px-r-F5cPQX9ZxUrwgORsMGDGwU Kuhnesiology: January 2012

Monday, January 16, 2012

Exercise...before you exercise

So it's been a while.  Sorry for the delay.  I hope everyone had an excellent new year.  I was very much under the weather...attempting to battle a tag-teaming virus and bacteria.  After a brutal week of not being able to eat...and losing 15 lbs...I'm finally back to "normal."

I've been bouncing this blog's topic around in my head for a few weeks, and finally decided to start from the beginning.  By that...I mean a proper warm-up.  I was taught, from a very young age, that before you exercise...you must warm up.  That meant a lot of static stretching.  Each stretch was held for at least 30 seconds, hitting all the major muscle groups.  It didn't matter what the activity to follow was going to be...lifting, running, basketball, etc...you had to stretch, right?  Maybe the warm-up included some jogging or a few minutes on the eliptical machine...but not too long, and not too intense...I mean, you don't want to waste your energy on the warm-up.

In my opinion, all that "traditional" stuff needs to go.  We all should have more common sense than that.  I mean seriously, does it make sense to do a 5 minute stretch session (low intensity) followed by 3-5 slow minutes on an eliptical (low intensity)..and then throw as much weight on the bench as we can possibly lift (high intensity)?  I would argue that there is a better way to prepare for physical activity.  I believe a dynamic warm-up is a better way to prepare the entire body for physical activity.  

What is the point of the warm up?
Well...if the goal of the warm-up is to adequately prepare you for the stress of exercise...we need to evaluate our warm-up.

What is the difference between a static stretching (traditional) warm-up and a dynamic stretching warm-up?  Lets see what the body of literature says.

A study performed at the U.S. Military Academy, West Point, by D.J. McMillian, J.H. Moore, B.S. Hatler, and D.C. Taylor compared the outcomes of a traditional "static" warm-up, no warm-up, and a "dynamic" warm-up prior to 3 tests of power and agility (T-shuttle run for time, underhand medicine ball throw for distance, and 5 step jump for distance).  The testing, which occurred over 3 consecutive days so that each participant in the study was tested after random assignment to each type of warm up, yielded significantly clear results.  Across the board, the dynamic warm-up resulted in significantly greater performance outcomes for each of the 3 tests when compared to a static warm-up or no warm-up.  The authors of this study, therefore, suggest that due to the performance outcomes of a dynamic warm-up, a traditional "stand-alone" static warm-up prior to physical activity should be reassessed.

A study looking at the specific effects of static stretching on peak torque (maximal force) production of the quadriceps sheds more light on the warm-up issue.  T.A. Siatras, V.P. Mittas, D.N. Mameletzi, and E.A. Vamvakoudis measured knee flexion ROM as well as isometric and concentric isokinetic peak torque of the quadriceps muscle group before as well as after static stretching in 4 experimental groups (no stretching (control), stretching for 10 seconds, stretching for 20 seconds, stretching for 30 seconds, and stretching for 60 seconds).  Though there was a significant increase in knee joint flexibility in the 30 second and 60 second stretching groups, these groups both also displayed a significant decrease in isometric peak torque and isokinetic peak torque.  In other words...when static stretching is used to "loosen-up" prior to physical activity...the result is actually a reduction in the muscle's ability to generate power.  That is not a very good trade-off if you ask me.  The authors go on to suggest that static stretching held for 30 seconds or longer should NOT be performed prior to performances requiring maximal strength.

Another study involving the effects of static stretching duration on the muscle force production brings to light an important concept.  J.P. Brandenburg conducted a study measuring 2 static stretching groups (15 seconds and 30 seconds) prior to hamstring performance during concentric, isometric, and eccentric muscle contractions.  The results revealed a reduction in performance in each muscle contraction type in both groups.  The author therefore concluded that regardless of duration of static stretching, even a very short stretch duration (15 seconds), there is a statistically significant decrease in muscle power production, and static stretching is consequently not appropriate as a warm-up prior to "strength activities".

So static stretching increases ROM prior to activity...but can cause reductions in power output.  I know what you are thinking:  "Dynamic stretching can result in better performance outcomes when compared to static stretching...but what effect does dynamic stretching have on ROM?"  I'm glad you asked...because E.T. Perrier, M.J. Pavol, and M.A. Hoffman have an answer.  In their study looking at the the differences between a static and dynamic warm-up on countermovement jump height, reaction time, and low-back and hamstring flexibility, the authors explain that though there was no significant difference between groups on reaction time, dynamic warm-up had a significantly greater performance outcome on countermovement jump height when compared to static warm-up.  This is the cool part (in my opinion)...both static warm-up and dynamic warm-up had a statistically significant increase on the outcome of the flexibility test...with no statistical difference between the two groups.  Meaning?  Well...it means that a dynamic warm-up is just as effective as static stretching at increasing ROM...while having no detrimental effects on power output.  That's a big deal!  The authors recommend, therefore, based on the results of this study, that individuals participating in activities requiring lower extremity power should employ a dynamic warm-up to improve performance and simultaneously increasing flexibility.    http://www.ncbi.nlm.nih.gov/pubmed/21701282

Those are some specific examples...but what is the collective consensus on the static vs dynamic topic?

D.G. Behm and A. Chaouachi conducted a review of literature on the acute effects of static and dynamic stretching and performance outcomes.  Though they explain that there are a large number of studies that show static stretch-induced decreases in performance prior to activity, there are also many studies that show no performance decreases associated with a static warm-up.  The authors explain that these newer studies showing no performance decrements may be due to specifics in the study protocols such as: stopping the stretch before the point of discomfort, the specific choice of performance test measure, the amount of time the stretch is held, and the specific population used (elite athletes as opposed to trained middle age participants, for example).  An interesting thing to note is that the authors state that there may be performance benefits to static stretching prior to activities that require "slower velocity eccentric contractions" and "contractions of a more prolonged duration or stretch-shortening cycle".  To conclude, the authors recommend that static stretching be used as its own separate component (not prior to exercise) for the specific "health related range of motion benefits".  Back to the issue of warm-up...the authors explain that in order to both enhance performance and minimize impairments, submaximal aerobic activity followed by "large amplitude" dynamic stretching and finally, if applicable, concluding with sport-specific dynamic movements and activities.

So when it comes to preparation for physical activity...static stretching doesn't cut it.  The takeaway:
-  Static stretching...regardless of the duration...results in performance reductions
-  Dynamic stretching is just as effective as static stretching at increasing flexibility and ROM prior to activity
-  Dynamic warm-up results in increases in measures of athletic performance when compared to static warm-up

Please don't get me wrong.  I'm not here to attack static stretching.  There is most definitely a time and place for static stretching...I just don't think it has any place in preparation for physical activity.  There are numerous health and flexibility benefits associated with this type of stretching.  I recommend using this modality after exercise or activity is finished.  My reasons for post activity static stretching may be a future post.    

Before I finish up, I just wanted to mention that there are many exercise professionals, including physical therapists and strength and conditioning coaches who have been in this industry much longer than I have, who include static stretching into a warm-up.  I can not speak for all of them, but I would assume some sort of dynamic movements are performed after the static stretching is used.  While I was examining this warm-up philosophy...I found this interesting study, one worth examining, involving static stretching followed by dynamic movements prior to athletic activity.  If static stretching is thought to be necessary prior to an athletic activity, K.L. Taylor, J.M. Sheppard, H. Lee, and N. Plummer explain in their study that the performance decrements associated with static stretching can be offset if it is immediately followed by a sport-specific warm-up component.

I try to include some sort of practical application in each blog post...but unless you already know what a dynamic warm-up entails...you may have to wait til the next post.  So sorry!  I'll go into what I do for my warm-up...and I may even have video examples.  Exciting...I know.

Stay tuned!


P.S.  I'm going to have guest blogs in the future.  For now, however, I may include bits and pieces of conversations I've had with fitness colleagues about specific blog topics.  Here is a piece my friend Lovell Thomas had to say regarding a proper warm-up:

"I believe your warmup should be based on the type of workout you are preparing for. So if you lift hard core I think the warmup should be pretty intense to get the muscles prepared to fire quickly. If you are just going to do a low intensity long distance run the warmup can be some static stretching and some active stretching to get the blood in the lower extremities flowing (adequate blood flow to the joints).  
With resistance training I usually suggest warmup your body accordintg to what you plan to workout. If you are doing an upperbody routine, a few sets with very light weight incorporating the actual exercise(s) or motions that you plan to use can be sufficient. Add some rotator cuff work (a common weak point) before getting too intense. If a lower or full body workout is planned, then i suggest only active stretching with rotator cuff work along with warmup sets for the first few exercises. These warmup sets must be thorough and progressive to avoid injury. Now Kuhn correct me or feel free to interject but i always save static stretches for the end of resistance training workouts because I believe elongated and over stretched muscles are more prone to injuries due to ligaments and tendons having too much "give" and reducing power output. (could be wrong) But more so use post workout stretching to prevent intense muscle soreness aka DOMS baby!!!"