In one of my WTF rants I discuss knee over toe and why, when it comes to human movement and rehabilitation of the knee, it’s a misinterpreted concept. I made a video link out in the book, now available to anyone interested, where I show the foot and it’s various axes to observe the nature of movement in the knee given certain movements in the foot.
In this video I use a very simple (non-validated ☺) ‘pen test’ which shows the angle of the knee in relation to the second metatarsal axis which is how it gives us an idea of how much pronation is present. The knee and the sub-talar joint axis generally follow each other through the gait cycle – which makes sense since the knee sits atop the tibia which sits atop the talus bone.
By locating the top and bottom of the second metatarsal bone we can create two points along which I can draw a line giving me a rough idea of the foot’s neutral axis. Observation of the knee posture in resting stance – for many slightly relaxed into pronation – I use a pen to reveal a perpendicular angle from the kneecap which shows that the knee is resting just inside this neutral axis… NOT even his resting stance is knee over toe… Many of you may immediately consider this a problem or label it as bad! We would simply consider it as ‘information’…
When simulating a front and back leg posture of walking (gait), I use the pen again, perpendicular to the kneecap and ask him to dorsiflex his ankle, which in a closed chain posture demands an accompanying knee flexion, you will see that his knee does not naturally hang around in that comfort zone of second toe here either. Chris is taking his knee inside the neutral axis in order to eccentrically load the muscle tissues so as to decelerate and protect the structure or global posture that he is entering into… By holding him at his end range and using the perpendicular pen test again, you can see the amount of movement that his knee would maximally experience with every step he takes… It’s natural for the knee to move inside second toe when the knee and ankle flex and the foot pronates. In running or activities when he is required to move faster this movement could even get bigger and will prove to be a problem (hence the potential ‘bad’ label) when his body is not prepped to comfortably enter this position which is inevitable in all sports and movement activities.
We’ll also watch the effort it actually takes to keep the knee over second toe…. In doing so you’ll notice that Chris loses his pronation ☹ something we want you to notice is so important in your gait cycle. By limiting motion here, promoting a knee over toe environment, you’ll be surprised as to how many structures (both muscles and joints) are deprived of the movement they could be undertaking in simultaneous moments.
Pronation is key in our movements…. It’s also easier to allow the knee to go inside rather than force it over the second toe.
In a training and conditioning world, even the therapy world, we are focused on keeping the knee over second toe. When undertaking this motion, this should be no (if not limited) motion in the foot itself; that’s 26 bones and 33 joints – all designed to promote movement through the whole body – not moving at all.
Promoting knee inside the 2nd metatarsal is a way of protecting the knee as it enters into this medial position. Structures such as the anterior cruciate ligament are designed to both allow and limit movement into this space. Muscles such as the vastus medialis, vastus lateralis, TFL, biceps femoris, medial gastroc, Sartorius among others are all muscles set up to complement the role of the ACL, all lengthening to allow movement into this medial space and contracting to control and decelerate the movement before contracting concentrically to bring the knee back towards it’s central resting position of knee over toe.
Movement is a migration of structures, away from, back towards and away from centre again in an endless journey of flow. (It’s this journey that is described for all muscles and joints in my Flow Motion Model and will become available in my next book – no date as yet!).
The function and role of all that was just mentioned from ACL to Sartorius (not to mention pronation and all the foot muscles responsible for managing that) is lost as soon as we go knee over second toe. Knee over second toe relies on bony alignment for stability rather than muscles, which are set up to create stability around the knee. For me there is a kind of irony there…
HAVING SAID THAT if you are weight lifting, squatting and deadlifting with what you consider to be heavy weights on your back, then no, you DON’T want to be deliberately taking your knee inside… however in an unweighted preparatory environment. We can see BIG and QUICK gains in the amount of muscle they use and the amount of weight they can lift.
So why do we think we should keep our knee over this second metatarsal axis in the first place?
Answer: Mechanical advantage. A rigid foot and a safe knee position makes sense biomechanically under a heavy load. A column of aligned bones makes for a safe lifting posture – however in human movement it is joint motion that triggers muscular reaction as described in my first two Big Rules of motion; #1 – Muscles lengthen before they contract and #2 Joints ACT; Muscles REACT – that is to say that without movement inside this 2nd metatarsal axis we fail to stimulate muscular involvement to protect the knee, foot and ankle from what is essentially a compromised position. By entering into a medial space, we encourage the foot to be a mobile adaptor, triggering foot muscles to wake up and join the party, we encourage the knee to enter it’s ‘dark zone’, triggering knee muscles to wake up and as we also describe in the book encourage the extensor chain muscles (muscles of ankle, knee and hip extension to be more active in the bodies mobility quest, these are the muscles that get our feet supinating, our knees extending and returning back to neutral and our hips extending via the glutes and hamstrings et al.
In summary, knee over toe is a biomechanically advantageous position but to not enter into medial postures with the knee in a safe therapeutic environment is to avoid innervating the very muscles that are designed to control the movement of that knee. At Anatomy in Motion we like to create a learning environment for the brain by moving structures into spaces they were a) designed to go, b) often are taught not to or c) struggle to get in and out of.
NB… foot pronation should not be encourages by driving the knee medialy but to allow the knee to follow the foot as it pronates. Subtle but very important difference ☺
Here is the video that this blog supports where you can see the lines I am discussing that represent the axes of motion.