Exploratory factor analysis for differentiating sensory and mechanical variables related to muscle-tendon unit elongation

ABSTRACT Background Stretching exercises are able to promote adaptations in the muscle-tendon unit (MTU), which can be tested through physiological and biomechanical variables. Identifying the key variables in MTU adaptations is crucial to improvements in training. Objective To perform an exploratory factor analysis (EFA) involving the variables often used to evaluate the response of the MTU to stretching exercises. Method Maximum joint range of motion (ROMMAX), ROM at first sensation of stretching (FSTROM), peak torque (torqueMAX), passive stiffness, normalized stiffness, passive energy, and normalized energy were investigated in 36 participants during passive knee extension on an isokinetic dynamometer. Stiffness and energy values were normalized by the muscle cross-sectional area and their passive mode assured by monitoring the EMG activity. Results EFA revealed two major factors that explained 89.68% of the total variance: 53.13% was explained by the variables torqueMAX, passive stiffness, normalized stiffness, passive energy, and normalized energy, whereas the remaining 36.55% was explained by the variables ROMMAX and FSTROM. Conclusion This result supports the literature wherein two main hypotheses (mechanical and sensory theories) have been suggested to describe the adaptations of the MTU to stretching exercises. Contrary to some studies, in the present investigation torqueMAX was significantly correlated with the variables of the mechanical theory rather than those of the sensory theory. Therefore, a new approach was proposed to explain the behavior of the torqueMAX during stretching exercises.

The effects of stretching on the flexibility, muscle performance and functionality of institutionalized older women

Stretching has been widely used to increase the range of motion. We assessed the effects of a stretching program on muscle-tendon length, flexibility, torque, and activities of daily living of institutionalized older women. Inclusion/exclusion criteria were according to Mini-Mental State Examination (MMSE) (>13), Barthel Index (>13) and Lysholm Scoring Scale (>84). Seventeen 67 ± 9 year-old elderly women from a nursing home were divided into 2 groups at random: the control group (CG, N = 9) participated in enjoyable cultural activities; the stretching group (SG, N = 8) performed active stretching of hamstrings, 4 bouts of 1 min each. Both groups were supervised three times per week over a period of 8 weeks. Peak torque was assessed by an isokinetic method. Both groups were evaluated by a photogrammetric method to assess muscle-tendon length of uni- and biarticular hip flexors and hamstring flexibility. All measurements were analyzed before and after 8 weeks by two-way ANOVA with the level of significance set at 5 percent. Hamstring flexibility increased by 30 percent in the SG group compared to pre-training (76.5 ± 13.0° vs 59.5 ± 9.0°, P = 0.0002) and by 9.2 percent compared to the CG group (76.5 ± 13.0° vs 64.0 ± 12.0°, P = 0.0018). Muscle-tendon lengths of hip biarticular flexor muscles (124 ± 6.8° vs 118.3 ± 7.6°, 5.0 ± 7.0 percent, P = 0.031) and eccentric knee extensor peak torque were decreased in the CG group compared to pre-test values (-49.4 ± 16.8 vs -60.5 ± 18.9 Nm, -15.7 ± 20 percent, P = 0.048). The stretching program was sufficient to increase hamstring flexibility and a lack of stretching can cause reduction of muscle performance.

Importance of the different posterolateral knee static stabilizers: biomechanical study

PURPOSE: The purpose of this study was to evaluate the relative importance of the different static stabilizers of the posterolateral corner of the knee in cadavers. METHODS: Tests were performed with the application of a varus and external rotation force to the knee in extension at 30 and 60 degrees of flexion using 10 cadaver knees. The forces were applied initially to an intact knee and then repeated after a selective sectioning of the ligaments into the following: section of the lateral collateral ligament; section of the lateral collateral ligament and the popliteofibular complex; and section of the lateral collateral ligament, the popliteofibular complex and the posterolateral capsule. The parameters studied were the angular deformity and stiffness when the knees were submitted to a 15 Newton-meter varus torque and a 6 Newton-meter external tibial torque. Statistical analysis was performed using the ANOVA (Analysis of Variance) and Tukey's tests. RESULTS AND CONCLUSION: Our findings showed that the lateral collateral ligament was important in varus stability at 0, 30 and 60 degrees. The popliteofibular complex was the most important structure for external rotation stability at all angles of flexion and was also important for varus stability at 30 and 60 degrees. The posterolateral capsule was important for varus stability at 0 and 30 degrees and for external rotation stability in extension. Level of evidence: Level IV (cadaver study).

Lesiones del subescapular. Anatomia, clinica, clasificacion y tratamiento / Subscapular lesion. Anatomy, clinical features, classification and treatment

Las lesiones del subescapular son lesiones de difícil diagnóstico en especial las parciales por su asociación junto con la raiz del bíceps y supraespinosas mínimas por eso que algunos autores las denominan lesiones "escondidas". Esa es la razón por lo cual en esta actualización repasamos su anatomía, semiología junto con los métodos diagnósticos. La reparación artroscópica es posible utilizando ópticas de 70 grados junto con adecuada movilización por medio de 2 portales anteriores y accesorios que permiten mantener tensión sobre el tendón y liberar de la zona ciega que es la zona ubicada debajo del ecuador glenoideo para su ulterior fijación. Los resultados son difíciles de comparar es por ello que repasamos las clasificaciones lesionales y los metodos evaluativos a fin de mostrar criterios que ayuden a unificar en una sola idea estas distintos criterios existentes.

Características anatómicas del tendón extensor accesorio del dedo anular, procedente del músculo extensor del dedo mínimo / Anatomical characteristics of the accessory extensor tendon of the ring finger, originating from the extensor digiti minimi muscle

El músculo extensor del dedo mínimo es una larga y estrecha lámina muscular que se origina en el epicóndilo lateral del húmero, en el tendón extensor común, insertándose, generalmente, a través de dos cintillas tendinosas, en la expansión extensora del dedo mínimo. A veces, emite un tendón accesorio para el dedo anular.El objetivo del presente estudio fue conocer la incidencia, disposición y trayecto de este tendón accesorio. Se estudiaron 60 piezas de miembros superiores, fijadas en formaldehído al 10 por ciento, correspondientes a cadáveres de individuos brasileños, adultos, de ambos sexos. El tendón accesorio fue encontrado en 7 manos (11,7 por ciento de los casos). La presencia de ese tendón tiene importancia funcional y clínico-quirúrgica, pues en casos de lesiones en el dorso de la mano que afecten a los tendones del músculo extensor de los dedos, este tendón accesorio podría establecerse como una forma alternativa en la recuperación del movimiento de la extensión del dedo anular. Los resultados complementarán el conocimiento anatómico del conjunto de tendones que constituyen el dorso de la mano.

The extensor digiti minimi muscle originates from the posterior aspect of the lateral epicondyle of the humerus from a common tendon for the epicondilar muscles. The muscular belly is long and narrow and runs distally until it joins the ulnar side of a tendon over the radiocarpal articulation. Over the dorsum of the hand, this muscle is represented by a double tendon that insert in the extensor apparatus. Sometimes, these tendons give off an accessory tendon for the ring finger. The objective of this present study was to know the incidence, disposition and course of this accessory tendon. We are study 60 upper limbs from Brazilian adult cadavers of both sexs, fixed in formaldehyde 10%. The accessory tendon of the ring finger was found in 7 hands (11,7% of the cases). The presence of this tendon have functional and surgical importance; in extensor digitorum tendons injuries, this accessory tendon could be an alternative for recuperate the extension movement of the ring finger. Our results will complete the anatomic knowledge over the dorsal tendons of the hand.

Biomechanical properties of the biceps-labral complex submitted to mechanical stress

OBJETIVO: Determinar as propriedades biomecânicas do complexo labrum-glenóide bicipital superior submetido ao estresse mecânico contínuo ou repetitivo (repentino).

Estudo anatômico da inserção dos músculos grácil e semitendíneo / Anatomical study of the gracile and semitendinous muscles isertion

O aumento da utilização dos tendões dos músculos grácil e semitendíneo nos procedimentos de reconstrução ligamentar do joelho foi acompanhado de um aumento nas complicações provenientes da extração dos mesmos, como: lesão do ligamento colateral tibial, lesão do nervo safeno, retirada equivocada do tendão do músculo sartório, secção dos próprios tendões e aumento do tempo cirúrgico por imperícia ou desconhecimento da anatomia da região medial do joelho(1-6). Como a extração destes tendões tem sido um fator limitante em alguns procedimentos ortopédicos, realizamos este estudo dissecando 30 joelhos de cadáveres com os seguintes objetivos: localizar a inserção dos músculos grácil e semitendíneo na tíbia; verificar se existe correlação entre esta localização com a estatura do cadáver e avaliar as possíveis variações anatômicas. Observamos que a inserção do tendão do músculo grácil foi, em média, a 4,6 cm abaixo da superfície articular do joelho e a do semitendíneo foi, em média, a 7,4 cm. Existe correlação entre a estatura das pessoas e a localização destes tendões. Os músculos grácil e semitendíneo apresentam geralmente algum tipo de variação anatômica, sendo a mais frequente a inserção acessória do semitendíneo, 70 por cento, e em segundo lugar a fusão entre eles, 56 por cento.

Músculo accesorio del abductor largo del pulgar o tercer abductor / Accessory long abductor muscle of the thumb or third abductor

En el estudio de los tendones del músculo accesorio del abductor largo del pulgar, basados en la disección anatómica de 250 cadáveres adultos de raza mestiza del altiplano y valle, registramos que las variaciones anatómicas son muy frecuentes. La presencia de tendones accesorios ocurrió en todas las piezas disecadas. Este músculo constante, en nuestro medio se origina en el tercio inferior de la cara dorsal del radio, ulna y de la membrana interósea; diferenciandose del abductor largo del pulgar y del extensor corto del pulgar. Se dirige hacia abajo al nivel de la muñeca, pasa por debajo del retináculo extensor en la primera corredera osteofibrosa de la epífisis distal del radio junto con el abductor largo y extensor corto del dedo pulgar. Su inserción distal se realiza en primer metacarpiano.

In the study of the tendons of the accessory muscle of the long abductor of the thumb, based on the anatomical dissection of 250 mature cadavers of mestizo race of the highland and valley, we register that the anatomical variations are very frequent. The presence of accessory tendons happened in all the dissected pieces.This constant muscle, in our means, originates in the inferior third of the dorsal face of the radius, ulna and of the membrane interosseous; differing of the long abductor of the thumb and of the extending one short of the thumb. He she goes down, at the doll's level, it passes below the extending retináculo in the first sliding osteofibrosa of the lower extremity of the radius together with the short long and extending abductor of the thumb. Their insert distal is carried out in first metacarpal.

Measurement of the flexing force of the fingers by a dynamic splint with a dynamometer

OBJETIVO E MÉTODOS: Em virtude do desconhecimento relativo às forças que atuam em uma articulação durante o processo de reabilitação da mão, foi confeccionada uma órtese dinâmica que, acoplada a um dinamômetro, mediu, através de cálculos trigonométricos, a força (entre 0 a 600gf), flexora na articulação interfalângica proximal do terceiro dedo, a 30º, 45º, 60º e 90º de flexão. Estas medidas foram obtidas, em uma população de 40 adultos voluntários, 20 do sexo feminino e 20 do masculino, e confrontadas com idade, sexo e medidas antropométricas como estatura, envergadura e comprimento do dedo. RESULTADOS: Os resultados do estudo demonstraram que o tendão flexor é submetido à máxima força no início da flexão e que a força no tendão flexor diminui conforme aumenta o grau de amplitude articular. Observou uma relação entre o comprimento do dedo e a magnitude da força exercida no tendão durante a flexão do dedo, sendo que nos dedos mais compridos os tendões são submetidos a forças maiores. Quando comparou a estatura e envergadura com a magnitude da força aplicada no tendão flexor, observou uma relação positiva em todos os graus de flexão estudados, exceto a 30º. O sexo masculino apresentou maior força em todos os graus de amplitude articular. CONCLUSÕES: Conclui que é possível medir a força de flexão transmitida pelos tendões flexores através de uma órtese acoplada a um dinamômetro, que esta força é maior nos indivíduos do sexo masculino, com dedos mais longos, de maior altura e envergadura e que tais dados permitirão o desenvolvimento de futuros trabalhos no campo da reabilitação da mão, auxiliando pacientes portadores de lesões de tendões, retração cicatricial, deformidades e rigidez articular.

Age-related changes in human tendo calcaneus collagen fibrils

The ruptures of tendo calcaneus often occur between the age of 30 - 45 years as described by several textbooks. It is also described that some diseases and drugs are said to be responsible in the etiology; however, there are no studies related with the detailed histological structure of collagen fibrils found in the tendon in the age groups of humans. In view thereof, this study was aimed to obtain further information on the etiology and to find an answer regarding the frequency of the ruptures occurring between the age of 30 - 45 years in humans. In the study, the biopsy specimens taken from 28 patients [ages 1 - 68 year] who had undergone surgery due to tendo calcaneus ruptures or achilloplasty operation were examined by transmission electron microscope. All the specimens were prepared according to routine electron microscopic tissue preparation technique. The patients were divided into 7 age groups [1 - 9, 10 - 19, 20 - 29, 30 - 39, 40 - 49, 50 - 59, >60 years] and there were 4 patients in each group. The transverse diameters of collagen fibers were measured from the ultra thin sections and statistical analysis of the results were performed. The study was carried out in the electron microscopy laboratory of the Anatomy Department of Hacettepe University, Ankara, Turkey between January 2004 and September 2004. The diameters of the collagen fibers were higher in the 20 - 29 year-old group compared to other groups and it showed a statistically significant difference. In patients who were in the 30 - 39 year-old group or older, the diameters of the collagen fibers were lesser than the 20 - 29 year-old group. However, an increase was observed in the collagen fibril concentration of these groups. In examination of the specimens of patients who were under 20-year-old, the diameter of the collagen fibers were less than the 20 - 29 year-old group. The electron microscopic appearance of the tissue sample of a one-year-old patient had a specific organization and in this patient, both the diameters and concentration of collagen fibers were less. We believe that the decrease in the diameters of collagen fibers of 30 - 45 year-old patients who are in the active period of their life, can play a role in the etiology of the frequency of tendo calcaneus ruptures similar to other etiologic factors

O tendäo do poplíteo: estudo artroscópico do hiato poplíteo e sua correlaçäo funcional e clínica / Popliteus tendon: arthroscopic study of the popliteus hiatus space and its functional and clinical correlation

O autor faz uma exposiçäo da anatomia descritiva e artroscópica do tendäo do poplíteo e das estruturas que ocupam o espaço do hiato poplíteo, com sua correlaçäo funcional e clínica. Após examinar 100 gravaçöes em vídeo de artroscopias do hiato poplíteo, relata as lesöes encontradas e comenta sobre a importância das estruturas do sistema poplíteo na contençäo póstero-lateral do joelho

In vitro biomechanical evaluation of anterior cruciate ligament graft substitutes.

The study was undertaken to identify an isoelastic graft material for the anterior cruciate ligament (ACL). Double transducer ultrasonic pulse transmission method was employed for determining the elastic properties of normal ACL in comparison with various graft materials like the central third of the patellar tendon, semitendinosus and iliotibial band in different twisted forms. The elasticity and rigidity parameters were studied by taking ACL as being equal to 100 per cent. Our results indicated that the strength of the graft depended upon the density of the collagen bundles and elastic properties depended upon the pretensioning of the graft.

Efeitos de métodos de conservaçäo sobre conjunto miotendinoso isolado de coelho: estudo biomecânico / Effects os storage methods on the muscle tendons isolated from rabbits

Foram submetidos a ensaios mecânicos de traçäo axial 78 conjuntos miotendinosos isolados do Extensor Digitorum Longus de coelhos (CMT). Trinta e nove foram analisados a fresco e seus 39 pares foram submetidos, durante sete dias, aos seguintes métodos de conservaçäo: 1) formalina 10 por cento; 2) soluçäo isotônica de cloreto de sódio 0,9 por cento e a 4ºC; 3) embalagem em papel-alumínio e a -20ºC e 4) embalagem em papel-alumínio e a -180ºC. As variáveis estudadas foram: 1) peso do CMT - antes e depois da conservaçäo; 2) carga suportada no limite de resistência; 3) deformaçäo apresentada no limite de resistência e 4) ponto de ruptura do cinjunto, à traçäo. Discutem-se as particularidades metodológicas de ensaios mecânicos com corpos de prova biológicos (especialmente tecidos moles). Os resultados obtidos foram correlacionados com os métodos de conservaçäo utilizados. Com a metodologia empregada foi possível concluir que a formalina 10 por cento näo modifica as características mecânicas do CMT; os métodos de resfriamento e congelamento alteram significativamente as propriedades mecânicas dos conjuntos; e o ponto frágil do sistema estudado é a interface miotendinosa, proximal ou distal.

Creatine of tenotomised muscle under influence of prednisolone treatment.

The prednisolone has got a devastating effect on the creatine content of muscle when it is tenotomised. In non-tenotomised muscle, prednisolone reduces the creatine content. The reduction of creatine content in prednisolone treated muscle which are tenotomised is due to perhaps the catabolic effect of glucocorticoid analogue on muscle protein together with inactivity of the muscle.