0:04 I'm not going to go far into this but I hope that I turn a couple of you 0:09 at least into as big as nerds as I am. You think I'm kidding, I'm not. I 0:14 have a Sheldon bobblehead on my on my bookcase in my office, that's 0:19 what my friends call me is Sheldon, I'm like, "That's great, I hope I'm a little 0:23 bit more personable." Anyway I hope I turn you into a couple nerds and 0:28 after you take your kinesiology course and you passed your final, because I want 0:31 you to pass your tests, you will look into some of this stuff, the 0:36 nervous system, you literally could spend a lifetime studying a single aspect of 0:40 the nervous system. Central nervous system is what? Brain and spinal cord. 0:48 What is the function of your central nervous system? This is the thinking or 0:57 the control center, even your spinal cord. Your spinal cord does a fair amount of 1:03 "thinking." Here's an interesting experiment that I never want you to do. 1:11 If you touch a hot stove, you ever done this? Everybody's done this, 1:18 touched a really really hot object, you will pull your arm away before you have 1:25 the conscious thought that it was painful. Fact. Part of that has to do with 1:32 the fact that your pain pathway is slower than your muscular pathway. Part 1:41 of that also happens because this is a withdrawal reflex and a reflex happens at 1:46 the spinal cord level. Crazy huh? You touch something hot, your spinal cord 1:52 doesn't even get the signal up here, goes "pink," then you go "ow." You don't go "owwww." 2:02 That doesn't, it doesn't happen that way. Your peripheral nervous system 2:07 is just the pathways in and out, that's it. That makes sense? So your peripheral 2:15 nervous system is what we know of as nerves. 2:17 You have you afferent and efferent nerves, you have your sciatic nerve, 2:23 what's your sciatic nerve? Yeah, it goes down your leg, it's a group of axons. 2:30 Axons go to neurons, but those axons are part of your your peripheral 2:35 nervous system. Afferent means what? Goes in yeah, efferent exits. Good call. 2:48 Efferent, E, exits. Efferent go to muscles for the most, as far as we're 2:53 concerned for now, they also go to organs and stuff Afferent is sensory 2:58 receptors. Everything from our eyes which we know as a sense, to touch, to even 3:06 little receptors inside of joints that tell us how much pressure is within that 3:10 joint, what position it's in. You might have heard of muscle spindles 3:14 and Golgi tendon organ, that's all afferent information. So neural control 3:24 of human movement, receive information. When you think of motion, you could 3:27 break it down to receive information from sensory afferents, interpret 3:31 organize and plan, and then activate motor units via of the motor nerve. So 3:39 you have to sense your environment and then react to it, your body is 3:43 continuously doing that. The complexity of that is staggering. The fact that we 3:48 move at all sometimes is just staggering to me, all of this stuff working together, 3:53 and how if you mess any of that up at all, that all changes. So what is a motor 4:02 unit? Anybody? Let me take a step back, how much you think I can 4:09 curl. Be generous. 4:14 30s? That's not generous, I'm 6 foot 3, 225 pounds. 70s? Now you're being too generous 4:23 but thank you, that's at least a little closer. I think with 70s with bad form, I 4:28 could swing some 70s up. Yeah. Do you even lift?! You know who I'm 4:37 talking about? You ever watch Bro Science Life? You have to watch this guy, 4:41 This guy is hilarious, he's created a character around the worst gym bro that 4:51 you can possibly think of. He is on a whole other level hilarious. He has a 4:58 whole video on how to get out of leg day, you get what I'm saying? 5:02 That's who this guy is, he'll go over the squat rack and start doing 5:07 curls with the barbell. It's awesome. Anyway, so maybe I 5:13 could cheat curl 70, let's say I could curl 60s, 50s probably with good form, 5:18 so then the question becomes when a muscle fiber fires it fires completely. 5:26 There's no dimmer switch on a muscle fiber. You kind of know this. 5:31 You hit the the threshold, the activation threshold, create an action 5:36 potential, the muscle fiber fires, it contracts. It doesn't go "little 5:42 contraction," it just contracts. So then the question becomes if I can curl 60s, I 5:49 can generate that much force, how do I curl this marker without throwing it 5:54 through the ceiling? You get the the problem here? If I put 60, lifting 60 6:04 pounds worth of force under this marker, what would happen? 6:12 Yeah so that's a problem. How do I control that? How many fibers I recruit. 6:21 Now how my body organizes that is through something called a motor unit. So 6:29 you're exactly right, the only thing is is we don't have a nerve going to every 6:34 fiber. That actually doesn't make sense. What your body's done is it's, you see 6:39 how this is worked out? This is a nerve and I'm going to attach that to four 6:46 fibers, so when that nerve fires, all four of those fibers 6:53 will fire. And I might have bigger motor units than that, that have 100 6:56 fibers, 120 fibers, my curling 60 fibers, and I may have a couple fibers there are 7:05 only one, for really finite movement. Does that make sense? So based on how many motor 7:11 units I recruit and what type of motor units I recruit will be dependent on what 7:17 type of force I apply. Just remember, as soon as that motor unit fires, it does 7:22 what? Fires completely, it contracts as hard as it can. That's it, on off. You'll 7:32 find that a lot of things in the body are on/off, yes/no, facilitate/inhibit, 7:40 works a little like a computer, right? 0 1. 7:47 Neuromuscular efficiency. This is a little foreshadowing. I know this 7:52 morning I'm doing a lot of foreshadowing, giving you a little bit of why you 7:55 need to keep up with this. This is the definition of neuromuscular efficiency: 7:59 the ability of the neuromuscular system to allow agonists, antagonists, stabilizers 8:05 and neutralizers -which if you haven't learned that yet you will tomorrow or 8:08 you will later in your class, those are the different roles a muscle 8:12 can play - to work synergistically to produce, reduce and dynamically stabilize 8:17 the entire kinetic chain in all three planes. 8:22 You got part of that definition down already, you know the all three 8:26 planes part. Now we just got to fill in the rest. All right so there's a little 8:34 workbook page in there called "Putting It All Together. I think the workbook page 8:39 is actually even nicer than that is, in the essence that you have a word 8:44 bank in the bottom. I want you to take a couple minutes and fill that in. 8:49 Alright so the blank receives information from the environment, 8:55 organizes that information and initiates a motor program. The nervous 9:00 system. Movement occurs when a muscle contracts, the muscles pull on? Yes 9:06 tendons. Everybody always goes bones, and I'm like um. The tendons, in turn, pull on 9:13 bones, the bones move as dictated by the joint type and structure, joints are 9:19 supported by ligaments which connect bone to bone. Now if you're going to get 9:23 really nerdy, part of this is putting in your reps. You know what I'm talking 9:29 about? You put in your reps at the gym right, how many you guys go to the gym, 9:32 regular basis, good, good. Good everybody should go to the gym, we need to be 9:38 healthy. You got to put your reps in at the gym, you got to do your work. 9:42 Part of knowing this stuff is doing your reps as well. So one thing you can 9:48 start doing to yourself is imagine if you just thought about that for one 9:53 joint motion. Let's say I did a curl, what muscles will do elbow 10:01 flexion? What if, if we wanted to take it one further which I know is not for this 10:08 class, what nerve innervates those muscles? Oh oh right what are the tendons? 10:17 Tendons are going to be named after the muscles that's not too hard but at least 10:20 be able to visualize what those tendons look like. What joint does it cross? Let's 10:25 just pick one, we said elbow, what are the names of all the ligaments that 10:30 cross the elbow? You get what I'm saying? 10:36 Imagine if you did that and you just took one joint a day, 10:44 one joint action a day. How long would that take you? 20 minutes maybe, you got 10:51 Google, you got Google and my website, you have it easier than 10:57 the previous generation who would have to go to the library look this stuff up in 11:00 several text books. Imagine if you did that with one joint, just sat 11:05 down wrote it out, you tried as much as you could by memory right, and then 11:10 you found the rest on Google and wrote it down. The next day you tested yourself 11:14 on that joint to make sure you remembered it, and did one new joint. How 11:18 long would that take? 20 minutes a day. How good would you be at your anatomy at 11:24 the end of one year? You'd be crushing. You would look at any 11:29 kinesiology class and go I got this, it wouldn't even be a problem. 11:35 Makes sense right, now let's just take one thing through this.
