Skeletal Muscle Adaptation to Training

Question 1

Definition of resistance training

Answer 1

A systematic program of exercises involving the exertion of force against a load used to develop strength, power, and endurance of the muscular system.

Question 2

What is the definition of endurance?

Answer 2

ability of muscles to repeatedly develop and sustain contractions.

Question 3

What is the definition of strength?

Answer 3

Maximal force that a muscle or muscle group can generate once (1 rm).

Question 4

What are the principles of training?

Answer 4

Overload: The training effect occurs when muscle fibers are working at a level beyond which they are normally accustomed.

Specificity: structural and biochemical adaptations will only be observed in the muscle fibers utilized.

Response/reversibility: gains are lost when overload is removed.

Question 5

Basic understanding of structural/biochemical changes that occur with

Answer 5

Endurance training: increase in mitochondrial number, size, and oxidative enzyme activity. There is also an increase in capillary density and myoglobin. There is also a shift from type IIx to type IIa fibers to type I fibers but it is not permanent. Type IIa and type I experience a slight hypertrophy. there is a 2x increase in mitochondrial size after 5 weeks.

Resistance training: there is an increase in myofibril content (actin and myosin), an increase in intramuscular glycogen content and glycolytic enzymes, an increase in cross-sectional area of myofiber and whole muscle, and a shift from type IIx to type IIa.

Detraining: 50% of increased mitochondria was lost after 1 week of detraining and it took 4 weeks to regain adaptations

Question 6

What are the factors responsible for increases in whole muscle size (hypertrophy) with strength training (sarcoplasmic and myofibrillar hypertrophy, connective tissue):

Answer 6

Myofibrillar hypertrophy: an increase in myofibril content (actin and myosin)

Sarcoplasmic hypertrophy: an increase in non-myofibril content (glycogen and water)

Connective tissue: accumulation between fibers.

Question 7

Factors responsible for strength gains early in resistance/strength training (neural adaptations)

Answer 7

1. Recruitment of more motor units
2. Inhibition of golgi tendon organs
3. Recruitment of motor units at the same time
4. Increased motor unit firing rate

Question 8

Role of golgi tendon organ (GTO):

Answer 8

Protective reflex that ensures muscle does not over contract and cause structural damage. GTOs send information to the spinal cord via sensory neurons which in turn excite inhibitory neurons.