How do you train to hit harder? Do squats and bigger muscles help?

[Warrior Scholar]

The ultimate guide to hitting harder

I have done some research and based on what I have read, most of the power of a punch comes not from the fist or arms, but from the power generated in the legs. Is this true or just a myth?
That would explain why boxers like Tyson hit so hard because they had rock hard legs like tree trunks

Other training to punch harder - speed bag, shadow boxing, squats, explosive training, HIIT cardio

Am I missing anything else? What other factors in training can improve your punching power?

Golf driving range

[Warrior Scholar]

for the straight power shots

[Kitsune]

"Simple" physics basically: force = mass x speed
So different factors play a role. Arms/technique are important for speed, a proper technique is required to get all your mass involved (legs, hips, shoulders). This means legs are important both for speed and to transfer your mass.

I would work first on a proper technique (mitts/heavy bag/shadow boxing etc. Training your legs doesn't automatically improve your power (in case of improper technique).

See also Rebounds post about proper technique...Technique is everything and often underestimated.

[Marchegiano]

Kinematic chains.