How the Nervous System Controls Your Muscles:

1
How the Nervous System Controls Your
Muscles Applications to Training Chad
Waterbury
2
A motor unit the motoneuron the muscle fibers
it innervates
motoneuron
3
Motoneuron sizes
Large motoneuron
Small motoneuron
4
single stimulus
4
repetitive stimuli
force
2
Called a SO unit Slow, Oxidative
2 4 6
60 min
time
Small MU
5
single stimulus
30
20
force
repetitive stimuli
10
2 4 6
50 min
time
Called a FR unit Fast, Fatigue-resistant
Medium MU
6
Called a FF Motor Unit Fast, Fatigable
single stimulus
repetitive stimuli
50
Large MU
force
2 4 6 15
time
7
large medium
small
FF FR
SO
force
single stimulus
repetitive stimuli
8
Size Principle
80
40
Largest MUs
Smallest MUs
9
Mechanisms of the Size Principle
Ohms Law V I x R
Small motoneuron I x Rsm Vm Large
motoneuron I x Rlg Vm
10
What Does this Science Demonstrate?
There exists a fixed, orderly recruitment of
motor units (Ohms Law). Smallest motor units
are recruited first, fatigued last. Largest
motor units are recruited last, fatigued first.
11
More Force More Strength
According to Vladimir Zatsiorsky
1. Train with maximal loads 2. Train with
submaximal loads as fast as possible 3. Train
with submaximal loads to failure
Which method do I think is least beneficial?
Why? (hint think of the Size Principle)