A. Räisänen1, L. Benson1, J. Whittaker2,3,1,4, C. Emery1,4,5,6,7
1University of Calgary, Sport Injury Prevention Research Centre, Calgary, Canada, 2University of British Columbia, Department of Physical Therapy, Vancouver, Canada, 3Arthritis Research Canada, Vancouver, Canada, 4University of Calgary, McCaig Institute of Bone and Joint Health, Calgary, Canada, 5University of Calgary, Alberta Children’s Hospital Research Institute, Calgary, Canada, 6University of Calgary, Department of Community Health Sciences, Calgary, Canada, 7University of Calgary, Department of Pediatrics, Calgary, Canada
Background: Reduction of movement asymmetries is a key component of knee injury rehabilitation. Wearable accelerometers can be used to quantify accelerations of body segments during landing and could be a suitable tool for monitoring between-leg symmetry during rehabilitation.
Purpose: To assess the agreement between 1) ground reaction force (GRF)- and accelerometer-based center of mass (COM) acceleration and 2) GRF and tibial acceleration (TA) between-leg symmetry during countermovement jump (CMJ) and squat jump (SJ) landing in young adults.
Methods: Nineteen adults [11 females: 26.4 (±5.8) years, 167.0 (±3.5) cm, 70.8 (±13.1) kg; 8 males: 27.5 (±5.3) years, 178.0 (±8.6) cm, 78.7 (±10.5) kg] performed three CMJ and three SJ. Triaxial accelerometers were fastened to the anterior-medial aspect of both tibias and to the lower back near the COM. During the jumps, each foot landed on a separate force plate. The peak axial acceleration (g) during landing was identified from the individual force plates and each accelerometer. For both the GRF and TA data, symmetry was calculated as the difference between the leg peaks divided by the maximum peak and expressed as a percentage, with a positive value indicating a greater dominant leg peak. Mean symmetry was calculated across all trials for each participant. The agreement between the total GRF-based acceleration and the COM acceleration and between GRF- and TA-based lower limb symmetries was determined by intraclass correlation coefficient [ICC(3,2)] and Bland and Altman limits of agreement (±2 SD).
Results: The relative agreement [ICC(3,2)] between total GRF and COM acceleration was 0.83 (95% CI: 0.56, 0.94) for the CMJ and 0.88 (95% CI: 0.69, 0.95) for the SJ. The mean difference between total GRF and COM acceleration for the CMJ was 0.24 g (greater COM), with limits of agreement −1.34 to 1.82 g. The mean difference between total GRF and COM acceleration for the SJ was 0.38 g (greater COM), with limits of agreement −1.15 to 1.91 g. The relative agreement [ICC(3,2)] between GRF- and TA-based lower limb symmetry was 0.84 (95% CI: 0.59, 0.94) for the CMJ and 0.52 (95% CI: -0.23, 0.82) for the SJ. The mean difference between the GRF- and TA-based lower limb symmetries for the CMJ was −6% (greater GRF-based asymmetry), with limits of agreement -32 to 19%. The mean difference between the GRF- and TA-based lower limb symmetries for the SJ was 0%, with limits of agreement −45 to 45%.
Conclusion(s): Both the relative and absolute agreement between the GRF and COM acceleration are acceptable. The large limits of agreement between the GRF- and TA-based lower limb symmetries is likely due to shock attenuation happening proximal to the tibias in the knee and hip joints.
Implications: Our findings indicate that a wearable technology solution is a valid tool for quantifying landing parameters at the COM but inter-limb symmetry evaluated at the tibia is different than symmetry based on COM accelerations. Further research is needed to identify the appropriate solutions for measuring symmetries in the clinical setting.
Funding, acknowledgements: This research was supported through Canadian Institutes of Health Research Foundation Program and the Vi Riddell Pediatric Rehabilitation Research Program.
Keywords: tibial acceleration, ground reaction force, IMU
Topic: Musculoskeletal: lower limb
Did this work require ethics approval? Yes
Institution: University of Calgary
Committee: Conjoint Health Research Ethics Board
Ethics number: REB18-1162, REB19-0276
All authors, affiliations and abstracts have been published as submitted.
