Kipping Pull-Ups: How They Differ From Strict Pull-Ups, Why CrossFit Uses Them, and Whether the Reps Count (2026)
A kipping pull-up is a pull-up where you hang from the bar, swing your body back and forth, and redirect that momentum upward to get your chin over the bar. In CrossFit it's the default pull-up for timed workouts, and while the strict pull-up, done without that momentum, uses the same bar, the two are used for different purposes.
This post walks through what the kip is and why CrossFit uses it, what research measured about the difference between the two movements, and how official tests and PULL UP KING count reps done with momentum.
What is a kipping pull-up? Arch, hollow, and the swing between them
CrossFit's guide to the kipping pull-up describes it like this. You start hanging from the bar with your arms fully extended, then build momentum by moving between an "arch" position, where your chest moves forward and your feet go behind your body, and a "hollow" position, where your chest moves back and your legs come forward. That swing is called the "kip," and power from your hips and arms working together pulls your chin over the bar. The same guide introduces the kipping pull-up as a movement common in gymnastics, and says CrossFit added it to a strength and conditioning program for the general population in the early 2000s.
Research draws the same picture. Dinunzio et al. (2019) describe the kipping pull-up as a standard pull-up with a gymnastics glide kip added, and Williamson and Price (2021) treat kipping and butterfly pull-ups as variations of the strict pull-up in which you gain momentum through hollow and arched body positions before accelerating upward. In this post, "strict pull-up" means a pull-up done without that momentum.
How far your body moves differs, too. In the Dinunzio study, 11 athletes did 5 standard pull-ups and 5 kipping pull-ups, and in the kipping version, maximum hip angle was on average 48.8 degrees greater and maximum knee angle 56.5 degrees greater.
Why CrossFit uses kipping pull-ups: workouts against the clock
CrossFit's guide says the movement is prioritized in workouts scored "for time" (by how long you take) or "for reps/rounds" (by how many reps or rounds you complete), when you want to get through the workout as quickly and efficiently as possible. In those workouts, the kipping pull-up is assumed to be the default pull-up unless stated otherwise. The example it gives, "Fran," is 21-15-9 reps of thrusters and kipping pull-ups.
As CrossFit explains it, a properly executed kipping pull-up, compared with a strict one, increases power output, lets you complete more reps, raises cardiovascular output, and builds the skill needed for maximum efficiency. The reasoning is that your hips generate upward momentum and pass that power on to your upper body to get your chin above the bar, which minimizes fatigue and lets your whole body get more work done.
The guide is also clear about the purpose. It says the kipping pull-up isn't typically used to build maximum upper-body strength or muscle size; its goal is to increase endurance and stamina. To the criticism that it "isn't a strict movement" or "isn't a real pull-up," it answers that this misunderstands how the movement is applied, while noting that CrossFit still does strict pull-ups and recommends them as a prerequisite for the kipping pull-up. So whether kipping is right or wrong has less to do with the movement itself than with what you're trying to measure.
How CrossFit teaches the kip
The progression CrossFit says it teaches at its Level 1 Certificate Course starts with the kip swing. You learn to swing between arch and hollow from your shoulders with straight arms. Next, at the back of the swing, you press down hard on the bar with straight arms to create upward momentum. Then you add a pull with your arms at the highest point of that kip, and finally you link several reps together. If you've reached the step where you pull with your arms and still can't do a strict pull-up, the guide recommends doing the remaining steps with your feet on a box. The common mistakes it lists are starting the swing with your legs (it should start at the shoulders), pulling with your arms before you have upward momentum, and dropping from the top without control, so that you have to swing again before the next rep.
Kipping pull-up vs strict pull-up: two EMG studies
How the muscles work differently in the two movements has been studied with electromyography (EMG), which measures a muscle's electrical signal through electrodes on the skin. The two studies below point the same way: with momentum, signals from the lower body and trunk went up, and some upper-body signals went down.
Dinunzio et al. (2019) found that during kipping pull-ups, signals from the rectus abdominis, external oblique, iliopsoas, and tensor fasciae latae were higher than in standard pull-ups, while the biceps signal was lower. The authors wrote that, depending on your goal, you might choose the standard pull-up for more upper-body muscle activation, or the kipping pull-up for more full-body activation with the potential to do more reps through reduced upper-body fatigue. Since the athletes only did 5 of each, though, the study didn't directly measure how many reps anyone could do.
Williamson and Price (2021) recorded EMG from three upper-body and three lower-body muscles in 11 people doing strict, kipping, and butterfly pull-ups, and compared the kipping and butterfly values against the strict pull-up as the baseline. They looked at the way up and the way down separately.
- The lat signal was lower than in the strict pull-up on the way up in the kipping pull-up, and on the way down in the butterfly pull-up.
- The biceps signal was lower on both the way up and the way down in the butterfly pull-up.
- Signals from the rectus femoris, gluteus maximus, and rectus abdominis were higher in both kipping and butterfly pull-ups, but the results differed between phases.
The authors concluded that both styles of kipping increase lower-body muscle activation and decrease upper-body activation, and that because the kip is generated differently, the two movements show different muscle activation in each phase.
Both studies measured signals during a single bout of the movement, so they say nothing about how your body changes after training one way or the other. Which muscles work in each phase of a strict rep is covered separately in the pull-up muscles post.
Do kipping reps count? It depends on the test
Kipping is the default in some places, but the three official tests checked for this post all disallow momentum.
- U.S. Marine Corps Physical Fitness Test (PFT): Marine Corps Order 6100.13A says the intent is a vertical "dead hang" pull-up. A certain amount of body movement will happen as you pull, but the intent is to avoid a pendulum-like motion that helps you complete the rep. Whipping, kicking, or kipping of the body or legs, or any leg movement used to help you up, isn't authorized, and if it's observed, that rep doesn't count for score. The starting position is arms fully extended with the body motionless. You can step up or jump up to reach the bar, but that help can't be used as momentum into the first rep.
- The service academies' Candidate Fitness Assessment (CFA): The U.S. Naval Academy's instructions say not to swing, kick, or bicycle your legs on the way up. The scorer must not let the candidate jump off the ground or a chair to gain momentum for the first rep, and may steady the candidate by extending an arm in front of them on each rep.
- Norwegian conscript selection: In the testing protocol reported by Aandstad (2021), an accepted rep was done in a smooth and controlled manner, and kicking or swinging the body was not allowed.
The Marine Corps order doesn't say your body can't move at all. What it rules out isn't the movement that naturally comes with a pull-up but a pendulum-like swing that helps you get up, and whipping, kicking, or kipping the body or legs isn't allowed in its own right. Where one rep starts and ends (chin height, straight arms at the bottom) is covered in the pull-up form post. The Marine Corps scoring table, the academy max, and how scores were spread at Norway's conscript selection are in the average pull-ups post.
Counting kipping pull-ups: where momentum gets in the way
Momentum becomes a problem not because the movement is bad, but when you compare numbers. In the studies above, kipping raised lower-body and trunk signals and lowered some upper-body signals. Ten reps with momentum mixed in and ten reps without it are numbers where your muscles were used differently, and a count that mixes the two makes it hard to tell whether you've improved since last time. In a CrossFit workout for time, 10 kipping reps are a legitimate score; on the Marine Corps PFT, those same 10 could count as zero. The question isn't which one is right, but which standard you counted by.
The same thing happens with the app's prescriptions. PULL UP KING sets your starting level from your count in a one-set level test. If you can do at least one bodyweight rep, you start at the level whose first set is closest to 75% of that count, and the level test is counted with the same judging used in workouts. Whether you filled a session depends on whether the count in each set reached its prescription. So if you mix momentum into your level test and then do your sessions without it, your prescriptions are set to the count with momentum. Doing it the other way around throws things off just the same. The full rules for moving up a level and repeating one are in the pull-up program post.
How PULL UP KING counts reps done with momentum
The app's camera watches one thing: your chin. A judging line is drawn on screen as a dashed line just below the bar, at about elbow height, and your chin has to cross it for a rep to count. The app explains that the line sits below the bar because camera angle and joint detection both carry some error, and judging exactly at the bar would throw away reps done properly.
The judging code reads a single signal: how far your chin is from the judging line. If that signal stays above the line for two frames in a row, you're counted as up. If it drops below the line by more than 0.3 times the on-screen distance between the bar and the judging line for two frames in a row, you're counted as down. One round trip, up and then back down, is one rep, and coming down without having crossed the line doesn't count.
Nothing in this judging checks whether your body swung back and forth or whether your arms fully straightened at the bottom. So a kipping rep counts as one if your chin crosses the judging line and comes back down, and a strict pull that falls short of the line doesn't count. In other words, a rep the Marine Corps PFT wouldn't have counted can count as one in the app.
Attempts that don't clear the line are kept separately. Once the app has seen you hanging with straight arms in that set, any attempt that rises at least 70% of the way from your lowest chin height in that set to the judging line, but doesn't cross it, is left out of your count and tallied as a near miss. Near misses show on screen during the set and on the results screen, where the description reads: "They do not count toward your target, but the effort was real." The rule is the same whether you used momentum or not.
The times the app records for each rep aren't used to detect momentum either. For every rep, it records the moment your chin crossed the judging line, the moment you reached your highest point, and the moment the rep ended. Below each set's video it shows "Per rep" (the average gap between the moments one rep and the next crossed the line) and "Descent" (the average time from the highest point to the end of the rep). The coach's tip in set analysis points out only whether you drop on the way down, the camera angle, and whether you drift toward the left or right of the screen. It never brings up momentum.
So you check for momentum yourself, on video. "Auto Video Recording" in Settings records every set so you can look back at your form. Filmed from the side, your legs moving back and forth stay in a single frame, and the pull-up form post also suggests filming a set from the side to check every rep.
FAQ
Are kipping pull-ups cheating?
It depends on which standard you count by. In CrossFit workouts for time or for reps, the kipping pull-up is the default unless stated otherwise, and CrossFit describes it as a movement for endurance and stamina, with a different application. The U.S. Marine Corps PFT, on the other hand, doesn't count kipping reps.
How many strict pull-ups should you do before learning to kip?
CrossFit's guide recommends the strict pull-up as a prerequisite for the kipping pull-up, but the guide page checked for this post doesn't give a number. If you can't do a strict pull-up yet, it says to do the later steps of the Level 1 progression with your feet on a box. The steps to follow when you can't do a single one are laid out in the post for when you can't do a pull-up.
How is a butterfly pull-up different from a kipping pull-up?
CrossFit describes the butterfly pull-up as similar to the kipping pull-up but with a somewhat continuous circular motion, and says it's used in competition to speed up reps. Before you try it, the guide recommends capacity in strict pull-ups and high proficiency in kipping pull-ups. In the Williamson and Price study, both movements showed higher lower-body signals and lower upper-body signals than the strict pull-up, but it was the butterfly pull-up that showed a lower biceps signal, and the results differed between phases.
Does the app count reps done with momentum?
If your chin crosses the judging line and comes back down, yes. PULL UP KING doesn't judge whether you used momentum or whether your arms fully straightened at the bottom. So decide for yourself which way you'll count, and keep it the same for your level test and your sessions. To compare against a standard like the Marine Corps PFT, count each rep separately on video filmed from the side.
Kipping or strict, every rep meets the same line
The camera counts one rep when your chin crosses the judging line (a dashed line just below the bar, around elbow height) and comes back down. It doesn't judge momentum, so pick one style and stick with it. Attempts that get right up to the line but don't clear it show up separately as near misses.