Optimizing Tissue Stimulation and Adaptation through Load Variation

Dr. Mark Gallant // #ClinicalTuesday // www.ptonice.com

In today's episode of the PT on ICE Daily Show, Extremity Division Leader Mark Gallant discusses using isometric exercises for more than just pain relief including newer research emerging that isometric exercise does cause structural adaptation. Mark also discusses key points important for successful dosage of isometric exercise in the clinic.

Take a listen to the episode or check out the full show notes on our blog at www.ptonice.com/blog.

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EPISODE TRANSCRIPTION

INTRODUCTION Hey everybody, Alan here. Currently I have the pleasure of serving as their Chief Operating Officer here at ICE. Before we jump into today's episode of the PTI Nice Daily Show, let's give a shout out to our sponsor Jane, a clinic management software and EMR. Whether you're just starting to do your research or you've been contemplating switching your software for a while now, the Jane team understands that this process can feel intimidating. That's why their goal is to provide you with the onboarding resources you need to make your switch as smooth as possible. Jane offers personalized calls to set up your account, a free date import, and a variety of online resources to get you up and running quickly once you switch. And if you need a helping hand along the way, you'll have access to unlimited phone, email, and chat support included in your Jane subscription. If you're interested in learning more, you want to book a one-on-one demo, you can head on over to jane.app.switch. And if you decide to make the switch, don't forget to use the code ICEPT1MO at sign up to receive a one month free grace period on your new Janex.

MARK GALLANT All right, what is up PT on Ice crew? We got Instagram, we got YouTube. I'm Dr. Mark Gallant, lead faculty with the Ice Extremity Management Division alongside Lindsey Huey. Cody Gingrich coming at you here on Clinical Tuesday. What I want to talk about this morning is isometrics beyond the pain. So isometrics are obviously a muscle contraction type that have been around since the beginning of time, really. Since humans have existed, we've had to hold things and carry things isometrically. And the popularity of isometric exercises has come up and gone down and come up and gone down as fitness trends and rehab trends always tend to change and the last decade we've been in a period where isometrics have been on the up for the last 10 years and a lot of that has been because of the research of Ebony Rio out of Australia where in 2015 she took a group of volleyball players and figured out that if we hold long hold heavy isometrics we get both cortical pain inhibition and a subjective decrease in pain. Well, that study has been looked at a handful of times over the last nine years since then. And sometimes it shakes out just as ebony Rio found in 2015, 2016. And other times we see that it does not have the same wonderful, incredible pain reducing results that we're all hoping for. And really the reason for this is pain is wildly complex. So if you do the same study that Ebony Rio did with her volleyball players, five sets, 45 seconds, 70% of their one rep max for a two minute rest, and the group of people ate something different for breakfast that day, if they did not get as good of sleep as the other group, if they are incredibly stressed, if their soccer coach yelled at them, a million different things could have possibly happened that are going to impact that person's symptoms overall. So despite pain being multivariable and very complex and maybe not being the 100%, isometrics not being a great, they're still great, not being a 100% reducer of pain every time like we saw in that Ebony Rio study, we've talked about on this podcast. ISOMETRICS ALLOW FOR THE CONTROL OF MULTIPLE VARIABLES The reason we're still gonna use them is the isometrics control for so many of the variables that are challenging when someone is injured or early on in their rehab process. It controls, you can control the volume easily, five sets of 45 seconds or four sets of 30 seconds. You can control the position. Is the shoulder flex? Is the shoulder down at neutral? You can control the amplitude of motion. So isometric, there is no amplitude. It is, it's exactly still. You can control the load easily overall. That load's not going to change as they're doing the motion. and you control the speed really well because it's isometric. So there is no speed once that object gets into the position or the joint gets into that position. ISOMETRICS: TREAT THE DONUT & THE HOLE Beyond those things, there's more exciting research that has been coming out that gives us even more reason to keep isometrics in our rehab plan, especially when it seems that the tendon and ligament are involved in that person's pathology or the injury. Out of Keith Barr's lab at UC Davis, California, they are now showing that it seems, with isometric, that we can indeed adapt tendon and ligament tissue and lay down new collagen. So classically, we always thought that the catchphrase, treat the donut, not the hole. Treat the donut, not the hole. So what we believed was that you were adapting all the healthy tissues around the degenerative or injured area so that that person can get back to their activities and you're not gonna be as concerned of healing or building back up the degenerative area. And we believed it could, it was possibly, that it was not even possible potentially. And what Keith Barr's lab is now showing, that it does seem that with long hold heavy isometrics, that we can lay down new collagen in these areas potentially. Now this is all new and exciting research, so if it doesn't shake out perfect, we'll adapt with the times. Keith Barr's lab is exciting because what they are able to do that other labs can't is they are able to engineer tendons. So they create a bunch of tendons and ligaments that they can test in all sorts of wild ways because they're literally manufacturing them. Once they get something that's cool or seems beneficial, then they move that same technique or same intervention onto rat or mice studies. Once it looks positive in the rats or mice, then they move it to a human trial. So they're doing this three-tiered system where they're getting a ton of volume from the engineered tendons and trying all sorts of crazy things. Then they move it to rat and mice. And then once they really feel confident, they can move this into human studies. And what they have been showing is through the processes of stress shielding and stress relaxation, that it does seem that we can lay down new collagen and adapt these tendons. ISOMETRICS & STRESS SHIELDING What stress shielding is, it is the ability for your healthy, non-injured tissues to take on a majority of the stress to protect the unhealthy or injured area of a tendon or ligament. So it's a wonderful protective mechanism for back when we were foraging for food or hunting or having to outrun predators, that the healthy part of the tissue would take on more of the loads so that you could keep moving to either get food or stay away from them. This is a great process to keep us alive, not a great process for adapting tissues. What we really want instead of that stress shielding is some stress relaxation where the healthy injured or the healthy uninjured part of the tissue starts to relax a little bit so that we get some load or some stress into the injured area. When we get that stress into the injured area of the tissue, it's gonna create a cascading signal to the nervous system that says, hey, we need to lay down new collagen, we need to adapt to be able to remodel this tissue area. The easiest way to explain this is an analogy that Keith Barr commonly gives of two individuals playing tug-of-war together. So you've got two teams of two playing tug-of-war, they're relatively evenly matched. Let's say for this case that it's Mitch Babcock and I. So for those of you who don't know Mitch Babcock, he's an OG instructor for our management of the fitness athlete. Mitch is over six feet tall, over 200 pounds, big strapping muscular guy. I am 5'7", 165 pounds. If Mitch and I are on the same tug-of-war team, early on he is going to carry a majority of that load for the team. He's going to take on most of that stress because he's such a robust human. If the other team is evenly matched, at some point during that tug of war, Mitch is going to either fatigue out or he's going to have to start to relax a little bit to start to conserve his energy. At that point, I am going to have to take on some higher portion of the stress or load. Once I start to take on that higher stress or load, my nervous system is going to start talking, going like, If this is the type of thing we're going to start getting into, we're going to have to adapt. It's the same with our ligaments and tendons. As that healthy area starts to relax or fatigue, then what we're going to see is that the injured or unhealthy areas have to take on a load. And then again, that's going to start that cascade of the nervous system to remodel and adapt those tissues. What we're seeing is that there's a few things that need to be true for this to happen. It has to be long enough duration. So that has to be held long enough, the load, so that it gives the opportunity for the unhealthy, for the healthy tissue, excuse me, and robust area to start to relax a little bit. So long enough load where the healthy areas of tissues begin to relax. It has to be a heavy enough load to create some sort of stimulus. If the person feels like it's easy and they're not having to put out a lot of effort, it's very likely that the healthy portions of the tissue are carrying all the load And it also seems to work best when that tissue is at length. So when those tendons or ligaments are at their most lengthened position, so extended elbow, dorsiflex ankle for the Achilles, bent knee for the patellar tendon, that tends to be where it works out best. KEYS FOR DOSING ISOMETRICS APPROPRIATELY Now, there's some keys to this depending on how robust the human in front of you is. The more robust that individual, the longer the heavier and the closer to length that we need to perform those holds. So if the person is healthy, you may need to go beyond a four sets of 30 seconds. So four sets of 30 seconds tends to be this minimum amount of time that has been shown to create this stress relaxation. If you've got that really robust person, if you've got the Mitch Babcock, they may need to hold five sets for 45 seconds. Now there does seem to be a ceiling of about 10 minutes of tendon loading, seems to be this area of diminished return. So if you go beyond 10 minutes, then you need to wait six to eight hours to reload that tendon. Somewhere between four sets in 30 seconds, five sets of 45 seconds, adjusting that depending on how robust that individual it is. It has to be heavy enough again to where that person feels an effort. So if you've got someone who's deconditioned, they have not done as much exercise recently, you can create this stress relaxation with relatively light loads. If you've got the Mitch Babcock that's been lifting weights since he was 12 years old, you're going to have to load that tissue a bit heavier to create that adaptation. It has to be a high effort load. And then the final piece is we see now that tendons and ligaments tend to adapt better from an actual structural standpoint if they're held at length. So again, for the elbow, is it extended? For the Achilles, is it dorsiflexed? For the knee, for the patellar tendon, is the knee flexed? Obviously, if someone is symptomatic, it's going to be more challenging for them to get in these positions. What we do in this case is we get them to the most length that they can tolerate for that four sets of 30 or five sets of 45. And then as time goes on, we progress them to a more lengthened position overall. If you all have been following ice for a while, a couple years ago, Joe Hanksco did a wonderful virtual ice on medial elbow tendinopathy. And one of the key exercises he looked at was wide grip biceps curls to help out those medial elbows. And if we look at this, it's a wonderful exercise for exactly what we're talking about for medial epicondalgia because when you're in that wide grip bicep curl, you are holding that during the max eccentric portion, that elbow is at a ton of length, they're in a relative wrist flexion, it's gonna be a lot of stress to that medial elbow. You can take that same exercise, do it isometrically, four sets, 30 seconds, and it becomes a wonderful thing to adapt the medial elbow, ligaments, tendons, and tissues overall. Last thing that we wanna talk about is anti-inflammatories block stress relaxation. So if that person takes anti-inflammatories early on, everything we discussed the last 10 minutes becomes much more challenging. When there's inflammation in the area of the tendon, it creates a natural stress relaxation where the healthy portions of the tendon are not gonna be able to take as much stress and load, and you're gonna get a little bit more stress and load to the injured or unhealthy area. So if that person takes an anti-inflammatory early on, they're not gonna get that benefit of being able to take less load, less strain, and get some adaptation to the injured area of the tendon. So if folks can, we tell them to use natural processes. Use your cardio to pump inflammation out of the area. Use eating healthier foods that are not going to block the entire inflammatory process. They're just going to decrease some of the inflammation and still allow for that stress relaxation. So overall, if we're trying to adapt tendons, to lay down new collagen, to remodel those tissues, We want it long load, four sets of 30 seconds, five sets of 45 seconds. We want it heavy enough to overcome that stress shielding. So it's a high effort lift and we want it at length of that tissue. So again, if it's the elbow extended, the ankle, dorsiflex, the knee, if it's that patellar tendon bent, whatever the deepest amount of, of length of that tissue that we can, that's where we want to go. Hope this helps. We're gonna come back on here in a few weeks and talk about isometrics for adapting muscle output in the central nervous system. Hope to see you all on the road. Head on over to the ICE app or the ICE website. We have a ton of offerings coming up for extremity management all over the company. My next one, I'll be in Dallas, Texas in June. Hope to see you all there. Message us, comments, love to chat more about this. Hope you all have a great Tuesday.

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