The differentiation of the physiological left ventricular (LV) hypertrophy of the athlete's heart in opposition to a pathological finding may be problematic especially in both strength and endurance trained athletes with simultaneously large body dimensions: 64 male and 71 female rowers of regional up to national level were examined by (Doppler) echocardiography. In addition, the rowers were compared by matched-pair procedures both with 32 male and 30 female non-endurance trained (pairwise similar body surface area) and with 28 male endurance athletes (pairwise similar absolute heart volume). The so-called critical heart weight of 500 g was exceeded by 63% of the male and 11% of the female rowers. 9% of the male rowers showed even an LV muscle mass above the limit of 3.5 g.kg-1 body mass. The individual maximal body surface area-related values were 170 g.m-2 (men) and 133 g.m-2 (women). The LV enddiastolic internal diameter was measured to be above the upper clinical limit of 55 mm in 69% or 23% of the male and female rowers, although a maximal LV wall thickness of 14 or 13 mm, respectively, was never exceeded. The systolic LV function as well as ECG and blood pressure did not reveal any pathological findings, the diastolic LV function was measured within the (supra) normal range. The LV wall thicknesses, internal diameter and hypertrophic index (relation between wall thickness and internal diameter) were significantly higher in rowers than in non-endurance trained subjects, but similar if compared to the endurance athletes. The clinical limits, however, keep their validity until a body mass of about 70 kg. In conclusion, some upper absolute clinical limits, especially those referring to volume measurements, so far considered critical (LV internal diameter, heart weight and LV mass), may be clearly exceeded by healthy strength endurance trained athletes presenting high body dimensions. The LV wall thickness, however, rather exceptionally exceeded the clinical limits. If referring to body dimensions, the cardiac dimensions in rowers are still lower in comparison to highly-trained "pure" endurance athletes. A specific influence of the isometric exercise component on the LV hypertrophy cannot be observed.

Regarding the influence of the left ventricular (LV) adaptation by sports-specific factors the supposed endurance training have so far been compared mainly to strength conditioning. In the present study we investigated the echocardiographic LV measurements of endurance-trained athletes in different kinds of endurance sports (running and ball games) by using matched-pair procedures. We examined 22 male soccer players (S) and 22 male 400-m runners (R) on a regional up to a national level with--each similar in pairs--the following body mass (S: 75.7 +/-5.0 kg; R: 75.2 +/- 5.6), body surface area (S: 1.97 +/- 0.09 m2; R: 1.98 +/- 0.09), fat-free body mass (S: 68.4 +/- 4.6 kg; R: 68.3 +/- 5.3) and individual anaerobic threshold as a criterion to determine the running endurance (S: 14.23 +/- 0.79 km.h-1; R: 14.25 +/- 0.80). The body dimensions-related heart volume (HV/lean body mass: S: 14.2 +/- 1.5 ml.kg-1; R: 13.4 +/- 1.0) as well as the absolute and body surface-related LV internal diameter (EDD: S: 55.0 +/- 3.8 mm; R: 52.7 +/- 3.3; EDD/body-surface area: S: 27.8 +/- 1.9 mm.m-2; R: 26.6 +/- 1.3) were measured significantly higher in S as compared to R (p < 0.05 and p < 0.01, respectively). In both groups, free LV wall thickness, enddiastolic diameter and LV muscle mass correlated significantly with the body dimensions (fat-free body mass: r = 0.42 - 0.48 - 0.56; p < 0.004, respectively). In conclusion, specific sport-related strain like frequent exercises in interval form (typical for ball games) and a different volume/intensity ratio could significantly influence the LV adaptation beside the endurance performance as well as constitutional and genetic factors.

In combined strength- and endurance-trained athletes who are showing both unusual large body dimensions as well as a high physical fitness, the dimensions of the 'athlete's heart' are expected to reach physiological limits. Therefore we investigated 75 male and 77 female competitive rowers by means of doppler-echocardiography. The absolute "critical" heart weight of 500 g was exceeded by 61% of the male and 10% of the female rowers. Maximal values of the left ventricular (LV) muscle mass were measured at 170 (men) and 133 (women) g.m-2 body surface area, respectively. The LV end-diastolic internal diameter was measured to be above the upper clinical limit of 55 mm in 55% of the male and 17% of the female rowers. A LV wall thickness of 13 and 12 mm was only exceeded by 3 male and 1 female athlete, respectively (maximal values: 14 and 12.5 mm). The LV wall/internal diameter ratio did not exceed 48-50%. The systolic LV function as well as ECG and blood pressure did not reveal any pathological finding, the diastolic LV function was always measured within the normal range. The LV wall thicknesses, internal diameter and hypertrophic index (relation between wall thickness and internal diameter) of the rowers were significantly higher than those of 62 non-endurance trained athletes (pairwise matched according to the body dimensions) and similar to 28 male 'pure' endurance athletes (pairwise matched according to the absolute heart volume). In conclusion, upper limits of echocardiographic volume measurements that are considered critical may be clearly exceeded by healthy strength-endurance trained athletes with simultaneously high body dimensions. The clinical limits, however, are still valid in subjects with a body mass up to approximately 70 kg. The LV wall thickness only exceptionally exceed the clinical limits. A specific influence of the strength elements in training on the LV hypertrophy had not be found.