Energy systems. PHYSIOLOGICAL REQUIREMENTS OF PHYSICAL ACTIVITY. Foods Fuel and Energy Systems.
A Maria Sharapova serve takes 1-2 seconds to perform. It’s fast & explosive. She might do this hundreds of time over a game. Plus she has to run fwd, bkwd and sideways for 1-2 hours. Her Muscles requires ENERGY to do this.
Where does this energy come from?
1. CARBOHYDRATES (Glycogen)
Carbohydrates are stored as Glycogen in Muscle & Liver
CHO is the body’s preferred fuel during Exercise – breaks down easily, uses little oxygen
Protein is stored as MUSCLE and AMINO ACIDS around the body.
5-10% contribution to endurance events: Mainly used for growth/repair
This food must be converted into a chemical compound called ATP
WithoutATP, Muscles cannot contract
Resynthesises the ADP back to ATP
The type of energy system used and the interplay between them depends on the frequency, duration, intensity of the activity and fitness levels of the individual.
LACTIC ACID SYSTEM
30 + SEC- 2MINS
CP instantly available, but runs out quickly
Uses stores of CP (Creatine Phosphate) to REMAKE ATP
Used for high intensity Jumps, Throws, Sprints
Only have 10 seconds of CP in muscles
If activity lasts longer than 10 sec, ATP must be REMADE by some other means…..
Body uses stored fuel of GLYCOGEN to REMAKE ATP
Need Oxygen to do this properly
About 2-3 hours of glycogen stored in body.
Downside – by-product called Lactate. Hydrogen Ions also released which inhibit muscle contraction
Happens because of lack of enough Oxygen to break down Glycogen
400m run, 800m at high intensity
Plenty of Oxygen available to remake ATP . So no LA or H+ is accumulated
Used in longer, sub-max activities. Long run, swim, cycle.
Like the LA system, the Aerobic uses Glycogen to remake ATP.
Oxygen supply meets demand
We use this system at REST (Now!) – except we burn…
Will keep suppling ATP for as long as Fitness levels allow
Any rest, short OR Long, CP is being replenished, so we can ‘sprint’ again.
BUT, need 3 minutes rest to get all CP back!
Any Lactate and Hydrogen Ions are removed from muscles & blood stream too.
All 3 turn on at once no matter what the activity.
However, depending on intensity and duration of the activity, ONE system will contribute more than the other TWO.
The 3 Energy Systems are not like TRAFFIC LIGHTS. One does not switch off and another goes on.