title: Classifying performer strategies in drop landing activities.
abstract: Our purpose was to use group and single-case methods to examine inter-individual variability in the context of factors related to landing injuries. We tested the load accommodation strategies model (An exploration of load accommodation strategies during walking with extremity-carried weights. Human Movement Science, 35, 17-29) using landing impulse, revealing pre-landing strategies following height and external load manipulations. Ten healthy volunteers (8 male, 2 female, 24.0 ± 1.4 years, 1.72 ± 0.06 m, 73.5 ± 8.7 kg) were analysed across 12 trials in each of three load conditions (100% body weight [BW], 110% BW, 120% BW) from two landing heights (30 cm, 60 cm). Landing impulse (BW ∙ s) was computed for each participant-condition-trial, using impulse ratios (unit-less; BW ∙ s/BW ∙ s) to evaluate load accommodation strategies between adjacent load conditions (110%/100%, 120%/110%) at each landing height. Load accommodation strategy classifications were based on 95% confidence intervals (CIs) containing mechanically predicted impulse ratios (1.10 and 1.09 for 110/100% BW and 120/110% BW, respectively; α = 0.05). Mean group impulse ratios matched and exceeded predicted impulse ratios. Single-case analyses revealed a range of individual landing strategies that might be overlooked during group analyses, possibly uncovering individuals at greater risk of injury during landing activities.
authors.affiliation: a School of Kinesiology , University of Michigan , Ann Arbor , MI , USA.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Nordin
authors.affiliation: b Kinesiology and Nutrition Sciences , University of Nevada, Las Vegas , Las Vegas , NV , USA.
authors.forename: Janet S
authors.initials: JS
authors.lastname: Dufek
authors.affiliation: c School of Health Professions , Texas Tech University Health Sciences Center , Lubbock , TX , USA.
authors.forename: C Roger
authors.initials: CR
authors.lastname: James
authors.affiliation: d Department of Human Physiology , University of Oregon , Eugene , OR , USA.
authors.forename: Barry T
authors.initials: BT
authors.lastname: Bates
mesh_terms: D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000293:injuries / Q000502:physiology*; D008297:Male; D059385:Plyometric Exercise; D012307:Risk Factors; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult
keywords: Variability; height; impulse; load; single-case