It's battle powers, scouter from aliens... Who knows what is 2x stronger for them. Irl we wouldn't be able to give someone a number, like, hmm his strength is an 8. If you hear something like that it sounds more like a general rating, like "good, very good, but not perfect". Like the trend nowadays that elite fighters rate the other one from 1 to 10... It's just a basic how good and likely to win in a 1 vs 1 this fighter is.
There is a physical way to know how stronger someone's punch is than the other I guess. In DB there was a kind of punching machine in the 25th Budokai, there Mr. Satan would score more than double normal humans iirc. Way more than double actually since those other guys punching were pro fighters. Punching power = force or impulse generated when the punch lands.
F = ma (mass of the arm/fist times acceleration)
There is also momentum which is a relevant metric
Momentum = mass x velocity
Kinetic energy too, which is iirc mv²/2 ... Which would be like the energy delivered by the punch, in that case taking techniques, like proper stance, body rotation etc. into account.
Ngannou scored a ~ 129.2 units on a PowerKube, a device from the UFC PI that measures force, speed and energy, turning that into a number representative of his punching power. Ngannou's punching power can be Over 8,000!!!! Newtons of force depending on the set up. An average male's punching power, while it varies significantly, is estimated around 1,000 ~ 1,500 N ... With a kinetic energy of 120 ~ 160 Joules.
Let's assume the over 8,000!!! for Ngannou is like 9,000 N and the average male punching power is ~ 1,200 N. Roughly, 8x stronger. Going by kinetic energy instead, assuming Ngannou's would be ~ 1,200 Joules and the average male, like 150 Joules... Again, roughly 8x stronger.
Still, there are ways to measure the raw strength of a punch in which you'd find the difference shrinking down a lot between Ngannou and a normal human. Studies appear to show that fist velocities don't vary THAT much between trained fighters and untrained individuals... It's like, a trained pro fighter can generate a speed ranging around 9 m/s ~ 11m/s ... An untrained person, would generate, a very rough average since it's tough to have a precise range, 6 ~ 8 m/s (average male fist speed)... Small increase in speeds lead to a big difference since kinetic energy depends on v²... The speed difference isn't crazy though.
If both an untrained but physically fit man and Ngannou would throw a jab without proper technique, like, just throwing the jab without rotating the shoulders and hips, the raw force advantage of Ngannou would of course be bigger, but way lower than the above... More like, in the 1.5x ~ 2x stronger range. Basically, because the average man can generate decent force from their arms... The gap in technique and kinetic energy make the difference way bigger than if analysing under a simply raw strength lens.
There are also sophisticated ways that measure how hard muscles are firing. It's said that the strongest punchers in combat sports and an average strong man, may fire some muscles group roughly equally, during a jab. The triceps, for instance.
If looking at the mass of the arm alone, Ngannou's arm weigh, alone, ~ 6/6.5kg while a normal male's arm would weigh roughly 4/5 kg... The difference is more like 1.3/1.5x in mass alone. If both throw a punch at the same speed, the difference in energy would be ~ 1.5x as well.
So, it depends on how you look at it. If looking at the fist speed, the muscle force, the mass of the limbs in an isolated aspect... It might get you a << 2x difference in ""power"" between one of the strongest men and an average man. But when everything stacks together, taking into account the technical part of it, like body rotation, time, explosiveness alongside mass and speed, then the gap is like ~8x ....
