Int J Sports Med 2013; 34(02): 158-164
DOI: 10.1055/s-0032-1311650
Orthopedics & Biomechanics
© Georg Thieme Verlag KG Stuttgart · New York

Hand-rim Forces and Gross Mechanical Efficiency at Various Frequencies of Wheelchair Propulsion

J. P. Lenton
1   Peter Harrison Center for Disabilly Sport, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom
3   Exercise and Sport Science, Manchester Metropolitan University Cheshire, Crewe, United Kingdom
,
L.H. V. van der Woude
2   Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, Netherlands
,
N. E. Fowler
3   Exercise and Sport Science, Manchester Metropolitan University Cheshire, Crewe, United Kingdom
,
G. Nicholson
4   ASPIRE Centre for Disability Sciences, Institute of Orthopaedics and Musculosketal Science, University College London, London, United Kingdom
,
K. Tolfrey
1   Peter Harrison Center for Disabilly Sport, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom
,
V. L. Goosey-Tolfrey
1   Peter Harrison Center for Disabilly Sport, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom
› Author Affiliations
Further Information

Publication History



accepted after revision 21 March 2012

Publication Date:
23 August 2012 (online)

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Abstract

To determine the effects of push frequency changes on force application, fraction of effective force (FEF) and gross efficiency (GE) during hand-rim propulsion. 8 male able-bodied participants performed five 4-min sub-maximal exercise bouts at 1.8 m·s − 1; the freely chosen frequency (FCF), followed by 4 counter-balanced trials at 60, 80, 120 and 140% FCF. Kinetic data was obtained using a SMARTWheel, measuring forces and moments. The GE was determined as the ratio of external work done and the total energy expended. Increased push frequency led to reductions in peak resultant force (P<0.05), ranging from 167 to 117 N and peak tangential force (P<0.05), ranging from 117 to 77 N. However, FEF only demonstrated a significant difference between 60% and 140% FCF (69±9% and 63±7, respectively; P<0.05). Work per cycle decreased significantly (P<0.05) and rate of force development increased significantly (P<0.05) with increased push frequency. GE values were significantly lower at 60%, 120% and 140% FCF than 80% and 100% FCF (P<0.05). No meaningful associations were present between FEF and GE. Under the current testing conditions, changes in push frequency are accompanied with changes in the absolute force values, albeit without changes in either the gross pattern/trend of force application or FEF. Changes in GE are not explained by different levels of force effectiveness.