Boxing

Theoretically, as few as just one. Extend your arm with your tricep and your hand flops forward into your opponent's face. Mission accomplished.

For an actual punch as hard as you can with good form, all muscles in your hand, your forearm to twist your wrist, tricep to extend your arm out all the way, Bicep to bring it back to guard, all areas of the deltoid, and a little bit of you pecs where the tendon connects to the front of the deltoid, Also your lats to keep your arm up and lats for full extension, because the are connected to traps, and deltoid, your abdominal and obliques to twist your body with the punch for more power, and also your hip flexors, all leg muscles (whether you twist rear leg or not for power) to keep you standing and balance after the punch so you don't fall over.

Joe Lewis and Max Schmeling came together twice with Schmeling winning the first bout by KO in round 12 and Louis winning the second by TKO in round 1.

The circumstances leading up to their first fight were more boxing achievement / ranking than political. Schmeling had won the Heavyweight title in 1930 by disqualification from Jack Sharkey. However, after only one defense, he lost the title back to Sharkey in 1932.

By the time Louis and Schmeling met for the first match in 1936, James Braddock held the title and Schmeling was ranked as the #2 contender, in line for a shot at the title held by Braddock. However, because Louis was so revered in the US, few (if any) truly believed that Schmeling would be a real threat to Louis. Maybe because Louis knew this, or maybe because he felt Schmeling was nonthreatening himself, he did not prepare for the fight with the intensity one would expect when readying to face the #2 contender for the Heavyweight Championship.

Before the fight Schmeling said, quoting loosely, "I see something." Though he would not tell what it was that he saw, he believed it to be a flaw in the technique of Louis that he could exploit. Obviously, watching the fight footage, he was right!

When the fight was underway, Schmeling was able to hit Louis with the straight right cross way too often. Schmeling's right became an offensive weapon for which Louis could find no good defensive answer.

Finally, in round 12, Schmeling landed a right cross to the body followed by another to the chin, sending Louis down and out, leaving fans stunned.

However, Louis trained for revenge with a vigor and, in 1938, stepped into the ring with Schmeling for a second time. This time Louis was ready! He won the rematch in the very first round by technical knockout after sending Schmeling to the canvas 3 times!

Eventually, the two formed a friendship outside of the ring that lasted right up until Louis' death in 1981, where Schmeling was a pallbearer at Louis' funeral.

Seems like Two whole questions. I'd suggest one ask 1st where can they get Kick Boxing Classes /question, alone. But, this may or may not be useful to all young boys, and girls. Otis Grant in Montreal, Canada has an Open world Webb site and he owns a boxing gym in Montreal. I've seen questions from young persons posted there, in past.