The Comparison of the Influence of 12-Week High- Intensity Interval Training and Continuous Moderate Intensity Training on PGC-1α and Tfam Mitochondrial Proteins Expressions in Gastrocnemius Muscle of Elderly Rats

Endurance training increase the proteins, enzymes and mitochondrial functions in human and animal samples. The purpose of this study was comparison of the influence of 12-week high-intensity interval training (HIIT) and moderate intensity continuous training (MICT) on PGC-1a and Tfam mitochondrial proteins expression in gastrocnemius muscle of elderly rats. In this study 45 elderly 22 months old Wistar rats (weighing 325-375g) were randomly divided into three groups: HIIT, MICT, and the control group. The exercise in the HIIT group was started with 20 minutes (2 minutes at 85-90% VO2max intensity and 2 minutes of recovery period at 45-50% VO2max intensity) in the first week and then reached to 48 minutes in the 12th week. The training program in the MICT group was begun with 20 minutes (at 65-70% VO2max intensity) and reached to 48 minutes in the 12th week. The expression levels of PGC-1α and Tfam proteins in gastrocnemius muscles were measured by Western blot method. One-way ANOVA was used to analyze the data. The PGC-1α expression was significantly increased in the HIIT (P< 0.001) and MICT (P<0.01) groups compared to the control group. Also, PGC-1α levels were significantly increased in the HIIT group compared to the MICT group (P<0.05). Tfam expression was significantly increased in the HIIT (P<0.01) and MICT (P<0.05) groups compared to the control group. HIIT resulted in a greater increase in PGC-1α and Tfam expressions in the gastrocnemius muscle of elderly rats compared to MICT.