- Welcome to Reading Rehab, a journal club podcast where we uncomplicate current peer-reviewed articles and musculoskeletal rehab. Designed for busy students and professionals, our mission is to keep you informed and up-to-date without the hassle of sifting through research papers. Join us as we break down key studies into easily digestible content. Perfect for your commute or downtime. Our goal? Equipping you with the tools and knowledge to confidently approach a variety of clinical cases. Enjoy. - Welcome back to another episode of Reading Rehab. I am Mike Brown joined by. - Brian Gardner. - And Pat Healy. - And this week we are talking about from tissue to system, what constitutes an appropriate response to loading. This was published in sports medicine in 2024, September, so relatively recently. And it is a narrative review article. Yeah, let's hop right into it. First thing that, I mean, we talked about author is, it is long, but there are like some good points. I feel like it's kind of easy to get lost in the weeds with this and essentially each section could be like very long. So I appreciate that it's not like a million pages long, but it's still like 15 or something. - Yeah, I felt like it did a well job of like summarizing some bigger topics, such as like muscle adaptations, tendon, bone, and they even talked about like cartilage adaptations. I don't think any of it was super like new information, but I think it's like a nice refresher on things. I did like how they noted within the bone adaptations that endurance runners who only run had lower bone mineral density than those who strength trained. And also advised that one coming back from like a BSI to be pain free during daily activities for five consecutive days before commencing like a return to run. You know, we were saying off air like I kind of like the whole bone adaptation section itself, but I think that's just my bias coming from being a running background. Oh, and before we get away from it, the cartilage adaptation. I loved how they put the last sentence, currently no strong evidence that strenuous exercise increases risk of OA in healthy joints. Absolutely love that. And then also how for like individuals with OA that they reported lower pain and disability symptoms in those undergoing quad specific exercises than those in general lower extremity exercises. So get your beefy quads up. Lots of stuff to comment on there. To piggyback on your favorite sentence of the of the cartilage adaptation one too. I actually really liked the sentence before that as well. Whereas studies or some studies have shown a greater prevalence of hip and knee osteoarthritis in professional runners and sedentary individuals. 13.3% and 10.2%. So like they're relatively similar than in recreational runners, which is 3.5% but it's not possible to determine if these associated incidents are causative or confounded by other risk factors. I just I've at least seen similar research and thought processes around this too. Obviously with my running bias as well that like there's kind of almost a sweet spot of running for cartilage health. We're too much like what professional runners like professional runners often run a lot, especially thinking like marathon runners. So there's probably too much where you could talk about like the wear and tear hypothesis with osteoarthritis. But then with recreational runners actually having less of a prevalence than sedentary individuals. Like it's suggesting there is some sort of optimal amount which we currently don't know. But I find that research really interesting. - Yeah, I feel like you're like what you just said about like the optimal amount we don't know is kind of like my biggest takeaway at the end of this paper where the whole point of this paper was to discuss like localized tissue timeframes based upon volume and intensity of work as like different parts of the body are going to adapt based on activity and stress you apply, but like muscle, tendon, bone, cartilage are all gonna adapt differently based on like what that load is. And so that's like kind of what figure one in this is trying to like summarize. But if you look at the top end of it where it says 72 hours and above, they don't really have like rapid eccentric muscle contractions within like sprinting, but then it's also paired up with high CNS stress such as like very high interval training for like also like sprint training. But they noted in the limitations that like most of the research only goes up until like this 72 hour window and there's still more research to be had of like longer adaptations that might be needed for some of these systems to respond to the stress. So like one example they did pepper in here had to do with strength training I believe where they said that the like creatine kinase was elevated for a good eight days after like a very strenuous bout of eccentric training. And that's like the only one that was mentioned in here that like went beyond that 72 hour window and for people who don't know the creatine kinase is like your kind of like metabolic indicator of tissue like breakdown and just like overall stress from the muscle that's released after resistance training. At least that's my knowledge of it. - Yeah, I don't have more to say about that. - No, I think what you said Pat just to kind of piggyback off you is in the beginning they just say is it possible for practitioners to optimally load one tissue but sub-opically load another which I think looking at the programming and programming is probably one of my favorite topics to talk about basically they're coming down to that you need a well rounded program to be able to get certain adaptations is what I've taken away from it at least the programming because they do go through it through the specifics but they do go into programming at the end which is great and then I like how they kind of go into how you monitor that programming which is a totally different again like we had mentioned this is a really long article so they could have made this into a few different sort of like they could have cut it into a few articles which would have been nice and they could have spent a little bit more time but I appreciate them trying to just narrow down some a few little things about whether the internal or external load monitoring the subjective wellness is at the end but then also getting into the programming side of it as well. - Yeah like kind of what you're saying I feel like that was a big task for them to take on for this one article is like the bulk of it was looking at you know the different tissues and how they responded to different loads but then like what you're saying they were... - Hey there listeners, Brian here. We hope you are enjoying this episode thus far. We just want to take a quick break to say thank you for tuning into this episode of Reading Rehab Podcast. Your support means the world to us and while you're here we'd love to hear your thoughts. Have questions, feedback or topics you want us to cover? Drop us a line or hit us up on Instagram at Reading RehabPod and don't forget the best way to keep up with current episodes is subscribe to this channel. So hit that follow button in your favorite podcast app so you'll never miss a moment. Plus if you're enjoying what you're hearing leave us a review or share this podcast with your friends. It really helps us grow and reach amazing listeners just like you. All right that's enough for me. Let's get back to the episode. - I don't know if you know... Okay there you cut out a little bit for us but hopefully that's a seamless transition for the listeners. The listeners don't even realize that you cut out. Hopefully. - But yeah so what I was saying is like kind of like a big task for this article to not only look at like the tissues and that whole side of it but then also talking about like the different ways to monitor how the athlete is responding to load. And then also they peppered it in at the very end where they talked about the final considerations different like comorbidities that can affect these adaptations. And I would have liked that even to be a little bit more extrapolated on. I think that's just coming from working with individuals who have a lot of comorbidities. So like for example, obesity is gonna increase your risk of tendinopathy, BSI, in arthritic degeneration and then like diabetes, RA and like high cholesterol is risk for like tendinopathy. It's like that's good information and no I just wish they had like more on it but that just would have been more on this already pretty extensive paper. So. - Yeah 'cause those could all be papers in and of themselves. Like what is the like tissue healing time which they do talk about like general tissue healing times and that's where figure one comes from but the tissue healing times for each of you know muscle tendin cartilage bone in diabetic populations. Like that's its own like its own narrative review there because we can't assume that they're all totally the same. Yeah, I really liked that section as well. - Well I think it's also important to note that figure two was a really good one for me at least. And I think that goes based on the individual responses to tissue loading because they go through how to do externally load monitoring. So what did the athlete or person do? And you can, this is just a general, they use athletes in this specific situation. So external loads, so they kind of reference a lot of a couple of different things like IMUs, GPS, pedometers, local positioning systems and then they go through and look at the internal load. So how did the athlete respond or person respond to that load? So if for me it's kind of like do the thing, how did they respond to it? And then they go into subjective wellbeing. So how did that person cope with that load? And I know for me personally like when I'm dealing with like return to play is I look at it as like how did the person feel during immediately after and then 24 hours after just to allow the see, okay how did that person cope with that certain stimulus that we're introducing? And then they look at it a fourth sort of thing, objective measures of physical readiness. So like resting heart rate HRV. So stuff similar to what we chatted about last episode and wearables. They also go into like force and power, isometric strength, counter movement jumps, sheer wave, ultrasound tissue characterization. So they go into like how did they respond and then did that make what you wanted to do? And then they kind of go through that process again it's just like one big circle pretty much. So I actually really like this sort of thing, especially if you're looking at it of, okay I have a tendon. I introduced this, what did this person do? Say we did isometrics, how did that person respond? Oh they had less pain, great. And then how did they respond 24 hours? Oh they were sore. So did we add too much too soon? Or is that what we were actually looking for? And then did that sort of respond? They actually have more force output after we retest them. So I think that's a good way to kind of simplify. Again, I think we try to, we take all this information and research and we tend to put it too complex. And I think if we can just simplify sort of tissue adaptation, I think it's more beneficial for not only the individual you're working with, but as a practitioner as well. - Yeah, and I feel like that process, I think obviously the reason that they had figure two, like after figure one is because that is also informed by our expectations for the stress that we're placing. So for example, like I think it's worth going through figure one in more detail, but just as one example, they have isometric muscle contractions in theory. The like tissue healing timeline or the recovery duration as they put it in isometric muscle contractions on muscles is four to eight hours. So in theory, if you do some isometrics with a patient or client, the next day they should be totally fine after that. So then if you are doing this, okay, so we know what the external load is, then we check their internal load, like we check these physical readiness, the subjective wellbeing. And if all of those don't match up, then we know that's another conversation we can have with them. Like, okay, are you getting, is the fueling right? Like, are the other aspects of recovery right? Like fueling, sleep, stress. And then if they're not, then that's something actionable. If they are, then that's something we need to look at our own training is like, okay, did I program something else in? Like, okay, we were doing isometrics for the quads. And I thought that was all the quad loading we did, but actually we did like sled pushes or something as a warm up and maybe that was too much. Like something like that. I guess where understanding these recovery durations can then lend to the critical thinking process through that whole athlete monitoring model, model that Brian just described. - Yeah, I mean, I actually do. I mean, it gives you a sort of good foundation, just this figure one, just to understand 'cause it's also gives you the ability to kind of put expectations for the patient of like, let's go for cartilage, for example, they put walking and running with less than 30 minutes of recovery duration. So it's that conversation of having, and I'm just using this 'cause we, I mean, I see a lot of people with OA and explaining to them about getting up and walking pretty frequently throughout the day is gonna be important. So it allows you to have some more to stand on to enhance that person's ability to understand like, walking is a good thing. It can help and it's going to keep them active, especially if it's someone that's very sedentary and they have that sort of fear of, oh, if I do too much, it's gonna make my arthritis worse, but in theory, it technically won't. - Yeah, I, the only one of these that I'm actually curious to hear your guys' thoughts on is in bone, they have repetitive bone loading. With like slow running, with four to eight hours recovery between bones, but then they have bone centric activity, like plyometrics at 48 hours. And I'm just, I'm curious, I guess, when I program bone, like osteogenic activities like plyometrics, I typically at the very least do a daily frequency on like somewhat higher intensity, like doing single leg hops ideally forward backwards, I decide at least a daily frequency, sometimes twice a day if like they're at that point for the bone loading. And so I guess my question is at what point do you go from this repetitive bone loading, like slow running, like is our single, is like two sets of 10 single leg hops, would you consider that repetitive bone loading or this bone centric plyometric activity? 'Cause to me, that's more like repetitive, I guess it's kind of like a mix of both, but my expectation would be that you would be able to recover from single leg hops in that four to eight hour range. - I mean, I think a single leg hop is a very low, I think it depends on where it sits on your spectrum of plyometrics. I think that's where you have to define like, is a single leg hop really that intense? Because again, on the Y axis, the intensity is really high. What I would consider something that is bone centric and we'll keep on the theme of single leg is a single leg depth drop jump. And to be able to have an increased force or an increase in intensity would potentially elicit more of a like damage to the tissue to that would require higher or longer time to recover. That's where I think it's just defining your specifics of within that plyometric or that repetitive bone loading sort of continuum in my eyes. 'Cause again, slow running is still technically plyometric in nature, but how much like force is going through that sort of, I guess, spot that you're running on. - Yeah, I also, again, just 'cause I like the nuance of running, to me, the slow running, it also depends on like the intensity is the pace, but it also depends on the duration too, because if you're going out and like, I guess the way this could read is, oh, I can go out and run like at a slow speed for an hour and my bones are recovered four hours afterwards. But if I do a couple depth lands, I need to wait 48 hours before I can do any sort of bone loading again. - I think that comes down to like that thing we talked about prior that figure two is how does that person respond to that sort of, that intervention? Because someone that is fresh off of a stress reaction may not tolerate it as well as someone that has been like getting back into those bone centric activities, but again, does that height of that drop, that drop increase causes the same sort of? So I think that's where it goes in. And I actually, a lot of these also have a lot of crossover too, as you look through it, it's like, well, why wouldn't rapid eccentric muscle contraction be a sprinting, be high intensity tendon loading? Or why would plyometrics not be considered a tendon loading activity? So I think there are, I think they do a very good job of trying to like give common themes, but I think a lot of these things are very like crossover ask if that makes sense. - Yeah, for sure. I think they acknowledge that based on saying it's like somewhere within like the rehab portion, where they acknowledge that you as a practitioner working with athletes are probably looking for sport specific adaptations, such as like strength and power, but then there's also like these tissue specific adaptations. And I think when talking about like things like sprinting that are very much like performance enhancement or like performance centric kind of ideas, they are gonna have like what you said, Brian, like a multitude of tissue adaptations that go along with it. I think that kind of plays down into the idea of doing both very athletic things that are unconstrained because you're trying to develop athletic qualities, which are then going to also hopefully improve a multitude of different tissue types. But then also if you're working within like the rehab field, you're probably working with someone who's injured. So you're gonna have to probably pair that up with something that's a little bit more constrained that is within like these actual barriers of what tissue you're actually targeting, you know? So it's kind of along like that spectrum of like the rehab to performance and how like when you're in like that, what we might quote unquote say like mid to late stage, you're gonna be seeing some like bleed over the two of doing both like unconstrained things that are pretty athletic and constrained things that are quite specific on just like tissue source kind of adaptations. - Yeah, I mean, I think you get in, you're kind of talking through in my own head and this is again, my head is very busy. It's-- - And all the demons. - You're looking at morphological versus neuromuscular in those sort of situations. I think they could have put in maybe potentially a way for it, a fourth dimension to this graph. - Whoa. (laughing) - Basically watching interstellar. (laughing) - Basically looking at it. Okay, within these sort of constraints of intensity, volume and recovery, which ones are more focused on like a neuromuscular and versus a morphological end? 'Cause you're gonna see like your bone loading and say your tendon loading being morphological and cartilage loading versus like you're talking about like sprinting high CNS stress, you're gonna get a little bit more that neuromuscular sort of adaptation more than you are morphological. - Yeah, that's good point. I think I guess something I'd add to what you guys have said too, is that like it's almost, this figure is helpful in that you can do the same exercise. For example, I like the like drop jump or example as like you can do that with multiple different intentions for it. Like depending on how the person presents, it's like, okay, you are post BSI, we've been working up, we wanna intense plyometric activity to load the bones. Or, oh, your post, patellar tendonopathy, we want a high intensity tendon loading to the patellar tendon. And so it's same exercise, different justifications for it. And I think that's one of the nice parts about this too. And then this, again, this just gives how long you should take between programming that again. So like what a good thing to take away from this is like, okay, you're doing that drop jump exercise. Let's not do that with high volume at a daily frequency. Let's do that relatively low volume, taking at least 48 hours in between if you're looking for the rapid eccentric muscle contraction, maybe you wanna do 72 hours in between them. - Yeah, I mean, I think this is also good for those that create home exercise programs because we always say, oh, just do it daily. Just do it this many times a day. This actually gives you some sort of like breakdown of like, oh, I could probably do isometric muscle contractions three or four times a day. Oh, you can like, you want cartilage, things like, maybe you go walk for every on the hour for 10 minutes. But if you're in that sort of later stage, it's like, oh, now we're programming, say sprinting, well, maybe we should sprint once every three days or if we're doing, and this is the nice thing they go through high intensity tendon loading versus high volume loading. It seems like you can do more volume and having like less rest in between. So they put it under that 24 hours. So it's like, you could do a lot more volume tendon loading than you can intensity or high intensity tendon loading. So giving that sort of like thing, okay, well, you're doing probably some submax volume loading. I could probably do that every day versus like a really high effort, high intensity tendon loading. Like you might want to wait two days in between. - Yeah, that's all like to go back to like your, how you were talking about programming. Like that's how this is going to be so useful in programming, like knowing how you want an exercise program to adapt. That's a lot of what I do in my clinical practice is like we start out at things that are at a daily frequency because generally they're all the everything, I guess in those three rows from 24 hours or below, maybe there's like it's hard not to do some concentric muscle contraction. So you just make sure it's not an intense concentric muscle contraction. Which the higher intensity concentrics are in the 48 hour one. But then eventually going to a more plyometric and heavier strength focus once their tissues are calmed down enough. But we, I still in de-emphasize a daily program but still have some of those things in the daily program in the first place. So like maybe instead of having, I don't know, five exercises, it's like two exercises that you're doing daily and then there's four exercises in a every other day or like two times a week sort of thing. - Yeah, I think you also brought up a good point that they had in the recommendations for practitioners. Where you said waiting for whatever it is to calm down before like advancing to something that might be every other day or even less of a frequency. Where they said when presented with an injury, rehab professionals are encouraged to consider typical tissue recovery time frames before initiating training programs. And so so far we have mainly discussed about like how do these healthy tissues respond to these stresses? And like kind of going back to what we said very early on how this article could be multiple parts 'cause like there could be a whole other part about like what's the general recovery timelines based on current evidence for like a muscle injury or tendon injury, like bone especially is so multi-factorial based on like where it is and all that cortical versus trabecular and all that stuff. And so especially being like rehab professionals recognizing that that's also gonna play in a lot to how you're going to implement these different like loading paradigms and all that. - I can't really give a good answer on like many of these right now, just because it is, you know, so dense I feel like but might be something to look into for future episodes. - Yeah, definitely I will recommend to the reader that they go in or to the listener that they go and read this article too. We said it's long but there is a lot of stuff that we really like we didn't talk about at all too. So it's definitely worth a read. - Yeah, I think one thing we haven't talked about that I found very interesting 'cause I did not know this. I would be interested to read the article that did this study but essentially they immobilized healthy individuals to see like what's the atrophy rate based on like immobilization of a muscle and they had it that the muscle atrophy at a rate of 0.5% per day. I don't know what that percent is. I don't know if that's like cross-sectional area or just overall like circumference but then they said the greatest loss of muscle mass is in the initial one to two weeks of inactivity. So in my mind, get someone on BFR immediately. - Yeah, they do talk about BFR. - They talk about BFR as well. - Load, load, load. - Which yeah, I don't think we have to go into like everything with the BFR again too. Like just looking at time, I don't, we could spend another 30 minutes on this article I think. So again, I'll just recommend that if you, if you are craving more information, check out the link to the article in the show notes. Yeah, anything else before we like any last minute things? - If you wanna actually like read the article, try to get it through your local library or an individual who has access to this stuff 'cause this article is behind a paywall. So yeah, unfortunately. - Unfortunately. - But yeah. So this has been another episode of Reading Rehab. As always, if you enjoy what you listen to, please leave a nice review on Spotify or Apple podcast or wherever you listen to podcasts and follow us on Instagram @ReadingRehabPod. Thanks. (upbeat music) (upbeat music) [MUSIC PLAYING]
