The Effects of Gluteus Medius Trigger Points on Hip Passive Range of Movement and Muscle Strength in People With Chronic Non-specific Low-Back Pain
Active trigger points (TrPs) are proposed to cause restricted range of movement (ROM) and muscle weakness. Simons and Travell pioneered TrP research with their publications of “The Trigger Point Manuals” (1983 & 1992); subsequently research into TrPs has informed knowledge of musculoskeletal disorders. The prevalence of TrPs in people with chronic non-specific low back pain (CNSLBP) is high; especially in the gluteus medius (GMed) muscles. CNSLBP is a complex and costly condition; for which treatment is not always successful. In this population, decreased hip range of movement (ROM) and hip muscle weakness are common findings. This study investigated if the presence of active GMed TrPs was associated with these deficits in the hips, when compared with participants with latent TrPs, and zero TrPs. Forty-two participants with CNSLBP underwent hip passive ROM and hip muscle strength testing; followed by palpation of their GMed muscles to identify the presence and types of TrPs. Analysis showed varying results regarding hip ROM and TrP status. There was an association between hip strength and TrP status. Participants with zero TrPs were the strongest and those with TrPs were weaker. In general, those with latent TrPs were the weakest. This study adds knowledge to the role that TrPs play in muscle strength and the characteristics of TrPs. This is significant for the treatment of CNSLBP and the development of more effective treatments of this multi-factorial condition.