A dynamical systems analysis of assisted and unassisted anterior and posterior hand-held load carriage.
Load carriage is recognised as a primary occupational factor leading to slip and fall injuries, and therefore assessing balance maintenance during such tasks is critical in assessing injury risk. Ten males completed 55 strides under five carriage conditions: (1) unassisted anterior, (2) unassisted posterior, (3) assisted anterior, (4) assisted posterior and (5) unloaded gait (UG). Kinematic data were recorded from markers affixed to landmarks on the right side of each participant, in order to calculate segment angles for the foot, shank, thigh and pelvis. Continuous relative phase (CRP) variability was calculated for each segment pair and local dynamic stability was calculated for each segment in all three movement planes. In general, irrespective of the assistive device or movement plane, anterior load carriage was most stable (lower CRP variability and maximum finite-time Lyapunov exponents). Moreover, load carriage was less dynamically stable than UG, displaying the importance of objectively investigating safe load carriage practices.
Dynamical systems analyses were used to comprehensively evaluate the stability of various handheld load carriage methods. In general, anterior load carriage was significantly more stable than posterior load carriage,Mover's assistive device had small but beneficial effects on stability, and load carriage was less stable than UG.
a School of Physical and Health Education, Nipissing University , 100 College Drive, Box 5002, North Bay, Ontario , Canada P1B 8L7.
Ryan B
RB
Graham
Catherine L W
CL
Smallman
Ross H
RH
Miller
Joan M
JM
Stevenson
D000328:Adult; D001696:Biomechanical Phenomena; D005528:Foot / Q000502:physiology; D005684:Gait; D006225:Hand; D064368:Healthy Volunteers; D006801:Humans; D007866:Leg / Q000502:physiology; D017770:Lifting; D008297:Male; D009068:Movement; D010388:Pelvis / Q000502:physiology; D004856:Postural Balance / Q000502:physiology; D012656:Self-Help Devices; D013647:Task Performance and Analysis; D013848:Thigh / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology*; D055815:Young Adult
Lyapunov exponents; assistive device; continuous relative phase variability; dynamical systems analysis; load carriage