Endurance. The game is 90 minutes long. Can you play at a top level for that long? The best way to improve your endurance is by running. You can run every day, if you’re really committed. You should start with at least 3 times a week. All it takes is 15 minutes. Over time you can increase the length of your runs and the speed at which you run.
Speed. To increase your speed you will have to focus on sprint training. Do a combination of Hill Sprints, and flat ground sprints (30, 50, and 100 yard variations). I would recommend at least twice a week. Focus on quick starting accelerations and once you get to top speed, hold it. Aim to go a little faster every time! Don’t make the mistake of neglecting any aspect of your physical fitness.
All of these areas work together. Improving one area will in turn improve others. Improving all areas of your physical fitness is going to take commitment, dedication, and hard work, but I know you can do it. Now get off the couch and put in some work! Actually, read the rest of this book first, then you can get to it.