Muscles – the structure and function of the muscular system
Section 2: Muscles – the
structure and function of the
There are over 700 skeletal muscles in the human body. Skeletal muscles cross over joints via a tendon and create
the movement of the body. They help to maintain correct posture and keep the joints stable and in the correct
position and alignment. They work voluntarily and are under our ‘conscious’ control. The main ones are:
We also have two other types of muscle:
Smooth muscle tissue is found in the internal systems of the body, including the digestive, circulatory, urinary and
reproductive systems. Smooth muscle works involuntarily; it is not under our ‘conscious’ control.
Principles of anatomy and physiology for fitness and physical activity
Cardiac muscle is only found in the heart. It
works continuously to pump blood and oxygen
around the body. It works involuntarily, that is,
it is not under our conscious control.
Muscles account for much of our body weight:
around 40% of male body weight and slightly
less for females, because women have a
higher proportion of essential fat mass
(needed to maintain the menstrual cycle and
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Healthy eating and hydration
Check the label on
Each serving (150g) contains
Fat Saturates Sugars Salt
3.0g 1.3g 34g 0.9g
LOW LOW HIGH MED
of an adult’s reference intake
Typical values (as sold) per 100g: 697kJ/ 167kcal
Choose foods lower
in fat, salt and sugars
Use the Eatwell Guide to help you get a balance of healthier and more sustainable food. It
shows how much of what you eat overall should come from each food group.
Fruit and vegetables
Eat at least 5 portions of a variety of fruit and vegetables every day
Choose wholegrain or higher fibre versions with less added fat, salt and sugar
Potatoes, bread, rice, pasta and other starchy carbohydrates
Water, lower fat
tea and coffee all
Limit fruit juice
to a total of
150ml a day.
s Low fat
Eat less often and
in small amounts
Beans, pulses, fish, eggs, meat and other proteins
Eat more beans and pulses, 2 portions of sustainably
sourced fish per week, one of which is oily. Eat less
red and processed meat
Dairy and alternatives
Choose lower fat and
lower sugar options
Per day 2000kcal
Oil & spreads
Choose unsaturated oils
and use in small amounts
2500kcal = ALL FOOD + ALL DRINKS
Source: Public Health England in association with the Welsh Government, Food Standards Scotland and the Food Standards Agency in Northern Ireland © Crown copyright 2016
Every system depends on other
systems for optimal functioning.
The body is a living structure comprised of many
finely integrated and interconnected systems.
Each system can be described independently and
separately, but it is important to remember that they
are actually interdependent.
GROWTH AND REPAIR
ENERGY AND INSULATION
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The principles of training
2-3 days a week, with
rest days between
working the same
muscles, 1 set of 8-12
Muscular strength is: ‘the ability of the muscles to contract forcefully and maximally
to lift heavy weights’. Maximal strength is the amount of weight that can be lifted for
one repetition, e.g. an olympic power lift.
Muscular endurance is: ‘the ability of the muscles to contract repeatedly over a
given period of time without fatigue’. It is being able to lift a lower weight for more
Examples of activities requiring muscular strength and endurance include: all
sporting events such as: power lifting and heavy weight training (strength) or running,
cycling, circuit training (endurance); daily activities, lifting and moving heavy objects
(strength), carrying bags (endurance).
At least 3 days a week,
all muscles. We can
stretch every day. Only
stretch muscles when
they are warm.
Examples of activities requiring muscular strength and endurance
Flexibility is: ‘the ability to move the joints through their full range of movement’.
Examples of activities requiring flexibility include: gymnastics, trampolining, dance,
yoga and daily activities where we need to reach and bend.
Principles of active, healthy living
Examples of activities requiring flexibility
Motor skills include: balance, co-ordination, speed, power, reaction time. All activities will require a combination of
motor skills. Some activities use some skills more than others.
For example: walking a tightrope will require lots of balance; a choreographed dance routine will require lots of coordination;
a sprint start from the blocks will require good reaction time; a javelin throw will require power.
Examples of activities requiring use of motor skills
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The main components of a fitness and activity session
Assessing health and fitness
Simple assessments can be conducted at the start or at certain points throughout a fitness programme. These
assessments can be used to check any changes that may occur.
There are many different assessments that can be used. These include:
• Height and weight
• Body mass index
• Waist-to-hip ratio
• Muscular strength
• Muscular endurance
Height and weight
Height and weight tables provide guidelines for a healthy body weight. They are also a valid method of gauging body
mass index (BMI).
To ensure that accurate measurements are gathered the following steps must be adhered to.
Body mass index (BMI)
• Resting heart rate
• Blood pressure
• Use calibrated scales, make sure the participant removes
shoes and heavy clothing and ensure all retests are
scheduled for the same time of day.
• Make sure the participant removes shoes and stands tall.
Take the highest part of the head as the measurement (be
aware that height decreases as the day goes on).
• Motor skills
Assist in the delivery of a fitness or physical activity session
BMI is the standard measure used for clinical diagnosis of obesity.
It predicts health risks for most people accurately. It is not a reliable
indicator for strength athletes and bodybuilders (around 2% of the
population) because it only takes height and weight into account –
not body composition. Bodybuilders with very low levels of fat are
often classified as ‘obese’ by this method.
BMI is a quick and easy gauging method. A BMI reading of 30 or
more is classified as obese.
BMI (kg/m 2 )
Start Finish Teaching points
• Keep close to the step/bench
• Make sure the whole of the foot is in contact with
• Stand up tall at the top of the movement
• Keep abdominals engaged
• Knees are soft
• Gluteus maximus
RESISTANCE BAND- LOW ROW
• Use a small step
• Hold a weight
• Sit up straight with the abdominals engaged
• Keep the knees slightly bent
• Ensure that the resistance band is safely around the
middle of the feet
• Palms of the hands facing in
• Keep the elbows soft and tucked into the waist
Assist in the delivery of a fitness or physical activity session
• Latissimus Dorsi
• Perform the exercise whilst standing. Wrap the band
around something secure
• Perform a single arm row
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