From here and other places around the internet, the Bill Starr rehab protocol for muscle-belly injuries is described like this:

Wait 3-4 days until the pain starts to “blur”, which indicates that the immediate process of healing has stopped the bleeding and has started to repair the tissue. Then use an exercise that directly works the injury, [...] in this case the squat. Use the empty bar and do 3 sets of 25 with perfect form, allowing yourself NO favoring the injured side. If it’s ready to rehab you will know by the pain: if the pain increases during the set, it’s not ready, if it stays the same or feels a little better toward the end of the set, it is ready to work.

The NEXT DAY do it again, and add a small amount of weight, like 45 x 25 x 2 , 55 x 25. Next day, 45 x 25, 55 x 25, 65 x 25. Continue adding weight every day, increasing as much as you can tolerate each workout. It will hurt, and it’s supposed to hurt, but you should be able to tell the difference between rehab pain and re-injury. If you can’t, you will figure it out soon enough. This method works by flushing blood through the injury while forcing the tissue to reorganize in its normal pattern of contractile architecture.

After 10 days of 25s, go up in weight and down in reps to 15s, then to 10s, and finally to fives. During this time do NO OTHER HEAVY WORK, so that your resources can focus on the injury. You should be fixed in about 2 weeks, squatting more than you hurt yourself with.

This method has the advantage of preventing scar formation in the muscle belly, since the muscle is forced to heal in the context of work and normal contraction, using the movement pattern it normally uses. The important points are 1.) perfect form with 2.) light weights that can be handled for high reps, 3.) every day for two weeks, and 4.) no other heavy work that will interfere with the system-wide processes of healing the tear.

It is also very important through the whole process of healing the injury that ice be used, during the initial phase after the injury and after the workouts. Use it 20 on/20 off, many times a day at first and then tapering off to morning, after the workout, and before bed. Ice is your best friend in a muscle belly injury, holding down inflammation and fluid accumulation (“swelling”) while at the same time increasing beneficial blood flow through the injury. But DO NOT USE ICE MORE THAN 20 MINUTES AT A TIME. More than that can cause more damage than it repairs.

This may actually be the most useful post on this entire little forum of mine, and if you use this method exactly you can save yourself many weeks of lost training and long-term problems with muscle-belly scarring.

(I don't know if I've pasted too much, but I thought it's useful for this question.)

My questions:

  1. Is there a controlled study that compares full rest (no activity, just icing), vs active recovery (stretching, massaging, foam rolling, range of motion work), vs loaded recovery (this protocol)?
  2. Is there actually a danger that the muscle will heal improperly if you don't work it under progressively heavier loads during recovery? (I know this protocol claims this is the case.) I'd be happy with just some pointers to other evidence that this is the case.
  3. Does this protocol prevent scar tissue formation? (Again, I know it claims to.) A good answer would talk about how scar tissue forms after a muscle belly injury, and how movement, or movement under load may prevent it (or not prevent it).
  • I doubt there's a study, but this is a great area of inquiry. Wandering Rip's forums gives a ton of people who say, anecdotally and with plenty of placebo potential, that the protocol helped them. Commented Nov 28, 2012 at 23:04

2 Answers 2


Regarding a controlled study of this particular rehab protocol, you won't find one. The problem is that there are several rehab protocols, and as long as it is founded on rational principles they all will work.

However, in regards to scar tissue formation, you will find many resources, including a short article on Medical News Today:

  • When the body is injured it sends fibroblasts to the area.
  • Initially it grows within the clot to help stop the bleeding and connect the two sides of the tear
  • The fibroblasts grow stiffer over time, and eventually contract to pull the sides together.

A quote from the article may shed some light on the subject at hand:

The reported research reveals for the first time that a mechanical mechanism is crucial for this switch from migrating to contractile cells. To make this change, the fibroblasts need to get at their "spinach" -- the growth factor sitting in the matrix which, once liberated, stimulates the production of smooth-muscle proteins. Previously, researchers postulated that the fibroblasts did this by digesting the matrix. But EPFL scientist Boris Hinz, doctoral student Pierre-Jean Wipff and their colleagues have discovered that the cells unlock the growth factor via a purely mechanical process.

Referenced Paper: Pierre-Jean Wipff, Daniel B. Rifkin, Jean-Jacques Meister and Boris Hinz, "Myofibroblast contraction activates latent TGF-b from the extracellular matrix", Journal of Cell Biology, December 17, 2007.

Another less scientific article on LiveStrong also sheds some light on the subject. Essentially, part of the healing process is regaining full range of motion as soon as possible. There are further references at the bottom of the article if you are inclined to read more.

Applying This Information to the Bill Star Rehab Protocol

Considering that scar tissue is formed through natural healing processes using the fibroblasts, and that full range of motion in the injured area helps the fibroblasts do its job more efficiently, the only thing left is to define full range of motion for your muscle-belly. Squats, being a full body exercise do get just about every muscle involved.

However, there is a balance. Obviously, you do not want to re-injure the area. Just about every rehab protocol I have seen features very high reps at very low weights. The purpose is to get blood flowing though the area which does two things:

  • Flushes out inflammation, fluids, and repair byproducts
  • Provides fresh oxygen, blood, etc. to the area

The combination of the mechanical motion of the light weight squats, and the blood flowing through the area provides favorable conditions for minimizing scar tissue. The important aspect is to just do the rehab protocol and no other work until. Heavy work too soon will re-injure the area.

  • Excellent point about how high-repetition, low-weights positively impact muscle health. In addition, make sure the repetitions are slow and controlled.
    – BryceH
    Commented Dec 21, 2012 at 20:02
  • Anecdotally, I can add that doing light weight squats (just the bar even) are terrific for getting blood moving around and getting through few-day-old injuries. You just feel good doing them, and it's so much better than complete rest.
    – Eric
    Commented Dec 23, 2014 at 6:28

I really want to answer this question with 100% confidence but I can't find the evidence to back it up. This is the best I can do...

1) There are individual studies about each of the recovery methods you inquired about; but, no study (that I can find) directly comparing the two. Each of the recovery methods are valid in their own right. Everyone is different though, and all of the methods won't work wel lfor each person.

2) To the best of my knowledge there is not any danger the muscle will heal improperly. The risk you run by not (at the very least) actively stretching the affected muscles is a loss in range of motion.

3) On page 222 in the book "Skeletal Muscle Repair and Regeneration By Stefano Schiaffino, Terence Partridge" Click here It shows exactly how scar tissue is formed during the repair of skeletal muscle. However, lifting doesn't cause complete transverse tear of the sarcomere. Lifting causes a breakdown in the muscle, not a complete rip. Therefore I do not believe scar tissue is formed during weight-lifting unless you happen to completely tear the muscle you are using.

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