An exhaustive review has been made to filter the studies that have analyzed muscle function though tensiomyography (TMG) with elite or well-trained athletes. The results of this review indicate that the several protocols used in athletes to find the displacement-time curve with greater maximum radial muscle displacement showed a good-excellent reliability. TMG has been used to characterize athletes' muscles contractile properties from specific sports disciplines, although there are very few sports that have been deeply analyzed. TMG seems to be useful to determine changes in muscles contractile properties after stimuli of competition, training or recovery. These changes have been strongly related with the fatigue produced after an effort. In addition, TMG parameters could be used to control training effects during a specific period or throughout the season being also a very useful tool to individualize athletes training loads. In this sense, it also seems to provide sports performance information in cyclic sports by relating some TMG parameters with performance indicators. On the other hand, the TMG-BCM algorithm has been used as a lateral and functional symmetry measure and as a monitoring tool for injury prevention and recovery. However, it seems to be no clear criterion that determines asymmetry degree, nor established contractile properties values as a reference to prevent or recover sports injuries. Despite the utility shown in these fields, there are still very few sports analyzed and it is really necessary to continue advancing in the knowledge of the contractile properties behavior, such as the effects of athletes' training, competitions and injuries and even in the parameters interpretation obtained with the TMG.

/pdf/clinical-utility-of-tensiomyography-for-muscle-function-2iwlrds7ln.pdf

Clinical utility of tensiomyography for muscle function analysis in athletes.

Sella, FS, McMaster, DT, Beaven, CM, Gill, ND, and Hebert-Losier, K. Match demands, anthropometric characteristics, and physical qualities of female rugby sevens athletes: A systematic review. J Strength Cond Res 33(12): 3463-3474, 2019-Since the inclusion of rugby sevens in the 2016 Olympic Games, the popularity of women's rugby sevens has grown rapidly worldwide. This systematic review aimed to summarize the scientific literature addressing the match demands, anthropometric characteristics, and physical qualities of female rugby sevens athletes and to highlight differences between competition levels and playing positions. Four electronic databases were searched, as were the reference lists and key journals. Hedges' g effect sizes with 95% confidence intervals were calculated to evaluate differences between elite and nonelite athletes, and backs and forwards. Twenty-seven studies met inclusion criteria and scored 68 ± 13% upon quality assessment. Comparisons between groups were restricted to variables where data were available. Greater running demands and intensities, number of sprints and accelerations, but lower physiological responses characterized international matches compared with nationals. At international level, backs demonstrated greater running demands and intensities, number of sprints, and physiological responses than forwards. Elite athletes were leaner, taller, and displayed superior physical qualities (e.g., maximal speed, power, upper-body strength, and aerobic capacity) compared with nonelite athletes. At elite level, forwards were heavier and displayed greater upper-body strength, whereas backs showed greater acceleration and maximal speed abilities. The specific match demands and physical requirements of female rugby sevens athletes competing at different playing levels and playing positions must be considered for developing effective training programs.

/pdf/match-demands-anthropometric-characteristics-and-physical-3bke6a2rdu.pdf

Match Demands, Anthropometric Characteristics, and Physical Qualities of Female Rugby Sevens Athletes: A Systematic Review

Skeletal muscle is considered as a near-constant volume system, and the contractions of the muscle are related to the changes in tissue thickness Assessment of the skeletal muscle contractile parameters such as maximum contraction thickness ( T h ), contraction time ( T c ), contraction velocity ( V c ), sustain time ( T s ), and half-relaxation ( T r ) provides valuable information for various medical applications This paper presents a single-element wearable ultrasonic sensor (WUS) and a method to measure the skeletal muscle contractile parameters in A-mode ultrasonic data acquisition The developed WUS was made of double-layer polyvinylidene fluoride (PVDF) piezoelectric polymer films with a simple and low-cost fabrication process A flexible, lightweight, thin, and small size WUS would provide a secure attachment to the skin surface without affecting the muscle contraction dynamics of interest The developed WUS was employed to monitor the contractions of gastrocnemius (GC) muscle of a human subject The GC muscle contractions were evoked by the electrical muscle stimulation (EMS) at varying EMS frequencies from 2 Hz up to 30 Hz The tissue thickness changes due to the muscle contractions were measured by utilizing a time-of-flight method in the ultrasonic through-transmission mode The developed WUS demonstrated the capability to monitor the tissue thickness changes during the unfused and fused tetanic contractions The tetanic progression level was quantitatively assessed using the parameter of the fusion index (FI) obtained In addition, the contractile parameters ( T h , T c , V c , T s , and T r ) were successfully extracted from the measured tissue thickness changes In addition, the unfused and fused tetanus frequencies were estimated from the obtained FI-EMS frequency curve The WUS and ultrasonic method proposed in this study could be a valuable tool for inexpensive, non-invasive, and continuous monitoring of the skeletal muscle contractile properties

Ultrasound Measurement of Skeletal Muscle Contractile Parameters Using Flexible and Wearable Single-Element Ultrasonic Sensor.

Purpose To examine the variations in the velocity of contraction (Vc) assessed using tensiomyography, vertical jumping ability, and sprinting speed induced by 4 different exercise protocols (ie, strength, sprint, plyometric, and technical training sessions) in 14 male national-team rugby players (age 21.8 [2.6] y, weight 83.6 [8.5] kg, and height 177.4 [6.7] cm). Methods Physical tests were conducted immediately before and after 4 distinct workouts in the following order: tensiomyography in the rectus femoris and biceps femoris muscles, squat and countermovement jumps, and 30-m sprint velocity. To analyze the differences in the assessed variables before and after each training session, the differences based on magnitudes were calculated. Results After strength and plyometric workouts, the players presented possible to almost certain impairments in sprint and jump performance and in the Vc of the rectus femoris (effect sizes 0.26-0.64). After the sprint-training session, possible to very likely decreases were observed in the squat jump, 30-m sprint, and Vc of the biceps femoris (effect sizes 0.21-0.44). By contrast, after the technical training, athletes demonstrated a possible increase in the squat jump and Vc in both muscles examined (effect sizes 0.13-0.20). Conclusions The main finding of this research is that, for the vast majority of results, the direction of changes observed in Vc were the same as those observed in performance assessments. This suggests that Vc might be used as a sensitive marker of acute variations in speed and power performance of elite team-sport athletes.

Is Tensiomyography-Derived Velocity of Contraction a Sensitive Marker to Detect Acute Performance Changes in Elite Team-Sport Athletes?

The aim of the study was to determine the effect of α-actinin-3 (ACTN3) deficiency (XX) on muscle damage induced by an eccentric exercise bout. In this purpose, 4 RR and 4 XX individuals performed ...

The stiffness response of type IIa fibres after eccentric exercise-induced muscle damage is dependent on ACTN3 r577X polymorphism.

This study aimed to determine which contractile properties measured by tensiomyography (TMG) could better differentiate athletes with high- and low-power values, as well as to analyse the relations...

Rocio Dominguez-Castells

Papers

Relationship between skeletal muscle contractile properties and power production capacity in female Olympic rugby players

Preconditioning Ischemia Decreases Temperature and Impairs Muscle Contractile Properties: 2879 Board #2 June 3, 1: 00 PM - 3: 00 PM.