Where Did Trigger Point Therapy Originate?

Historical Roots of Trigger Point Concepts

The concept that discrete, hyperirritable spots within muscle could produce local and referred pain has a history substantially longer than is commonly appreciated. John Kellgren, working in the 1930s and 1940s at University College Hospital London, conducted systematic experiments injecting hypertonic saline into muscles and ligaments and mapping the resulting referred pain patterns — producing some of the earliest scientific documentation of referred pain from musculoskeletal structures. His work demonstrated that pain arising from muscle could be perceived at sites remote from the source, and that the referred patterns were consistent across subjects.

The term and theoretical framework that would become the dominant clinical model, however, was developed primarily by Dr. Janet Travell, a physician who became physician to Presidents Eisenhower and Kennedy. From the 1940s onward, Travell developed detailed charts of trigger point locations and their associated referred pain patterns, culminating in her monumental two-volume textbook Myofascial Pain and Dysfunction: The Trigger Point Manual, written with David Simons and published in its first volume in 1983. This work became the foundational clinical reference for trigger point practice and gave the field its systematic anatomical architecture.

Travell and Simons: The Model Defined

Travell and Simons defined a myofascial trigger point (MTrP) as a hyperirritable spot in a taut band of skeletal muscle that is painful on compression, stretch, overload, or contraction of the tissue, and that gives rise to characteristic referred pain, tenderness, and autonomic phenomena. Their model proposed a pathophysiological mechanism involving a dysfunctional motor endplate — an excess release of acetylcholine at the neuromuscular junction leading to sustained sarcomere contraction, local energy crisis (due to elevated metabolic demand and impaired microcirculation), and sensitisation of peripheral nociceptors. This "integrated hypothesis" remains the most widely cited theoretical model for trigger point formation.

The referred pain patterns documented by Travell and Simons — for every muscle of the body — remain the practical core of trigger point clinical practice. Their detailed documentation of predictable referral patterns from specific muscles has enabled clinicians to work backwards from a patient's reported pain location to potential source muscles, even when those muscles are not locally symptomatic.

The Contemporary Scientific Debate

Despite decades of clinical use and the strong face validity of the trigger point model, its scientific status remains contested. The fundamental challenge is reliable identification: multiple studies examining inter-rater reliability for trigger point location using palpation alone have produced disappointing results, with agreement rates only marginally better than chance for some parameters. If two experienced clinicians cannot reliably locate the same trigger point in the same patient, the structural reality of the discrete "hyperirritable spot" is called into question.

Magnetic resonance elastography and ultrasound studies have produced mixed evidence regarding the structural correlates of trigger points. Some research has identified areas of altered tissue stiffness consistent with palpable taut bands; other studies have failed to replicate this. The evidence for the motor endplate hypothesis is partially supported — elevated spontaneous electrical activity (SEA) has been found at trigger point sites by several investigators — but the causal chain from endplate dysfunction to sustained contracture to referral has not been fully established.

The most productive clinical interpretation is to consider trigger point therapy as a useful clinical framework for organising soft tissue assessment and treatment, while recognising that the precise mechanism by which it produces benefit likely involves neurobiological pain modulation, altered motor patterns, and contextual effects, rather than the discrete structural pathology originally proposed by Travell and Simons.

Evolution and Current Practice

Modern trigger point practice has evolved substantially from its origins. Dry needling — the application of filiform acupuncture needles to trigger points without injection of any substance — emerged as an extension of Travell's original injection techniques, and has been subject to considerably more controlled research than manual trigger point therapy. The current evidence base for dry needling shows consistent short-term effects on pain and pressure pain threshold, though effect sizes vary considerably across populations and conditions. The neurobiological mechanisms are thought to include local tissue disruption at the needling site, activation of descending inhibitory systems, and disruption of sensitised nociceptive input patterns.