title: Reliability of Mechanical Trunk Responses During Known and Unknown Trunk Perturbations.
abstract: This study evaluates the between-day reliability of a newly developed trunk perturbation test and compares mechanical response during known and unknown conditions. Mechanical trunk responses were measured in 17 female subjects during unloading and loading perturbations of the abdomen (A: preloaded abdomen condition) and low back (B: preloaded back condition). The loading perturbation increased the preload from 5.5 kg to a 10.9 kg pull on the trunk whereas the unloading perturbation decreased the pull from 5.5 kg to 0.1 kg. A sequence of loading (known), unloading (known), and randomized loading/unloading (unknown) perturbations were performed for A and B. Between-day reliability of stopping time, trunk displacement, and velocity was quantified using intraclass correlation coefficients (ICCs). ICCs were good to excellent for all loading and unloading measures during the known (0.70-0.98) and unknown (0.64-0.94) perturbations of A and B. In general, larger trunk displacements were seen after the unknown perturbations compared with the known perturbation. The method may be used as a diagnostic tool for screening workers who are in risk of future work-related low back injuries.
authors.affiliation: National Research Centre for the Working Environment, Copenhagen, Denmark.
authors.forename: Markus D
authors.initials: MD
authors.lastname: Jakobsen
authors.forename: Mikkel
authors.initials: M
authors.lastname: Brandt
authors.forename: Emil
authors.initials: E
authors.lastname: Sundstrup
authors.forename: Kenneth
authors.initials: K
authors.lastname: Jay
authors.forename: Per
authors.initials: P
authors.lastname: Aagaard
authors.forename: Lars L
authors.initials: LL
authors.lastname: Andersen
mesh_terms: D000009:Abdominal Muscles / Q000502:physiology; D000328:Adult; D064131:Back Muscles / Q000502:physiology; D001696:Biomechanical Phenomena / Q000502:physiology; D004867:Equipment Design; D005080:Exercise Test / Q000295:instrumentation; D005260:Female; D006801:Humans; D009068:Movement / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D011187:Posture / Q000502:physiology; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D060726:Torso / Q000502:physiology*