Resistance exercise Flashcards
Define resistance exercise
any exercise that causes the muscle to contract against an external resistance
How are muscles structured?
myofibrils –> muscle fibre –> muscle fascicle –> muscle
What 2 ways does muscle CSA increase?
1. hypertrophy McCall et al (1996) showed sig increases in hypertrophy in college men after 12 weeks resistance training 2. hyperplasia
What is the mechanism of hypertrophy?
myofibril splitting, increases CSA, allowing more cross bridges to form
When does hyperplasia occur?
up until 60-70% of gestation, unlikely after that.
Link between strength athletes and muscle fibre no. not conclusive as casual relationship may be in either direction.
What is a motor unit?
a motor neuron and the muscle fibres it innervates
What is Henneman’s size principle?
fibres are recruited in order of size as more force is required.
What are 3 neural adaptations to resistance training?
- motor unit recruitment pattern (efficiency)
- increased innervation ratio (morphological)
- frequency of action potential firing (summation)
all three adaptations increase force per unit of mCSA, explaining why people can see rapid strength increases without increased mCSA
- (Folland & Williams, 2007)
Does fibre type proportion vary between athletes?
Yas,
thought to be mainly down to genetics
How long do fast and slow twitch fibres take to reach peak tension?
Fast = 50ms Slow = 110ms
Does fibre type change with resistance training?
Nope,
however, % of fiber area does change, supporting hypertrophy occurrence.
- (Costill et al, 1979)
What do cross innervation trials tell us?
Nerve dictates fibre type
What are satellite cells?
‘dormant stem cells’
Describe the process satellite cells go through when exposed to an anabolic stimulus (mechanical or chemical)
.cells activate, proliferate and differentiate
.some cells form more satellite cells
.some cells attracted to the damaged fibres via chemotaxis
.cells fuse to the damaged myofiber (hypertrophy), regenerating it.
Does load impact strength and mass gainzzzzzz?
No, as long as you work to failure
Both high and low loads are effective in increasing mass and strength.
Strong bias towards heavy load, especially for strength
- (Schoenfeld et al, 2016)