Samuel Sarmiento

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

Abstract 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.

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.

Relation between In-Game Role and Service Characteristics in Elite Women's Volleyball

Quiroga, ME, García-Manso, JM, Rodríguez-ruiz, D, Sarmiento, S, de Saa, Y, and Moreno, MP. Relation between in-game role and service characteristics in elite womens volleyball. J Strength Cond Res 24(9): 2316-2321, 2010-The aim of this study was to determine whether the in-game role of players (setter, outside, middle, or opposite player) in elite womens volleyball is significantly related to the characteristics of their service. The sample consisted of 1,300 service deliveries (total serves for all matches) made by players in the 8 teams participating in 2 Final 4 stages of the Indesit European Champions League. The variables recorded were in-game role of the server, service type, speed of delivery, service area, target zone, and effectiveness of delivery. Results showed a significant relation between the servers in-game role and service type (p ≤ 0.01), service speed (p ≤ 0.01), service area (p ≤ 0.01), and effectiveness of delivery (p ≤ 0.001). The most significant relation observed was with the service area, primarily because of the server having to make a quick transition to the defense zone. Setters and opposite players most commonly served from behind zone 1 (100 and 80% of serves, respectively), which they defended after serving. Similarly, middle players served most frequently from behind zone 5 (47% of serves), the zone they subsequently defended.

Heart rate variability during high-intensity exercise

The aim of this paper is to describe and analyse the behaviour of heart rate variability (HRV) during constant-load, high-intensity exercise using a time frequency analysis (Wavelet Transform). Eleven elite cyclists took part in the study (age: 18.6±3.0 years; VO2max: 4.88±0.61 litres·min−1). Initially, all subjects performed an incremental cycloergometer test to determine load power in a constant load-test (379.55±36.02 W; 89.0%). HRV declined dramatically from the start of testing (p <0.05). The behaviour of power spectral density within the LF band mirrored that of total energy, recording a significant decrease from the outset LF peaks fell rapidly thereafter, remaining stable until the end of the test. HF-VHF fell sharply in the first 20 to 30 seconds. The relative weighting (%) of HF-VHF was inverted with the onset of fatigue, [1.6% at the start, 7.1 (p <0.05) at the end of the first phase, and 43.1% (p <0.05) at the end of the test]. HF-VHFpeak displayed three phases: a moderate initial increase, followed by a slight fall, thereafter increasing to the end of the test. The LF/HF-VHF ratio increased at the start, later falling progressively until the end of the first phase and remaining around minimal values until the end of the test.

Study of mechanical characteristics of the knee extensor and flexor musculature of volleyball players

Abstract The aim of the present study was to analyse differences in muscle response and mechanical characteristics of the vastus medialis, rectus femoris, vastus lateralis, and biceps femoris in elite volleyball players of both sexes using tensiomyography. To this end, 47 players of nine nationalities playing for teams in the mens and womens Spanish Superleagues were assessed. The sample comprised 22 women (age 24.6±4.3 years; weight 72.14±10.06 kg; height 178.40±8.50 cm) and 25 men (age 25.0±4.3 years; weight 88.76±9.07 kg; height 194.71±7.84 cm). Tensiomyography was used to assess muscular response and muscular mechanical characteristics. For this purpose, the following variables were analysed: maximum radial displacement of muscle belly and normalized response speed. The findings show, both in men and women, a higher normalized response speed score in the vastus lateralis and vastus medialis compared with the rectus femoris and biceps femoris. A marked lateral symmetry of maximum radial displacement of the muscle belly was also observed in the musculature of the lower limbs, with no statistically significant differences being detected in either men or women. There were, however, clear differences in terms of normalized response speed between male and female volleyball players: women displayed a more pronounced difference in the normalized response speed of the musculature responsible for extension (vastus medialis, rectus femoris, and vastus lateralis) and flexion (biceps femoris) of the knee joint than men. Moreover, tensiomyography proved to be a highly sensitive tool for detecting such changes.

Effects of age and physical activity on response speed in knee flexor and extensor muscles

This study aims to determine the normalized response speed (Vrn) in vastus lateralis (VL) and biceps femoris (BF) muscles in different age groups using tensiomyography. Eighty-four male subjects were divided into four age groups: teenage subjects (T); undergraduate students (U), adult subjects (A), and the elderly group (E). Differences in Vrn were observed between E and T (p = 0.000), E and U (p = 0.000), and E and A (p = 0.018) for right VL and between E and T (p < 0.000) and U (p = 0.003) for left VL; between T and U (p = 0.010) and A (p = 0.000) for right VL, and A (p = 0.004) for left VL. Vrn in the BF displayed different behavior from that of the VL, increasing moderately or stabilizing and declining slightly in E, in right leg (p = 0.020). The data obtained highlighted a decline in Vrn for the VL in both legs with increasing age and, declines in BF response speed were observed only in E.

Evaluación de la respuesta muscular como herramienta de control en el campo de la actividad física, la salud y el deporte

Resumen La tensiomiografia es un metodo de evaluacion muscular desarrollado en la decada de los noventa en la Facultad de Ingenieria Electrica de la Universidad de Ljubliana (Eslovenia), bajo la direccion de Vojko Valencic. Mide la deformacion radial de un musculo cuando este es estimulado electricamente. La magnitud de estos cambios y el tiempo en el que se producen nos permiten obtener informacion sobre las caracteristicas mecanicas y la capacidad contractil de los musculos superficiales evaluados. El objetivo de este trabajo es hacer una revision actualizada de la produccion cientifica publicada y revisar los procedimientos metodologicos para su correcta aplicacion e interpretacion, aportando algunas reflexiones y propuestas que ayuden a sus usuarios y amplie la informacion disponible hasta el momento.

Characterisation of the Main Playing Variables Affecting the Service in High-Level Women's Volleyball

This study sought to establish the most important factors affecting the service in high-level women’s volleyball and the relative weighting of such factors on this technical part of the sport. A total of 1300 services from eight matches played in two Final Fours of the Indesit European Champions League were analysed. The services were delivered by 58 players of 25 nationalities. Observation sheets and two video cameras located at both ends of the court were used. Service speed was measured by radar. The twelve variables studied enabled the service to be divided into four components. The most influential component (19.02% of total variance) comprised variables related to technical service characteristics (type of service and service speed). The second most influential component (15.16% of variance) was related to the opponents’ technique and tactics, and to their position on court at the time of the service. The service was also affected by the technical and tactical movements that the servicer needed to perform in the subsequent play (12.20%). The stage of the match and the score (10.67%) also presented players with different levels of risk and helped to determine the type of service chosen and the power with which it was executed.

Study of extensor and flexor musculature in the knees of male and female volleyball players

Objective The aim of the present study was to analyse differences in muscle response and mechanical characteristics of the vastus medialis (VM), rectus femoris (RF), vastus lateralis (VL) and biceps femoris (BF) in elite volleyball players of both sexes using tensiomyography (TMG). Setting 47 players of nine nationalities playing in teams belonging to the mens and womens Spanish Superleagues (elite division) were assessed. Participants 22 women (age 24.59±4.27 years; weight 72.14±10.06 kg; height 178.40±8.50 cm) and 25 men (age 25.04±4.29 years; weight 88.76±9.07 kg; height 194.71±7.84 cm). Methods TMG was used to assess muscular response, muscular mechanical characteristics, and gender differences. For this purpose, the following variables were analysed: maximum radial displacement of muscle belly or maximum deformation (Dm), and normalised response speed (Vrn). Results The findings show, both in men and women, a higher normalised response speed (Vrn) score in the VL and VM compared to the RF and BF. A marked lateral symmetry of maximum radial deformation or displacement of the muscle belly (Dm) was also observed in the musculature of the lower limbs, with no statistically-significant differences being detected in either men or women. There were, however, clear differences in terms of muscle response between male and female volleyball players: women displayed a more pronounced difference in the Vrn of the musculature responsible for extension (VM, RF and VL) and flexion (BF) of the knee joint than men. Conclusions TMG proved to be a highly sensitive tool for detecting changes in lower limb muscle activity.

Effect of Hyperbaric Pressure During Scuba Diving on Autonomic Modulation of the Cardiac Response: Application of the Continuous Wavelet Transform to the Analysis of Heart Rate Variability

This study sought to determine the effects of hyperbaric pressure on heart rate modulation, by analyzing potential changes in heart rate variability (HRV). Ten divers were exposed to pressures of 1, 2, 3, and 4 atmospheres absolute (ATA). The test was performed in a hyperbaric chamber. Heart rate (HR) was recorded in supine subjects for 10 minutes per atmosphere. HRV was analyzed in the frequency mode (fast-Fourier transform and continuous wavelet transform). Results confirmed bradycardia as pressure increased. The drop in HR attained statistical significance after 2, 3, and 4 ATA. Signal energy (normalized TP values) rose progressively, becoming significant at 2 ATA. High frequency and low frequency displayed similar behavior in both cases. Although frequency band peaks did not yield clear results, continuous wave transform analysis showed that the frequency spectrum tended to shift into the high-frequency range as pressure increased. In summary, increased pressure prompted increased bradycardia, and HRV shifted into high-frequency range.