Balance and muscle power of children with Charcot-Marie-Tooth / Equilíbrio e potência muscular em crianças com doença de Charcot-Marie-Tooth

BACKGROUND: In certain diseases, functional constraints establish a greater relationship with muscle power than muscle strength. However, in hereditary peripheral polyneuropathies, no such relationship was found in the literature. OBJECTIVE: In children with Charcot-Marie-Tooth (CMT), to identify the impact of muscle strength and range of movement on the static/dynamic balance and standing long jump based on quantitative and functional variables. METHOD: The study analyzed 19 participants aged between 6 and 16 years, of both genders and with clinical diagnoses of CMT of different subtypes. Anthropometric data, muscle strength of the lower limbs (hand-held dynamometer), ankle and knee range of movement, balance (Pediatric Balance Scale) and standing long jump distance were obtained by standardized procedures. For the statistical analysis, Pearson and Spearman correlation coefficients were used. RESULTS: There was a strong positive correlation between balance and the muscle strength of the right plantar flexors (r=0.61) and dorsiflexors (r=0.59) and a moderate correlation between balance and the muscle strength of inversion (r=0.41) and eversion of the right foot (r=0.44). For the long jump and range of movement, there was a weak positive correlation with right and left plantar flexion (r=0.20 and r=0.12, respectively) and left popliteal angle (r=0.25), and a poor negative correlation with left dorsiflexion (r=-0.15). CONCLUSIONS: The data on the patients analyzed suggests that the maintenance of distal muscle strength favors performance during balance tasks, while limitations in the range of movement of the legs seem not to be enough to influence the performance of the horizontal long jump. .

CONTEXTUALIZAÇÃO: Em algumas doenças, limitações funcionais têm maior relação com a potência do que com a força muscular, porém, nas polineuropatias periféricas hereditárias, tal relação não foi relatada na literatura. OBJETIVO: Identificar, a partir da análise de variáveis quantitativas e funcionais, o impacto da força dos músculos dos membros inferiores e das amplitudes de movimento (ADM) sobre o equilíbrio estático/dinâmico e o salto horizontal de crianças com doença de Charcot-Marie-Tooth (CMT). MÉTODO: Foram incluídos 19 participantes de seis a 16 anos, de ambos os sexos, com diagnóstico clínico de CMT de subtipos variados. Foram obtidos, de forma padronizada, dados antropométricos, força muscular dos membros inferiores (Hand-Held Dynamometer), ADM de tornozelos e joelhos, equilíbrio (Escala de Equilíbrio Pediátrica) e distância de salto horizontal (Long Jump). Para a análise estatística, utilizaram-se os Coeficientes de Correlação de Pearson e Spearman. RESULTADOS: Houve forte correlação positiva entre equilíbrio e força muscular de flexores plantares direito (r=0,61) e dorsiflexores (r=0,59) e correlação moderada com inversores dos pés (r=0,41) e eversores do pé direito (r=0,44). Considerando o Long Jump e as ADM, houve fraca correlação positiva para ADM de flexão plantar direita (r=0,20), esquerda (r=0,12) e ângulo poplíteo esquerdo (r=0,25) e fraca correlação negativa para dorsiflexão esquerda (r=-0,15). CONCLUSÕES: Os dados dos pacientes analisados sugerem que a manutenção de força muscular distal favorece o desempenho em tarefas de equilíbrio. E as restrições nas ADM passivas de membros inferiores parecem ...

Longitudinal assessment of grip strength using bulb dynamometer in Duchenne Muscular Dystrophy

BACKGROUND: Grip strength is used to infer functional status in several pathological conditions, and the hand dynamometer has been used to estimate performance in other areas. However, this relationship is controversial in neuromuscular diseases and studies with the bulb dynamometer comparing healthy children and children with Duchenne Muscular Dystrophy (DMD) are limited. OBJECTIVE: The evolution of grip strength and the magnitude of weakness were examined in boys with DMD compared to healthy boys. The functional data of the DMD boys were correlated with grip strength. METHOD: Grip strength was recorded in 18 ambulant boys with DMD (Duchenne Group, DG) aged 4 to 13 years (mean 7.4±2.1) and 150 healthy volunteers (Control Group, CG) age-matched using a bulb dynamometer (North Coast- NC70154). The follow-up of the DG was 6 to 33 months (3-12 sessions), and functional performance was verified using the Vignos scale. RESULTS: There was no difference between grip strength obtained by the dominant and non-dominant side for both groups. Grip strength increased in the CG with chronological age while the DG remained stable or decreased. The comparison between groups showed significant difference in grip strength, with CG values higher than DG values (confidence interval of 95%). In summary, there was an increment in the differences between the groups with increasing age. Participants with 24 months or more of follow-up showed a progression of weakness as well as maintained Vignos scores. CONCLUSIONS: The amplitude of weakness increased with age in the DG. The bulb dynamometer detected the progression of muscular weakness. Functional performance remained virtually unchanged in spite of the increase in weakness. .

Postural alignment in children with Duchenne muscular dystrophy and its relationship with balance

Background: In Duchenne muscular dystrophy, functional deficits seem to arise from body misalignment, deconditioning, and obesity secondary to weakness and immobility. The question remains about the effects of postural deviations on the functional balance of these children. Objectives: To identify and quantify postural deviations in children with DMD in comparison to non-affected children (eutrophic and overweight/obese), exploring relationships between posture and function. Method: This case-control study evaluated 29 participants aged 6 to 11 years: 10 DMD (DG), 10 eutrophic (EG), and 9 overweight/obese (OG). Digital photogrammetry and SAPo program were used to measure postural alignment and the Pediatric Balance Scale (PBS) was used to measure balance. The Kruskall-Wallis and Dunn post-hoc tests were used for inter-group comparison of posture and balance. Spearman's coefficient tested the correlation between postural and balance variables. Results: The horizontal pelvic alignment data indicated that the anteversion of the DG was similar to that of the OG and twice that of the EG (p<0.05). Compared to the EG, the DG and OG showed an increased forward position of the center of mass (p<0.05). There was a moderate and weak correlation between the PBS score and horizontal pelvic alignment (0.58 and 0.47-left/right). The PBS showed a weak correlation with asymmetries in the sagittal plane (-0.39). The PBS scores for the OG and EG suggest that obesity did not have a deleterious effect on balance. Conclusions: The balance deficit in children with DMD was accompanied by an increased forward position of the center of mass and significant pelvic anteversion that constitutes a compensatory strategy to guarantee similar performance to the children not affected by the disease. .

Efeitos morfológicos do retorno da sobrecarga após imobilização em alongamento de músculo esquelético de ratas / Morphological effects of resumption of loading after immobilization of skeletal muscles in lengthened position in female rats

CONTEXTUALIZAÇÃO: Na reabilitação, a imobilização em alongamento do músculo esquelético é realizada como contramedida para reverter efeitos de encurtamento muscular severo e em eventos pós-cirúrgicos. Acredita-se que o retorno às atividades funcionais normais estimule mecanotransdutores capazes de reorganizar a citoarquitetura normal muscular, porém a descrição das alterações histopatológicas relacionadas a esses procedimentos são escassas na literatura. OBJETIVOS: Avaliar e quantificar anomalias histológicas induzidas pela imobilização em alongamento do músculo EDL (Extensor Digitorum Longus) e confrontá-las com a livre movimentação do animal após esse procedimento. MÉTODOS: Foram utilizadas 18 ratas Wistar, distribuídas nos grupos: controle (GC); imobilizadas em flexão plantar (EDL em posição alongada) por 14 dias (GI); imobilizadas por 14 dias e liberadas por dez dias (GIL). Fragmentos do EDL foram congelados, seccionados e processados com reações imuno-histoquímica para colágenos I e III e histoquímica para Adenosina Trifosfatase Miofibrilar e Hematoxilina-Eosina. RESULTADOS: Os animais do GI apresentaram discreto aumento da expressão de colágeno I e de fibras em processo degenerativo/necrótico, redução da proporção de fibras tipo (FT) 2A e do diâmetro menor de todos os tipos de fibras, quando comparados com os animais do GC. Para o GIL, observou-se retorno da quantidade de colágeno I às condições controle, além de redução na proporção de FT2D, aumento do número de núcleos centralizados e do diâmetro menor das fibras quando comparadas com o GI, porém a expressão de FT2B e FT2D não atingiu os valores de referência. CONCLUSÕES: Os dados apresentados mostram que a retomada da função durante dez dias foi parcialmente eficiente na recuperação das características do músculo EDL após o período de imobilização e que, se extrapolados os dados à clínica fisioterapêutica, a adoção de procedimentos orientados às disfunções primárias do músculo pode favorecer a resposta morfofuncional do segmento e o seu íntegro restabelecimento.

BACKGROUND: In rehabilitation, immobilization of skeletal muscles in the elongated position is performed as a countermeasure in order to reverse the effects of severe muscle shortening and postoperative events. The return to normal functional activities is believed to stimulate mechanotransducers capable of reorganizing the normal muscle cytoarchitecture, but few data describing the histopathological changes relating to these procedures are available in the literature. OBJECTIVES: To assess and quantify histological abnormalities induced by immobilization of the extensor digitorum longus (EDL) muscle in elongation and to compare them with free movement of the animal after this procedure. METHODS: Eighteen female Wistar rats were used, divided into the following groups: Control; Immobilized in plantar flexion (EDL in an elongated position) for 14 days (GI); Immobilized for 14 days and released for 10 days (GIL). EDL fragments were frozen, sectioned and processed through immunohistochemical reactions for collagens I and III and histochemical methods for myofibrillar adenosine triphosphatase using hematoxylin-eosin. RESULTS: GI animals presented slight increases in collagen I and fiber expression in a degenerative/necrotic process, and reductions in the proportion of FT2A fibers and in the diameters of all fiber types, compared with the controls. In GIL, the quantity of collagen I returned to control conditions; the proportion of FT2D decreased; the number of centralized nuclei increased; and the fiber diameter was smaller than in GI. However, FT2B and FT2D expression did not reach the reference values. CONCLUSIONS: The data presented show that the recovery of function over a 10-day period was partially efficient with regard to recuperation of the characteristics of the EDL muscle after the period of immobilization. If the data are extrapolated to physiotherapeutic clinical practice, use of procedures directed towards primary dysfunctions of the muscle may favor a morphofunctional response in the segment and its full recovery.