There are four core elements to fitness; Strength, Stamina, Endurance, and Power & Speed. To be a monster, you need to be competent in all four aspects, along with flexibility, joint mobility, and core stability.
Strength is the ability to do hard, heavy work.
Strength is the foundation of fitness and is typically represented and trained through the slow lifts; Squat, deadliest, press, bench press, and the squat clean and clean and press. Strength is measured relative to bodyweight.
Stamina is overcoming resistance repetitively with efficiency over time.
Stamina or work capacity is carrying heavy stuff farther or doing more work in less time. It is typically represented and trained through circuit (Crossfit style) workouts or through repeating an exercise for a set amount of time, particularly bodyweight exercises such as a military PT test.
Endurance is the ability to go long and slow over distance.
Endurance or long slow distance is aerobic exercise such as running, cycling, rowing, and swimming, across the water, air, and land.
Power & speed is the ability to overcome resistance explosively.
Power is typically represented and trained through short bursts of anaerobic exercise, including Olympic lifting and sprints. Power is the outcome of being competent in the other three core elements of fitness. Increasing your speed is to minimise the cycle of repetition.