Abstract
It is unclear whether cardiovascular responses to heavy isometric exercise are changed
by intensive training. We evaluated the effects of this type of exercise on left ventricular
(LV) function in athletes engaged in static and dynamic sport, compared with sedentary
persons, and looked for peculiarities in static athletes' responses that might reflect
adaptive mechanisms to their specific activity. The study population comprised 45
men (age 24 ± 5 years): 29 dynamic and 16 static athletes (runners and weightlifters,
respectively). The control group consisted of 20 age and gender-matched healthy sedentary
persons. All performed 50% of maximal voluntary contraction on a whole-body isometric
exercise device for 2 minutes. Echocardiographic calculations were determined at rest
and exercise. Upon exercise, stroke volume, cardiac output, end-diastolic volume,
and ejection fraction increased significantly in athletes, while end-systolic volume
and systemic vascular resistance decreased. In sedentary persons, stroke volume and
resistance remained unchanged, cardiac output and LV volumes increased, and ejection
fraction decreased from 67 ± 5% to 60 ± 5% (p <0.01 compared with rest; p <0.0001
compared with athletes). Whereas peak flow velocity decreased from 103 ± 10 to 81
± 6 cm/s in sedentary persons, it increased from 112 ± 9 to 126 ± 8 cm/s in the static
group and from 120 ±3 to 126 ± 9 cm/s in the dynamic athletes (p <0.0001 compared
with the sedentary group). Mean acceleration decreased in the sedentary group, remained
unchanged among the dynamic athletes, and increased among the static athletes. We
conclude that cardiovascular responses to heavy isometric exercise are modified by
intensive training. Athletes, taken as a group, react differently and adapt better
than sedentary individuals. Moreover, among them, those involved in static sport show
an improved cardiovascular adaptation to this type of exercise.
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Article Info
Publication History
Accepted:
August 26,
1996
Received:
June 10,
1996
Identification
Copyright
© 1997 Elsevier Science Inc. Published by Elsevier Inc. All rights reserved.
