Revision notes for Edexcel A A Level Biology Exercise risks, medical technology and performance ethics. Open the guide for explanations and worked examples. Written against the Edexcel A A Level Biology (9BN0) specification, so the content matches what's examinable rather than general Biology background.
Exercise risks, medical technology and performance ethics
What you'll learn
- How to distinguish normal training stress from harmful exercise-related risk.
- How to use simple quantitative data to compare injury risk.
- How medical technologies such as ECGs, MRI scans and keyhole surgery are used in sport and exercise.
- How to evaluate performance enhancement using both biology and ethics.
Exercise: beneficial, but not risk-free
Exercise usually improves health. It can increase cardiovascular fitness, strengthen bones and muscles, improve insulin sensitivity, and reduce the risk of diseases such as cardiovascular disease and type 2 diabetes.
However, exercise also exposes the body to mechanical stress and physiological stress. Mechanical stress means forces acting on tissues such as bones, muscles, tendons and ligaments. Physiological stress means extra demand on body systems, such as increased ventilation, heart rate and body temperature.
Definition
Risk and incidence
Risk is the probability that harm will occur. Incidence is the number of new cases of an event, such as injury, in a defined population over a defined exposure period.
A key point is that “exercise risk” should not be judged just by counting injuries. You need to know how much exercise people actually did. Ten injuries in 100 hours of sport is a much higher rate than ten injuries in 10 000 hours.
Types of exercise-related risk
Acute injury
An acute injury happens suddenly. Examples include:
- a sprain, where a ligament is stretched or torn
- a strain, where muscle fibres or a tendon are damaged
- a fracture, where a bone breaks
- a dislocation, where bones at a joint are forced out of position
- concussion, which is a brain injury caused by impact or rapid acceleration of the head
Chronic or overuse injury
A chronic injury develops gradually. An overuse injury happens when repeated stress causes damage faster than repair can occur. Examples include tendinitis, stress fractures and shin splints.
Physiological risks
Exercise can also cause problems such as dehydration, heat exhaustion, hypoglycaemia in susceptible people, or rarely sudden cardiac events in people with underlying heart conditions.
Key Idea
Risk depends on exposure
To compare risks fairly, always consider the amount of exposure: the number of participants, the duration of activity, and the intensity or type of exercise.
A common way to compare injury risk is:
injury incidence=number of new injuriestotal exercise exposure time×1000\text{injury incidence}=\frac{\text{number of new injuries}}{\text{total exercise exposure time}}\times 1000injury incidence=total exercise exposure timenumber of new injuries×1000This gives injuries per 1000 hours of exercise.
Example
Comparing injury incidence
A running club records 18 injuries during 1200 hours of training. A swimming club records 10 injuries during 1600 hours of training.
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Calculate the running injury incidence:
181200 h×1000=15 injuries per 1000 h\frac{18}{1200\ \text{h}}\times 1000=15\ \text{injuries per 1000 h}1200 h18×1000=15 injuries per 1000 h -
Calculate the swimming injury incidence:
101600 h×1000=6.25 injuries per 1000 h\frac{10}{1600\ \text{h}}\times 1000=6.25\ \text{injuries per 1000 h}1600 h10×1000=6.25 injuries per 1000 h -
Compare the two rates:
156.25=2.4\frac{15}{6.25}=2.46.2515=2.4The recorded injury incidence is 2.4 times higher in the running club, but you should still consider factors such as training intensity, age, previous injuries and reporting accuracy.
Common Mistake
Counting injuries without exposure
Do not conclude that one sport is “more dangerous” just because it has more injuries in total. A sport with more participants or more training hours may naturally have more recorded injuries.
Managing risk during training
Training causes adaptation only if the body has time to recover. Adaptation is a long-term beneficial change in response to a stimulus, such as increased stroke volume or stronger connective tissue.
Important risk-reduction principles include:
- progressive overload: increasing intensity, duration or frequency gradually
- appropriate warm-up and cool-down
- suitable footwear and equipment
- correct technique
- adequate recovery and sleep
- hydration and temperature control
- stopping exercise if symptoms suggest injury or illness
Overtraining is a decline in performance caused by excessive training and inadequate recovery. It may involve persistent fatigue, poor sleep, frequent infections, low mood and increased injury risk.
Medical technology in exercise and sport
Medical technology means tools, procedures or devices that apply scientific knowledge to diagnose, monitor, treat or manage health problems. In exercise and sport, technology can help detect injury, guide treatment, monitor recovery and sometimes allow people with impairments to take part in physical activity.
ECGs and heart monitoring
An electrocardiogram, or ECG, records the electrical activity of the heart using electrodes placed on the skin. A normal ECG trace includes:
- the P wave, caused by atrial depolarisation
- the QRS complex, caused by ventricular depolarisation
- the T wave, caused by ventricular repolarisation
An arrhythmia is an abnormal heart rhythm. ECGs can help detect arrhythmias that may increase risk during intense exercise.
Example
Estimating heart rate from an ECG
An ECG trace shows that the time between two R waves is 0.80 s.
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Use the R-R interval because each R wave corresponds to one ventricular contraction, so one R-R interval represents one heartbeat.
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Substitute into the heart rate calculation:
heart rate=60 s min−10.80 s=75 beats min−1\text{heart rate}=\frac{60\ \text{s min}^{-1}}{0.80\ \text{s}}=75\ \text{beats min}^{-1}heart rate=0.80 s60 s min−1=75 beats min−1 -
Interpret the value. A heart rate of 75 beats min⁻¹ is within the typical resting adult range, but rhythm regularity and the person’s symptoms also matter.
Imaging technologies
An X-ray image uses ionising radiation to show dense structures such as bone. It is useful for detecting fractures.
A CT scan, or computed tomography scan, uses many X-ray images processed by a computer to create cross-sectional images. It gives more detail than a simple X-ray but involves a higher radiation dose.
An MRI scan, or magnetic resonance imaging scan, uses strong magnetic fields and radio waves to produce detailed images of soft tissues such as muscles, ligaments, tendons and cartilage. It does not use ionising radiation.
Common Mistake
Radiation risk
X-rays and CT scans use ionising radiation, which can damage DNA. The medical benefit must outweigh the risk, especially if repeated scans are being considered.
Treatment and assistive technologies
Arthroscopy is keyhole surgery on a joint, using a small camera and instruments inserted through small incisions. It can be used to diagnose or repair cartilage or ligament damage.
A prosthesis is an artificial replacement for a missing body part, such as a prosthetic limb. An orthosis is a device that supports or corrects an existing body part, such as a brace.
These technologies can be life-changing, but they also raise questions:
- How safe is the technology in the short and long term?
- Is the athlete being pressured to return too soon?
- Is access fair, or limited by cost?
- Does the technology restore typical function, or enhance performance beyond typical function?
Common Mistake
Assuming treatment means no risk
Successful surgery or rehabilitation does not mean a tissue is identical to an uninjured tissue. Scar tissue, altered movement patterns and reduced strength can all affect future injury risk.
Performance enhancement and doping
Performance enhancement means using a method or substance to improve physical or mental performance. This can include legal methods, such as training, nutrition and altitude acclimatisation, as well as banned methods.
Doping means using prohibited substances or methods to improve performance. A substance may be banned because it gives an unfair advantage, risks harm, violates the rules of the sport, or conflicts with the spirit of sport.
Common examples include:
- Anabolic steroids: synthetic substances similar to testosterone. They can increase protein synthesis and muscle mass, but may cause liver damage, high blood pressure, infertility, acne, mood changes and masculinisation.
- Erythropoietin, or EPO: a hormone that stimulates red blood cell production. Extra red blood cells increase oxygen-carrying capacity, but also increase blood viscosity, raising the risk of thrombosis, stroke and heart strain.
- Blood doping: increasing red blood cell concentration by transfusion. It has similar endurance benefits and risks to EPO misuse.
- Stimulants: substances that increase alertness and reduce perceived fatigue. They can increase the risk of arrhythmia, overheating and addiction.
Tip
Legal does not always mean risk-free
Some substances are permitted in sport but can still have side effects, especially at high doses or when combined with intense exercise.
Treatment versus enhancement
A treatment aims to restore normal function or health. An enhancement aims to increase performance beyond the usual healthy range.
The boundary can be difficult. For example:
- an inhaler for a diagnosed asthmatic athlete may be treatment
- the same drug used without medical need may be enhancement
- a prosthetic limb may restore mobility
- an advanced prosthesis may raise questions about classification and competitive advantage
Key Idea
Science and ethics are linked but different
Biology can explain what a technology does to the body. Ethics asks whether using it is acceptable, fair and safe in a particular context.
Example
Weighing EPO use in endurance sport
An endurance athlete wants to use EPO to improve performance.
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Apply the biological mechanism. EPO increases red blood cell production, so haemoglobin concentration may rise and more oxygen can be transported to respiring muscles.
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Weigh the health risk. A higher red blood cell concentration increases blood viscosity, so the heart works harder and the risk of blood clots, stroke and cardiac events increases.
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Apply ethical principles. EPO misuse creates an unfair advantage, may pressure other athletes to take health risks, and breaks anti-doping rules. Unless it is medically prescribed under a legitimate therapeutic exemption, it should not be allowed in competition.
Evaluating evidence and claims
When you read a claim about exercise risk, recovery technology or performance enhancement, ask:
- Was there a control group?
- Was the sample size large enough?
- Were participants matched for age, sex, training status and previous injury?
- Was the outcome measured objectively?
- Is the study showing causation, or only correlation?
- Are there conflicts of interest, such as commercial funding?
Common Mistake
Correlation is not causation
If athletes using a supplement perform better, that does not prove the supplement caused the improvement. They may also train more, have better coaching, or differ genetically.
Exam technique
In the exam
- Separate the biological effect from the ethical judgement: explain what happens in the body first, then evaluate fairness, safety and access.
- Use quantitative risk data carefully: compare rates, not just totals, and mention exposure time where relevant.
- For medical technologies, link the tool to the tissue or problem: ECG for heart electrical activity, X-ray or CT for bone, MRI for soft tissue, and arthroscopy for joint diagnosis or repair.
Self review
Check yourself
- Why is injury incidence per 1000 hours more useful than total injury number?
- How does EPO improve endurance performance, and why is it risky?
- What factors would you consider when deciding whether a sports technology is treatment or enhancement?
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