Why Shoulder Rehab Should Be Like A Delicious Pizza

Rotator Cuff Related Shoulder Pain Rehab Should be Like a Good Pizza

Rotator Cuff Related Shoulder Pain Rehab Should be Like a Good Pizza

Okay, this is the pizza blog and you’re probably thinking: How is a pizza related to rotator cuff related shoulder pain?

In fact, the pizza model is a great analogy for the rotator cuff-related shoulder pain rehab.
And although this analogy is of course too simplistic to be transferred to all variables in human beings, I believe it’s a very good way to memorized complex knowledge.

1) Dough = Education

So, in the analogy of a pizza – first there is the dough, which i would like to compare to Education.
The basis of your rehabilitation strategy is education. There is no pizza without a dough. There is no rehabilitation strategy  without educating your patient. And okay, I acknowledge that there are different types of dough – there are also different ways of educating your patient.  Your patient will have other experiences and different knowledge about the problem, so also your education will be different in different patients.

Pizza dough
Tomato saus

2) Tomato saus = Healty lifestyle

Second in a pizza is the tomato saus and this is your advice for general fitness. Run, walk, bycycle – this is probably the healthiest part of a pizza, but this is also the healthiest part of your rehab program. Take advantage of your patient being in your practice to advise them to be more fit in general. This doesn’t only mean to prevent other co-mobidities, but also has an influence on your pain perception for instance.

3) Cheese = Progressive loading program

Third, you got the mozzarella/cheese. This will be your progressive loading program of the musculotendinous unit of the rotator cuff and also what really makes the pizza delicious.
And actually, you now have all the ingredients for a pizza Margherita – which is the most popular pizza world-wide by the way. You got your education, healthy lifestyle advice, and a progressive loading program.


4) Ham = Manual Therapy

But okay, but you can also pimp your pizza with ham for example. We could compare the ham to manual therapy. It’s not always necessary for all patients, but in some people adding ham can encourage your patients to eat it or in other words to motivate him/her to follow the progressive loading program you design for him/her.

5) Mushrooms, Onions etc. = Massage, Dry Needling, Taping etc.

At last, we could add mushrooms  or onions for example. This might be of added value: It’s completely again optional, but can convince your patient to eat the pizza, but absolutely not mandatory. I compare these extra ingredients to dry needling, massage, shockwave, taping etc.


6) Pineapple = Therapeutic Ultrasound, Laser etc.

Okay, we have to talk about pineapple of course. In my opinion, pineapple doesn’t belong on a pizza and you could compare it to your therpeutic ultarsound machine – in other words, it’s useless for your treatment success.
P.S. Physiotutors agree with the fact that ultrasound & laser doesn't belong in shoulder rehab, but a good pizza Hawaii can actually be very delicious!;)

Now this was a very rough overview about how a delicious pizza relates to rotator cuff related shoulder pain rehab. Maybe I could spark your appetite for pizza and you would also like a recipe on how to actually “bake” such a delicious pizza. All the details can be found in my newly released online courses Rotator Cuff Related Shoulder Pain: Separating Facts from Fiction.
If you would like to have a better idea of what you can expect in the course, either head to the following info page or feel free to subscribe to my FREE 5-day video-course below!

Thank you very much for reading!



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Kaltenborn’s Concave-Convex Rule – Flawed or Just Misinterpreted?

Kaltenborn's Concave-Convex Rule - Flawed or Just Misinterpreted?


The concave-convex rule by Freddy Kalternborn is taught in many physio school throughout the world and chances are high your have learned it too. But does its concept stand the test of time and evidence or is it flawed like many other concepts?

The rule in a nutshell

Schomacher (2009)

The concave-convex rule by Kaltenborn tells us which part of the joint capsule is stressed when we move an adjacent joint partner:

When a convex joint surface is moving, the roll and glide occur in the opposite direction.

When a concave joint surface is moving, the roll and the glide occur in the same direction.
You can watch a video in the top right corner in which we cover the concept in more detail

Kaltenborn used this knowledge of arthrokinematics to determine the appropriate direction of translational glide in order to determine which part of the joint capsule should be mobilized. But is it really that simple?



Does roll and glide happen in a joint according the rule?

Bayens et al. (2000) examined joint kinematics of the glenohumeral joint in the late preparatory phase of throwing and they found that glenohumeral joint does not act as a ball-and-socket joint. In their study, the humeral head actually translated posteriorly in the late cocking phase – contrary to what we would expect. There is more evidence showing that roll and glide in a joint does not seem to follow the Kaltenborn rule: Scarvell et al. (2019)  found that knee flexion was actually coupled with a posterior translation of the femoral condyles – contrary to what we would expect based on the Kaltenborn rule. The same is true for another study of Bayens et al. (2006) where they found a posterior translation of the radial head during supination in the proximal radio-ulnar joint, while the convex–concave rule predicts anterior gliding of the radial head. How can those findings be explained?

Schomacher (2009) argues that we should not forget that the humeral head is rolling posteriorly in the late throwing phase which will of course move the humeral head posteriorly. The net translation of the humeral head in this study is only a few millimetres. To put this into perspective, consider an adult-size humeral head with a circumference of 16 cm. A motion of 90° of GH joint abduction occurring purely due to a rolling motion (with no concurrent anterior glide at the articular surface) would theoretically cause the humeral head to just roll of the glenoid about 4 cm. Clearly, a significant, concurrent anterior glide of the humeral head must occur and the fact that the humeral head moves only a couple of millimetres is proof of a significant glide. So despite the results of Bayens, there is no contractiction to the Kaltenborn rule. In order to really say something about rolling and gliding, we have to differentiate between movement of the center of the head of the humerus and the movement of the joint surfaces, for example with dynamic radiographs.


Does the rule tell us which in which direction we have to mobilize?

Let’s look at a study by Johnson et al. in (2007) who used the concave-convex rule to increase external range of motion in patients with frozen shoulder:
Based on the the concave-convex rule of Kaltenborn the authors argued that in external rotation of the glenohumeral joint, the convex part (head of the humerus) will glide anteriorly, while it will roll posteriorly on the concave part (in this case, the glenoid) – similar to the reasoning we have for the apprehension test.

So what Johnson and colleagues reasoned that – following the Kaltenborn rule – they would have to perform posterior to anterior glides in order to increase external rotation. So one group performed PA glides, while the control group performed joint glides from anterior to posterior, so AP glides. The results were surprising as the PA intervention group improved external rotation by just 3 degrees, while the AP control group improved external rotation ROM by 31.3°

Although the PA group was mobilizing according to the Kaltenborn rule, the posteriorly directed joint mobilization technique was more effective than an anteriorly directed mobilization technique for improving external rotation ROM in subjects with adhesive capsulitis. Both groups had a significant decrease in pain.

Our takes on this study is first of all that we're wondering if external rotation is rather a spin movement in the joint than an actual roll and glide movement. We would rather expect a pure roll and glide in horizontal abduction. Second of all, Neuman (2012) points out that the convex-concave rule was never intended to establish the direction of a manual glide, applied at a joint, that would best increase a targeted movement. The rule merely describes the arthrokinematic pattern that minimizes the inherent migration of the center of the convex member in the direction of the roll.
Physiotherapist should not mobilize a pathological joint according to a rule, but treat pathological clinical findings, which are in correlation with the patient’s complaints. Neuman argues that perhaps the capsular tightness associated with the patients’ pathology caused the humeral head to migrate to a more anterior resting position than normal relative to the glenoid. The use of a posterior glide might have preferentially stretched parts of the capsule, allowing the humeral head to be more centralized relative to the glenoid. This new position might, in turn, have partially unloaded the anterior capsule, thereby allowing greater external rotation. Without objective data on which part of the capsule was most restricted and the position of the humeral head at the start and end range of motion, this scenario is purely a speculation, and others are possible.

The questions is: Can we even influence a joint capsule given that join mobilization only happens in the toe phase when we have a look at the stress-strain curve of collagen?
We might be able to create a little bit of creep if we hold the mobilizations at end-range, but as often with manual therapy, the effects are probably neurophysiological. That could also explain why it is probably less relevant which part of a certain capsule is stressed.

Bogduk (2005)


Is the Kaltenborn rule just misinterpreted?

Okay, let’s sum it up: Is the Kaltenborn concave-convex rule flawed or just misinterpreted? No, it still describes arthrokinematic movement in terms of role and glide in a joint. Can it be used to determine into which direction we have to mobilize in order to improve a specific osteokinematic movement? Probably less so. The rule might be a starting point, but for each patient we will have to assess limitations in range of motion and roll and glide individually, thereby keeping the low reliability in mind. Given the evidence on the working mechanisms of manual therapy it might be irrelevant which part of a joint capsule we are stressing as stretching a capsule is probably not possible and the effects on pain and increased range of motion are likely be achieved through this neurophysiological mechanism.



Baeyens JP, Van Roy P, Clarys JP. Intra-articular kinematics of the normal glenohumeral joint in the late preparatory phase of throwing: Kaltenborn's rule revisited. Ergonomics. 2000 Oct 1;43(10):1726-37.

Baeyens JP, Van Glabbeek F, Goossens M, Gielen J, Van Roy P, Clarys JP. In vivo 3D arthrokinematics of the proximal and distal radioulnar joints during active pronation and supination. Clinical Biomechanics. 2006 Jan 1;21:S9-12.

Neumann DA. The convex-concave rules of arthrokinematics: flawed or perhaps just misinterpreted?.

Schomacher J. The convex-concave rule and the lever law. Manual therapy. 2009 Oct;14(5):579.

Johnson AJ, Godges JJ, Zimmerman GJ, Ounanian LL. The effect of anterior versus posterior glide joint mobilization on external rotation range of motion in patients with shoulder adhesive capsulitis. journal of orthopaedic & sports physical therapy. 2007 Mar;37(3):88-99.

Scarvell JM, Hribar N, Galvin CR, Pickering MR, Perriman DM, Lynch JT, Smith PN. Analysis of kneeling by medical imaging shows the femur moves back to the posterior rim of the tibial plateau, prompting review of the concave-convex rule. Physical therapy. 2019 Mar 1;99(3):311-8.


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