This document discusses different types of skeletal muscles and exercises. It describes slow-twitch and fast-twitch muscle fibers, and the characteristics of each. It also outlines different types of exercises including aerobic, flexibility, resistance, and classifications based on intensity. The document provides detailed information on muscle fiber composition and how it relates to endurance versus rapid movement capabilities. It explains how different exercise types impact cardiovascular health, strength, and joint protection.

1. ‫آية‬ ‫البقرة‬
32

3. Gad El-Mawla Abd El-Aziz
Professor of Physiology
Mansoura University
M.B., B.Ch. 1974 Mansoura University, Egypt.
M.Sc. (Physiology) 1980.
PhD. (Physiology) 1984.
Professor of Physiology (1994).
E-mail: elmawla@hotmail.com

4. Types of Skeletal
Muscles
and
Types of Exercise.

5. Types of muscles

6. Skeletal Muscles

7. Connective tissue covering

8. Functional histology of Sk. Ms.

9. Ultra-structure of myofibers

10. Ultra-structure of myofibers

11. Type of Sk. Ms. muscle fibers

12. Slow (red) muscle fibers (type I)
 These muscle are adapted for long slow
contractions which maintain the body posture
(support the body against gravity) e.g. back
muscles, soleus muscle etc.
 These muscles have a relatively longer latent
period, contract slowly and relax slowly.
 The duration of the simple muscle twitch is
more than 100 m. sec

13. Duration of the simple muscle twitch

14. Slow (red) muscle fibers (type I)
 These muscles are red because they contain the
respiratory pigment myoglobin which facilitates the
uptake of O2 from the blood stream.
 These muscles are composed of muscle fibers which
are of small diameter, contain much mitochondria
and high concentration of mitochondrial enzymes
(aerobic oxidation).
 They are surrounded by numerous blood capillaries
(red fibers). Glycolytic activity is less well developed
(anaerobic is secondary) and has a low activity of
ATPase.

15. Slow (red) muscle fibers (type I)
 They are suited for prolonged aerobic
exercises.
 Slow (red) muscles do not show fatigue
because:
- slowly contracting i.e. use ATP at a slow
rate.
- richly supplied with blood which is able to
supple them with O2 and nutrients.
- adapted to use aerobic oxidation which
provides much energy (38 ATP molecules for
each molecule of glucose).

16. Fast (pale) muscle fibers (type II)
 adapted for fine and rapid movements e.g. extra
ocular muscles.
 have a short latent period, contract rapidly and
relax rapidly. The duration of the simple muscle
twitch is less than 10 m. sec.
 composed of muscle fibers which are larger in size
and contain much more sarcoplasmic reticulum for
rapid Ca++ release and glycogen granules.
 contain well developed glycolytic system for energy
transfer, and high activity of myosin ATPase.
 generate energy rapidly for forceful contraction.

17. Fast (pale) muscle fibers (type II)
 The myoglobin is absent and there are few
blood capillaries (pale fibers) and few
mitochondria.
 Fast (pale) muscles are adapted to use
anaerobic glycolysis.
 So, these muscles are able to produce ATP
rapidly and at high rates but quickly fatigued
once their glycogen stores are depleted.

18. Types of Fast (pale) muscle fibers (type II)
Fast oxidative glycolytic fibers (type IIa)
 have both aerobic and anaerobic metabolic
capabilities and are moderately fatigable.
 mid-sized and have more capillaries than fast
fibers.
 high ATPase activity like the fast (anaerobic)
fibers and high oxidative capacity like the slow
(aerobic) fibers.
 contract more rapidly than the slow fibers and
can maintain contraction for a longer period of
time than the fast fibers.

19. Types of Fast (pale) muscle fibers (type II)
Fast glycolytic (type IIx)
 have only a glycolytic capacity and are highly
fatigable.
 In endurance runners, detraining has been shown to
result in a change from fast-twitch IIa to IIx.
 Most muscles of the body are composed of a mixture
of the three types of muscle fibers e.g. gastrocnemius
muscle.
 The muscles which react very rapidly are composed
mainly of the fast fibers while the muscles which
maintain contraction for long periods of time are
composed mainly of the slow fibers.

20. fast-twitch versus slow-twitch muscle
fibers in different types of athletes
Slow-Twitch
Fast-Twitch
82
18
Marathoners
74
26
Swimmers
45
55
Average male
45
55
Weight lifters
37
63
Sprinters
37
63
Jumpers

21. Types of exercises
Aerobic exercise:
 Examples: walking, riding a bike and
swimming.
 Aerobic exercise increases cardio-respiratory
fitness and endurance.
 enables the heart and lungs to supply O2 to
the muscles, so they can sustainecontraction
for a long period.

22. Types of exercises
Aerobic exercise:
 Aerobic or endurance exercises help the
overall fitness.
 improve cardiovascular health, and help in
control of body weight.
 work up to 20 to 30 minutes of aerobic
exercise three times a week.
 You can split up that time into 10-minute
blocks if that's easier on your joints.

23. Types of exercises
Flexibility exercises (Stretching, Range-of-
Motion)
 improve the full range of motion of your
muscles and joints.
 gentle stretching exercises should be done
every day and are the most important of all
your exercises.
 protect your joints by reducing the risk of
joint injury
 warm-up for more strenuous exercise
 relax and release tension from your body.

24. Types of exercises
Flexibility exercises (Stretching, Range-
of-Motion)
 These can be done on land or in water such
as a pool, hot tub or warm bath.
 useful for easing stiff joints in the morning.
 Work up to 15 minutes of flexibility exercises
a day. Once you can do 15 continuous
minutes, you should be able to add
strengthening and aerobic exercises to your
routine.

25. Types of exercises
Resistance (Strengthening) exercise
 such as weight-lifting, increases your muscle
strength by requiring your muscles to lift, push
or pull against something.
 This type of exercise can increase bone density
and help in prevention of osteoporosis.
 These exercises help you build strong muscles
that help support and protect your joints.

26. Types of exercises
Resistance (Strengthening) exercise
 Weight training is an example of a
strengthening exercise that can help you
maintain your current muscle strength or
increase it.
 strengthening exercises is done every other
day, but take an extra day off if your joints
are painful or if you notice any swelling.

27. Different ways which strengthen
the muscles
Isotonic strength training
 during this type the muscles shorten as they
contract.
 This is the most common type of muscle
contraction.
Isometric strength training
 during this type the muscle contracts, but the
muscle length remains the constant.
 This type is popular with bodybuilders and occurs
when you try to move an immovable object.

28. Different ways which strengthen
the muscles
Eccentric
 this type is the opposite of isotonic training.
 Your muscles lengthen as they contract, for
example when you run down hill.
Isokinetic strength training
 this is similar to isotonic training, except that
the muscle contracts at a constant speed.

29. Types of exercise according
to the intensity
Low Intensity (up to 80% HR Max)
 This has the effect of improving general
fitness and improves the muscles' ability to
use O2. This occurs by increasing the number
of capillaries in the muscle.
Medium Intensity (80-85% HR Max)
 This intensity is around anaerobic threshold
(AT) and improves an individual's AT -
allowing the body to work at a higher
intensity while still working aerobically.

30. Types of exercise according
to the intensity
High Intensity (85-90% HR Max)
 This intensity of exercise places a load on the
heart causing it to become stronger so it can
pump more blood in one contraction.
Flat Out (90-100% HR Max)
 In this region the body works completely
anaerobically. This kind of training, improves
the body's anaerobic capacity - the production,
and removal of lactic acid.

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