Question

Muscle contraction and fatigue prompt:

You are talking with a friend who has recently started an exercise regimen, and they comment that they are planning to quit because they experience muscle soreness following their workouts. In your communication assignment for this week explain why this occurs. You should focus on the molecular mechanism of muscle contraction and how muscles become fatigued. You should also discuss the ways muscles adapt to changing activity levels at the molecular level as you encourage them to increase their fitness level.

Answer 1

• The muscle soreness is occurs due to fatigue and the microscopic damage to the muscle fibers.
• Molecular muscle contraction occurs when the thin avtin and thick myosin filaments slide past each other.
• This process is driven by cross bridges which extend from the myosin filaments and cyclically interact with the actin filaments as ATP is hydrolysed.
• Fatigue happens due to the inability to maintain force generated by muscle.Fatigue occurs due to central and peripheral causes.
• Central causes include failure of transmission of information from motor cortex or other cortical areas to muscle.However,central defects for fatigue are rare.

1. Peripheral causes are impaired neuromuscular transmission,defect in generation of action potential in the muscle fiber,decreased excitation-contraction coupling,and decreased availability of O2 or glycogen to meet the energy requirement that impair the ability to generate force.
2. Fatigue developed during isometric exercise like weightlifting is different from that of isotonic exercise such as jogging.

• Appropriate training promotes exercise performance and impairs fatigability.
• The muscles adapt to changing activity by increasing in metabolism enormously that are meant to supply energy for repeated contraction and relaxation of the muscle.