Resources

“Any Torah scholar who is not as hard as iron, he is not a Torah scholar.” - Ta’anit 4a 

In his classic work, “Orot,” Rabbi Kook writes that the exercise of young Jews in Eretz Yisrael, in order to strengthen their bodies to become mighty sons to the nation, adds overall strength to the Jewish People, which enables the righteous to bring more Divine light into the world.

There are not a lot of Jewish specific strength programs out there, but "Who is wise? He who learns from every man." - Pirkei Avot 4:1

"Blessed is the LORD, my rock, who trains my hands for battle, my fingers for warfare" - Psalms 144:1

A form of self-defense and physical training, first developed by the Israeli army in the 1940s, based on the use of reflexive responses to threatening situations. 

"If someone comes to kill you, rise and kill him first." - Sanhedrin 72a

Guns can be a taboo subject for many, but for Jews living in places where they can arm themselves legally, they should, responsibly.  Get training.  Practice.  Learn how but when to use firearms properly, safely, and legally.