We have periodized running/swimming/biking/weight training, and periodized diets. Why don't we periodize our stretching and warm-up routines as well? There is quite a bit of controversy when it comes to stretching. Does it not make sense to periodize your stretching and warm-up routine?
During your less intense base period stretching can be somewhat more static in nature with stretches being held for 10-15 seconds in duration. Performing these types of stretches before and after training is ideal. Foam rolling can also be incorporated into your warm-up along with 1 or 2 core movements (I like the plank, chin-up, or push-up). I usually follow the core activation phase with a short plyometric phase just prior to my main training set of running, cycling or weight training. As you progress through Base I to Base III training phases slowly reduce your stretching hold times until you are only holding your stretch for 1-2 seconds by your final Base III phase. You can slowly increase your activation exercises and plyometric warm-up as you progress through your Base I - III phases. Remember though to do very little plyometric warm-up and always step down off the box if doing box jumps. I never go over 25 box jumps in a single warm-up session and always precede box jumping with some light rope jumping. I feel that for masters level cyclists and triathletes this little extra plyometric activity pays big dividends as the season progresses by maintaining power levels on the bike and continually reminding the legs of that extra stress they receive in competition.
BUILD I & II
During your more intense build I and II phases of training your stretching can be more dynamic in nature with stretches only being held for 1 second or less. I know many physical therapists like holding a stretch for about 1-2 seconds as this reduces the micro tears in the muscle fiber. See what works for you.
As you progress through your build I and II phases your stretching routine in both your warm-up and cool down periods will become more and more dynamic until you are ultimately performing leg swings, arm swings, and isolation stretching of about 1 second. Definitely avoid long holds at this point in your training and use the extra time available due to shorter holds in order to hit more and more body parts.
This sounds like a great deal of time but in reality you can foam roll, stretch out and activate your muscles in about 15 minutes if you really get to it. Avoid over stretching in all phases but especially in you build I and II phases.