The Effect of Anticipation on Limb Symmetry During the Landing Error Scoring System Test

The Landing Error Scoring System (LESS) is a field test consisting of a 17-item checklist that identifies the presence of biomechanical risk factors during a drop jump task that have been prospectively linked to non-contact lower extremity injuries. The standard LESS does not address limb differences or any element of anticipation that is often seen in the athletic settings. PURPOSE: The purpose of this study was to assess the influence of anticipation on limb symmetry during the landing error scoring system test. METHODS: All jumping trials were performed off a 30 cm platform into a marked area on the ground. A camera was used to record the participant’s jumps in the frontal plane and another camera was used to record the participant’s jumps in the sagittal plane. Participants first performed five anticipated drop jumps where they were explicitly instructed to perform a drop jump task. Then participants performed a series of unanticipated trials consisting of drop jumps and cutting maneuvers in a randomized order where they had to respond to a light stimulus instead of explicitly stated instructions. Participants performed the unanticipated trials until five successful drop jumps were collected. Drop jumps from both the anticipated and unanticipated trials were used for LESS analysis. Two separate paired t-tests were used to compare LESS scores between limbs. One t-test compared limbs for the anticipated drop jumps and one t-test compared limbs for unanticipated jumps. Additionally, a Pearson correlation was used for both jumps to assess for any relationship between limbs. RESULTS: There were no significant differences in LESS scores between limbs for both the anticipated and unanticipated jumps (p > .05). However, a significant strong positive correlation was shown between limbs for both the anticipated jumps (r = 0.89, p < .001) and the unanticipated jumps (r = 0.94, p < .001). CONCLUSION: The results indicate that in healthy individuals, practitioners can effectively implement the LESS for either (or both) limbs to determine risk of injury, as high LESS scores in one limb are associated with high LESS scores in the other limb.