Muscle biopsy
ProcedureLocal anesthesia was applied to the superficial skin covering the MTrP of each participant. Percutaneous biopsy sampling optimized with a suction-enhancement technique was used to obtain muscle biopsies of the m. trapezius MTrP or the m. gluteus medius MTrP from each participant using small Bergstrom muscle biopsy needle, 8 swg (4.0mm) x 100 mm (Dixons Surgical Instruments, Essex, United Kingdom).