Flexibility vs. Mobility

These are two fitness terms often used in conjunction with each other, so I'll try to clear up some confusion right off the bat: flexibility and mobility are two different things.

Flexibility refers to the range of motion you can stretch, passively or actively, a muscle before it snaps off the bone and hits you in the eye. More or less.

Mobility refers to the range of motion you can use a muscle effectively.

Here is side-by-side comparison of a female yogi demonstrating flexibility, and a ridiculously photogenic weightlifter demonstrating mobility:

Side note: a google image search for "flexibility" is the closest thing to porn you will see with safesearch still on.

Both of these girls have great hip, knee, and shoulder range of motion. The one on the right, however, is going to stand up with a big weight at the bottom of her position. She is demonstrating mobility. The girl on the left has "gotten into position" by pulling her hip past the point where it ceased being strong for the sake of a stretch. She exhibits great flexibility.

Think of flexibility as a bucket, and mobility as the water you have available to fill that bucket.

Now, I'll be the first to admit that I think flexibility and mobility work are both hella-boring. I'll also admit that I get jacked up something fierce when I stop stretching and mobilizing, so I understand that these are the raw broccoli to my weightlifting's tender juicy steak.

And while the two are not the same thing, they are both, unfortunately, important.

Increasing your flexibility changes the resting length of the muscle and makes them less resistant to being pulled to the end of its range of motion. This is usually touted as a great means of injury prevention. And it is....but not by itself. In fact, flexibility without mobility may increase the likelihood of injury by making it easier to get into positions in which you are not stable. 5 gallons of water in a 10 gallon bucket is just a lot of wasted bucket.

Increasing your mobility, on the other hand, makes you more capable of moving effectively through a large range of motion. Look again at the ridiculously photogenic weightlifting lady above: she's not only showing better flexibility throughout her shoulders, hips, knees, and ankles than most people, but she's supporting a heavy weight in a fairly stable manner at the "edges" of her range of motion. That is good mobility.

I know it sounds like I'm trumpeting mobility over flexibility... and I am. But mobility is certainly enhanced by flexibility, and the latter can aid in releasing chronically tight muscles that are the cause of a pantheon of non-weight training related injuries.

So when should you be working on these qualities?

Mobility work should be a staple in your warm up, and not just limited to what muscle groups you plan on working out that session. Hip, knee, ankle, and shoulder mobility work can and should be a daily occurrence. Don't know how? Why, here's a video, free of charge!

https://www.youtube.com/watch?v=7L5KVw2Pwic

Flexibility work can be done literally anytime, ever. Before your workout, after your workout, or my recommendation, on a completely separate day from weight training as part of a recovery protocol. Taking a yoga class has become my favorite way to incorporate stretching into my fitness routine. The common myths about stretching before workouts decreasing strength, or stretching after workouts to take advantage of pliability, are largely untrue. But that's another article.

Hopefully you know just a little bit more about these terms than you did before.As always, if you have any questions about this article or any other, please leave a comment or send me a message on Facebook. And if you haven't liked our page at Skape Fitness yet, we're totally not friends anymore.

Go forth, mobilize, and lift heavy things.

A Plea for Depth

"Go through a full range of motion" is the exercise equivalent of "eat your vegetables"; we've been told by our trainers/mothers that it's important, but we don't like to do it and will find every excuse we can not to. There are many different reasons to only go through a partial range of motion on any exercise -you can put more weight on the bar, you can get more reps, it seems safer- and they all have one thing in common:

With very, very rare exceptions, a full range of motion (ROM) is a requirement for optimal progress and safety. And in no exercise is the more important -or more widely ignored- than the squat. 

The squat is a scary but misunderstood beast. When broken down in to all of it's separate components, it's one of the most technically complex movements of the human body. I have textbooks with literally entire chapters  devoted to this one lift, and for good reason. However, when done correctly, the squat is perhaps the most effective, efficient, and safest exercises you can do in the gym.

Unfortunately, "correctly" means "to full depth", and this is where most people fall short (pun absolutely intended). "Full depth" means that your femur is parallel to the ground, and the crease of the hips is just slightly below the top of the knee.

Correct depth

Way too shallow. 

The head may be lower, but the hips sure aren't. 

When someone doesn't want to squat to full depth, the most common reason they give is that it hurts their knees.

This makes absolutely no sense.

You don't do partial push ups to save the elbows, and you don't do partial squats to save the knees.A review of squatting kinematics by the Journal of Strength and Conditioning Research (man, what would I do without them?) reveals that full squats are actually superior to knee extensions and partial squats during rehabilitation for a knee injury.  In fact, a partial squat is actually worse for your knees. In a partial squat, most of the stress on your knee is generated by the quadriceps pulling your tibia forward. Repetitive, one-directional pulling on any joint, knee or elsewhere, is a recipe for injury.

However, at the bottom of a full squat, the hamstrings kick in and balance the anterior stress on the knee with an opposing force. At full depth, with correct knee and foot position, the anterior and posterior forces acting on the knee are balanced. Balanced forces = safe knees.

Figure 2-11 from Mark Rippetoe's book Starting Strength, showing the forces acting on the knee at the bottom of a full squat

And no, lunges are not safer for your knees. Knee range of motion is knee range of motion.

The key here is technique. Some of the things I see people do when trying to squat (see above) are absolutely bad for the knees, and that's why proper form is so important. If you can't squat correctly, you're better off avoiding the exercise. But you'll really be missing out, and I suggest putting real effort into learning the technique and gaining the mobility necessary for a proper squat. Remember, as a personal trainer, I'm here to help you with both.

Here's a simple exercise to practice getting to full depth, which also doubles as a fantastic mobility routine for the hips.

Stand up straight with your feet shoulder-width apart and your toes pointed about 30 degrees outward. Sit down between your legs, and drop your butt as low as it will go without coming up on your toes. Put your elbows between your knees, and push them out so they track over your feet. Try to sit a bit lower. Hold the stretch for 3-5 seconds, stand up by driving your hips up and forward, and repeat for 10 reps.

A strong, full-depth squat is one of the best indicators of total-body strength and mobility we can measure. At Lift, we include it in our warm-ups, our strength and conditioning circuits, our athletic development programs, our weight-loss programs, our...well, you get the picture. We want you to get the most out of your workout, and that means doing each movement to its fullest. 

As always, go forth, get low, and lift heavy things.