Assessment of Muscle Contractile Properties at Acute Moderate Altitude Through Tensiomyography.

Under hypoxia, alterations in muscle contractile properties and faster fatigue development have been reported. This study investigated the efficacy of tensiomyography (TMG) in assessing muscle contractile function at acute moderate altitude. Biceps femoris (BF) and vastus lateralis (VL) muscles of 18 athletes (age 20.1 ± 6.1 years; body mass 65.4 ± 13.9 kg; height 174.6 ± 9.5 cm) were assessed at sea level and moderate altitude using electrically evoked contractions on two consecutive days. Maximum radial displacement (Dm), time of contraction (Tc), reaction time (Td), sustained contraction time (Ts), and relaxation time (Tr) were recorded at 40, 60, 80, and 100 mA. At altitude, VL showed lower Dm values at 40 mA (p = 0.008; ES = -0.237). Biceps femoris showed Dm decrements in all electrical stimulations (p < 0.001, ES > 0.61). In VL, Tc was longer at altitude at 40 (p = 0.031, ES = 0.56), and 100 mA (p = 0.03, ES = 0.51). Regarding Td, VL showed significant increases in all electrical intensities under hypoxia (p ≤ 0.03, ES ≥ 0.33). TMG appears effective at detecting slight changes in the muscle contractile properties at moderate altitude. Further research involving TMG along with other muscle function assessment methods is needed to provide additional insight into peripheral neuromuscular alterations at moderate altitude.

Mechanical response of knee muscles in high level bodyboarders during performance / Respostas mecânicas da musculatura do joelho de bodyboarders de alto nível durante o desempenho / Respuesta mecánica de la musculatura de la rodilla en bodyboarders de alto nivel durante el desempeño

INTRODUCTION: bodyboarding is a kind of surfing that has been growing very rapidly over the last decade and has now developed into one of the fastest growing water sports in the world. OBJECTIVES: evaluate the effects of fatigue on rectus femoris RF, vastus lateralis VL and vastus medialis VM and biceps femoris BF and semitendinosus ST during a high-level bodyboard competition using tensiomyography TMG. METHODS: subjects were 11 highly experienced years of practice: 15, SD=4.65 male bodyboarders age: 28.17, SD=2.89, body weight: 74.83, SD=6.13kg; height: 179.25, SD=3.93cm; BMI: 23.29, SD=1.81 participating in the final of the 2010 Spanish championship. RESULTS: the fatigue is especially evident due to a decrease in the values of relaxation time Tr and sustain time Ts caused by the specific characteristics of waves, how the waves evolve and the type of manoeuvre executed in competition due to the wave characteristics. The maximum radial displacement Dm value increased slightly in all muscles analysed and normalised response speed Vrn was stable, with a tendency to improve as athletes adapted to the type of physical effort and the environmental conditions of the competition. CONCLUSIONS: the study shows that the fatigue in the extensor and flexor muscles of the knee occurs in response to the demands of competition. .

INTRODUÇÃO: bodyboarding é uma modalidade do surfe que vem crescendo rapidamente nas últimas décadas e atualmente é um dos esportes aquáticos que mais cresce no mundo. OBJETIVO: avaliar o efeito da fadiga nos músculos reto femoral RF, vasto lateral VL, vasto medial VM, bíceps femoral BF e semitendíneo ST durante competição de alto nível através da tensiomiografia TMG. MÉTODOS: a amostra foi composta por 11 bodyboarders de alto nível anos de prática: 15, DP = 4,65, idade: 28,17, DP = 2,89 anos, peso: 74,83, DP = 6,13 kg; estatura: 179,25, DP = 3,93 cm; IMC: 23,29, DP = 1,81, participantes da final do Campeonato Espanhol de 2010. RESULTADOS: a fadiga é evidente devido a uma diminuição dos valores de tempo de relaxamento Tr e tempo de sustentação Ts, que pode ser causada pelas características das ondas, de como elas se comportam e ao tipo de manobras realizadas em competição. Os valores de deslocamento radial máximo Dm aumentaram em todos os músculos analisados e a velocidade de resposta normalizada foi estável, com uma leve tendência à melhora conforme os atletas se adaptam ao tipo de esforço físico e às condições ambientais da competição. CONCLUSÃO: observou-se fadiga da musculatura flexora e extensora do joelho em repostas às demandas da competição. .

INTRODUCCIÓN: el bodyboard es una modalidad del surf que viene creciendo rápidamente en las últimas décadas y actualmente es uno de los deportes acuáticos que más crece en el mundo. OBJETIVOS: evaluar los efectos de la fatiga en los músculos: recto femoral RF, vasto lateral VL, vasto medial VM, bíceps femoral BF y semitendinoso ST durante una competición de alto nivel mediante la tensiomiografia TMG. MÉTODOS: la muestra estaba compuesta por 11 bodyboarders de alto nivel años de práctica: 15, DE = 4,65, edad: 28,17, DE = 2,89, peso: 74.83, DE = 6,13 kg; altura: 179,25, DE = 3,93 cm; IMC: 23,29, DE = 1,81, participantes en la final del Campeonato de España de 2010. RESULTADOS: la fatiga es evidente debido a una disminución de los valores del tiempo de relajación Tr y tiempo de sustentación Ts, que puede ser causada por las características de las olas, de como éstas se comportan y al tipo de maniobras realizadas durante la competición. Los valores de desplazamiento máximo radial Dm aumentaron en todos los músculos analizados y la velocidad de respuesta normalizada Vrn se muestra estable, con tendencia a mejorar, debido a la adaptación de los deportistas al tipo de esfuerzo y a las condiciones ambientales en que se desarrolla la competición. CONCLUSIÓN: el estudio muestra que la fatiga en los músculos extensores y flexores de la rodilla se produce en respuesta a las exigencias propias de la competición. .

Tensiomiografia utilizada para a avaliação de jogadores de vôlei de praia de alto nível / The tensiomyography used for evaluating high level beach volleyball players

OBJETIVO: Esta investigação tem por objetivo coletar dados sobre rigidez muscular, as propriedades mecânicas e contráteis dos músculos utilizando a TMG em jogadores de vôlei de praia de alto nível, assim como demonstrar a utilidade deste método para a avaliação dos músculos responsáveis pela flexão e extensão do joelho. MÉTODOS: A investigação foi conduzida com um grupo de 24 jogadores de vôlei de praia os quais participaram do Torneio Europeu Nestea - Master Espanhol realizado nas Ilhas Grâ-Canárias em maio de 2009. O método de estudo utilizado foi comparação de casos individuais de vários atletas com a finalidade de verificar a utilidade deste método em esportes. Os músculos analisados foram: vasto lateral (VL), vasto medial (ML), reto femoral (RF) e bíceps femoral (BF). RESULTADOS: As informações coletadas nos certificam sobre o alto grau de utilidade deste método para avaliação da rigidez muscular e equilíbrio entre estruturas musculares de atletas. Contudo, a validade e reconstrução dos resultados estão condicionadas a um severo protocolo de avaliação. Além disso, os seguintes critérios devem ser considerados: individualidade (o perfil do atleta) e especificações (características do esporte). CONCLUSÕES: A aplicação da TMG em jogadores de alto nível revela a existência de importantes diferenças dependendo de suas funções em jogo (defesa, bloqueio ou alternância entre ambas as posições), as ações técnicas, a posição em quadra (direita-esquerda) e o histórico de lesões médicas.

OBJECTIVE: The aim of this investigation is to obtain information about muscle stiffness, the mechanic and contractile properties of the muscles using the TMG with high level beach volleyball players as well as to demonstrate the usefulness of this method to evaluate the muscles in charge of the knee flexion and extension. METHODS: The investigation was carried out with a group of 24 beach volleyball players who took part in the Nestea European Championship Tour - Spanish Master held in the Gran Canaria, May 2009. The method of study used was a comparison of the individual cases of various athletes to ascertain the usefulness of this method in sports. The muscles which were analyzed are: vastus lateralis (VL), vastus medialis (ML), rectus femoris (RF) and biceps femoris (BF). RESULTS: Thus, with the information collected we can state the high level of usefulness of this method for the evaluation of muscle stiffness and balance between muscle structures of athletes. However, the validity and reconstruction of the results are conditioned to a strict protocol of evaluation. Moreover, the following criteria should be considered: individuality (the athlete's profile) and specifications (sport characteristics). CONCLUSIONS: The application of the TMG to high level players reveals the existence of important differences depending on their different roles in the game (defence, blocker or alternating both roles), the technical actions, the position on court (right-left) and the medical history of injuries.

Effect of high-load and high-volume resistance exercise on the tensiomyographic twitch response of biceps brachii.

The purpose of the present study was to assess the ability of TMG in detecting mechanical fatigue induced by two different resistance exercises on biceps brachii: high-volume (HV), and high-load (HL). Sixteen healthy subjects (age 25.1±2.6years; body mass 79.9±8.9kg; height 179±7.4cm) performed arm-curl in two different protocols (HV: 8×15×10kg, HL: 5×3×30kg). Tensiomyography was used to assess muscle response to both exercise protocols. The contractile capacity of biceps brachii significantly varied by means of the effects of potentiation and fatigue mechanisms that take place at different exercise phases. The most significant changes correspond to values of maximum radial displacement of muscle belly (D(m)), sustained contraction time (T(s)), relaxation time (T(r)), and contraction velocity (V(c)). The behavior of these parameters is, in general, similar in both exercise protocols, but they show subtle differences among them. During the first set, in both protocols, values for V(c) increase, along with a decrease in T(r), T(s), and D(m) values. Fatigue onset was evident from changes in such parameters, with HL being the first in showing these mechanisms. Tensiomyography has been shown to be highly sensitive in detecting fatigue-induced changes.

Effect of cold-water immersion on skeletal muscle contractile properties in soccer players.

OBJECTIVE: This study was designed to analyze changes in muscle response after cold-water immersion. DESIGN: The vastus lateralis of the dominant leg was analyzed in 12 professional soccer players from the Spanish 2nd Division B using tensiomyography, before and after four cold-water immersions at 4°C lasting 4 mins each. Core temperature, skin temperature, and heart rate were monitored. RESULTS: A significant interaction (P ≤ 0.05) was found in muscle deformation between control conditions (5.12 ± 2.27 mm) and (1) immersion 3 (3.64 ± 2.27 mm) and (2) immersion 4 (3.38 ± 1.34 mm). A steady decrease was also observed in response velocity (immersion 1, -7.3%; immersion 2, -25.9%; immersion 3, -30.0%; immersion 4, -36.6%) and contraction velocity (immersion 1, -11.5%; immersion 2, -22.1%; immersion 3, -35.0%; immersion 4, -41.9%), with statistically significant differences (P ≤ 0.05) in relation to the reference values commencing with the third immersion. No significant differences were found between control conditions in subsequent exposures to cold water for the values of response time and contraction time. Sustained time and reaction time showed an increase during repeated exposures and with longer exposure time, although the increase was not statistically significant. CONCLUSIONS: This study shows that repeated cold-water immersions (4 × 4 mins at 4°C) cause considerable alterations to muscle behavior. These alterations significantly affect the state of muscles and their response capacity, particularly in relation to muscle stiffness and muscle contraction velocity.

Assessment of muscle fatigue after an ultra-endurance triathlon using tensiomyography (TMG).

In this study, we used tensiomyography (TMG) to assess muscle status immediately after an ultra-endurance triathlon. Maximal radial displacement or deformation of the muscle belly, contraction time, delay time, sustain time, and relaxation time were measured for both legs, and dependent t-tests were used to compare means between the beginning and end of the race. The 19 men assessed (age 37.9 ± 7.1 years; height 177.5 ± 4.6 cm; weight: 73.6 ± 6.5 kg) participated in the 2009 edition of the Lanzarote Ironman. Deterioration in the neural response was observed for contraction time (P = 0.008) and relaxation time (P = 0.011), with a moderate decrease in the response time (sustain time) and a loss in muscle stiffness (deformation of the muscle belly). The effect of muscle fatigue on the rectus femoris and biceps femoris was different. Barely any changes in contraction time, relaxation time, sustain time, and deformation of the muscle belly were observed, while only the contraction response time decreased to a significant extent (reduction in delay time; P = 0.003). The considerable loss in contractile capacity induced by a long-distance race was reflected in changes in the neuromuscular response and fluctuations in the contractile capacity of the muscle. These modifications, derived from a prolonged, exhausting effort, can be assessed in a simple, non-aggressive, non-invasive way using tensiomyography.