Quantifying Neuromuscular Fatigue Induced by an Intense Training Session in Rugby Sevens

2017 ◽  
Vol 12 (2) ◽  
pp. 218-223 ◽  
Author(s):  
Bruno Marrier ◽  
Yann Le Meur ◽  
Julien Robineau ◽  
Mathieu Lacome ◽  
Anthony Couderc ◽  
...  

Purpose:To compare the sensitivity of a sprint vs a countermovement-jump (CMJ) test after an intense training session in international rugby sevens players, as well as analyze the effects of fatigue on sprint acceleration.Methods:Thirteen international rugby sevens players completed two 30-m sprints and a set of 4 repetitions of CMJ before and after a highly demanding rugby sevens training session.Results:Change in CMJ height was unclear (–3.6%; ±90% confidence limits 11.9%. Chances of a true positive/trivial/negative change: 24/10/66%), while a very likely small increase in 30-m sprint time was observed (1.0%; ±0.7%, 96/3/1%). A very likely small decrease in the maximum horizontal theoretical velocity (V0) (–2.4; ±1.8%, 1/4/95%) was observed. A very large correlation (r = –.79 ± .23) between the variations of V0 and 30-m-sprint performance was also observed. Changes in 30-m sprint time were negatively and very largely correlated with the distance covered above the maximal aerobic speed (r = –.71 ± .32).Conclusions:The CMJ test appears to be less sensitive than the sprint test, which casts doubts on the usefulness of a vertical-jump test in sports such as rugby that mainly involve horizontal motions. The decline in sprint performance relates more to a decrease in velocity than in force capability and is correlated with the distance covered at high intensity.

2020 ◽  
Vol 18 (3) ◽  
pp. 37-41
Author(s):  
Caique Lopes Müeller ◽  
Pedro Sotero da Cunha Neto ◽  
Eloir Junior da Silva Dos Santos ◽  
Alexandre Oliveira ◽  
Rosimeide Francisco dos Santos Legnani ◽  
...  

OBJETIVO: Determinar a correlação entre a percepção subjetiva do esforço (PSE) e a fadiga neuromuscular dos membros inferiores por meio de saltos mensurados no pré e pós treino em atletas de futebol.MÉTODOS: Quatorze atletas de futebol (sub 17) foram monitorados ao longo de quatro sessões de treinamento. Com as seguintes características: estatura (173±6,81cm), peso (64,43±5,80kg) e percentual de gordura (14,74±3,11). A PSE foi monitorada por meio do aplicativo e-trimp, 15 minutos após o final de cada sessão de treinamento. Os saltos foram avaliados por meio da plataforma de salto Jump System Pro, 10 minutos, antes e depois das sessões de treinamento. Os dados foram analisados no programa estatístico SPSS por meio da estatística descritiva e correlação de Spearman.RESULTADOS: A correlação entre a PSE e a diferença da potência relativa do salto vertical (pré/pós treino) foi fraca para todas as sessões. As sessões 1 e 4 apresentaram correlação negativa (r=-0,184, p=0,530; r=-0,159, p=0,587). As sessões 2 e 3 apresentaram correlação positiva (r=0,010, p=0,973; r=0,373, p=0,188), respectivamente.CONCLUSÃO: Não foram observadas correlações estatisticamente significativas entre a PSE e a potência relativa de salto nos atletas avaliados.ABSTRACT. The correlation between the rating of perceived exertion and neuromuscular fatigue on the lower body in soccer athletes.OBJECTIVE: Define the correlation between the rating of perceived exertion (RPE) and the power of the lower limbs before and after training in soccer athletes.METHODS: Were monitored 14 soccer athletes (under 17 years old) over four training sessions. With the following characteristics: height (173±6.81cm), weight (64.43±5.80kg) and fat percentage (14.74±3.11). RPE was monitored through the e-trimp app, 15 minutes after the end of each training session. Jumps were evaluated through the Jump System Pro jumping platform, 10 minutes before and after the training sessions. Data was analyzed in the SPSS statistical program using descriptive statistics and Spearman correlation.RESULTS: The correlation between the RPE and the difference of the relative power of the vertical jump test (pre/post training) was weak for all the sessions. Sessions 1 and 4 presented a negative correlation (r=-0.184, p=0.530; r=-0.159, p=0.587). Sessions 2 and 3 showed a positive correlation (r=0.010, p=0.973; r=0.373, p=0.188), respectively.CONCLUSION: There were no statistically significant correlations between the RPE and the relative jumping power in the evaluated athletes.


2011 ◽  
Vol 29 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Mário Marques ◽  
Helena Gil ◽  
Rui Ramos ◽  
Aldo Costa ◽  
Daniel Marinho

Relationships Between Vertical Jump Strength Metrics and 5 Meters Sprint TimeThe aim of this study was to examine the relationship between short sprint time (5 m) and strength metrics of the countermovement jump (CMJ) using a linear transducer in a group of trained athletes. Twenty-five male, trained subjects volunteered to participate in the study. Each volunteer performed 3 maximal CMJ trials on a Smith machine. Peak instantaneous power was calculated by the product of velocity taken with the linear transducer. For sprint testing, each subject performed three maximum 5 m sprints. Only the best attempt was considered in both tests. Pearson product-moment correlation coefficients between 5 m sprint performance and strength metrics of the CMJ were generally positive and of clear moderate to strong magnitude (r = -0.664 to -0.801). More noticeable was the significant predictive value of bar displacement time (r= ~0.70) to sprint performance. Nevertheless, a non-significant predictive value of peak bar velocity and rate of force development measurements was found. These results underline the important relationship between 5 m sprint and maximal lower body strength, as assessed by the force, power and bar velocity displacement. It is suggested that sprinting time performance would benefit from training regimens aimed to improve these performance qualities.


2021 ◽  
Author(s):  
Matheus Dantas ◽  
Rui Barbosa Neto ◽  
Natália Mendes Guardieiro ◽  
Ana Lucia de Sá Pinto ◽  
Bruno Gualano ◽  
...  

During the COVID-19 pandemic, the necessity of using face masks during sports is likely balanced by coaches and athletes between the risk of infection and their impact on exercise performance. To inform this decision, we aimed to test the effects of wearing a cloth face mask on exercise performance and subjective responses during training of track and field athletes. Participants (n=10) performed two training sessions with and without a 3-layered cloth mask in a randomized, counterbalanced, crossover design. The training session was designed to simulate the specific demands of the sport that the athletes practiced. The sprint protocol consisted of performing five maximal 30 m sprints, with a passive 4-min interval between runs. Performance variables (sprint time, acceleration) were calculated using the sprint time data. Jump performance was assessed pre- and post-sprints using a countermovement vertical jump. Throughout the training session, ratings of perceived exertion (RPE) and affect were collected. There was no evidence of condition x time interactions for sprint time (P=0.21) or acceleration (P=0.47). There was weak evidence of an effect of condition (P=0.05) on RPE, though no evidence of a condition x time interaction (P=0.35). There was moderate evidence of a condition x time interaction (P=0.02) for affect, with lower ratings following sprints 3, 4 and 5 when using the mask. These findings suggest that wearing a mask may negatively impact subjective feelings of training without necessarily harming sprint performance. During an unmitigated epidemic such as in Brazil, the protection against SARS-CoV-2 infection associated with wearing a face mask appears to outweigh the increased discomfort and perception of effort related to this safety tool.


2019 ◽  
Vol 1 (1) ◽  
pp. 4-10
Author(s):  
Jair Burboa G ◽  
Mauricio Inostroza M ◽  
Matías Bahamondes F ◽  
Paloma Lillo U ◽  
Jaime Hinzpeter C

An anterior cruciate ligament (ACL) injury is an important cause of rest in athletes. In most cases, ACL injuries do not require external contact and they are associated with biomechanical risk factors that increase ACL tension. The increase of the hip flexion angle (HF) is included within these. The ACL requires cooperation of the periarticular musculature of the knee, muscle groups, hip stabilizers and CORE muscles; consequently, fatigue caused by exercise would alter the balance and put this ligament at risk. The objective of the study is to determine the angular behavior for HF before and after a physical load (a standardized training) in children between 11 and 12 years old. A non-randomized clinical study was carried out. The sample consisted of 50 soccer school students born between 11 and 12 years old. The angular behavior of HF was compared before and after performing a training session. The angular behavior was measured through the Drop Jump test (DJ), with data obtained by inertial sensors. After the exercise, there was a significant increase in HF. It was concluded that the angular behavior of HF increases significantly in both extremities after training and that preventive measures must be applied for neuromuscular control of the hip.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jader Sant' Ana ◽  
Raphael Luiz Sakugawa ◽  
Fernando Diefenthaeler

This study aimed to verify the effect of a pace training session at an intensity corresponding to the kick frequency at the anaerobic threshold (KFAT) on the internal load response and motor response performance of the roundhouse kick. Twelve black belt taekwondo athletes underwent two evaluation sessions: (1) performed the progressive specific test for taekwondo (PSTT) to identify the heart rate deflection point (HRDP) and the KFAT; (2) performed three 2-min rounds with a 1-min interval. Heart rate (HR) throughout each round and motor response performance before and after sessions were measured. The Student's T-test or Wilcoxon test was used, and p < 0.05 was adopted. During round 1, a lower internal load was observed (167 ± 10 bpm) compared with HRDP (179 ± 8 bpm; p = 0.035). During rounds 2 (178 ± 10 bpm; p = 0.745) and 3 (179 ± 8 bpm; p = 1), no differences were observed for an internal load and HRDP. Motor response performance showed no differences. However, a potentiation in the post countermovement jump test compared with rounds 1 (p = 0.012) and 2 (p = 0.028) was observed. The internal load (HR) observed at the intensity corresponding to KFAT can be considered in the prescription of training when the aim is to control the internal load responses without inducing fatigue.


2016 ◽  
Vol 17 (3) ◽  
Author(s):  
Daniele Detanico ◽  
Nicole Vitório Librizzi ◽  
Marina Saldanha Da Silva Athayde

AbstractThe study aimed to verify the effects of a simulated taekwondo tournament on vertical jump as well as technical and tactical performance in athletes of the Brazilian national team.The study involved 10 male Songahm taekwondo athletes. They took part in a simulated tournament in sparring modality, comprising four 2-minute fights with different opponents. Before and after each fight, the athletes performed the Sargent Jump Test and were asked to indicate the rate of the perceived exertion (RPE). In addition, the fights were recorded and some technical and tactical variables were analysed, namely the number of kicks, effectiveness, and technical variety. The analysis of variance for repeated measures with the Bonferroni post hoc test was used, with the significance level set atNo significant differences in the jump height were observed throughout the fights (The simulated taekwondo tournament had no effect on vertical jump or technical and tactical performance throughout the fights. The athletes were able to recover the effort perception before each new fight.


2021 ◽  
Vol 12 ◽  
Author(s):  
Aleksander Matusiński ◽  
Przemysław Pietraszewski ◽  
Michał Krzysztofik ◽  
Artur Gołaś

Considering the effectiveness of resisted sprint training, and the acute enhancement of sprinting performance through locomotor post-activation performance enhancement, the main objective of the research was to determine the acute effects of resisted activation with loads of 5, 10, and 15% body mass on sprint and flying start sprint performance in elite female sprinters using resisted drag technology system. Ten elite female sprinters (age: 23.2 ± 5.4 years, body mass: 54.2 ± 6.1 kg, height: 167.4 ± 7.3 cm, personal best for 100 m: 12.05 ± 0.56 s, and for 400 m: 53.17 ± 2.76 s) performed two unresisted 20-m sprints (from a crouched and flying start) before and after a single resisted sprint loaded with 5, 10, or 15% body mass to verify the effectiveness of the activation stimulus. Compared with pre-activation, Friedman tests showed that peak velocity increased by 1.6 ± 2.2% [effect size (ES) = 0.66], 2.3 ± 1.5% (ES = 1.33), and 0.2 ± 1% (ES = 0.09), as well as peak force by 2.8 ± 2.1% (ES = 0.49), 3.5 ± 2.3% (ES = 1), and 0.5 ± 2.4% (ES = 0.14), concomitant with a significant decreased in sprint time by −0.5 ± 1.2% (ES = −0.07), −2.5 ± 1.3% (ES = −0.64), and −1 ± 1.4% (ES = −0.36) for the 5, 10, and 15% body mass post-activation, respectively (p < 0.001; for all). Furthermore, the ANOVA showed that peak power increased by 2.9 ± 2.3% (ES = 0.61), 3.8 ± 2.2% (ES = 1.05), and 2 ± 7.1% (ES = 0.22) for the 5, 10, and 15% body mass resisted-conditioning activity, respectively, with no difference between the three conditions (p = 0.003 main effect time, no interaction). Moreover, compared with the 5 and 15% body mass trials [−1.5 ± 2% (ES = −0.44), −0.8 ± 0.8% (ES = −0.44), respectively], the ANOVA showed that flying start sprint time significantly decreased by −4.3 ± 1.1% (ES = −1.25) (p < 0.001, interaction effect) after a 10% body mass resisted-conditioning activity. The results of this study indicated that resisted sprints acutely enhance sprint performance; however, their effectiveness depends on the applied load. A single resisted sprint using 10% body mass is effective at inducing a potentiating effect on subsequent 20-m flying start sprint performance in elite female sprinters. Therefore, keeping in mind the optimal load, it is recommended to perform resisted sprints as a conditioning activation when seeking to acutely enhance 20-m flying start sprint performance in these athletes.


Author(s):  
Nuno Batalha ◽  
Jose A. Parraca ◽  
Daniel A. Marinho ◽  
Ana Conceição ◽  
Hugo Louro ◽  
...  

The purpose of this study was to analyze the acute effects of a standardized water training session on the shoulder rotators strength and balance in age group swimmers, in order to understand whether a muscle-strengthening workout immediately after the water training is appropriate. A repeated measures design was implemented with two measurements performed before and after a standardized swim session. 127 participants were assembled in male (n = 72; age: 16.28 ± 1.55 years, height: 174.15 ± 7.89 cm, weight: 63.97 ± 6.51 kg) and female (n = 55; age: 15.29 ± 1.28 years, height: 163.03 ± 7.19 cm, weight: 52.72 ± 5.48 kg) cohorts. The isometric torque of the shoulder internal (IR) and external (ER) rotators, as well as the ER/IR ratios, were assessed using a hand-held dynamometer. Paired sample t-tests and effect sizes (Cohen’s d) were used (p ≤ 0.05). No significant differences were found on the shoulder rotators strength or balance in males after training. Females exhibited unchanged strength values after practice, but there was a considerable decrease in the shoulder rotators balance of the non-dominant limb (p < 0.01 d = 0.366). This indicates that a single practice seems not to affect the shoulders strength and balance of adolescent swimmers, but this can be a gender specific phenomenon. While muscle-strengthening workout after the water session may be appropriate for males, it can be questionable regarding females. Swimming coaches should regularly assess shoulder strength levels in order to individually identify swimmers who may or may not be able to practice muscle strengthening after the water training.


Author(s):  
Nafih Cherappurath ◽  
Masilamani Elayaraja ◽  
Dilshith A. Kabeer ◽  
Amila Anjum ◽  
Paris Vogazianos ◽  
...  

AbstractTennis is one of the most popular and widely played sports enjoyed by players of different age groups and genders as a profession as well as a mode of recreation. A novel method, PETTLEP imagery combines both conventional and non-conventional style of training of an athlete and improves one’s performance. This study aimed to analyze the tennis service performance of junior tennis players based on PETTLEP imagery training. Forty-four junior male tennis players (Mage=13.22 years, SD=0.42) were selected for the study. The investigator handed over the MIQ-R questionnaire to all the participants in which they scored 16 and above points as per previous research. The participants were equally divided (n=11) into three experimental groups (E1, E2, and E3) and a control group. The service performance outcomes of all the players were compared before and after a training session. The three experimental groups were assigned with service-specific training, service-specific training combined with PETTLEP imagery training, and PETTLEP imagery training alone, respectively, for three days per week for 12 weeks. They were tested on their service accuracy based on the International tennis number (ITN) manual on-court assessment test. The data were assessed for normality and analyzed using non-parametric methods to reveal main effects (each training method alone) as well as to calculate the combined effect of PETTLEP and service-specific training. Certain significant improvements in tennis service were observed with service-specific training alone. Though it marginally outperformed the PETTLEP imagery method, the most improved services were observed with both PETTLEP and service-specific training utilized together. This implies an additive effect when both methods are used together.


2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Kaoru Tachiiri

AbstractThe transient climate response to cumulative carbon emissions (TCRE) is a key metric in estimating the remaining carbon budget for given temperature targets. However, the TCRE has a small scenario dependence that can be non-negligible for stringent temperature targets. To investigate the parametric correlations and scenario dependence of the TCRE, the present study uses a 512-member ensemble of an Earth system model of intermediate complexity (EMIC) perturbing 11 physical and biogeochemical parameters under scenarios with steady increases of 0.25%, 0.5%, 1%, 2%, or 4% per annum (ppa) in the atmospheric CO2 concentration (pCO2), or an initial increase of 1% followed by an annual decrease of 1% thereafter. Although a small difference of 5% (on average) in the TCRE is observed between the 1-ppa and 0.5-ppa scenarios, a significant scenario dependence is found for the other scenarios, with a tendency toward large values in gradual or decline-after-a-peak scenarios and small values in rapidly increasing scenarios. For all scenarios, correlation analysis indicates a remarkably large correlation between the equilibrium climate sensitivity (ECS) and the relative change in the TCRE, which is attributed to the longer response time of the high ECS model. However, the correlations of the ECS with the TCRE and its scenario dependence for scenarios with large pCO2 increase rates are slightly smaller, and those of biogeochemical parameters such as plant respiration and the overall pCO2–carbon cycle feedback are larger, than in scenarios with gradual increases. The ratio of the TCREs under the overshooting (i.e., 1-ppa decrease after a 1-ppa increase) and 1-ppa increase only scenarios had a clear positive relation with zero-emission commitments. Considering the scenario dependence of the TCRE, the remaining carbon budget for the 1.5 °C target could be reduced by 17 or 22% (before and after considering the unrepresented Earth system feedback) for the most extreme case (i.e., the 67th percentile when using the 0.25-ppa scenario as compared to the 1-ppa increase scenario). A single ensemble EMIC is also used to indicate that, at least for high ECS (high percentile) cases, the scenario dependence of the TCRE should be considered when estimating the remaining carbon budget.


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