What causes weak and unstable knees after running?

The knee refers to the knee joint. Feeling weakness or instability in the knee joint after running may result from physiological causes, or could be due to pathological conditions such as ligament injury or meniscus damage. Timely medical attention is recommended. Specific analyses are as follows:

I. Physiological Causes

Engaging in prolonged physical activities such as running or basketball increases stress on the knee joint, leading to excessive lactic acid production in muscles, which can impair blood circulation and cause sensations of soreness and weakness. This condition typically does not require special treatment. Adequate rest is recommended, and massage or heat application may be considered when necessary.

II. Pathological Causes

1. Ligament Injury

When the knee joint experiences external force or prolonged loading, ligaments may become overstressed, resulting in injuries of varying severity. Symptoms include leg weakness, knee pain, and swelling. After diagnosis, medications such as pregabalin capsules, glucosamine hydrochloride capsules, or tramadol hydrochloride sustained-release tablets may be prescribed to relieve pain.

2. Meniscus Injury

In individuals who lack regular physical exercise, suddenly engaging in outdoor activities can excessively strain the meniscus, potentially causing damage to surrounding ligaments and leading to muscle atrophy and general fatigue. If the condition worsens, treatments such as partial meniscectomy or meniscus repair surgery may be performed under medical guidance. Post-surgery, overexertion and fatigue should be avoided.

Besides the above-mentioned causes, conditions such as osteoarthritis, synovitis, or gout may also be responsible. Patients experiencing these symptoms should seek prompt medical care, ensure sufficient rest, and reduce unnecessary outdoor physical activity.