Thanks for your comment. No issue taken :) And I’m glad to hear your out enjoying nature more!

I’m familiar with the notion that trainee’s shouldn’t allow the knee to extend past the toes due to risk of injury. I’ve see this advice offered all the time by personal trainers instructing lunge exercises especially. This is even what I was taught when I became a certified personal trainer through the National Strength and Conditioning Association.

However, I’ve since learned that it’s an incorrect assumption. For some people (most fitness trainee’s, in fact), it would be contraindicated to do exercises that involve extreme knee flexion under load because there are often pre-conditions that would lead to injury (poor mobility, stability, connective tissue strength, etc.). But this isn’t true of all people. Those who have healthy knees would be perfectly fine performing exercises in this fashion, and it would actually help them strengthen the joint capsule and the surrounding connective tissue and muscles.

The knee joint is most structurally strong when the leg is fully locked, knee fully extended. The second strongest position for the knee is fully flexed.

The key is to always work progressively towards all strength goals and movements. I follow a general progression when working with clients:

1) First, one must have the mobility to actually achieve the range of motion without any load on the joint. Open-chain mobility exercises would be the first step (ie standing single-leg, flexed knee circles).

2) Then, one must have the mobility under very slight load, so a closed-chain mobility exercise would be step 2 (ie standing knee circles).

3) Then, we can start adding additional resistance to the entire range of motion, taking extra care to work progressively. This is where exercises like the duck walk come in.

There are no bad exercises, only exercises that have either been misapplied or used in a poor context.

My understanding is that, in that position, the knee joints are no longer supported by both muscle and ligament and are thus prone to injury. (When doing other types of leg exercises, one is told to not let the knee extend past the foot for that very reason.)

Regardless, I’m hooked on the MovNat philosophy and now I seldom work out in a gym, I “play out” instead. It’s fun and seems more practical to me than isolating muscle groups and doing 3 sets of 10.

thanks for your comment, and for the tip!

I checked out your site a couple weeks back, linked from somewhere else I can’t remember – enjoyed the post about your new companion, Jackson. We’ve got another northern breed, an akita who you can see makes a guest appearance from time to time on my site.

Keep moving!