If OP is true how does this work in terms of simple physics?
Force -which is what we are talking about in terms of physics not power- equals mass times acceleration, yes?
So if we are saying
1. the MASS is the same (the fist does not add any appreciable mass)
2. FORCE is the same in old age as it was always (the first point of the argument in this OP)
2. SPEED is reduced through aging (the second point of the argument in this OP)
my question then is HOW have we in our old age apparently reduced our speed of strike and yet maintained the acceleration of that strike that the FORCE upon impact is the same? how is my thinking incorrect in this? it has been a while and I am rusty over simple physics/engineering equations.. It must be because I am getting old haha. Can some one older and wiser (who has not yet lost all of their marbles like me) explain for me?? Thank you Jx.
To understand the answer to this, you have to get past the confusion many people have when they naively apply simple physics formulas formulas to complex biomechanical situations.
F = ma. Force = mass x acceleration. This is a fundamental concept in physics, and the one which seems most relevant to describing the impact of a strike. (There are other concepts, such as kinetic energy and momentum, which might be relevant - but let's keep it "simple" for now.)
Some people look at this equation and draw the conclusion that the speed of your punch is the most important determiner of its force. Other people draw the conclusion that your fist must actually be accelerating at the moment of impact to have any real force. These people are not understanding the application of the formula to real life.
Pop quiz: Master Ken throws a punch. At the moment before impact, his fist is travelling 30 meters per second and is still accelerating at 1 meter per second per second. His shoulder is traveling 10 meters per second and is no longer accelerating. His hips are traveling 3 meters per second and are actually slowing down at a rate of .3 meters per second per second. Master Ken weighs 90 kg and his fist weighs .5 kg. What is the force with which his punch impacts the target?
It's a trick question. There is not sufficient information given to answer the query. Even if I gave you the velocity, acceleration, and mass of each part of Master Ken's body, you still wouldn't have enough information.
For one thing, the a in f=ma has nothing to do with the forward acceleration of the punch before impact. To make that point clearer, imagine being struck by a car travelling 40 kph whose driver has already applied the brakes. The car is already slowing down when it hits you, but it still applies plenty of force by accelerating your body. (You could also view it as your body applying force to further decelerate the car.)
How do you calculate the force of the punch then? It's complicated. If your punch has poor alignment and your arm is floppy, then it won't transmit much force even if the fist is travelling very quickly. (Imagine the difference between being hit by a 1500 kg auto traveling at 40 kph and being hit by a 1500 kg cube of Jello travelling at 40 kph. Which are you more likely to survive?) Structure and body alignment make a huge difference, but there aren't any simple physics equations to describe those. Another factor is the movement of the target. Great strikers cause collisions, so that the target is moving into the strike at the moment of impact, adding more force.
Bottom line - an aged boxer will probably propel his punching fist at a slower speed than an young boxer of the same size and skill. This will reduce the force of the punch. However, that hand speed is a relatively small piece of the final result compared to technique and body alignment, so the old guy can still retain knockout power.