Acute effects of jaw clenching while wearing a customized bite-aligning mouthguard on muscle activity and force production during maximal upper body isometric strength.

Background/objectives: The possible mechanisms supporting the relationship between the masticatory and the musculoskeletal systems have been recently investigated. It has been suggested that jaw clenching promotes ergogenic effects on prime movers through the phenomenon of concurrent activation potentiation (CAP). The purpose of this study was to analyse the effects of jaw clenching and jaw clenching while wearing mouthguard (MG) on muscle activity and force output during three upper body isometric strength tests. Methods: Twelve highly trained rink-hockey athletes were recruited for the study. A randomized, repeated measures within study design was carried out to compare the acute effects of three experimental conditions: jaw clenching while wearing MG (MG), jaw clenching without MG (JAW) and non-jaw clenching (NON-JAW). Results: Statistical analyses revealed significant higher force output (p < 0.05) in all tests for MG conditions with respect to NON-JAW. When comparing JAW and NON-JAW conditions an increased peak force was found in handgrip (p = 0.045, d = 0.26) and bench press (p = 0.018, d = 0.43) but not in biceps curl (p = 0.562, d = 0.13). When comparing MG and JAW conditions, no differences were observed in any force output. In terms of muscle activity, significant differences were found in the agonist muscles of the handgrip test for MG with respect to NON-JAW (p = 0.031-0.046, d = 0.25-1.1). Conclusion: This study demonstrated that jaw clenching, with and without MG, may be a good strategy to elicit the CAP phenomenon, which seems to promote ergogenic effects in upper body isometric force production. The non-significant differences observed between JAW and MG suggested that the use of MG doesn't make a difference in enhancing the isometric force production neither the muscle activity in upper body isometric strength.

Superimposed vibration on suspended push-ups.

Background: Superimposition of vibration has been proposed in sports training using several devices and methods to enhance muscle activation and strength adaptations. Due to the popularity of suspension training, vibration systems have recently been developed to increase the effects of this training method. The present cross-sectional study aims to examine the effects of superimposing vibration on one of the most popular exercises in strength and conditioning programs: push-ups. Methods: Twenty-eight physically active men and women executed push-ups in three suspended conditions (non-vibration, vibration at 25 Hz, and vibration at 40 Hz). OMNI-Res scale was registered, and surface electromyographic signals were measured for the activity of the right and left external oblique, anterior deltoid, triceps brachii, sternal, and clavicular heads of the pectoralis major. Results: A linear mixed model indicated a significant fixed effect for vibration at 25 Hz and 40 Hz on muscle activity. Suspended push-ups with superimposed vibration (25 Hz and 40 Hz) showed a significant higher activity on left (25 Hz: p = 0.036, d = 0.34; 40 Hz: p = 0.003, d = 0.48) and right external oblique (25 Hz: p = 0.004, d = 0.36; 40 Hz: p = 0.000, d = 0.59), anterior deltoid (25 Hz: p = 0.032, d = 0.44; 40 Hz: p = 0.003, d = 0.64), and global activity (25 Hz: p = 0.000, d = 0.55; 40 Hz: p = 0.000, d = 0.83) compared to non-vibration condition. Moreover, OMNI-Res significant differences were found at 25 Hz (6.04 ± 0.32, p = 0.000 d = 4.03 CI = 3.27, 4.79) and 40 Hz (6.21 ± 0.36 p = 0.00 d = 4.29 CI = 3.49, 5.08) compared to the non-vibration condition (4.75 ± 0.32). Conclusion: Superimposing vibration is a feasible strategy to enhance the muscle activity of suspended push-ups.

The Influence of Individual Set-Pieces in Elite Rink Hockey Match Outcomes.

The main objective of this study was to analyze the influence of individual set-pieces (Free Direct Hits and Penalties) in elite rink hockey match outcomes in different game situations. A sample of 161 matches played between high-standard teams during ten consecutive seasons (2009-2010 to 2018-2019) were analyzed using a binary logistic regression. The full evaluated model was composed of an explanatory variable (set-pieces scored) and five potential confounding and interaction variables (match location, match level, match importance, extra time, and balanced score). However, the final model only included one significant interaction variable (balanced score). The results showed that scoring more individual set-pieces than the opponent was associated with victory (OR = 6.1; 95% CI: 3.7, 10.0) and was more relevant in unbalanced matches (OR = 19.5; 95% CI: 8.6, 44.3) than in balanced matches (OR = 2.3; 95% CI: 1.2, 4.5). These findings indicate that individual set-pieces are strongly associated with match outcomes in matches played between high-standard teams. Therefore, it is important for teams to excel in this aspect, and it is suggested that these data can encourage coaches to reinforce the systematic practice of individual set-pieces in their training programs. Additionally, it is suggested that teams have specialist players in this kind of action to mainly participate in these specific match moments.

Effects of wearing a customized bite-aligning mouthguard on powerful actions in highly trained swimmers.

BACKGROUND/OBJECTIVES: The potential advantages of wearing customized bite-aligning mouthguards on several performance parameters such as muscular strength, power and reaction time have been reported. Literature shows that the concurrent activation potentiation phenomenon, elicited by a powered and balanced jaw clenching, can provide athletes with several neuromuscular advantages. The aim of the present study was to investigate the acute effects of jaw clenching while wearing a customized bite-aligning mouthguard on swimming start, countermovement jump and swim bench test, in contrast to two other conditions: non-jaw clenching and jaw clenching without mouthguard. METHODS: A randomized, repeated measure within study design was used to compare the condition effect on eight highly trained elite male and female swimmers. RESULTS: Statistical analysis revealed a significant increase in the countermovement jump height (p = 0.041) when comparing the use of mouthguards with the non-jaw condition. In the swim bench, a significant greater time to peak force (p = 0.049) was found when comparing the use of mouthguards with the jaw condition. Although, non-significant effects, small differences were found in the start reaction time and 15-m freestyle swimming when comparing the use of mouthguards with the non-jaw condition. CONCLUSION: This study demonstrated that wearing customized, bite-aligning mouthguards had an ergogenic effect on specific measures of vertical jump and swim bench test, whereas non-meaningful but small differences were found in swimming start.

sEMG Activity in Superimposed Vibration on Suspended Supine Bridge and Hamstring Curl.

Traditionally in strength and conditioning environments, vibration has been transmitted using platforms, barbells, dumbbells, or cables but not suspension devices. This study aimed to examine the effects on the lower limb of applying superimposed vibration on a suspension device. Twenty-one physically active men and women performed supine bridge and hamstring curl exercises in three suspended conditions (non-vibration, vibration at 25 Hz, and vibration at 40 Hz). In each exercise condition, the perceived exertion scale for resistance exercise (OMNI-Res) was registered, and the electromyographic signal was assessed for gastrocnemius (medialis and lateralis), biceps femoris, semitendinosus, gluteus maximus, and rectus femoris. A linear mixed model indicated a significant fixed effect for vibration at 25 Hz and 40 Hz on muscle activity in suspended supine bridge (p < 0.05), but no effect for suspended hamstring curl (p > 0.05). Likewise, the Friedman test showed a significant main effect for vibration at 25 Hz and 40 Hz in suspended supine bridge (p < 0.05) but not for suspended hamstring curl (p > 0.05) on OMNI-Res. Post hoc analysis for suspended supine bridge with vibration at 25 Hz showed a significant activation increase in gastrocnemius lateralis (p = 0.008), gastrocnemius medialis (p = 0.000), semitendinosus (p = 0.003) activity, and for semitendinosus under 40 Hz condition (p = 0.001) compared to the non-vibration condition. Furthermore, OMNI-Res was significantly higher for the suspended supine bridge at 25 Hz (p = 0.003) and 40 Hz (p = 0.000) than for the non-vibration condition. Superimposed vibration at 25 Hz elicits a higher neuromuscular response during the suspended supine bridge, and the increase in vibration frequency also raises the OMNI-Res value.

Assessing the Magnitude and Direction of Asymmetry in Unilateral Jump and Change of Direction Speed Tasks in Youth Female Team-Sport Athletes.

The direction of inter-limb asymmetries and the change of direction (COD) deficit are two aspects that have increased in recent years. The main objective of the present study was to assess the magnitude of neuromuscular asymmetries in an elite youth female team-sports sample and determine its directionality. Secondary objectives were to evaluate the relationship between COD deficit, linear speed and COD time performance. Elite female youth basketball and handball players (n = 33, age = 16 ± 1.17 y) performed the Single Leg Countermovement Jump in vertical (SLCJ-V), horizontal (SLCJ-H), and lateral (SLCJ-L) directions, the COD and the 10-m sprint. Results showed statistical differences between limbs in all the neuromuscular tests (p < 0.001). The Kappa coefficient showed poor to fair levels of agreement between tasks (K range = -0.087 to 0.233), indicating that asymmetries rarely favoured the same limb between skills. Additionally, small and non-significant correlations were found between the linear sprint capacity and the COD ability. The findings of the present study highlight the independent directionality of asymmetries across tests. The COD deficit does not appear to be much more advantageous than COD total time to measure asymmetry. Practitioners are encouraged to use a fitness testing battery to detect existing side differences and each ability should be specifically trained with functional tasks.

Analysis of the Individual Set-Pieces Influence on the Teams' Ranking in Rink Hockey.

The main objective of this research was to analyze the individual set-pieces influence on the final season ranking in rink hockey. For this purpose, 6,920 individual set-pieces from 1,680 matches corresponding to free direct hits (n = 4,332) and penalty shots (n = 2,588) were analyzed during seven consecutive seasons (2012-13 to 2018-19) in the First Spanish League (Ok Liga). The variables recorded were the following for each team: total points, free direct hits attempted, free direct hits scored, penalties attempted, penalties scored, total goals scored during the season, free direct hits received, goals received from free direct hits, penalties received, goals received from penalties and total goals received in the season. Results showed that 21.08% of the goals were scored by free direct hits and penalty shots (11.58% and 9.49%, respectively). Likewise, teams ranked in a better position achieved higher effectiveness in individual set-pieces and their goalkeepers were more effective in defending the free direct hits and penalties. Furthermore, results showed significant correlations between team season points and better performance in individual set-pieces variables. Therefore, the results of this study demonstrated the importance of systematic practice of free direct hits and penalty shots for teams' success in rink hockey. Additionally, it is suggested that teams possess special players to execute these particular elements of match play.

Acute Effects of Wearing Bite-Aligning Mouthguards on Muscular Strength, Power, Agility and Quickness in a Trained Population: A Systematic Review.

The purpose of the present systematic review was to determine the acute effects of wearing bite-aligning mouthguards on muscle strength, power, agility and quickness in athletes. A search of the current literature was performed using the electronic databases (until 1 May 2021) Web of Science, Scopus and Medline. The inclusion criteria were: (1) descriptive design studies; (2) with randomized clinical trials; (3) examining the within-subject acute effects of wearing mouthguards on functional and neuromuscular performance parameters; (4) in physical active, recreational or high-standard athletes. Twenty-seven studies met the inclusion criteria. Sixteen reported positive effects in some of the variables assessed, two reported negative effects and the rest found no significant differences. Overall, the main findings described in the literature are inconclusive concerning the neuromuscular advantages of using mouthguards in muscle strength, power, agility and quickness. These discrepancies might be related to several factors such as differences in testing protocols, poor control of the jaw magnitude and improper mouthguard designs. Despite these differences, after conducting the present systematic review, the authors speculate that jaw clenching while wearing custom-made, bite-aligning oral devices might promote beneficial effects in lower limb power actions, especially in jump ability and knee extension movements. Thus, athletes might consider the use of mouthguards, not only for their protective role but also for the potential ergogenic effects in specific actions, mainly those for which lower limb muscular power are required.

Predicting the Unknown and the Unknowable. Are Anthropometric Measures and Fitness Profile Associated with the Outcome of a Simulated CrossFit® Competition?

The main objective of this research was to find associations between the outcome of a simulated CrossFit® competition, anthropometric measures, and standardized fitness tests. Ten experienced male CrossFit® athletes (age 28.8 ± 3.5 years; height 175 ± 10.0 cm; weight 80.3 ± 12.5 kg) participated in a simulated CrossFit® competition with three benchmark workouts ("Fran", "Isabel", and "Kelly") and underwent fitness tests. Participants were tested for anthropometric measures, sit and reach, squat jump (SJ), countermovement jump (CMJ), and Reactive Strength Index (RSI), and the load (LOAD) corresponding to the highest mean power value (POWER) in the snatch, bench press, and back squat exercises was determined using incremental tests. A bivariate correlation test and k-means cluster analysis to group individuals as either high-performance (HI) or low performance (LO) via Principal Component Analysis (PCA) were carried out. Pearson's correlation coefficient two-tailed test showed that the only variable correlated with the final score was the snatch LOAD (p < 0.05). Six performance variables (SJ, CMJ, RSI, snatch LOAD, bench press LOAD, and back squat LOAD) explained 74.72% of the variance in a k = 2 means cluster model. When CrossFit® performance groups HI and LO were compared to each other, t-test revealed no difference at a p ≤ 0.05 level. Snatch maximum power LOAD and the combination of six physical fitness tests partially explained the outcome of a simulated CrossFit competition. Coaches and practitioners can use these findings to achieve a better fit of the practices and workouts designed for their athletes.

A comparison between predetermined and self-selected approaches in resistance training: effects on power performance and psychological outcomes among elite youth athletes.

BACKGROUND: The aim of this study was to investigate if choice over resistance training exercise order affects motor performance and psychological outcomes among elite youth hockey players. METHODS: Seventeen elite hockey players (male, n = 14; female, n = 3, age: 15.1 ± 1.1 years) participated in this study. In the first session, individual optimum power loads were calculated in the back squat, jump squat, bench press and bench throw exercises. Then, in four counterbalanced sessions, participants completed three sets of six repetitions in the same exercises loaded with their optimum power loads. In two sessions, athletes used a self-selected order of exercises, while in other two sessions the order was predetermined. Power outputs were estimated with a linear position transducer. Fatigue and enjoyment were measured during and after the sessions using standardized questionnaires. Repeated measures analyses of variance and a paired-sample t-test were used to compare the effects between conditions. RESULTS: We observed trivial to small differences between conditions in power outputs (p ≥ 0.07; ES ≤ 0.21), fatigue (p ≥ 0.42; ES ≤ 0.33) and enjoyment (p = 0.72; ES = 0.05). CONCLUSION: Given the comparable effects between approaches, both can be used when coaching youth athletes. Self-selecting the order of exercises based on preferences is a feasible and practical coaching option when working with youth athletes.

Temporal trend of cardiorespiratory endurance in urban Catalan high school students over a 20 year period.

BACKGROUND: Physical fitness is considered an important indicator of health in adolescents. However, in recent years several studies in the scientific literature have shown a considerable lower trend and an alarming worsening of the current adolescents' physical condition when comparing with previous decades, especially in urban populations. The aim of the current study was to analyse the temporal trend in cardiorespiratory endurance (CRE) in urban Catalan adolescents over a 20-year period (1999-2019). METHODS: A cross-sectional analysis study considering the 20-m Shuttle Run test (SRT) results obtained in the last 20 years was carried out. 1,701 adolescents between 15 and 16 years old (914 boys and 787 girls) were divided into four groups, corresponding to consecutive periods of five years (Group 1: 1999-2004; Group 2: 2005-2009; Group 3: 2010-2014 and Group 4: 2015-2019). ANOVA was used to test the period effect on CRE and post hoc Bonferroni analysis was performed to test pairwise differences between groups (p < 0.05). RESULTS: Results showed a significantly lower performance in CRE in both sexes. The percentual negative difference was 0.67%, 9.6% and 7% for boys and 5.06%, 14.97% and 9.41% for girls, when comparing the performance in 20-m Shuttle Run test for the first period, respectively. CONCLUSIONS: Results suggest that the physical fitness of Catalan urban adolescents is lower in both sexes when comparing the different analysed periods of time. Therefore, CRE adolescents should be improved in order to help to protect against cardiovascular disease and other health risks in adulthood.

Influence of the Amount of Instability on the Leg Muscle Activity During a Loaded Free Barbell Half-Squat.

This study aimed to understand the acute responses on the muscular activity of primary movers during the execution of a half-squat under different unstable devices. Fourteen male and female high-standard track and field athletes were voluntarily recruited. A repeated measures design was used to establish the differences between muscle activity of the primary movers, the body centre of mass acceleration and the OMNI-Perceived Exertion Scale for Resistance Exercise (OMNI-Res) in a half-squat under four different stability conditions (floor, foam, BOSU-up and BOSU-down). A significant correlation was found between the highest performance limb muscle activity and body centre of mass acceleration for half-squat floor (r = 0.446, p = 0.003), foam (r = 0.322, p = 0.038), BOSU-up (r = 0.500, p = 0.001), and BOSU-down (r = 0.495, p = 0.001) exercises. For the exercise condition, the half-squat BOSU-up and BOSU-down significantly increased the muscle activity compared to half-squat floor (vastus medialis: p = 0.020, d = 0.56; vastus lateralis: p = 0.006, d = 0.75; biceps femoris: p = 0.000-0.006, d = 1.23-1.00) and half-squat foam (vastus medialis: p = 0.005-0.006, d = 0.60-1.00; vastus lateralis: p = 0.014, d = 0.67; biceps femoris: p = 0.002, d = 1.00) activities. This study contributes to improving the understanding of instability training, providing data about the acute muscular responses that an athlete experiences under varied stability conditions. The perturbation offered by the two BOSU conditions was revealed as the most demanding for the sample of athletes, followed by foam and floor executions.

Effects of Wearing a Jaw-repositioning Intra-oral Device in Synchronized Swimming Athletes.

The effects of wearing an intra-oral device on several ventilatory and fatigue markers have been reported for a variety of sports. The quality of the figures performed in synchronized swimming is directly affected by fatigue, and can be monitored during training sessions (TS). The aim of the study was to investigate the acute effects of wearing customized intra-oral devices on heart rate variability, rating of perceived exertion, blood lactate accumulation, and salivary cortisol production during a competitive training session. Twelve highly trained elite female athletes (age: 21.0±3.6 years) participated in the study. Fatigue markers were assessed at the beginning and at the end of the 3rd and 5th afternoon TS for that week, once with and once without an intra-oral device, in random order. Salivary cortisol levels were higher in relation to the baseline in the intra-oral device condition (P<0.05) but not in athletes without an intra-oral device. No differences between conditions were found in rating of perceived exertion (P=0.465) and blood lactate (P=0.711). No time or condition interactions or main effects were shown for heart rate variability. Thus, there is no evidence that wearing a low-arch intra-oral device is a good recommendation for high-standard athletes performing long and stressful routines.

Inter-limb asymmetries are associated with decrements in physical performance in youth elite team sports athletes.

Actually, there is scarce literature looking for the relationship between inter-limb asymmetries and performance in youth elite team sports. The main purpose of this cross-sectional study was to examine the relationships between inter-limb asymmetries and physical performance in youth elite team-sports players. A secondary objective was to evaluate the presence of between-sexes differences in inter-limb asymmetries in elite youth team sports players. Eighty-one young elite team-sports athletes (age: u-14 to u-18) performed the star excursion balance test in the anterior direction (SEBT ANT), a single leg vertical countermovement jump test (SLCMJ), the one leg hop test for distance (OLHT), a 30 m sprint test, and the V-cut test. Inter-limb asymmetries were calculated for SEBT ANT, SLCMJ and OLHT. Pearson r was used to analyse the relationships between inter-limb asymmetries and physical performance. Results showed significant (p < 0.05) but small (r = 0.26) relationships between SLCMJ asymmetries and 30 m sprint time for the total group. Significant negative correlations with small to moderate magnitude of correlation were also found between SLCMJ asymmetries and SLCMJ performance on the lowest performing limb for the total group (p < 0.05; r = -0.26), males (p < 0.01; r = -0.48) and females (p < 0.05; r = -0.30). Moreover, significant negative correlations with moderate and large magnitude were also present between OLHT asymmetries and OLHT performance on the lowest performing limb for the total group (p < 0.01; r = -0.44), males (p < 0.01; r = -0.56) and females (p < 0.01; r = -0.64). No correlations were observed between asymmetries and either the V-cut test or SEBT ANT performance. No correlation were observed between SEBT ANT asymmetries and physical performance. In addition, when comparing asymmetry values between sexes there were no significant differences in vertical (p = 0.06) and horizontal (p = 0.61) jumping tests. However, there were significant differences in asymmetry between sexes in the ANT SEBT (p = 0.04). In conclusion, the current study indicated that jumping asymmetries were associated with decrements in sprint speed and jumping performance. Therefore, assessing inter-limb asymmetries would be recommended to improve training interventions for youth elite team-sports athletes.

Comparison of home advantage in men's and women's Portuguese roller hockey league / Comparación de la ventaja de jugar en casa según género en la liga portuguesa de hockey sobre patines / Comparação da vantagem de jogar em casa dependendo do género na liga portuguesa de hóquei patins

The purpose of this study was to quantify the home advantage in both men's and women's Portuguese professional division roller hockey leagues comparing the results obtained according to the sex of participants. The sample was composed of 2,080 roller hockey games (n = 1,632 in First men's division; and n = 448 in First women's division) between the 2009-2010 and 2016-17 seasons. Goals scored and received were also analysed when teams play at home. The results showed the existence of home advantage in both men's and women's leagues. Home advantage values were higher than 50% in both leagues, with significantly higher values in the male league (60.88% compared to 54.33%). Moreover, the results indicated that teams score a higher percentage of goals when playing at home with non-significant differences between sexes. Regarding the number of goals scored per match, the results showed a significant difference between the male and female divisions, with higher values for men's leagues. The results in relation to sex of participants are consistent with previous studies in other sports like football or water polo. The analysis of the home advantage could be useful to help roller hockey coaches to design alignments for each match and to plan the training loads according to match location

El propósito de este estudio fue cuantificar la ventaja de jugar en casa en las ligas de hockey sobre patines masculina y femenina de la Primera división profesional portuguesa, comparando los resultados obtenidos según el sexo de los participantes. La muestra estuvo compuesta por 2.080 partidos de hockey sobre patines (n = 1.632 en la Primera división masculina y n = 448 en la Primera división femenina) entre las temporadas 2009-2010 y 2016-17. Los goles marcados y recibidos también fueron analizados según la localización del partido. Los resultados mostraron la existencia de la ventaja de jugar en casa tanto en la liga masculina como femenina. Los valores de la ventaja de jugar en casa fueron superiores al 50% en ambas ligas, con valores significativamente más altos en la liga masculina (60,88% comparado con 54,33%). Además, los resultados indicaron que los equipos anotan un mayor porcentaje de goles cuando juegan en casa sin encontrar diferencias significativas entre los sexos. En cuanto al número de goles marcados por partido, los resultados mostraron una diferencia significativa entre ambas divisiones, con valores más altos para las ligas masculinas. Los resultados en relación con el sexo de los participantes están en consonancia con estudios previos realizados en otros deportes colectivos como fútbol o waterpolo. El análisis de la ventaja de jugar en casa podría ser útil para ayudar a los entrenadores de hockey sobre patines a decidir las alineaciones y a planificar las cargas de entrenamiento según la localización del partido

O propósito desse estudo foi quantificar a vantagem de jogar em casa nas ligas masculina e feminina de hóquei sobre patins da Primeira divisão profissional portuguesa, comparando os resultados obtidos dependendo do sexo dos participantes. A amostra foi composta por 2088 partidas de hóquei sobre patins (n= 1.632 na Primeira divisão masculina e n= 448 na Primeira divisão feminina) entre as temporadas 2009-2010 e 2016-17. Os goles marcados e recebidos também foram analisados conforme a localização do partido. Os resultados mostram a existência de vantagem de jogar em casa tanto na liga masculina como na feminina. Os valores da vantagem de jogar em casa são superiores ao 50% em ambas ligas, com valores significativamente maiores na liga masculina (60,88% comparado com os 54,33% da feminina). Por além disso, os resultados indicam que as equipas anotam uma maior percentagem de golos quando jogam em casa, sem encontrar diferenças significativas entre ambos sexos. Em quanto ao número de goles marcados por jogo, os resultados mostram uma diferença significativa entre as divisões masculina e feminina, com valores mais altos na liga masculina. Os resultados em relação ao sexo dos participantes estão em consonância com estudos prévios realizados noutros desportos coletivos como o futebol ou o pólo aquático. A análise da vantagem de jogar em casa poderia ser útil para ajudar aos técnicos de hóquei sobre patins no momento de decidir as alienações e de planificar as cargas dos treinamentos dependendo da localização do jogo

Muscle activation in suspension training: a systematic review.

Suspension training is an adjunct to traditional strength and conditioning. The effect of added instability on muscle activation during traditional exercises is unclear and depends on the exercise and type of instability. The purpose of this review was to compare the activations of different muscles in suspension training exercises and their traditional counterparts. A search of the current literature was performed without language restrictions using the electronic databases PubMed (1969-12 January 2017), SPORTDiscus (1969-12 January 2017) and Scopus (1969-12 January 2017). The inclusion criteria were: (1) descriptive studies; (2) physically active participants; and (3) studies that analysed muscle activation using normalised electromyographic signals during different suspension training exercises. Eighteen studies met the inclusion criteria. For the push-up, inverted row, prone bridge and hamstring curl in suspension, the activation of upper-body and core muscles ranged between moderate (21-40% maximum voluntary isometric contraction (MVIC)) and very high (>60% MVIC). Muscle activation in these same muscle groups was greater with suspension exercises relative to comparable traditional exercises, except for the inverted row. Muscle activation in the upper extremity and core muscles varied greatly amongst studies.

Correlational data concerning body centre of mass acceleration, muscle activity, and forces exerted during a suspended lunge under different stability conditions in high-standard track and field athletes.

This article reports data concerning the body centre of mass acceleration, muscle activity, and forces exerted during a suspended lunge under different stability conditions. Ten high-standard track and field athletes were recruited to perform one set of 5 repetitions of the following exercises: suspended lunge, suspended lunge-Foam (front leg on a foam balance-pad and the rear leg on the suspension cradles), a suspended lunge-BOSU up (dome side up), and a suspended lunge-BOSU down (dome side down). For each exercise trial, the acceleration of the body centre of mass (tri-axial accelerometer BIOPAC), the muscle activity of the front leg (surface electromyography BIOPAC) and the force exerted on the suspension strap (load cell Phidgets) were measured. The data revealed that the intra-reliability of the data range from good (ICC: 0.821) to excellent (ICC: 0.970) in all dependent variables and exercise conditions. Besides, the Pearson correlation between muscle activity and the body centre of mass acceleration showed a significant positive correlation for all the exercises and analysed muscles (range from r = 0.393 to r = 0.826; p < 0.05) with moderate to very large effect, except for the rectus and biceps femoris. Moreover, the force exerted on the suspension strap significantly correlated with the body centre of mass acceleration in all the exercises (range from r = -0.595 to r = -0.797, p < 0.05) with a very large effect, except for the suspension lunge that registered a large effect.

Muscle activity of Bulgarian squat. Effects of additional vibration, suspension and unstable surface.

Practitioners of strength and conditioning are increasingly using vibration and unstable environments to enhance training effects. However, little evidence has been found comparing the use of suspension devices and vibratory platforms used in the Bulgarian squat. The purpose of this cross-sectional study was to examine the effect of suspension devices (TRX®), unstable surfaces (BOSU®), and vibration plates on muscle activity and force during the Bulgarian squat. Twenty physically active male students (age = 24.40 ± 3.63 years) performed a set of five repetitions of Bulgarian squats, suspended lunges, suspended lunges-BOSU, suspended lunges-Vibro30, and suspended lunges-Vibro40 (vibration 30 Hz or 40 Hz and 4 mm of amplitude). A randomized within-subject design was used to compare leg muscle activity, vertical ground reaction forces, and force exerted on the strap across the five exercises. Results showed no significant differences in muscle activity between the Bulgarian squat and suspended lunge (p = 0.109, d = 2.84). However, the suspended lunge significantly decreased muscle activation compared to the suspended lunge-BOSU (p = 0.012, d = 0.47), suspended lunge-Vibro30 (p = 0.001, d = 1.26), and suspended lunge-Vibro40 (p = 0.000, d = 1.51). Likewise, the Bulgarian squat achieved lower activity than the suspended lunge-Vibro40 (p = 0.010, d = 0.96). The force on the strap significantly decreased in the suspended lunge-BOSU compared to the suspended lunge-Vibro30 (p = 0.009, d = 0.56). The suspended lunge achieved higher front leg force production than the Bulgarian squat (p = 0.006, d = 0.48). In conclusion, leaning the rear leg on a suspension device does not provoke an increase in the activation of the front leg during the Bulgarian squat but increases the vertical ground reaction forces. Thus, the use of unstable surfaces or vibration plates for the front leg increased muscular activity when performing a suspended lunge.

Influencia de marcar primero en hockey sobre patines / The influence of scoring first in roller hockey / A influência de marcar primeiro no hóquei em patins

El principal objetivo de este trabajo fue analizar la ventaja de marcar el primer gol del partido en hockey sobre patines y conocer su incidencia en el resultado final. Un objetivo secundario fue valorar si existen diferencias significativas en función de si el equipo que marca primero es el local o el visitante. Para ello se analizaron 240 partidos de la Ok Liga (la máxima categoría deportiva española) y 182 de la Primera División Nacional (segunda categoría más alta) de la temporada 2016-2017, valorando el resultado final de los equipos cuando se adelantaban en el marcador. Los resultados muestran que existe la ventaja de marcar primero tanto en la Ok Liga cómo en la Primera División Nacional con un efecto del 64,14% y 62,91% respectivamente. Asimismo, se obtiene una ventaja de marcar el primer gol significativamente mayor cuando los equipos juegan como locales en la Primera División Nacional y una alta correlación entre el rendimiento final de los equipos (puntos obtenidos en la clasificación) y la ventaja de marcar el primer gol. En consecuencia, se demuestra la importancia que tiene para un equipo dominar dicho aspecto y se sugiere que estos datos pueden ayudar a los equipos técnicos a decidir la estrategia táctica a emplear en cada momento del juego según el resultado del marcador

The main purpose of this study was to analyze the effect of the first goal in roller hockey and to know its impact on the final result. A secondary objective was to assess if there were significant differences when the team that scores first was the local or the visitor. For this purpose, 240 matches of Ok Liga (the highest Spanish division) and 182 of First National Division (the second highest division) were analyzed during the season 2016-2017, assessing the final result of the teams when they scored first. Results showed that the advantage of scoring first exists both in the Ok Liga and in the First National Division with 64.14% and 62.91% respectively. Likewise, the advantage of scoring the first goal when teams play at home is significantly greater for the First National Division teams than Ok Liga teams. In addition, it was obtained a high correlation between the final performance of the teams (points obtained in the classification) and the effect of scoring first. Therefore, it is demonstrated the importance for a team to dominate this aspect and it is suggested that this data can help the coach and staff to decide which strategy to use at each moment of the game according to the result

O objetivo principal deste trabalho foi analisar a vantagem de marcar o primeiro gol do jogo em hóquei em patins e conhecer o seu impacto no resultado final. Um objetivo secundário foi avaliar se existem diferenças significativas dependendo se a equipa que pontua primeiro é a local ou a visitante. Para este fim, foram analisados 240 jogos da Ok Liga (a mais alta categoria desportiva espanhola) e 182 da Primeira Divisão Nacional (segunda maior categoria) da temporada 2016-2017, avaliando o resultado final das equipas quando estavam à frente no placar. Os resultados mostram que há a vantagem de marcar primeiro tanto na Ok Liga quanto na Primeira Divisão Nacional, com um efeito de 64.14% e 62.91%, respetivamente. Da mesma forma, obtém-se uma vantagem de marcar o primeiro gol significativamente maior quando as equipas jogam em casa na Primeira Divisão Nacional e uma alta correlação entre o desempenho final das equipas (pontos obtidos na classificação) e a vantagem de marcar o primeiro gol. Consequentemente, demonstra-se a importância que tem para uma equipa a dominar esse aspecto e sugere-se que esses dados possam ajudar às equipas técnicas a decidirem a estratégia tática a ser utilizada em cada momento do jogo de acordo com o resultado do placar

Effects of jaw clenching wearing customized mouthguards on agility, power and vertical jump in male high-standard basketball players.

BACKGROUND/OBJECTIVE: Basketball players commonly use mouthguards for protecting their mouths from collisions with other players. Besides, literature reports that specific types of mouthguards may become an ergogenic device that facilitates a powerful jaw clenching, and a subsequent concurrent activation potentiation through this remote voluntary contraction of the mandible muscles. METHODS: A randomized within-subjects design was used to study the effects of this mechanism on muscular performance (vertical jump, agility, bench press power and leg press power) into two different conditions (mouthguard and no mouthguard) in high-standard basketball players (n = 13). A mean differences analysis and a responder analysis were conducted. RESULTS: Significant improvements were found (p < 0.05) in all vertical jump protocols using the mouthguard when compared to the no mouthguard conditions. However, no significant differences were found between the two conditions in agility and power (except in one load of bench press). Nevertheless, p-values were closer to statistical significance when analyzing the total time for the agility T-Test than when the first split time was under consideration (p = 0.111 and p = 0.944, respectively). CONCLUSION: This study demonstrated that the use of custom-made, bite-aligning mouthguard had an ergogenic effect on jump outcomes and inconclusive results in agility T-Test in professional basketball players. From the results obtained in the present study, the use of this type of mouthguards seems to be more justified in power actions on the court than in the strength and conditioning sessions at the gym in well-trained players.