What's the first thing that comes into your head when you think of strength? The Hulk? Captain America? Or maybe something a bit more realistic, like Arnold Schwarzennhaeger circa 1980.
The common factor between all of these icons is obvious; they have huge muscles. The muscles are both a product of strength, and a demonstration of it. You can't gain muscle without getting stronger, at least not to the extent of our former examples. Most of the time, you don't get stronger without gaining the muscle that shows it. I say most of the time, because there are some people out there who get very strong without looking like someone from a superhero comic. Take the guy in this video for example. Walking by him in the street, he probably doesn't get many people staring at him thinking "Wow I bet that guy is strong." Nonetheless, he benches over 2.5x his body weight, an admirable feat for anyone.
The importance of this is to show that strength is not a quality based solely on muscular size. There are multiple facets to strength, and each of these are equally important.
Muscular strength: This is the one that gets the most attention. Muscles contract and stretch to turn energy into movement. They take the signals from your nervous system, and use the energy from your cells to produce movement. It stands to reason that the more relative muscle you have working towards the same movement, the easier that movement will be to accomplish. That is to say if you're trying to bicep curl 40lbs, you will be better equipped to do this the more muscle mass you have in your bicep region.
Neurological strength: Often overlooked is neurological strength. This is the main reason for the phenomenon known as beginner gains. Neurological strength is ability of your nervous system to send signals to the appropriate muscles for a given exercise. The stronger this signal, the harder the muscular contraction. If you're muscles are the engine, and cellular energy is the gasoline, then the nervous signals are your foot on the gas pedal. When you first begin strength training, or when you come back after a long break, this facet will experience the quickest improvement. This is because the first time you squat, or bench, or whatever it is you're doing, its going to be at least a little awkward. You have to get a feel for it. You have to learn proper balance, bar path, and what body parts to really focus on pushing or pulling. A dogsled is much more productive if all the dogs know what direction to run in instead of having to guess. Similarly, you will be stronger if you're not trying to figure out proper bar path and muscular contraction in the middle of a lift.
Mental strength: Mental strength is the biggest variable from a day to day basis. Where as your muscular strength won't drastically change from workout to workout, your mental strength might. Mental strength is the ability to properly motivate and guide yourself through a lift. What the proper mentality is for a lift depends on the person. Where as one person might need a mindset of intensity to really utilize his mental strength, another might do better with a mentality of cool focus. This is something where you figure out over time what works best for you. As I mentioned before, mental strength is variable. Maybe one day you really nailed a job interview and you're feeling confident going into a workout, but maybe another day you get dumped and you can't even find the motivation to get out of bed. Nonetheless, your mental strength it regards to lifting does improve over time.
These three facets piece together to create strength, but we still haven't answered the question of what is strength. Strength is the measure of how much resistance you can overcome. Basically, how heavy of weight you can lift. Strength is a relative measure, and the best point of measurement to relate it to is yourself. The point of training is to get stronger, and you are your own best measure of this. Not the guy on the next bench over, not the girl you see in the squat rack. Comparing yourself to them won't tell you how much strength you've gained. Only comparing yourself to yourself can do that.
Man I've seen that bench press video before, and it still blows my mind. If someone had told me about it I would say they were absolutely crazy.
No kidding. It still amazes me every time I watch it. How fun would it be for that guy to go to a gym where nobody knows him and bench that while everyone stares on in disbelief?
I mean, something like 1.6x bodyweight is 95%, what is 2.6x bodyweight??? lol