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Musculoskeletal biomechanics: articles, publications, and clinical model
Mauro Lastrico, PT — Laura Manni, PT
The AIFIMM biomechanical model is an analytical and systemic clinical framework for interpreting pain, dysfunction, and joint and spinal pathologies. This page collects scientific articles, theoretical foundations, clinical applications, downloadable PDFs, and international publications.
Theoretical foundations of the model Articles defining the physical and biomechanical principles.
Systemic musculoskeletal biomechanics: a...
Free e-book: physical and clinical foundations of the AIFIMM biomechanical model
Mauro Lastrico, PT — Laura Manni, PT
This e-book presents the theoretical and clinical principles underlying the analytical and systemic biomechanical model developed by AIFIMM — Institute of Applied Musculoskeletal Biomechanics.
It does not describe techniques or protocols. It provides the conceptual framework that explains why muscles shorten, how shortening alters joint mechanics, and why symptoms recur...
The iliopsoas: why it shortens, why stretching fails, and what to do instead
Mauro Lastrico, PT — Giuliano Chiri, PT
The most widespread exercise for lengthening the iliopsoas — hip extension in a rear lunge — is a biomechanical misconception. The psoas inserts from T12 to L4: when the femur extends, the lumbar spine cannot be fixed because all muscles with direct spinal insertion are co-agonists in increasing lordosis. The...
Diaphragm and abdominal breathing: when "breathing with the diaphragm" is the problem, not the solution
Mauro Lastrico, PT — Giuseppe Macrì, PT
Abdominal breathing observed in many patients may be the sign of muscular shortening preventing costal expansion — not the sign of good diaphragmatic breathing. The diaphragm has four points of action: two on the ribs and two on the spine. When costal expansion is blocked, the diaphragm acts on the...
Systemic musculoskeletal biomechanics: a clinical model based on vector analysis
Mauro Lastrico, PT — Laura Manni, PT
Systemic musculoskeletal biomechanics is a clinical model that interprets joint and spinal dysfunctions as the result of progressive shortening of myofascial units. Through vector analysis of muscular forces, it identifies the mechanical causes of pain, stiffness, and recurrence, and guides treatment based on verifiable physical laws.
The clinical problem
Chronic...
Isometric contractions, muscle length, and stretching: what the evidence says
Mauro Lastrico, PT — Laura Manni, PT
Active exercise is the intervention with the highest level of evidence for musculoskeletal pathologies. Isometric contractions performed at longer muscle lengths produce superior adaptations in hypertrophy, strength, and tendon structure. Static stretching increases range of motion but through a predominantly perceptual mechanism, without producing stable structural adaptations. This article collects...
How muscle shortening generates joint conflict: the role of connective tissue
Mauro Lastrico, PT — Laura Manni, PT
Muscle shortening is a physical phenomenon governed by the elastic properties of connective tissue. Understanding the mechanism that produces it allows the identification of the mechanical cause of joint conflicts, spinal compressions, and alterations of physiological joint sequencing.
The attached PDF document, available for free download, develops the complete physical-mathematical...
Do antigravity muscles really oppose gravity?
Mauro Lastrico, PT — Laura Manni, PT
So-called antigravity muscles do not oppose gravity. The weight force is constantly balanced by the ground counterforce. The task of the muscular system is to align segmental centres of mass along the vertical of the counterforce, distributing loads evenly across joints and the spinal column. When muscular organisation is altered,...
Why joint conflict develops: vector analysis of muscular forces
Mauro Lastrico, PT — Laura Manni, PT
Every joint malalignment, in the absence of specific pathology, is the result of unbalanced muscular forces. Vector analysis identifies which muscles are responsible for the alteration of physiological joint sequencing and predicts the compensatory patterns the system develops in response.
The attached PDF document, available for free download, develops the...
Cervical hyperlordosis, straightening, and forward head: biomechanical causes and disc compressions
Mauro Lastrico, PT — Laura Manni, PT
Cervical hyperlordosis, cervical spine straightening, and forward head projection are predictable biomechanical patterns generated by shortening of the muscles acting on the cranio-cervico-thoracic segment. Vector analysis identifies which muscles are responsible for each pattern, how anterior neck muscles undergo action reversal, and which disc compressions result.
The attached PDF document,...
Thoracic kyphosis, lumbar lordosis, and spinal straightening: vector analysis in the sagittal plane
Mauro Lastrico, PT — Laura Manni, PT
Thoracic hyperkyphosis, flat back, lumbar hyperlordosis, and lumbar straightening are biomechanical patterns predictable through vector analysis of the muscles acting on the spine in the sagittal plane. This article analyses the thoracic segment T4–T6, the thoraco-lumbo-sacral segment T7–S1, and the pelvis, identifying muscular dominances, systemic compensation mechanisms, and the resulting...
The hyoid bone in cranio-cervical biomechanics: a point of mechanical convergence and force redistribution
Mauro Lastrico, PT — Laura Manni, PT
The hyoid bone is entirely suspended in the anterior region of the neck, with no articulations to other skeletal segments. Its position in space is determined exclusively by the balance of muscular forces converging on it. This characteristic makes it a mechanical node of the cranio-cervico-scapular system: a point of...
Vertebral rotation and radicular compression: vector analysis in the frontal and rotatory plane
Mauro Lastrico, PT — Laura Manni, PT
Vertebral rotation is produced by asymmetric shortening of bilateral muscles. The vertical components of muscular forces compress the intervertebral discs, while rotation of the vertebral bodies reduces the intervertebral foramen on the side opposite the convexity, generating radicular compression. Vector analysis in the frontal plane identifies the responsible muscles and...
Scoliosis: vertebral rotation, lateral deviation, and biomechanical intervention criteria
Mauro Lastrico, PT — Laura Manni, PT
Scoliosis can be analysed through the same vector principles applied to vertebral deviations in the frontal plane. Analysis of the relationship between rotation and vertebral deviation provides an interpretative criterion for evaluating response to muscular treatment. Once established, scoliosis develops self-perpetuating mechanisms involving both convex-side and concave-side muscles.
The attached...
Cranio-cervico-mandibular disorders: when jaw pain comes from the neck and vice versa
Mauro Lastrico, PT — Laura Manni, PT
Temporomandibular joint dysfunction is rarely a primary cause. In the majority of cases, it is the final manifestation of alterations originating in other body districts. Biomechanical analysis identifies three pathways through which cranio-cervico-mandibular disorders develop and provides criteria for distinguishing whether the problem is dental, sensory, or muscular — a...
Shoulder, elbow, and epicondylitis: vector analysis of the upper limb
Mauro Lastrico, PT — Laura Manni, PT
Shoulder pain, scapulohumeral impingement, and epicondylitis can derive from muscular imbalances identifiable through vector analysis. The shoulder is a system of six interconnected articular relationships in which the scapula is constantly adducted, the humerus is dominated by the internal rotators, and joint conflict is the predictable mechanical consequence of converging...
Knee and hip: valgus, varus, hyperextension, and intra-articular compressions
Mauro Lastrico, PT — Laura Manni, PT
The knee is the point of convergence of forces arising from the hip and the foot. Pathological patterns follow a logical progression determined by intensification of muscular shortening: from initial hyperextension and internal rotation to flexion and external rotation in the more advanced phases. Vector analysis identifies the muscles responsible...
Flat foot, cavus foot, and hallux valgus: vector analysis of the medial arch, anterior arch, and hallux
Mauro Lastrico, PT — Laura Manni, PT
The medial plantar arch is the only articular structure in the body in which all muscular vectors act in summation in favour of support, without antagonism. This engineering principle reflects the need to support the entire body weight. Flat foot, cavus foot, anterior arch collapse, and hallux valgus are patterns...
Pain neuroscience and muscle shortening: three systems, one final effector
Mauro Lastrico, PT — Laura Manni, PT
Muscle shortening is not a random phenomenon. It is the result of precise physiological mechanisms leading to increased basal tone. When this increase persists over time, it progressively involves the connective tissue component of the muscle fibre, producing the permanent residual shortening observed in segmental analysis. Three different systems use...
Beyond muscle chains: the musculoskeletal system as a complex system
Mauro Lastrico, PT — Laura Manni, PT
The concept of "muscle chains" describes a real phenomenon — muscles operate in interconnected systems — but explains it with a linear model that does not account for what is observed clinically: why small dysfunctions generate widespread symptoms, why compensations are often unpredictable, and why the body develops adaptive strategies...
Why the symptom returns: clinical reasoning in musculoskeletal pain diagnosis
Mauro Lastrico, PT — Laura Manni, PT
When a musculoskeletal symptom returns after treatment, the cause lies outside the treated segment. In the presence of a mechanical symptom, four recurrent constants are observed: intra-articular mechanical conflict, asymmetric vector shortening, systemic misalignment, and systemic distribution of shortening. The distinction between primary and secondary shortening determines therapeutic strategy and...
Musculoskeletal assessment: why "correcting posture" is a conceptual error
Mauro Lastrico, PT — Laura Manni, PT
The spatial configuration of the body is not an independent variable to be judged in aesthetic or normative terms. It is the observable resultant of a system of forces in dynamic equilibrium. Classifying a configuration as "correct" or "incorrect" based on visible form constitutes a methodological error. Assessment must focus...
Why muscle strengthening alone does not correct joint alignment
Mauro Lastrico, PT — Laura Manni, PT
Strengthening a subdominant muscle cannot modify joint alignment as long as the dominant vector opposes a Resistant Force greater than the Work Force the subdominant muscle can express. Strengthening a muscle in a vectorially unbalanced system consolidates the compensatory pattern instead of correcting it. Reducing Resistant Force in shortened muscles...