On a recent episode of Super Human Radio I interviewed Dr. Bob Buresh about his study on rest intervals and their effects on hormonal response to exercise. While this study attempted to unlock the ideal between-sets rest interval to evoke the greatest growth and strength provoking hormonal response, something else was discovered. Five weeks may be the ideal period of time to change your training program to 
avoid plateaus and provoke continuous growth!
Other studies have looked at untrained acute response to varying rest intervals however Dr. Buresh’s group looked at the prolonged effects in trained subjects over a longer 10 week period. Subjects were given a specific resistance training regimen to follow that allowed the to complete their workout in under an hour, three days a week. The one variant between the two test groups was the rest interval between sets. One group rested for one minute and the other for two and a half minutes.
It was no surprise that the one-minute rest group experienced the greatest initial hormonal response with a significant rise in testosterone, growth hormone and cortisol. What was most interesting is that at the five week period both groups experience the same hormonal response.
Five weeks may be the time to change your training style to evoke new growth. While most periodized training programs use the calender quarter as the training style period, Dr. Buresh’s study may show this is unnecessarily long. The body may adapt to your current training style and this may lead to a plateau.
Carl Lanore is the host of Superhuman Radio, a weekly radio show dealing with physical culture. He has been published by Muscle Evolution (South Africa), and MuscularDevelopment.com (United States). 