Power is how quickly you can release strength. It's not technique or skill. You have some 900lbs squatters that have terrible vertical leap because while they have strength but not power. Olympic lifting should be called power lifting and power lifting should be called strength lifting. One of the most important commodities in sport is power. When you punch hard, sprint fast, jump high, tackle an opponent, or kick hard it is a demonstration of power.
Rocky was strong as hell. In addition he had the related athletic commodity of incredible power.