Anaerobic Endurance

Anaerobic fitness or any training that involves intervals of intense activity and rest (or less intense activity) are very specific to playing soccer. This type of conditioning is also quite effective in burning calories and lowering your body fat.
Anaerobic activity is more intense (70-100% of your maximum heart rate) than aerobic but shorter in duration. Due to this, it is commonly referred to as quality training. Anaerobic activity is based on performing work while supplying the body with energy from stored sources such as glycogen. In this process, lactic acid is formed in the muscles thus causing you to feel fatigue or discomfort. Lactic acid buildup is the reason why anaerobic exercises cannot be long in duration and are usually segmented into intervals.
Anaerobic endurance refers to your ability to sustain intense activity and recover quicker. This is generally dependent upon your body's lactate tolerance and removal. Weightlifters, for example, try to keep the time between their sets of repetitions as short as possible. This way they are developing both their musculature and anaerobic endurance.

Muscle Endurance (Anaerobic fitness)

Anaerobic fitness accounts for your ability to recover quicker and consistently sprint at high speed. This is especially relevant to soccer. Throughout the course of a game, field players perform a number of maximum intensity sprints separated by periods of lower level activity.

-fartlek drills
-interval training drills

Related soccer fitness questions

How to consistently sprint at high speed for an entire soccer match