Author(s): ITAYA, S., SAKAMOTO, R., WAKITA, M., FUJITA, K., YANASE, K., Institution: DOSHISHA UNIVERCITY, Country: JAPAN, Abstract-ID: 2068

INTRODUCTION:
The arm-swing motion has a significant impact on the jumping height. Previous study reported Performing the arm-swing motion obtain floor reaction force and generate jumping power (1). Shoulder joint functions, such as muscle strength and flexibility, influence the arm-swing movement, however, this has not been examined yet. The purpose of this study was to clarify the relationship between shoulder joint function and jumping height. The hypothesis was that greater muscle strength and flexibility of the shoulder joints correlates with jumping height utilizing arm-swing motion.
METHODS:
Participants were 30 healthy young men (20.9 ± 1.3 years, 173.4 ± 5.1 cm, 64.2 ± 9.9 kg). Using the Multi Jump Tester II (Qsfix, Inc., Japan), counter movement jump (CMJ) heights were measured under two conditions: with arm-swing and without arm-swing .Voluntary isometric maximal contractions (MVC) of the shoulder joint were measured in four directions; flexion, extension, abduction, and horizontal adduction using a hand-held dynamometer (Moby, Sakai Medical Co., Ltd., Japan). Shoulder joint range of motion (ROM) were taken in four directions; flexion, extension, abduction, and horizontal abduction using a goniometer. Muscle shear moduli were measured using the ultrasound shear wave elastography (Aixplorer, SuperSonic Imagine, France). The measurements were taken at the pectoralis major, pectoralis minor, trapezius, and latissimus dorsi muscle. Pearson correlation coefficient or Spearmans rank correlation coefficient were used to determine the association between the CMJ heights and these shoulder joint functions (MVCs, ROMs, and muscle shear moduli).
RESULTS:
The CMJ heights with arm-swing were correlated with all MVCs (flexion; r = 0.625, p < 0.01, extension; r = 0. 466, p < 0.01, abduction; r = 0.479, p < 0.01, horizontal adduction; r = 0.444, p < 0.05). On the other hand, the CMJ height without arm-swing was correlated with flexion MVC only ( r = 0.445, p < 0.05). No significant correlations were found between the CMJ height with/without arm-swing and the other measurements.
CONCLUSION:
Our results suggest that shoulder MVCs are correlated with CMJ height utilizing arm-swing.
However, jumping ability is influenced not only by the upper limbs, but also by the lower limbs and trunk. Therefore, it is necessary to examine the jumping ability involving both the lower limbs and the trunk.

References:
1)Mackay H,Br J Sports Med.2003

Contact:
cgtg0044@mail4.doshisha.ac.jp