The effects of percussive massage therapy on thoracolumbar fascia structure in low back pain patient
Description
Fascia plays a potential role in developing chronic diseases[1], even cancer[2]. As the largest fascial structure in the body, the thoracolumbar fascia (TLF) is a composite structural material consisting of tendons and fascial planes that connects the latissimus dorsi and gluteus maximus muscles[3]. Its primary function is to help stabilize the spine and transmit forces between the lumbar spine and pelvis[4]. At the beginning of the twenty-first century, Langevin M proposed an interactive model of the pathogenesis of thoracolumbar fascia and lower back pain[5]. A subsequent series of studies found that the thoracolumbar fascia in patients with low back pain showed thickening[6], reduced shear strain[7], and structural disturbances [8] compared to individuals without low back pain. These changes in the TLF may induce pain by stimulating A- and C-fiber nociceptors[9, 10]. Fascial thickening has been found to vary, even in healthy individuals[11]. This is associated with fascial densification caused by overuse[12]. The abnormality of the fascial structure could be reversed by applying mechanical forces (twisting, tension, compression, stretching, bending and friction, percussion) to the soft tissues [5, 13, 14]. This phenomenon may be attributed to mechanical stimulation that increases the local strain on the loose connective tissue, causing hyaluronic acid hydration to reduce the viscosity[15]. Treatment of deep fascia requires adequate, and sustained pressure[16], thereby therapists often use power tools, such as handheld percussion devices, to improve fascial function[17, 18]. Recently, handheld percussive massage therapy (PT) has received increasing attention. Different manufacturers (e.g., Theragun, Hyperice) offer this equipment for self-massage or therapist treatment, which can usually provide up to 53Hz percussion frequency, 16mm amplitude, and various massage heads that can be matched to different body parts. Due to its portability and stability, PT is favored by the physical therapist community and sports people[17]. Available evidence suggests that PT can increase range of motion(ROM), improve recovery, and reduce muscle pain and stiffness [19–22]. The mechanism may be related to continuous percussion stretching the muscle fiber, causing collagen remodeling and elastin changes[13, 23], affecting the fascia's densification, adhesions, and viscoelastic properties [12]. A review showed that most therapists use PT to treat myofascial syndrome [17]. Although percussion massage has been widely used in therapeutic practice, there are no relevant studies on whether PT can affect the fascial structure. This study aims to investigate the effects of PT on TLF morphology and other related outcomes. We hypothesized that 15 min of PT would reduce participants' TLF thickness, echo intensity of the ROI (range of interest) on TLF, and perceived stiffness, as well as increase skin temperature and lumbar flexibility.