Keep your mileage relatively low. The best time to develop neuromuscular coordination for (60-600)m speed is while one is under age 20. You have your twenties to log higher mileage. Trying to develop speed in one's later years is more than challenging. Even if you see yourself as a 5000m to Marathoner, no need for high mileage now. Sprint coordination drills, plyometrics and weight training now. You want to be able to free-weight squat, full range of motion at least x 2 your body weight. Eg. If you weigh 150 lbs., you want to be able to free-weight squat, full range of motion at least 300 pounds. If you're a future Marathoner, you will realize we all trade on our 1500m speed. Guys like Mohammed Farah and Rod Dixon race or raced Marathon app. 37 times their 1500m personal best or 1500m peak ability; guys like Al Salazar and Bill Rodgers were closer to racing Marathon 32 times 1500m P.B. or 1500m peak ability. Get fast now, mileage later.