When you are doing crunches, hold your tongue on the roof of your mouth during the duration of the crunches. It may seem silly, but when you do this, your head will align properly during this exercise. Using this method, you will greatly lower the strain on your neck while performing crunches.
To help you recover faster from a hard workout, try giving the muscles a workout the following day. You should do this lightly, with about 20 of the weight that you can lift one time. Try to do 25 repetitions in two sets. When you do this, you will have more blood and nutrients delivered to the muscles for faster repair.