adaptations of the neuromuscular system to exercise Flashcards
why does a rapid gain in strength occur when starting resistance training?
neural adaptations
when does hypertrophy begin?
8-10 weeks after starting resistance training
what are the mechanisms behind gain of strength due to neural changes?
changes of motor unit recruitment and increase in motor unit recruitment
what changes to motor neurone recruitment occur?
change from asynchronous recruitment to synchronous recruitment. this facilitates contraction, produces more forceful contraction, increases rate of force development and increases capability to exert steady forces
how does motor unit recruitment increase?
- increased neural drive during maximal contraction
- increased frequency of neural discharge
what are the mechanisms of muscle strength gain?
- decreasing inhibitory impulses
- reduced coactivation of antagonists and agonists
what is the role of the golgi tendon organs?
inhibit muscle contraction if tendon tension is too high
what type of training is hypertrophy maximised by?
high velocity eccentric training, disrupts sarcomere Z-lines
what is chronic hypertrophy?
increase in the size of individual muscle fibres
what occurs in hypertrophy?
- development of more myofibrils - allows greater cross bridge cycling and more generated force
- proliferation of cell types involved in connective tissue
why are muscle cells multi-nucleated?
nuclei only support a limited cell volume, and muscle cells are very large
what is the source of new nuclei?
fusion of myogenic stem cells with muscle fibres
what is meant by the concept of ‘muscle memory’?
trained athletes can recover strength more quickly than novice exercisers - retention of myonuclei could be the cause of this
what is the effect of exercise on protein synthesis?
during exercise, synthesis decreases and degradation increases. after exercise, synthesis increases and degradation decreases
what is mTOR?
a serine/threonine kinase that receives input and regulates the amount of protein synthesis that occurs. it is activated n response to amino acids such as leucine or arginine
