• Dehydration and salt depletion in our body (after profuse sweating) causing muscles contract involuntarily;
• Accumulation of lactic acid in muscles

Symptoms:Muscles are sore, contract and twitch involuntarily

• Start stretching regime several months before the event for improving flexibility. (Refer to stretching exercise)
• Have proper rest and sleep the night before, regular stretching and warm-up exercises in the whole trail are encouraged
• Develop muscular strength and muscular endurance (Refer to muscular training exercises)
• Have electrolyte-containing drink regularly to replenish lost body fluid and salts

• Have frequent short break when possible; massage and stretch the tight muscles.
• Have electrolyte-containing drinks regularly to replenish lost body fluid and salts.
• Stop participating in the event when essential.

Causes: Sudden or persistent stretch of the muscle that excess its normal limits

Symptoms: (i) Muscles are sore, contract and twitch involuntarily、(ii) Swollen muscles due to the damage of blood capillaries and lymphatic vessels

Precaution Measures: (i) Start stretching regime several months before the event for improving flexibility (Refer to stretching exercise), (ii) Have proper rest and sleep the night before, regular stretching and warm-up exercises in the whole trail are encouraged, (iii) Develop muscular strength of legs and muscular endurance (Refer to muscular training exercises), (iv) Avoid difficult, power demanding activities at extreme / overstressed range of motion

Causes: Persistent frictions between the foot and the socks / shoes lead to the leakage of lymph fluid between the skin and the muscle.

Symptoms:Blisters are produced at pressure point, painful and cannot bear weight.

Precaution Measures: (i) Choose the running shoes that best fit your feet and wear blend fabrics quick-dry socks, (ii) If there is a particular place reddened on the feet, blisters may occur at that particular site sooner or later. Pads or lotion can be applied for reducing friction and pressure in advance, (iii) Taping feet with adhesive bandage, (iv) Double socking and change socks frequently during event, (v) Develop sufficient muscular strength and endurance to reduce unnecessary feet motion. (Refer to muscular training exercises)

Acute Management:(i) Do not try to puncture the blisters if possible, use pad to spare the blisters from pressure, (ii) If the blister has to be punctured, qualified medical officers with appropriate disinfection procedures are required to prevent infection.

• Over sweating will lead to dehydration, loss of electrolyte and so reduction of blood volume. Hence many biochemical reactions cannot function properly; muscles also do not have sufficient oxygen or nutrients supply.
• Dehydration & electrolyte imbalance can increase the chance of getting heat stroke.

Symptoms: Dizziness, overtiredness, muscle cramp, unconsciousness

Precaution Measures: Have 100-250mL of liquid with electrolytes and salt-containing drinks or foods every 20-30 minutes

Acute Management: (i) Stop all ongoing exercises, have an electrolyte-containing drink to replenish the lost body fluid and salts, (ii) If the patient is unconscious, do not give water to the patient. Should call for emergency care immediately.

Causes: If a meal or adequate calories was not taken before the event, coupled with the large quantity of energy consumption during exercises, low blood sugar level may result.

Symptoms: Pale appearance, wet and cold skin, shallow breathing, overtiredness or dizziness. Convulsion may happen in severe cases.

• Well decide a proper diet for the event / training
• Water intake only is sufficient for exercise less than 90 minutes.
• Sport drinks with sugars and electrolytes as well as food with carbohydrates are preferred for exercise over 90 minutes.

Acute Management: (i) Stop all on-going exercise, consume sugar drink, (ii) In the most serious situation, if one has extremely low blood sugar level and is unconscious, call for emergency care immediately.

Heat Exhaustion Causes: Over sweating leading to dehydration and electrolyte imbalance.

Heat Exhaustion Symptoms: Normal body temperature or rises to about 1oC, excessive sweating, fast and weak pulse, blood pressure decreased, unconscious and fainting may be experienced in extreme cases.

Heat Stroke Causes: Body temperature rise rapidly to cause dysfunction of heat control center in the central nervous system.

Heat Stroke Symptoms: Body temperature above 40oC, hot and dry skin, fainting, anxious, accelerated breathing and pulse rate, unconsciousness and convulsion happen in most serious situations.

Precaution Measures: (i) Frequent replenish cool drinks (~15-20°C) during exercise, (ii) Wear comfortable and breathable clothing. Its materials should be in good ventilation with heat-dispersion technology and cutting, (iii) Bring along umbrellas or caps to prevent direct absorption of sunlight energy, (iv) Slow down or stop exercise once there are symptoms. Never overexert.

Acute Management: (i) Stop all on-going exercise and take a rest in the shade, (ii) Remove excessive clothing, spray water on the body or use a wet towel to help reduce body temperature, (iii) Consume cold water or electrolyte-containing drinks, (iv) If one loses consciousness, call for emergency care immediately.

Causes: Rapid drop in temperature and lack of sufficient clothing in a cold place or sudden rain can cause hypothermia.

Symptoms: Clammy skin, shivering, exhaustion, stumbling, muscle spasms, stammering and hallucinations.

Safety Guidelines: (i) Have a good sleep the night before the event and rest properly during the event. Don't overload or overstrain yourself

Emergency Measures: (i) Change the wet clothes immediately, (ii) Cover head, neck and body with dry clothes or cold packs to keep warm, (iii) Consume hot drinks and high calorie food to raise and maintain body temperature

• Plantar fascia connected to the sole region is subjected to repeated stress, resulting in micro-tear.
• Predisposing factors are rapid increase in training mileage, frequency or slope training in a short period of time. Insufficient muscular strength and flexibility of ankle, poor lower limb alignment (e.g. flat feet) and poor running shoes design are also related.

• Severe pain on feet, especially the first step every morning
• Immature pain would be diminished by warm-up and exercise, but it would deteriorate that pain may be experienced even in usual life.

• Using tailor-made insoles can improve condition and reduce recurrence.
• Gradually reduce the training intensity and volume. Avoid training on slopes. If pain persists, stop running and substitute it by running in chest-deep pool, swimming or cycling.
• Ice can suppress inflammation and reduce pain. If the situation persists, one should receive physiotherapy, including manipulative therapy, electrophysical therapy and sport tapping etc to improve condition.
• Stretching exercise of hamstrings, calf muscle and plantar fascia (Refer to stretching exercise)

Example - Stretching exercise of Right Plantar Fascia (Sole of right foot)

1. Raise up right toes by pressing again the wall / steps
2. Ensure the ball of big toe still touch the floor

Strengthen the calf muscle and the Tibialis Posterior muscle (Refer to muscular training exercises)

Example - Tibialis Posterior strengthening exercise

1. Raise and keep the medial foot arch
2. Ensure the ball of big toe still touch the floor

• If the pain is relieved, training can be resumed. But ensure the distance and the intensity is reduced. The training surface should not be too hard.
• Gradually increase training intensity/distance by 10% every week. If pain recurs, then keep that intensity or even reduce it again.

Causes: Recent researches found that the over tight soft tissue at the lateral side of the knee, medial knee muscle weakness or muscle imbalance, abnormal lower limb alignment (e.g. Genu valgus and flat feet) pull the knee cap into an abnormal track that triggers pain or even chronic inflammation.

• Pain triggers under kneecap when walking down hill / stairs, bending the knees fully, squat or after prolonged sitting
• Crepitation or giving way may be experienced

• Stretching exercise of quadriceps, hip flexor and iliotibial band (Refer to stretching exercise)
• Strengthen the quadriceps, medial knee and Gluteal muscles (Refer to muscular training exercises)

Example - Right Gluteus Medius Strengthening Exercise

1. Lie on your side and bend your knees as 90°
2. Spread the right hip slowly out (Separate your legs)

1. Ice can suppress inflammation and reduce pain. If pain persists, stop running and substitute it by jogging on grassland, running in chest-deep pool, swimming or cycling.
2. Avoid exercise with much stress on kneecap, e.g. jumping, running downhill and stairs walking etc.
3. Using tailor-made insoles can improve condition and reduce recurrence.
4. If the situation persists, one should receive physiotherapy, including exercise therapy, manipulative therapy, electrophysical therapy and sport tapping etc to relign the kneecap and correct the pathobiomechanics.

If the pain is relieved, training can be resumed. But ensure the distance and the intensity is reduced. Apply ice before and after exercise. Training with knee sport tapping. Most importantly, muscle strengthening and recruitment training needs to be maintained.