Effects of therapeutic ultrasound on the mechanical properties of skeletal muscles after contusion

CONTEXTUALIZAÇÃO: O ultra-som terapêutico (UST) é um recurso comumente aplicado na aceleração do reparo tecidual de lesões musculares. A absorção das ondas ultra-sônicas é determinada pela freqüência e pela intensidade, sendo que, em uma mesma intensidade, a profundidade atingida por 1MHz é maior quando comparada a 3MHz. OBJETIVO: Analisar o comportamento das propriedades mecânicas de músculos submetidos à lesão aguda por impacto e tratados com UST, utilizando as freqüências de 1 e 3MHz. MATERIAIS E MÉTODOS: Foram utilizadas 40 ratas Wistar (200,1±17,8g), divididas em quatro grupos: (1) controle; (2) lesão muscular sem tratamento; (3) lesão muscular tratada com UST de freqüência 1MHz (0,5W/cm²) e (4) lesão muscular tratada com UST de freqüência 3MHz (0,5W/cm²). A lesão foi provocada no músculo gastrocnêmio por mecanismo de impacto. O tratamento foi de cinco minutos diários durante seis dias consecutivos. Os músculos foram submetidos a ensaios mecânicos de tração em uma máquina universal de ensaios. RESULTADOS: As médias e desvios-padrão das propriedades mecânicas dos grupos lesionados e tratados com UST foram significativamente maiores quando comparadas ao grupo lesionado sem tratamento (p<0,05). Em destaque, a propriedade de rigidez que, com a aplicação do UST, teve acréscimo de aproximadamente 38%. CONCLUSÕES: A intervenção, por meio do UST, promoveu aumento das propriedades mecânicas nos músculos lesionados aproximando-as do grupo controle. Entretanto, não foi observada diferença significativa entre as propriedades mecânicas dos grupos tratados com ultra-som de freqüências 1MHz e 3MHz.BACKGROUND: Therapeutic ultrasound is a resource commonly applied to speed up tissue repair in muscle injuries. The absorption of the ultrasound waves is determined by their frequency and intensity. For a given intensity, the depth reached by 1MHz is greater than the depth reached by 3MHz. OBJECTIVE: To analyze the mechanical properties of muscles subjected to acute impact injury treated with therapeutic ultrasound at the frequencies of 1 and 3MHz. METHODS: Forty female Wistar rats (200.1±17.8g) were used, divided into four groups: (1) control; (2) muscle injury without treatment; (3) muscle injury treated with therapeutic ultrasound at the frequency of 1MHz (0.5W/cm²); and (4) muscle injury treated with therapeutic ultrasound at the frequency of 3MHz (0.5W/cm²). The injury was produced in the gastrocnemius muscle by means of an impact mechanism. The treatment consisted of a single five-minute session per day, for six consecutive days. The muscles were subjected to mechanical traction tests in a universal test machine. RESULTS: Means and standard deviations for the mechanical properties of the injured groups that received therapeutic ultrasound were significantly greater than those of the injured group without treatment (p<0.05). The property of stiffness should be highlighted: the application of therapeutic ultrasound increased muscle stiffness by approximately 38%. CONCLUSIONS: Therapeutic ultrasound increased the mechanical properties of the injured muscles, and brought them to a level close to the control group. However, no significant difference in mechanical properties was observed between the groups treated with ultrasound at the frequencies of 1MHz and 3MHz

Propriedades mecânicas do músculo de ratos adultos e idosos, exercitado pós-imobilização

OBJECTIVES: To describe the effects of immobilization, free remobilization and remobilization by physical exercise about mechanical properties of skeletal muscle of rats of two age groups. METHODS: 56 Wistar rats divided into two groups according to age, an adult group (five months) and an older group (15 months). These groups were subdivided in: control, immobilized, free remobilized and remobilized by physical exercise. The pelvic limb of rats was immobilized for seven days. The exercise protocol consisted of five swimming sessions, once per day and 25 minutes per session. The gastrocnemius muscle was subjected to tensile tests, and evaluated the properties: load at the maximum limit, stretching at the maximum limit and stiffness. RESULTS: The immobilization reduced the values of load at the maximum limit and the remobilization protocols were not sufficient to restore control levels in adult group and older rats. The stretching at the maximum limit differs only in the older group. CONCLUSIONS: The immobilization reduces the muscle's ability to bear loads and exercise protocol tends to restore the default at control values in adult and older rats. The age factor only interfered in the stretching at the maximum limit, inducing a reduction of this property in the post-immobilization. Level of Evidence II, Investigating the Results of Treatment

Supplement with Cystoseira canariensis promotes an increase of resistance to the maximum load in the grastrocnemius muscle of female rats

Was evaluated the maximum load supported by the grastrocnemius muscle of female rats after the ministering of Cystoseira canariensis, either associated or not to swimming. Twenty-eight young Wistar female rats were used, divided into 4 groups: control (C, n=7); supplement (S, n=7); supplement and swimming (SSw, n=7); swimming (Sw, n=7). Each one pertaining to the groups S and SSw received 20 mg of myostatin inhibitor per day. The swimming consisted in an aerobe protocol, three times in a week, during eight weeks. The right grastrocnemius muscle of each animal was removed and a tension test was performed in an Emic testing machine. The results (Mean&#177;SEM) were evaluated through ANOVA and Tukey test (p<0.05). A significant difference for maximum load (in N) was verified among the groups C (35.41&#177;1.06) and S (39.98&#177;1.15); Sw (27.94&#177;2.19) and S (39.98&#177;1.15); Sw (27.94&#177;2.19) and SSw (37.78&#177;1.28). In relation to the stretching at the maximum limit (in x10-3m) at the maximum load, the group SSw obtained a value (20.68&#177;1.19) significantly greater than the groups C (17.15&#177;1.11), S and Sw (16.11&#177;1.60). There was a significant difference for body weight gain among the groups treated with supplement and supplement associated to the swimming, with smaller values for this last. The myostatin inhibitor either, associated or not to the swimming, promotes an increase of resistance to the maximum load in the tension test in grastrocnemius muscle of young female rats

Association between sarcopenia and quality of life in quilombola elderly in Brazil

Luiz Sin&eacute;sio Silva Neto,1&ndash;3 Marg&ocirc; GO Karnikowski,2 Neila B Os&oacute;rio,3 Leonardo C Pereira,2 Marcilio B Mendes,1 Dayani Galato,2 Liana B Gomide Matheus,4 Jo&atilde;o Paulo C Matheus2,4 1School of Medicine, Federal University of Tocantins, Palmas, Tocantins, 2Graduate Program in Health Sciences and Technology, Ceil&acirc;ndia College, University of Brasilia, Federal District, 3Graduate Program in Education, Federal University of Tocantins, Palmas, Tocantins, 4School of Physiotherapy, Ceil&acirc;ndia College, University of Bras&iacute;lia, Federal District, Brazil Introduction: Currently, there is no single consensual definition of sarcopenia in the literature. This creates a challenge for the evaluation of its prevalence and its direct or indirect impact on the quality of life of elderly populations of different races and ethnicities. Furthermore, no studies as yet have analyzed these variables in populations of elderly subjects of the &quot;quilombola&quot; ethnic group. Objective: We aimed to verify the association between sarcopenia and quality of life in quilombola elderly using the Baumgartner and the European Working Group on Sarcopenia in Older People (EWGSOP) criteria. Methods: This was a cross-sectional study of 70 male and female participants (mean age: 65.58&plusmn;6.67 years). Quality of life was evaluated using the multidimensional 36-item Short-Form Health Survey (SF-36) of the Medical Outcomes Study. Sarcopenia was diagnosed according to the Baumgartner cutoff for appendicular skeletal muscle mass and the criteria recommended by the EWGSOP. Muscle mass and fat mass percentages were analyzed by dual-energy X-ray absorptiometry, while handgrip strength (HGS) was evaluated using a hand-held dynamometer. Physical performance was assessed through a gait speed test. Results: The prevalence of sarcopenia was 15% according to the Baumgartner cutoff and 10% according to EWGSOP criteria. Quilombola elderly classified as physically active or very active were at least six times less likely to develop sarcopenia than those classified as irregularly active or sedentary. HGS was negatively associated with a diagnosis of sarcopenia according to both sets of criteria. Subjects with sarcopenia reported lower scores than those without the condition on the physical role functioning and bodily pain domains of the SF-36. Conclusion: In this sample of quilombola elderly, quality of life was negatively associated with sarcopenia, regardless of the classification criteria used. Additionally, the results showed that diagnostic criteria for sarcopenia should include reductions in lean mass in addition to measures of functioning and physical performance because some subjects showed the former symptom without any alteration of the latter two variables. The cutoff value suggested by Baumgartner criteria were less accurate than that specified by the EWGSOP criteria because they do not consider functioning and physical performance. However, Baumgartner criteria were more sensitive in detecting sarcopenia because reductions in lean mass predict alterations in strength and walking speed. Keywords: sarcopenia, quality of life, elderly, quilombola, vulnerable group