이 연구의 목적은 12주간의 태권도 트레이닝이 남자 청소년의 골밀도와 골 건강관련 호르몬에 미치는 영향을 규명하는 것이었다. 연구대상자는 13~14세 남자 청소년 19명이었으며, 이들을 훈련군(12명)과 통제군(7명)으로 분류하였다. 골격성숙도는 TW3 방법을 적용하여 RUS 점수와 뼈나이를 평가하였고, 골밀도는 DXA를 이용하여 측정하였다. 골 건강관련 호르몬은 osteocalcin(OC), calcitonin(CC), parathyroid hormone(PTH), growth hormone(GH)과 25-hydroxyvitamin D(25(OH)D)를 분석하였다. 그룹 간 태권도 트레이닝 전·후 종속변인의 차이를 규명하기 위해 반복 이원분산분석을 적용하였고, 그룹 내 차이는 대응 t-검정을 이용하여 분석하였다. 골밀도와 뼈나이, 체중, 신장, 골 건강관련 호르몬의 관계를 규명하기 위해 다중회귀분석을 적용하였다. 이 연구 결과 훈련군의 전신 골밀도(p＜.001), 요추 골밀도(p＜.001), 전완 골밀도(p＜.01)는 12주 태권도 트레이닝 전·후 통계적으로 유의하게 증가하였으나 통제군은 유의한 변화가 없었다. 한편 대퇴 골밀도는 훈련군과 통제군 모두 12주 트레이닝 전·후 유의한 변화가 나타나지 않았다. OC는 훈련군(pre: 13.18ng/mL, post: 40.38ng/mL)과 통제군(pre: 13.04ng/mL, post: 40.89ng/mL) 모두 통계적으로 유의하게 증가한 반면, CC는 두 그룹 모두 유의한 변화가 없었다. PTH는 훈련군의 경우 통계적으로 유의하게 감소하였지만(p＜.05), 통제군은 유의한 차이를 보이지 않았다. GH는 트레이닝 전·후 훈련군과 통제군에서 유의한 상호작용효과가 나타났으며(p＜.05), 훈련군(pre: 0.70ng/mL, post: 4.22ng/mL)에서는 증가한 반면 통제군(pre: 5.40ng/mL, post: 2.04ng/mL)에서는 감소하였다. 25(OH)D는 훈련군과 통제군 모두 통계적으로 유의하게 감소하였다. 골밀도의 예측변인을 분석한 결과 훈련군에서 전신 골밀도의 경우 뼈나이, 제지방조직, 신장이 높은 설명력을 보였고, 요추 골밀도의 경우 뼈나이, 전완 골밀도의 뼈나이, PTH, 생활나이가 유의한 설명력을 나타냈다. 결론적으로 12주간의 태권도 트레이닝은 남자 청소년들의 골밀도와 골 건강관련 호르몬에 긍정적인 영향을 미친 것으로 나타났으며 태권도 트레이닝이 청소년들의 요추 골밀도에 영향을 미치기 위해서는 12주 이상의 장기간의 훈련을 통한 후속연구가 필요할 것으로 사료된다.

The purpose of the study was to evaluate the effects of weeks taekwondo training on bone mineral density, and calcemic hormones in male adolescents. 19 male adolescents aged 13-14 years (12 for training group; 7 for control group) were participated in this study. Taekwondo group has been performed 50 minutes a days a week for 12 weeks, as exercise intensity of 60-70 % HRR (heart rate reserver). Control group have only performed the activities included in their physical education classes. Skeletal maturity was assessed by TW3. Bone mineral density at the sites of lumber spine, forearm, femur and whole body were assessed by DXA (Hologic. QDR-4500, USA). Blood samples were drown in the morning after 12-h fast and spun at 3000 rpm for 15 min. 25(OH)D and calcitonin were analyzed by Liaison (Diasorin, USA). Osteocalcin was analyzed by COBAR 5010 (Quantum Packard. USA). Parathyroid hormone was analyzed by E170 (Roche, Germany) and growth hormone was analyzed by Immulite 2000 (DPC, USA). Statical analyses were done with SAS version 9.2. All data were presented in terms of means and standard deviations. Two-wany ANOVA with repeated measure was used for interaction of time x group. Paired t-test was perfomed to change over time in each parameter. Multiple regression analysis was used to find factors that influence dependent variables. A statistically significant level was defined as 95%. The results of this study indicates that bone age for TG (14.9±0.62yr) was significantly advanced compared to chronological age (14.0±0.64yr). but CG had similar bone age (14.1±0.55yr) compared to chronological age (13.9±0.46yr). significant within subjects effects were found for whole body BMD(p<.001), lumbar BMD (p<.001) and forearm BMD (p<.0001). Significant increase could be obtained in TG for whole body BMD, lumbar BMD, and forearm BMD between pre and post-tests However, there was no difference for femoral BMD for both TG and CG. Although no difference was found for serum osteocalcin in CG, significant increase could be observed in TG between pre and post-tests. There was significant within subject effect for PTH in TG (p<.05). Significant interaction effect of group and time was found for GH (p<.0001). serum 25 (OH)D was significantly decreased in both groups throughout the study periods. Bone age, serum calcitonin and lean tissue were predictors for whole body BDM in explaining 51.0%, 64% and 74.0% respective in TG. Bone age was significant predictor for lumbar BMD in explaining 39.0% in TG. In conclusion, 12 weeks taekwondo training has positive effects on bone mineral density and calcemic hormones in male adolescents. Further study is needed to enhance femral BMD as taekwondo training over 12 weeks and higher intensity.