2003 Volume 4 Issue 1 Pages 31-35
This study was designed to elucidate the physical features of tennis instructors and the relationship between those features and disorders that frequently occur among tennis instructors. For this purpose, we measured the range of motion of the shoulder and hip joints of tennis instructors as well as circumferences of their upper and lower extremities.
Subjects were 13 male tennis instructors (11 right-handers and 2 left-handers). Mean age was 34.2±8.4 years; height, 172.2±4.0 cm; body weight, 63.7±8.8kg; and BMI, 21.4±2.2. For statistical analysis, the paired, two-sided t-test was used. The range of motion of the shoulder joint on the dominant side was compared with that on the opposite side. The range of motion of the hip joint and circumferences of the upper and lower extremities were compared between the right and left sides. A P-value less than 0.05 was considered statistically significant.
Excursions of internal rotation and full rotation in the shoulder joint were restricted on the dominant side (P<0.05 and P<0.01, respectively). The excursion of external rotation of the hip joint was restricted on the left side (P<0.01). The circumference of the upper arm was larger on the dominant side than on the opposite side both in flexed and extended positions (P<0.001). The maximal circumference of the forearm was also larger on the dominant side (P<0.001).
The restriction of internal rotation of the arm on the dominant side seems to reflect a prodromal disorder that may progress to a clinically-significant disorder. The asymmetry of excursions of the hip joints is thought to be causally related to lumbago in some way. The larger arm circumference on the dominant side is obviously a result of the nature of tennis, in which the arm on the dominant side is consistently used. Periodic measurements of the range of motion of joints and the circumference of extremities may provide useful information in preventing the occurrence of disorders related to this sport.
