What could a person able to re-arrange their muscle strength accomplish?

Question

Suppose there is a type of person who is otherwise a normal human, but can temporarily transfer muscle strength from one part of their body to another. Whether this occurs through mutant genes, superpowers or magic is not material here. What can they do with this ability?

To make this (somewhat) more precise, assume the following:

• If the sum of the maximum force* that can be exerted by all the muscles in the person's body is X newtons, they can redistribute that total however they like. There may be practical reasons not to, but there is no technical reason they can't give one pinky the ability to move X newtons and have no strength in the rest of their muscles.
• All muscles are subject to the ability, including cardiac and smooth muscles.
• Ignore the potential to damage tendons, ligaments, bones, etc.
• The person in question is a reasonably fit human male of average size.**
• The strength transfer happens instantly. The person either instinctively knows how to reposition strength effectively or has been extensively trained.

The obvious combat application of this ability is to take strength from one's legs, smooth muscles and non-dominant arm to put into the dominant arm, and throw a super-powered punch (or leg for a kick). What I'm not clear on is the limits of this strategy. Obviously you couldn't take all the strength from your legs, or you'll collapse on the ground. No strength at all in your core and your guts fall out. There's also a question of leverage--a punch doesn't do much without leverage against the ground, right? (That super-strong pinky referenced above would be pretty useless). But perhaps one can compensate for weakness in the legs by standing in a position that relies more on the skeletal structure than the muscles?

Other combat applications? Non-combat applications?

* Despite some googling, I couldn't find a standard term for measuring muscle strength. In weight-lifting there is the "1 rep maximum", the maximum weight one can lift in a particular movement without injury, but that doesn't quite seem right here. If there's a measure I'm missing, let me know in the comments and I'll update the question.

** In practice, it would behoove someone with this ability to make every muscle in their body as strong as possible. Average human male chosen just to have a baseline.

Answer 1

This could be useful in some grappling situations, but it's surprisingly not useful in most situations. The surprising reason for this is that most combat arts are already designed to permit one to engage a remarkable portion of one's muscles when attacking. Proper boxing punches, for instance, are designed to let you get the maximum benefit from your leg and core muscles.

The real power of your character would not be in their ability to apply their muscles to support a punch, but rather their ability to do so in otherwise indefensible positions. As an example, much of grappling focuses on taking away the ability of an opponent to apply their full core strength against you. Done correctly, this means you get to apply the full strength of your legs, core, etc. against the strength of an isolated arm muscle or leg muscle. Your superpower would make such grappling moves moot, letting them recover from otherwise lost positions.

In my opinion, the best way to see what such a superpower would look like is to look at one of the internal martial arts, such as Tai Chi, Aikido, or Xing yi. The nature of what those martial arts try to accomplish causes them to tend to focus dramatically on ways to use the force of the whole body against an opponent whose structure is broken. It also means they tend to focus on things like the angular and linear momentums of the whole body. It doesn't matter how strong you are, if you try to apply an impulse (i.e. punch) when you can't control your own body's momentum, your punch will be ineffective. Instead of hurting the other person, it will rotate and/or shift you. This means that the focus of these martial arts will be similar to the focus of a martial art custom tailored to an individual who can apply maximum force in any direction.

You can see this effect in any matured martial art, but I find it is more easily seen in the internal arts because they choose to put themselves into positions which demonstrate their ability to remain unified when common sense would suggest they should be broken.

Answer 2

As other answers have indicated this ability would likely have very limited uses as the vast majority of movements we make are compound movements relying on many different muscle groups for balance and stability.
To further Cort Ammon's answer on the combat applications of this ability not only would it be impractical due to the fact that you need to ground yourself when throwing strikes against an opponent, you are still limited by Newton's third law of equal and opposite reactions. A 150lb man can only apply so much force to an opponent regardless of muscle distribution, a fact Hollywood and comic books tend to ignore with any super strength.
You also give the example of taking strength away from smooth muscle cells in favor of another action, I would consider this as a dangerous choice. Smooth muscle cells serve a much different function than skeletal muscle, instead of being used to mechanically move a body part smooth muscle is used to help push blood back through veins to the heart. Taking strength away from here would be not only dangerous but likely ineffective, smooth muscle does not require huge amounts of force to do its work and so would not provide as much of a strength boost and while taking away strength from here could lead to blood pooling in the limbs creating a backlog of cardio work that could severely hamper their recovery if not potentially cause cardiac problems.
As per your idea of positioning the body such that it relies more on skeletal structure than muscle activation to allow the strength from the lower body to be used elsewhere you can look at how persons with severe muscle atrophy move about to get an idea of this could apply to your character. Having a family friend with severe muscle atrophy I would say this idea is possible but don't expect them to be of any use in a combat situation while using this distribution as they would have almost no stability while delivering a strike and would be more likely to knock themselves over than deal damage to their opponent.

tl dr
Outside of your character using this in isolation exercises at a gym it's unlikely they would find the most use of this ability.

Answer 3

The spilling out your guts or losing balance are actually not too much of a problem if you consider the following points:

1. You're not using all your muscles at their full potential at all times. Leave just enough strenght everywhere and move only the power you have left over. This should be plenty for most extraordinary feets.
2. The transfer is instantatious. Just transfer the required power to have an effect for a couple of micro seconds leaving everything else in the mercy of gravity and structural strenght (skeleton, skin keeping things from moving, ...) and regain yourself right after.
3. Now that I think about it, it can also be much longer before you need to redistribute stuff back for stability. For example after jumping you're not really using any strenght in your legs while in the air until the moment you're landing again.

Taking the above points into consideration I could think of a couple of scenario's where even an average person with this ability could excel over a normal human:

You can take a punch

Since the muscle redestribution happens instinctively and instantaniously you can put it at exactly the place you are hit to counteract the entire force. For the one hitting you it'll feel like hitting a brick wall.

No more need for pliers

All you have to do is sit down so you don't need any muscle strenght in your legs. Redistribute it to the 2 fingers you're using to bend metal at will. The main advantage over using pliers is that you'll have a lot more control over your fingertips than someone using pliers. (To get a feel for how much more control you have over pliers try tying your shoelaces with 2 of those instead of using your hands directly).

Throwing stuff

You'll have to develop an entirely different technique on how to throw stuff but I can imagine records to be shattered in no time.
You start by holding something (a spear, a lead ball, discus, ...) loosely in your hand, maybe let it rest on your shoulder. Any muscle strenght you're not using for balance or holding the thing you first put into your legs and jump as hard as you can. Once your legs are fully stretched you move the muscle strenght to your torso to further increase the momentum with a strong twist. Finally you move all the muscle strenght to your throwing arm to really get it going.
After releasing the object you redistribute the muscle strenght again to regain balance and land like you normally would after a jump.

other olympic records

Same as for throwing stuf, once you develop your own specialised technique to maximise muscle use it'll be possible to jump really high, run really fast, ... Not going to list all possibilities here.

maximum bench pressing

There's 2 options here. Either use your full muscle strenght to break a record in how much weight you can push up at once. Or train normally (without your ability) without needing someone else standing there for safety if you can't lift up your final rep (just use some of your leg muscle to safely stash away the weights in the end).

self defense

Besides being able to take a punch, all you need to do is grab on to your attacker and squeeze really hard. Sure you might drop to the ground from losing all strenght in your legs for a second and consequently losing your balance, but the attacker's hand/arm/leg/neck will be completely crushed (unless if they have the same ability ofcourse).

attacking

assassination is easy. You just move your finger close enough to their neck in a swift motion and then use all your strenght in that finger to crush their throat in a simple flicking motion.

Answer 4

Your character does not necessarily need to transfer all strength from one part to another. Maybe take a bit from the core, legs, and the other arm to boost the punching arm. Additionally, your character can take the full strength from, say the left arm and move it to the right arm doing the punching or the leg that is doing the kicking.

What you would also want to consider is the strength of the tendons, muscle, and bone so that your character does not hurt him/herself going above his/her normal body limit.

Would be cool also if the character can transfer arm muscle strength and transfer it to the legs for enhanced jumping/kicking power.

You can also probably get some inspiration from My Hero Academia (https://en.wikipedia.org/wiki/My_Hero_Academia), an anime where the main character has a somewhat similar situation to yours. Not exactly the same but similar enough that you may get some good ideas there also.