While checking out some workout videos, I can across one from Jillian Micheals where she says, "you never want to do static stretches until after the workout is over and you're doing cool down".
Why does she say this? What is the problem with doing static stretches pre-workout vs dynamic stretches?
Studies (like this one http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1250267/) show that stretching does not prove to be useful before training at all.
To quote a commentary on the study i linked:
In view of the limitations of the review, the evidence presented here indicates that neither pre-exercise nor postexercise stretching positively affects soreness. This observation is consistent with the extensive body of literature on the treatment of postexercise muscle soreness, indicating that no nonpharmacologic intervention has a significant effect on soreness.
With respect to injury risk reduction, the authors have provided strong evidence from randomized trials that pre-exercise stretching of the major lower extremity musculature using a specific stretching protocol does not result in a meaningful reduction of lower extremity injury risk. However, because these investigators only studied army recruits, the authors stated it would be interesting to assess the effect of more prolonged stretching performed by recreational athletes over an extended time (ie, months or years) on injury risk reduction.
Some even say that stretching pre-workout lowering your max performance in strength training! I cant find those studies right now, but If you ask me, science says that stretching pre-exercise does not help prevent injuries or limit the DOMS one may experience after the workout.
So for the sake of your question, because we cant prove that stretching is useful, we can skip even without checking if it actually has some negative side effects, like Jillian Michaels suggests (and Im pretty sure it does).
This goes for pre and post-workout stretching, not stretching as a standalone. Im stretching too, but it serves diferent goals (I have too tight pectoral muscles and need to stretch them to help maintain good posture). I do both static and dynamic stretches to increase my range of motion and accustom some of my overtightened muscles to being in the neutral state, but I do it on non training days and in the morning.
Also, remember to do a proper warmup before doing any streneous exercises - warmups have been proven to be beneficial!
In order to answer this question we need look at the differences in these 2 types of stretching, let me explain.
Static stretching - is referring to when you are trying to increase the ROM (range of motion), an example would be a 1 leg hamstring stretch, as you sit and have 1 leg extended on the ground you would for a period of 30 seconds pull on your toes or ankle in order to stretch your hamstring, in other words increase the ROM, as oppose to,
Dynamic stretching - which is referring to when your body does the work for you, which in our case with the hamstring stretch, you would stand with 1 leg off the ground and you would swing that leg back and forward till you see that your hamstring has reached its fullest "current ROM".
I have quoted "current ROM" because that is the main difference between Static and Dynamic stretching, in the case static stretching as in the 1 leg hamstring stretch, within 10-15 seconds as you pull you would have reached your fullest "current ROM" whatever you do afterwards is trying to go beyond that, in Dynamic stretching all you are trying to achieve is your fullest "current ROM", in fact you would hear a lot of times trainers emphasize while doing Dynamic stretches not to over stretch, now that we know all that I will try to go over the reason for stretching and the effect it has.
Reason - The main reason for stretching is that while you are working out may it be in a strength program doing a bench press or a round house in a martial arts class, in both of these cases a certain muscle would have its ROM increased beyond its day to day ROM, in the bench press it would be chest (Pectoralis major), and in the round house kick it would primarily be your hamstring, having said that, not making sure before a workout that your body is ready to go to that ROM and usually because you have not warmed up enough can cause you to pull a muscle or even worst.
Effect - The effect stretching has on your muscles (besides for the obvious which is increasing ROM) is in fact counter productive, mainly in strength workouts and that is because muscles are at its strongest while they are contracted and tight in a bench press while your hands are extended upwards or in a bicep curl while your hands are curled up, so the more you increase the ROM the more your muscles are weakened and therefore you will be unable to fully perform while working out, and that is why there are people who don't stretch at all before a workout, now here is the big "revelation" this counter productive effect is mainly only in "static" stretching and that is because as we said in "dynamic" stretches you are not trying to increase your overall ROM.
I hope i have answered your question as to why Jillian wants you to avoid statically stretching before a workout, I know that there is a lot more to stretching for example hormone releases, but for its not for this article.
I should point out a few things.
static stretching is OK before your workout if don't pass the 10-15 second mark in other words don't try to go to the beyond, and it is common to do them as well as long its not over done, an example would be Tony Horton in P90X in which he does a combo of dynamic and static stretches before the workouts.
I'm not sure why Jillian is trying to avoid static stretches so strongly since to my knowledge her workouts are mainly cardio but I might be wrong on that, let me know DustinDavis.
I remember reading about this topic a while ago.
I don't remember the exact articles I read, but the upshot was this: static stretching BEFORE strength/explosive movements is at best irrelevant and at worst actually decreases performance.
Here is a page with a summary of a few different studies that seem relevant: http://www.brianmac.co.uk/articles/article027.htm
With that being said, I do think there is something you should do before any workout - and that is warm up - especially if we're talking about heavy lifting or explosive movement. Stretching seems to me to be a somewhat misguided attempt to 'loosen up' the muscles before working them, in the hopes of preventing injury, when what you really want is a good warmup.
Here is a good article from Joe DeFranco on the whole subject: http://www.defrancostraining.com/articles/38-articles/58-the-stretching-roundtable-2.html
Not exactly a scholarly article, but DeFranco trains some very strong people professionally and I think his thoughts are well-grounded in real-world experience.
It's a bit of a contrived comparison, but if you think of your muscles as a kind of elastic material, like a rubber band for example, the whole warmup concept is a bit more intuitive. Would you rather put a lot of stress and force on a rubber band that has been taken out of the refrigerator 2 seconds before, or one that has been flexed gently for a few minutes until it is more pliable?
I also remember reading that if you do want to do static stretching, you can feel free to do it post-workout - when your muscles are still warm (so you can actually stretch farther) and so that you don't have to worry about any performance degrading (your workout is over anyway).
This blog kind of sums it up nicely: http://www.mindthesciencegap.org/2013/04/04/a-muscle-myth-buster-stretching-and-physical-performance/
