Never judge another unless you have worn their shoes. This is done only by hard work, and cannot be reached by taking short cuts. Muscle fibers grow only when effort is exerted on them. A short cut is usually the quickest way to someplace you do not want to be. Strength gives you stamina to excel beyond the average ability for extended periods of time.
Great players have it and can sustain it.
The team that plays as individuals will always fail against the team that players together. Time is something you must give yourself. Each person needs time to grow, because a house is only as strong as it's foundation. A well-laid foundation takes time to build. Build a house of stone not sand.