Anaerobic Exercise and Muscular Strength
Anaerobic exercisescause muscles to get bigger and stronger. Anaerobic exercises use a
resistance against which the muscle has to work to lift or push away. The resistance can be
a weight or a person’s own body weight, as shown inFigure16.27. As a result of repeated
muscle contractions, muscle fibers build up larger energy stores and the muscle tissue gets
bigger. The larger a muscle is the greater the force it can apply to lift a weight or move a
body joint. The muscles of weight lifters are large, and are therefore strong.
Figure 16.27: Anaerobic exercises involve the muscles working against resistance. In this
case the resistance is the person’s own body weight. ( 11 )
Aerobic Exercise and Muscular Endurance
Aerobic exercisesare exercises that cause your heart to beat faster and allow your muscles
to use oxygen to contract. Aerobic exercise causes many different changes in skeletal muscle.
Muscle energy stores are increased, the ability to use oxygen improves, and more capillaries
surround the muscle fibers. These changes result in the ability of the muscle to avoid getting
tired, and to use oxygen and food more efficiently. Aerobic exercise also helps improve
cardiac muscle. It results in the heart being able to pump a larger volume of blood with
each beat due to an increase in the size of the heart’s ventricles. Examples of an aerobic
exercise are shown inFigure16.28.
Both aerobic and anaerobic exercises also improve the ability of the heart to pump blood
around the body. Aerobic exercise causes the heart to get bigger, and anaerobic exercise
causes the walls of the heart to get thicker. These changes allow the heart to push more
blood throughout the body with every heartbeat.
Keeping Muscles Healthy
Being physically active for 60 minutes a day for at least five days a week improves your
physical fitness. Being physically active can also help you to reduce your risk of developing