Double Unders in Crossfit

Most CrossFitters out there may disagree with the statement that double unders are as easy as air squats. But think about it for a minute. Double unders do not require a tremendous amount of strength. One only needs to hold 4 ounce handles in their hands and rotate a 3 ounce jump rope around their body. One doesn’t need a tremendous amount of explosiveness. They only need to get off the ground 3 or 4 inches. And one doesn’t need to be extremely flexible. In fact, double unders probably implements the least amount of range of motion of possibly any CrossFit movement. So, what’s the problem? I propose that it is simply a case of misunderstanding or better yet “lack” of understanding.

In fact, so many CrossFit movements have been over analyzed, over studied or over coached but not the double under movement. Yet, double unders are the one that cause more anguish to so many CrossFitters. We are honored and excited to be one of the earliest pioneers to identify the sport specificity that CrossFit brings to the world of jump ropes. And we’ve built our entire sizing methodology and teaching philosophy around our discoveries.crossfit-double-under

Let me start by first pointing out there are various disciplines of jumping rope. For example there are speed rope and endurance rope athletes, Freestyle jumpers, Competitive Double Dutch jumpers, Boxing and MMA style jumping, all of which have their own sport specific principles for sizing and implementing their rope to best suit their sport’s goals.

Now that brings us to the CrossFit style of jump rope. Our biggest challenge was finding the balance between sizing the athlete’s rope to put them in ideal mechanical positions yet allowing variance for the athlete to adapt as they experience various levels of fatigue due to the wide array of movements they may encounter.

If you are familiar with CrossFit then you know that you can expect to see multiple movements during one work out. The typical design of a CrossFit work out will attempt to push the athlete to their lactate threshold while bouncing them between gross motor recruitment patterns to fine motor recruitment patterns and everything in between. It is crucial to have a rope that can accommodate those changing dynamics. Our sizing methodology and teaching philosophy were both designed to address those exact needs. How do we know if we got it right? Well, the top three female finishers in this year’s CrossFit Games all used Rx Jump Ropes and followed our sizing recommendation.

So, what’s the big secret you may ask? Well, it’s a four-part answer but here it is.

  • Get a rope that’s sized to your body and weight properly for your coordination level (heavier is better for learning).
  • Learn proper bounding mechanics so that you can efficiently and consistently rise and fall in the same spot.
  • Learn proper rotational mechanics so that you can move the rope around your body effectively with the least amount of fatigue inducing habits.
  • Learn the proper timing and tempo between your body’s motion and the rope’s motion so they have the greatest opportunity to miss one another at the intersect point, which is at the ground.

We follow 2 basic principles with regard to jump rope length; 1 is static rope length. That’s the actual length of a rope not in motion. 2 is effective rope length. That’s the rope in motion where the athlete’s mechanics can influence the length of the rope. The goal is to find the right blend of the two to best suit the individual athlete.double-unders-1

So, let’s begin with the static rope length and talk about how the jump rope should fit an athlete’s body. It’s very simple and systematic. It starts with the anchor point, which is the hand placement. We like to see the hands positioned at midline axis and right at the frontal plain. Placing a PVC pipe across the midline is a great visual que. The hands can slide in or out along this axis depending on the shoulder’s external rotation flexibility but the hands should never venture far from this anchor point.

Next we like to see the elbows relaxed down by the athlete’s side with shoulders as disengaged as possible. Again external rotation flexibility may dictate whether the elbows need to pull backwards a little in order to keep the hands from shifting to far forward. Allowing the hands to shift forward off the frontal plain would move the jumper’s body too far behind the center of the rope’s arc and cause the rope to recoil off the ground and into the jumper’s toes.

Once we have the anchor point isolated at the midline axis we then look for the jump rope to have an even turnover with approximately 12 inches of clearance overhead and a bottom out point 12 inches in front of the toes. If we’ve met all of those standards then we’ve placed the athlete in the best possible position to have balance and symmetry between their body and their rope. It will now only depend on the athlete’s efficiency of mechanics to dictate their effective rope length.double-unders-2

The athlete can do so many things once the rope is in their hands to either shorten or lengthen that rope once they send it into motion. The most common fault is placing a death grip on the handles and “freezing” the wrist joint so that the handles stay flat and parallel to the ground. This not only moves the rope’s connection points far apart from each other drawing the rope towards the jumper’s toes but also promotes a shoulder pump motion that leads to undue fatigue. A more efficient method is to lightly grip the handles with the fingers (not in the palm). This will allow the wrist to disengage and act as a swivel. As the hands now move along with the rope allowing the handles to turn down, the athlete can gain several inches of “effective” rope length as the rope passes under foot.

Another common fault is a misplaced anchor point. Hands placed too low near the jumper’s thighs will cause additional slack and increased friction at the rope’s bottom out point as well as bring the rope close to the athlete’s head. Hands placed too high will obviously draw the rope up and in towards the toes increasing margin for error. And hands pressed to far away from the core will also shorten the rope drawing it closer to the athlete’s toes. The ideal scenario is to isolate the anchor point from which the athlete’s body can maintain a consistent and centered relationship within the rope’s arc at all times. Once accomplished it’s a simple matter of syncing up the timing between the feet and rope so that the athlete’s toes leave the ground a split second before the rope passes under. This principle applies whether performing single unders, double unders or triple unders for that matter.

Now some simple methods to derive the ideal rope length are to take the athlete’s height and add a specific amount to it to derive the final rope length excluding the handles. Below is the model we use.

Athlete height: 5’5” or shorter – Add 2’10”
Athlete height: 5’6” to 6’4” – Add 3’
Athlete height: 6’5 and taller – Add 3’2”

We always leave the handles out of the equation because of the variety of sizes available on the market. Measuring the rope length only will ensure better accuracy.

A second method is to take a round trip measurement from the base of the athlete’s chest near the nipple, down under one foot and back up to the same point on the chest. Make sure the athlete is standing tall and upright in their bounding posture with feet flat on the ground and wears their normal work out shoes while taking the measurement.double-unders-3

Invariably, the two methods will derive a length within a couple inches of each other in which case choose the longer measurement. If by chance the two measurements are significantly apart from each other by more than 3 inches then take the average of the 2.

The principles that I just described are based on the broadest common denominator, the average athlete. As an athlete progresses to higher levels of efficiency and mechanics it is not uncommon for that athlete to reduce their rope length which speeds up the turnover rate but also forces the athlete to operate at much tighter tolerances between their body and the rope. The key is to find the right tolerance levels that the athlete can operate successfully across broad time and modal domains with jump rope in hand.

Our teaching philosophy is based on the mantra “Decrease Your Variables and Increase Your Odds for Success”. Follow that mantra and master those principles and the rest is as easy as an air squat. Now go double under till you double over!

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