Abstract.[Purpose] The aim of this study was to evaluate the test-retest reliability of isometric muscle strength measurements made using a hand-held dynamometer restrained by a belt.[Subjects] The subjects were 37 healthy adults (18 men and 19 women) with a mean age of 21.9 years.[Methods] Measurements were made on the dominant leg using a hand-held dynamometer (µTas MF-01 or F-1, Anima Corp., Tokyo) and a belt to fix the position of the body part under test. The strengths of the following 10 muscle groups were evaluated: flexors, extensors, abductors, adductors, internal rotators and external rotators of the hip; flexors and extensors of the knee; and dorsiflexors and plantar flexors of the ankle. Each measurement was repeated after at least 30 seconds of rest in three sessions: in the morning, in the afternoon on the same day, and one week later.[Results] The intraclass correlation coefficient (ICC) for the first and second sets of measurements made in each session ranged from 0.75 to 0.97. ICC for the highest measurements of each muscle group in each of the three sessions ranged from 0.56 to 0.91.[Conclusions] The test-retest reliability of isometric muscle strength measurements of the lower limb made using a hand-held dynamometer equipped with a stabilizing belt varies widely, depending on the muscle action tested, and it would be better to repeat the measurements on different occasions.

Abstract.[Purpose] The aim of this study was to evaluate whether using a belt to restrain a hand-held dynamometer improves reliability of isometric leg muscle strength measurements in healthy subjects.[Subjects] Twenty to 44 healthy subjects participated in the test.[Methods] Two raters, one man and one woman, used a hand-held dynamometer with or without a restraining belt to measure the isometric strengths of the following muscle groups: flexors, extensors, abductors, adductors, internal rotators and external rotators of the hip; flexors and extensors of the knee; and dorsiflexors and plantar flexors of the ankle.[Results] The intraclass correlation coefficient, used to describe interrater agreement, ranged from 0.97 to 0.99 with the belt and from 0.21 to 0.88 without the belt. Pearson's correlation coefficient for measurements with versus without the belt ranged from 0.61 to 0.95 for the man and from 0.31 to 0.87 for the woman.[Conclusion] The interrater reliability of isometric leg muscle strength measurements was improved by use of a belt to restrain the hand-held dynamometer.

Abstract.[Purpose] The aim of this study was to evaluate the validity of isometric muscle strength measurements of the lower limbs and hips made with a hand-held dynamometer and belt by comparing them with measurements obtained by an isokinetic dynamometer.[Subjects] The subjects were 24 healthy adults (12 men, 12 women) with a mean age of 20.4 years.[Method] Measurements were made with both instruments on the flexors, extensors, abductors, adductors, external rotators and internal rotators of the hip and flexors and extensors of the knee.[Results] Measurements obtained with the hand-held dynamometer and belt were significantly lower than those obtained with the isokinetic dynamometer. Pearson's correlation coefficients for the measurements made with the two instruments ranged from 0.52 to 0.88 for all muscle groups except the hip abductors which was 0.34. In the hip abductors, the coefficient was 0.65 when forces of 450 N and higher were excluded.[Conclusion] Isometric muscle strength measurements of the lower limbs and hips obtained with a hand-held dynamometer and belt are considered to be valid except for measurement of hip abduction of subjects with high muscle strength.

[Purpose] The purpose of this study was to examine the reliability of three isometric knee extension strength measurements (IKE) made with a hand-held dynamometer (HHD) and a belt of healthy elderly living in the community as subjects. [Subjects] The subject cohort consisted of 186 healthy elderly people, aged 65 to 79 years, living in local communities. [Methods] IKE of the leg subjects used to kick a ball was measured. IKE of each subject was measured three times using an HHD-belt at intervals of 30 seconds. The reliability of the larger of the first two measurements (LV2) as well as the third measurement (3V) was investigated. [Results] The intraclass correlation coefficients [ICC (1, 1)] for LV2 and 3V were 0.955. Bland-Altman analysis showed a fixed bias, and the limits of agreement ranged from −5.6 to 4.6. [Conclusion] The ICC results show that the test-retest reproducibility of IKE measurements of healthy elderly subjects using an HHD-belt is high. However, Bland-Altman analysis showed a fixed bias, suggesting the need for three measurements.

This study aimed to determine the validity and reliability of isometric knee extension muscle strength measurements using a belt-stabilized hand-held dynamometer compared to that using an isokinetic dynamometer with the participant in a sitting posture. [Participants and Methods] Forty-two university students participated. The isometric knee extension muscle strength was measured using a hand-held dynamometer and an isokinetic dynamometer. For both measurements, the participants were in the similar sitting posture. The sitting posture maintained trunk stability, with the hands on the bed, and the non-measurement-side toe touching the floor or table. The intra-class correlation coefficient and the relevance were verified. [Results] Intra-rater correlation coefficient (1, 1) of the two measurements was ≥0.75. A significant difference was found in the measurement value between males and females. No significant difference was found between the measurements value of the two devices. A significant positive correlation was found in the measurement value of two devices in the male participants.[Conclusion] When compared to the standard method of isometric knee extension muscle strength measurements using an isokinetic dynamometer with the participant in the sitting posture, measurements using the belt-stabilized hand-held dynamometer were considered valid and highly reliable in the male participants.