Effects of high intensity interval training with short and long-term intervals and detraining on glycolytic capacity in rat gastrocnemius muscle
Poster Presentation XML
Department of Exercise Physiology, Faculty of Exercise Physiology, University of Birjand
Introduction: High-intensity interval training (HIIT) forms an important component of athletes’ training. However, there are few data regarding the ability of HIIT forms to increase of glycolytic capacity and intramuscular metabolic adaptations. The goal of this study was to investigate the effects of two types of HIIT (8 weeks, 5 times/week) with short (HIIT1min: 16×1 min work at of 80-95% VO2max/1 min active recovery at 50-60% VO2max) and long (HIIT4min: 4×4 min work at of 80-95% VO2max/4 min recovery at 50-60% VO2max) interval time and 4 weeks detraining on the enzyme levels of phosphofructokinase (PFK) and glycogen synthase1 (GYS1), protein levels of monocarboxylate transporter 4 (MCT4) and lactate dehydrogenase (LDH) activity in rats gastrocnemius muscle.
Methodology: In this experimental study, 54 male Wistar rats (aged 3 months) were randomly assigned into three groups of 18 rats, including HIIT1min, HIIT4min and control (CT). Half of the rats (9 CTs and 9 from each trained group) were sacrificed after 48 hours of the last training session and the others after four weeks of detraining, and the gastrocnemius muscle was isolated to measure the levels of PFK, GYS1, MCT4 and LDH activity. Data analysis were performed using one-way ANOVA and Tukey's post hoc test (P<0.05).
Results: The results showed that, PFK levels in HIIT4min were significantly higher than HIIT1min (P=0.004) and CT (P=0.006), and after detrainig in HIIT4min Detraining (HIIT4minDT) significantly decreased compared to HIIT4min (P=0.002). The LDH activity in HIIT4min (P=0.0001) and HIIT1min (P=0.012) were significantly higher than the CT group and the trend of HIIT4min group to increase was more. There was no significant change in LDH activity after detraining compared to after training. No significant changes were observed in the level of GYS1 and MCT4 after HIIT.
Discussion: Eight weeks HIIT with long-term intervals induced more improvements in intramuscular glycolytic capacity than short-term. Some of these adaptations are maintained even after 4-week detraining.