Introduction High-intensity interval training is a time-efficient strategy for promotion of health by physical exercise (Gibala et al. 2012). We
investigated whether the changes in training intensity between the six training sessions over the period of two weeks of high-intensity
interval training (HIT, Wingate protocol) are related into the changes in aerobic fitness (VO2max) and anaerobic capacity (blood lactate). Methods 13 healthy sedentary middle-aged men (age 48 ± 5 years and BMI 25.8 ± 2.9) trained six HIT sessions within two weeks using
Monark 894 E ergometer. A session consisted of 4 -6 x 30 s maximal sprints (Wingate protocol) with 4 min rest between the sprints. The
amount of training was increased after every second session (4->5->6 sprints). The Monark anaerobic test software 3.0.1 with the ergometer
provided detailed information of the different parameters related to training intensity during the sprints and we selected peak
(PEAK) and average (AVG) power and power drop (DROP) to be the most representative parameters of the training load. As the amount of
sprints differed, we took only the first four sprints from every session for the analysis. The subjects did also VO2max test (cycle ergometry,
start intensity 50 W, increased 30 W every two minutes until to the volitional fatigue) before and after the training. One subject abandoned
the study due to personal reasons. Results VO2max improved by 6.2 % (from 34.0 ± 3.7 to 36.2 ± 4.5 ml/kg/min p=0.005) and blood
lactate 28.6% (from 10.8 ± 1.7 to 13.8 ± 2.7 mmol/l p<0.001) after the training. Average power in the sprints increased during the training
period and this was especially due to increase in power in the third and fourth sprint (about 10%). Power drop in the sprints decreased
during the training intervention (from about 58 at the first training session to 51 % at the last training session, p<0.05). Peak power remained
unchanged. We found no correlation between the changes in the training data with VO2max or blood lactate improvements.
Discussion Both aerobic fitness and anaerobic capacity were improved by HIT training, but these changes cannot be predicted by the
changes in the training performance. References Gibala MJ, Little JP, Macdonald MJ, Hawley JA. (2012). J Physiol, 590(Pt 5):1077-1084