Background and Objectives: The aging population and the COVID-19 pandemic have led to a rise in severe conditions, including musculoskeletal (MSK) disorders. Although MSK conditions are often managed in primary care, they may sometimes mask serious illnesses requiring urgent diagnosis. The red flag (RF) concept is essential for identifying signs and symptoms of potentially severe disease. However, RF criteria vary across clinical guidelines and lack consistency. With the growing role of direct access to physiotherapy—bypassing physician referral—physiotherapists must develop strong differential diagnostic skills to identify serious pathologies that mimic MSK disorders. This review aims to systematically map how RFs are defined in MSK clinical practice guidelines (CPGs), supporting the move toward a standardized definition for clinical and research use. Materials and Methods: A comprehensive literature search was conducted in PubMed, Web of Science, Scopus, and Cochrane databases. Included studies were CPGs and systematic reviews (SRs) of CPGs addressing MSK disorders and incorporating the RF concept. Data extraction followed a rigorous process, and RF definitions were synthesized and compared in table format. Results: Out of thirteen-thousand three-hundred and ninety-three articles identified, fourteen met inclusion criteria (seven CPGs and seven SRs of CPGs), spanning both physiotherapy and medical fields. All definitions described RFs as signs or symptoms indicating possible serious pathology requiring further investigation or referral. Some definitions referred broadly to “patterns of signs or symptoms”, while others offered more precise criteria. Conclusions: This review highlights the lack of a standardized RF definition in MSK care, leading to inconsistencies in clinical decision-making and diagnosis. To improve patient safety and guide clinicians—especially in direct-access contexts—a unified, internationally recognized definition of RFs is needed in future guidelines.

Background: Pelvic girdle pain (PGP) is described in the literature as a subgroup of low back pain (LBP), characterized by pain localized between the posterior iliac crest and the gluteal fold, particularly near the sacroiliac joints. This condition can manifest in different forms non-specific PGP, occurring during pregnancy or postpartum (pregnancy-related PGP), which represents the most prevalent form and non-pregnancy-related PGP, resulting from mechanical alterations caused by trauma or microtrauma. Specific PGP, associated with identifiable causes such as fractures, infections, or arthritis. Over the years, research has focused on identifying the most effective approaches for managing this condition and addressing its associated biopsychosocial impairments. The aim of this narrative review is to determine the types of motor control exercises (MCEs) used to reduce short-term pain in patients with PGP and to assess whether these exercises are designed in accordance with the principles of motor control (MC) theories. Methods: A narrative review was conducted through searches in various medical and rehabilitation databases, including MEDLINE (via PubMed), PEDro, Scopus, and Web of Science. The inclusion criteria of the review encompassed case studies, case reports, editorials, original research articles, randomized controlled trials (RCTs), and systematic reviews (SRs). Results: Six articles met the eligibility criteria, comprising two SRs and four RCTs, all of which were included in the qualitative analysis. Among these, two studies examine MCEs for non-pregnancy-related PGP, while all the other studies focus on pregnancy-related PGP. The exercises described focused on lumbar–pelvic stabilization or deep spinal muscle activation. Among the six included studies, five did not report statistically significant changes in pain outcomes, while only one study demonstrated a statistically significant improvement. Conclusions: The analysis highlighted that the exercises currently employed are generally unspecific and not systematically structured according to the principles outlined in MC theories. The available evidence, combined with the incorrect design of these exercises, does not allow for definitive conclusions regarding the efficacy of MCEs in reducing short-term pain in patients with both pregnancy-related and non-pregnancy-related PGP.