ABSTRACT
The purpose of this study was to determine the differences in the growth patterns of the external oblique (EO), internal oblique (IO), and transversus abdominis (TrA) muscles in adolescence baseball players. The subjects were 17 elementary school students (ES), 56 junior high school students (JS), and 21 high school students (HS) who played baseball. The EO, IO, and TrA muscle thicknesses were imaged using an ultrasound imaging device and analyzed separately on the dominant and non-dominant sides. Curve regression estimation of the relationship between EO, IO, and TrA and chronological age was used to read inflection points. An analysis of covariance was also performed, using body weight as a covariate for comparison with each of the EO, IO, and TrA grades. The inflection point readings showed that TrA was 11.26 years old (p<0.01, R2=0.45) for the dominant side and 10.10 years old (p<0.01, R2=0.46) for the non-dominant side, earlier than the inflection points of EO and IO. Analysis of covariance showed no significant difference in EO between any of the grades. IO showed significantly higher values for muscle thickness as the grade increased, both on the dominant and non-dominant side. TrA was higher for JS among ES and JS and higher for HS among ES and HS on both the dominant and non-dominant sides. EO may growth with increasing body size, while IO is interpreted to increase with increasing age due to the movement of baseball. TrA may grow earlier than EO and IO.
ABSTRACT
Objective@#To explore the influencing factors for the primary and secondary school students with abnormal angle of trunk rotation for the prevention.@*Methods@#The students of Grade Four to Nine in Jiashan County of Zhejiang Province were selected by cluster sampling method. A self-designed questionnaire was used to collect social demographic data, diet behaviors, physical activities, reading and writing habits. The angle of trunk rotation was measured by scoliometer. Logistic regression model was used to investigate the influencing factors for abnormal angle of trunk rotation. @*Results@#This study included 2 942 schoolchildren, with 1 582 ( 53.78% ) boys and 1 360 ( 46.23% ) girls. The incidence rate of abnormal angle of trunk rotation was 7.82%. The incidence rate of abnormal angle of trunk rotation in girls was 10.74%, which was higher than 5.31% in boys ( P<0.05 ). Grade ( OR=1.485, 95%CI: 1.058-2.085 ), gender ( OR=2.084, 95%CI: 1.536-2.828 ), frequency of eating fresh vegetables in the past week ( OR=0.749, 95%CI: 0.633-0.887 ) and watching electronic screen in the dark ( OR=1.188, 95%CI: 1.002-1.408 ) were the influencing factors for abnormal angle of trunk rotation in primary and secondary school students. Grade ( OR=2.664, 95%CI: 1.481-4.791 ) and watching electronic screen in the dark ( OR=1.325, 95%CI: 1.030-1.704 ) were influencing factors for abnormal angle of trunk rotation in boys. Frequency of eating fresh vegetables in the past week ( OR=0.714, 95%CI: 0.574-0.887 ) and uncorrected eyesight less than 5.0 ( OR=1.795, 95%CI: 1.164-2.767 ) were influencing factors for abnormal angle of trunk rotation in girls. @*Conclusion@#The abnormal angle of trunk rotation in primary and secondary school students is related to gender, grade, reading and writing behaviors as well as diets; and the influencing factors are different in male and female students.
ABSTRACT
The pitching motion requires neck, trunk and hip rotations. The purpose of this study was to investigate the relationship between pitching injuries and dominant versus non-dominant differences of the ranges of these motions. The subjects were 66 high school baseball pitchers who received medical checkup during baseball classes in Kyoto prefecture. During medical checkup, physical therapists measured the ranges of neck/trunk rotations, and internal rotation of the bilateral hips. Then orthopaedic doctors did special tests such as shoulder internal impingement test, subacromial impingement test, elbow valgus stress test and elbow hyper extension test. Fourteen pitchers (21.2%) who were positive in one or more special tests were judged to require second screening (injured group). In normal group, average neck/trunk rotations toward the non-dominant side were significantly wider than rotations toward the dominant side. Average hip internal rotation was significantly wider on the non-dominant side than on the dominant side. In injured group, a larger number of pitchers had wider neck and trunk rotation ranges toward the dominant side than toward the non-dominant side, and had wide hip internal rotation range on the dominant side compared to the non-dominant side. Comparing the ranges of the neck/trunk rotations and hip internal rotation between dominant and non-dominant sides might be useful for the prediction of pitching injuries of the shoulder and the elbow.
ABSTRACT
The purpose of this study is to evaluate physical characteristics of boxing players with/without low back pain (LBP). Materials and methods : 18 college boxing players were divided into two groups ; The first group consisted of eight subjects with LBP (LBP group), the other one consisted of ten subjects without LBP (no LBP group). The evaluation items were as follows : muscular strength of trunk extension/ flexion/ rotation, cross-sectional areas of the muscles of the lumber region, X ray photograph of lumber spine, MRI, general joint laxity test, muscle tightness test, muscle hardness, tenderness and moiré topography. Results : 9 out of 18 subjects showed lumber region abnormalities in their X ray photograph and MRI. The following evaluation items of LBP group read significant differences compared to those of no LBP group ; The trunk rotator peak torque was weaker at the angular velocity of 120 deg/sec, the laterality of SLR was significantly larger, while the finger floor distance value indicated significantly lower. Discussion : In LBP group, it is suggested that the decline of trunk flexion muscle strength possibly preceded the fall of trunk extension muscle strength which, however, was not observed.