Abstract
The object of the study was to investigate possible myocardial adaptations to intensive
body building training and to differentiate them from the athlete's heart resulting
from high intensive endurance training. Seven top-level body builders (BB) were examined
by one- and two-dimensional echocardiography and bicycle ergometer step test. They
were compared with seven highly endurance-trained athletes (E) using the matched pair
procedure. BB showed normal blood pressure at rest and during ergometric exercise;
their ergometric performance was in the normal range of sedentary subjects. Absolute
left ventricular muscle mass (LVMM) as well as one-dimensional measurements of wall
thickness and internal diameters were found to be similar in BB and E, while body
weight and surface-related values were clearly higher in E. The ratios between LV
myocardial thickness and internal diameter (M-mode) as well as between LVMM and LV
volume (combined one- and two-dimensional method) were not statistically different
between BB (0.356±0.077 and 1.10±0.16) and E (0.436±0.062 and 1.26±0.21). LV contractility
was similar in both groups. Diastolic parameters showed only a slight tendency toward
slower isovolumetric relaxation in BB. A significant correlation existed between lean
body mass and LVMM in BB but not in E.
The findings suggest that intense body building over a period of several years does
not induce any form of concentric hypertrophy. Analogously to the increase in body
dimensions, body building also causes an increase in heart size with an unchanged
mass/volume ratio. There is no evidence of an enlargement of the heart in relation
to body weight, as occurs in endurance athletes.
Key words
Echocardiography - endurance training - strength training - cardiac function
