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JOURNAL
OF
SPORTS SCIENCE &
MEDICINE
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Research
article
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RELATIONSHIP BETWEEN MAXIMUM SHOULDER EXTERNAL ROTATION ANGLE DURING THROWING AND PHYSICAL VARIABLES |
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Koji Miyashita  ,
Yukio Urabe, Hirokazu Kobayashi, Kiyoshi Yokoe, Sentaro Koshida, Morio Kawamura
and Kunio Ida |
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Dept. of Sport Rehabilitation, Division of PT & OT Sciences, Graduate School of Health Sciences, Hiroshima University, Kasumi1-2-3, Minami-ku, Hiroshima, Japan |
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© Journal of Sports Science and Medicine (2008) 7, 47 - 53 Search Google Scholar for Citing Articles |
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| ABSTRACT | |||
| The amount of stress imposed on shoulder and elbow appears to
be directly correlated with the degree of maximum shoulder external rotation
(MER) during throwing motions. Therefore, identifying risk factors contributing
to the increase of MER angle may help to decrease the throwing injuries
occurrence in baseball players. The purpose of the present study was to
demonstrate the correlation between MER and the kinematic variables at stride
foot contact (SFC) during the early cocking phase, the passive range of
motion (ROM), and the shoulder strength. The subjects were 40 high school
baseball players. Each subject carried out five throwing tasks with his
maximum effort. A three-dimensional analysis was performed to obtain the
MER, and the shoulder angles of external rotation (ER), extension and abduction
at SFC in the early cocking phase. The ROM and muscle strength of the shoulder
ER and internal rotation (IR) were also measured. Significant moderate linear
correlations were found between the MER and the ER (r = -0.32, p = 0.04)
at SFC, extension angle ( r= 0.35, p = 0.03) at SFC, IR strength (r = -0.30,
p = 0.04) and passive ROM of ER (r = 0.46, p = 0.01). The shoulder IR and
extension angles at SFC may determine the degree of the MER angle. Furthermore,
weak IR muscle strength and excessive ROM of ER might be risk factors for
shoulder and elbow injuries. The finding will enable us to establish better
prevention and rehabilitation strategies for throwing injuries in baseball
players.
Key words: Throwing, shoulder, elbow, injury prevention. |
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