Research Article: Performance and cardiac evaluation before and after a 3-week training camp for 400-meter sprinters – An observational, non-randomized study

Date Published: May 31, 2019

Publisher: Public Library of Science

Author(s): Michael Skalenius, C. Mikael Mattsson, Pia Dahlberg, Lennart Bergfeldt, Annica Ravn-Fischer, Nir Eynon.

http://doi.org/10.1371/journal.pone.0217856

Abstract

To study the performance and cardiovascular function after a 3-week training camp in athletes competing in an anaerobically dominant sport.

Twenty-three competitive 400-m athletes were enrolled in this non-randomized study, 17 took part in a 3-week training camp in South-Africa (intervention), but one declined follow-up assessment, while 6 pursued in-door winter training in Sweden and served as controls. Electrocardiography, transthoracic echocardiography, blood test analyses, maximal exercise tolerance test, and a 300-m sprint test with lactate measurements ([La]peak) were performed before and after the training camp period.

At baseline, there were no clinically significant pathological findings in any measurements. The training period resulted in improved 300m-sprint performance [n = 16; running time 36.71 (1.39) vs. 35.98 (1.13) s; p<0.01] and higher peak lactate values. Despite 48% more training sessions than performed on home ground (n = 6), myocardial biomarkers decreased significantly (NT-pro BNP -38%; p<0.05, troponin T -16%; p<0.05). Furthermore, resting heart rate (-7%; p<0.01) and left ventricular systolic and diastolic volumes decreased -6% (p<0.01) and -10% (p<0.05), respectively. Intense physical activity at training camp improved the performance level, likely due to improved anaerobic capacity indicated by higher [La]peak. There were no clinically significant adverse cardiac changes after this period of predominantly anaerobic training.

Partial Text

Participation in sports and exercise is an important lifestyle element for many people in the industrialized part of the world and generally considered beneficial for overall health [1]. Furthermore, there is a strong public interest in competitive sports even at the highest level [2]. For many athletes, participation at competitive level involves strenuous exercise and training, often inducing high cardiovascular load. It is therefore not surprising that specific electrocardiographic (ECG) features have been found in athletes compared with non-athletes as well as altered cardiac dimensions on transthoracic echocardiography (TTE) [3]. Of concern is, however, a small but not negligible risk of sudden cardiac death (SCD) among competitive athletes and pre-participation evaluation and its components are topics of debate [4, 5].

Baseline data for all 23 participants are presented in Tables 1 and 2. Twenty-two athletes participated on both occasions; there was one drop-out among the 17 participating in the training camp. Data before and after the training camp for 16 participants are therefore shown in Table 3.

We performed a thorough cardiovascular evaluation before and within 14 days after a 3-weeks training camp in South-Africa in 16 male competitive 400-m runners and a 300-m sprint test with lactate analyses before and after the training period. A “control group” of 6 runners of equal performance level underwent the same protocol, except the training camp. The performance of the sprint test improved after the camp and presumably due to improved lactate tolerance. There were no detectable cardiovascular adverse effects of the intensified training period.

The performance of a 300-m sprint test improved after three weeks of training in a warm environment and was presumably due to improved lactate tolerance. There were no detectable cardiovascular adverse effects of the intensified training period. On the contrary, we observed reduced LV volumes despite lower resting HR and decreases in plasma levels of myocardial biomarkers (NT-pro-BNP and troponin T) after this predominantly anaerobic type of training. Our observations extend the present knowledge of cardiovascular physiology in this subgroup of competitive athletes focusing on long-sprint performance.

 

Source:

http://doi.org/10.1371/journal.pone.0217856

 

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