I felt an electric shock in my left front thigh while doing knee lifts with my right leg. I was standing up shadow boxing and when I bent backwards and threw out my right knee my left leg had an incredible electric shock and I felt a tear in the front muscle in my left thigh.
Hello, The electric shock feeling can be due to nerve and not due to muscle. I think you have a nerve entrapment in the lumbar spine and that's the cause for electrical shock feelings.  As any Injury to the nerve may lead to abnormal sensations.  When it's related to muscle there will be a dull ache and not the sharp shooting pain.  Take the McKenzie maneuver position while the shocks come and see if reduced.  If so than it is nerve pathology. McKenzie maneuver you can find online easily. Do core stability, spinal muscle strengthening exercises this should help reduce the symptoms. Hope I have answered your query. Let me know if I can assist you further. Take care Jay In Chat Doctor. 