The Relation of Paraspinal Muscles and Degenerative Lumbar Spondylolisthesis / 대한정형외과연구학회지

OBJECTIVES: To evaluate the cross-sectional area (CSA) and the moment arm length (MAL) of the paraspinal muscles in the degenerative lumbar spondylolisthesis patients compared to the matched control patients, which is through contribution to the stability of the back. MATERIALS AND METHODS: We studied a comprised of 25 degenerative lumbar spondylolisthesis on L4/5 patients and a controlled group with 42 chronic lower back pain patients. In both groups, we measured body mass index (BMI, kg/m2). On the standing lateral radiographs, we measured the total lumbar lordosis, and segmental lumbar lorodosis using Cobb's methods. We measured the degree of slippage by Meyerding classification. The CSA of erector spinae (CSA) and CSA of psoas were measured at the L4/5 level by using the MRI. The statistical analysis were performed to know the relationship between the CSA and the MAL of erector spinae, and the BMI. Multifidus and erector spinae atrophy were evaluated at the L4/5 level and the degree of fatty atrophy was estimated using three grades : mild, moderate, and severe. RESULTS: The patient group and the controlled group BMI (kg/m2) were 25.27+/-3.8 and 24.47+/-3.24. In patient group, Meyerding classification grade I was 92%. Total lumbar lordosis and each segmental lordosis were measured mean angle 44.54degrees(24.9degrees~70.4degrees), and each 9.23degrees(L3/4), 10.27degrees(L4/5), 18.81degrees(L5/S1). Pearson's rho indicated a positive association between the CSA and BMI (rho=0.603, p= 0.001), between the CSA of psoas and BMI (rho=0.445, p=0.026), and between the CSA and MAL (rho=0.627, p=0.001) in the degenerative lumbar spondylolisthesis patients. In terms of the CSA versus MAL, there was a positive association in the both groups (rho=0.627, p=0.001, MAL=0.0008 CSA+/-5.293 in the degenerative lumbar spondylolisthesis group; rho=0.812, p=0.000, MAL=0.001 CSA+/-5.245 in the control group with using linear regression analysis). Independent t-test revealed that both groups had statistically different mean values (p=0.038) in terms of the CSA. Proportion of fat deposits in the multifidus and erector spinae muscle at the L3/4 level were all mild grades. CONCLUSION: The patients with degenerative lumbar spondylolisthesis had atrophied erector spinal muscles, which means harmful because of the poor compensation for the lower back load and poor assists to the lumbar stability. This suggests that the biomechanical factor of the muscles influence to the lumbar disability.

Análise do torque de resistência e da força muscular resultante durante exercício de extensão de quadril no Pilates e suas implicações na prescrição e progressão / Assessment of resistance torque and resultant muscular force during Pilates hip extension exercise and its implications to prescription and progression

CONTEXTUALIZAÇÃO: A análise da mecânica externa dos exercícios de Pilates e da biomecânica das articulações pode subsidiar a prescrição de exercícios na reabilitação. OBJETIVOS: Avaliar o comportamento do torque de resistência (ΓR) do exercício de extensão de quadril (EQ) realizado no Cadillac; realizar uma análise biomecânica a partir do comportamento do ΓR e das distâncias perpendiculares médias ponderadas (DPMPs) para estimar a força muscular resultante (FM R) dos extensores e flexores e propor critérios mecânicos para progressão do exercício de EQ realizado no Cadillac. MÉTODOS: Catorze praticantes de Pilates realizaram EQ no aparelho Cadillac em quatro situações em ordem aleatorizada - usando duas molas (vermelha e azul) fixadas em duas posições (alta e baixa). As posições angulares foram coletadas por meio de eletrogoniometria. Para o cálculo do ΓR, torque muscular (ΓM) e da FM R foram usados diagramas de corpo livre e equações de movimento. Os valores de DPMP dos músculos flexores e extensores do quadril foram quantificados usando dados da literatura. RESULTADOS: O ΓR e a FM R apresentaram comportamentos semelhantes em todas as situações, entretanto os valores máximos de ΓR não ocorrem na mesma posição articular que a FM R máxima. A DPMP dos flexores de quadril apresentou um comportamento crescente-decrescente, com máximo próximo aos 55º de flexão, enquanto os extensores de quadril apresentaram comportamento semelhante, com máximo próximo aos 25º de flexão. CONCLUSÃO: A análise biomecânica do exercício e a avaliação das características mecânicas associadas à articulação do quadril podem ser usadas como critérios objetivos de prescrição e progressão do exercício de EQ no Pilates.

BACKGROUND: The understanding of the external mechanics of Pilates exercises and the biomechanics of the joints may guide the prescription of rehabilitation exercises. OBJECTIVES: To evaluate the resistance torque (ΓR) during hip extension (HE) exercises performed on the Pilates Cadillac. To perform a biomechanic analysis of the ΓR and the weighted mean moment arm (WMMA) in order to calculate the resultant muscle force (FM R) of the hip extensors and flexors. To present a mechanical criteria for progression of HE exercise on the Pilates Cadillac. METHODS: Fourteen participants performed HE exercises on the Cadillac in four randomly assigned situations - using two springs (blue and red), which were attached in two positions (high and low). Angular positions were measured using an electrogoniometer. In order to calculate ΓR, the muscle torque (ΓM) and FM R, free-body diagrams and movement equations were used. The WMMA of the hip extensors and flexors were estimated from the literature. RESULTS: The ΓR and FM R presented a similar behavior during all situations; however, the maximum ΓR values did not occur at the same joint position as the FM R maximum values. The WMMA of the hip flexors presented an increased- decreased behavior with greatest values around 55º of flexion, while the hip extensors presented a similar behavior with greatest values around 25º of flexion. CONCLUSION: Biomechanic analysis of HE exercises and the evaluation of mechanical features in relation to the hip joint may be used as an objective criteria for the prescription and progression of HE exercise in Pilates.

Study on correlation between reduction loss and fixator moment arm after treatment of acromioclavicular joint dislocation using endobutton technique / 医用生物力学

Objective To study the correlation between the amount of reduction loss and the length of fixator moment arm after treating acrmioclavicular（AC）joint dislocation with the endobutton technique as viewed from mechanics. Methods 24 patients with acute AC joint dislocation were treated with the endobutton technique and made the follow-up from Mar. 2009 to Dec. 2010 in Shanghai Ninth People’s Hospital. The loss of reduction was observed by evaluating the change of distance between the coracoid and clavicle three days and six months after the operation, respectively. Meanwhile, the length from the upper endnobutton midpoint to the proximal end of clavicle (L1) and the whole length of clavicle (L) were measured and the ratio of L1/L as the moment arm of the fixator was calculated to study the correlation between reduction loss and moment arm. Results All the 24 patients received good reduction after the operation, and the distance between the coracoid and clavicle returned to normal. The average distance between the coracoid and clavicle three days and six months after the operation was (28.2±3.9) and (29.5±4.1) mm, respectively. The amount of average reduction loss was (1.3±1.2) mm. The average moment arm was 0.79±0.03. There was a significant negative correlation between the reduction loss and moment arm with the correlation coefficient -0.498(P＜0.05). Conclusions For the treatment of AC joint dislocation using endobutton technique, the position of the endobutton is closely related with the loss of reduction postoperatively. The shorter the moment arm, the greater the loss of reduction would be. The proper moment arm should be around 0.80.

JCS-based method on coordinate transformation of attachment points between muscle and bone / 医用生物力学

Objective In order to avoid potential injuries imposed to human body,it could be feasible to use the musculoskeletal models which can be reconstructed from the cadaver color cryosection(CCC)images,computerized tomography(CT)images,magnetic resonance(MR)images or other images to analyze the dynamic properties of muscles in vivo during human movement.Mothod We reconstruct the lower limb musculoskeletal model and define the uniform ioint coordinate system(JCS)on the model and the subject.The coordinate transformation of the muscle attachment points both on the model and the subject is described in detail.Results The length and the moment arm of the biceps femoris(short head)during knee flexion are calculated and analyzed.Conclusion This method plays an important role in improving the kinematics and dynamic simulation and the muscle force estimation.

JCS-based method on coordinate transformation of attachment points between muscle and bone / 医用生物力学

Objective In order to avoid potential injuries imposed to human body,it could be feasible to use the musculoskeletal models which can be reconstructed from the cadaver color cryosection(CCC)images,computerized tomography(CT)images,magnetic resonance(MR)images or other images to analyze the dynamic properties of muscles in vivo during human movement.Mothod We reconstruct the lower limb musculoskeletal model and define the uniform ioint coordinate system(JCS)on the model and the subject.The coordinate transformation of the muscle attachment points both on the model and the subject is described in detail.Results The length and the moment arm of the biceps femoris(short head)during knee flexion are calculated and analyzed.Conclusion This method plays an important role in improving the kinematics and dynamic simulation and the muscle force estimation.

JCS-based method on coordinate transformation of attachment points between muscle and bone / 医用生物力学

Objective In order to avoid potential injuries imposed to human body,it could be feasible to use the musculoskeletal models which can be reconstructed from the cadaver color cryosection(CCC)images,computerized tomography(CT)images,magnetic resonance(MR)images or other images to analyze the dynamic properties of muscles in vivo during human movement.Mothod We reconstruct the lower limb musculoskeletal model and define the uniform ioint coordinate system(JCS)on the model and the subject.The coordinate transformation of the muscle attachment points both on the model and the subject is described in detail.Results The length and the moment arm of the biceps femoris(short head)during knee flexion are calculated and analyzed.Conclusion This method plays an important role in improving the kinematics and dynamic simulation and the muscle force estimation.

JCS-based method on coordinate transformation of attachment points between muscle and bone / 医用生物力学

Objective In order to avoid potential injuries imposed to human body, it can be feasible to use the musculoskeletal models which can be reconstructed from the cadaver color cryosection (CCC) images, computerized tomography (CT) images, magnetic resonance (MR) images or other images to analyze the dynamic properties of muscles in vivo during human movement. Methods We reconstruct the lower limb musculoskeletal model and define the uniform joint coordinate system (JCS) on the model and the subject. The coordinate transformation of the muscle attachment points both on the model and the subject is described in detail. Results The length and the moment arm of the biceps femoris (short head) during knee flexion are calculated and analyzed. Conclusion This method plays an important role in improving the kinematics and dynamic simulation and the muscle force estimation.