Where is our strength generated from?
Nervous System:
Periperal and Central
Neural development is actually not well understood. Evidence such as EMG testing has shown that NS adaptations do occur in both recruitment of the agonist muscles as well as de-activation of the antagonists. Or in some cases, co-contractions of the agonist and antagonist.
Reciprocating movements are where most of the adaptation seems to occur. This would include something like jumping where you crouch and then leap, or in our world, a squat, benchpress or any movement where there is an eccentric and concentric movement.
One area that is emphasized in both weightlifting and powerlifting is speed. Nervous system activity plays a tremendous role in this arena. If you take two similar sized men who are roughly equal in proportion and experience in pitching a baseball, why does one throw the ball faster than the other? Muscle size is not the answer. In a pitch where the arm reaches extension via triceps contraction we observe what is referred to as a tri-phasic burst pattern. Phase one is the initial extension of the arm where the triceps is contracting. Phase two involves a contraction of the biceps, the antagonist muscle in this situation, which is meant to slow the extension down to avoid elbow trauma. Phase three is the completion of the triceps contraction to terminal extension and release of the ball. The pitcher with the fasted throw experiences a later contraction of the antagonist – the biceps. This is purely nervous system control. The idea of doing lighter “speed work” where weight is of no concern but simply moving as fast as possible is intended to “train” the nervous system to apply the brakes later in the movement. So on a bench press, the biceps will fire just prior to lockout.
Another example of nervous system adaptations can occur within a single workout rather than adaptation over time. Begin a squat workout by unracking 135lbs and doing a set of 3. Keep doing sets of three until you are warm. Let’s say 10 sets of 3 does it for you. For this example let’s say you have a squat max of 600lbs and today you need to hit 90% for a single or 540 pounds. Now you are warmed up with 135. Now go straight to your working sets of 540 pounds for a single.
By working up with what we refer to as “ramping up” you would squat 135 for several sets of 3 to 5. 225 for several sets of 3. 315 for a triple. 405 for a single. 455 for a single. 495 for a single. 540 for a single.
Even after lifting a significantly higher volume of weight, in the ramp up your nervous system is now acclimated for a 540 pound squat. It should move quite easily as opposed to the jump from 135 to 540 which would crush you.
Energy: ATP
Food is fuel. I don’t even think this element of strength needs to be expanded on beyond – if you don’t eat enough, your work will suck.
One thing I actually would say beyond this is that carbohydrates, not fats should be your go to source of fuel for strength training. Lower reps, and totally anaerobic in general means you will not tap into fats for energy. I’m sure the keto crowd will disagree here and yes you can have energy while in ketosis. However I do not believe based on the evidence and the physiology of the human energy system that fat is a greater source of energy than carbohydrate.
Musculoskeletal System:
Skeleton
Let’s look at a very obvious example to illustrate how the skeletal system impacts strength:
In this picture above, you can see the acetabulum. This is where the ball at the top of the femur sits in the hip. On the left, you see an acetabulum that points forward and down. On the right you see one that points straight out to the side. If in a squat, maximum recruitment of the hips is achieved by lateral rotation of the femur, who do you think is going to squat more weight?
I’m a lucky SOB where the hip on the right is how mine looks. It has its drawbacks of course, like I can’t tuck my feet well on the bench for a big arch, but who cares about benching? My hips allow a very wide stance, a ton of hip drive and a more upright torso.
Limb lengths are another consideration. I coach a 123 pounder with a big deadlift. He is able to leverage his body weight very well due to the length of his arms in relation to his torso or legs. However his bench press suffers due to the long range of motion. Transversely, someone with T-Rex arms will likely have a massive bench and a poor deadlift – with exceptions to both of course.
Over time, loading of the skeleton will increase bone density in response to the stress.
Muscles
Once you have maximized leverages, building bigger muscles will assist in moving more weight. Big muscles, have larger fibers – moar weight.
Connective Tissues
Fascia, ligaments, cartilage and tendons – these are what hold you and your joints together. Weak connective tissues leave joints unstable and lead to injury.
Your tendons are there to transfer the force generated by the muscles to the bones. An example is when you squeeze the pectoralis, the muscle pulls on the tendon attached to the humerus which draws that bone in towards the midline. Weak tendons will either snap or not fully transfer energy.
The fascia eventually becomes part of the tendon so the same rules apply there. I will add that the fascia can become somewhat glued together. These adhesions or knots can hinder contractions.
Ligaments connect bone to bone. In your knee for example if your ACL – a ligament – was unstable, too long, or strained you will suffer injury or at least lose strength due to instability in the joint.
So those are some of the top physiological reasons we get strong… I haven’t touched on mental capacity. An article like that would take weeks for me to right. However sport psychology is a huge interest of mine and I might actually attempt it. For now I’ll just leave it with two points – positive mental imagery and self-efficacy.
But things like Wilks do a good job of letting you know how your strength compares in rarity across lifters of different sizes.
