A "muscle trigger" refers to a specific spot on your body that, when touched or stimulated, can cause a muscle to tighten up or feel sore. It is often associated with muscle knots or spasms and can cause discomfort or pain. Full definition
For the last two months I worked with a trainer to strengthen the hamstrings and starting to work with PT with ultrasound and muscle stimulation modalities as well as muscle trigger point massage. (sock-doc.com)
Many acupuncture points correspond to nerve bundles or muscle trigger points. (mindbodygreen.com)
Often muscle trigger points (sore spots) can be found in the calf muscles, especially just behind the tibia — that's your main shin bone as people know it. (sock-doc.com)