Relationship between energy costs and heart rate response to isometric quadriceps muscle exercise

ABSTRACT

The aim of this study was to study the relationship between oxygen consumption and heart rate to isometric and isotonic muscle contraction. Fourty healthy normal volunteers were participated in this study. Every subject was introduced to the testing procedures of static and dynamic muscle exercise for five minutes. Maximum voluntary contraction of the quadriceps muscle group was measured by using a dynamometer, and the oxygen consumption by Ergo-oxyscreen. The applied workload represented 30% mvc for every subject. The data collected of VOz max., VOz max/kg, HRmax., and breathing frequency during both dynamic and static exercises were statistically treated. It was found that there was no significant differences between VOz max/kg., and HRmax., during either static or dynamic type of muscle contraction. However, there was a positive linear correlation between VOz max., and heart rate during static and dynamic exercises. Thus, these findings indicate that the heart rate provides a valuable index of hemodynamic response to exercises, both dynamic and static, as well as determination of exercise intensity