Changes in the Force-Velocity Mechanical Profile After Short Resistance Training Programs Differing in Set Configurations.

The main aim of this study was to analyze the effect of resistance training programs differing in set configuration on mechanical force-velocity profiles. Thirteen participants performed 10 unilateral knee extension training sessions over 5 weeks. Each limb was randomized to one of the following set configurations: traditional (4 sets of 8 repetitions at maximum intended velocity, 10RM load, 3-min pause between sets) or interrepetition rest (32 maximum intended velocity repetitions, 10RM load, 17.4 s of rest between each repetition). Velocity of each repetition was recorded throughout the program. Before and after training, individual linear force velocities were calculated, and the following parameters were obtained: force and velocity axis intercept, slope, and estimated maximum power. Mean velocity was higher throughout the program for interrepetition rest configuration (0.54 ± 0.01 vs. 0.48 ± 0.01 m∙s-1 for interrepetition rest, and traditional configuration respectively; main effect of set configuration: P < .001). There was a significant increase in force and velocity intercepts, but a steeper negative slope after both training protocols (main effect of time: P < .001 for every variable). Differences in resistance training velocity did not affect the adaptations. Our results suggest that, in a short-term program, maximum intended rather than actual velocity is a key factor to modulate strength adaptations.

Inter-repetition rest training and traditional set configuration produce similar strength gains without cortical adaptations.

This study compared the functional and neural effects of two strength training programmes differing in set configuration. Thirteen participants performed 10 sessions, over a period of 5 weeks, of unilateral leg extensions with different set configurations but with identical work-to-rest ratios for each limb: a traditional configuration (4 sets of 8 repetitions, 10RM load, 3-min pause between sets) and an inter-repetition rest configuration (32 repetitions, 10RM load, 17.4 s of rest between each repetition). Mean propulsive velocity of the traditional sessions was lower than for inter-repetition rest sessions (0.48 ± 0.06 vs. 0.54 ± 0.06 m · s(-1); P < 0.001), while perceived exertion was higher (8.3 ± 0.9 and 6.56 ± 1.6 for traditional training and IRT; P = 0.002). One repetition maximum (RM), work with 10RM load, maximum mean propulsive power, maximum voluntary contraction and time to failure with 50% of maximum isometric force improved similarly in both legs (time effect, P < 0.001; effect size range, 0.451-1.190). Time and set configuration did not show significant main effects or interactions for cortical adaptations (motor-evoked potentials, short-interval intracortical inhibition, intracortical facilitation). There were no significant correlations between changes in cortical and peripheral neural adaptations and strength improvement. In conclusion, inter-repetition rest configuration was as effective as traditional training in improving muscle performance.

Handball Training and Competition With Facemasks in Galicia: The FISICOVID-DXTGALEGO Protocols Experience.

Objective: COVID-19 caused a complete stop in non-professional sports. The use of face masks for team sports is not a widely used measure in non-professional sports. The study aimed to evaluate the perception about using the mask and the adaptation difficulties related to training and competition in team sports following the FISICOVID-DXTGALEGO protocol. Methods: Seven hundred eighty-seven handball players from the Galician Handball Federation were followed during their return to participation after months of confinement through an electronic questionnaire of perception and experience on the use of a mask. Results: There is an excellent adaptation to the mask in training and competition with medium and high correlations. The 86,41% of players reported an adaptation to the mask in 3 weeks with a three times a week training frequency. The negative opinion on the mask was drastically reduced (-66.86%) after use. The 80,44% of players considered the use of a mask as an essential measure to resume competitions. Conclusions: It is very feasible to adapt to training and compete with a mask (hygienic or surgical) in a short period. The use of a mask following these protocols changed previous opinions on the disadvantages of the mask during training and competition.

Perception of the Sports Social Environment After the Development and Implementation of an Identification Tool for Contagious Risk Situations in Sports During the COVID-19 Pandemic.

This study details the methodological process for creating a tool for the identification of COVID-19 potential contagion situations in sports and physical education before, during, and after practice and competition. It is a tool that implies an educational and methodological process with all the agents of the sports system. This tool identifies the large number of interactions occurring through sports action and everything that surrounds it in training, competition, and organization. The aim is to prepare contingency protocols based on an exhaustive analysis, risk detection, and proposal of contingency measures trying to reduce the residual risk to a minimum. In the second part, the results of the implementation of this tool in the sports system of Galicia (Spain) are shown. The technicians have changed their perceptions about the coronavirus transmission in sports. They highlight the problem for returning to sports participation for athletes under 18 years in the pandemic context.

[Identification tool for potential infectious situations in sport: FISICOVID-DXTGALEGO (Xunta de Galicia).] / Herramienta de identificación de situaciones de contagio en el deporte: FISICOVID-DXTGALEGO (Xunta de Galicia).

This work details the creation, development and integration of the FISICOVID-DXTGALEGO tool. Its main objective is to detect situations of potential contagion of COVID-19 in sport, as well as to propose contingency measures trying to reduce residual risk to a minimum. This article describes the operation of the tool within the sports system of the autonomous community of Galicia, made up of 300 sports specialties in 58 regional federations collaborating with the regional sports administration (Secretaría Xeral para o Deporte, Xunta de Galicia). It is a tool that implies a methodological and educational process with all the agents of the sports system to identify the large number of interactions that occur in sports action and everything that surrounds it in training, competition and its organization.

Este trabajo detalla la creación, desarrollo e integración de la herramienta FISICOVID-DXTGALEGO. Su principal objetivo es detectar situaciones de potencial contagio de la COVID-19 en el deporte, así como proponer medidas de contingencia intentando reducir el riesgo residual al mínimo. En el presente artículo se describe el funcionamiento de la misma dentro del sistema deportivo de la comunidad autónoma de Galicia, conformado alrededor de 300 especialidades deportivas en 58 federaciones autonómicas colaborando con la Secretaría Xeral para o Deporte. Se trata de una herramienta que lleva implícito un proceso metodológico y educativo con todos los agentes del sistema deportivo para identificar el gran número de interacciones que se dan en la acción deportiva y todo lo que la rodea en el entrenamiento, la competición y su organización.

Perception of the Sports Social Environment After the Development and Implementation of an Identification Tool for Contagious Risk Situations in Sports During the COVID-19 Pandemic.

The present work details the methodological process for creating a tool for the identification of COVID-19 potential contagion situations in sport and physical education before, during, and after practice and competition. It is a tool that implies an educational and methodological process with all the agents of the sports system. This tool identifies the large number of interactions occurring through sports action and everything that surrounds it in training, competition, and its organization. The aim is to prepare contingency protocols based on an exhaustive analysis, risk detection, and proposal of contingency measures trying to reduce the residual risk to a minimum. In a second part, the results of the implementation of this tool in the sports system of Galicia (Spain) are shown revealing the change in perception about the coronavirus transmission in sport of the technicians and the problem for returning to sport for athletes under 18 years.

Short-Term Effects of Anodal Transcranial Direct Current Stimulation on Endurance and Maximal Force Production. A Systematic Review and Meta-Analysis.

The purpose of the present systematic review and meta-analysis was to explore the effects of transcranial direct current stimulation (tDCS) on endurance (i.e., time to task failure (TTF)) and maximal voluntary contraction (MVC). Furthermore, we aimed to analyze whether the duration of stimulation, the brain region targeted for stimulation, and the task performed could also influence motor performance. We performed a systematic literature review in the databases MEDLINE and Web of Science. The short-term effects of anodal tDCS and sham stimulation (placebo) were considered as experimental and control conditions, respectively. A total of 31 interventions were included (MVC = 13; TTF = 18). Analysis of the strength-related tDCS studies showed small improvements in the MVC (SMD = 0.19; 95% CI = -0.02, 0.41; p = 0.08). However, the results of the endurance-related interventions indicated a moderate effect on TTF performance (SMD = 0.26; 95% CI = 0.07, 0.45; p = 0.008). Furthermore, the sub-analysis showed that anodal tDCS over M1 and stimulation durations longer than 10 min produced the best results in terms of TTF performance enhancement. Additionally, the effects of anodal tDCS were larger during full body exercises (i.e., cycling) when compared to uniarticular tasks. In conclusion, the current meta-analysis indicated that anodal tDCS leads to small and moderate effects on MVC and TTF, respectively.

Acute neuromechanical modifications and 24-h recovery in quadriceps muscle after maximal stretch-shortening cycle exercise.

In the present study we investigated the acute and the delayed changes in corticospinal excitability and in the neuromechanical properties of the quadriceps muscle after maximal intensity stretch-shortening cycle exercise. Ten young males performed 150 jumps to provoke fatigue and muscle damage. Voluntary force, various electrically evoked force variables, and corticospinal excitability were measured at baseline, immediately (IP) and at 24 h post-exercise. Voluntary force, single twitch force, and low frequency force decreased at IP (p < 0.05) but recovered at 24 h, although mild soreness developed in the quadriceps. High frequency force, voluntary activation, and corticospinal excitability remained unchanged. However, vastus lateralis myoelectric activity increased from baseline to IP (p < 0.05). The jumps selectively induced low frequency peripheral fatigue, and central mechanisms did not mediate the acute loss of voluntary force. Because soreness developed at 24 h post-exercise, all force variables recovered, and vastus lateralis electric activity increased, we argue that a dual process of muscle damage, and early neural adaptation as a compensation mechanism took place after the maximal stretch-shortening cycle exercise.

Athletes versus video game players: A predictive contextual processing study.

We investigated the effect of abstract and real life meaningful images from sports on predictive contextual processing in professional athletes and video gamers. EEG was recorded in three groups: professional basketball players (BP), professional athletes of individual sports (IA) and experienced action video game players (VG). Two recording sessions, each with a different set of visual stimuli was presented: either triangles facing left, up, right or down or four images of a basketball player throwing a ball. Recording blocks consisted of targets preceded by randomized sequences of standards and by sequences including a predictive sequence signaling the occurrence of a subsequent target event. The gradual increase of P3b amplitudes across the predictive sequence was greater in BP compared with VG, when stimuli consisted of real life images of a basketball player. For the basketball session, we observed increased local modularity and stronger functional connectivity within frontal attentional networks in BP and VG compared with IA, during the processing of the predictive sequence. Our findings suggest increased top-down attentional allocation, during the processing of predictive visual stimuli, in basketball players compared with video gamers and individual sports athletes.

Modulation of quadriceps corticospinal excitability by femoral nerve stimulation.

INTRODUCTION: We explored the conditioning effect of a percutaneous electrical pulse of the femoral nerve on cortical motor evoked responses in the rectus femoris muscle. METHODS: Corticospinal excitability of rectus femoris muscle was measured in sixteen healthy subjects, when a single transcranial magnetic pulse was preceded by an electrical femoral nerve stimulus, using twelve inter-stimulus intervals (from 10 to 275ms). We also evaluated the effects of the intensities of the transcranial magnetic and of the electrical pulses. RESULTS: Quadriceps motor evoked potentials were inhibited and facilitated when a single femoral nerve electrical stimulus was delivered at inter-stimulus intervals of 25ms and 150ms, respectively. The facilitation was reduced when low electrical intensity was used, while the inhibition decreased with high intensity transcranial magnetic pulse. CONCLUSION: Afferent inputs of a femoral stimulation modulate the responses elicited by transcranial magnetic pulses of the contralateral quadriceps motor cortex. This modulation indicates a sensorimotor integration of proximal lower limb muscles that may be mediated via different types of afferents. This could be of relevance for studies that explore the role of lower limb muscles in postural control and balance.

Set Configuration in Resistance Exercise: Muscle Fatigue and Cardiovascular Effects.

PURPOSE: Cardiovascular responses of traditional resistance (TS) training have been extensively explored. However, the fatigue mechanisms associated with an intra-set rest configuration (ISR) have not been investigated. This study compares two modalities of set configurations for resistance exercise that equates work to rest ratios and measures the central and peripheral fatigue in combination with cortical, hemodynamic and cardiovascular measures. METHODS: 11 subjects performed two isometric knee extension training sessions using TS and ISR configurations. Voluntary activation (VA), single twitch amplitude, low frequency fatigue (LFF), Mwave, motor evoked potential (MEP), short intracortical inhibition (SICI), intracortical facilitation (ICF) and heart rate variability were evaluated before and after each training session. During each session beat to beat heart rate, blood pressure and rate pressure product (RPP) were also evaluated. RESULTS: After exercise VA decreased significantly for TS but not for ISR (P < 0.001), single twitch amplitude and LFF values were lower for TS than ISR (P < 0.004), and SICI was reduced only for the TS configuration (P = 0.049). During exercise RPP values were significantly higher for the TS than for ISR (P = 0.001). RPP correlated with VA for TS (r = -.85 P < 0.001) suggesting a relationship between central fatigue and cardiovascular stress. CONCLUSIONS: We conclude that ISR induced lower central and peripheral fatigue as well as lower cardiovascular stress in comparison with TS configuration. Our study suggests that set configuration is a key factor in the regulation of the neuromuscular and cardiovascular responses of resistance training.

Inter-individual variability in response to non-invasive brain stimulation paradigms.

BACKGROUND: Non-invasive Brain Stimulation (NIBS) paradigms are unique in their ability to safely modulate cortical plasticity for experimental or therapeutic applications. However, increasingly, there is concern regarding inter-individual variability in the efficacy and reliability of these paradigms. HYPOTHESIS: Inter-individual variability in response to NIBS paradigms would be better explained if a multimodal distribution was assumed. METHODS: In three different sessions for each subject (n = 56), we studied the Paired Associative Stimulation (PAS25), Anodal transcranial DC stimulation (AtDCS) and intermittent theta burst stimulation (iTBS) protocols. We applied cluster analysis to detect distinct patterns of response between individuals. Furthermore, we tested whether baseline TMS measures (such as short intracortical inhibition (SICI), resting motor threshold (RMT)) or factors such as time of day could predict each individual's response pattern. RESULTS: All three paradigms show similar efficacy over the first hour post stimulation--there is no significant effect on excitatory or inhibitory circuits for the whole sample, and AtDCS fares no better than iTBS or PAS25. Cluster analysis reveals a bimodal response pattern--but only 39%, 45% and 43% of subjects responded as expected to PAS25, AtDCS, and iTBS respectively. Pre-stimulation SICI accounted for 10% of the variability in response to PAS25, but no other baseline measures were predictive of response. Finally, we report implications for sample size calculation and the remarkable effect of sample enrichment. CONCLUSION: The implications of the high rate of 'dose-failure' for experimental and therapeutic applications of NIBS lead us to conclude that addressing inter-individual variability is a key area of concern for the field.

Startle auditory stimuli enhance the performance of fast dynamic contractions.

Fast reaction times and the ability to develop a high rate of force development (RFD) are crucial for sports performance. However, little is known regarding the relationship between these parameters. The aim of this study was to investigate the effects of auditory stimuli of different intensities on the performance of a concentric bench-press exercise. Concentric bench-presses were performed by thirteen trained subjects in response to three different conditions: a visual stimulus (VS); a visual stimulus accompanied by a non-startle auditory stimulus (AS); and a visual stimulus accompanied by a startle auditory stimulus (SS). Peak RFD, peak velocity, onset movement, movement duration and electromyography from pectoralis and tricep muscles were recorded. The SS condition induced an increase in the RFD and peak velocity and a reduction in the movement onset and duration, in comparison with the VS and AS condition. The onset activation of the pectoralis and tricep muscles was shorter for the SS than for the VS and AS conditions. These findings point out to specific enhancement effects of loud auditory stimulation on the rate of force development. This is of relevance since startle stimuli could be used to explore neural adaptations to resistance training.