Measurement of Isometric Shoulder Internal and External Rotation Strength with a Hand-Held Dynamometer Fixed by a Belt

Abstract

[Purpose] This study examined the inter-rater and intra-rater reliability of measurement of isometric shoulder internal and external rotation strength using a hand-held dynamometer (HDD).[Subjects] For intra-rater reliability, the subjects were 21 healthy persons (8 men and 13 women), and for inter-rater reliability, the subjects were 17 healthy persons (9 men and 8 women).[Method] For intra-rater reliability, an examiner performed measurements of isometric shoulder internal and external rotation strength twice with an interval of two days. For inter-rater reliability, two examiners measured isometric shoulder internal and external rotation strength. Making allowance for fatigue, measurements by different examiners took place after an interval of at least 30 min, and at random on the same day.[Results] The inter-rater and intra-rater reliability were analyzed using Student's t test, which showed no significant differences, and intra-class correlation coefficients, which gave good results.[Conclusion] Measurements of isometric shoulder internal and external rotation strength using a HDD fixed to the upper limbs and trunk by a belt gave good results for both inter-rater and intra-rater reproducibility.