Primal Growth If you have questions about precisely how push ups make the muscles grow, then learning know the essential rule of muscle gain and which is - training against increasing resistance. Folks think how they only produce the resistance by lifting or pulling pounds. Yes, lifting weights is one the simplest way for creating resistance nevertheless the other excellent method is to using your own body strength. In place of external free weights or machine weights you can use your own body weight and create resistance training course. Push up is one such create.