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Cardiac responses to exercise in competitive child cyclists
T Rowland1, M Wehnert, K Miller
1Department of Pediatrics, Baystate Medical Center, Springfield, MA 01199, USA.
Medicine and Science in Sports and Exercise
|April 25, 2000
Summary
Highly trained child cyclists exhibit enhanced maximal stroke volume, a key factor in their superior maximal oxygen uptake (VO2max). Factors influencing resting stroke volume also contribute to performance differences in young athletes.
Area of Science:
- Pediatric Exercise Physiology
- Cardiovascular Adaptations to Training
Background:
- Cardiovascular responses to exercise in young endurance athletes are not fully understood.
- Childhood competitive cycling represents a unique model for studying exercise adaptations.
Purpose of the Study:
- To compare hemodynamic responses during progressive cycle exercise in child cyclists versus untrained boys.
- To elucidate the determinants of maximal oxygen uptake (VO2max) in young endurance athletes.
Main Methods:
- Doppler echocardiography and gas exchange analysis were employed.
- Cardiovascular variables were assessed during submaximal and maximal exercise.
Main Results:
- Cyclists achieved a significantly higher mean VO2max (60.0 mL x kg(-1) x min(-1)) compared to nonathletes (47.0 mL x kg(-1) x min(-1)).
- Cyclists demonstrated greater stroke index at rest and maximal exercise.
- Stroke volume plateaued at low exercise intensities in both groups.
Conclusions:
- Maximal stroke volume is a critical determinant of high VO2max in child cyclists.
- Factors influencing resting stroke volume are important for VO2max differences between trained and untrained children.