Affiliations: [a] Institut Nacional d'Activitat Física de Catalunya Barcelona, Barcelona, Spain | [b] Fundació Universitària del Bages, Barcelona, Spain
Correspondence:
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Corresponding author: Júlia Jubany, Institut Nacional d'Activitat Física de Catalunya Barcelona, Av. de l'Estadi 12-22, Anella Olímpica, 08038 Barcelona, Spain. Tel.: +34 93 425 54 45; E-mail: jjubany@fub.edu
Abstract: Background:Measuring isometric strength is necessary in many areas of health and sport. However, trunk muscles have some particular characteristics that make them difficult to evaluate with simple, inexpensive instruments. Objective:To evaluate the reliability and validity of an instrument constructed with a hand-held dynamometer and a metallic structure (HHD+S) for measuring maximum isometric voluntary trunk muscle strength. Methods:Maximum isometric voluntary trunk muscle strength (extension, flexion and lateral flexion) was measured in 20 healthy individuals using the custom-made instrument (HHD+S) and the gold standard Back-Check (BC). Results:The results showed that the two instruments had high and similar intra-subject reliability. The validity of the HHD+S was demonstrated by the high Pearson coefficient correlation between the two instruments (r⩾0.78). Conclusions:Given the good trial reliability and the close correlation between the two instruments, we believe that the use of a hand-held dynamometer together with the custom-made metallic structure (HHD+S) allows an evaluation of the maximum isometric voluntary trunk muscle strength to be made, that is very similar in quality, accuracy and reliability to the BC.
Keywords: Maximum voluntary contraction, back strength, dynamometer, custom-made instrument
