Myocardial adaptation and weight fluctuation of seven college wrestlers was examined during a competitive season. Standard M-mode measurements were used to determine left ventricular (LV) end diastolic and end systolic dimensions, fractional shortening, LV diastolic posterior wall thickness (DPW), diastolic interventricular septal thickness (DIVS), and LV mass (LVM) during preseason (test 1) and four months later at the season's end (test 2). The wrestlers' qualifying weights ranged from 53.6 to 80.5 kg and each competed in an average of 17 meets. Systolic and diastolic blood pressure, heart rate, and body weight (BW) were measured at both tests. Daily weight records and qualifying weights were used to calculate seasonal weight fluctuation as a percentage of the highest weight attained between each meet and the wrestler's subsequent qualifying weight. Paired t-tests were used to determine differences between tests 1 and 2. DPW, DIVS and LVM increased from 8.8 +/- 1.0 to 10.3 +/- 1.0 mm, 7.9 +/- 1.5 to 9.9 +/- 0.6 mm, and 171.2 +/- 24.3 to 209.7 +/- 12.9 mm3 respectively while BW declined from 70.3 +/- 9.2 to 67.1 +/- 9.4 (X +/- SD, p < .01) from test 1 to 2. The other variables remained constant across tests. The wrestlers' mean % weight fluctuation throughout the season was 7.5 +/- 1.5 ranging from 4.4 to 9.1%. These findings suggest that significant increases in myocardial mass occur over the course of a competitive wrestling season resulting from increased LV wall thickness. The magnitude and cyclic method of weight loss used by wrestlers does not appear to prevent myocardial hypertrophy.