Should You Be Locking Your Knees?

"Don't lock your knees!" This is a cue many of us hear consistently!

On the other hand, if you’ve ever practiced Bikram yoga, then you were told to always “lock your knees”.

Maybe you were told to "Always keep a small bend in your knee."

What now? Make up your mind already! 

Should you be locking your knees, or always keep a bend in your knees? Well, neither of these cues is correct. Here's the truth: 

When Standing, Your Knees Should Be Straight, Not Locked

You most likely fall into one of the following categories: 

1. Hypermobile

The muscles, tendons, and ligaments around the knee are supposed to stabilize the joint. Being hypermobile (read loosy-goosy joints), your ligaments are genetically long and lax, which means they’re not doing a great job stabilizing my joints. You can probably touch the floor with your hands pretty easily when bending forward in a standing position.

The only option for a weak knee to endure long periods of standing, is to lock, which puts it into a pseudo-stabile position where the two bones that form the knee press against each other and lean lazily against the ligaments. After doing this for hours, your knee joint might complain in the form of discomfort or pain. You might describe it as “my knees are tired”.  

In order for our legs to provide a stable foundation for any upper body or trunk movement, we need to keep our legs actively engaged. Locking your knees will turn off the muscles around the joint and can even cause you to faint due to reduced blood flow back to the heart. 

2. Very athletic who neglects stretching

On the flipside, in (endurance) athletes such as cyclists, or runners, or anyone who's sitting most of their waking hours, the muscles on the backside of your legs (hamstrings and calves) might have become shortened. This pulls your thigh and lower leg bones towards each other, which bends the knee. If those muscles are not consistently lengthened, then your knees will lose their ability to fully extend (straighten). The body very efficiently gets rid of what it doesn’t need. How’s that for a twist on “Use It or Lose it”?!

How To Find The Correct - Actively Engaged and Straight - Position For Your Knee

I'm about to show you an extremely easy and quick fix for your knees. But remember, what’s easy to do is also easy not to do. And because I know tons of smart sayings, here is another one: “Wisdom is not doing, wisdom is remembering.”

Step 1: Lock Your Knees

Push your knees all the way back as far as they go. This might feel common to you - if your knees like to hyperextend, like mine) - or this might feel extremely uncomfortable to you if your usual pattern is to keep your knees always bent. Stand sideways to a mirror. Can you see that the leg has a slight backward curve to it?

Step 2: Bend Your Knees

Now do the opposite: bend your knees. But just a little bit, just enough that you feel that they are bent. Notice that it feels like the leg has a forward curve. Which it does, of course. It just seems a lot more obvious in this position.

Step 3: Straighten Your Knees

Now we'll find a position that's somewhere between the two previous ones, where it feels neither bent backward nor forward. Now your knee is straight, but not locked. It might not feel stable (yet), just straight. 

Here is one more cue to help you straighten your knee out of the locked position:

Resume the (wrong) locked position again, and then think of pushing the calf muscle against the shin bone. Or imagine someone is pushing against your calf from behind you with a lot of power and you are fighting them by stabilizing your lower leg (you don't allow them to push you around). Immediately, you should feel the muscles of the whole lower leg engage.

What's Habitual Feels Correct, Even If It's Not 

Remember that correct alignment does not always feel right at first. We perceive as right what we are used to, what’s familiar. In the beginning, you will need to remind yourself often to unlock your knees, until it has become second nature.

Depending on which extreme you're coming from (locked or bent), your knees might feel way too bent or totally hyperextended, even in the correct actively straightened position.

A great Pilates exercise to help you repeatedly find the correct actively straight position, until it's in your muscle memory, is Footwork on the Reformer. Each time you push the carriage out you have to find the position, where your knees are straight, not locked, and not bent.

Here's a verbal cue I use all the time for this:

"Imagine your legs are rubber bands. As you push the carriage out, you pull the rubber bands long. There is no endpoint or stopping point, you just keep pulling until you decide to change direction and allow the rubber bands to slowly shorten." 

This cue keeps the muscles in your legs engaged without ever turning them off and locking them. But it emphasizes length and stretching at the same time.

Besides thinking of the actively straight position (which trains your mind and motor control), I highly recommend you practice specific exercises that lengthening or strengthening (respectively) the tissue itself.

Exercises That Correct Hyperextended Knees

If reminding yourself over and over doesn't fix your hyperextended knees, you should think about practicing exercises that strengthen your hamstrings, such as

• Single Leg Kicks,
• Double Leg Kicks,
• Back Control and Leg Pull, 
• Bridging with your feet on a foam roller or stability ball,
• Bridging on the Reformer, 
• Hamstring Curls on the Reformer
• Hamstring Curls with Magic Circle
• Hamstring Curls with Ankle Weights

Exercises That Correct Bent Knees

If you have a hard time totally straightening your knees, then you'll need to spend (much) more time lengthening your hamstrings, with exercises such as:

• 3-Way Stretch on the Reformer, 
• 3-Way Stretch with a yoga belt, or magic circle
• Ballet Stretch: Hamstrings on the Ladder Barrel
• Standing Hip Stretch on the Reformer
• Single Leg Footwork on the Trapeze Table/Tower (Cadillac)

If you are looking for more ideas of how to keep your knees unlocked, I invite you to join the Pilates Encyclopedia membership. You'll find articles regarding knee pain, hyperextended knees, bow legs, knock knees, and much more.