Effect of Six Weeks of High-Intensity Training on mTOR Phosphorylation and Quadriceps Femoris Muscle Features in Healthy Male Rats

Understanding the cellular signaling mechanisms involved in muscle hypertrophy is considered a scientific challenge. Mammalian target of rapamycin (mTOR) is one of the regulatory factors in this process that increases protein synthesis in skeletal muscle through phosphorylation. This study aimed to determine the effect of six weeks of high-intensity interval training (HIIT) on phosphorylated mTOR protein in the quadriceps muscles of adult male Wistar rats.

In this experimental study, 16 adult male Wistar rats (six weeks old and weighing an average of 190.93±4.97g) were used. The animals were randomly divided into two groups of control and training (n=8). The training group underwent six weeks of HIIT on a treadmill, with five sessions per week. The load was increased during the six weeks from repeating the interval of 30 meters per minute for 30 seconds in the first sessions to eleven repetitions of the interval of 35 meters per minute for 30 seconds at the end of the sixth week, with rest intervals between the intervals at a speed of 13 meters per minute for 60 seconds. The control group did not undergo any training. The mice were anesthetized, and the Vastus lateralis of the quadriceps muscle was extracted. The level of phosphorylated mTOR protein in the quadriceps muscle was measured using the immunohistochemical method.

HIIT significantly increased the levels of mTOR phosphorylation protein in male Wistar quadriceps femoris muscle compared to the control group (P<0.05).

Interval activity can have a positive effect on muscle hypertrophy through mTOR.