The idea Pre-workout is to keep the body in a anabolic state while working out, when your breaking proteins down (catabolic state). Which is why it is important to consume High protein (for your body to use instead of muscle protein to remain anabolic) and Complex Carbs (to energize your workout and feed muscles). If done correctly, your body should remain anabolic for the next hour or so until your next high protein, simple carb meal to fully replenish glycogen stores. In the mean time- Growth hormone is spiked directly after working out maximizing the time it is being released due to no/small insulin release from the carbs.

Whey directly after working out is good but I recommend eating WHOLE food about an hour pre-workout high in protein and moderately high in complex carbs to maximize the hormonal and nutrient windows directly post-workout and to keep your body from breaking any hard earned muscle down to adapt to its current situation. Carbs, indirectly act as the "driver" for the proteins to reach your muscles. Whey directly after working out (when your body has ALREADY broke a bunch of muscle protein down due to resistance training) will help, dont get me wrong, once you get those carbs to "drive" the protein to cells… but the same carbs inhibit growth hormone release as well. Which is why pre-workout nutrition is so important.