Since the onset of Covid-19, many patients seeking help from sports physicians have revealed that they are running more frequently or faster or on slopes as they became fitter over time.
In their enthusiasm, some complained of pain on their knees, shins, heels and feet, forcing them to stop temporarily to recuperate.
Training load-related issues, inadequate recovery, running terrain and footwear can precipitate problems. Other factors include poor conditioning, excessive weight, structural issues, soft tissue tightness, muscle imbalances, and running technique.
With virtual events, such as The Straits Times Virtual Run's 175km race, covering long distances, it is imperative for participants to know how to identify - and deal with - common running injuries.
Pain on the front of the knee is usually due to patellofemoral (kneecap) pain or patella tendinopathy.
Runners typically report pain that worsens after prolonged running or when squatting, jumping or climbing stairs.
In older individuals, when there is also swelling of the knee, there may be underlying osteoarthritis.
The iliotibial band is a thick band running down the outer aspect of the thigh that may rub over the outside of the knee and cause iliotibial band friction syndrome.
Hamstring injuries may also occur, especially with sprinting, manifested by a "pop" or tearing sound behind the knee accompanied by swelling and sometimes bruising.
Pain over the front of the shin could have its origin in the muscle, tendon, periosteum (sheath covering bone) or bone itself.
Medial tibial stress syndrome typically manifests as pain over a long segment of the inner shin during a run and may persist for hours to days when the condition worsens. It is important to distinguish this from a stress fracture (crack in the bone) of the tibia where pain is more localised.
Chronic compartment syndrome is where a runner reports increasing pain with "hardening" of the muscle that resolves upon slowing down to rest.
The Achilles tendon can acutely swell up, becoming red, hot and painful, or manifest as a chronic swelling with mild pain that goes away when you are warmed up. Where the tendon inserts onto the heel bone, occasionally a painful bump might appear.
Plantar fasciitis is another common heel condition that hurts on your first step on the floor in the morning after getting up from bed, and diminishes after a few steps or a few minutes.
Ankle and foot pain
Through repetitive pounding and pushing off, you could develop metatarsalgia which is pain over the forefoot across the second through the fourth metatarsal heads.
There are many causes, including toe deformities, abnormal gait, trauma, bursitis and interdigital neuroma.
Stress fractures can occur, commonly at the second and third metatarsal bones.
Tendinopathy of the foot and ankle is common, especially when there is previous foot or ankle injury, presenting with pain after prolonged activity.
Common tendons involved include tibialis posterior (inner ankle), peroneal (outer ankle) or tibialis anterior (front of ankle).
What can we do to help ourselves?
A large majority of injuries are related to overuse or inadequate recovery from training.
Beginner runners should start with a relatively shorter distance, intensity and frequency, especially if they have been sedentary for a prolonged period.
A good starting point is to maintain a moderate pace (can talk but not sing; 60-70 per cent maximum heart rate) for 30 minutes once or twice a week, mixing in brisk walking to keep overall fatigue low.
Gradually increase this over weeks to months, aiming for 150 minutes a week.
Footwear is important too. Choose a shoe that is comfortable, fits well and suits your foot shape and demands. Replace your shoe if it starts to wear out.
A good quality running shoe is designed to last between 600km and 800km, though it depends on factors like running terrain and body weight.
Exercise on elliptical machines or swim, walk and cycle for cross-training to maintain fitness while working through running-related pains. Incorporate a regular stretching routine.
In addition, strength training has been shown to reduce the risk of overuse injuries by up to half, and should ideally be included two to three times a week.
Overall recovery is also important, so aim to eat a healthy balanced diet, get adequate sleep and manage external stressors.
When should we seek medical attention?
Mild discomfort may be experienced initially when starting to run regularly. This is normal and should not gradually worsen.
However, persistent pain or swelling in spite of rest should not be ignored and signals the need to seek medical advice.
You may need imaging studies such as an X-ray, ultrasound scan or MRI to determine the exact nature of the problem.
Your doctor may prescribe medication, refer you to a physiotherapist or a podiatrist to have your gait analysed or be fitted with a foot orthosis.
Injections, extracorporeal shockwave therapy or surgery may be recommended where indicated.
Dr Teoh Chin Sim is a senior consultant and Dr Benjamin Soh is a registrar. Both are from the sports and exercise medicine department at Khoo Teck Puat Hospital.