Spinal loading during manual materials handling in a kneeling posture.
Stooped, restricted, kneeling, and other awkward postures adopted during manual materials handling have frequently been associated with LBP onset. However, lift assessment tools have focused on materials handling performed in an upright, or nearly upright standing posture. Unfortunately, many of the tools designed to analyze standing postures are not easily adapted to jobs requiring restricted postures. Therefore, the objective of this study was to evaluate spinal loading during manual materials handing in kneeling postures and determine if those loads can be predicted using simple regression. An EMG-driven biomechanical model, previously validated for upright lifting, was adapted for use in kneeling tasks. Subjects knelt under a 1.07m ceiling and lifted luggage of six weights (6.8, 10.9, 15.0, 19.1, 23.1 and, 27.2kgf) to one of four destination heights (0, 25.4, 53.3, 78.7cm). Spine loading was significantly affected by both destination height and load weight. Destination height increased compression, AP shear and lateral shear by an average of 14.5, 3.7 and 6.6N respectively per cm height increase. Load weight increased compression, AP shear and lateral shear by an average of 83.8, 27.0 and 13.1N respectively per kgf lifted. Regression equations were developed to predict peak spine loading using subject height, load weight and destination height with R(2) values of 0.62, 0.51 and 0.57 for compression, AP and lateral shear respectively.
Splittstoesser
Riley E
RE
The Ohio State University, Department of Industrial, Welding, and Systems Engineering, 1971 Neil Avenue, Room 210, Columbus, OH 43210, United States.
Yang
Gang
G
Knapik
Greg G
GG
Trippany
David R
DR
Hoyle
Jeff A
JA
Lahoti
Parul
P
Korkmaz
Sahika Vatan
SV
Sommerich
Carolyn M
CM
Lavender
Steven A
SA
Marras
William S
WS
D000328:Adult; D006801:Humans; D017770:Lifting; D008297:Male; D008954:Models, Biological; D009119:Muscle Contraction / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D013131:Spine / Q000502:physiology*; D013314:Stress, Mechanical; D013647:Task Performance and Analysis; D016474:Weight-Bearing / Q000502:physiology*