Effects of standardized foot positions during the execution of a submaximal pulling task.
This study examined how experimentally controlled foot positions could affect the temporal and spatial parameters of a load (20% of subject mass) during a one-handed repetitive submaximal pulling activity. Foot positions standardized relative to a frontal and sagittal plane defining a pull force vector were derived based on the preferences of 45 volunteer subjects. In general, the subjects assumed asymmetrical foot positions and on average the big toe of the foot contralateral to the hand exerting the pull was located 19% (SD = 4.4) of stature in front of the frontal plane containing the pull origin and 8.6% (SD = 4.5) of stature laterally from the sagittal plane through which the load was displaced. The big toe of the foot ipsilateral to the hand exerting the force was located at a distance of 46.7% (SD = 6.3) of stature in front of the frontal plane containing the pull origin and 0.4% (SD = 3.9) of stature laterally from the sagittal plane through which the load was displaced. The left and right feet were orientated at angles of 56.8 degrees (SD = 20.2 degrees ) and 25.9 degrees (SD = 22.7 degrees ), respectively, relative to a right horizontal of a frontal plane parallel to the plane containing the origin of pull. These foot positions were subsequently employed in a second experiment to investigate how dictating foot positions would affect the way in which 15 newly recruited subjects exerted a pull force on the same load. Results from this experiment showed that the load velocities and forces were not affected by standardized foot positions when compared to those collected when subjects were free to choose foot orientations. It is suggested that future researchers should consider the benefits of employing standardized foot positions in studies of pull exertions, particularly for methodologies similar to that described in this study.
MacKinnon
Scott Netson
SN
Department of Human Kinetics and Ergonomics, Rhodes University, PO Box 94, Grahamstown 6140, South Africa. smackinn@mun.ca
D001696:Biomechanical Phenomena; D006804:Ergonomics; D005260:Female; D005528:Foot / Q000502:physiology*; D006801:Humans; D008297:Male; D013647:Task Performance and Analysis