Kinoshita, N., Oguma, Y., Katsukawa, F., Onishi, S., & Yamazaki, H. (2009). Do left ventricular dimensions further increase by continuing exercise training in already well-trained endurance athletes? A paper presented at the 14th Annual Congress of the European College of Sport Science, Oslo, Norway, June 24-27.

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This study evaluated long-term changes in left-ventricular dimensions in already well-trained female middle/long distance runners (N = 16) in a competitive high school team with national-level achievements. Ss had more than three years of experience as competitive runners before being recruited. In the high school team the intensity and distance of running increased (at a speed of 12-20 km/hour for 200-500 km/month). Echocardiography, underwater weighing, blood analyses, and maximal exercise tests were performed mostly at the beginning of the first semester and repeated after 206 months. Left-ventricular mass was calculated. Left-ventricular mass and left-ventricular end diastolic dimension were indexed to height, body surface area, and fat-free mass.

Many Ss had no or a few menstruations during the follow-up period. Height, free-fatty mass, and maximal oxygen uptake (VO2max) significantly increased but only by small amounts. The records for 1,500 and 3,000 m track races were significantly improved. There were no differences in weight, fat%, hemoglobin concentration, blood pressure, and resting heart rate. Although some left-ventricular mass indices increased significantly, structural features and features relative to other anthropological measures did not change.

Body scales, particularly free-fatty mass, were the most powerful predictor of left-ventricular dimensions. Ss trained hard enough to improve performance but without substantial increase in body scales. Ss' energy availability was low enough to become a/oligomenorrheaic (because they were supposed to be under the least hormonal influence). Ss' backgrounds yielded an optimal model to evaluate the independent effect of training on left-ventricular dimensions. They had already large left ventricles when compared to former published data and left-ventricular mass and left-ventricular end diastolic dimension increased further with training. However, the changes did not persist when indexed to free-fatty mass.

Implication. Left-ventricular dimensions hardly increase beyond what would be expected from increases in free-fatty mass that results from continued training in already well-trained female athletes. [This study suggests that once a fully trained state is achieved in mature female athletes, further physiological functions (in this case left-ventricular mass) should not be expected to change, that is, training does not "grow" extra capacity.]

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