DOS 2020

DOS Kongressen 2020 · 57 Reliability of a new measure of landing stability Jesper Bencke, Mette Kreutzfeldt Zebis Department of Orthopaedic Surgery, Copenhagen University Hospital; Department of Midwifery, Physiotherapy, Occupational Therapy and Psychomotor Therapy Physiotherapy, University College Copenhagen Background: Standing postural control has often been used as a measure of stability and a potential indicator of lower limb injury risk. Yet, acute injuries like ankle sprains happen within the first few milliseconds after contact, and dynam- ic landing tests might have a better potential for injury risk after rehabilitation. Purpose / Aim of Study: To examine the reliability of a new parameter of landing stability in a group of young recreational athletes. Materials and Methods: 11 subjects (3 female) volunteered to participate and were tested twice, one week apart. The subjects were instructed to jump a distance equal to 100% of leg length and land on a force plate as stable as possible and remain still for 5 seconds. The resultant centre of pressure (CoP) was measured at 200 Hz, and the distance of CoP translation was calculated in epochs of 200 ms during the first second. The average of 3 landings on the preferred jump leg was calculated. The Student t-test for paired samples was used to identify systematic error in the test- retest measurements (p < 0.05). Intraclass Correlation Coefficient (ICC3,k) was determined for relative reliability, while Coefficients of Variance (CV) were determined for absolute reliability. Findings / Results: The distance of the CoP was highest during the initial 200 ms and rapidly declined and levelled during the last 400 ms. No differences from test to retest was found in any time epoch. The reliability was good in the first 200 ms (ICC200: 0.843 (0.42- 0.96) 95% CI), p=0.004, CV= 10.4% (7.4- 16.4)), but was poor and non-significant from 200-600 ms. In the last two time-epochs reliability was fair and good, respectively (ICC800: 0.70 (-0.14- 0.92), p=0.037, CV=27.9% (20.6-44.1); ICC1000: 0.80, (0.24-0.95), p=0.01, CV=18.4% (14.4-29.5)). Conclusions: This new approach to quantifying landing stability showed good perspectives as an evaluation tool, both the initial landing stability measure, as well as for the stability epochs 600-1000 ms after landing. The early stability may be most useful to evaluate risk of lower limb injury, since injuries occur in this early time period after landing. However, the relatively large CV indicates that it may be most useful for group interventions and less useful for individual feedback. 47.