Dr. Jared Powell:
Welcome back to the Shoulder Physio Podcast, episode 64. This is the show where we dig into the research behind various musculoskeletal conditions. We try and cut through the dogma and attempt to give you something to think about, not just another slogan to repeat. So today's guest is Tim Cook. Tim is a senior lecturer in physiotherapy at the University of Chichatsa, where he's been since 2021, and he also works as an advanced physiotherapy practitioner in the NHS.
Dr. Jared Powell:
He's a chartered physiotherapist who's been treating patients full-time across both the NHS and private practice since he graduated all the way back in 2006. So he brings nearly two decades of clinical experience to this conversation alongside his academic work. Tim is also pursuing a PhD exploring the specifics of strength testing for rotator cuff-related shoulder pain. Now, Tim is the lead author supported by Jeremy Lewis and myself on a new paper titled Rethinking Strength Testing in Rotator Cuff-Related Shoulder Pain: A Clinical Tradition That Lacks Muscle, just published in the Journal of Manual and Manipulative Therapy. It's a provocative piece. We ask whether strength testing in rotator cuff-related shoulder pain earns its place in clinical practice. Is weakness a cause of shoulder pain, a consequence of it, or an epiphenomenon? Does measuring strength change or guide our rehabilitation specifically? And are we clinging to maximal isometric dynamometry more out of habit than clinical necessity?
Dr. Jared Powell:
So this is just a broad outline of where we're heading in today's conversation with Tim Cook. Without any further delay, I bring to you my conversation with Tim Cook. Tim Cook, welcome to the show. Thanks,
Tim Cook:
Jared.
Dr. Jared Powell:
Real privilege to have you here. We've been working on a paper together for, I don't know how long, Tim. I can't remember how long it took. It always seems like these things take years from seed of an idea to getting it published, but we've had it published. The title of the paper is called, , let me check. Yeah, here we go. Rethinking Strength Testing in Rotator Cuff Related Shoulder Pain. A Clinical Tradition That Lacks Muscle. What a good title. All right, Tim, so that's gonna form the basis of our conversation today, but before we get into that, can you introduce yourself to the audience, please? Yeah, of
Tim Cook:
Course. Thanks, Jared. Thanks for having me on. Big fan of the podcast. So I'm Tim. I'm a musculoskeletal physiotherapist by background. , I work in the NHS in Sussex. I'm also a, a lecturer and a doctoral researcher at the University of Chitchester just down the road. Qualified back in 2006, I think it was, up in, , Bruno University, up in West London. Had a great time out there. Outside of work, keen rugby fan. I still, for my sins, , try and train once a week and occ - very occasionally play if my wife lets me. We've got three kids, so they keep, keep me busy, which is great fun, and it's great fun seeing them getting into all different sports at the moment. My, they're all big football fans, soccer fans, so we're watching the World Cup semi-final later on today. Mm. England, Argentina. Huge. Huge.
Tim Cook:
Yeah. So it's very exciting in our household.
Dr. Jared Powell:
Love it. Well, you and I have been talking for a while about rugby before this, so we won't bo- bore any of the listeners about it. I assume you're big England fans in the football/soccer?
Tim Cook:
Of course. Yeah. Yeah. Well, my wife's Irish. Yeah. , Unfortunately, Public Live Island didn't, didn't make the, , the World Cup this year, so she's supporting England. Great. , She seems to be supporting England. She's great. She's, , she's, she's glued to
Dr. Jared Powell:
It like the rest of us. Good. Well, best of luck. I'm a messy fan, so -
Tim Cook:
Oh. .
Dr. Jared Powell:
Made the best, made the best team win. Made the best team win. I'm sure you've got a chance. Okay. All right.
Tim Cook:
We'll leave it at that.
Dr. Jared Powell:
, Good. So can we talk about this paper? So how did it come to be, Tim? How did it come to be that you, as a fit, active, strong man, by the look of you, don't wanna give you too many compliments, is questioning strength testing in clinical practice, and we'll, we'll sort of anchor it to rotator cuff-related shoulder pain. Got it. Was there a moment that made you sort of second guess it, or has you been thinking about it for some time? Yeah.
Tim Cook:
Been on my mind for a while, just because in busy clinical environment, you've got a certain amount of time to try and fit a lot of stuff in, , in terms of your assessment and treatment. And I was just finding that I wasn't, other than very brief manual muscle testing, I wasn't really, and I'm, I'm still not really incorporating anything more accurate, possibly, if that's the right word, or, or, or I wasn't wasting any more time. Wasting's probably the wrong word. I wasn't spending any more time trying to, trying to more accurately quantify with other bits of equipment. So hand hei - handheld dynamometry, , for, for example. And I, I knew that this was a little bit at odds with the clinical practice guides or some of the clinical practice guidelines that were strongly suggesting for rotator cuff related shoulder pain to be, , attempting to quantify strength, particularly in abduction and external rotation, which mirrors the, the little woods, , which we reference in the paper, 2019 consensus, where a bunch of physios came together.
Tim Cook:
When, when you assess cuff related pain, subacromial pain, whatever you wanna call it, we all recommend that you should be measuring strength and probably abduction and external rotation. It kinda makes sense because when we think about rotator cuff related shoulder pain, like other tendon-related problems, one of its key facets is pain reproduction is very mechanical in nature, often with the, the painful art being part of that diagnostic criteria. So the theory is, you know, you load these sensitive muscle tendons and, and it hurts. So therefore, when we test those things in, in a clinical environment, we would expect supraspinatus, infraspinatus, you know, the two sort of big external rotation abduction contributing rotator cuff muscles. We would expect those to contribute towards no susception of the shoulder. So it fits this really nice, accurate, clean narrative. But I, I really just wanted to question that because I wasn't finding a great deal of value.
Tim Cook:
And I was thinking, is it me? Am I not being thorough enough? Am I under assessing? The other thing really coincided with that was as I started to teach this to students and, and putting pressure under myself to try and stay contemporary and up to date, I'm thinking, well, if the practice guidelines are telling us we should be, , performing this sort of assessment with, with cuff pain, I should be telling my students that this is, this should form part of, , an assessment. , Like I had been taught for, say, tennis elbow, lateral epicondalgia to test pain-free grip strength with a dynamometer, you know, then you go and do your treatment and then you test it and say, "Oh, look, the, the number's gone up. Great. We can tell that your problem's improving." The last thing that was a real spark, so less of an insidious sort of thought process, but more of a spark, was, was listening actually to Eric Mada.
Tim Cook:
So I know you've had him on, on your podcast. So going back a few years now, so his PT Inquest, , podcast, I always found fascinating, and I'd often listen to it on the way to work. One particular podcast, he was describing how he was using handheld dynamometry and isokinetic dynamometry. And I know his special interest is in knees. And he was describing how he would often use it as an assessment as part of a, , a clinical consultation in a, in such a way that, say, for instance, for someone with patellofemoral pain, he would ask that patient to, to load the quadriceps, so he'd ask them to isometrically contract, you know, their knee into, into extension to the point where they felt pain and how that was somehow a really accurate quantification of th- their problem. You know, it's the point in which their body is perceiving load as threats.
Tim Cook:
And it just struck me that is, that's a, such a lovely simplification of this problem. I wonder whether it's the same for the shoulder, and I wonder whether it's the same for rotator cuff related shoulder pain. And then that sparked the, this, the idea of my PhD, and therefore kind of creating studies of which this paper forms kind of the initial chapter, if you like, the introduction as an editorial, setting the scene, , around this sort of strength assessment, but also strength as, as a treatment. And I know a lot of your work, , has been into this, Jared, as well, so it's obviously read, read lots of your, your papers. And so, you know, it was kind of that, that mixture, really, and it really just struck me. And I, and Eric was really kind enough to give me some of his time. We chatted through, you know, his thoughts behind that, , and I really respected him for that.
Tim Cook:
And, you know, we talked through what, what, for instance, , an RCT would look like to test that theory. , And, and we've subsequently run that RCT, and, and I've recently written it up, and it's, it's gonna form sort of a second chapter, if you like, and it's, it's in press at the moment, so I can't really talk about the results, but that's the backstory, I suppose.
Dr. Jared Powell:
Cool. Love it. Love that you brought up Eric as well. Such a, such an articulate voice, and he was, he's the original - Mm. Physio podcaster. So the prevailing view has been, since I've been in practice 15 years, I'm gonna say 20. I reckon around the turn of the century in the 2000s when loading became in vogue for tendinopathy - Yes. That we've developed this fixation on strength. And it's, I think it's been wholly a positive shift away from, you know, perhaps more passive and, you know, fearing loading paradigm that, that tended to govern rehabilitation.
Dr. Jared Powell:
So we've gone through this strengthening paradigm, which I think, as I said, has been good. It's sort of hijacked a lot of our clinical practice where it's become find a weakness, intervene, fix that weakness, and then very predictably also, , with certainty, there's going to be a positive outcome. And we know that, like, when we, when I say it so crudely like that, it sounds a bit ridiculous, but that's genuinely what happens in clinics all around the world on a day-to-day basis. So is this just another oversimplification that we've been seduced by, much like posture, much like core stability? Is strengthening just another example of this or measuring strength just another, another example of this?
Tim Cook:
I think so. Yeah, I, I do agree. I mean, if you look at, so the sort of the shoulder classification framework, you know, and we've probably all heard this, and I think it's a very useful framework, and I absolutely use it when I'm teaching students, because I think, I think that rightly or wrongly, the shoulder can be challenging clinically. So the attempts to try and make it less challenging by having these sort of three or four broad buckets of, is it a stiff and painful shoulder? Is it an un- unstable and painful shoulder? Is it a weak and painful shoulder or is it something else? You know, that really helps as clinicians and teachers to sort of put these broad categories out there and these broad buckets. And those buckets capture most of the things that go wrong with shoulders. So obviously, rotator cuff related shoulder pain comes under this weak and painful shoulder.
Tim Cook:
Problem with that is you're, you'resaying, well, it's weak then. It's, you know, weakness is inherent with these presentations. And what we know is that the level of someone's strength or weakness or lack of strength, I suppose, doesn't tend to correlate particularly, , well with their level of pain and disability. But also that, yes, exercise, whether that be resistance training of all the different types or other types of exercise seems to help, but that you don't need to have significant improvements in muscle strength, however you choose to test that to see improvements in clinical outcomes. So it doesn't, it's not really matching up. So I've started to describe the weak and painful, , shoulder now as the, the flexible but painful shoulder. And I know that's probably, again, b - a bit simplified, but what I'm saying there is that in most people with rotator cuff related shoulder pain, this sort of umbrella term, they have this passive range that looks pretty normal, whether or not it's painful or not.
Tim Cook:
So they haven't got a frozen shoulder. , They haven't got glenohumeral joint osteoarthritis, and it's not an unstable shoulder for whatever reason, but it's not inherently weak.
Dr. Jared Powell:
Good. Love it. So I think this takes us nicely to the next point. What are we measuring when we measure somebody's strength or force output, especially in, in somebody with a painful shoulder? Are we measuring their pain or are we measuring their absolute force production or, or force output? Because we need to know, right? Because what comes first? Does a defi - does a lack of strength come first which causes pain? Or does pain come first and cause a reduction in strength? And this matters because when we're talking about, when we're making causal claims, which is what we're doing here, we need to consider temporality, which is what comes first. And if we're treating strength, a lack of strength as coming first and it's incorrect, we're not doing the right thing. So, so this is not just the philosophical point, this is a really pragmatic point.
Dr. Jared Powell:
So I guess my question is, what are we measuring when we measure somebody who has pain trying to measure their strength? Are we measuring their pain tolerance or are we measuring their strength or a combination of both?
Tim Cook:
I think we're measuring, you know, so Eric, going back to Eric, he, he talked about this a lot, , in the podcast, is you're not, in the presence of pain, you're not really testing someone's strength, you're, you're testing someone's pain tolerance. And obviously we're gonna know that that's gonna be completely different because of so many different reasons for different people. I think obviously in writing our editorial, I had a look around to see whether there were any prospective studies that measured people's, people without pain, people without diagnosed rotator related shoulder pain, measured their strength, and then followed them up to see whether they would develop it. So whether it was a risk factor. With an editorial, you're obviously given free license to a degree, and it's much, it's very much a narrative process. So it's, it hasn't got the rigor, I suppose, of something more systematic, like a scoping or a systematic review.
Tim Cook:
However, having written a systematic review, currently writing a scoping review, you know, I'm, I, I'm fairly proficient at looking across the evidence base. And I, and I think I found one study on, I think it was either swimmers or handle, professional handball players, some, it was something quite a niche little, little cohort that, that said that I think it was either the internal external rotation strength ratio was a predictor of. But, but nothing else in sort of general population, not obviously, but that's the type of patient I'm gonna be seeing day to day. So my thought is that, you know, chicken and egg, I think people develop rotator cuff related shoulder pain. And as a result of that, often we test their strength and it's, and it's weak because it hurts. You know, back in 1994, I think, Ben Yeshe, local anesthetic, promo injection paper, measured pre and post-injection strength, and the changes in strength when they took pa- patient's pain away was, was really significant.
Tim Cook:
And it's, again, for readers, go and have a look at, go and have a look at that, that paper in, in the, the article. So that's my bias. That's. I, I think that the, , relative weakness is, , is an individual experience that's gonna be there for different for everybody. And, and is this a symptom of the fact that they're perceiving pain with these, with these various movements? And that, and, and if you think about the clinical assessment, you know, and going back to that Littlewood paper, resisting abduction and external rotation is obviously, is often pain-provoking. So they're almost. I, I find of, you know, I often test strength in my assessment knowing that this is probably gonna be pain provoking. And it's almost another little test within that cluster. Have they got a painful art? Yes. Have they got full passive range of motion?
Tim Cook:
Yes. Have they got pain on abduction, external rotation? I've got quite a lot of evidence there that it's, it's pointing towards this, this rotator cuff related shoul - you know, subacromial shoulder pain diagnosis here, because I can rule a lot of other stuff out. Not to say it has to be painful, is the other thing, because sometimes with manual muscle testing for abduction, external rotation, it's not, it's not always uncomfortable. And this is anecdote, but l - a lot of the time it is. Sometimes it will be another movement, or sometimes it won't, it won't necessarily be a movement that provokes their symptoms. And that's probably, if we go into a totally different field, when we talk about special tests of the shoulder and we know we, you know, the, the history of, of that area, that's often where I'm then relying on a Hawkins and Kennedy or a near sign or, or something similar, lateral jobs test, something that it w - that is really provocative, I think, in my mind, to the structures around that space.
Tim Cook:
That's sometimes when I fall back on those tests to, to, to rule something in or out. And if it's, if none of those things are provocative, then I'm thinking, and maybe it's not the sh - maybe it's not the cuff. I'm, I'm what, what about you, Jared? What, you know -
Dr. Jared Powell:
For me, I just wanna, I wanna bring up that point that you mentioned with the anesthetic injections. That's almost a nail in the coffin for me where, you know, to increase someone's strength instantly with anesthetic injection without doing a strength program means that the pain is limiting that person's force output and not in the other direction. So that's irrefutable evidence for me, and I think we can do that in many circumstances that we're probably chasing a symptom, which is a lack of strength, as opposed to a cause of somebody's painful experience. And I think that's okay. Like, you and I wanna make it very clear that we are proponents of strength testing, if you want, and also resistance training, right? Like, let's avoid any straw man interpretations of our argument. You can do it, but I think we're just asking people to think in a more sophisticated manner.
Dr. Jared Powell:
Would, would you agree with
Tim Cook:
That? Definitely agree with that. And I know, I know I'm sort of moving on a little bit, but I think where this leads to then is then the whole argument of using exercise as a treatment for this problem. And I think Greg Lehman talks about this a lot, of working out. Sometimes the most challenging thing in physio is working out, is this a problem I can nudge into? In, in which case, allow the patient to work in and around pain? Or is this something we should kind of purposely avoid not provoking? And that, I think, is always fascinating. So are we strengthening everything up around the shoulder? Strengthening, again, I'm using this word. , You know, so are we, are we getting them to exercise muscles around the shoulder whilst the structures that are sensitive are settling themselves down, you know, and the two coincide together?
Tim Cook:
You, you settle it down, build it back up, that kind of ethos. Or are we asking patients to challenge the shoulder in a way that, that may provoke symptoms, like with, you know, Achilles tendinopathy, patella ten- tendinopathy, and this sort of contemporary approach of saying, look, it's safe to do that. And we know that, you know, the studies support that. It's totally safe to do that. And that in some way, whether it be physical, you know, changes within the tendon and, and mechanical properties of low tolerance within the tendon, or whether it's much more of a top-down process and of some sort of mechanism that, that down-regulates the experience of pain through exercising in a little bit of pain. I, I think that whole question, each time you see a patient is something that we should be asking ourselves. And I often find myself asking.
Tim Cook:
And sometimes it's really challenging. You have this open conversation with patients about how you manage this. And you'll say, "Well, look, you know, we know it's safe to exercise into pain. You don't have to exercise into pain. Why don't you try this and see if it works? And if not, we'll try a different, , try a different tack." And I, and I know that Greg Lehman also talks about this kind of avoider versus endurer, , these two buckets. So is this a patient who is fear avoidant and actually they might need to nudge into experiencing that it's safe to exercise in and around pain because they've been so avoidant? Or is this someone who's just enduring pain, no pain, no gain, you know, and it's just not getting better because they're constantly stirring the thing up? And actually, they're the people we need to bring back a little bit and say, "Look, I don't really want you pushing into much pain when you exercise.
Tim Cook:
And I think you might just be poking it too much." That's I find fascinating. And that obviously all of that fits into this assessment part of the question.Because then obviously the assessment often in physio guides in how we treat.
Dr. Jared Powell:
Yeah. Well, let's talk about that. So what value is strength testing giving us in terms of guiding treatment choices if indeed strength does not mediate pain outcomes or function outcomes in people with rotator cuff related shoulder pain? So if somebody comes in - Yeah. You test their external rotation, they are weak by whatever standard you're comparing it to, maybe the other side, or maybe some normalized data that you have, you then say, "Okay, let's improve this by doing external rotation exercises." And then they get better. So, like, because we now have some data that strength doesn't seem to mediate outcomes across all sorts of musculoskeletal conditions, including the shoulder. If strength is not a mechanism of an outcome, then why are we measuring it in the first place? So, you know, to play devil's advocate or to, to suggest a position, you know, it could just sort of nudge us into, to use your word, into a nice and easy, coherent treatment pathway where this person is weak and painful in that position.
Dr. Jared Powell:
It's coherent that we might want to target that and it might lead to a, to a decent outcome. And I think that's plausible and logical, but - Yeah. Let's sort of suggest the opposite position. If strength is irrelevant to outcomes, as far as we know from the data that we have, then why are we testing it at all?
Tim Cook:
Mm. So yeah, it's very difficult to support, , I find anyway. This may be my own bias. I agree with that argument of, should we be doing this at all if it's not something that we're looking to necessarily have to change? But then, you know, the complexity, the complexity of the human experience of a, of a painful musculoskeletal condition sort of informs me that it may be really important for, for some people. You know, so it's. And we sort of say this, I think, succinctly at the end of the paper that, you know, it's, it's not throw the baby out with bath water. This may be a useful tool for some people. So if you have a person who, you know, is, is really interested in numbers, really wants to know their force output in a particular movement, or if that particular movement is very important to something they're really interested in getting back to, fill that sort of gap, whatever that may be.
Tim Cook:
I would use it, and I would support it, and I would say to them, "Yeah, we can absolutely see if we can change this number, change this outcome." But I would be really cautious as to say, "This number needs to change for your symptoms to improve." And I would just make sure that they're, they're on board with that. I would be cautious to sell it, you know, "This number goes up on the dynamometer, you get better. That's as simple as it is." You know, unle- unless it does, unless it does correlate with some people and they say, "Well, actually, , I'm finding I'm getting stronger at this, and also I'm getting better, and I think it's because I'm getting stronger." Fantastic. And it may well be, but I think you just have to be cautious not to go too far down that rabbit hole with that patient because it's, you know, can, it can be difficult to get back, you know, and it can be quite detrimental, I think, to therapeutic alliance and trust and rapport if you've sold them the narrative of, okay, you've got rotator cuff related shoulder pain because you've probably got some tendinopathy in the supraspinatus, infraspinatus, here they are, show them on the, on the picture.
Tim Cook:
Now, we load these things up, they get better at tolerating load, means you can do more with your shoulder. This is how we load them up with resistance training. We need, so we need you to get stronger on this, otherwise we're not gonna get you better. I think that is a narrative that I've probably used before, and I know that is, has been taught and passed down. And if it works, great. Fantastic. But I think there's a lot of parallels with that really simplified approach with, say, you know, the transversus abdominis and the low back pain stuff, you know, sort of late, late '90s, early '90s of, , leaping from one finding in a paper to then, okay, everyone with chronic low back pain has got weak transverses abdominis, or they're not switching on quick enough, and, and the multifidus is atrophied, you know? And I think we can, we've probably s - been guilty of going, possibly going down that route.
Tim Cook:
And it's, but it's been, but it's been an easy route to go down because all of this sort of early 2000 work on tendons, parti- particularly achilles and patella that, like, loading into how we get these better. You know, Alfredson's work with the heavy eccentric. Yeah, that's gotta work with the shoulder because the cuff is a tendon. So we do the same things we do with Achilles, it's gonna work. And it probably did for some people, it probably has for some people, but the evidence that we, we've looked at definitely questions that whole rationale.
Dr. Jared Powell:
Yeah. A- allow me to build a case for why strength testing could be helpful in rehabilitation, just to avoid, , any certain sections of the social media hysteria brigade going into overdrive. So in the paper, we write, "Strength testing may enhance patient motivation and engagement." And I think we see that. We, we can agree with that. It can be standardized, and it's objective. It's trackable. It's portable. I think portable is interesting because we can pack it up neatly into a number, and we can give it to another therapist if we're away for a couple of weeks, and that patient's coming back, and that therapist can then interpret that number and say, "This is the trajectory of this person's recovery." So - uh-huh. Yeah. Objective, trackable, and portable is helpful. So we're not arguing with that. It offers tangible metrics for communication with patients and referrals. We kind of just mentioned that then.
Dr. Jared Powell:
And it aligns with general health promotion messaging. Us as musculoskeletal clinicians are there to get people healthier, not just out of pain, I think. And encouraging resistance exercise is a good thing, and measuring strength is probably a gateway into that. So I just wanna allow you to, to sort of continue on and make a case for why strength testing can be helpful in some circumstances.
Tim Cook:
Yeah, absolutely. And, and even from its most basic tenants, you know, getting a patient to load their shoulder in what might be a provocative way in a safe environment under the guidance of you as a physiotherapist, for some people, may be very powerful. Look, look, we're loading this, this thing, and you're experiencing this, and I'm saying it's a safe thing for us to do, and this kind of makes sense of, of your problem. So in terms of, in terms of that, I think it's, can be really useful. Again, people like numbers, you know, these dynamometers are digital, so you'll get a readout. You know, that can, that can help, , with some - It's very
Dr. Jared Powell:
Theatrical. It's very analytical. It looks like you're ascentists.
Tim Cook:
, It takes time. Yeah. Yeah. It, again, it's something that other members of the team can use, like you say, and, and it's something you can track. I, I'm just cautious that, you know, what if the number comes down, people get weaker, but they start to get better. Yeah. Yeah. And then, you know, and vice versa, they get stronger on the machine, but their symptoms haven't really changed. I think sometimes that can be powerful because you can say to someone, look, although, and this is how it's sold often, your strength is improving, but your symptoms are still the same. But, but that's positive because we can say, look, you are able to put more load through this area without it being. It's still as uncomfortable as it was, but you're able to load it more. And, and hopefully, you know, what you're hoping is that in time, whether or not it's because of the strength improvement, but in time, the, the pain will catch up and the pain will, you know, fade off.
Tim Cook:
, Because it's hard to get around this perception of pain problem. You know, we, you know, we're all trained to ask patients what they're hoping to get from their consultation, you know, initial consultation. What are you hoping for us to get from today? The vast majority say, I want my pain to go. Yes, they're wanting to get back to whatever their, their goal is. But the, the main thing I find often is I just want the pain to go. That is a complex beast with some people, as we all know, which makes it fascinating. Yeah.
Dr. Jared Powell:
The, the first scenario that you mentioned where you're describing when you might measure strength and it's about, you know, being in a trusting and safe environment and exposing a person to load and, you know, getting them to interrogate how that feels and, and, and scrutinize what it may mean to them. That's important and that's why I think, , strength testing can be helpful as well. But it's not really strength testing, is it? Because you don't really care about the number. You care about the whole act of exposing this person to resistance. And then what follows from that is hopefully that person perhaps maybe being reassured or empowered or feeling better somehow in what they can and can't do, feeling more robust. It's not really the number that you're caring about. Right. It's the process, isn't it? Yeah,
Tim Cook:
They're engaged with that process. And, you know, you'd have heard of this, the theory of expectation violation. So prior to coming into this appointment, you know, they, they may be very fearful o- of, of moving and using their shoulder. You take them through a process of assessment of, and, and, and, and you, it's almost an expectation that this is gonna hurt. Perhaps it doesn't. Or perhaps they, you know, they score much higher on the dynamometry score than they were expecting to, you know, compared to their unaffected side. And it's a huge sort of disconnect from that sort of process, that associative process of, "I load my arm and it hurts." Also, I think with the, I'm not sure if you reference in the paper, Rachel's ches - Rachel Chester's work, prognostic indicators with her perspective stuff. Fantastic set of papers from probably 10 years ago and recommend anyone to have a read of Rachel Chester's work.
Tim Cook:
But the two really big things from memory, and I might, you know, apologies to, to her if I'm misquoting, but pain self-efficacy is a huge predictor, and as well as kinesophobia. So fear of movement, self-efficacy seems to be this recurring theme of someone's confidence in their ability to use their painful arm despite their pain. So it, you know, and delve into the self-efficacy literature, they often talk about mastery through repetition. So, you know, being taken through a strength testing process could sit, could be witnessed, could be viewed under the lens of them mastering moving their arm again, you know? And then we give them exercises, even though it's uncomfortable at times. And we, we normalize that and make it safe. We try and downregulate fear, kinesophobia. We try and improve their confidence in their abilities. Perhaps that's one of the ways that exercise might mediate recovery in.
Tim Cook:
These people. It's kind of. But again, like with all of this, it, we've got to be. And I know that, you know, your, your scoping review, it, you know, one of the main findings was that with a lot of this mechanistic work hasn't been done. You know, these, these mediation analysis hasn't been done. So we have to be really careful to make those conclusions, but perhaps that's. , Because you can, you can often find during the assessment, patients suddenly perform better after the assessment. So, but perhaps there's something in the assessment that's part of the treatment process. Peter O'Sullivan talks about this, you know, with manual therapy and how, you know, the old school mainland mobilizations, et cetera, may have come, come and gone in terms of fashion. The act of putting hands on somebody as part of an assessment is very powerful, you know, and I reflect back on.
Tim Cook:
So there might be parallels there. I reflect, reflect back on patients that have, have felt like they haven't been properly assessed because the therapist, whether it be me or one of my colleagues, hadn't actually put hands on them. God, that's really valuable to that patient. So perhaps having this assessment, this really thorough assessment, whether that be with dynamometry or not, is similar, has a similar sort of powerful effect on this, this person's really looked after me, they've really assessed me properly. Have they even used this digital dynamometer? Wow, you know, they've given me a readout, give me a number. Maybe there's a study in there somewhere, you know, compare digital dynamometry with manual muscle testing and see whether the people who had the digital dynamometry had better outcomes, whether or not it changed the strength.
Dr. Jared Powell:
There's a PhD in that for somebody. I'm
Tim Cook:
Not gonna do
Dr. Jared Powell:
That one. I think Adrian Lowe wrote a paper about, , 10 years ago, which speaks exactly to this point. And the title of the paper, I believe was Assessment is Treatment. Okay, yeah, fine. And, and this, it also takes me back to the paper that, , Jeremy and I and Natalia Costa and all my PhD supervisors wrote a few years ago called Restoring That Faith in My Shoulder where it was a - Yeah. A qualitative study. And patients are describing exactly as you have suggested that during an assessment where the physiotherapist was encouraging a patient to do a painful movement, that she was in complete shock that she could do it. She all of a sudden felt - Okay. Completely pain-free and confident just by doing 10 sets of lateral raises that she though she couldn't do anymore. So there's nothing changing in that physiologically. She just, she's just now violated her expectation and she's now feeling better about herself.
Dr. Jared Powell:
So there's so much within that, and I think it's such a, a powerful thing. I wanna start to, to get to the end of this. I'm conscious of your time here, Tim. I, you've written in the paper a, a really nice sentence. Y- you, you wrote. I can't remember who wrote it. We wrote it. You've written that, "Patients don't come to get stronger. They come to feel better." So do you think that physios and, you know, we can talk about all musculoskeletal rehab providers here. Do you think sometimes we mistake a means for an end? And sort of here I'm, I'm setting you up to maybe talk about good heart's law a little bit. And, and maybe why do we get so focused on these proxy surrogate measures rather than just focusing on the thing itself?
Tim Cook:
I think, yeah, I think we simplify things don't. We like to simplify things. Yeah, you know, you, this, this approach of treat what you find. Well, we've assessed you, we found this as weak, therefore that's where the treatment goes. You know, it's nice and simple. Is it Godhart? The Godheart law, , thing was interesting. Actually, that was, that was your inclusion, Jared. So thanks for that. You know, and apologies if I, if I haven't sort of translated this well enough, but when the test becomes the goal, you've got a problem. So when we're using strength testing, and then we're just trying to get someone better at performing the test, that's where you can, you can have the problem. So we want, we may well want the test to improve, the outcome of the test to improve, but it might not be through just practicing the test that the test gets better.
Tim Cook:
And, and in actual fact, in other fields of life, following that approach, you know, doesn't, doesn't always help. I'm not sure if I was answer- answered your question there.
Dr. Jared Powell:
No, that's good. So I, I'll give an example. If you're obsessed with external rotation in neutral, you can gain that to get better over time - Yeah. To the specificity, right? Because there, there's a skill element to it as well. But how does that translate into playing tennis or lifting your children overhead or, or whatever it may be? There is a disconnect between that simple test and the life that person wants to lead. Do you have an example of that?
Tim Cook:
Absolutely, yeah. Yeah. No, I, I think that, yeah, you've summarized it much better than I have. And that's, that's where we sort of finished the paper. That's the link between people come in to feel better and they wanna get back to the things that are important and meaningful for them. It's not, it's not sort of a nail in the coffin approach of saying, well, don't just get them repeating the test. I mean, you may if, if, if there's, like we said, if there's an incident, , if it's an incident, if there's a, , a, a good reason for them to want to get better at te - at that particular movement for that particular person, great. But don't expect, like you say, of just isolating abduction and external rotation in particular, because they're the ones that keep coming up. Don't expect that to translate across, you know, all of the amazing movements and functions that the upper limb, , the upper limb have.
Tim Cook:
And we talk a little bit about the fact that lots of what we do with the shoulder requires endurance. So why are we testing a, a, a brief isometric maximum voluntary contraction for five seconds? You know, we're testing two very different things. And so it kind of makes sense intuitively. Yeah, why would we expect a, you know, a, a one rep max with my arm by my sides into external rotation to have any impact on repetitive task above my head? They're totally different, aren't they? Yeah, I think it's kind of the closing thoughs for us to kind of get clinicians to, to, to question that, , to think why, why we're, we're doing that. Whether there's a, a more individual type of movement-based assessment that might be more relevant for that patient. But again, don't make the test the treatment, if you like.
Dr. Jared Powell:
Yeah. And look, I think, and, and to, again, just to sort of, , ward off the naysayers and the critiques a little bit, if you're chasing a specific biomotor attribute such as strength in your rehabilitation for, you know, an ACL rehabilitated athlete or, you know, hamstring strain or a calf strain or whatever it may be, if you're an athlete and you need a certain amount of force output, then please measure strength objectively and track it over rehabilitation. I don't wanna say the average, Joe, but for the, for an everyday presentation of, you know, non-traumatic rotator cuff related shoulder pain or really any other non-traumatic musculoskeletal condition, what's the value in spending an inordinate amount of time measuring strength in an elaborate way when it may not need to change that much? What's your thoughts around that little spiel?
Tim Cook:
Yeah, abs- absolutely. So we're absolutely not saying it's, it's worthless. And there may be clinical examples. Like you say, you know, we always lean on sporting populations. So there may be clinical examples. So with the knee and, and post ACL rehab and the whole limb symmetry index and quads index, and the research is pretty, pretty tight on that, , in terms of the quad strength and, and gaining at least 90%, you know, symptomatic versus, , asymptomatic. And so intuitively think, okay, well, swimmers, baseball pitchers, cricketers, tennis players, people who ch - really challenge their shoulder in these sort of extremes of movement, you know, it would be very sensible to ch - be challenging their musculoskeletal system in these really challenging positions, and then testing the difference between their symptomatic and asymptomatic sides. And we're, we're absolutely saying that. And I, I think, I don't think that's, , you know, I don't think we're saying that it's worthless in those populations.
Tim Cook:
And, , and probably because of that, you probably see more support in the literature for, for testing in those populations. But again, there's a part of me that says, "Well, that just sounds like sensible rehab anyway." Is the testing of the strength in those positions really that necessary like it is in ACL, , rehab? And I'm not sure, and it may just be that a lot of my research is centered around more of a general population cohort. But, but for the sort of, the sporting population researchers who work with those upper limb athletes, , those, those athletes that use upper limbs in those challenging positions, there may be a, a bulk of evidence that's very supportive of, of using it similar to how we use it post - ACL.
Dr. Jared Powell:
Good. Okay, Tim, I think we've, I think we've got all we need to get. That's been solid. I also think we've, , managed to be diplomatic enough to, , hopefully not get any hit piece ticked in. I hope so,
Tim Cook:
Jared.
Dr. Jared Powell:
Good. Do you have any. So tell us what's next for you. Are you. When can we expect this paper come, to come out?
Tim Cook:
Yeah, it's, it's currently with the editors. , So this is the, , randomized controlled trial where we randomly assigned two groups of patients suffering with rotator cuff related shoulder pain to two different assessors. So effectively, two groups had a different order of assessor. So assessor one, sorry, assessor one, then assessor two. The other group had assessor two, then assessor one, so they sort of crossed over. And we looked at pain-free shoulder abduction, external rotation, and we compared relative deficits with symptomatic and asymptomatic shoulders. So they had to have unilateral rotator cuff related shoulder pain. And so what I was interested in, first of all, before we make any assumptions about how valuable that data was, we looked at the reliability of it. So that was, that was sort of aim one. And then secondary outcomes were then to try and correlate a quads index, but with the knee, to try and, , see whether we could correlate sort of a abduction index or a, a pain-free, , external rotation index.
Tim Cook:
And so a relative degree of weakness, if there, if there was, , relative to a pain-free weakness to shoulder pain and disability index to see, well, look, you know, and like, like Eric had said in that podcast, because you would expect that the larger the, the difference between strength, pain-free strength in shoulders would correlate with a, a worse outcome in shoulder pain disability. So the, the relatively weaker you are in inverted commas, the more pain disability you'll, you'll have. So that was something that we were really interested as a, as a secondary outcome. Now we need to understand from a methodological standpoint that because our primary outcome, a sample size and power calculation was geared towards our primary outcome, which was our reliability, reliability of the testing, both inter and intra, we understand that we've got to take those sort of secondary outcomes with a large pinch of salt because the, the study's not designed, , in that way.
Tim Cook:
, And then finally, we looked at, we also measured pain self-efficacy, kinesophobia, and the pain catastrophizing scale. So three of these, you know, big often s - , often cited, , questionnaires that, that, , , have been referenced by, again, Rachel Chester but others to see whether they had a closer correlation with the, the, the relative, , weakness. So that's kind of second, but that's all, they're all lumped into secondary outcomes. So, yeah, that's, that's in press currently. It's just keeping your fingers crossed. And then I'm moving on, and I'm currently sort of probably halfway through a very similar scoping review, , to, to yourself, Jared, but whereas you had included randomized controlled trials, I believe, in your review. , I've been given the task of opening that, the fat net wider. So we're looking at any paper that's used exercise for the treatment of rotator cuff related shoulder pain, and we've included other scoping reviews, other systematic reviews.
Tim Cook:
And what we're gonna look at is probably, , as you all know, , well, is trying to gain an understanding from probably introduction and discussion sections, what are the proposed mechanisms? So first of all, is there a mechanism that's mentioned at all as to why they've chosen exercise as a treatment? And that, and then, you know, what that mechanism, me- mechanisms is, and what the gaps are, you know? So that's gonna be sort of a, a big undertaking. I'm at the stage where I've finished. Personally, I finished my initial search and we're down to about 330 papers, which I'm not really sure if that's bigger or, or smaller than I though. , But that's been an, an interesting journey so far. And then my other reviewer, Luke, he's a colleague of mine, clinically, he's gonna do the same job. So we're both gonna draw out our data and then, and then compare what we find once we've finished our, our searches.
Tim Cook:
So that's where I'm at with that. And then, then it tees me up in some way to finish off probably with either a mixed methods study, trying to tie it all together. So, you know, this, this sort of initial introductory chapter, this editorial is kind of setting the scene of sort of questioning this, this area. Second trial is in se - looking at the assessment at point, particularly in, in strength assessment in an RCT setting. Third paper is much broader, and it's, it's diving into, you know, mechanisms of strength of the treatment and what we may or may not know. And then I'm thinking that we'll probably either try and extrapolate from that, that scoping review, some sort of what optimal might look like exercise program for a small case series, a small, small cohort of patients. Take them through that process of delivering it, and then probably include some, like you had done, some qualitative stuff at the end.
Tim Cook:
So, so no, so not only look at their outcomes, , and what might explain some of their outcomes from a sort of quantitative, , perspective, but then what their lived experience of that was. So that's kind of the final, the final sort of. Well, I think, I think which is the s - the final iteration. , And that's changed a bit. And anyone who's, anyone's, I'm sure you can testify to this, but anyone who starts a PhD or a big project like this, you're told at the start this, your ideas will probably change. So what I originally had submitted and got ethical clearance for a second trial that's slightly different to that one that w - I was, I was really interested in specificitive of exercise selection. So I was gonna, two groups of patients, and if someone else wants to do this, go for it. So one, one arm of, , exercise would be, , resistance training, you know, as, as one exercise science colleague suggested, you know, what optimal looks like, periodized and, and, you know, percentage of one RNs and all that kind of stuff.
Tim Cook:
So it was really sort of bells and whistles, resistance training for abduction and external rotation, comparing that to resistance training for abduction and, and extension. So, you know, in my head, I'm thinking, well, we're really trying to load that posterior cuff and those abductors in one arm, and we're trying to do the complete opposite in the other arm, and would there be a difference in outcome at the end? But yeah, for, for various different reasons, probably methodologically, pro - , probably partly funding and just the size of that project in order to be able to get enough patients and take them through, you know, a three-month program, 12 weeks, you know, because if I do it for four weeks, everyone's gonna say, "It's not long enough. You know, it's a strength training program. It needs to be at least 12 weeks. Possibly, yeah, longer than six or eight, definitely." , so it just, it became this monster in my head of like, okay, we're gonna have to bring this much smaller.
Tim Cook:
Maybe, maybe that's the postdoc. Maybe that's the postdoc study. Do you wanna do it? We could do it quickly. I
Dr. Jared Powell:
Like that, I like that you're thinking about postdoc already, Tim. You, you haven't been traumatized enough.
Tim Cook:
I haven't, I haven't told my wife that one. No, definitely not. Definitely not. It needs to be a few years. , It
Dr. Jared Powell:
Sounds, it sounds, it sounds like a really good PhD, mate. And yes, everybody who's done a PhD, it always ends up Frankenstein sort of version of what you thought it was gonna be, and it's this cobbled together thing. But sounds like you're on the right path. Well done.
Tim Cook:
Thanks. Thanks a lot. Yeah, congratulations on yours. Thanks, Frank. I listened to the podcast, , you did with your wife. It's fascinating.
Dr. Jared Powell:
Yeah, she had two. What
Tim Cook:
Was it like being interviewed by your wife? Oh,
Dr. Jared Powell:
It was just another day.
Tim Cook:
That
Dr. Jared Powell:
Was, no, it was good. It was good. Cathartic for both of us, I think, because it was a big journey. I
Tim Cook:
Bet it was. Yeah. - Draw a line under it,
Dr. Jared Powell:
Move on. Yeah, that's right. Yeah, we had a little champagne after as well, so it was really good. Oh, good
Tim Cook:
On you.
Dr. Jared Powell:
Yeah. C - where can people find you on the side? Are you on the socials, mate? You're not too active, but you're, you're on there?
Tim Cook:
I'm not hugely active. I'm on there. Yeah. , I think I'm under Tim Cook Physio. , So fairly simple on, on Instagram and, , on, , X, I believe. But, , yeah, I'm not, I'm not a huge poster. I used to use Twitter a lot, actually, because I used to really enjoy engaging with conversation. Mm-Hmm. I though it was a real asset for us. But it's, , maybe it's, maybe it's, , since it's, it's moved over to X, or maybe it's just my own personal interest in it. It's, it's sort of reduced slightly over the years, or just don't have enough time. I'm trying, I'm trying to limit my screen time, you know? Yeah. 'Cause I spend so much time behind computers, so trying to set a good example for the kids. Good.
Dr. Jared Powell:
Yeah, good for you.
Tim Cook:
Not be on my phone all the time.
Dr. Jared Powell:
Good. , Okay. Tim, thank you very much.
Tim Cook:
Thanks a lot, Jared. Thanks for your time.
Speaker 3:
The Shoulder Physio Podcast would like to acknowledge that this episode was recorded from the lands of the Tirabalang people. I also acknowledge the traditional custodians of the lands on which each of you are living, learning, and working from every day. I pay my respects to elders past, present, and emerging, and celebrate the diversity of Aboriginal and Torres Strait Islander peoples and their ongoing cultures and connections to the lands and waters of Australia. I
