The concept of strength could be explained as applying direct physical force onto something, or that's how it was in Type 4's case, at least. Just like how Type 5 boosted Agility, and Type 6 increased Durability, Type 4 focused on the Strength stat, greatly enhancing it.
Enhanced strength allowed for a lot more than just lifting heavy things. Stronger legs meant enhanced speed, and stronger arms meant enhanced punching power. Adding to that Force Amplification, Kinetic Boost, and Impact Amplification, a single punch could easily have the explosive power of a tank shell.
