청소년 무릎 등속성 운동 각속도 차이가 호흡순환계 변인에 미치는 영향

Abstract

The purpose of this study was to investigate the acute effects of isokinetic knee muscle contraction at different angular velocities on cardiorespiratory variables in middle school students. Thirty-eight boys without any medical problems were divided into normal(n=18) & obese(n=20) group over BMI 25kg·m2 or 25 percentage of body fat. Participants performed until all-out in pre-exercise test used Astrand cycle ergometer graded exercise protocol for measuring heart rate, oxygen uptake, metabolic equivalents, and ventilation. The cardiorespiratory variables were measured during isokinetic knee muscle contraction protocol with 5 repetitions at 30°·s-1 & 60°·s-1 and 25 repetitions at 180°·s-1 & 240°·s-1 with con/con cycle used isokinetic dynamometer(Humac Norm testing & Rehabilitation System, Cybex, USA) equipped with Electrocardiogram(CH 2000, Cambridge Heart, Incorporated) and Gas Analysis(Quark b2, COSMED Co., Italy). As a result, both normal and obese group, it was significantly different between 180°·s-1 & 240°·s-1 and 30°·s-1 & 6 0°·s-1 in total work done. In obese group, VO2 orderly increased slow speed(30°·s-1, 60°·s-1) and fast speed(180°·s-1, 240°·s-1) both normal and obese group, but ranged from 33.64% at 30°·s-1 and 45.64% at 180°·s-1 of obese group had significantly lower than on the basis 100% of normal group. HR’s trend also increased the about same pattern as VO2 ranged from 42.15% at rest to 80.61% at 240°·s-1. In obese group, MET orderly increased to angular velocities the same as VO2 and HR, lower level than normal group. The VE of normal group 85.58(L·min-1) at 100% showed, but the maximum value of obese group showed 65.01(L·min-1) at 76.14%.