SECURING ENERGY FOR SPORTS PERFORMANCE
David Zahradník, PhD.
Projekt: Zvyšování jazykových kompetencí pracovníků FSpS MU a inovace výuky v oblasti
kinantropologie, reg.č.: CZ.1.07/2.2.00/15.0199

Muscle fiber
Tendon
Muscle belly
Fasciculus
Myofibril

Type of muscle fibers
Key criteria for the classification of types of muscle fibers:
1. Ability to supply sufficient energy for muscle contraction
2. Ability to resist fatigue
We distinguish:
Red
White
or
Type I.
Type IIa, IIx

Basis characteristics
Type I (red)
Resist fatigue
High capacity for aerobic metabolism
Unsuitable for activities with high loading rate
Low anaerobic performance
Type II (white)
fast defatigable
High capacity for anaerobic metabolism
Suitable for activities with high loading rate
Low anaerobic performance
slow
fast

Fiber types
Characteristic
Type I
Type IIa
Type IIx
Motor neuron size
Small
Large
Large
Nerve conduction velocity
Slow
Fast
Fast
Contraction speed
Slow
Fast
Fast
Relaxation speed
Slow
Fast
Fast
Fatigue resistance
High
Intermediate/Low
Low
Force production
Low
Intermediate
High
Power output
Low
Intermediate/High
High
Endurance
High
Intermediate/Low
Low
Aerobic enzyme content
High
Intermediate/Low
Low
Anaerobic enzyme content
Low
High
High
Capillary density
High
Intermediate
Low
Myoglobin content
High
Low
Low
Mitochondria size / density
High
Intermediate
Low
Fiber diameter
Small
Intermediate
Large
Color
Red
White/red
White
slow
fast

Event
Type I
Type II
100 m sprint
Low
High
800 m run
High
High
Marathon
High
Low
Olympic weightlifting
Low
High
Soccer, hockey
High
High
Basketball
Low
High
Distance cycling
High
Low
Baseball pitcher
Low
High
Boxing
High
High
Cross-country skiing
High
Low
Tennis
High
High
The relative proportion of different types of muscle fibers in different sports

Bioenergetics
Essential terminology:
Bioenergetics or the flow of energy in a biological system, concerns primarily the conversion of
macronutrients-carbohydrates, proteins and fats, which contain chemical energy.
Energy emerges with the decomposition of high-energy bonds in such macronutrients which release
energy needed to carry out mechanic work.
Catabolism is the breakdown of large molecules into smaller molecules, associated with the release
of energy (e.g. breakdown of glycogen into glucose).
Anabolism is opposite of catabolism. It is the synthesis of larger molecules from smaller molecules
(e.g. synthesis of proteins from amino acids).

Adenosine triphosphate (ATP)
Adenine
Triphoshate
Adenosine
Ribose
High-energy bonds
The only possible,, fuel,, of skeletal muscle

Flow of energy in a biological system



intensity
low
high
How?
aerobic
anaerobic
Where?
Mitochondria
Sarcoplasm
substrate
Carbohydrates
Fats
(Proteins)
Carbohydrates
Energy system
Slow glycolysis
Oxidative system
Fast glycolysis
ATP-CP system
(phosphagen)

Energy systems
Phosphagen (ATP-CP)
Fast glycolysis (LA)
Oxidative system (O2)
Slow glycolysis (O2)*




Phosphagen system (ATP-CP)
The phosphagen system provides ATP primarily for short-term, high-intensity activities (e.g.,
resistance training and sprinting) and is active at the start of all exercise regardless of
intensity.

Glycolysis
Glycolysis is the breakdowns of carbohydrates-either glycogen stored in the muscle and in the liver
or glucose delivered in the blood-to resynthesize ATP.
Pyruvate is the end result of glycolysis, may proceed in one of two directions:
1. Pyruvate can be converted to lactate
2. Pyruvate can be shuttled into the mitochondria

Oxidative system
The oxidative system, the primary source of ATP at rest and during low-intensity activities, uses
primarily carbohydrates and fats as substrates.
Following the onset of activity, as the intensity of exercise increases, there is a shift in
substrate preference from fats to carbohydrates.

Creation of energy, capacity
Creating ATP through the above energy systems differs in its ability to supply energy for
activities of different intensity and duration.
In general, there is an inverse relationship between a given energy system’s maximum rate of ATP
production (i.e., ATP produced per unit of time) and the total amount of ATP it is capable of
producing over a long time.
As a result, the phosphagen energy system primarily supplies ATP for high-intensity activities of
short duration (e.g., 100 m dash), the glycolytic system for moderate to high intensity activities
of short to medium duration (e.g., 400m dash), and the oxidative system for low intensity
activities of long duration (e.g., marathon).
The extend to which each of the three energy system contributes to ATP production depends primarily
on the intensity of muscular activity and secondarily on duration. At no time, during either
exercise or rest does any single energy system provide the complete supply of energy.

Effect of Event Duration and Intensity on Primary Energy System Used
Duration of event
Intensity of event
Primary energy system(s)
0-6 seconds
Extremely high
Phosphagen
6-30 seconds
Very high
Phosphagen and fast glycolysis
30 second to 2 minutes
High
Fast glycolysis
2-3 minutes
Moderate
Fast glycolysis and oxidative system
>3 minutes
Low
Oxidative system

Rankings of Rate and Capacity of ATP Production
Note: 1 = fastest/greatest; 5 = slowest/least
System
Rate of ATP production
Capacity of ATP production
Phosphagen
1
5
Fast glycolysis
2
4
Slow glycolysis
3
3
Oxidation of carbohydrates
4
2
Oxidation of fats and proteins
5
1

Thank you for your attention