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.

Abstract.[Purpose] The purpose of this research was to study the test-retest reliability of isometric knee extension muscle strength measurement using a hand-held dynamometer (HHD) with a belt, with healthy elderly people living in the community as subjects.[Subjects] The subjects were healthy elderly people living in the community, with an average age of 70.5 years, and measurements were made of the leg on the side that was used to kick a ball.[Method] The subjects sat on a mat table, and isometric knee extension muscle strength measurements using a HHD with a belt were conducted twice, at an interval of 30 seconds, with a knee flexion angle of 90 degrees. The measurement values were classified according to the gender of the subjects, and by age group 65-69 years, 70-74 years, and 75 years and above, and studied. Testretest reliability was studied using the intraclass correlation coefficient (ICC) and checks of the differentials.[Results] The ICC(1,1) between the first and second measurements ranged from 0.85 to 0.92. Apart from the group of men aged 75 years and above, the second measurement values were higher than those of the first.[Conclusion] Test-retest reliability of isometric knee extension muscle strength measurement using a HHD with a belt was high in healthy elderly persons. However, measuring only once, or measuring twice and taking the average was considered inappropriate, since there is the possibility that the values in such cases would be lower than the actual muscle strength.

[Purpose] The aim of this study was to develop a method of measuring isometric shoulder joint muscle strength using a handheld dynamometer with a belt and investigate its test-retest reliability. [Subjects] The subjects comprised 40 healthy adults. [Methods] Six types of isometric shoulder muscle strength were measured twice, and reliability was assessed. [Results] The intraclass correlation coefficient (1, 1) values ranged from 0.976 to 0.902. The result of a Bland-Altman analysis showed differences in the types of errors between measurement items. [Conclusion] The relative reliability of isometric shoulder muscle measurement using a handheld dynamometer with a belt was high. However, analysis of absolute reliability revealed errors that may affect interpretation of values; therefore, it was considered that adapting the greater of two measurement values is appropriate.

[Purpose] This study aimed to investigate the relatedness, reliability, and validity of isometric muscle strength measurements of hip abduction and abduction with an external hip rotation in a bent-hip position using a handheld dynamometer with a belt. [Subjects and Methods] Twenty healthy young adults, with a mean age of 21.5 ± 0.6 years were included. Isometric hip muscle strength in the subjects’ right legs was measured under two posture positions using two devices: a handheld dynamometer with a belt and an isokinetic dynamometer. Reliability was evaluated using an intra-class correlation coefficient (ICC); relatedness and validity were evaluated using Pearson’s product moment correlation coefficient. Differences in measurements of devices were assessed by two-way ANOVA. [Results] ICC (1, 1) was ≥0.9; significant positive correlations in measurements were found between the two devices under both conditions. No main effect was found between the measurement values. [Conclusion] Our findings revealed that there was relatedness, reliability, and validity of this method for isometric muscle strength measurements using a handheld dynamometer with a belt.