Relationship between isometric shoulder strength and arms-only swimming power among male collegiate swimmers: study of valid clinical assessment methods

Abstract

[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.

Clinical method to assess shoulder strength related to front crawl swimming power in male collegiate swimmers

“…The maximum isometric force was measured using a hand-held dynamometer (HHD) (Mobie MM100C; Minato Medical Science Co., Ltd., Japan), and extremity length, using a digital calliper (D-500; Niigata seiki Co., Ltd., Japan). Maximum isometric force and extremity length were used to calculate torque 4 ) . Extension force in the position of maximum shoulder abduction and internal rotation force in the position of abducted and external rotation were also measured.…”

“…Upper extremity length was defined as the distance from the acromion to the distal head of the third metacarpal bone on the dorsal side 4 ) . The forearm length was defined as the distance from the lateral joint line of the elbow to the distal head of the third metacarpal bone on the dorsal side 4 ) . The extension torque (ET) was calculated from the upper extremity length and the extension force.…”

“…The internal rotation torque (IT) was calculated from the forearm length and the internal rotation force. The rate of bilateral difference, defined as the bilateral difference between the dominant and non-dominant sides, was calculated using the equation [absolute (difference of both sides) / mean of both sides ×100] 4 ) . The rate of bilateral differences in ET (RBET) and the rate of bilateral differences in IT (RBIT) were calculated.…”

“…Swimming performances were captured using a moving image recorded by a digital video camera (HDR-CX270V; Sony Marketing Inc., Japan) (at 60 fps) poolside. Swimming velocity and the towing force of the 15-m swim were measured using the drag boat at three load levels 4 ) .…”

“…We investigated the relationship between arm-only swimming and shoulder strength and found that maximum swimming power (MSP) was significantly associated with internal rotator strength in the position of abducted and external rotation (r=0.85; p<0.001) 4 ) . Additionally, we reported that the swimming velocity-to-swimming power ratio (SVPR) was significantly correlated to the rate of bilateral difference in the shoulder extensor strength in the position of maximum shoulder abduction (r= −0.728; p=0.006) 4 ) . Although the link between shoulder strength and MSP in arm-only swimming has been investigated, the correlation between shoulder strength and MSP during front crawl swimming is still unclear.…”