Comparison Of Cardiorepiratory Responses To Static And Combined Leg-press Exercise

Introduction
The difference in the cardiorespiratory responces to dynamic and static exercises, to unilateral and bilateral exercise,
and to exercises of upper limbs and lower limbs have been investigated[1.2]. Those studies have dealt with comparison
of upper and lower limb exercise, but few studies have reported the difference in cardiorespiratory response between
different types of exercise done in the different legs respectively at the same time. The purpose of this study is to
investigate the cardiorespiratory responces to a static and a dynamic exercise in combined settings.

Methods
Seven males subjects (172.5±6.6cm, 65.5±9.3kg, 20.0±0.7yrs) in a seated position perfomed isometric and combined
leg-press exercise which consisted of a static exercise by one leg and a dynamic exercise by the other leg. The
intensities of exercise were 20% (6min exercise) and 40% (3min exercise) maximal voluntary contraction (MVC).
Minute ventilation (VE), oxygen uptake (VO2), respiratory exchange ratio (RER), respiration rate (RR), heart rate
(HR), mean arterial blood pressure (MABP), rate-pressure product (RPP), and O2-pulse were measured before, during,
and after exercise in an environmental chamber (temperatur 20°C, humidity 50%).

Results
Figures show the cardiorespiratory responces to the combined, static, and dynamic exercise at 40%MVC.
Significant differences in VO2 during exercise were found between Comb40 and 1L40S, and between Comb40 and
1L40D. No significant difference in MABP during and after the exercises was found between Comb40 and 1L40S.

Discussion / Conclusions
The difference in the responces between the combined exercise and the unilaterl exercise may be attributed to the
difference in blood flow to the exercising limb since the cardiopulmonary responce to bilateral exertion was
demonstrated to be lower than the dual value of the unilateral exertion. The degree of this inhibitory response may
reflect the percent of MVC seemingly relating to the muscle perfusion pressure.
The high level of VO2, VE, and O2 pulse remaining for 45 seconds after the static and the combined leg-press in this
study indicate that the exercises were anearobic.

References
[1]. Asmussen E. (1981). Circ Res, Supp I 48(6), 3-10.
[2]. Ogita F. et al. (2000) Med Sci Sports Exerc, 32,1737-1742..

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