[Purpose] The purpose of the present study was to establish the intra- and inter-rater reliability of measurement of extensor strength in the maximum shoulder abducted position and internal rotator strength in the 90° abducted and the 90° external rotated position using a hand-held dynamometer. [Subjects and Methods] Twelve healthy volunteers (12 male; mean ± SD: age 19.0 ± 1.1 years) participated in the study. The examiners were two students who had nonclinical experience with a hand-held dynamometer measurement. The examiners and participants were blinded to measurement results by the recorder. Participants in the prone position were instructed to hold the contraction against the ground reaction force, and peak isometric force was recorded using the hand-held dynamometer on the floor. Reliability was determined using intraclass correlation coefficients. [Results] The intra- and inter-rater reliability data were found to be “almost perfect”. [Conclusion] This study investigated intra- and inter-rater reliability and reveald high reliability. Thus, the measurement method used in the present study can evaluate muscle strength by a simple measurement technique.

[Purpose] The purpose of present study was to establish the same-session and between-day intra-rater reliability of measurements of extensor strength in the maximum abducted position (MABP) using hand-held dynamometer (HHD). [Subjects] Thirteen healthy volunteers (10 male, 3 female; mean ± SD: age 19.8 ± 0.8 y) participated in the study. [Methods] Participants in the prone position with maximum abduction of shoulder were instructed to hold the contraction against the ground reaction force, and peak isometric force was recorded using the HHD on the floor. Participants performed maximum isometric contractions lasting 3 s, with 3 trials in one session. Between-day measurements were performed in 2 sessions separated by a 1-week interval. Intra-rater reliability was determined using intraclass correlation coefficients (ICC). Systematic errors were assessed using Bland-Altman analysis for between-day data. [Results] ICC values for same-session data and between-day data were found to be “almost perfect”. Systematic errors not existed and only random error existed. [Conclusion] The measurement method used in this study can easily control for experimental conditions and allow precise measurement because the lack of stabilization and the impact of tester strength are removed. Thus, extensor strength in MABP measurement is beneficial for muscle strength assessment.

[Purpose] The purpose of the present study was to confirm the relationships between shoulder strength (extensor strength and internal rotator strength) of the abducted position and swimming power during arm-only swimming. [Subjects and Methods] Fourteen healthy male collegiate swimmers participated in the study. Main measures were shoulder strength (strength using torque that was calculated from the upper extremity length and the isometric force of the abducted position) and swimming power. [Results] Internal rotation torque of the dominant side in the abducted external rotated position (r=0.85) was significantly correlated with maximum swimming power. The rate of bilateral difference in extension torque in the maximum abducted position (r=−0.728) was significantly correlated with the swimming velocity-to-swimming power ratio. [Conclusion] The results of this study suggest that internal rotator strength measurement in the abducted external rotated position and extensor strength measurement in the maximum abducted position are valid assessment methods for swimmers.

Sharp et al. 13 Biokinetic swim bench 22.86mCostill et al. 1 2 Biokinetic swim bench 22.86mToussaint et al. 21 MAD-•原著論文 簡易型測定装置を用いた泳パワー計測の有用性 Usefulness of swimming power measurement using simplified apparatus 〔abstract〕The aim of this study is to investigate the usefulness of a new swimming power measurement apparatus. This apparatus is called the Drag Boat (DB). DB is as large as a floating kickboard. The body is made of wood, and the load can be selected from five different levels. Drag force and swimming power can be calculated by measuring swimming velocity.Calibration of this system was performed using a towing apparatus (Active Drag System, ADS). Towing velocity was in the range of 0.4~2.2m/sec. The subjects were ten male competitive swimmers. They swam 25m front crawl at maximum effort under two conditions. One was conducted in free swimming, and the other was semi-tethered swimming using DB and ADS.Significant linear relationship was observed between drag force and swimming velocity when the subjects swam towing DB.The swimming power calculated using DB was found to be significantly correlated with velocity of 25m sprint swimming (r = 0.73, p<0.05). There was also a significant correlation between swimming power and velocity of 25m sprint swimming, which were calculated using ADS (r = 0.82, p<0.01). The swimming power calculated using DB and the swimming power calculated using ADS were found to have a significant correlation (r = 0.83, p<0.01). The above results show that power measurement using DB is efficient.