 Hey everybody, Lance Coyke here. I wanna discuss the, you know, previously we talked about long, slow duration activities, those, you know, repetitive constant movements. I wanna kind of take that back and take a piece of that and talk a little bit about the difference between rhythmic activity and like a constant under tension activity. So our two examples here is gonna be running as a rhythmic activity and then just like a squat hold as a constant tension activity. So let's describe some of what's happening here. With a rhythmic activity, I have this cyclical nature of everything. So I get a contraction and then a period of rest, a period of rest. And then I get another contraction and then a period of rest. And then another contraction, a period of rest. And it happens over and over and over like that. And if, you know, if I'm running a marathon, it might take three, four hours, right? I might be doing that for a really long time. Now the physiological demands of that are, you know, I have an energy demand. I need to be able to repeat repetitively push ATP or create ATP around the muscle tissue and get that, you know, get everything contracting over and over and over again. And, you know, as I do a really, really long bout of exercise, I'm gonna need to make sure that I can keep finding energy because my muscle stores, my muscle glycogen and my liver glycogen, it's gonna run out. And then I'm gonna start to have to tap into my blood glucose and I'm gonna have to start mobilizing that glucose from other places. But it's just, it's a lot slower to get it from fat through lipolysis than it is from, you know, just cleaving off a glucose six phosphate molecule from glycogen and putting it in the bloodstream so that it's ready to use. So we're talking about this rhythmic thing. So if I have a really, really long bout of exercise, I might need some intra-workout nutrition, right? But for the most part with the rhythmic stuff, it's easier to sustain. If I go really, really fast, what happens is I still have this rhythmic contraction, but the breaks are shorter and shorter and the contraction becomes a longer proportion or a larger proportion of the entire exercise. So I have less time to rest. I have more demand for muscle contraction, therefore. My work output's gonna go up and that's something to measure. I, you know, I wanna see that my performance is increasing but I have to be cognizant of whether I can support that activity for long periods of time. Now, if we, you know, take all that away, stop talking about the running, the LSD, the marathon stuff, let's start talking about a squat hold. So to think about it from like the most extreme example, what if you put, you know, 70% of your one RM on a bar and squatted down and held it? You would gas out really quickly, right? You would not be able to maintain that for very long. And the same is true if it's a body weight variation. Like you can do repetitive body weight squats for much longer, you know, depending on how far you're going, for much longer than you can hold at that lowest point of the squat, depending on how you're holding. Like if you're holding yourself up with your muscle, that statement is true. If you're holding yourself up with your back when you hold it and then you're actually using your muscle when you go, well, then you might fatigue more when you're using your muscle, right? It's more active, it's more energy intensive. The point here though is that people don't, people, if you're holding this contraction, you don't have time for recovery. So I'm going to fatigue faster. So I have to look at my training that way. If I'm going really slowly, I have to think, well, I don't really have, even though I'm moving slower and I don't need quite as much force because I don't have to move quite as fast, even though that is true, I'm not getting any element of rest. So my muscle physiology has to have some sort of option to clear out the byproducts of creating that energy. And we've already talked about some of these energy systems, this lactic anaerobic energy system is highly correlated with fatigue. And as that lactate builds up, we have hydrogen ion build up and the muscle just stops working quite as well. And at a certain point, it actually stops working because the pH is just too low, too acidic. That's just some food for thought on the differences between a rhythmic activity and a contraction hold a amount of tension activity.