Transcript Sports and Protein Metabolism

Sports and Protein Metabolism
Dept. Exercise Health Science
National Taiwan College
Physical Education
Proteins
Proteins are one of many types of natural
polymers, and they are the most versatile
Make up about 20% or 200g/kg of muscle
tissue
Functions
As Enzymes
As Carriers and Receptors
As Regulators of Water Balance
As Biological Buffers
As Structural Elements and Structural Units
As Lubricants
In the Immune System
As Signaling Molecules
Structures
Overview of protein metabolism
Protein Turnover
whether the body is in a state of anabolism
(building up) or catabolism (breaking down),
also known as positive or negative Nitrogen
Balance
Is governed by hormonal factors, caloric intake
and availability of amino acids, particularly of
the nine ‘essential’ amino acids
Amino Acid Metabolism in Muscle
During Exercise
Amino acid can be broken down to produce
energy follows a unique catabolic pathway
Have to remove alpha-amino group
(deamination) to form ammonia
Effect of Exercise on Protein
Metabolism
Exercise changes the rates of protein synthesis
and the proteolysis in muscle
During hard resistance exercise , the rat of
protein synthesis will increase, provide a.a. in
contracting muscle
Moderate-intensity endurance exercise seem to
increase the rate of proteolysis, and net
decrease in muscle protein
Can reversed some hours after exercise
Prolonged running decreased the rate of
collagen synthesis and increase its rate of
breakdown in the Achilles tendon but synthesis
rate higher the baseline, makes connective
more resistant to mechanical stress of exercise
Plasma Amino Acid, Ammonis and Urea
Concentrations During Exercise
Total a.a. concent. In plasma is 3 to 4 mmol/L
Most abundant plasma a.a.; Glutamine and
Alanine
Not big affect the total a.a. exercise < 1 hr
Exercise > 2 hrs, plasma a.a. drops 30%
Moderate-intensity or hard exercise rises
plasma ammonia which relates to plasma
lactate concentration.
Plasma urea concentration. Increases by
exercise at 60% of VO2max
Not change during hard exercise as blood flow
to liver decrease; not enough blood to carry
urea out of hepatocytes
Effects of Training on Protein
Metabolism
Muscle hypertrophy by Resistance training
Cross-section area increase and maximal
strength increase
Can be measured few weeks after and
proceeds at a rate of 1% to 3 %
Muscle hypertrophy reach a plateau after 6
months of hard resistance training
Endurance training usually not accompanied
by muscle hypertrophy unless it use high
intensity
Endurance training increases in mitochondrial
proteins, leading to an increase in
mitochondrial number and size.
Protein supplementation
Improves exercise performance
Maintains strength during workouts
Increases muscle protein synthesis
Develops and maintains bone strength
Assists in muscle cell repair after exercise
Reduces inflammation, soreness and fatigue
Reduces length of recovery between training
Provides immune support following exercise
The Recommended Dietary Allowance (RDA)
for the average male and female adult is just
0.83 grams of protein per kilogram (2.2lbs)
of bodyweight. In a 70kg (154lb) individual
this equates to just 58 grams of protein per day
or about two chicken breasts worth
Competitive athletes, particularly those
involved in heavy weight training, may require
more protein. The recommendation for
strength and endurance athletes ranges from
1.2 to a maximum of 2.0 grams per
kilogram (1kg = 2.2lbs).
Research has shown that consuming more
protein than this serves no benefit and may be
harmful in the long term.
Protein should make up 10-15% of an athlete's
diet derived from fish, poultry, low fat milk
and lean red meat for example.
Discussion
From your point of view, which one amino
acid is of imperative important in young
weight lifter.
Can you plan a dietary project regarding
protein requirement to a distance-runner.
What is your protein consumption per day and
why. (hint: RDA)