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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: Inter-limb symmetry in functional tasks is an important goal of knee injury rehabilitation and should be achieved through improvements in the injured limb and not by reduced function in the contralateral limb. Methods for monitoring both limbs in a clinical setting are needed.
Purpose: The primary aims of this study were to: 1) compare tibial accelerations (TA) of previously injured and contralateral limbs in individuals with history of a youth sport-related intra-articular knee injury (10±3 years previous) to TAs in uninjured controls, and 2) compare inter-limb asymmetry of previously injured participants to uninjured controls during two bilateral jumping tasks.
Methods: Nineteen adults [11 females, 8 males; mean 26.8 (SD 5.5) years; 171.6 (8.2) cm; 74.1 (12.4) kg; dominant leg: 18 right, 1 left] with no history of knee injury (uninjured group) and twenty-four adults [14 females, 10 males; 26.8 (2.9) years; 173.0 (9.6) cm; 82.3 (14.1) kg; dominant leg: 24 right; injured leg: 19 right, 5 left] with history of intra-articular knee injury (injured group) were recruited. Participants performed three countermovement jumps (CMJ) and three squat jumps (SJ). The peak landing axial acceleration (g) was identified from triaxial accelerometers fastened to the anterior-medial aspect of each tibia. The mean TA was calculated for both limbs and compared between groups. Inter-limb asymmetry was calculated as the difference in peak TA between legs divided by the maximum peak and expressed as a percentage, with positive values indicating greater dominant (uninjured participants) or contralateral (injured participants) leg peak. Mean asymmetry was calculated across all trials for each participant. The range of TA and TA asymmetry among the injured group was compared descriptively to the range of TA and TA asymmetry among the uninjured group through box plots.
Results: For the uninjured participants, the peak TA ranged from 4.3 to 8.2 g with outliers identified at 9.8 g and 10.2 g (CMJ) and from 3.4 to 10.2 g (SJ). For the injured participants, the injured leg TA range was from 2.6 to 10.1 g and 4.2 to 9.1 g for the CMJ and SJ, respectively. On the contralateral leg, the TA range was from 4.2 to 10.8 g and 4.3 to 9.4 g for the CMJ and SJ, respectively. Lower limb asymmetries for uninjured participants ranged from -39% to 27% (CMJ) and from -23% to 34% (SJ). For the injured participants, the range of lower limb asymmetries, excluding outliers, was from -14% to 16% (CMJ) and from -17% to 20% (SJ), with outliers identified at 53% for the CMJ and at 32% for the SJ.
Conclusion(s): Most adults with history of youth sport-related knee injury demonstrate symmetrical landing patterns for the CMJ and SJ. In the CMJ, one asymmetry value in a previously injured participant was outside of the range of the uninjured controls, suggesting that CMJ could be used to identify asymmetrical landing patterns.
Implications: TA may be used to identify individuals with asymmetrical landing patterns in the countermovement jump even 10 years following youth sport-related intra-articular knee injury.
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, athletic injuries, 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.
