Influence of footwear on Landing Error Scoring System outcomes

This is a randomized cross-over study performed in a biomechanics laboratory. Participants will complete the original Landing Error Scoring System testing procedures, jumping horizontally from a 30-cm box to 50% of their body height and jumping vertically as high as possible upon landing. Participants will jump three times in two conditions: (1) barefoot, and (2) their own habitual athletic footwear. There will be 15 minutes rest between conditions, and 30 seconds rest between trials. Participants will be allowed up to three familiarization trials before formal experimentation. Before each trial, participants will be reminded to jump to 50% of their body height (indicated by the line) with two feet, and jump upwards as high as possible upon landing. Trials will be disregarded when participants do not land at 50% of their body height or do not perform the task in one fluid motion. Unless the task is preformed inappropriately, feedback on performance will not given to avoid influencing outcomes. Two video cameras will be use to capture the jumps at 120 frames per second. One camera will be placed to the right hand side of participants, and the other in front of participants. Cameras will be placed 3.5 m away from the landing area on 1.3 m high tripods. The videos will be analysed in a video processing software (Kinovea) and the original Landing Error Scoring System template from Padua et al. (2009) used to extract Landing Error Scoring System scores. Briefly, the tool involves 17 items that is scored by an examiner. Movement during the double-leg jump-landing task is scored to identify "landing errors". The overall score ranges from 0 to 17 errors where lower scores reflect fewer landing errors and thus fewer movement patterns linked with noncontact Anterior Cruciate Ligament injuries The order of conditions will be block randomized prior to study commencement by a third party to ensure an equal number of participants starting in each condition, and allocated sequentially to participants upon study enrolment by a single researcher. Participants will be pre informed of the aims of the study. Participants will use their own athletic footwear, and will not be tested if their footwear score 70% or more on the Minimalist Index as could potentially mimic barefoot. Participants will complete an informed consent document, and baseline characteristics will be collected (height, mass, gender, age, and self-administered short-form International Physical Activity Questionnaire). Footwear characteristics will also be recorded using the Minimal Index and a durometer.