Understanding Range of Motion: more is not better
Last week I spent a few minutes talking to a goalie scout for USA Hockey about what limits performance, and therefore what we must assess and train. This will be the first in a series of posts, in which I hope to present our approach to training and how our underlying philosophy of assess-train/monitor-reassess influences our programming and results.
Understanding Range of Motion
Range of motion (ROM) is often referenced using other words like mobility or flexibility. It’s also largely viewed as a “more is better” quality and increasing ROM is often misunderstood as being protective from injury, despite research evidence to the contrary.
In order to understand whether it’s necessary or desirable to improve ROM, it’s first necessary to understand what can limit it. Each of these could be the topic of their own post (or book), but in the interest of providing a broad overview, ROM can be limited by:
1) Bony Structure
The shape and contour of articulating bones (e.g. the bones meeting at a joint) can influence ROM. As one example, I’ve written a lot about how the shape of the femoral head and/or hip socket can influence hip flexion and therefore squat depth (among other patterns): Training Around Femoroacetabular Impingement, Performance Training: Adaptations for Femoroacetabular Impingement. For another good example, check out this article from Dean Somerset on how pelvic structure can influence lateral movement (See: Pelvic Arch Design and Load Carrying Capacity
You can’t stretch your through bony blocks.
2) Passive Restraints
Every joint, to some degree, is supported by ligaments that “check” ROM in certain directions. For example, the MCL of the knee helps prevent the inside of the knee from “opening” too far. Collectively, the surrounding ligaments help create some stability around a joint, and also provide feedback to the brain about where the joint is, how it’s moving, and how much load is being distributed across it. It’s quite possible, albeit almost never desirable, to stretch these restraints to allow more range of motion. This is extremely common in athletes like figure skaters and gymnasts.
Unfortunately, when these passive restraints are compromised, accessory joint motion is increased, meaning there is a little more sliding, gliding, and rolling within a joint, which ultimately increases the stress placed across other structures meant to improve joint congruency like the knee meniscus, hip and shoulder labrums, spinal discs, etc. This is one of the reasons why there is such a high incidence of osteoarthritis among these sporting populations, especially at young ages (e.g. <35 y/o); they’ve compromised some of their passive restraints so there’s more progressive erosion-like wear and tear across the joint.
3) Active Restraints
The muscles around joints provide active support. There are many reasons why a muscle/fascia may restrict motion around a joint, but I generally think of them in two simple buckets:
- The muscles aren’t strong enough to maintain stability in a certain range
- The brain interprets a certain position/motion as threatening or dangerous.
While very different, both of these buckets provide very simple explanations for why the various PNF methods work for improving ROM. Whether you view it as strengthening a muscle in a specific ROM, or simply demonstrating to the nervous system that producing force in a certain ROM doesn’t necessitate a painful/threatened response, the end result in situations where this is indeed the restriction is improved ROM.
The Big Picture
Hopefully, from this discussion, it’s apparent that improving ROM isn’t always desirable. Simply, there is always a cost to making improvement in any quality, and restrictions in ROM need to be interpreted on an individual basis based on what their structure allows. Attempting to force improved ROM beyond an individual’s structural capacity will necessarily lead to ligamentous laxity, excessive accessory joint motion and inevitably breakdown/degradation in the future. This may be the necessary cost of doing business for certain sports that require hypermobility (e.g. gymnastics, figure skating, etc.), but it’s advantageous to be aware of whether you’re increasing ROM beyond an individual’s capacity because it’s necessary to be successful in the sport or simply because you associate more as being better. In the case of the latter, if the improvements aren’t absolutely essential to the individual being competitive in their position within any given sport, the pursuit is not only a waste of time, it’s deleterious to their progress.
This is rarely the goal.
More specific to the origin of this conversation, careful attention needs to be paid to whether a goalie’s performance is actually being limited by their lack of ROM and whether this limitation is structural or functional, or whether the desire to improve ROM is based simply on the assumption that, within this position, more is better. Every individual brings different strengths and weaknesses to a position; maybe one individual’s strength is ROM, another’s is his/her ability to read the play and to position appropriately. I think we enter a dangerous situation when athletes and/or their coaches try to make improvements in any given athlete based on the desired profile of another without consideration to the structural and physiological strengths and weaknesses of the given athlete and the “role model”.
To be clear, I don’t think this is an easy distinction for athletes or sport coaches to make. Frankly, I don’t think most S&C coaches understand the difference. That said, one red flag to suggest you’re stealing ROM from an undesirable place is if you feel a restriction on the opposite side of the joint you’re stretching. For example, when you’re stretching your adductors/groin, if you feel a restriction on the outside/back of your hip, you’re not stretching anything, you’re jamming against your own joint’s restriction.
Optimizing Movement: Our System for Assessing Movement Capacity and Programming
This can be a tough distinction to make. If you have questions about your own personal situation, please feel free to post them below!
To your success,
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