Localization of the centre of the highest region of the triceps brachii muscle spindle abundance and its significance in muscle spasticity block / Localización del centro de la región más alta del huso del músculo tríceps braquial y su importancia en el bloqueo de la espasticidad muscular

SUMMARY: This study aimed to accurately localize the location and depth of the centre of the highest region of muscle spindle abundance (CHRMSA) of the triceps brachii muscle. Twenty-four adult cadavers were placed in the prone position. The curve connecting the acromion and lateral epicondyle of the humerus close to the skin was designed as the longitudinal reference line (L), and the curve connecting the lateral and the medial epicondyle of the humerus was designed as the horizontal reference line (H). Sihler's staining was used to visualize the dense intramuscular nerve region of the triceps brachii muscle. The abundance of muscle spindle was calculated after hematoxylin and eosin stain. CHRMSA was labelled by barium sulphate, and spiral computed tomography scanning and three- dimensional reconstruction were performed. Using the Syngo system, the projection points of CHRMSA on the posterior and anterior arm surface (P and P' points), the position of P points projected to the L and H lines (PL and PH points), and the depth of CHRMSA were determined. The PL of the CHRMSA of the long, medial, and lateral heads of the triceps brachii muscle were located at 34.83 %, 75.63 %, and 63.93 % of the L line, respectively, and the PH was located at 63.46 %, 69.62 %, and 56.07 % of the H line, respectively. In addition, the depth was located at 34.73 %, 35.48 %, and 35.85 % of the PP' line, respectively. These percentage values are all the means. These body surface locations and depths are suggested to be the optimal blocking targets for botulinum toxin A in the treatment of triceps brachii muscle spasticity.

RESUMEN: Este estudio tuvo como objetivo localizar con precisión la ubicación y la profundidad del centro de la región más alta del huso muscular (CHRMSA) del músculo tríceps braquial. Se colocaron veinticuatro cadáveres adultos en posición prona y se designó la curva que conecta el acromion y el epicóndilo lateral del húmero cerca de la piel como la línea de referencia longitudinal (L), y la curva que conecta los epicóndilos lateral y medial del húmero fue designada como la línea de referencia horizontal (H). Se usó la tinción de Sihler para visualizar la región nerviosa intramuscular densa del músculo tríceps braquial. La abundancia de huso muscular se calculó después de la tinción con hematoxilina y eosina. CHRMSA se marcó con sulfato de bario y se realizó una tomografía computarizada espiral y una reconstrucción tridimensional. Usando el sistema Syngo, fueron determinados los puntos de proyección de CHRMSA en la superficie posterior y anterior del brazo (puntos P y P'), la posición de los puntos P pro- yectados en las líneas L y H (puntos PL y PH) y la profundidad de CHRMSA. Los PL de la CHRMSA de las cabezas larga, medial y lateral del músculo tríceps braquial se ubicaron en el 34,83 %, 75,63 % y 63,93 % de la línea L, respectivamente, y el PH se ubicó en el 63,46 %, 69,62 %, y 56,07 % de la línea H, respectivamente. La profundidad se ubicó en el 34,73 %, 35,48 % y 35,85 % de la línea PP', respectivamente. Estos valores porcentuales son todas las medias. Se sugiere que estas ubicaciones y profundidades de la superficie corporal son los objetivos de bloqueo óptimos para la toxina botulínica A en el tratamiento de la espasticidad del músculo tríceps braquial.

Different types of mechanical vibration application on EMG response and strength performance

Abstract Aim: The present study aimed to compare the strength performance and the neuromuscular activity during one maximum repetition test (1RM), and the maximum voluntary isometric contractions (MVIC) performed with whole-body vibration (WBV), local vibration (LV), and no vibration (NV). Methods: The sample consisted of 15 males, experienced in strength training for at least 6 months, which performed all strength tests in the barbell curl exercise across randomized trials on the following conditions: NV, WBV, and LV. During all tests, the normalized root means square values of the electromyographic signals (EMGRMS) of the biceps brachii and brachioradialis were recorded and compared between the conditions. The one-way ANOVAs with repeated measures were used to compare the results of 1RM and MVIC tests and the normalized EMGRMS between the conditions. When necessary, a post hoc Scott-Knott test was used to identify the differences reported in the ANOVAs. The significance level adopted was α < 0.05. Results: The EMGRMS response of the biceps brachii and brachioradialis muscles during the 1RM and MVIC tests presented significantly higher values at LV compared to WBV, and NV (p < 0.001). The 1RM tests, and the MVIC results were similar between conditions (p = 0.9803; p = 0.061, respectively). Conclusion: These results indicate that the application of MV was not sufficient to increase strength performance.