crossfit energy system
TRANSCRIPT
Energy
Systems
&
Muscle Fibers
type
Energy Systems
Overview
Ma
xim
um
Ra
te o
f En
erg
y
Pro
du
ctio
n
Maximum Duration of Energy Production
Old School …
Aerobic Anaerobic
200m 11% 89%400m 23% 77%800m 35% 65%1500m 45% 55%
*800m/1500m = Fran/Helen WOD’s
New School…
Aerobic Anaerobic
200m 29% 71%400m 43% 57%800m 66% 34%1500m 84% 16%
*800m/1500m = Fran/Helen WOD’s
% Aerobic Contribution
0
20
40
60
80
100
200m 400m 800m 1500m
New
Old
% Anaerobic Contribution
0
20
40
60
80
100
200m 400m 800m 1500m
New
Old
When does the Switch Occur?
15-30 Seconds
Muscle Fiber
Overview
Muscle Fibers Best to think of Muscle Fiber type as a Continuum
• LEFT = Pure Slow Twitch
• RIGHT = Pure Fast Twitch
• Middle = Many Blends and Variations
Characteristic of Fiber Types
Slow Twitch
-Recruitment is Slow
-Relaxation time is Slow
-Force = Low
-Fatigue Resistant = High
- Cell = Aerobic Enzymes
Fast Twitch
-Recruitment is Fast
-Relaxation time is Fast
-Force = High
-Fatigue Resistant = Low
- Cell = Anaerobic Enzymes
Athlete Examples
Slow Twitch Fast Twitch
Middle?
How do we know what Fibers
we are Training???
Determining Factor = Force
Less Force =
More Slow Twitch Fibers
More Force = More
Fast Twitch Fibers
How does this Relate to
Crossfit?
The Crossfit Problem…
Moderate to High Force
application over a broad
amount of time.
Endurance events like
Running or Cycling
when an athlete is
tired he/she can’t kick.
(Recruit FT Fibers)
Crossfit makes the
“tired” athlete Recruit
(FT) Fibers whether
they want to or not. At
the expense of time.
Considerations for Untrained
Novice Crossfit Athletes…
Body weight exercises could recruit
(FT) fibers which will make them go
anaerobic quicker.
-In this case, Athlete will need more
time to recover between WOD’s.
(Max Effort)
Fast explosive movements are an injury
precaution because athlete have not
established neural pathways to recruit the
necessary (FT) fibers.
- Remember (ST) Relaxation Rate
- Exercises Examples
- Down Hill Sprinting
- Eccentric/Rebounding Plyo’s
Weak Athletes could still be “Aerobic
Giants” a.k.a. have great Engines!- Structurally they are too weak to exude the
power to show you!
- Remember “Structural changes happen
slower than metabolic.”
Must haves for the Elite Crossfit
Athlete…
- Absolute Strength
- Very High Percent of Dynamic to Absolute
Strength (FT Fibers)
- Great Aerobic Capacity with out
sacrificing Strength (Enzymatic Fight)
- High Level of Skill (Technique)
- Great Neural Pathways (Recruiting FT Fibers)
The End