The Feasibility of a Measurement Method Using a Hand-held Dynamometer of Hip Extensor Strength in the Sitting Position

[Purpose] To examine the feasibility of a measurement method using a hand-held dynamometer (HHD) of hip extensor strength in the sitting position. [Subjects] The subjects were 20 healthy male adults. [Methods] Subjects performed an isometric hip extensor task in the sitting, standing and prone positions. Muscle strength was measured with a HHD, and the activities of the hip and trunk muscles were measured using surface electromyography (sEMG). The measurement reliability, the differences in muscle strength and muscle activity among the positions, and their correlation were investigated. [Results] The reliability was significantly high in the sitting position, and the muscle strength value was significantly higher in the standing, followed by the sitting position, than the other position. There was no significant difference in the muscle activity of the gluteus maximus (GM) between the standing and sitting positions, and both muscle strength and sEMG of GM showed high correlations between the sitting and prone positions. [Conclusion] Measurement reliability is high in the sitting position, and there is a correlation with the values measured in the prone position. However, it is necessary to note that the muscle strength values of the sitting and prone positions are different.