Assessment of waveform similarity in youth long-distance runners.

Although unimpaired gait is typically assumed to be symmetrical, side-to-side differences in discrete instances of time have been reported in adult and youth runners. These previous results fail to account for the entirety of the motion.Are waveform pattern similarities strong in youth long-distance runners and are the waveform pattern similarities influenced by sex and maturation?A cohort of injury-free children and adolescents (n = 103) who participated in long-distance running activities were recruited for the study. Three-dimensional kinematics were collected as participants ran on a treadmill at a self-selected speed. Lower extremity side-to-side waveform symmetries were assessed using the Linear Fit Model. Unpaired t-tests and one-way ANOVA with post-hoc analysis were calculated to determine if sex and/or maturation influenced waveform symmetries.As a whole, waveform similarities were found to be strongest in the sagittal plane and weaker, but still of appropriate strength, in the coronal and transverse planes. Hip rotation and knee varus/valgus measures were found to have the weakest waveform similarities. High waveform similarity variability was measured within the cohort, particularly in the coronal and transverse planes. Waveform similarities were not found to be influenced by either sex or maturation.While the group as a whole demonstrated strong waveform similarities, some level of asymmetry in a population of uninjured, long-distance youth runners is normal as none of the measures demonstrated perfect symmetry. Prospective study is warranted to identify thresholds of waveform similarity and to determine if these findings can be used to predict running performance and injury risk.