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David: Hi Ebonie, how are you?

Ebonie: How are you?

David: Yeah, good, good. Thanks for coming on the podcast. I've been wanting to chat to you for a long time, all about tendons and get your input and experience, so I'm really looking forward to our chat today.

Ebonie: I'm excited. Thanks for having me.

How isometrics emerged as a tendinopathy treatment

David: You've got a fair interest in tendons. Where did your interest in tendons and actually isometrics, where did that all come from and how did it come about?

Ebonie: Interestingly, so I actually did my honors project with Jill Cook in 2002 when I was an undergrad physio, but it actually wasn't on tendons and I probably didn't really even have an appreciation of how much she'd done in that space as an undergrad. Which is crazy because she was at the uni that I was studying at. Then I was lucky enough to go up to the Australian Institute of Sport as the post grad scholar in 2007. And Craig Purdam, another tendon giant was the head of the department. And so we do little tutes on tendons, but interestingly, I think my clinical kind of passion came from looking after basketball. So when you're up at the AIS, you work with a lot of different athletes, but there are some sports that you are assigned to a bit more often and I worked with basketball, so I saw quite a few tendinopathies. And I think David, the interesting thing for me was if someone had bone stress or if someone had a muscle strain, we could give quite a lot of clarity to the coaches and the athletes on the timeframe and the restrictions and the tendinopathy, particularly in season, despite how much had been done,

it was a little bit of, "Oh, I think we can keep going Or there wasn't much we couldn't be as definitive. And so I think they were the ones that I found the most interesting to manage and work out how we can manipulate load, but keep them going. And so it was a lot of sort of trial and error and clinical trial and error that kind of borne out some of the early research projects.

David: And then how did that evolved into isometrics? Where did that come from?

Again, clinically Jill and Craig actually saw a football player that had patellar tendon pain. And they tried unloading and all of those things. And what they actually tried was heavy isometrics. And that's on the back of that first principles and that clinical reasoning.

So if we think about a tendon, our tendons in the lower limb particularly act as springs. And so what they're designed to do, but also what is a challenging load for them is when we are asking them to act like a spring really fast. And so the converse of that is that anything slow or anything static should be really safe for a tendon.

And so that's what they tried clinically. They tried playing around with an isometric and the athlete reported, that they felt a bit better, that's an N=1 and it could be placebo and all of those things. So what we decided to do was test that in a research capacity, my original kind of little pilot in the lab, I thought, we're just warming them up. So all the isometric is doing is just load. What we have to do is match for time under tension and match for RPE because otherwise how do we know that it's isometrics per se. It could just be get them to do through range.

And so interestingly, with that early study, I also did it as a crossover. So again, it's not just how that athlete responds, how does that athlete respond to either load? And what we found is that the isotonic and isometric both help, they're both not provocative, but that immediate impact of isometric was greater in terms of analgesia. And it also was associated with the change in cortical inhibition. So that sort of led to the next project in and around more the brain side of things.

David: Yeah, they're both loading the tendon. They're both helping to impact what's the tendon's capable of. But then you're also getting the pain inhibition effect with the isometric. Is that right?

Ebonie: Yeah. that's right. Over a longer period of time, the isotonic also impacts inhibition. So I think that they can be both used as tools, particularly in season. I think in season we really struggle to work out what load we can add because our athletes are already really highly loaded. But you want to think about high load in terms of that spring and be really comfortable that isometrics and isotonics are really safe to add in season, either on the same day as a training session or a game or in that gym setting. So if we take away those slow and static loads, what we actually see is this sort of progressive decline because we just get more and more kind of loss of capacity over a season.

How loading helps a tendon

David: Yeah And so the isometrics or any of that loading that you might be doing, helping to maintain that load capacity throughout the season, because it sounds like the running or whatever it is, isn't achieving that same amount of increase or helping the tendon to be able to cope with with the load, is that right?

Ebonie: Correct. What that will do is it will load the tendon very quickly. It's very high load, but what it doesn't do because of the rate of loading, is it doesn't load our muscle. And so if we don't have the strength work in there. What we have is this decline in the muscle capacity. And if you don't have a really good, strong muscle, the tendon really struggles to do its job.

So you need an amazing muscle for the tendon to be able to pull on.

Tendon structure & how to describe tendinopathy to patients

David: Yeah. Great. And

I want to maybe talk about the structure of the tendon to give people a bit of an intro and information on what a tendon looks like in a healthy tendon, maybe an unhealthy tendon. So can you give us a little bit of an idea about what it looks like? Start with an healthy one and then move on from there.

Ebonie: So a normal tendon that doesn't have any changes, what you have is very few tendon cells called tenocytes. So there's not very many of them, but they're very communicative. So they talk to each other along rows and between rows and they really respond to the environment.

So the loading environment and the biochemistry, that's in the environment. And so what we have is small proteoglycans or small proteins that's called decorin, and they don't bind very much water. So there's not a lot of water in normal tendons. We have really strong type 1 collagen, and you actually don't tear normal collagen. So if you pull on a bone tendon muscle, what goes first is the muscle tendon unit. So that's a muscle strain. Then we have the bone tendon junction. The last thing to go is actually the tendon in a normal tendon. So that's Hazel Screen's amazing work.

When we have rupture, we know we've had underlying pathology. In our normal tendon, we've got this lovely, mainly type one collagen. We also have this ground substance, which you can think of the mortar and you can think of the type one collagen as the bricks. So we've got our bricks and mortar, very strong structure.

It's actually incredibly complex, the makeup of it. So I've simplified it a lot. And what we can have is we can have this pathological change and this can occur with or without pain. So we have no idea what the nociceptive driver is in tendinopathy. So the process that I'm about to describe can happen completely asymptomatically and does.

If we get an overload of the tendon, the first change is actually the tendon cells. So we have an increase in the number of the cells and we have a change in their shape. So in a normal tendon, David, they're quite sort of spindle shaped. But what happens with internal compression and internal shearing with overload is the tendon cell becomes more like a chondrocyte because of the compression.

What they'll also do is they become very selfish.

This is how I explain it to the students, and a selfish cell only cares about itself. So what it does is it plumps these big proteoglycans around itself like bubble wrap, and these proteoglycans are called aggrecan, and they're big and big proteoglycans bind a lot of water. So why do we care about that?

That's the swelling that you'll see on imaging. So that swelling on imaging is not inflammation. We know that it's bound water. What can start to happen is you can start to then change the function of the cells, and the cells will start to produce more sort of type three collagen, which is not as strong. So then this water can cleave apart parts of the collagen. And the final kind of pathological stage is an ingrowth of neo vessels. And again, we know that these neo vessels are not associated with like afferent or pain or sensation. They're associated with vessel diameter. So you can have a tendon, that lights up like a Christmas tree on Doppler. They've got lots of neo vessels and they can be completely asymptomatic. The relevance of the vessels probably relates to how far along that process you are. So once you have neo vessels, you probably have an amount of irreversible pathology. Sean Docking's fantastic work in the Achilles and the patellar tendon showed that most people actually have this adaptive process where you have changes in the tendon, but you also have a thicker overall tendon. So people will see that on the imaging report as an increase in AP diameter. I want you to take that and speak to your patient or your athlete and reassure them. That's fantastic. You've got this great adapted increase in tendon and increase in AP diameter is positive. what we want to do is get the loading right for the tendon, get your muscle really strong, do some really cool things for the brain, and you're going to do really well. There you go pathology 101.

David: And that's a really nice message to give to patients if they're worried that their tendon's all thick and or they've got this pathology that's been seen on imaging and they're saying, well, what's going to happen with this, but you're giving those positive messages about it.

Ebonie: Absolutely. And it's a positive message based on science.

Not just saying, don't worry about your imaging. If someone's had imaging, you have to unpack that. You can't just tell them to discard it. They're going to Google everything that's on the report. So actually use the science to reassure them. Don't let people use terms like tendonitis. Explain to them. We used to think it's inflammatory.

We now know that the process is actually pretty complex. But what you see on imaging, that's actually water. Because if people think it's inflamed, you could write the world's best exercise program. They're not going to do it. because it's a mismatch between what they think they need to do and what you are giving them because they think there's this underlying inflammatory component. So don't let them get away with using the term tendonitis and think that it doesn't have an impact. It does, it has an impact.

When and why tendinopathy develops

David: And why do we get the areas within the tendon that do have these changes? Like we're, we're looking at sort of normal activities. You're running around, you're playing basketball, or you're going for a run or doing whatever you're doing. Why does the tendon start to develop these changes?

Ebonie: So if we're talking about the patellar tendon, we know that these changes actually occur as your patellar tendon is trying to form a mature attachment. So that's during puberty. So there's some wonderful work, that we've done supported by the NBA where we did serial scanning of athletes on, in a number of different sites over six months. And we looked at them in relation to their pubertal status. So you can actually calculate peak height velocity. That has helped us really understand why there can be a difference between patellar tendons, for example, and the prevalence in men and women. Okay, so women or girls hit puberty earlier. So they are often not in really high level programs, by the time they've hit puberty.

They might be hitting puberty at 10, 11, 12. And so they might be playing, recreational sport, but they're often not in really elite programs. And there are some exceptions, gymnastics being an obvious one. by the time they go into these really elite programs and they might be recruited into a basketball center of excellence, they've hit puberty. They have a mature tendon. When we think about our boys and our men, particularly our tall men or our tall boys that are late to puberty, that have that late growth spurt and they become our taller ones, they can be doing 11 sessions a week while they're going through the maturation at their tendon bone junction.

So they get a disruption of that tendon bone junction that's there for life, which means if I scan that person as a 40-year-old, it's been there for 25 years. It's actually not that relevant. The patellar tendon probably is associated with the load that you do during those adolescent years. The Achilles tendon is load over time, so regardless of when you might take up running Kevin Le Baill's work showed that if you've been running for more than seven years, you've probably got changes in your Achilles. And they're all asymptomatic people. So that's more a load adaptive change. It's more a load response much like a wrinkle on your skin. It looks different but it's still very functional.

David: Interesting. So you've got these changes in the tendon, in the patellar tendon from when puberty, from those activities there. So are you saying it's less likely to happen in girls because they're not performing those like high load activities or lots of training sessions per week as often or as frequently in girls until after the puberty. So do you see it less in those.

Ebonie: Correct. And the research would support that, that it's far more common in men. So what happens is you get a change in your tendon and that becomes a risk factor for developing patellar tendinopathy. So even the men and women that do have a change in their tendon, they won't necessarily get the clinical presentation of patellar tendinopathy.

It's just a risk factor. But if you have a completely normal tendon, you're protected.

Tendon imaging

David: And how do we go about assessing that tendon? What's the best way to actually identify if there are areas of disorganisation within the tendon and whether that's been there for a short time or a long time. What sort of imaging or other sort of ways can we check that out?

Ebonie: It's a little bit of loaded question a loaded question actually, because, you don't actually need to use imaging as part of your clinical diagnosis. So the ICON consensus work that we did imaging and palpation weren't part of the diagnostic kind of battery. And that's because imaging you can have a ton of asymptomatic pathology and palpation is actually quite sensitive. Lots of things hurt to poke, but not specific. I'm not saying we should use imaging as part of our clinical diagnosis. We just need to consider whether or not, if we are going for imaging, how relevant that imaging is. If you've got a 45-year-old woman that walks around the block, getting an ultrasound of her patellar tendon is completely irrelevant because, her knee pain is not patellar tendinopathy . She's not putting enough load through her patellar tendon for that to be the clinical presentation.

And so you'd be far more likely to, consider other imaging modalities. So if you want to look at just tendon, the gold standard would be ultrasound. But again, it's really putting your clinical hat on and questioning, why do you need it? What is this telling you?

David: Your research studies where you were looking at patellar tendinopathy or patellar tendon in girls or Achilles tendon across runners. If they've been running for more than seven years in those, they're likely to use ultrasound.

Ebonie: Spot on. So we used ultrasound, gray scale ultrasound for the Achilles to look at hypoechoic areas and thickness. And then for the one where we tracked people over the period of their adolescence, we used ultrasound tissue characterisation. So that was able to give us both AP diameter. So it gives you the features of gray scale, but it also can give you the different echo types.

So the echo types tell you how aligned the collagen is. So it can give you areas of disrupted, as well. So you can quantify the structural change a little bit more. So it's far more common to use UTC as a research tool than it is clinically.

David: To sum up that little bit, basically, if patients are coming in and they do have tendon pain, you're not often sending them off for imaging to help to differentiate or say you've got an Achilles tendinopathy or a patellar tendinopathy it's not normally needed. Your clinical tests are going to be more relevant.

For research, you're looking at ultrasound versions of ultrasound, maybe UTC or gray scale ultrasound to identify what's happening within the tendon.

Differential diagnosis - Achilles peritendinitis vs mid-portion tendinopathy

Ebonie: Because those are, they're asking a bit of a different research question than what you do clinically.

So clinically you're looking for the clinical diagnosis. Whereas in research we were looking at tendon like specifically structural change over time.

So your clinical diagnosis for someone that comes into the clinic. You really want to be satisfying "Do they have focal pain?" And I'm not talking about focal pain with palpation, I'm talking about focal pain under load.

It's quite a small pain location that's aggravated with high tendon load. Remember I said at the start, high tendon load is associated with rate of loading. It's speed. So are they using their tendon like a spring? We really want to see that the feature of that person's pain behavior is that it warms up, but it's worse the next day.

And that's really important, David, for differentiating in the Achilles, for example, between a tendinopathy and a peritendinitis. So if you have someone with Achilles tendinopathy, they have that, you know, mid portion pain doesn't move or spread associated with running. Warms up, but the next day they have that morning pain and stiffness.

That's a classic story. But if you have someone with a peritendinitis, that's an overload of the layers that slide and glide over a tendon. So that person might say to you, yes, it hurts when I cycle. So that's a lot of repetition, it hurts when I swim, it hurts when I'm on the rower. Or they might say it hurts when I run. I start off okay and then as I fatigue, they actually go through more range of motion and they overload the peritendon

So that pain behavior is a really useful question to help with differentiating those two because for your person with Achilles tendinopathy, you want to make sure you're getting those calf raises in. But for someone that has the peritendon, that is their provocative load. So the person that says to you, I was worse with the exercises you gave me either a sustained isometric or a heavy isotonic or a through range isotonic. That's a little antenna for you to be thinking, I've got to change my diagnosis and my management.

Does treatment change tendon structure?

David: For sure, and we'll come back to some management stuff later, but that's a really nice way of differentiating what's going on. You're looking for that response to loading and also the pattern over the next 24 hours as they perform an aggravating activity. What happens? So you started to load, and let's just say you're thinking they've got a mid portion Achilles tendinopathy and they, you're starting to load them up. Do we get any changes in the tendon itself, like we've got those areas, you mentioned there in the disorganisation or areas within the tendon? Can these areas fill in or regenerate or what happens with those?

Ebonie: They don't really change, the research would say. So people have looked at stuff over very long periods of time and from the perspective of the imaging modalities we have, they don't really look any different. Are there changes in the way it functions? Probably. I think we'll get better at discerning some of those changes, but that's why we really want people to be targeting improving pain and function rather than how it looks because how it looks may not change, which is why we don't recommend serial imaging.

So there's not great evidence that we can change the pathological area. But if you think back to what I said about the adaptation, it's probably not the outcome we're looking for. We're probably looking to just change pain and function and that might change over time. We, we might. have more information at a biological level, but the actual structure of tendon is so complex that we don't really make new normal tendon after puberty. So there was the carbon bomb study, so Katja Heinemeier looked at it, and the half-life of tendon, like the turnover is 200 years. It's not like muscle and eyeballs and yeah. The tendon, once you've laid down tendon, that's the tendon that you have. So it's a very complex structure, which is why people, it's really hard to change.

Yep. Because when you're loading something, that area is mechanically deaf, the load goes around it actually, the cells go you're dead to me and I'm just going to load the normal part of the tendon.

Can we load disorganised areas of tendon?

David: Is there a way to shift the load onto those parts of the tendon? Does tendon fatigue, is that a thing? Or is it mostly just about loading up and getting more load capacity in the parts surrounding that?

Ebonie: Yeah it's a good question. I think Keith Baar's really leading the way in this space in terms of how you might play around with changing, so he does a lot of work in isometrics and at different durations and different intensities to try and prioritise loading through that area.

So I'm really excited to see what comes out in the next couple of years. And I always love hearing an update from his lab. I think that's one to keep an eye on. And that's what I was saying, like really excited to see where we go with this. The clinical message we have at the moment is, you know, let's try and improve pain and function as opposed to structure.

But, if in five years I'm saying something different because we've learned more, that's exciting.

David: Has there been anything to show that we can put load through it or that it, we can change it in any way? In humans or even in rats or any of those sort of studies that structure can change?

Ebonie: I think there's some modeling work that's been done in relation to a combination of load and maybe some supplementation um, in a lab-based model that's shown some change. So I think there's some potential. Now whether or not that. area is as good as the rest of the tendon. We still have a lot of questions, but I think it's an area that we're going to see more of in the next couple of years.

Do supplements help?

Ebonie: But what I would say at the moment is if I bring it back to the person in the clinic, and I get this question all the time, should I be taking collagen supplementation? Listen, it's going to help your nails. It's not going to help your tendon. That little tablet doesn't make its way down and restructure, you know, lovely tendon. It's just not how it works. It's really complicated. So, you know, When people talk about supplementation, we've got a food first approach of course, with our athletes. So what we want to do is make sure they're fueling for all of the recovery and all of the things they need without probably a specific focus on any one particular tissue. But, for some of the things that are out there that are really low risk, you might consider it, but it's not going to be a magic bullet.

David: While we're on that topic, are there any supplements or is there anything that people can do peptides get mentioned a lot by patients. They're probably the big thing I get asked about the most. Collagen, hydrolysed collagen, vitamin C. There's lots of things that pop up. Is there anything that's been shown to have any positive impact there?

Ebonie: I think not in at a human level. I think there's some basic science work that's been done, which has been extrapolated, but I think it's an area that we'll hear more about. But as I said, I think

because tendon is so complex, it's got to make its way down through, not be broken down at all the levels and then somehow be distributed to the right region to then be taken up and integrated into, a complex structure in the right area of your body. We're asking a lot of these supplements and so I think, the considerations for me are, is there any risk you need something that's no risk, which is why please don't inject peptides or any of that junk into your tendons. So is it low risk? What's the cost? There isn't great evidence at the moment, so we shouldn't be asking people to shell out a lot of money and, is there some sort of reasoning or kind of mechanistic justification that I can get my head around?

Again, I'm really open to seeing where this goes in the next couple of years, but at the moment we don't have really good evidence for supporting anything outside of a good loading program, which is not the answer people want to hear. Sorry.

Avoid these in your tendinopathy treatment

David: Definitely and what about things that people need to avoid when they've got a tendon pain.

Ebonie: There's a few things to avoid.

Poking, it is fundamentally unhelpful. So think of it like a bruise. If you keep poking it, you actually keep it a bit sensitive and the pain to palpation is the last thing to get better. So I said it wasn't very helpful diagnostically, and it's also not very helpful prognostically. So don't let people keep poking it and as a clinician, don't keep poking it. The second thing, and it sounds really obvious, but don't stretch because most of our tendinopathies actually occur at the bone tendon junction, or they occur at a site of compression. So if you think about stretching your Achilles insertion, it's provocative. Think about stretching your hamstring, insertion. It's provocative.

And I say that, and a lot of the clinicians on the call will be like of course don't stretch. But if you Google it, one of the first thing that comes up is, RICER and stretching. And unless you teach your patient and your athletes about compression and avoiding compression, stretching just seems really logical.

It feels stiff. It feels tight. don't underestimate the little nuggets like the, don't poke it, don't stretch it. In terms of avoiding, it's more educating people about when to listen. So I would avoid letting people, or I would avoid encouraging people to do how much they feel at the time because you'll get your under loaders, David, that feel sore and get a bit timid and back off and get into this cycle of dysfunction. And then you'll get your overloads that warm up, feel amazing, do way too much only to be worse the next day. So my third tip would be really encourage people to listen to their tendon the day after they load and use that to guide how they load.

So avoid listening to pain during activity. I know there are pain rating scales. I think it can be confusing to get people to log their pain too often. So I personally use pain the next day. But for something like a peritendinitis, I do listen to symptoms at the time because you're just overloading that peritendon.

So it just circles back again to that differential diagnosis.

Finding the right level of running or load

David: Great, identifying of what's important when you're looking for loading and pain levels, that sort of thing. So what's an example of that? How might you guide a patient when it comes to identifying those right levels? Are we talking here about how much weight they're using in rehab, or how much running to do, or how are you using that 24-hour timeline to help to guide that?

Ebonie: You're right, it probably relates more to those provocative activities like that spring type load or that running load. So if you've got someone in the gym, because anything slow or static is really safe, I would encourage them, even if they're sore, that they go to the gym, they'll feel better for it.

So even if they've had a flare, keeping their strength in is really important.

The session that they would modify based on their pain response and their 24-hour response is their spring day. So just say you are up to skipping with them, you might reduce the volume, just say you're up to stairs, you might reduce volume or speed.

If they are running, again, you might reduce overall volume. So it's just manipulating what did I do, how did I cope? Do I need to keep it the same, go up or go down? And I often use um, emojis. So if someone is the same or better the day after, happy faced emoji. The next time you do that session, I want you to increase a little bit.

Flat-flaced emoji, I felt okay, I wasn't terrible. Repeat the session. You don't have to go up or down. Just give your tendon that load again and see what it does.

Sad faced emoji. We got a little bit wrong. Stay in the gym. You've had a little bit of a flare. What we'll do is the next time you do that session, we'll dial it back. So you don't need to be, you don't need to have zero symptoms. But what we want is stability and we want low symptoms. And I work out with people what that number is because it's really different for people. But it's more about stability. If you are 2, 2, 2, 2, 8, what did you do yesterday? I'm not worried about the twos. It's the peak. If you are 2, 2, 2, 2, 3. I might actually repeat that session.

What causes tendinopathy to develop

David: You mentioned there's some nice points about avoiding stretching there. Patients sometimes come in and they're like, yeah, I think I've got this because I am inflexible. I haven't been stretching much for years and so that's why I've got it. What's your thoughts on the things that can lead to developing tendinopathy? Are Are there any factors like flexibility, biomechanical things that actually can predispose people to get a tendinopathy?

Ebonie: Yeah, there's a systematic review that looked at this and we don't have great evidence.

And you think about why that is. You'd actually need to get a lot of data from people, follow them over a long period of time and see who got tendinopathy. I'm not doing that study. That would be an absolute nightmare. And it's the same with predicting rupture. So we have reasonable inferences around some of these things, but we are probably quite data poor because of how hard this would be to do, but we can talk about associated factors. So patellar tendinopathy for example, has been associated with having a bigger waist girth, even even in jumping athletes. So athletes that were young jumping men, but had a bigger waist girth, had a higher incidence of patellar tendon changes, increased or decreased knee to wall.

And that probably just changes again, your mechanics and your landing. But I would say your absolute biggest risk factor, if we go back to first principles, is not having the capacity for the load you're trying to put on the tendon. And so what's our biggest prevention? Making sure that we're progressively loading our tissues, that we're strong enough that we've introduced spring and that we don't have big training errors or big changes in load. So tendons are very simple creatures. They like the basics.

David: So if you had an adolescent athlete and maybe they're keen or they're pre-adolescent and they're getting more into maybe it's rugby, basketball, whatever it might be, lots of running. What sort of guidance would you give them on how to look after their tendons as they're going through that developmental stages where their tendons are growing and developing and they're laying down fresh tissue?

Ebonie: I have a 10 and a 12-year-old and I can tell you that all the guidance in the world from their mother means absolutely nothing and they don't listen. So I'm probably not the best person to ask about this because I don't have a captive audience, but all jokes aside, it's a very challenging group to modify. They're kids, they're excited, they love playing, they play all day at school, which is fantastic. They then play sport on the weekends. If I circle that back to the conversation we had about the development of the patellar tendon even though we know there are probably periods of time where you are more vulnerable to developing pathology, are we going to have any traction from the athlete, the parent and the coach trying to pull that kid out of the state team, the domestic team for a period of time just to let their tendon grow? There are bowling restrictions in developing cricketers, for example. So it's not unheard of, but I just think of, the tall, talented basketball player who also plays football, that's a lot of people to get on side that and you're not going to be very popular. I've been playing around because we've got some Sever’s going on in our household.

So I've been playing around with different loading strategies with my 12-year-old and just playing around with rate of loading and getting some pulses in and seeing how we go. So I've got an N of 1 going and I'll, I'll keep you posted.

David: For sure. You can motivate them to do it all, then you're going well..

Ebonie: Exactly.

When and how to include isometrics in treatment

David: Let's come back to some isometrics and some treatments. I want to talk to you about the role of isometrics in treating tendinopathy. So when are they a useful part of treatment?

Ebonie: I'm hoping people see the number of tools that they have in their kit.

So a really important tool is education. So teaching people about what is high load teaching people about what is safe load. So our safe start loads even from day one is isometric and isotonics. So it's a tool in your kit because it's associated with reducing cortical inhibition. I think it's potentially a tool we can use once we start to understand a little bit more about neuroscience and the changes that we have in our brain. So it's a tool that people can use before activity. They can use it before they do their gym work to reduce the cortical inhibition. It's absolutely a tool for in-season where we have few loading strategies that are well tolerated. Things where you can manipulate it throughout what you need from it.

So for example, you might be doing long heavy holds, like five, lots of 45, specifically for analgesia and cortical recovery. As someone's symptoms come down, they might ditch that out. You might go for shorter, more performance focused isometrics. You might use a quasi-isometric activity like stairs where you're actually trying to train someone in that foot strike position so that they're quite stiff through the ankle and the calf tendon complex in that very functional position.

So there's lots of ways we can incorporate it in, but what shouldn't be happening is people get that in isolation and they stay there. Isotonics are safe from the start. If someone has a lot of kinesiophobia and they're very nervous, you might start them on isometrics, but you want to try and get them into that isotonic as early as you can and then really move out those isometrics.

David: They're not the be all and end all, but it sounds like there really nice way in for people if they have some fear of movement, it can help to decrease their pain, and you find that that five to 45 seconds is often a nice way to help to settle pain.

Ebonie: Yeah, there's been a couple of studies now that have looked at the minimum dose and that appears to be quite important for the time under tension to get the changes. I think what I would like everyone to take away is that there's never going to be one thing.

Our tendon acts like a spring gets squashed against a bone, you know, works at length. If you think of the amazing athletic endeavors, there's no way we could ever just give someone isometrics or eccentrics or heavy slow resistance. So I'd like everyone to really just be thoughtful about how each of those things has a role, but. can't be all. None of those things, isometrics, isotonics or heavy slow resistance actually recover spring.

The reason why they're researched is we can give the same program to people, ask a research question and look at the outcome. That's not life. Life, people come to you not for a four week study. They come to you with a functional outcome. And so you look at the endpoint of the research. So one of the studies we did in season, the very specific question we asked was, over four weeks are isometrics and isotonics tolerated, is one superior. Now, that's not a rehab program. That's a four week in-season question. And so what no one should be taking away from that is, oh, people need four weeks of isometrics or isotonics. That was, can we add it in season on top of in-season loads? Because prior to that, the other in season study was in 2005, the Visnes study that showed that you can't add eccentric only. So yes, none of those exercises are the be at all and end all. They all need a role and they all need to be progressively loaded back to the activity that person wants to do.

David: You mentioned there before about the length of time that you're using isometrics. You might be starting with 45 seconds if you're looking for that pain inhibition effect. How do you tend to progress the time? Or is there a way that guides you in that?

Ebonie: I work really closely with strength and conditioning and so I might have a chat with them about what that particular athlete needs in terms of rate of force development. And so we might be doing something, very fast and against a movable frame. It's isometric, but it's with a very specific kind of training goal in mind. It depends on the sport. A track and field athlete is going to be really different to a basketball player, for example, but you might go very short, very heavy. Yet very quick.

David: What's an example of an exercise where you mentioned there that they're pushing really brief for like really hard. What's an example of an exercise where you're doing that?

Ebonie: If you're standing in like the force frame, the VALD ForceFrame or on the ForceDecks and you are pushing up into the rig, you're not moving it and you're getting them to push up maximally as hard and fast as you can. You're trying to train rate of force development.

So you're measuring it and seeing whether or not it's at a similar level to the sort of athletes that you train. And then if it's not, how can we train that as a strategy, trying to improve that ability, for that athlete to get off the ground really quick.

When isometrics are likely to help or not help

David: Do you find there's any difference in the tendons that tend to respond to isometrics, or people, or are there any factors that tend to be correlated with getting a pain inhibition effect?

Ebonie: That's a good question. I think I can tell you that people that have a non load induced tendinopathy, so a systemically driven tendinopathy don't get pain relief from load. Because it's actually not what's driving their tendinopathy. So if you've got someone with psoriatic arthritis and an enthesopathy or an enthesitis in an athlete until you address their systemic driver , load actually makes them worse.

And so we've seen that in our athletes. So I think the first thing is, do they have a systemic condition? The second most common thing that I see, in fact, the first most common thing that I see, if they've been incorrectly diagnosed. So particularly in the knee, patellar tendinopathy is way overdiagnosed.

It's way more common that someone has patellofemoral joint pain. So if you have someone that's really provoked with heavy isometrics on the leg extension, you have to consider that you actually just compressing their patella against the back of their knee joint and that's actually why they're not tolerating it, as opposed to, trying to do it lighter because you still think it's the tendon. First principles, It's not fast, it shouldn't be provocative for a tendon.

David: Yeah. And there seems to be like people that respond really well to them. Like I have patients, they go, that just works a charm. You know, you can do a treatment, you can get them, do a couple of isometrics to start with, see how they're responding and progress from there. And some people where they just don't seem to get a pain relieving effect at all.

And, you know, I haven't been able to correlate it with anything specifically, but there are responders and non-responders. Is there anything that's been emerging in that field to show us, you know, how we can pick people?

Ebonie: no, I don't think so, but for me it's such a low risk thing that if you try it, you're not going to make them worse. And if they don't respond, you move on or you add in isotonics or it's not like you do an injection.

It's not like you're asking them to pay a thousand dollars. Yeah I don't think it's a big deal. I think we do have, people are humans, they're complex, they respond really differently and I think that's okay. But I think, for me it's not a dangerous intervention. So I'm okay with giving it a try and seeing how they respond and if they like it, great.

If they don't, great.

Choosing the starting position for isometrics

David: and how do you go about choosing the position? Say you've got an Achilles tendinopathy or a patellar tendinopathy and you're starting them off, you've got them in that initial session. How do you tend to choose the positions that you might perform an isometric.

Ebonie: Yep. If we think of our insertional Achilles, we want to be well away from dorsiflexion because we want to be out of compression. So we'd have that person up in high plantar flexion. If we think about the plantaris that would be similar. So the plantaris compresses the medial Achilles in dorsiflexion. So we want to have someone out of dorsiflexion if they have a plantaris involvement, if they're mid portion, they can be, mid range, they can be quite plantargrade.

It actually doesn't matter. if we have someone with patellar tendinopathy. We tend to do it at 60 degrees of knee flexion. That's just because we can generate the most force through your quadricep.

How to describe isometrics to patients

David: Let's talk about how you might describe it to a patient. You're saying to the patient, all right, we're going to get you to do some isometric holds. Or how do you go about describing to the patient what to do and what to report to you.

Ebonie: We had quite a specific script in research so that, there was no bias towards one or the other. But when I'm doing it in clinical practice, what I'll say to people is I'll actually teach them about tendon load and I'll say, okay, your Achilles, it acts like a spring. As you drop down into this position, it gets squashed against the bone. We know that your tendon loves anything slow or static, so we're going to try both of these today. And it gives them that confidence that it's really safe to do. So I just describe it as slow and static. Slow or static load and I just put them in the position and away we go.

How to choose the load for isometrics

David: Brilliant.

And how do you go about choosing the load that you're going to use with them?

Ebonie: When you've done your objective assessment, after you've diagnosed them, you'll often look at function. So you might look at single leg calf raise endurance, for example. And if you've got someone who can do, more than 15 single leg calf raises, they're probably going to need additional load on a Smith for it to be heavy. So remember, heavy is relative. If you can do sort of 10 to 15, often just single leg body weight is going to be sufficient. If they can do less than 10, you might need to do double leg body weight. If they can do less than five, you're going to need to go below body weight and use a seated calf. So I use their functional assessment to guide me. And then what I do during the first set is after about 15 or 20 seconds. I actually say to people, is that really hard or do you think you could hold it all day? Because people know really early, like if it's too heavy, you'll get that early fasciculation and you can modify it within the first 15 or 20 seconds. If people say to you, I could hold this all day, I stop, I go up in weight and I go again. So it's a little bit of trial and error to give people a little bit of an idea for the patellar tendon, the average starting weight in our RCT was 27.5 kilos. So I often start at 27.5 kilos, see what they're like for the first 15 or 20 seconds. Having said that, I have ballet dancers that can do leg extension of 70 kilos, so that's highly variable.

David: That's a solid effort.

Ebonie: Not bad.

David: Not bad for sure. And so with your patellar tendinopathy ones, when you've got them on the leg extension, are you getting to do a double leg leg extension and then get them to a point where you're going to hold and then take away the other leg?

Ebonie: Yeah often that initiation just, it's uncomfortable. It's not dangerous, but yeah, just get them to take it up with two. Take away one. Same on the smith up with two take away one. Hold.

David: If people don't have a leg extension and they're looking at a patellar tendinopathy patient, what are some of the other exercise or things you might guide them with to help to load that up?

Ebonie: There's good evidence for the Spanish squat. So that's the belt that goes around the back of their shins. And then you want like a 90 degree, knee angle and then as deep as you can with the hip, but not leaning forward. The leg press is okay, but you can really unload a lot through your glute and a wall sit just isn't enough load. So sometimes people will say to me, oh, what's a good home exercise for patellar tendinopathy? Just remember the population that will have it. The population that will have it are your elite, young jumping men and they should be in the gym. It's very rare, COVID aside that we need alternatives. They actually need to find a leg extension. That's what I say to people, go and find one.

When to include isotonics in treatment

David: Fair enough. And then you mentioned before about isotonics and sometimes people are thinking about these, about performing isometrics early early in their treatment process but you mentioned that isotonics can be introduced pretty early as well.

Ebonie: I get them going from day one.

David: Okay, that's nice. How do you identify the best load for patients when it comes to isotonics?

Ebonie: If someone comes in and their function's quite poor and they can't do very many calf raises, they may not need, they may not even need a gym to begin with for the Achilles, so their body weight at home for an isometric and a calf raise might be sufficient. But you might want to get them into the gym early because you can add, the rest of the kinetic chain, you can add in a seated calf. So it depends on what they want to be able to do as to whether or not I would manage someone like that at home versus in a gym. But I would get them going on a really good quality calf raise from day one.

You know, draw a line between the middle of the ankle joint, middle of the second toe. So they're going up nice and straight. Try and get them to go to full height. Keep their knees straight, hold on for balance. It's not a balance exercise. It annoys me when I see people, with two fingers against the wall.

If you want to train balance, if you're training calf endurance, get them really stable and train calf endurance.

Plyometric & Stair loading  

David: And then when it comes to more plyometric loads or higher loads for the tendon, when do you start those, and what's your guidelines for identifying when the right time is for that?

Ebonie: So you want to move away from it being time-based, as you said, and you want to move it more into criteria based. So we might be looking at, 25 or 30 single leg calf raises, for example, before we might move someone onto something a little bit more dynamic. And what we'll start to do as they're getting towards that is we'll get them on stairs.

And what we can do on stairs is stepping on stairs with a stiff ankle on the way up, and on the way down to a metronome below 150 beats per minute. We are not putting load through the tendon. So we're starting to introduce something that's dynamic. As they get their strength up, we can start to increase the speed of those stair sessions so we can go above 150. That's starting to load the tendon. So I'll put those on the non-gym days and that starts to introduce a little bit of gentle spring.

David: We're talking about a stair climber or just going up and down stairs?

Ebonie: Going up or down stairs. Stair climber's, no good. because you don't get the descent.

David: Run us through that, how you guide patients. Say you are describing to a patient what you want them to do when it goes to stairs. What do you tell them?

Ebonie: So I'll show them because I think it can be challenging for people to get their head around this. I get them to hold on for balance. You want them on the ball of their foot and they stay on the ball of their foot. So they're about 30 degrees of MTP flexion. And I'm going up and down without dropping. I don't want the healed to drop on the way up or on the way down and I put it to a metronome so that I'm making sure I'm, reducing cortical inhibition, but engaging the tissue that I want and I'll get them going for a few minutes. And then as a progression, I can increase either the time or the speed depending on the athlete. So if it's an athlete that wants to run, 15 kilometers, I'll increase time. If it's an athlete that wants to sprint, I'll tend to increase speed.

David: That's a really nice introductory plyometric exercise where they're really you're incorporating the isometric along with some actual fast loading. So. What are some examples of ways you might progress that with an Achilles tendon?

Ebonie: You can progress that right up through speed so they can end up sprinting up and down stairs and you can go up two or three stairs at a time.

So that really trains power, But always come down one for safety. The reason I really like stairs is I can use it lower level people because it's quite functional, you know, you still want to be able to get up and downstairs as you get older safely, and that uses your Achilles tendon as a spring. But also our elite athletes, you know, we can just increase the pace of that and get them doing really high load activities. And then that's a really nice transition into then doing, you know, your horizontal skipping and more of your track and field drills into more your running stuff.

How long should isometric holds be?

David: One other thing I wanted to come back to, just with the isotonics too, you mentioned that, time under tension. When it comes to your isotonics, how do you tend to guide patients about how long to spend? So they're doing a calf raise, what's your guidelines with that?

Ebonie: If you look at your bigger joints like uh, leg extension leg press, we'll do, um, three-second concentric, four second eccentric. So it's a seven-second time under tension for four, lots of six. And the reason I did that David, is that where it's at exactly to 5 by 45. So I could actually match the groups for time under tension, but then when you look at the hypertrophy literature that actually supports the muscle literature. So that's the sort of guidance I give.

Patient advice & discussion

David: Any other sort of guidance you give to patients when they're performing, loading, whether that's isometric, isotonic or more plyometric stuff?

Ebonie: Again, just really encouraging people that if they turn up to the gym and they're a little bit stiff or sore that day, just feel really confident that you're giving the tendon a load it loves when you're doing your gym work. So keep the gym work in, even if you've had a flare. And when you're doing your more plyometric work, again, don't deviate from the plan. Don't do more because you feel better that day. because you'll, you'll pay for it.

David: Patient's coming in, they've got Achilles tendinopathy, patellar tendinopathy or some other sort of tendinopathy you've mentioned there before about how you might describe to them, why you're doing the exercises, but how do you tend to describe the actual tendon process and what's going on in the tendon and the whole recovery to them. Physios are out there, they're treating someone that comes in. Give them some tips on how they can describe it to patients in a way that helps them and de threatens it and makes the patients feel positive about it.

Ebonie: I borrowed David Butler's words. I try and meet them at their story. So I want to know what their understanding is. Have they been told there's a tear? Have they been told it's hanging on by a thread, because what I want to do is meet them and really try and work out the language that they have around their tendon and build that kind of self-efficacy. I'll ask them what they've been told or what their understanding is of what's been going on. And I'll do that regardless of how long they've been seeing someone, if it's a second opinion. You really want to know where they're at. And I'll be really honest with people, we actually don't know what drives pain in tendons. So what we are looking to do is not change how your tendon looks. It may not look any different.

So we're not going to keep imaging that. What we know is that your Achilles tendon has adapted. Do you see how it's an increase in AP diameter? I'll draw it for them. So I'll say, here's your area of that's not listening to load anymore. Here's the surrounding normal tendon. Here's a completely normal tendon.

Do you see that you have more load bearing tissue than a completely normal tendon? So what we have to do is get our load right for the tendon, get your muscle really strong so that your tendon has something to pull on. Do some cool stuff for the brain and you're going to do really well. So it's de threatening the pathology, but not just dismissing people and really making sure they have confidence in their bodies.

David: And what are some of the most common questions you get from physios when it comes to treating tendinopathy?

Ebonie: A big one that I get is around differential and understanding load. So really, is it safe to do gym, work? How do you pick a plantaris? They're the common questions that I get, I do get questions about, what's better, an isometric or eccentric.

I hope you feel like we've covered that really well. That isn't the right question. It's what's the right loading at the right time for that patient. But a lot of the questions, yeah if people, feel confident with understanding tendon load, I think that helps to recognise if you think the person's got tendinopathy. Loads you need to take away initially, what loads they can start with and what you need to get them back to. I feel like if you understand load, you really have a good understanding of working through tendons.

David: Any other messages you want to share with physios out there about treating tendons.

Ebonie: That they're really obvious. If you think you've got a tricky tendon, you've probably got a case of differential diagnosis. So the tricky patellar tendons I get to see, where people are trying to apply a patellar loading program and they're not doing well, it's not a tricky tendon it's patellofemoral joint pain. Same with the Achilles, your tricky mid portion Achilles, that they're not even pointing in the right spot.

It's probably the peritendon or a plantaris. So don't be afraid to go back and revisit your diagnosis and just see whether or not it's still behaving, particularly if someone isn't doing well or they're getting worse with your exercises. If someone isn't doing a loading program, that's really valuable information.

You know, If they're worse with calf raises, that gives you so much information. That non-adherence is really helpful because you've got your diagnosis wrong.

David: And then if people are experiencing that and they're thinking, okay, maybe we've got a peritendinitis or something like that going on, how do you tend to approach those?

Ebonie: So the thing about the peritendon is movement is the provocative load. So you want to reduce movement as best you can. That might be encouraging people to get in a shoe with a really high external heel. So you're not going through as much movement. You want to take them off their provocative load.

So their swimming, their cycling, their rowing, whatever it is, I might start them on stairs because it's quasi-isometric. You're not shearing the peritendon over the tendon. So it's really well tolerated if they do it well. There are some medical interventions like the half Hirudoid, half Voltaren wraps, but they need to be medically prescribed.

Physios can't give those. But they're the kind of options you want to try and settle down the adhesions between the tendon and the sheath.

David: That's described that really nicely. Fantastic. Anything you want to add before you wrap this up Ebonie.

Ebonie: No, I think that's been a bit of a whirlwind of tendons. I love it

David: For sure. You've shared a whole bunch of information, lots of great stuff, and I think there'll be a lot of physios out there that are going to benefit a lot from you sharing how you're going to approach that, and how you incorporate isometrics along with isotonics and more of your higher loading plyometric and, and spring based activities for tendons. And so yeah, really appreciate you coming on and sharing all that with us.

Ebonie: Hopefully it's helpful for people and really practical. Thanks for having me.

David: Where can people find out more about you and what you got going on?

Ebonie: Well, I'm not Twitter or Instagram or any of the things that the cool kids are doing.

But hopefully we will keep putting out, great research and I'll keep doing things like this and yeah that's probably where.

David: Fantastic. You've got a lot of great stuff on researchgate. so I've been, uh, having read all your articles that you've been involved in there, so you've got lots of great stuff that you've been publishing which is awesome. We really appreciate all the research that you've done and the efforts in sharing that with us. So yeah, thanks very much.

Ebonie: Awesome. Thanks for having me.