Depending on the function a muscle serves, it may need to generate maximum force rapidly, sustain activity for a long period, or contract and relax at a very rapid rate. Properties of muscles can facilitate these types of activities.
learning outcomes
You should be able to:
Explain the factors that determine how much force or tension is generated by a muscle.
Apply knowledge about muscle fiber types to explain how they contribute to performance abilities in aerobic versus anaerobic work.
In terms of the relationships between motor neurons and skeletal muscles, how can the nervous system control the amount of force generated by a muscle?
A skeletal muscle is made up of many muscle fibers. Each muscle fiber is innervated by one motor neuron constituting a motor unit, but one motor neuron may form synapses with multiple muscle fibers. The nervous system can alter the frequency of action potentials in one motor unit, and it can increase the number of motor units activated in the same muscle.
Why do postural muscles have a higher percentage of slow-
Postural muscles must remain continuously contracted for long periods of time, but they are not generally used for quick, powerful movements.
Apply knowledge about the three systems used by muscles as sources of ATP to explain observations about human physical performance.
The energy source for the sprint comes primarily from preformed ATP and creatine phosphate along with some contributions from glycolysis. These sources of ATP are rapidly mobilized. The longer 10-
Regardless of how much force a muscle can generate, how long it can sustain a workload, or how fast it can contract and relax, a muscle needs something to pull on; otherwise it would just be a lump of pulsating, quivering tissue. Let’s look now at how muscle and skeletal elements work together to produce movement.