Muscle Response to High Intensity Interval Resistance Training (HIIRT)

Effects of Exercise Intensity and Rest Intervals on Intracellular Signals and Anabolic Response of Skeletal Muscle to Resistance Training

Resistance training (RT) is one of the most important stimuli for muscle hypertrophy and it plays an important role on weight loss and fatty acid oxidation increase. RT affects anabolic pathways but the differences among various training techniques has been till now were poorly investigated. The aim of this study was to compare the effect of two different intensity of training, high-intensity interval resistance training (HIIRT) and traditional resistance training (TRT), on muscle signalling pathway.

Nine young healthy subjects performed HIIRT and TRT protocol in two different moments and with different legs. HIIRT technique consisted of three sets of: 6 repetitions at 6RM (6 repetitions maximum) and then 20 seconds of rest and 2/3 repetitions (until exhaustion) repeated for 3 times with 2'30" rest between sets; while TRT consisted of 3 sets of 15 reps with 75 sec of rest between sets. Biopsies from the vastus lateralis were taken at baseline (pre), immediately (0h) at the end of training, 6 hours (6h) and 24 hours (24h) after training. Western blot and RT-PCR mRNA (Reverse transcriptase-polymerase chain reaction) analysis were performed to assess muscle signalling pathway activation

Inclusion Criteria:

• moderate active
• experience with resistance training

Exclusion Criteria:

• history of recent myocardial infarction,
• severe cardiac arrhythmia,
• unstable angina,
• poorly controlled hypertension,
• poorly controlled diabetes mellitus,
• frequent or complex ventricular ectopy which might interfere with one's ability to adhere to exercise protocols