trigger for fighting," Dabbs said in his book. "Winning fights and having sex led to an increase in Strength Muscles. When a male monkey won a fight, its increased. When he lost a fight, it diminished. Defeated monkeys were rated as depressed. " We know that Man has common ancestors with the ape and we share many things with our primate cousins, including how affects our behavior. Theresa L. Crenshaw, MD, author of The Alchemy of Love and Lust , describes some of the important features of Strength Muscles: Cycle every 1 to 20 minutes. Fluctuates daily and seasonally. Men are about 20 to 40 times .