Relationship of the skin and subcutaneous tissue thickness in the tensiomyography response: a novel ultrasound observational study

SUMMARY BACKGROUND: The aim of the study was to describe and correlate the skin, subcutaneous tissue, and superficial fascia thickness assessed by ultrasonography (US) with the lumbar erector spinae muscles contractile properties evaluated by tensiomyography (TMG). METHODS: A cross-sectional descriptive study with 50 healthy participants was performed. The point of maximum lordosis in the lumbar region of the right erector spinae was evaluated by US and TMG. First, the skin, subcutaneous tissue, and superficial fascia thicknesses (cm) were assessed by US. Second, the five contractile TMG parameters were analyzed from the right erector spinae muscles belly displacement-time curves: maximal radial displacement (Dm), contraction time (Tc), sustain time (Ts), delay time (Td), and half-relaxation time (Tr). Finally, correlation analyses using Pearson (r for parametric data) and Spearman (rs for non-parametric data) coefficients were performed. RESULTS: A strong negative correlation was shown between Dm and subcutaneous tissue thickness (rs=-0.668; P<.001). Furthermore, moderate negative correlations were observed between Dm and skin thickness (r=-0.329; P=0.020) as well as Tr and subcutaneous tissue thickness (rs=-0.369; P=0.008). The rest of the parameters did not show statistically significant correlations (P >.05). CONCLUSION: Therefore, the lumbar erector spinae contractile properties during TMG assessments, especially Dm and Tr, may be widely correlated by the skin and subcutaneous tissue thickness.

RESUMO CONTEXTO: O estudo foi elaborado para descrever e correlacionar a pele, o tecido subcutâneo e a espessura da fascia superficial avaliados pelo ultrassom (EUA) com as propriedades contráteis do músculo eretor da coluna lombar avaliadas por tensiomiografia (TMG). MÉTODOS: Foi realizado um estudo descritivo transversal com 50 participantes saudáveis. O ponto de lordose máxima na região lombar da coluna ereta direita foi avaliado pelos EUA e TMG. Primeiro, a pele, o tecido subcutâneo e as espessuras da fáscia superficial (cm) foram avaliadas pelos EUA. Em segundo lugar, os cinco parâmetros TMG contráteis foram analisados a partir das curvas de deslocamento-tempo da barriga do músculo eretor da espinha direita: deslocamento radial máximo (Dm), tempo de contração (Tc), tempo de sustentação (Ts), tempo de atraso (Td) e meio tempo de relaxamento (Tr). Finalmente, foram realizadas análises de correlação usando os coeficientes Pearson (r para dados paramétricos) e Spearman (rs para dados não paramétricos). RESULTADOS: Uma correlação forte negativa foi mostrada entre Dm e espessura subcutânea do tecido (rs = −0,668; P < 0,001). Além disso, foram observadas correlações moderadas negativas entre Dm e espessura da pele (r = −0,329; P = 0,020), bem como a espessura subcutânea do tecido (rs = −0,369; P = 0,008). O restante dos parâmetros não mostrou correlações estatisticamente significativas (P > 0,05). CONCLUSÃO: Portanto, as propriedades contráteis do eretor da espinha lombar durante as avaliações TMG, especialmente Dm e Tr, podem ser amplamente correlacionadas com a pele e a espessura subcutânea do tecido.

[Comparison of activation pattern of selected trunk muscles during over ground and treadmill walking]

Given the biomechanical differences between over ground and treadmill walking, it is expected that the contraction of muscles should be also different, so exercise training in these scenarios may have various effects on trunk muscles. The aim of this study was to compare amplitude and duration of activation of trunk muscles during over ground and treadmill walking to prescribe a suitable exercise mode considering the special circumstances of each person. Nineteen healthy 20-40 years old male with sedentary life style were selected via simple sampling. Surface electromyography of rectus abdominis, external oblique, longissimus and multifidus muscles were recorded. In each gait cycle, there was not statistically significant differences on duration of trunk muscles activity between treadmill and over ground walking. The mean amplitude of these muscles was greater on treadmill in comparison with over ground and this difference was statistically significant for rectus abdominis [P=0.005], longissimus [P=0.018] and multifidus [P=0.044] muscles. Stabilizing role of trunk muscles during walking causes them to be active throughout the entire gait cycle. The increased muscle amplitude on treadmill might show that more motor units may be recruited during the contraction, which is helpful in prescribing the appropriate type of exercise especially to patients who have trunk muscles weakness