Tender trigger points typically develop from lack of stretching or improper stretching and can also be caused from stress/trauma, overexertion, poor conditioning, or overuse of a muscle. Trigger point pain in the knee and upper thigh is commonly caused by:

• a twisted knee affecting the upper leg muscles
• demanding sports that put excess stress on the upper leg and muscles around the knee (i.e. dance, climbing, gymnastics, martial arts)
• starting up a seasonal activity (i.e.skiing, gardening) too quickly without keeping the muscles active throughout the year
• tight hamstrings causing overstress on the quads and knee
• one leg shorter than the other
• sitting for long periods of time
• repetitive forceful hip flexion (i.e. soccer kicks, jogging, hurdling)
• a direct hit to the quadriceps
• repeated bending and straightening (i.e. squats, deep knee bends, jumping)
• training on a steep slope

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