Name a muscle associated with ventilation.
_______ volume is air moved in and out of the
lungs during a normal breath.
_____ ventilation refers to air in the alveoli.
Name one condition in which ventilation becomes a
limiting factor in exercise.
What is one risk factor for lung disease?
“..The stronger you are, the harder you are to kill…”
- Rob Scott, Arkansas Strength & Conditioning …. & some other dude he was quoting….
1. What are the functions of the muscular system?
2. What is strength?
3. How does a muscle generate force?
4. How do we measure strength?
5. How do our muscles adapt to resistance training?
6. What are some training techniques that will enhance performance?
1. What are the functions of the muscular system?
2. What is strength?
Muscular
Endurance
Muscular
Fitness
Flexibility
Application of
max force
against an
external object
Muscular
Strength
Isotonic
Isometric
Isokinetic
Muscular
Strength
Concentric
Isotonic
Eccentric
Examples
Isometric
Contractions
Muscular
Strength
Isometric
Muscular
Strength
Concentric
Isokinetic
Eccentric
3. How does a muscle generate force?
1) Action Potential (AP) is generated in the
motor cortex
2) AP travels down the spinal cord via motor
neurons
a) The AP within a neuron is generated via an
electric signal (ion channels)
b) The AP that crosses from the axon of a
nerve to the dendrites of another neuron or
the t-tubule of a muscle fiber is a chemical
signal (requires neurotransmitter like AcetylCholine (ACh))
3) AP reaches the t-tubule of a muscle fiber
and generates contraction within the motor
unit.
• ONE motor neuron can
innervate MANY fibers
• ONE fiber can be innervated by
ONE motor neuron
• Fibers within motor unit will
possess similar characteristics
4) Axon releases Ach into synaptic cleft.
5) Ach floods receptors in t-tubule to
generate quick signal
a) The axon releases more Ach than can
possibly bind to t-tubule
b) Excess Ach is either reabsorbed into
the axon or is degraded by
acetylcholinesterase in the synaptic
cleft
6) This generates an AP down the ttubule (ion channel activation)
7) Changes in ion concentration cause
Ca++ to be released from the
sarcoplasmic reticulum (see next slide)
8) Ca++ binds to Troponin C on
Tropomyosin
a) This causes conformational shift,
revealing myosin binding sites on actin
b) Required for contraction
c) Ca++ is quickly reabsorbed by SR
after AP
7) Changes in ion concentration cause
Ca++ to be released from the
sarcoplasmic reticulum
T-Tubule
SR
a) Ion gated DHPR Channels bind ions
from AP.
b) This generates a conformational
change in the channel, activating
RyR1 channels that are physically
associated with DHPR.
c) This leads to broad activation of RyR1
channels (activated RyR1 that aren’t
in physical contact)
d) Activated RyR1 release Ca++ from SR
8) Intracellular Ca++ released from SR binds to Troponin C
a) Causes conformational change in tropomyosin, revealing myosin
binding sites on actin filament
9) Ca++ binding allows for cross-bridge formation and
subsequent contraction
10) Myosin heads with ADP+Pi bind
actin filaments
11) Release of Pi results in
powerstroke
12) ADP is released
13) ATP binds to myosin head which
allows the release of myosin from
actin
14) As long as Calcium remains
bound, the cycle restarts
Still unsure how the body generates
skeletal muscle contractions??
Check out the link below!!
https://www.youtube.com/watch?v=ousflrOzQHc
4. How do we measure strength?
5. How do our muscles adapt to resistance training?
6. What are some training techniques that will
enhance performance?
Overloading Stimulus
Original Glycogen Stores
Glycogen Depletion
Glycogen Stores
Glycogen Supercompensation
One Factor Theory
Overload
 Loading the body
beyond habitual level
to induce adaptation
Accommodation
Progression
Technique
Rep Scheme
(i.e., load and
reps)
Example of Squat progression…
BW Squat
Goblet
Squat
Focus: Technique
Technique
Endurance
Back
Squat
Front
Squat
Other (see below)
Hypertrophy
Strength
Power
•
Advantages of Technique:
• State of training
• Risk of injury
• Bilateral comparison : two limbs
• Ratio or % difference
• % deficit - % diff b/t higher and lower peak torque of the
two limbs divided by higher peak torque
•
Ipsilaterial comparison : opposing or reciprocal
muscles in same limb
https://bjsm.bmj.com/content/bjsports/early/2017/05/13/bjsports-2016096724.full.pdf