Movement and Exercise
Vertebrates are animals that have an internal skeleton – those that do not have an internal skeleton are called invertebrates. In humans and other vertebrates, the skeleton has two functions in the GCSE biology curriculum:
- Support – the skeleton enables us to stand as well as enclosing important organs for protection e.g. the brain is enclosed by the skull and the ribs enclose and protect the heart and lungs
- Movement – the skeleton enables complex movement, from standing to sitting and from walking to running
Muscles can only move bones by contracting – so two muscles working in opposition to one another are needed to move an arm up and down, i.e one muscle contracts while the other muscles contracts relaxes – they work in antagonistic pairs.
- To lift the lower arm, the biceps contracts and the triceps relaxes
- To lower the arm, the triceps contracts and the biceps relaxes
A joint is where two bones meet and work together – the bones have to be connected in some way that allows them to move also staying in the same place relative to each other. Joints are adapted to allow smooth movement and to resist the effects of wear and tear.
Usually in GCSE Biology curriculum, we need to know that the different components serve different functions:
- Cartilage – Cartilage (which is smooth) prevents bones from rubbing together and reduces friction.
- Synovial fluid – This helps to lubricate the joint and reduces friction.
- Ligaments – The ligaments (which are elastic) help to stabilise the joints during movement.
- Tendons – They transmit the forces from contracting muscles to the bones near the joint – they are a tough fibrous tissue made from collagen.
Taken together, the specific properties of each part of a joint enable it to function correctly – if there is a problem with one part, the joint will not work correctly.
Exercise programmes can be put together by doctors, nurses, physiotherapists, personal trainers or other experienced specialists – these exercise regimes can be used to train for a sport or to treat a condition such as obesity.
Before starting a new exercise programme it is important to find out:
- Current symptoms – may indicate an existing injury
- Current medication – e.g. use of inhaler – gentle exercise could be better than strenuous exercise
- Alcohol and tobacco consumption – may affect the cardiovascular and respiratory system
- Level of current physical activity – to prevent over-exertion which may cause injury
- Family medical history – e.g. if heart attack is present in the family history – care should be taken before strenuous exercise
- Previous treatments – e.g. surgery after a dislocated shoulder may limit the range of movement
This helps to ensure that the exercise regime is effective and safe e.g. it does not make any health problems worse or does not trigger any other ones.
Body Mass Index (BMI)
A person’s height and mass can be used to determine their body mass index (BMI). In GCSE Biology, by definition, the BMI is a guideline that helps to identify whether a person is a healthy body mass – it is calculated by the following formula:
The BMI does not take into account the proportion of body fat – a person’s body mass (BMI) and the percentage of their body fat can be used to assess their weigh and fitness.
In order to know whether a new training programme has made a positive impact on fitness, in GCSE Biology, it is important to record measurements regularly – these measurements include: blood pressure, resting heart rate, BMI, percentage of body fat, weight lost or gained etc.
Any assessment of progress needs to take into account the accuracy of the monitoring technique and the repeatability of the data obtained.
According to the GCSE Biology curriculum, the human body can withstand a lot of exercise – however excessive exercise (over-exertion or not being properly prepared for exercise) can put the body under a lot of strain, which can lead to injuries including sprains, dislocations and torn ligaments or tendons.
A sprained ankle can occur when the foot turns inward because this puts extreme tension on the ligaments of the outer ankle.
- A sprained knee can be the result of a sudden twist.
- A wrist can be sprained by falling on an outstretched hand.
The symptoms of sprains include the following:
- Swelling – due to fluid building up at the site of the sprain
- Pain – the joint hurts and may throb
- Redness and warmth – caused by the increased blood flow to the injured area
- Being unable to move the joint or put weight on it
When someone suffers a sprain the priority is to reduce swelling and pain and aid rapid recovery and rehabilitation – the treatment follows the principle RICE:
- Rest – avoid moving the joint which could make the injury worse
- Ice – carefully cooling the injured joint can help to prevent swelling
- Compression – a carefully applied support bandage can prevent swelling and support the joint
- Elevation – raising the injured joint lowers blood pressure in that part of the body and prevents swelling
A physiotherapist is a healthcare professional who specialises in treating people who have skeletal-muscular injuries – physiotherapists understand how the body works and can help a patient to re-train or reuse a part of the body that is not functioning properly. This is normally achieved through various exercises to strengthen muscles that may have become weakened.
Pictures from: https://getrevising.co.uk/resources/biology_b7_ocr_21st_century & https://www.impactphysicaltherapy.com/understanding-ankle-sprains/
End of the topic!
Drafted by Gina (Biology)