Skeletal Muscle 3 Flashcards
What is an isometric contraction?
No muscle shortening, the load exceeds the tension created. Load weight force= force developed by muscle
What is an isotonic contraction? What are the two kinds?
Movement of the muscle, where there is a mismatch of load and tension.
Concentric and eccentric.
What is a concentric contraction?
Muscle shortening, where load weight force
What is eccentric contraction?
Muscle lengthening, load weight force > muscle force
What can eccentric contractions cause?
DOMS (delayed onset muscle soreness)
What is the current hypothesis on training?
That eccentric contraction will potentially make more sarcomeres in series with each other, so can operate at shorter lengths.
What is the length tension relationship?
That sarcomeres can create the most tension (force) at an optimal length (2.1/2.2 microns). Shortening this length will rapidly decrease the tension, and lengthening less so.
In terms of force and velocity, what happens during an isotonic contraction?
as the velocity increases, the force of contraction decreases, then as it decreases, force increases.
When is contraction most efficient?
1/3 of the maximum rate of shortening
How does creatine produce ATP?
creatine phosphate + ADP —( creatine kinase)—> creatine + ATP
What are type one muscle fibres?
Slow oxidative fibres:
- red in colour (myoglobin)
- high mitochondria
- present in postural muscles/ endurance atheletes
What are type 2a fibres?
Fast oxidative fibres:
- red in colour (myoglobin)
- oxidative and glycolytic metabolism
- high mitochondria count
- prone to fatigue
What are type 2b fibres?
Fast glycolytic fibres:
- white
- anaerobic metabolism
- good for short fast bursts
- resistance training –> type 2a
What is central muscle fatigue??
decreased CNS activation and/or decreased motor units recruited
What is peripheral muscle fatigue?
Decreased ca2+ sensitivity, slower x bridge formation
