Soccer is all about endurance. You're on the field for extended periods of time, and you must be able to explode to the ball, juke a defender and make a soaring kick at any time. (See Speed and Endurance for Soccer.)
During a typical 90-minute game, elite players run about 10 kilometers at 80 to 90% of their max. And they must do this while jumping, kicking, tackling, changing direction, sprinting and controlling the ball.
To maximize your game on the pitch, it's important to design a workout that builds your endurance along with other aspects of your athleticism.
The dynamic warm-up, usually 12 to 15 minutes, comprises mobility drills and movement preparation, getting you ready to perform at your best during your workout and reducing the risk of injury.
(Check out Start Every Soccer Practice With the 16-16 Workout).
Speed kills in soccer. So it should be a major focus of your off-season training. You need to work on several aspects, but the most important drill that you can do is the 10-Meter Dash.
Check out Essential Speed Drills For Soccer Players
Depending on the season, soccer players should perform two to four full-body workouts per week to build strength, power and muscular endurance. It's important to do full-body routines, because they more closely mimic how your muscles are used during a game. Also, make sure to do single-leg exercise to improve stability and eliminate muscle imbalances.
(Check out Strength Training for Soccer with Functional Circuit Workout.)
Balance training is critical for preventing ankle and knee injuries. Youth players in particular must do balance training to improve coordination and muscle control. Incorporate balance training into your workouts two to three times a week for 10 to 15 minutes at the end of each session.
Check out Soccer Balance Drills to Improve On-Field Performance.
Conditioning drills during the pre-season will help you get into game form. Do agility and quickness drills for 20 to 30 minutes at the end of a workout at the beginning of the week. Lower the time to 15 to 20 minutes during the season. Also, it's important to do repeated sprints. Sprint for 10 to 20 meters and walk back to the start.
Check out Soccer Conditioning to Produce Impact Players.
Stølen T, Chamari K, Castagna C, Wisløff U. "Physiology of soccer: an update." Sports Med. 2005;35(6):501-36.