Strength training: rest between sets
If your training heavy, working to improve your strength you will most likely be working with 80% upwards of your 1 rep max and be keeping your reps low and sets high. The problem is a lot of people think even though they are working with near maximum loads they can still take 30-90 seconds rest and still hit your reps for that set. Unfortunately most of the time this just isn't the case. When working with 80%+ of your 1 rep max your are using, for the most part, a different energy system compared to let's say hitting 8-12 reps to trigger hypertrophy. Because of this and how taxing lifting with near maximum loads is on your muscles energy system, your rest intervals have to be altered to ensure your fully recovered and ready to hit the next set with everything you have. The effect this type of lifting has on the central nervous system alone requires you to be more strict with your rest periods. On average you are going to want to take 3-5 minutes rest to allow Adequate recovery. That being said, if you feel like you need more time to physically and mentally to recover before you smash some more iron then take as long as you need (within reason). I hope you can take something away from this short rant.