Journal of Sport and Exercise Physiology

Journal of Sport and Exercise Physiology

Comparing the effect of 8 weeks of continuous aerobic and high intensity interval training on soleus muscle gene expression of mTORC1, eEF2K, and eEF2 in male Wistar rats

Document Type : Original Article

Authors
Kia Salimi 1
Masoomeh Alvandi 2
Rahman Soori Soori 1
Ali asghar Ravasi 1
1 Department of Exercise Physiology, Faculty of Sport and Exercise Sciences, University of Tehran, Tehran, Iran
2 Department of Biological Science in Sport and Health, University of Shahid Beheshti, Tehran, Iran
10.48308/joeppa.2025.238426.1333
Abstract
Background and Purpose: The mechanism of muscle protein synthesis is regulated by the mTORC1 pathway and specific downstream signaling factors such as Eukaryotic Translation Elongation Factor 2 (eEF2), which maximize skeletal muscle fiber hypertrophy. The aim of the present study was to compare the effects of eight weeks of continuous aerobic training and high-intensity interval training (HIIT) on the gene expression of mTORC1, eEF2K, and eEF2 in the soleus muscle of male Wistar rats.
Material and Methods: For this purpose, twenty-four male Wistar rats (8 weeks old; weight, 280-300 g) were randomly divided into three groups: HIIT (n=8), continuous aerobic training (n=8) and control (n=8). The training protocol consisted of eight weeks of continuous aerobic and HIIT program (three times per week) at a 15° incline. The HIIT protocol included eight minutes of high intensity repetitions at an intensity of 85-95% V̇O2max followed by active recovery at an intensity of 50-60% V̇O2max. The intensity of the exercise increased from two full repetitions in the first week to five repetitions. In the continuous aerobic group, the rats ran at an intensity of 65-75% of V̇O2max and the training time increased from 30 minutes in the first week to 60 minutes in the fourth to last week. For warm-up and cool-down, the subjects ran at 40-50% of V̇O2max for 10 minutes at the beginning and end of each training session. Fourty eight hours after the last training session, the soleus muscle of the rats was extracted and the factors were evaluated by real-time PCR. Data were analyzed using one-way ANOVA with LSD post-hoc test at a significance level of α=0.05.
Results: The results of the study showed that continuous training significantly increased the ratio of soleus muscle weight to body weight (p=0.01) and the expression of eEF2K (p=0.002). Moreover, mTORC1 expression was significantly elevated in the continuous aerobic group (p=0.001). However, changes in eEF2 expression were not statistically significant (p>0.05). The HIIT also led to significant increases in mTORC1 (p=0.001), eEF2K (p=0.05), and the soleus muscle-to-body weight ratio (p=0.05), while no significant changes were observed in eEF2 expression (p>0.05).
Conclusion: Our results showed that 8 weeks of continuous aerobic training and HIIT on a treadmill at a 15° incline increased mTORC1 gene expression and the ratio of soleus muscle weight to body weight. Given the increased expression of eEF2K and no changes in eEF2 in both exercise groups, it appears that the elongation pathway does not play a major role in the potential hypertrophy caused by either training modality.
Keywords
Continuous aerobic training
high intensity interval training
eEF2
eEF2K
mTORC1
Subjects
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  • Receive Date 20 January 2025
  • Revise Date 26 April 2025
  • Accept Date 19 May 2025
  • First Publish Date 19 May 2025
  • Publish Date 23 September 2025