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On today's episode with Chris Juno, we discuss a case of a Cirque performer who tore her subscapularis and lat insertion during a performance.
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Chris is an expert in measuring force, and in this podcast, we go beyond the patient's injury to discuss how Chris used dynamometry to not just measure his patient's strength, but also on how to use it for training.
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Chris is a sports residency and performance trained physical therapist.
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After completing his physical therapy education and sports residency program, Chris received his master's of philosophy in biomechanics, specifically in the area of rate of force development from Auckland University of Technology.
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Chris has spent his career working in sports, sports performance, and military settings.
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Throughout his career, he has had a variety of teaching and lecturing positions, has presented at conferences and universities, and has a number of published peer-reviewed papers.
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In addition to currently working as a PT in the performing arts sector, Chris is the co-host of the PT InQuest podcast and co-creator of the continuing education course Dungeons& Dynamoms Chris has done a case study with Physio Network on this exact case where you could dive a lot deeper into this area than we were able to do in today's episode.
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You can click the link in the show notes to watch Chris's case study with a 7-day free trial.
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I think you're going to love this episode because you could just get a glimpse into how Chris's teachings can have a profound impact on your clinical reasoning.
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I'm Noah Mandel and this is Case Studies.
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All right, Chris, welcome to the podcast.
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Today, we're going to talk all about force testing and dynamometers.
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And Chris, recently you created a case study with us where you used a very interesting patient that you worked with as a vehicle to introduce us to this wonderful world of force testing.
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So before we actually dive into those concepts, can you give us a quick background on the patient's case?
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So I actually work down in Miami and in Orlando, so South Florida area.
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And I do some work in and around circus, Cirque du Soleil, not with Cirque du Soleil, but performers in and around that type of performing arts.
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So aerialists and teeter board artists, as you can imagine.
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wild, wild requisites and needs as it relates to athleticism, general sports qualities, strength, even though it's a lot of body weight, but we're talking accelerations.
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I mean, flipping, turning, jumping.
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It's fantastically terrifying if I'm being totally honest, because I don't like being inverted.
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So to watch some of this is fascinating.
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So I ended up working with an athlete that we help out with in this group.
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She's an aerialist and does most of her performances on silks.
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These are kind of lyric-type silk straps that hang that can be used to perform a variety of maneuvers, climbing, sliding, flips, turns.
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It's really quite impressive.
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But they are intended to let you slide up and down them.
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And so if you're kind of not locked into that, well...
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Gravity will win and it will pull you down.
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So she essentially slipped and then caught herself with one hand on the wrap.
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And so it created essentially an arresting, like her momentum is pulling her down, this sudden arresting stop where she caught herself.
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So imagine falling and catching a bar and she ended up with a lat subscap injury, essentially a proximal subscap lat injury, which I had seen twice before on the military side.
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And then on the baseball side, I've worked in a variety of contexts before this.
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So I had seen these before.
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Both prior were non-op.
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This was non-op as well.
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She got imaged.
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The surgeon said the same thing.
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There's not a ton of migration.
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They called it a grade two.
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As far as most recommendations clinically, they're going to push that towards a conservative management option unless the athlete feels as though they would like to pursue surgical intervention.
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Or they are in certain characteristics of bruising, tissue migration, that they feel like the outcome would be better.
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But almost all type two or grade two subscap lat injuries can be managed conservatively as they'll just kind of scar down.
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And their force production qualities end up remaining fairly good.
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So she decided to go forward with that and come see us on PT.
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So I saw her a few days after that, which is the reason that this case is interesting because I got her within a week after All of this.
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So yeah, still bruised.
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I mean, you can imagine even active range of motion at that point was fairly limited to get her to in range flexion.
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She didn't love that, right?
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Cross body AD reaching across was like, yeah, that's still super tender.
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And the physician that we work with has worked with us before and has seen some of this stuff.
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So they were very intrigued of like, yeah, go here, go see them, you know, within the next week.
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They'll talk to you about how we're going to kind of work on graded exposure and specific tissue adaptation using this cool little toy.
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This person's already bought into it.
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So she shows up and then we kind of go forward on that.
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So super interesting.
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You've
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worked with a lot of people throughout your career.
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And the fact that you've only seen this injury a few times, people may be listening and think like, okay, so how is this relevant to me?
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And it's not necessarily about this specific injury.
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It's a very interesting case.
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But again, we're using it as this vehicle to understand what force testing is.
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So what is force testing?
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And why would you use it compared to something like a manual muscle test?
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Yeah, force testing and should be probably, if we're being technologically, our nomenclature, terminologically pedantic about this, it would be strength testing, right?
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Because strength is the manifestation of how we do anything and demonstrate what our force qualities are.
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So strength testing in this way is objectifying beyond what MMTs could ever possibly do.
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I'm not an MMT hater.
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Let me be very clear.
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But I think manual muscle testing probably has equity and value in three domains.
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It's either painful or not.
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You could just dichotomously say, well, Noah, did that hurt or did that not?
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Okay, I'm on board.
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After that, you could probably grade it three ways.
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It could be a zero where I cannot move my arm against gravity if we're using, let's say, your elbow flexion.
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I cannot bend my elbow against gravity.
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Okay.
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I can bend my elbow against gravity, but that's all.
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I can't take any external resistance or I can take some external resistance.
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Outside of those three categories, there's no way to grade my input.
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And in most cases, MMTs are rate limited strictly by the practitioner, not the client, right?
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So it's a test of how hard I can push your elbow at that point, right?
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So Objectifying gives us a much more nuanced and much more objective expression of how much strength you have by measuring your force production quality using a dynamometer.
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It's a dynamometer that has a little load cell that's shaped like an S.
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When you pull it apart, there's electricity that goes through it, and that electricity is measured, basically how fast or how slow it goes through the cell.
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That is interpreted as force.
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Ever wished
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With Case Studies by PhysioNetwork, now you can.
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Watch presentations where top clinicians break down real-life patient cases, step-by-step, showing how they assess and treat even the trickiest conditions.
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It's the best way to improve your clinical reasoning and build confidence in the clinic.
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It's very cool.
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And the one that you use in this case is a Tindec, which connects to your phone.
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So you have this app that shows the patient and yourself how much force is being produced in whatever movement you decide to test, which brings us to the next question.
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What did you decide to test with this person?
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And do you just care about the overall number?
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Do you care about how long they can pull for?
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What are you looking for?
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Yeah, this gets into the nuances of strength, right?
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Like what strength do we care about?
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And I would argue that there's probably three different domains of what we care about.
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There's something that the client cares about.
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That strength is typically the end stage or some task-oriented strength.
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I want to be able to do a pull-up, a push-up.
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I want to squat a certain number.
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I want to be able to run or jump.
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Those have quite a bit of air and they're a bit more messy.
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But we on the PT side, on the rehab side, typically reverse engineer that into a needs analysis of, oh, well, here's some components of that end stage task.
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These requisites have strength characteristics of, well, if you want to do a pull-up, then you need to be able to do a pull-down at a certain amount and make a certain requisite amount of shoulder extension, elbow flexion, coordinated effort so that you can get there.
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So the concept is we reverse engineer this.
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This client is an aerialist.
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So you can probably imagine one of the hallmark tasks was, well, Chris, I need to be able to do a single arm pull-up on a silk strap.
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Like, oh, yeah, okay.
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Well, that makes sense.
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So then...
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I can take this load cell, which is what I did, which was the most powerful thing that we did in this entire case.
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I hung it from a rack, like imagine a rig with a pull-up bar.
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I hung that cell.
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I'd had her sit on the floor with her legs straight out in front of her.
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I let the cell hang down into a strap that was roughly the width of a pull-up bar and put her at in-range shoulder flexion and then had her pull down like as if she was going to do a pull-up into the load cell.
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Now, again, I can speak to the case more specifically.
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We did this at graded efforts, but the ultimate goal was to be able to make a hundred percent of her body weight and a pull down because then it meant, well, then she could theoretically, it doesn't, it's not a one-to-one, but theoretically do a pull up and pull her body weight up.
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If she could make a hundred percent of her, we know what she weighs.
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You got to be able to pick your body weight up.
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So she's like, oh, This makes total sense to me because I changed the 10-deck to give me load output in pounds.
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So she could see that's 50 pounds, that's 60 pounds.
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She knows what she weighed.
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I told her, we need to be able to get to your body weight.
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It's fairly intuitive.
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And if I can gamify that, which I did using the 10-deck, using the training software, we literally saw her force output climb up and up and up and up and closer to her goal of 100% of her body weight over time.
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Yeah, over, it took us about five months, which is what I anticipated.
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This is a substantial tendon and we're trying to get to a substantial strength output, force output, right?
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So we had milestones.
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She's like, well, when can I do a pull-up?
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I'm like, well, if we make an assumption that each arm pulls 50%, well then when you can make 50% of your body weight and I did it at full flexion at roughly 140 and then at about 90 because those are the, the three kind of key points to a pull-up.
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And so watching her, like, oh yeah, there was never a question of, hey, when can I do a pull-up?
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Like, you can do a pull-up when you can do this.
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It makes a lot of sense.
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Yeah, it's quite simple, right?
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And then we obviously use that for graded exposure.
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I'm sure we'll talk a little bit about that.
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But as, you know, I could use that process to anchor, retest, re-anchor, test, re-anchor, test, re-anchor the entire time to get her to that
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point.
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Which she loved.
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So speaking of that graded exposure, and you mentioned a word there, gamification.
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This is a concept that you introduced to me through this case study and also just through your teachings in general.
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And that's not just using the TINDEC or whatever dynamometer you're using for measuring things, but actually for training.
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And it's such a cool concept.
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It's really, really interesting.
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And you do such a great job in the case study of showing how to do this.
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But could you give us just a brief overview of how you do it?
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how you would use one of these for training?
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Yeah, so the fundamental point I think is twofold when it comes to using objective data for training.
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In this case, you're getting real-time feedback, which is even greater, but you get two concepts.
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Number one, you're re-anchored every time you come in.
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We know that your 1RM or your maximal effort as defined by an RPE, an RIR, or even a one-rep test has a fair bit of error day-to-day-to-day.
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But every time I program somebody's strength block with back squats, I'm not telling them every day you go in, I need you to one RM back squat and then take 80%.
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And that's what you're going to train that day.
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That's illogical.
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because that is quite a bit of effort.
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That's why velocity-based training and these other tools come into play.
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This allows us to hack that system a little bit because it's a single joint max effort, which is nowhere near as fatiguing as doing a 1RM back squat, but it's re-anchored every day.
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So I hope that your 1RM is going up, but I'm programming 60, 70, 75% of that 1RM that is being updated every single time that you train.
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Right.
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Because you're re-anchored every time.
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Number two is it gives you this silly, silly little red brick.
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And if anybody's ever used a tin deck, I'm telling you, it's like this little red brick on the screen that you hold the line in and you will be amazed the number of people that are like, I love this so much.
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Like, it's genius.
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It's so simple.
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And all it takes is them to do this once.
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They're like, oh, yeah.
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I want to do this.
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Are we going to do that again today?
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Yep, sure are.
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Okay, cool.
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It's phenomenal.
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So that is the gamification kind of training benefit.
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I use it for three different distinct purposes, and it's anchored differently each purpose.
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So phase one or purpose one is analgesia, which is pain dampening.
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This is not anchored to an MVIC.
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It's anchored to an MVIC or an anchored MVIC to pain.
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So I would have you come in, which I did for her the first week is, we didn't even test this position, but down the road, we tested before we even started doing a pull down, how much force can she make before she achieves kind of a one or a two out of 10?
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It's kind of this arbitrary pull until you feel like, yeah, I can feel that.
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So then that's her max force anchored to her symptom.
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Then I'm programming 70 to 80% of that number.
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So we are sub-threshold.
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And then we're anchored to a point that we can build her time under tension.
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I talk about this in the case study using TUT.
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Time under tension with isometrics is a really great way to start dose prescriptions.
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You can use TRIP as well.
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TRIP is the training impulse, which is TUT times some kind of internal load or theoretically external load if you want to anchor it that way.
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But it is time under tension times the intensity.
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In my case, I talk about bananas.
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I won't spoil that unless you want to talk about it, but Go watch the case.
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I think it's pretty entertaining.
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I use bananas all the time in clients.
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This client will still tell you that she remembers how many bananas that we would do each week.
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And that is her training impulse number.
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She loved this concept.
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So yeah, we start with analgesic exposures, NVIC to pain.
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And then phase two, we get into NVICs, which are hopefully non-regulated by symptoms because it doesn't hurt anymore.
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But now we're using it for physiologic adaptation, which is 70, 80% of your NVICs or 30, 40, 50% taken to really extreme volumes.
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And then the last range is taking training, finding an anchored NVIC and then trying to get there very quickly.
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which is essentially a proxy of rate of force development, which is time to peak, which is kind of a weird, useful nuance to kind of hack that system of rapid force exposure or production.
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And so you can use that all the different percentages.
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And in these cases, again, because you're re-anchored and it's gamified, she knows where 70% is, just go to the brick.
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And it's constant feedback and re-anchored.
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So each session she comes in, we're chasing that Goldilocks zone of stress adaptation because it's re-evaluated.
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If it's a bad day, then it's lower.
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If it's a good day, then it's higher.
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But it's 70% of what you can do that day, either to symptoms, either to absolute load or either to rapidity of force.
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So it works out nice.
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Perfect.
00:17:37.787 --> 00:17:39.688
Chris, thank you for coming on.
00:17:39.728 --> 00:17:42.171
We just scratched the surface here.
00:17:42.191 --> 00:17:53.119
You dive into so much detail into your case study about why we use these things, how we use them for testing, how to use them for training.
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There's even screen recordings of the actual app and sort of what exactly you're talking about with that red brick and how to use it for training.
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You show us how to create charts and track this data over time.
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I really cannot recommend it.
00:18:06.832 --> 00:18:18.919
Chris, thank you again for coming on.
00:18:19.240 --> 00:18:19.681
My pleasure.
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Enjoy the presentation, everybody.