Low back pain (LBP) is a significant global health problem. It occurs in all age groups from children to the elderly. Costs associated with health care and work disability attributed to LBP vary between countries and are influenced by social and health care approaches.~In almost all people with LBP, it is not possible to identify a specific cause. Only a small proportion of people have a well-understood pathological reason e.g., a vertebral fracture, malignancy, or infection. On the other hand, non-specific chronic low back pain (NSCLBP) accounts for about 85% of LBP patients treated in primary care, and the vast majority of patients with LBP seen by physical therapists are classified under this designation.~A recently published systematic review examined the impairment of lower extremity muscle strength in LBP disorders. The researchers reported a significant reduction in hip abductor, extensor, and knee extensor strength in patients with LBP compared to their healthy controls.~Researchers examined the strength of gluteus medius (G Med) muscle function in patients with LBP compared to non-LBP controls. The study reported that G Med muscle strength was decreased and several trigger points were developed but there were unclear results on fatigability, activity level, and macromorphology compared to healthy individuals.~It was evident, however, that the slight increase in muscle thickness of certain local and global muscles during contraction in the NSCLBP group compared to a healthy group when examined by ultrasonography could be an indicator that the strengthening of the multifidus, the transversus abdominis, and the G Med prevents the occurrence of LBP.~Exercise therapy is one of the inexpensive tools addressing pain relief and disability management in patients with subacute, chronic low back pain (CLBP) compared to usual care, according to the recently published systematic review.~Various types of exercise interventions should be used by physical therapists in the management of CLBP, as recommended by the American Physical Therapy Association (APTA) guidelines for clinical practice.~In a study by Mendis & Hides (2016), they demonstrated lumbar-pelvic muscle imbalance in LBP and improvement in sartorius and G Med muscle size when motor training interventions were applied in non-weight-bearing and weight-bearing positions during treatment of LBP.~A recent study evaluated the effectiveness of adding specific hip strengthening exercises to a conventional rehabilitation program in the management of LBP patients. The results of the systematic review revealed that hip strengthening exercises could reduce pain and disability in these patients.~At the same time, there is still a knowledge gap regarding the effect of G Med strengthening exercise specifically on pain and disability levels in patients with NSCLBP and muscle macromorphology (thickness), as recommended in several recent systematic reviews.
To study the effect of adding selected G Med muscle strengthening exercises to the APTA-guided program on pain, disability level, and G Med macromorphology in patients with NSCLBP.