A few words on anaerobic exercise and interval training...
Anaerobic exercise is where the body is exercising at such a rate that the blood stream cannot supply oxygen to muscles fast enough.
Anaerobic exercise is essentially exercise without oxygen.
This happens during high intensity and cannot be held for long periods of time.
A product of your muscle exercising in an oxygen deprived environment is large amounts of lactic Acid. Lactic acid begins building up inside the muscle at a rate faster than it can be cleared creating muscle failure.
Anaerobic exercise refers to anaerobic muscle respiration and not respiration as a whole. The muscle still receives oxygen, just an insufficient supply to meet the demands of the activity.
What is anaerobic capacity?
Anaerobic capacity is referred to as anaerobic threshold or lactate threshold.
It refers to the point in the anaerobic exercise when the lactic acid starts to build up at a rate greater than it can be removed out of the muscle.
It is perhaps one of the best indicators of performance in athletes.
Traditionally an athlete with a higher VO2Max was considered fitter; however an athlete with a lower VO2Max but higher anaerobic threshold would be able to go further faster without experiencing muscle failure than an athlete with high VO2Max and a low anaerobic threshold.
Your anaerobic threshold can be improved by doing crap like this:
Three rounds, 21-15- and 9 reps, for time of: