Are exercise intense enough to trigger lactic acid formation.
It is used in non-endurance sports to promote strength, speed and power and by body builders to build muscle mass.
Leads to improved performance in short duration, high intensity activities.
Exercises last from seconds to up to about 2 minutes.
Exercise activity lasting longer than two minutes has a large aerobic metabolic component.
Fast twitch muscle, versus slow twitch muscle, operates using anaerobic metabolic systems.
Recruitment of fast twitch muscle fibers leads to increased anaerobic energy expenditure.
Intense exercise lasting upwards of about four minutes may have a considerable anaerobic energy expenditure component.
Aerobic exercise includes lower intensity activities performed for longer periods of time.
There are two types of anaerobic energy systems: 1) the high energy phosphates, ATP adenosine triphosphate and CP creatine phosphate; and 2) anaerobic glycolysis.
High energy phosphates are stored in very limited quantities within muscle cells.
Anaerobic glycolysis exclusively uses glucose and glycogen as a fuel in the absence of oxygen or more specifically, when ATP is needed at rates that exceed those provided by aerobic metabolism.
The rapid glucose breakdown results in the formation of lactic acid.
Physical activities that last up to about thirty seconds rely primarily on the ATP-CP phosphate system.
Beyond this time limit both aerobic and anaerobic glycolytic metabolic systems begin to predominate.
The by-product of anaerobic glycolysis, lactate, is detrimental to muscle function at very high levels.
Elevated lactate levels occur within and around muscle cells during intense exercise that can lead muscular failure, known as fatigue.
The effectiveness of anaerobic activity can be improved through training.
Anaerobic exercise, such as weight lifting, builds additional muscle mass.
Muscle contributes to the fat-free mass of an individual and therefore effective results from anaerobic exercise will increase BMR.
Studies suggest that the resting metabolic rate of trained muscle is around 55kJ per kilogram, per day.
A substantial increase in muscle mass, say 5 kg, would make only a minor impact on BMR.