Isokinetic
- Muscle contraction at a constant velocity.
- For example, pushing an object that cannot be moved.
Agonists
- Muscle performing a particular action.
Antagonists
- Muscles that act in opposition to the movement generated by the agonists.
- Responsible for returning a limb to its initial position.
- Reciprocal Inhibition (forced relaxation).
- Inhibited from contracting due to tight agonists.
Antagonistic Muscle Groups
- Pectorals/latissimus dorsi.
- Anterior deltoids/posterior deltoids.
- Left and right external obliques.
- Quadriceps/hamstrings.
- Biceps/triceps.
- Forearm flexors/extensors.
Synergists
- Smaller muscles providing assistance to the larger working muscle groups.
Stabilizers
- Muscles providing stability in order for the agonist to perform.
The individual fiber is stimulated to contract by a branch of the neuron called an axon. If
you could isolate and cut a cross section of an individual skeletal muscle cell fiber and look inside,
you would see that it consists of several components, each having a specific function. Your
training will be increase in productivity when you understand how to individually and intelligently
affect the cell function.
Connective Tissue and Blood Supply
The epimysium surrounds the entire muscle group with a sheath of connective, fibrous,
and elastic tissue. The sheath of connective tissue surrounding a bundle of muscles, or motor
unit, is called the perimysium, and the connective tissue surrounding each muscle cell fiber is the
endomysium. These different fibers have differing cardiovascular “support systems.” Microscopic
capillaries extend throughout intramuscular areas surrounding all of these muscle tissue fibers.
The white, fast twitch muscle fibers have very few capillaries, and in the absence of this nutrient
rich blood supply, they cannot function for very long periods, but are extremely strong. The red,
fast twitch muscle fibers have a greater number of capillaries, and can, therefore, outlast the
white, fast twitch fibers, but are not nearly as strong. The red, slow twitch muscle fibers have a
tremendous number of capillaries, allowing for long-term sustained activity, however, with very
little strength.