S2 Lecture 1- Force, strength and power

Question 1

Resistance training in humans results in strength increases because of?

Answer 1

Muscle hypertrophy, muscle hyperplasia and neural adaptations

Question 2

When motor units contract more synchronously,

Answer 2

Increased strength and an improved rate of force development

Question 3

Explain fibre hypertrophy:

Answer 3

Resistance training causes protein metabolism. During exercise synthesis decreases and degradation increases, after exercise vice versa. Hormones such as testosterone facilitate fibre hypertrophy and things like synthetic anabolic steroids cause a large increase in muscle mass. Also can be a case of genetic such as mutations of myostatin in Belgian blue cows.

Question 4

Explain fibre hyperplasia:

Answer 4

Most hypertrophy is due to fibre hypertrophy. Fibre hyperplasia is the process of fibre splitting, each half grows to the size of the parent fibre which may also contribute to hypertrophy however there is very little evidence in humans.

Question 5

Explain motor unit recruitment:

Answer 5

Strength gain can occur without hypertrophy
-Normally motor units are recruited asynchronously
-Resistance training means more synchronous recruitment and increased strength with an improved rate of force development.

Question 6

Explain DOMS:

Answer 6

• 1-2 days after exercise
  -Muscle straining (can range from stiffness to severe, restrictive pain)
  -Major cause is eccentric contractions (not caused by increases in blood lactate concentrations)
  -Indicated by muscle enzymes in blood (e.g. creatine kinase) which suggest structural damage to the muscle membrane and an index of degree of muscle breakdown.