Energy Systems

Alactic System

The anaerobic energy system that rapidly regenerates ATP through the breakdown of Creatine Phosphate in the sarcoplasm of muscle cells.

Lactic Acid System

The anaerobic energy system that resynthesizes ATP from glycogen through the process of Anaerobic Glycolysis, releasing 5% of energy from the glycogen molecule.

Aerobic System

The energy system that releases the remaining 95% of energy from the glycogen molecule by breaking down glucose in the mitochondria, dependent on the presence of oxygen.

Motor Unit

A group of muscle fibers innervated by a single motor neuron, which contracts when the neuron fires an electrical signal.

Action Potential

A wave of electrical activity that travels down a neuron, responsible for stimulating muscle contractions by releasing calcium ions from the sarcoplasmic reticulum.

Sliding Filament Theory

The theory that states the thick myosin filament in muscles slides past the thin-acting filament, causing muscle contraction.