Assess, don't guess! And why the "perfect split" may not improve mobility

A few days ago, I asked our community to see if they can solve this problem...

1. Why is there a difference between my side stretch kick and isometric side kick hold?

2. How do I fix the difference?

Initially, many were quick to provide an all-encompassing solution. Some of them included

Solution #1: Rotating my pelvis more, and thereby changing my torso angle
Solution #2: Changing my hand position
Solution #3: Extensively stretching, and training splits
Solution #4: Increasing isometric load (i.e. duration of time) while holding the side kick
Solution #5: Using a different set of muscles
Solution #6: More ballistic kicks, with increasing heights

And then I posted a follow-up, with more information. I provided angular measurements using the same pictures, and then I added my not-so-perfect splits.

OOPS - I broke the internet...

Significant drop in engagement. Radio-silence.
And I expected it...

Our bodies are so smart, and so good at creating compensations just to achieve that final, picture-perfect shape that
​we think we know exactly what and how to move.

And I was right there with you, too. I've been there and done that. Remember, I was never flexible as a child, and only gained flexibility as an adult when I started training in martial arts. I was the student right there with you participating in countless of warm-ups with static stretches, ballistic stretches, partner stretches, and split work, and while my results were certainly more than I expected in my life,

I suffered a grade 2/grade 3 ankle sprain, and tore my ACL
within the first 5 years of my martial arts training
all on the same, right leg.

Something was wrong. Something wasn't working, and I needed to find out why...

Passive vs. Active ROM

1) Why the difference?

There are two qualities in achieving a range of motion, which depends on where it falls on the length-tension or force-length curves:

Passive range of motion occurs when an external load acts on you to move your joint into the end range. Gravity, momentum, and another person are examples of external loads.

The motion becomes active when you move yourself on your own to replicate that same position.

From the pictures above, you see a decrease in angular measurement from left to right (140 to 126 to 103 degrees). These demonstrate the spectrum between passive and active ranges of motion. And yes, the two overlap without clear delineation.

The science...

We know that the pelvis is involved in achieving some sort of hip mobility, but it is perfectly expected that the passive​ range of motion will be larger than the active​ range of motion.

Additionally, having sufficient passive range of motion is a pre-requisite to controlling it actively.

But how do we know if the active range of motion is enough?

The literature suggests that in order for active range of motion to be deemed acceptable for optimal movement performance and risk mitigation, the active range of motion should meet 85% of the passive range of motion.

Based on these measurements above, I do not meet this requirement (103 / 126 = 81.7%, based on dominant leg ROM). But does torso angle and hand position change these findings?

Temporarily, yes. But it does not permanently fix the gap.

Snapshots of left and right hip standing CARs used as FRA® due to camera placement

2) How to fix the difference?

The main reason for the difference between passive and active ranges of motion is due to neural resistance. Basically, my brain does not feel safe when my body attempts to enter that specific range of motion actively.

In the advent of all things internet, we have become extremely resourceful in accessing information, but interestingly, we are so quick to provide a biased solution with little to no significant information. And that solution is usually based on our personal experiences.

The proposed solutions did not attempt to evaluate if I was experiencing any kind of pain when performing one side kick pattern vs. another. They also did not attempt to evaluate if I had any significant history of injury or surgery that mechanically would impact my ability to replicate the desired movement pattern.

Learning and positive adaptation are not optimal when under excessive stress, when there is no neurological capacity available to process what is being demanded.

We all know this as students and educators, but we continue to persist in teaching without properly assessing which factors negatively impact the ability to learn and apply what is learned (in this case, movement).

Does your hip move like a hip?

Left Hip CAR transition

Left Hip AB FRA®

Right Hip AB FRA®

How do we assess why the brain does not feel safe when entering a specific range of motion? We use a Functional Range Assessment®. For example, we ask someone to move a hip joint to its end ranges without allowing compensations, and assess where the body either shows deficits in ranges of motion or unexpected coupling patterns to achieve a position or transition. These assessments give us direct access to the quality of tissues that impact how a joint moves internally - within its capsule.

If there is a restriction at the capsule, then we cannot expect global movement to occur with clarity, as the feedback loop of communication between the distal and proximal areas of the body is already compromised (CNS to PNS, afferent vs. efferent pathways).

We need to assess carefully in order to design an individualized solution to an individualized need. In my case, I have more restrictions in hip external rotation and abduction. In these series of hip abduction pictures, the left-most picture shows the snapshot of my hip CAR in transition from abduction + internal rotation to adduction + extension. This angle (with bent leg, 27 degrees) is extremely close to the linear assessment of just my hip abduction (22 degrees left hip). Both are performed without compensations.

What is not shown is my left hip CAR revealing Closing Angle pinch when moving into external rotation + abduction. If these are fundamental hip motions contributing to the side kick (bladed foot is a hip external rotation + ankle inversion), then continued pain and restriction at my hip joint will not improve my range of motion.

If my brain does not feel safe moving into a position unloaded, then how would adding load make it feel safer?

So let's critically assess each solution previously mentioned.

Solution #1: Rotating my pelvis more, and thereby changing my torso angle
Solution #2: Changing my hand position
Review: These provide temporary cheats to gain additional range of motion, but does not permanently address my hip pain.

Solution #3: Extensively stretching, and training splits
Review: Extensively stretching needs to be further clarified. If this involves passively stretching on the floor or with a partner, then it further trains the passive quality, thereby making the difference larger between passive and active, and thus, not solving the original problem.
Training splits also requires clarification, but traditionally it involves someone lowering oneself to the floor, and allowing gravity to do the work (passive). Plus, it adds additional external load to the joints.

Solution #4: Increase isometric load (i.e. duration of time) while holding the side kick
Review: How does adding load make my brain feel safer when it is already eliciting pain in the same motion without load?

Solution #5: Use a different set of muscles
Review: This is an unfortunate side-effect of memorizing the musculoskeletal system from your Anatomy & Physiology class. All tissues contribute to the production of range of motion, and it is virtually impossible to lock the sequences of neuromuscular engagement when performing a movement in repetition. What does that mean? It means that when you perform one movement over and over again, your body will not fire the same muscles in the same exact order when you repeat the movement.

Solution #6: More ballistic kicks, with increasing heights
Review: More passive component, with more external load that the body cannot handle.

How can I convince you to stop including splits in your warm-ups?

JCVD Split Punch

Is this functional?

So I'm having a little bit more fun with this now. This scene and countless others are what we envision when we attempt to achieve the perfect split for martial.

What? That didn't cross your mind? Really?
​But this is the "bunkai" of the perfect split, is it not?

In all seriousness, my hip certainly cannot handle this type of load at the moment. We took the time to critically review as to why training splits is not a specific input to address internal problems at the capsular level.

So the remaining question is, if it's certainly an option, why not try it anyway?

Unless I plan on sparring and falling into a split, either by accident or consciously just like JCVD, I then do not have a specific reason to further improve my passive range of motion as a striker.

But if I was a grappler, it's a different story. While having a passive range of motion sounds important in defense of a leg lock, a counter move requires strength. If I cannot exert force actively at the end range, then it would lead me to tap out much faster than someone who has the strength to create space and counter the lock. As many FRS legends have said, "You cannot move where you cannot move."

There are smarter ways to train hip mobility than just asking your student to "drop it like its hot", but it begins with a full assessment. 

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