So we’ve had a brief look at how people learn, let’s start to take it back to football a little, and understand how physics can help us block better. When I started writing this in 2015, I done so because my background is civil engineering, and physics and maths make sense to me. So because it was the easiest way I could think to describe how bocking should work, that’s what I done.
I note here, that since that point, LeChalres Bentley has done a much better job in explaining an OL stance, and why physics is important in football. If you haven’t seen his stuff, I thoroughly recommend you look at OLP (OL Perfromance), as they have some fantastic information out there.
Fundamentals
One of the advantages I think have, along with most non-US based coaches, is that I was not brought up with football, but played a variety of other sports that all include different movements, body types and ranges of motion. I feel this has freed up my mind to accept ‘different’ approaches to football problems.
OL play is based on inertia, momentum, physics, and understanding your body as an OL. We must make our movements the most efficient for our bodies, whilst obeying the laws of balance and physics. Effective blocking is essentially based on 3 things:
- Power comes from driving through the ground
- Hips must be set
- Hands and hips have to be in sync.
That’s it, 3 fundamental principles. We succumb to making the game more complicated than it is. Effective run blocking is based upon force generation and proper angles. How we use our body to create momentum, and how we transfer that momentum into the defender is the key. We’ll build on those points from the ground up.
The Basics – Stance & Movement
In order to be great OL coaches we first must study and understand movement, balance, joint position and movement quality. Only with effective balance and joint positions can effective movement quality be achieved. Not only does improper balance lead to less than optimal blocks, it more often than not also leads to overuse injuries.
In order to instill proper movement quality, we must understand how people learn, and how the body learns to move. A big part of the DN4 is to maximise motor learning to manipulate the external environment around the athlete. This means we use cones, hurdles and other tools to encourage proper posture, balance and rythym. We find that manipulating the environment, in combination with learning cues, is more effective than using only cues to effect movement quality.
Joint Alignment
Also known as centralising, or stacking, joint alignment essentially means that at any particular phase in the block, the joints are in the optimal positions to create the desired body position for that segment of the block. When the joints are aligned in a proper fashion, the athlete has the best chance to express optimal movement quality. Note, the joints don’t actually do the work, they aren’t the equation so much as they are the guide, to show you that you are getting the right answer.
In order to achieve these balanced positions, both athlete and coach must first understand what correct positions look like throughout the block, from stance through to finish, there are non-negotiables that must be correct. There is no universal boilerplate stance or block, where the feet should be x inches apart and the toes should be pointed at y angle. These positions depend somewhat on each athlete’s specific body type, coordinative qualities, strength and their basic principles of motion. This simply means there is no one right way to block; however there is a range of acceptable positions (a band width) of acceptable positions for each athlete to incorporate body type and movement style, whilst still being governed by the laws of physics.
The Stance
For years now, the coaching points for an OL stance have been:
- Ensure feet are pointing straight ahead.
- Slight offset in the feet – toe to instep alignment
- Shoulders square
These are outcomes. They don’t actually tell the athlete the how, only the what. As coaches it is our job to makes things as translatable to the athlete as possible. Explain what we are expecting and then tell the athlete how to do. I’m not going to copt the OLP stuff in here, but I genuinely believe it to be the best stuff available on the stance, so have a look at that!
The key to it is the process they go to to build each athletes stance. It’s about how the athlete feels, the cues they give athletes are like ‘Offset your outside foot back, far enough that if I pushed you from the front, you would feel strong in that position. That’s your strength position‘. Again, these aren’t external coaching commands, they are intrinsic to each athlete individually, but it allows you the functionality to coach multiple people at the same time. This is what we discovered in the last chapter, we give declarative (explicit) instructions, combined with non-declarative (implicit) associations for the athlete, and we immediately create something that is much more learnable.
The DN4 System
Firstly, as an edit to the book, I massively regret using the word ‘system’ in this. It’s puts me in a similar place to people who are offering accreditions to a ‘system’ for $500, and I don’t want to be a snake oil salesmen like that. Again, a big part of the reason why i’m putting all this out there, in the hope someone finds it useful. Anyway, back to the book….
Earlier, we noted that in essence, blocking can be boiled down to three key ingredients:
- Power comes from driving through the ground
- Hips must be set
- Hands and hips have to be in sync.
I would also add the generic term ‘finish’ to that list. It’s not a term I particularly like using, but it will suffice for now.
So there we have it, the DNA of blocking, four terms that covers everything we need, if we follow these steps, we will have executed a great block. Note here, there is no mention of first step, helmet position, or any coaching ‘terms’. We aren’t simplifying to make things easy, we are educating the players and giving them a better understanding of not just ‘what’ is expected, but ‘how’ the can accomplish that. When players understand how to achieve a certain movement they can execute correctly, consistently, when they can execute it correctly, they become natural movements.
Let’s look at each term in turn, and how we can simplify it to make it easy for athletes to remember, and create key coaching points that can be used quickly on the field during practices.
1 – Power comes from driving through the ground
Again, we aren’t talking about a first step here, what we are talking about is initial power generation, the torque our body creates to get us moving. It is everything up until the first step lands. That initial burst, the explosion, the initial…
PUSH
2 – Hips must be set
Direction is irrelevant at this point, what is important is the angle we set, we keep our hips on. This is important as the angle we set must take into account the worst case scenario for the offensive lineman based on what he can see in front of him, and what he has studied on game tape. What is just as important is that we stay balanced and strong in that position, and that we continue to generate…
POWER
3 – Hands and Hips in Sync
We have developed a lot of momentum over the first two stages; we must now transfer that into the defender. In order to do that, our hands and hips have to fire in sync, ensuring the most efficient transfer of energy into the defender. We must develop a great…
PUNCH
4 – Finish
An extremely generic term that tells no-one anything, We can finish strong (pancake blocks) or we can finish weak (throw the defender away because we have lost the battle), these are very different things. What we want to see after the punch is an OL staying engaged with the defender, staying balanced and control the block, We are looking for…
POISE
(It doesn’t take a genuis to figure out I mean balanced here, but that didn’t fit into the marketing of it all, so Poise was the best I could think of).
Here we have the 4 key words, easily learnable, and more importantly, enable us to identify in each phase of the block exactly what has went wrong, and convey that quickly to the player during a practice.
PUSH, POWER, PUNCH and POISE.
Before we move onto looking into these terms in more detail, we must understand the physics behind what makes a successful block
UNDERSTANDING THE PHYSICS
In order to successfully block someone, we must understand how blocking works, this means gently delving into the world of physics. I’ve always loved maths and physics; it’s what drove me into gaining my Masters Degree in Engineering. I am aware however, that I am somewhat in the minority, so I hope to break it down in a way that makes it simpler to understand and worthwhile.
For me this is a necessary evil, especially as a coach. We need to understand the individual elements of a block, how they piece together and how they can be harnessed. This is the coaching equivalent of working from first principles (in maths). In theory, as long as we understand the governing principles behind a subject, we should be able to solve any problem.
Newton’s Three Laws are:
- An object will remain at rest, or at a constant velocity, unless acted on by a force.
- The magnitude of force of an object is equal to the mass multiplied by the acceleration of the object
- When one body exerts a force on another body, the second body simultaneously exerts a force back of equal magnitude and opposite direction.
I get that’s all boring and no-one is massively interested in it, so let’s have a look at the governing principles behind blocking and how everything fits together.
Vectors
“A Euclidean Vector (sometimes called a geometric or spatial vector, or – as here – simply a vector) is a geometric object that has magnitude (or length) and direction, and can be added to other vectors.”
Vectors are fundamental in physics and engineering. I was first introduced to them when discussing bridge deck loading at university, and they are at their core, incredibly simple.
We use vectors as a way to represent the forces acting on something. Vectors are drawn as an arrow, which has a direction and a magnitude, so the bigger the force, the bigger the arrow.
Let’s look at an OL dummy in a stance:
All the forces within the lineman (i.e. his weight (mass x gravity)) are put through the ground, through the inside of his feet, the red vectors. The ground is placing an equal amount of force back (green vectors), this in turn keeps the dummy from sinking into the ground.
This is summed up by Newton’s Third Law above. The ground exerts and equal and opposite force, so everything stays at rest. Things start to get a bit funky when we when need to move.
Let’s look at the same dummy, having stepped with left foot:
What we can see here is that the force exerted by the dummy is much bigger (Newton’s first law), and this gives us an overall movement as shown by the big red arrow. This is how we achieve movement, by exerting a large force into the ground through our bodies.
So if we want to move quicker, we must exert a larger force. This ties in perfectly with Newton’s Law, F=ma. We can’t gain weight during a play, so mass is a constant; that means if we need to create a greater acceleration, we need to focus on creating more force.
This is why the DN4 focuses on the push, rather than the first step. The first step is the outcome; it tells players what you are expecting, but not how they do it. What we have shown above is that where the first step goes is almost irrelevant, what is important is how much force we can put into the ground quickly, to move our bodies in an explosive manner.
Resultant Vectors
The above examples look at vectors in a simple format, but what happens when two forces act on an object, but not in the same plane?
We simply add them together, so let’s look at this example of a ‘good’ block, and then we’ll evaluate it based on physics and what we know.
In this case the offensive player (in white) has ‘shot’ his hips, and is ‘rolling’ his hands over the top. He has clearly won this battle against a much smaller opponent. We can represent the offensive player by two vectors, the force of him ‘shooting’ his hips (VS) and him ‘rolling’ his hands (VR), as shown below (estimated forces and vectors):
This shows the force generated by ‘shooting’ the hips, in an upward and outward motion and the force generated by ‘rolling’ the hands. The force created by ‘shooting’ our hips is much larger than that created by our hands, due to the larger muscle groups at work. We can clearly see that these forces are working against each other, which will reduce the Resultant force (i.e. what the defender feels) as shown below:
What we can see above is that the forces created by the offensive player actually reduce the lift and torque that is naturally created by the ‘shooting’ of the hips. This means the vectors are working against themselves reducing their effectiveness, so the resultant force, or the force that is delivered to the defender isn’t as efficient as it could be. The resultant force is now more horizontal as a result of combining the two forces, and this is the plane of most resistance (i.e. The plane the defender can push back on the most). We want to reduce our opponents effectiveness, not reduce it.
We know that ‘lifting’ a defender is vital to a good block, but do we really understand why? Let’s have a look at power angles, and how they tie into vectors, and then we will revisit this block again.
Power Angles
Power angles are a common phrase used throughout football, and the ‘Z’ position is the most commonly taught. Let’s have a look at our OL dummy again in a good football position:
What we can clearly see is that we have two power angles in our body. When we remain in this position, with our muscles in tension, we have lots of potential power we can release into a defender. This is an optimal position to be in, when blocking someone; our hands are in front of our face, and have punched the defender before our bodyweight gets close (removing the head from contact as much as possible), our chest is close to our knees, our knees are inside our ankles, and our butt is close to level with our knees. This position is the most efficient and optimal way to block someone.
This isn’t new knowledge, OL coaches have been talking for decades about the ‘Z’ in the legs for decades; but the same knowledge also applies to how we block a defender. This position is powerful because it tightens all the biggest muscle groups in our body, and gets them primed to exert big forces. Our posterior kinetic chain (Hamstrings, Glutes, Calves, Lower Back) in addition to our anterior kinetic chain (Quads and Abs) house the engine of our bodies, these are the big muscles, the power generators. You don’t see many great OL who skip leg day is the point I’m getting too, the same can be said for Defensive Linemen. So how do we block these guys?
Simple, we segment, or separate, both power angles.
The simplest and best way to block a defender, in physics terms, is to remove the power units from the defender. If we can remove the power angles from his body, we remove his ability to fight back, therefore he will provide less resistance, making our job simpler. So how do we segment the power angles? We lift!
In these examples we demonstrate how the lifting of the body affects the two separate power angles. By pushing the upper body back, we increase the angle in the hip, therefore reducing the tension stored in the hips, glutes and quads, the biggest power storage units.
By lifting the torso, we also increase the angle between the lower and upper leg, reducing the power stored in the hamstrings and calves. It also means the defender is unable to readjust his weight, lower his hips, and get back into a strong position.
So we can clearly see that lifting increases the angles within the body and reduces the effectiveness of the defender to fight back. Again, there is nothing new here really, we’ve known for a long time that raising the centre of gravity of a defender is a good thing, but what this does do is redefine how we think about blocking. Let’s quickly go back to the vectors, and see what’s changed.
Resultant Vectors
The previous example of what is commonly described as a good block produced the resultant force shown. This is the angle and magnitude of the force that is transferred into the defender. Given what we have just learned about power angles, we can immediately spot the flaw in this technique.
What we can see is that the horizontal force generated by the player is more than enough to knock the defender back (VH), however there is insufficient lift (VV) to increase the lower body power angle, so the defender will be able to sink his hips, and fight back.
So we need to increase our vertical lift to better separate both power angles, and produce a resultant force similar to that shown. This force, when transferred into a defender will jolt him backwards, separating the upper body angle, but will also lift him upwards, separating the lower body angle.
Now we understand this, we have to rethink how we block people. Shooting our hips into a defender is great, but if we are still rolling our hands over the top of the defender, we are working against ourselves. Not only are our hips rising and our hands pushing down, a very uncomfortable position, but we aren’t being efficient, we are working against ourselves. We are exerting an inordinate amount of energy to do very little work. We want to maximise our output. A more efficient method would be to utilise our hips and hands working in a similar plane.