Efeitos da vibração mecânica de corpo inteiro sobre parametros neuromusculares e funcionais em mulheres osteopênicas na pós-menopausa

Abstract

Mechanical loading stimulation of bone with physical exercise has been described in the literature as an important non-pharmacological method to prevent and develop the musculoskeletal system. Mechanical stimulation with low intensity and low frequency vibration has been evaluated as a new, effective and safe way to improve muscle strength and bone mineral density (BMD). In this study, lowintensity vibration platforms were developed to evaluate the effects of mechanical vibration on neuromuscular function and functional capacity in osteopenic postmenopausal women. This was a longitudinal case-control study conducted in 122 women divided into two groups matched for age, and ethnicity: 62 in the platform group (PG - 63.24 ± 9.84 years) and 60 in the control group (CG - 62.88 ± 7.87 years). Five times a week, during 20 minutes over 12 months, the volunteers in the PG stood still and barefoot on the platform which vibrated with a frequency of 60 Hz, intensity of 0.6g and amplitude < 1mm. The volunteers in the CG were followed up and instructed to maintain their usual physical activity. At the beginning and end of the study, isometric muscle strength was assessed by dynamometry: hip flexors (HF), back extensors (BE) and right handgrip (RH) stMechanical loading stimulation of bone with physical exercise has been described in the literature as an important non-pharmacological method to prevent and develop the musculoskeletal system. Mechanical stimulation with low intensity and low frequency vibration has been evaluated as a new, effective and safe way to improve muscle strength and bone mineral density (BMD). In this study, lowintensity vibration platforms were developed to evaluate the effects of mechanical vibration on neuromuscular function and functional capacity in osteopenic postmenopausal women. This was a longitudinal case-control study conducted in 122 women divided into two groups matched for age, and ethnicity: 62 in the platform group (PG - 63.24 ± 9.84 years) and 60 in the control group (CG - 62.88 ± 7.87 years). Five times a week, during 20 minutes over 12 months, the volunteers in the PG stood still and barefoot on the platform which vibrated with a frequency of 60 Hz, intensity of 0.6g and amplitude < 1mm. The volunteers in the CG were followed up and instructed to maintain their usual physical activity. At the beginning and end of the study, isometric muscle strength was assessed by dynamometry: hip flexors (HF), back extensors (BE) and right handgrip (RH) strength. Dynamic upper limb strength was assessed with elbow flexion (EF). Additional, tests included the functional reach test (RT), mobility (TUG), and static balance, assessed with unipedal stance test (UST). The results showed that after 12 months, the PG presented significant (p < 0.05) in (HF ± 36.7 %), (BE ±36.5% and RH ± 4.4%), and dynamic (EF ± 22.8%) muscle strength. The RT improved by (9.9%) and the (UST by 6.8%). In the CG there was a significant decrease of -3.9 % in RH isometric strength. There was an improvement on the TUG reflected by a reduction of -9.2 % in execution time. We conclude that low-intensity vibration was effective in improving muscle strength in the upper and lower limbs, balance, and mobility in postmenopausal woman.rength. Dynamic upper limb strength was assessed with elbow flexion (EF). Additional, tests included the functional reach test (RT), mobility (TUG), and static balance, assessed with unipedal stance test (UST). The results showed that after 12 months, the PG presented significant (p < 0.05) in (HF ± 36.7 %), (BE ±36.5% and RH ± 4.4%), and dynamic (EF ± 22.8%) muscle strength. The RT improved by (9.9%) and the (UST by 6.8%). In the CG there was a significant decrease of -3.9 % in RH isometric strength. There was an improvement on the TUG reflected by a reduction of -9.2 % in execution time. We conclude that low-intensity vibration was effective in improving muscle strength in the upper and lower limbs, balance, and mobility in postmenopausal woman.

A aplicação de sobrecargas mecânicas no osso através de exercícios físicos são estímulos já descritos na literatura como importantes ferramentas não medicamentosas para prevenção e incremento do sistema músculo esquelético. A estimulação mecânica por meio de vibrações de baixa intensidade e frequência tem sido estudada como uma maneira nova, segura e eficaz para melhora de força muscular e densidade mineral óssea (DMO). Neste estudo foram desenvolvidas plataformas vibratórias de baixa intensidade para avaliar os efeitos da vibração mecânica na função neuromuscular e capacidade funcional de mulheres osteopênicas pós menopausadas. O estudo longitudinal caso controle foi conduzido com 122 mulheres divididas em dois grupos: 62 no grupo plataforma (GP 63,24 ± 9,84 anos) e 60 no grupo Controle (GC 62,88 ± 7,87 anos) pareadas por idade, e etnia. As voluntárias do GP ficaram em pé descalças (sem realização de exercícios) na plataforma cuja frequência era de 60 Hz e uma intensidade vibratória de 0,6g e <1mm de amplitude, 5x por semana, 20 minutos, durante 12 meses. As voluntárias do GC foram acompanhadas e orientadas para não modificar suas atividades físicas habituais. No inicio e término do estudo, foram avaliados através da dinamometria, força muscular isométrica de: flexores de quadril (FQ), extensores da coluna (EC) e força de preensão manual direita (FPM). A força dinâmica de membros superiores foi avaliada pelo teste de flexão de cotovelo (FC). Foram realizados ainda a avaliação do alcance funcional pelo reach test (AF), mobilidade (TUG) e equilíbrio estático pelo teste unipodal (EE). Os resultados mostraram que após 12 meses no GP houve uma melhora significante (p<0,05) na força muscular isométrica (FQ ± 36,7%, EC ± 36,5%) e (FPM ± 4,4%), assim como dinâmica de (FC ± 22,8%). AF melhorou 9,9%, bem como o EE 6,8%. No CG observamos uma diminuição significativa da força isométrica de FPM esquerda de -3,9%. No TUG houve uma melhora demonstrada pelo menor tempo de execução após 12 meses (-9,2%), o que não mostrou significância no GP. Concluímos que a vibração de baixa intensidade foi eficaz em melhorar a força muscular de membros superiores e inferiores, bem como equilíbrio e mobilidade em mulheres na pós-menopausa.