Jorjani Biomedicine Journal

Background and objective: Resistance training is a potential stimulus to increase muscle protein synthesis and the time under tension of muscle is one of the variables of strength training that contributes to its adaptation. The aim of this study was to investigate the effect of resistance training with slow and fast speeds on some anabolic and catabolic hormones in healthy young women. 
Material and Methods: This quasi- experimental study was conducted on 20 female students (mean age 21.65±2.03 years). The subjects were randomly and equally assigned to two groups with a time under tension of 1s-1s (fast contraction speed (FCS)) and 3s-3s (slow contraction speed (SCS)). The training load was the same in both groups and resistance training was done in a circular manner for six weeks, three days a week in eight stations. Blood samples were taken from the subjects to study the research variables before the training period and 48h after the last session of the training.
Results: There was no significant difference between the serum levels of GH(P = 0.82), IGF-1(P = 0.13) and cortisol(P = 0.59) in both groups, but the levels of myostatin in the fast group increased and in the slow group decreased, and the difference between the two groups was significant (P = 0.04). Also, in the strength test, the slow group experienced further increased strength. (P = 0.02)
Conclusion: : Although no significant changes in the levels of IGF-1, myostatin, and cortisol is observed in intragroup comparison at six weeks, resistance training with slow contraction speed can lead to further increases in the growth hormone levels and strength.

Background: Hypothyroidism is typically associated with a decreased basal metabolic rate, reduced energy expenditure, and weight gain. Exercise training and Dorema Aucheri (DA) have been identified as beneficial therapeutic strategies within complementary health approaches. Skeletal muscle metabolism and fiber type are regulated by innervation and soluble factors, such as thyroid hormones. However, the mechanisms between muscle function and hypothyroidism remain unclear.
Methods: Thirty mice were divided into five subgroups: the normal group; hypothyroid mice (HYPO, 8 mg/kg of propylthiouracil administered via intraperitoneal injection for 30 days); hypothyroid mice treated with DA (gavaged at 0.4 mg/kg for two months, five days per week); hypothyroid mice treated with exercise (75% VO2 max, 45 minutes per session, for two months, five days per week); and hypothyroid mice treated with both DA and exercise. The mRNA expression levels were detected via real-time qPCR.
Results: The data indicated that PPARγ, mTOR, and PI3K levels are reduced in hypothyroidism. DA and exercise enhanced PPARγ, mTOR, and PI3K levels in muscle tissue. Notably, DA and exercise significantly increased the expression levels of PPARγ, mTOR, and PI3K.
Conclusion: Exercise and DA, as alternative and complementary medicine, modified the PPARγ/mTOR/PI3K signaling pathways affected by hypothyroidism in mice.