Yes, I've read many contradicting studies about stretching when you are experiencing soreness from micro tears to the fibers. I don't know what is true and what is not about this subjuct anymore.

Advantages of cold is to reduce pain and swelling following an injury and up to 48 hours afterwards. You would not want to add heat after an injury because that will just aid the swelling and cause major problems. Swelling
(or edema) is necessailty helpful for healing. Another reason for using cold after and injury is to reduce the amount of tissue movement in the area.

So heat therapy should only be used to increase blood flow when you have an injury where there is no swelling?

But still, white blood cells cause the swelling, don't they? By "leaking" out from the blood vessels to the inflamed area where they kill germs and stuff. Why would you want to hinder this process? That's what I don't get..

I'll get to your 2nd question first, because it kind of addresses the previous. Ice constricts blood flow, that is correct. And it is also necessary when dealing with the majority of bruising/tearing type injuries (sprains/strains), because when you sprain or strain something, you've essentially torn tissue asunder allowing blood to flow and pool into places it's not supposed to, and when coupled with your bodies blood pressure, increased swelling and possible further tissue damage occurs. While heat aid in circulation necessary for tissue repair, it causes blood flow to increase to the targeted area, which can and will increase swelling, as the blood is no longer retained to capillary beds at the site of the swelling and injury, meaning that it is still spilling into the affected tissue.

Applying cold to the area prevents excessive swelling, and if the injury is treated quickly enough, and isn't anything beyond a moderate sprain/strain, can actually prevent some swelling altogether. And you are correct that you should apply cold in managed intervals. This allows for an organized constriction of blood flow, preventing any more swelling during the 15-20 minutes when cold is applied, but also allows for necessary circulation required for tissue repair (when taking a rest from cold application). The amount of cold application can vary by region and amount of injury/swelling, but at a minimum, you should be applying cold for at least 20 minutes every hour, and at most I'd say apply cold for 10 minutes on, 20 off, to prevent tissue damage due to freezing.

A good rule of thumb is to apply cold until swelling is gone, then apply heat for 20 minutes every hour in order to promote circulation and ease pain. For minor sprains/strains, swelling can last for 48 hours up to a week, For grade 2 and 3 strains/sprains, swelling and injury can last weeks to months (with most grade 3 injuries requiring surgical repair to the affected tissue). As long as there is swelling, I'd avoid heat therapy. I'd also avoid stretching at this point as well as you will warm the muscle and promote circulation, which should be put off until swelling receeds.

Because you're generally causing more harm than good in this situation. Excess swelling only causes more damage.

White blood cells still do their work within the swollen area, even with cold applied. Not to mention that the application of cold may essentially slow the progression of germs at the site of injury as well.

The key is preventing further injury caused by swelling, and preventing a cycle in which more circulation is required to repair an increasingly larger area of damaged tissue (spurred on by swelling).

So the reason we want to constrict bloodflow is because we don't want fluids to go where they shouldn't be? Obviously, fluids being where they shouldn't be isn't good.

So heat comes into the picture when the swelling is gone to improve circulation and thus repair?

Now this is all for injuries, but why no heat treatment for DOMS? DOMS doesn't make you swell up, does it? Or was the heat thing just for alternating heat and cold, like doing contrast showers (which are often recommended) because it ruptures capiliaries?

the ice is strictly to reduce imflammation

There's a large amount of research done on this subject right now, much of which is as inconclusive as the older research.

I tend to rely on the theories involved here, as I don't believe that there is any way to honestly have a control group here, as every individual's reaction to exercise (and resulting tissue damage), not to mention pain thresholds, are different.

The theories are fairly sound: exercise causes microtears, which leads to DOMS and tissue regeneration and adaptation, stretching aids circulation and keeps muscles warm, increased circulation aids in tissue repair (as long as there isn't swelling), promoting muscle repair more quickly.

I feel like this is going to be one of the red herrings of the exercise science world for a while to come, until the scientific method allows for qualitative analysis of the rate of tissue repair and adaptation, based upon the individual studied.

The no-heat thing is just for the alternating hot/cold treatment. As far as I've read, DOMS has no intertissue swelling and shouldn't require cold treatment, so the stretching and heat therapy should be used to promote circulation.

When you say stretching, do you mean stretching after a workout, or stretching throughout the day/days you have DOMS?
If stretching keeps your muscles warm and improves bloodflow, then surely the short time after a workout these factors are improved are very short.

And one simple way to figure this out would be to use the same people in the control group as the other group. Do squats, stretch one quad but not the other. Now, of course, there could be differences between the two muscles, but I bet it would be way better than comparing different people!

I've not read anything as to whether or not you can prevent DOMS in any way, and I don't believe that stretching immediately after a workout can affect this. Stretching immediately after a workout is really more for preventing inter/intra-muscular blood pooling and swelling by cooling down muscles in a controlled fashion, which is more for preventing immediate post-workout injury and swelling.

I definitely like your research idea though... now only if I had a PhD and a huge grant to make it happen .

lol, I never should have told you the idea, should have waited until I am to write my masters (if I ever will)

However, it has been done before, though not as a means to figure out a way to minimize doms (that I know of) In a study I read people walked down stairs, one leg at a time. With their right leg they went over two steps in one go and with the left leg they just took one step, then they compared DOMS in the two groups. The study was to figure out if the length of the eccentric made a difference to DOMS. (soreness in the supporting leg, of course, the one that does the eccentric) The research was about the "popping sarcomere hypothesis" quite interesting.

Just in case your interested: http://www.apps.org.au/Proceedings/34/19-23/19-23.pdf

Awesome read, thanks!

No problem! I find that hypothesis to be quite interesting. Maybe our muscles adapt quickly to what length we use them at..

Now what I have been thinking about is this: IF the popping sarcomere hypothesis is true, and doing eccentric exercises with large ROM will cause the muscle to increase the number of sarcomeres in series, would that lead to a muscle that is more flexible? Could this then be used to fix posture. For example, could someone with very tight pecs do eccentric DB flyes to increase the flexibility of his pecs and thus help him keep his shoulders back?

I don't know how numbers of sarcomeres in series relates to how flexible, moble, etc a muscle is. But I have heard that the reason we get for example "tight" hip flexors when we sit is because the hip flexors cut sarcomeres in series in order to adapt to them so often being in a shortened position.

from: Mike Robertson's Blog: October 2008

looks like you over did it for the first time coming back... you will heal!