Physical exercise, particularly weight training, causes changes to the muscular system. Key changes include muscle hypertrophy, or an increase in muscle size and thickness. Chronic hypertrophy occurs with long-term weight training and causes an increase in total muscle protein and fiber size. Aerobic changes from endurance training include increases in myoglobin, mitochondria, and muscle enzyme levels, improving endurance. Anaerobic changes like increased ATP-PC and glycolytic capacity from sprint or weight training improve strength. Overall, weight training can reduce body fat and increase muscle mass without significantly changing total body weight.

1. Jean Melanie Vincent Haymo
Physical Education Teacher
MPhil Scholar Punjabi University
,Patiala
MPED L.N.I.P.E , Gwalior
EXERCISE
AND
MUSCLE

2. Physical exercise or training, particularly weight training, affects our
muscular system to a great extent. Many parameter of muscular
system get changed after weight training or endurance training.
HYPERTROPHY OF MUSCLES
– An increase in thickness or size of individual muscle fiber is called hypertrophy
of muscle. Two types of hypertrophy can occur: transient and chronic. Transient
hypertrophy is the pumping of the muscle that happens during a single exercise
bout. This is mainly due to the accumulation of fluid (edema) in the muscle.
– Transient hypertrophy last only for a short time. The fluid return to the blood
within hours after exercise.
– Chronic hypertrophy refers to the increase in muscle size that occurs with long
term weight training.

3. GAINS IN STRENGTH AND MUSCULAR ENDURANCE USUALLY DEPEND
ON THE SIZE OF MUSCLE FIBRE. THE WEIGHT TRAINING CAUSES THE
FOLLOWING EFFECTS:-
– Total amount of protein increases, which is essential for muscle growth.
– Due to resistance/weight training the size of muscle fiber increases.
– Capillary density per fiber also increases which cause more energy production.
– Amount of connective tissues increases.
– Blood supply in the muscles increases.
– Due to hypertrophy, muscular strength and muscular endurance increases
– Biochemical changes in the muscles

4. AEROBIC CHANGES (DUE TO ENDURANCE
TRAINING)
– Myoglobin content increases. Myoglobin is an oxygen binding pigment found in
muscle tissue which acts as an oxygen store and helps in diffusion of oxygen.
– Oxidation (breakdown) of fat and carbohydrates increases
– Number of mitochondria also increases thus more muscular energy is produced.
– Levels of activity of concentration of enzymes increases. Enzymes are protein
compound that speed up chemical reactions in the muscles.
– Amount of glycogen stores increases as a result of endurance training. It is essential
for energy production.
– An increase in the number of capillaries surrounding each muscle fiber. Capillary
allows greater exchange of gases, heat, wastes and nutrients.

5. ANAEROBIC CHANGES (DUE TO WEIGHT OR
SPRINT TRAINING)
– ATP-PC system capacity increases as a result more energy is produced. ATP-
PC system is an anaerobic energy system in which ATP is manufactured
when PC is breakdown.
– Glycolytic capacity also increases as a result of training.
– Capillary density per fiber also increases.
– Blood supply in the muscle increases.

6. BODY COMPOSITION CHANGES:-
For most individuals weight training produces little or no changes in total
body weight but the body composition changes considerably.
– There can be significant losses of relative and absolute body fat.
– Fat free weight or muscle mass increases.
– Changes in muscle and joint motion also take place.
– After training flexibility increases.
– After endurance training fat tissues losses.