Using Bar Velocity to Predict Maximum Dynamic Strength in the Half-Squat Exercise

2016 ◽  
Vol 11 (5) ◽  
pp. 697-700 ◽  
Author(s):  
Irineu Loturco ◽  
Lucas A. Pereira ◽  
Cesar C. Cal Abad ◽  
Saulo Gil ◽  
Katia Kitamura ◽  
...  

Purpose:To determine whether athletes from different sport disciplines present similar mean propulsive velocity (MPV) in the half-squat (HS) during submaximal and maximal tests, enabling prediction of 1-repetition maximum (1-RM) from MPV at any given submaximal load.Methods:Sixty-four male athletes, comprising American football, rugby, and soccer players; sprinters and jumpers; and combat-sport strikers attended 2 testing sessions separated by 2–4 wk. On the first visit, a standardized 1-RM test was performed. On the second, athletes performed HSs on Smith-machine equipment, using relative percentages of 1-RM to determine the respective MPV of submaximal and maximal loads. Linear regression established the relationship between MPV and percentage of 1-RM.Results:A very strong linear relationship (R2 ≈ .96) was observed between the MPV and the percentages of HS 1-RM, resulting in the following equation: %HS 1-RM = −105.05 × MPV + 131.75. The MPV at HS 1-RM was ~0.3 m/s.Conclusion:This equation can be used to predict HS 1-RM on a Smith machine with a high degree of accuracy.

2021 ◽  
pp. 1-10
Author(s):  
Alex Ojeda-Aravena ◽  
Tomás Herrera-Valenzuela ◽  
Pablo Valdés-Badilla ◽  
Eduardo Baez-San Martín ◽  
José Zapata-Bastías ◽  
...  

BACKGROUND: Repeat high-intensity intermittent efforts is a taekwondo-specific ability but the influence of aerobic capacity and dynamic strength characteristics on this ability has received relatively little attention in the literature. OBJECTIVE: To examine the relationship between specific high-intensity intermittent efforts with aerobic capacity and slow stretch-shortening cycle utilization in taekwondo athletes. METHODS: Nineteen taekwondo male athletes were assessed by squat jump (SJ), countermovement jump (CMJ), 20-meter shuttle run (20MSR), and frequency speed of kick test multiple (FSKTMULT). From the FSKTMULT, total kicks and kick decrement index [KDI] were calculated. Additionally, from both jump tests, the slow stretch-shortening cycle utilization (Slow SSC Utilization) was determined from the eccentric utilization ratio [EUR], pre-stretch augmentation [PSA], and reactive strength index [RSI]. RESULTS: There were positive and significant correlations between total kicks with 20MSR (r= 0.85; p= 0.00) and SJ (r= 0.66; p< 0.05). The multiple regression model demonstrated that total kicks where significantly influenced by 20MSR (R2= 71%; p= 0.00). Additionally, only EUR and RSI explained total kicks performance to a greater proportion (R2= 76%). CONCLUSIONS: The FSKTMULT total kicks performance is positively correlated and influenced by aerobic capacity and slow SSC utilization.


Retos ◽  
2021 ◽  
Vol 41 ◽  
pp. 775-781
Author(s):  
Joel Barrera ◽  
Luis Valenzuela Contreras ◽  
Álvaro Segueida Lorca ◽  
Fernando Maureira ◽  
Eduardo Zurita ◽  
...  

  El objetivo de la presente investigación fue determinar la relación que existe entre el salto contramovimiento y pruebas de velocidad (10-30 m) y agilidad. La muestra estuvo constituida por 169 futbolistas jóvenes entre las categorías sub-13 y sub-19, a los cuales se les aplicó la prueba de salto contramovimiento, velocidad (10-30 m) y agilidad zigzag. Los resultados muestran que la altura del salto contramovimiento presenta una alta correlación negativa con la velocidad 10 m (r=-.693), 30 m (r=-.731) y agilidad (r=-.490). De igual modo, los resultados de la potencia del salto contramovimiento se correlacionan negativamente con la velocidad 10 m (r=-.658), 30 m (r=-.719) y agilidad (r=-.484). Los coeficientes de determinación más altos correspondieron a la altura del salto contramovimiento y velocidad (r2=.534) y la potencia del salto contramovimiento y velocidad (r2=.517). Los resultados obtenidos en el presente estudio sugieren que el salto contramovimiento tiene un alto grado de influencia en el rendimiento en la velocidad (10-30 m), lo cual, parece no estar tan claro en la variable de agilidad. Abstract. The objective of this research was to determine the relationship between countermovement jumping and speed tests (10-30 m) and agility. The sample consisted of 169 young soccer players between the under-13 and under-19 categories, to whom the counter-movement jump test, speed (10-30 m) and zigzag agility were applied. The results show that the height of the countermovement jump shows a high negative correlation with speed 10 m (r = -. 693), 30 m (r = -. 731) and agility (r = -. 490). Similarly, the results of the countermovement jump power are negatively correlated with speed 10 m (r = -. 658), 30 m (r = -. 719) and agility (r = -. 484). The highest coefficients of determination corresponded to the height of the countermovement jump and speed (r2 = .534) and the power of the countermovement jump and speed (r2 = .517). The results obtained in the present study suggest that the countermovement jump has a high degree of influence on speed performance (10-30 m), which seems to be not so clear in the agility variable.


2007 ◽  
Vol 2 (4) ◽  
pp. 414-422 ◽  
Author(s):  
Mário C. Marques ◽  
Roland van den Tillaar ◽  
Jason D. Vescovi ◽  
Juan José González-Badillo

Purpose:The purpose of this study was to examine the relationship between ball-throwing velocity during a 3-step running throw and dynamic strength, power, and bar velocity during a concentric-only bench-press exercise in team-handball players.Methods:Fourteen elite senior male team-handball players volunteered to participate. Each volunteer had power and bar velocity measured during a concentric-only bench-press test with 26, 36, and 46 kg, as well as having 1-repetition-maximum (1-RMBP) strength determined. Ball-throwing velocity was evaluated with a standard 3-step running throw using a radar gun.Results:Ball-throwing velocity was related to the absolute load lifted during the 1-RMBP (r = .637, P = .014), peak power using 36 kg (r = .586, P = .028) and 46 kg (r = .582, P = .029), and peak bar velocity using 26 kg (r = .563, P = .036) and 36 kg (r = .625, P = .017).Conclusions:The results indicate that throwing velocity of elite team-handball players is related to maximal dynamic strength, peak power, and peak bar velocity. Thus, a training regimen designed to improve ball-throwing velocity in elite male team-handball players should include exercises that are aimed at increasing both strength and power in the upper body.


Author(s):  
М.В. ДОВЫДЕНКОВА

Проведена статистическая обработка сформированной базы данных показателей неспецифической резистентности MS «Excel» с целью изучения динамики иммунитета по параметрам бактерицидной, лизоцимной и фагоцитарной активности у крупного рогатого скота черно-пестрой породы разных возрастов. Было установлено, что средние значения показателей лизоцимной и бактерицидной активности у телят в 6 мес были ниже (47,89% и 49,09%, соответственно), чем у животных в 3—4 года (53,75% и 52,81%). Выведено уравнение регрессии, описывающее взаимосвязь между средними показателями фагоцитарной активности и возрастом при высокой степени достоверности (R2=0,90). Изменения лизоцимной и бактерицидной активности в зависимости от возраста были недостоверными (R2=0,58 и R2=0,49, соответственно). Установлена высокая корреляция между бактерицидной и лизоцимной активностью. Отмечена динамика изменения неспецифического иммунитета у коров различных возрастных групп. Создание баз данных и постоянный мониторинг основных показателей естественной резистентности в зависимости от различных факторов (породы, возраста, стадий лактации, кормления, способов содержания), которые влияют на данные показатели, необходимо для оценки физиологического состояния организма животных и их устойчивости к болезням. Statistical processing of the generated MS "Excel" on indicators of non-specific resistance database was carried out with the aim of studying the dynamics of the development of immunity in terms of bactericidal, lysozyme and phagocytic activity in black-and-white cattle of different ages. It was found that the average values of indicators of lysozyme and bactericidal activity in calves at 6 months were lower (47.89% and 49.09%, respectively) than in animals at the age of 3—4 years (53.75% and 52.81%). The equation of regression was derived, it describes the relationship between the average indicators of phagocytic activity and the age with a high degree of reliability (R2=0.90). The changes in lysozyme and bactericidal activity depending on age were dubious (R2=0.58 and R2=0.49, respectively). The high correlation between bactericidal and lysozyme activity was established. It was noticed that the cows of different age groups experienced the dynamics of changes in nonspecific immunity. The creation of databases and constant monitoring of the main indicators of natural resistance, depending on various factors (breed, age, stages of lactation, feeding, methods of keeping) that affect these indicators, is necessary for assessing the physiological state of the animals’ body of and their resistance to diseases.


2019 ◽  
Vol 8 ◽  
pp. 54-56
Author(s):  
Ashmita Dahal Chhetri

Advertisements have been used for many years to influence the buying behaviors of the consumers. Advertisements are helpful in creating the awareness and perception among the customers of a product. This particular research was conducted on the 100 young male and female who use different brands of product to check the influence of advertisement on their buying behavior while creating the awareness and building the perceptions. Correlation, regression and other statistical tools were used to identify the relationship between these variables. The results revealed that the relationship between media and consumer behavior is positive. The adve1tising impact on sales and there is positive and high degree relationship between advertising and consumer behavior. The impact on advertising of a product of electronic media is better than non-electronic media.


1983 ◽  
Vol 245 (3) ◽  
pp. R353-R356
Author(s):  
W. W. Winder ◽  
M. A. Beattie ◽  
E. O. Fuller

The purposes of this study were to determine the effect of different work rates on the rate of liver glycogenolysis and to determine the relationship between liver adenosine 3',5'-cyclic monophosphate (cAMP) levels and the glycogenolytic rate. Rats were run at treadmill speeds ranging from 10 to 34 m/min up a 15% grade for either 30 or 60 min. Both the magnitude of the decrease in liver glycogen and the increase in hepatic cAMP were dependent on the running speed and the duration of running. At the highest work rate a disproportionate acceleration in the liver glycogenolytic rate was observed compared with that at lower work loads, thus resulting in a curvilinear relationship between work rate and liver glycogenolytic rate. A high degree of correlation was found between the liver glycogenolytic rate and hepatic cAMP concentration (r = 0.98). This observation is consistent with the idea that hepatic glycogenolytic rates are determined by cAMP-mediated mechanisms.


2021 ◽  
pp. 194173812199938
Author(s):  
Gabor Schuth ◽  
Gyorgy Szigeti ◽  
Gergely Dobreff ◽  
Peter Revisnyei ◽  
Alija Pasic ◽  
...  

Background: Previous studies have examined the relationship between external training load and creatine kinase (CK) response after soccer matches in adults. This study aimed to build training- and match-specific CK prediction models for elite youth national team soccer players. Hypothesis: Training and match load will have different effects on the CK response of elite youth soccer players, and there will be position-specific differences in the most influential external and internal load parameters on the CK response. Study Design: Prospective cohort study. Level of Evidence: Level 4. Methods: Forty-one U16-U17 youth national team soccer players were measured over an 18-month period. Training and match load were monitored with global positioning system devices. Individual CK values were measured from whole blood every morning in training camps. The dataset consisted of 1563 data points. Clustered prediction models were used to examine the relationship between external/internal load and consecutive CK changes. Clusters were built based on the playing position and activity type. The performance of the linear regression models was described by the R2 and the root-mean-square error (RMSE, U/L for CK values). Results: The prediction models fitted similarly during games and training sessions ( R2 = 0.38-0.88 vs 0.6-0.77), but there were large differences based on playing positions. In contrast, the accuracy of the models was better during training sessions (RMSE = 81-135 vs 79-209 U/L). Position-specific differences were also found in the external and internal load parameters, which best explained the CK changes. Conclusion: The relationship between external/internal load parameters and CK changes are position specific and might depend on the type of session (training or match). Morning CK values also contributed to the next day’s CK values. Clinical Relevance: The relationship between position-specific external/internal load and CK changes can be used to individualize postmatch recovery strategies and weekly training periodization with a view to optimize match performance.


China Report ◽  
2021 ◽  
Vol 57 (1) ◽  
pp. 7-21
Author(s):  
Stephen Nagy

The Indo-Pacific region is now home to at least two competing regionalism road maps, China’s Belt Road Initiative (BRI) and Japan’s Free and Open Indo-Pacific Vision (FOIP). Through comparing their respective development trajectories, this article examines the relationship between these two regionalisation initiatives. Key lines of enquiry include the following: Is the interaction between the BRI and the FOIP Vision reactive, proactive or both? Why has each initiative changed its trajectory? How can we characterise these competing initiatives? This article employs a regionalism matrix analysis that compares two different approaches, integration from a ‘rational-legal perspective’ with an emphasis on broad cooperation and state sovereignty from a ‘process-oriented perspective’ with a focus on exact goals. It finds that the BRI focuses on both a high degree of state sovereignty based on a ‘process-oriented perspective’ and exact cooperation. In contrast, FOIP stresses integration through a ‘rational-legal perspective’, broad cooperation and a shared rules-based order. Furthermore, there is a reactive interplay between these two regionalism frameworks that shapes their orientation and influences their focus.


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