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Cardiovascular responses to submaximal treadmill running in 11 to 13 year olds
Author(s) -
Armstrong N,
Welsman JR
Publication year - 2002
Publication title -
acta pædiatrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 115
eISSN - 1651-2227
pISSN - 0803-5253
DOI - 10.1111/j.1651-2227.2002.tb01682.x
Subject(s) - anthropometry , medicine , body surface area , heart rate , treadmill , stroke volume , cardiology , demography , physical therapy , blood pressure , sociology
The influence of age, sex, maturity, body size and body fatness on cardiac output (Q) and stroke volume (SV) during treadmill running at 2.22 m·s −1 was examined longitudinally. Mass, stature, triceps and subscapular skinfold thickness, and oxygen uptake (VO 2 ) were recorded and Q was estimated using the CO 2 rebreathing technique on each of three annual measurement occasions. Maturity was assessed using the indices for pubic hair described by Tanner. At the onset, subjects were 11.3 (0.4) y of age and data were available from a total of 274 Q determinations with equal numbers from boys and girls. Age‐, sex‐ and maturity‐associated changes in Q and SV adjusted for differences in body size and fatness were examined using multilevel regression modelling within an allometric framework. Changes in Q in both sexes were essentially in direct proportion to body surface area but, even with anthropometric variables controlled for, girls demonstrated a lower SV than boys, which was compensated for by a higher heart rate (HR) at each observation. Conclusion : At a given level of submaximal exercise over the age range 11–13 y Q is directly related to body size in both sexes. With body size and fatness controlled for, boys have greater SVs than girls when exercising at the same absolute VO 2 , Q and treadmill running speed. Age and maturation do not exert independent effects on either Q or SV.