Mastering the Physics of Double-Unders

Alan Fredendall // #FitnessAthleteFriday // www.ptonice.com 

In today's episode of the PT on ICE Daily Show, Fitness Athlete division leader Alan Fredendall discusses the research, physics, clinical context, and patient input that goes into deciding if mechanics with lifting are "good" or "bad".

Take a listen to the episode or read the episode transcription below.

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EPISODE TRANSCRIPTION ALAN FREDENDALL All right. Good morning, folks. Welcome to the PT on ICE Daily Show. I hope your Friday morning is off to a great start. We're here a little bit early in the garage. We're going to be talking about some double unders today. Welcome to Fitness Athlete Friday. My name is Alan. I'm happy to be your host today. Currently have the pleasure of serving as our Chief Operating Officer here at the company, as well as the Division Leader in our Fitness Athlete Division. We love Fitness Athlete Friday. We would argue it's the best day of the week. On Fitness Athlete Friday, we talk all things relevant to the CrossFit athlete, Olympic weightlifting, powerlifting, bodybuilding, anybody that's recreationally active in the gym. We also talk about our endurance athletes, whether you're running, rowing, biking, swimming, triathletes, If you have a person that's getting after on a regular basis, Fitness Athlete Friday has a topic for you. Some courses coming your way from the Fitness Athlete Division. We have a couple live courses before the end of the year as we get ready to close out 2023. This weekend, as in tomorrow and Sunday, November 4th and 5th, both Mitch Babcock and Zach Long will be on the road teaching. Mitch will be down in San Antonio, Texas, and Zach will be in Hoover, Alabama. Even though it's last minute, both of those courses still have some seats. And then your final chance to catch Fitness Athlete Live will be the weekend of December 9th and 10th. That's gonna be out in Colorado Springs, Colorado, and that will be with Mitch as well. Online from the Fitness Athlete Division, our entry-level course, Clinical Management Fitness Athlete Level 1 Online, previously called Essential Foundations. The next cohort of that class begins November 6th. We love that class. That is a great entry-level experience into all of this stuff if you have not taken it yet. We take you through the very basics, back squats, front squats, deadlifts, presses. We get into some basic gymnastics with the pull-up and introduce you to Olympic weightlifting with the overhead squat. Along the way, we have case studies relevant to athletes with those particular issues that we discuss with those movements. We talk a lot about loading and we get you introduced to basic programming, both for injured athletes and also how to recognize CrossFit style programming, strength style programming to better prepare you for those folks who want to continue on to our level two online course, previously called Advanced Concepts, who really want to drill down into programming, advanced gymnastics, advanced Olympic weightlifting, and truly become the provider of choice for athletes in their region through the clinical management fitness athlete certification. So that's what's coming your way course-wise from us in the CMFA division. WHAT ARE WE DOING WITH THE DOUBLE UNDER? Today we're going to talk about double-unders. This is personally an issue I've struggled with for a long time and probably maybe aside from pull-ups and handstand push-ups, one of the more basic movements we see in the gym that still a lot of your membership base will struggle with, maybe you personally struggle with, and I want to talk about what are we actually trying to do with the Double Wonder, some tips and tricks and cues to think inside your mind as you're going through them. I want to spend some time talking about the equipment involved in jumping rope because I think there's two sides of the equation, people with very basic equipment and people with maybe equipment that they don't need that's maybe too expensive, too advanced, And then I also just want to talk about how to begin to better practice double unders so that you can work towards achieving them and being able to complete them during a workout, in large sets, when the CrossFit Open comes up, or just in your regular workouts at the gym. So first things first, with double-unders. When I ask a lot of athletes in the gym when I'm coaching, when they say, oh my gosh, I just did five double-unders in a row, I say, great, great, what were you thinking about? And overwhelmingly, the majority of the people say, I don't know. I couldn't tell you what I was thinking about. And that strikes me as very different from a lot of stuff that we do in the gym. People usually have maybe one cue or maybe even a couple cues in their mind when they're setting up for a heavy deadlift, when they're setting up for a clean and jerk or a snatch or a handstand pushup. They often don't kick up upside down or go to max out their snatch and tell you that they had nothing going on in your brain. But something about the double under, people think it's just magic, how you learn these and how you get better at them. And unfortunately, it's not magic. Fortunately, it's just physics. So I want to talk about really at a base level, at a nerdy physics mathematical level, what are we doing with the double under? We are translating linear force. We are creating force across the lever that then transforms into rotational force where your jump rope handle meets the bearing. FIX THE SET-UP If your jump rope is nice enough to have a bearing. So a lot of times the setup, even with just the handles is wrong of looking at a jump rope. Again, it's quite a basic piece of equipment. It's got some handles. you to hang on to in a rope. Even a cheap moderate jump rope of $20 should have some sort of bearing set up so that it spins a little bit. We are trying to create force at the end of the handle that as we flip that jump rope it turns into rotation through the rope and that by doing it both hands at a time with that flicking motion we spin the jump rope. What we're not trying to do is physically spin the rope ourselves with our shoulders, right? We're trying to create rotational force through a flick. So the first thing is making sure that you are even handling your jump rope appropriately. If you are cinched down with a full grip, right where the handles meet the bearing, first of all, you can physically block the bearing if you're not careful. If you hold right here with a depth grip, that bearing cannot spin anymore, right? It's going to be extraordinarily difficult to easily create rotational force here and you're going to naturally be that person who has to spin your arms to spin the jump rope. That's exhausting. It's not a great way to do single unders and it's an even worse way to do double unders. So first things first, where are you grabbing the handle? You should be grabbing further down the handle, ideally with a loose grip, as low on the handle as you can get, right? The longer the lever, the more force amplification we have, right? The more force is going to be transferred and transformed into rotation down here versus the higher we grab up towards that bearing. So a nice loose grip, thinking about flicking, creating linear force at the bottom of the handle that creates a spinning force for me up at the bearing. So that's number one of making sure that you're even using the jump rope correctly. The next thing is making sure it's sized correctly. I always laugh when I see people in the gym who I know are taller than me, which is not very useful because most human beings are taller than me, but I know someone is a couple inches taller than me and I see them using a rope shorter than a rope I would use and I think What the heck, why are they using such a short rope? It makes sense why trying to do double unders, they're bringing their knees up to their chest and bending their knee to try to clear the rope because the rope is so short. How do we sign the jump rope? We take the jump rope, we hold both handles, we step one foot, we try to even it out as much as possible, bring it towards our body, and the length of that rope should be at our nipple or maybe a little bit higher. If it's down at our stomach, it's too short. You're gonna have to do some really unnatural jumping things, like piking your hip, or kicking your legs back, or both, just to be able to clear that short rope. Likewise, being a little bit longer is okay, but this thing up to my chin or above my head, I have a lot of slack behind me now. I'm moving a lot of extra weight I don't need to, and that's all the more drag factor on the rope that's gonna mess up my timing as I try to learn double unders. So making sure we're holding the handles in the appropriate place and making sure that we understand how to measure our jump rope. A really nice jump rope will have maybe a nut or a screw here to adjust. This is a typical, what we call a class rope. This is just a $20 rope from Rogue. You'll often see these in the wall at a gym for everybody in class to use. These can't be adjusted. They go based on your height. There should be a table or a chart or the coach should know what color you should be using based on your height, assuming that you know what your own height is, to make sure that you're using a jump rope that is long enough with maybe a little bit of extra slack, but is not extraordinarily short or long. So that's first things first, using linear force to create rotational force, making sure the rope is sized to us correctly, and making sure we're holding the handles in the right spot so that we're not hampering ourselves from creating that rotational force. SOMETIMES IT'S THE WRENCH We have a saying, with jump rope, with most things in life, it's usually not the wrench, right? It's not the equipment, it's the mechanic. But sometimes it is the wrench. A lot of folks start trying double-unders with maybe the class rope they have, and I think that's a great place to start. Now the issue is a lot of folks will start trying double-unders, they'll look at people in the gym who are really great at double-unders, and not recognize that that person probably started with the class rope, and they'll immediately go out and buy a $200 competitive CrossFit game speed rope. There's a couple issues with the wrench itself of making sure you have the right wrench. We've already talked about length. A really nice jump rope, again, will have a way to adjust the length that you can undo a screw or a nut and make it longer or shorter and get it really dialed in. These ropes, again, are a fixed length but making sure the length is exactly correct. The next thing that most people don't consider is that this jump rope has some weight. Yes, the handles have weight, but that's going to be relatively fixed based on the brand that you have. So not considering the weight of the handles, what is the weight of this rope? This is a class rope. This is about 2.5 ounces or so, which I would call a medium weight rope. When we are doing jump rope, In learning double-unders, the best thing you can do is use a rope that's a little bit heavier.

null: Why? Two reasons.

SPEAKER_01: When you spin a heavier rope, you can hear it slapping on the ground in the gym, even over the loud music. That helps your brain learn the timing. A heavier rope also forces you to develop wrist speed. When we're doing double-unders, it's not about how fast you jump, it's about wrists. And a really light rope doesn't force you to learn that speed because it costs you almost no energy to go through that movement pattern. So for a lot of folks, they're trying to purchase the most lightweight rope ever, and I'm going to show you some different ropes here in a second, when in reality they should probably be working with a heavier rope. Again, this is a class rope. This is maybe two and a half to three and a half ounces, somewhere in the middle. What's going to help a lot of folks Smartgear brand rope. You can buy this from Rogue or from RX Smartgear directly. You can see just by looking at these two ropes, significantly thicker, right? This is a 4.1 ounce rope. The handles are different. Yes, they spin a little bit better. They have a little bit better hand grips. You can see here different spots to put your thumb along the handle. But most importantly, the cable is heavier. This is going to teach hand speed, this is going to build up endurance with the double under, and it's also both the sound and the feeling of this rope is going to help learn timing a lot better for our jump rope. So making sure that we have the right rope. Again, almost everyone trying to get good at double unders immediately goes and buys the $200 speed rope, when in reality they should probably buy this. Now the nice thing about these ropes, as you can see, I'll bring it up really close, is this is just a keychain type carabiner. When I'm ready for a lighter rope, the most expensive part of a jump rope are the handles. The cable is usually cheap or sometimes even free if it gets frayed. If you fray your actual rope, you can email Rogue, you can email RxSmart here, they'll send you a new cable that you can reattach to your handles and you can use the same handles forever. So as you get better, you can detach, put a lighter cable on, make it easier and more energy efficient as you actually start to string together double-unders. But early on, you're going to want a heavier rope, something around four ounces. That's the biggest recommendation I can make to folks who are trying to learn double-unders, and especially to those folks who have 19 different speed ropes at home. They've got a second mortgage on their house full of jump ropes just to pay for them all. and they're going lighter, lighter, lighter, thinking they need a lighter rope, a faster rope, lighter handles, diamond grip handles, when in reality they just need a heavier cable. So when in doubt, go heavier. Again, four ounce rope compared to maybe a two and a half or three ounce rope. Once you can start to turn over bigger sets of double unders, 25, 30, 50, you're able to start doing them in workouts, your efficiency, your endurance with them improves, now you're ready for a cable itself is basically non-existent. This is aircraft grade aluminum. This is about eight tenths of an ounce. So almost 500% lighter than that heavy rope I just showed you. This weighs almost nothing. It is very hard to feel when you jump rope with this cable and it's very hard to hear as well, especially if you're in a CrossFit style gym in the middle of workout with loud music playing. What's different about this besides the cable weight? The handles are so much nicer. They are diamond grip. My thumbs can lock on. I can hold very low on the rope. Again, I want to have as much time for that force to build up and transfer along the length of the handle as I can. I can hold just my index finger and my thumb and really develop that flicking motion. What's also very nice is look at the spin on this handle. right? That thing spins forever. Very, very, very efficient for large sets of double-unders, but only once you can actually do them. So this is kind of the in-stage progression of somebody who looks at a workout that has a couple rounds of 30 or 50 or maybe even 100 double-unders and says, no problem, I got These ropes are about $200. And again, the most expensive part arguably is the handle. If the cable frays, you can replace it. But a very, very, very high quality jump rope intended for folks who have already learned how to do big sets of double unders, ideally using a heavier, cheaper rope. So that is what we would call a speed rope. So that's the wrench. BUT IT'S USUALLY THE MECHANIC Now let's talk about the mechanics. because there are a lot of things we can do, a lot of cues we can give that can very quickly make double unders a lot better. The first thing is understanding, again, in a double under, what changes is my hand speed. Jump, spin, spin, jump, spin, spin. It is a double spin of the rope. It is not an increase in my jump rate. A lot of folks, off the ball of their foot. Because in a single-under, we're only clearing the rope once, we can get away with a very small jump and just clear that rope once. We see a lot of boxers do this. You see a lot of people in the gym who have jumped rope a lot in the past do this with single-unders. They can crank out 150 single-unders in one minute with that very fast, low jump. That's not gonna cut it for a double-under. Why? The rope has to pass twice. A lot of athletes in the gym will ask me, I have no problem getting it over the first time, but it gets caught the second time. The answer is yes. The rope has to come back around again twice and you have to be in the air the whole time. That's why it's called a double under. You're trapping the rope on the second time through, which is why you're not getting your double under. How and why are we trapping the rope? Most commonly, is we do not increase our jump height, we just now try to jump even faster. All we're gonna do there is trap the second pass of the rope that much more quickly. We're just getting more efficient at bad double-unders. We need to consider a smaller, taller, slower jump. We should practice single-unders on the ball of our foot, and we should practice a little bit taller jump, but not try to pick up our legs not jump speed. If you correspondingly increase your jump speed, you're going to trip because you're now trying to basically get in rhythm and jump twice for two rope swings. That doesn't make sense. Keep your jump speed the same. Stay tall, vertical on the ball of your foot, and jump a little bit higher. Practice single-unders that way. When you can begin to turn over 50 or 100 single-unders like that, now you know you have the jump height, the jump speed, to be able to begin to turn over double unders. Remember, wrist speed, not jump speed, and stay on the ball of your foot. A lot of folks will do some really dramatic stuff to get that rope over twice, and they will land on their heel. Again, the rope has to pass twice. If you land on your heel, there is no physical way that rope can pass under your foot for its second time through. You're going to track the rope underneath your foot. So small, short, sorry, tall, vertical jump. PRACTICING & DRILLING DOUBLE-UNDERS Make sure we're practicing wrist speed. A penguin drill is a great drill to give people, to have them practice maybe what's a new jump height and cadence for them. And at the top of their jump, have them slap their thighs twice to imitate the double flick of the jump rope. You'll find a lot of athletes who think they should be able to do double-unders, struggle a lot with that drill. They're used to that short, very fast jump cadence for single-unders. Asking them to slow down and jump a little bit higher wrecks them. It also messes them up mentally when now they have to focus on actually doing something with their hands. You'll find they're probably not as ready for double-unders as they thought they were. So double-unders, not magic, just physics. We are creating force across a lever, the handle of the jump rope. We're holding it as low as possible. We're trying to create rotational force where the rope meets the handle at the bearing. We're holding it as low with as loose of a grip as we can. We're thinking about flicking the wrist, not spinning the shoulders. Sometimes it is the wrench. Make sure the rope is the correct length. Make sure newer athletes who are beginning to experiment with double unders use a heavier rope, something three, four, maybe five ounces, and that we reserve those speed ropes for once we're actually able to string together bigger sets of double unders with a heavier rope. PROGRESSIVELY OVERLOADING DOUBLE UNDERS The final thing is how to progress these. A lot of folks want to be able to do more unbroken sets, Can you just practice more sets of double unders? Yes. The key thing though is that we practice that. We don't try to do it in the middle of the workout under an extreme amount of cardiovascular fatigue and that we consider double unders no different than a back squat or a clean and jerk or a deadlift. That we take principles of progressive overload and we carry it over to our body weight, cardiovascular stuff, especially higher scale, like double unders. How do we do that? Things like a Zeus Rope. or a drag rope are great. A drag rope is literally climbing rope with handles. It has, you can see the same handles as some of the other jump ropes I've shown you. The only difference now, there is no handle spin. The only way I'm going to rotate this rope is by being really aggressive and really fast with my hands. This is a nine ounce, I guess you'd call it cable. Again, it's technically just a length of climbing rope. This is nine ounces. So this is 900% heavier than the speed rope. So if I want to get better at double unders where I can look at a workout that has a couple rounds of maybe a hundred double unders and it has some other stuff in there too that's also going to make me tired from a cardiovascular perspective, how do I know when that workout shows up that I can blast through those with my speed rope? Well, when I go back and take class workouts that maybe have small sets of double unders 20 or 30 at a time, I bring my drag rope to class. And I do smaller sets with a heavier, slower rope that continues to progressively overload my double-unders so that when big sets do show up in different workouts, I can handle those no problem with my speed rope. So it takes practice, intentional practice. Folks are always disappointed that they don't magically learn double-unders 18 minutes into a 20-minute AMRAP. That's not how it works. Sometimes it does, but it usually doesn't. Practicing this stuff at home with a cheap jump rope from Rogue that's 20 bucks, practicing 10 minutes a couple times a week is really going to go a long way. I always tell folks when they're practicing double-unders the same way I tell them when they're practicing things like pull-ups. When you're learning to kip, when you're learning that motion, forget about getting your head over the bar. Just learn the rhythm. That's the most important thing you can do. I say the same thing to folks who are going to be going home and practicing double-unders. Don't focus on actually getting the double under. Focus on doing the mechanics correctly. Use a timer so that you're not just in your garage for an hour and you're breaking stuff because you're so frustrated or the neighbors are worried because you threw your jump rope into the street. Set a timer, do as many as you can, and then take a break for two minutes and do a couple sets of that. Make sure that you aren't treating it as a workout, but that you're treating it as practice and that you use different methods once you actually can do double unders. to continue to progressively overload your double unders. So double unders, not magic, physics, make sure your wrench is set up, but make sure your mechanics are dialed in as well. And make sure if you want to get better at these, that you actually spend diligent time to practice and make sure that it's actually practiced and it doesn't turn into a second workout that day. I hope this was helpful. I hope you have a fantastic Friday. If you're going to be at a live course this weekend, we have 10 of them going on, I believe. So I hope you have a fantastic weekend. We'll see you all next time. Bye everybody.

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