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Upper extremity and lower back moments during carrying tasks in farm children.
Gillette JC; Stevermer CA; Meardon SA; Derrick TR; Schwab CV
J Appl Biomech 2009 May; 25(2):149-155
Farm youth commonly perform animal care tasks such as feeding and watering. The purpose of this study was to determine the effects of age, bucket size, loading symmetry, and amount of load on upper body moments during carrying tasks. Fifty-four male and female participants in four age groups (8-10 years, 12-14 years, 15-17 years, and adults, 20-26 years) participated in the study. Conditions included combinations of large or small bucket sizes, unilateral or bilateral loading, and load levels of 10% or 20% of body weight (BW). During bucket carrying, elbow flexion, shoulder flexion, shoulder abduction, shoulder external rotation, L5/S1 extension, L5/S1 lateral bending, and L5/S1 axial rotation moments were estimated using video data. The 8-10 year-old group did not display higher proportional joint moments as compared with adults. Decreasing the load from 20% BW to 10% BW significantly decreased maximum normalized elbow flexion, shoulder flexion, shoulder abduction, shoulder external rotation, L5/S1 lateral bending, and L5/S1 axial rotation moments. Carrying the load bilaterally instead of unilaterally also significantly reduced these six maximum normalized joint moments. In addition, modifying the carrying task by using smaller one-gallon buckets produced significant reductions in maximum L5/S1 lateral bending moments.
Age-factors; Age-groups; Agricultural-workers; Agriculture; Animal-husbandry-workers Biomechanics; Children; Humans; Muscle-function; Musculoskeletal-system; Statistical-analysis; Author Keywords: Biomechanics; ergonomics; injury; inverse dynamics; posture
Department of Kinesiology, Iowa State University, Ames, IA
Issue of Publication
Journal of Applied Biomechanics
Iowa State University
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division