Effects of exercises on muscles and bone= dr gad

Effect of Prolonged Effect of Prolonged Exercise on Skeletal Exercise on Skeletal

MuscleMuscle

Gad El-Mawla Abd El-AzizProfessor of PhysiologyMansoura University

M.B., B.Ch. 1974 Mansoura University, Egypt.

M.Sc. (Physiology) 1980.

PhD. (Physiology) 1984.

Professor of Physiology (1994).

E-mail: [email protected]

Effects of exercise on sk. muscleEffects of exercise on sk. muscle

1- Increase muscle strength:1- Increase muscle strength: A muscle will only strengthen A muscle will only strengthen

when forced to operate beyond when forced to operate beyond its normal intensity (overload). its normal intensity (overload).

Overload can be progressed by Overload can be progressed by increasing the resistance, increasing the resistance, number of repetition and number of repetition and number of sets.number of sets.


2- Muscle endurance2- Muscle endurance ability of a skeletal muscle or group of ability of a skeletal muscle or group of

muscles to continue contracting over a muscles to continue contracting over a long period.long period.

ability to resist fatigue while holding a ability to resist fatigue while holding a position, carrying something for a long position, carrying something for a long period of time, or repeating a movement period of time, or repeating a movement without getting tired. without getting tired.

As you train for muscular endurance, the As you train for muscular endurance, the muscles adapt as a result of changes in muscles adapt as a result of changes in the slow-twitch fibres. The slow twitch the slow-twitch fibres. The slow twitch fibres have a high capacity to use oxygen.fibres have a high capacity to use oxygen.


2- Muscle2- Muscle enduranceendurance Lifting light weights with high Lifting light weights with high

number of repetitions will develop number of repetitions will develop muscle strength, and leads to muscle strength, and leads to Dynamic muscular endurance. Dynamic muscular endurance.

It is the muscle's ability to contract It is the muscle's ability to contract and relax repeatedly. and relax repeatedly.

An example of an exercise requiring An example of an exercise requiring dynamic endurance is the push-up. dynamic endurance is the push-up.


2- Muscle2- Muscle enduranceendurance Lifting heavy weights with low Lifting heavy weights with low

repetitions will develop muscle repetitions will develop muscle strength, and leads to strength, and leads to StaticStatic muscular endurance. muscular endurance.

It means the muscle's ability to It means the muscle's ability to remain contracted for a long period remain contracted for a long period of time. of time.

It is measured by the length of time It is measured by the length of time you can hold a body position.you can hold a body position.


3- Increase size of sk. 3- Increase size of sk. Ms. by:Ms. by:

I- Muscle hypertrophy:I- Muscle hypertrophy: The function of weight training is to The function of weight training is to

stimulate stimulate hypertrophy. . Weight training programs should Weight training programs should

therefore allow the muscles time to therefore allow the muscles time to repair and grow, otherwise repair and grow, otherwise overtraining can occur. can occur.

Muscle growth is normally completed Muscle growth is normally completed within 36 to 96 hours, depending upon within 36 to 96 hours, depending upon the intensity of the workout.the intensity of the workout.


3- Increase size of sk. Ms. 3- Increase size of sk. Ms. by:by:

I- Muscle hypertrophy:I- Muscle hypertrophy: Two different types of hypertrophy:Two different types of hypertrophy: Hypertrophy of myofibrils which occurs in Hypertrophy of myofibrils which occurs in

power lifters power lifters - contraction against 80–90% - contraction against 80–90% of the one repetition maximum for 2–8 of the one repetition maximum for 2–8 repetitions. repetitions.

Hypertrophy of sarcoplasm which occurs in Hypertrophy of sarcoplasm which occurs in body builders:body builders: - several repetitions (12 or - several repetitions (12 or more) against a sub-maximal load.more) against a sub-maximal load.


3- Increase3- Increase sizesize of of sksk. . MsMs. . byby::

II- Muscle hyperplasia:II- Muscle hyperplasia: Mechanism:Mechanism: A) large fibers can split into two or A) large fibers can split into two or

more smaller fibres (i.e. fibre splitting), more smaller fibres (i.e. fibre splitting), B) Satellite cells can be activated. B) Satellite cells can be activated.

Satellite cells are myogenic stem cells Satellite cells are myogenic stem cells which are involved in skeletal muscle which are involved in skeletal muscle regeneration. regeneration.


33- - IncreaseIncrease sizesize of sk. Ms. of sk. Ms. by:by:

II- Muscle hyperplasia:II- Muscle hyperplasia:

Mechanism:Mechanism: When you injure, stretch, or severely When you injure, stretch, or severely

exercise a muscle fiber, satellite cells are exercise a muscle fiber, satellite cells are activated. Satellite cells proliferate and activated. Satellite cells proliferate and give rise to new myoblastic cells (i.e. give rise to new myoblastic cells (i.e. immature muscle cells). immature muscle cells).

Myoblastic cells can either fuse with an Myoblastic cells can either fuse with an existing muscle fiber (i.e., hypertrophy) or existing muscle fiber (i.e., hypertrophy) or these myoblastic cells can fuse with each these myoblastic cells can fuse with each other to form a new fiber (i.e. hyperplasia).other to form a new fiber (i.e. hyperplasia).

Signs and symptoms of Signs and symptoms of excessive exercise and excessive exercise and

overtraining:overtraining: Decreased Decreased

performance performance

Loss of coordination Loss of coordination

Prolonged recovery Prolonged recovery

An elevated An elevated

morning heart rate morning heart rate

Headaches Headaches

Loss of appetiteLoss of appetite

Muscle soreness Muscle soreness or tenderness or tenderness

Irritability Irritability Depression Depression Low self esteem Low self esteem Exhaustion Exhaustion Exclusion of Exclusion of

other activities other activities

Muscle FatigueMuscle Fatigue Muscle fatigue is defined as failure to Muscle fatigue is defined as failure to

maintain the required force output. maintain the required force output. In prolonged exercise; for muscle In prolonged exercise; for muscle

contraction to continue, the muscle contraction to continue, the muscle requires carbohydrate. requires carbohydrate.

Depletion of muscle glycogen is Depletion of muscle glycogen is generally accepted as the primary generally accepted as the primary cause of fatigue.cause of fatigue.

Exercise can continue although at a Exercise can continue although at a reduced intensity provided the blood reduced intensity provided the blood glucose concentration is adequate. glucose concentration is adequate.

Mechanisms of muscular Mechanisms of muscular fatigue:fatigue:

a- Depletion of energy stores:a- Depletion of energy stores:

b- Accumulation of metabolitesb- Accumulation of metabolites

c- Acidosisc- Acidosis

d- Inorganic phosphated- Inorganic phosphate

e- Muscle ionic disturbancee- Muscle ionic disturbancef- Failure of excitation-contraction f- Failure of excitation-contraction

couplingcoupling

Effect of exerciseEffect of exercise

on structure and on structure and

functionfunction

of the bones and of the bones and

jointsjoints

Normal Bone remodelingNormal Bone remodeling

Normal bone remodeling process Normal bone remodeling process involves sequence of bone involves sequence of bone

reabsorption and formation.reabsorption and formation. Adults replace about 25% of Adults replace about 25% of

trabecular bone every 4 months trabecular bone every 4 months through reabsorption of old bone through reabsorption of old bone

by osteoclasts and formation of by osteoclasts and formation of new bone by osteoblasts.new bone by osteoblasts.

Bone MassBone Mass Bone mass peaks at age 20Bone mass peaks at age 20 Bone mass or density can be Bone mass or density can be

maintained between 20-40maintained between 20-40 Bones start to lose mass or density at Bones start to lose mass or density at

age 40 some athletes may keep bone age 40 some athletes may keep bone mass to age 50mass to age 50

Women may lose 50% or more, Men Women may lose 50% or more, Men may lose 25% or more at age of 50 may lose 25% or more at age of 50

Loss of bone mass is greatest between Loss of bone mass is greatest between 50-60. 50-60.

Exercise and boneExercise and bone Bone responds to exercise by becoming Bone responds to exercise by becoming

stronger. stronger. Young women and men who exercise Young women and men who exercise

regularly generally achieve greater peak regularly generally achieve greater peak bone mass (maximum bone density and bone mass (maximum bone density and strength) than those who do not. strength) than those who do not.

For most people, bone mass peaks For most people, bone mass peaks during the third decade of life. After that during the third decade of life. After that time, we can begin to lose bone. time, we can begin to lose bone.

Exercise and boneExercise and bone Women and men older than age 20 can help Women and men older than age 20 can help

prevent bone loss with regular exercise. prevent bone loss with regular exercise. Exercise strengthens and thickens the bone. Exercise strengthens and thickens the bone.

Without exercise, bones can become thin, Without exercise, bones can become thin, therefore the bone can't protect and support therefore the bone can't protect and support the body.the body.

Exercising allows us to maintain muscle Exercising allows us to maintain muscle strength, coordination, and balance, which strength, coordination, and balance, which in turn help to prevent falls and related in turn help to prevent falls and related fractures. fractures.

The best bone building The best bone building ExerciseExercise

The best exercise for your bones is The best exercise for your bones is

the weight-bearing kind, which the weight-bearing kind, which

forces you to work against gravity. forces you to work against gravity. Examples: lifting weights, walking, Examples: lifting weights, walking,

jogging, climbing stairs, and tennis. jogging, climbing stairs, and tennis.

Prevention of Prevention of Osteoporosis:Osteoporosis:

Balanced diet rich in CA & Balanced diet rich in CA & Vitamin D.Vitamin D.

A healthy lifestyle with no A healthy lifestyle with no smoking and no alcohol intake.smoking and no alcohol intake.

Bone density testing and Bone density testing and medication when appropriate. medication when appropriate.

Building strong bones during Building strong bones during childhood and adolescence.childhood and adolescence.

Weight-bearing exercises.Weight-bearing exercises.

Importance of Exercise Importance of Exercise to jointsto joints

Stronger bones and Ligaments.Stronger bones and Ligaments. Increase Thickness of the cartilage.Increase Thickness of the cartilage. Tendons become stronger.Tendons become stronger. Training makes the ligaments at Training makes the ligaments at

joints stronger. joints stronger. Regular stretching increases the Regular stretching increases the

range of movement at a joint. range of movement at a joint. Exercises strengthen the muscles Exercises strengthen the muscles

which act on the joins.which act on the joins.

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Effects of exercises on muscles and bone= dr gad