Assessment of resistance torque and resultant muscular force during Pilates hip extension exercise and its implications to prescription and progression.

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 (Γ(R)) during hip extension (HE) exercises performed on the Pilates Cadillac. To perform a biomechanic analysis of the Γ(R) 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 Γ(R), the muscle torque (Γ(M)) 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 Γ(R) and FM(R) presented a similar behavior during all situations; however, the maximum Γ(R) 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.

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.

Atividade elétrica dos músculos oblíquos externos e multífidos durante o exercício de flexoextensão do quadril realizado no Cadillac com diferentes regulagens de mola e posições do indivíduo / Electrical activity of external oblique and multifidus muscles during the hip flexion-extension exercise performed in the Cadillac with different adjustments of springs and individual positions

CONTEXTUALIZAÇÃO: Apesar do amplo uso do Pilates na Fisioterapia, há poucos estudos que avaliaram a ativação elétrica dos músculos nos exercícios. OBJETIVO: Verificar a influência de diferentes regulagens de mola e posições do indivíduo sobre a ativação elétrica dos multífidos (MU) e oblíquos externos (OE) durante a flexoextensão do quadril (FEQ) no Cadillac. MÉTODOS: Oito mulheres praticantes de Pilates por seis meses realizaram 10 repetições de FEQ nas situações: mola baixa (MB), mola fixada a 30 cm do nível em que estava o indivíduo; mola alta (MA), mola fixada a 90 cm do nível em que estava o indivíduo; posição próxima (PP), distância de 10 cm da fixação da mola; posição distante (PD), distância de 30 cm da fixação da mola. Dados cinemáticos e de eletromiografia (EMG) foram coletados sincronizadamente, e os músculos monitorados bilateralmente foram os OE e os MU. Cada movimento de FEQ foi recortado em duas fases (extensão e flexão). O sinal de EMG foi calculado e normalizado usando a contração voluntária máxima (CVM). O Wilcoxon test foi usado para investigar diferenças entre as situações (p<0,05). RESULTADO: Os músculos MU apresentaram valores de ativação muscular de 10 a 20 por cento da CVM, sendo os maiores valores observados na MA e na PD. Para os OE, valores de ativação de 20 a 45 por cento da CVM foram encontrados, com os maiores valores obtidos na MB e na PP. CONCLUSÃO: Os músculos OE e MU apresentaram uma ativação elétrica distinta durante as diferentes regulagens de mola e posições dos indivíduos avaliados.

BACKGROUND: Despite of the widepread use of Pilates in Physical Therapy, there are few studies that have assessed the muscle electrical activation during Pilates exercises. OBJECTIVE: Verify the influence of different spring adjustments and individual positions on the electrical activation of multifidus (MU) and oblique external (OE) muscles during hip flexion-extension (HFE) exercise on the Cadillac. METHODS: Eight women practicing Pilates exercises for at least six months performed 10 repetitions of HFE in the following situations: Lower Spring, spring fixed at 30 cm in relation to level which the individuals were positioned. Higher Spring, spring fixed at 90 cm in relation to level which the individuals were positioned. Near Position, distance of 10 cm from the fixed spring. Distant Position, distance of 30 cm from the fixed spring. Kinematic and eletromyographic data (EMG) were collected simultaneously and the MU and OE muscles were monitored. Each movement of HFE was splitted in two phases (extension and flexion). The EMG signal was calculated and normalized using the maximal voluntary contraction (MVC). The Wilcoxon test was used to investigate differences between the situations (p<0.05). RESULTS: MU muscle presented muscle activation values ranging from 10 to 20 percent MVC, and the highest muscle activation in the lower spring and in the near position. OE muscles presented muscle activation values ranging from 20 to 45 percent MVC, and the highest values in the higher spring and in the distant position. CONCLUSION: MU and OE muscles presented a distinct electrical activation during different available spring adjustments and individual positions.

Electrical activity of external oblique and multifidus muscles during the hip flexion-extension exercise performed in the Cadillac with different adjustments of springs and individual positions.

BACKGROUND: Despite of the widepread use of Pilates in Physical Therapy, there are few studies that have assessed the muscle electrical activation during Pilates exercises. OBJECTIVE: Verify the influence of different spring adjustments and individual positions on the electrical activation of multifidus (MU) and oblique external (OE) muscles during hip flexion-extension (HFE) exercise on the Cadillac. METHODS: Eight women practicing Pilates exercises for at least six months performed 10 repetitions of HFE in the following situations: Lower Spring, spring fixed at 30 cm in relation to level which the individuals were positioned. Higher Spring, spring fixed at 90 cm in relation to level which the individuals were positioned. Near Position, distance of 10 cm from the fixed spring. Distant Position, distance of 30 cm from the fixed spring. Kinematic and eletromyographic data (EMG) were collected simultaneously and the MU and OE muscles were monitored. Each movement of HFE was splitted in two phases (extension and flexion). The EMG signal was calculated and normalized using the maximal voluntary contraction (MVC). The Wilcoxon test was used to investigate differences between the situations (p < 0.05). RESULTS: MU muscle presented muscle activation values ranging from 10 to 20 % MVC, and the highest muscle activation in the lower spring and in the near position. OE muscles presented muscle activation values ranging from 20 to 45% MVC, and the highest values in the higher spring and in the distant position. CONCLUSION: MU and OE muscles presented a distinct electrical activation during different available spring adjustments and individual positions.