, optimal knee control remains poorly understood. In this study, 29 healthy participants (height: 1.73 ± 0.11 m, mass: 73.5 ± 16.4 kg, age: 28.0 ± 6.9 years) performed 4 repetitions of 5 rehabilitation exercises while motion data were collected using the VICON PlugInGait full-body marker set. Fluency and displacement variability were calculated for multiple landmarks, including center of mass (CoM) and knee joint centers. Fluency was calculated as the inverse of the average number of times a landmark velocity in the frontal plane crossed zero. Variability was defined as the standard deviation of the frontal plane movement trajectories. CoM fluency and displacement variability were significantly different between tasks (p < .001). CoM displacement variability was consistently smallest compared to the constituent landmarks (p < .005). This was interpreted as a whole body strategy of compensatory variability constraining CoM frontal plane movement. Ipsilateral knee fluency (p < .01) and displacement variability (p < .001) differed substantially between tasks. The role of the weight-bearing knee seemed dependent on task constraints of the overall movement and balance, as well as constraints specific for knee joint stability.

Keywords:

• center of mass
• human
• interlimb coordination
• interlimb coordination
• stability

Acknowledgments

Kate Button and Paulien E. Roos were involved in data acquisition and processing. Kate Button provided substantial support with subject recruitment. Robert W. M. van Deursen performed all data analysis and prepared figures and tables for this paper. Robert W. M. van Deursen drafted the manuscript. All authors have been involved in revising the manuscript critically and have given final approval of the version to be published. The authors thank Dr. Rimmer and Miss Swar for their help with data collection and processing.

Funding

Paulien E. Roos was funded by a grant from Arthritis Research UK (Grant No. 18461).