WHAT IS ANAEROBIC EXERCISE?
We generally use oxygen as the fuel for our body’s movement. The term ‘aerobic’ literally means relating to, involving or requiring free oxygen. As we require more oxygen for fuel, we begin to breath move heavily to bring more oxygen in. At higher intensities of exercise our bodies lose the ability to use oxygen for fuel, and our muscles turn to other forms of energy. Anaerobic exercise is a physical effort intense enough to cause lactate to form, commonly referred to as ‘lactic acid’. This type of training is utilised by athletes to promote strength, speed, power and to build muscle mass.
There are 2 types of anaerobic metabolism, referred to as ATP-PC or Phosphagen system and the Glycolysis system:
The ATP-PC system is called ‘alactic anaerobic’ as it utilises creatine phosphate stored within the muscles as a quick source of adenosine tri-phosphate. You can think of this as a small store of readily available fuel which can be utilised by the muscles immediately for a max effort, but it’s burned through very quickly – eg: 10 seconds of all-out energy in a 100m sprint. This is the fuel we use during the ‘fight or flight’ response
The Glycolysis system converts glucose to ATP without using oxygen, and produces lactic acid as a by product. It provides for intense periods of exercise between 1-3 minutes. Build up of lactic acid is one of the key reasons muscles begin to fatigue until they eventually fail before recovery is required. In layman’s terms, Glycolysis is what creates that heavy/burning feeling in our muscles when we train hard which eventually forces us to stop. The efficiency of this system is improved through training, which is why people can work harder for longer without stopping as they become fitter.
Low intensity steady state training (LISS), such as walking, long slow runs, cycling and rowing uses the aerobic system. HIIT, like many team sports which mix short bursts of intensity and longer periods less strenuous movement, utilises a mix of aerobic and anaerobic training.