Upper Extremity and Lower Back Moments During Carrying Tasks in Farm Children

• Autores: Jason C. Gillette, Catherine A. Stevermer, Stacey A. Meardon
• Localización: Journal of applied biomechanics, ISSN-e 1543-2688, ISSN 1065-8483, Vol. 25, Nº. 2, 2009, págs. 149-155
• Idioma: inglés
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• Resumen

  • 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.