Effect of 4 weeks of plyometric training in the pre-competitive period on volleyball athletes' performance.

We aimed to evaluate the effect of 4 weeks of plyometric training (PT), performed in the pre-competitive period, on the vertical jump performance of professional volleyball athletes. We recruited 17 professional female volleyball players (age: 19 ± 3 years; weight: 67.2 ± 5.50 kg; height: 1.81 ± 0.22 m; body fat: 14.4 ± 2.12%; squat 1RM test: 75.5 ± 7.82 kg; training time experience: 6.2 ± 3.4 years) to participate in four weeks of training and assessments. They were divided into an experimental group (EG = 9) and a control group (CG = 8). Both groups were submitted to friendly matches, technical, tactical and resistance training (4 weeks/˜9 sessions per week), and internal load monitoring was carried out. The EG performed PT twice a week. At the beginning and end of the four weeks, jump tests were performed. The main findings are: 1) PT when incorporated into the pre-competitive period can induce greater improvements in jumping performance (EG = 28.93 ± 3.24 cm to 31.67 ± 3.39 cm; CG = 27.91 ± 4.64 cm to 28.97 ± 4.58 cm; when comparing the percentage delta, we found a difference between groups with ES of 1.04 and P = 0.02); 2) this result is observed when the training load is similar between groups and increases over the weeks, respecting the linear progression principle. Therefore, including plyometric training in the preparatory period for volleyball, with low monotony and training strain increment, is an effective strategy for further CMJ performance improvement.

Training-intensity Distribution on Middle- and Long-distance Runners: A Systematic Review.

Training-intensity distribution (TID) is considered the key factor to optimize performance in endurance sports. This systematic review aimed to: I) characterize the TID typically used by middle-and long-distance runners; II) compare the effect of different types of TID on endurance performance and its physiological determinants; III) determine the extent to which different TID quantification methods can calculate same TID outcomes from a given training program. The keywords and search strategy identified 20 articles in the research databases. These articles demonstrated differences in the quantification of the different training-intensity zones among quantification methods (i. e. session-rating of perceived exertion, heart rate, blood lactate, race pace, and running speed). The studies that used greater volumes of low-intensity training such as those characterized by pyramidal and polarized TID approaches, reported greater improvements in endurance performance than those which used a threshold TID. Thus, it seems that the combination of high-volume at low-intensity (≥ 70% of overall training volume) and low-volume at threshold and high-intensity interval training (≤ 30%) is necessary to optimize endurance training adaptations in middle-and long-distance runners. Moreover, monitoring training via multiple mechanisms that systematically encompasses objective and subjective TID quantification methods can help coaches/researches to make better decisions.

Anaerobic Threshold Prediction Using the OMNI-Walk/Run Scale in Long-Distance Runners: A Preliminary Study.

PURPOSE: To identify the anaerobic threshold through the lactate threshold determined by Dmax and rating of perceived exertion (RPE) threshold by Dmax and to evaluate the agreement and correlation between lactate threshold determined by Dmax and RPE threshold by Dmax during an incremental test performed on the treadmill in long-distance runners. METHODS: A total of 16 long-distance runners volunteered to participate in the study. Participants performed 2 treadmill incremental tests for the collection of blood lactate concentrations and RPE separated by a 48-hour interval. The incremental test started at 8 km·h-1, increasing by 1.2 km·h-1 every third minute until exhaustion. During each stage of the incremental test, there were pauses of 30 seconds for the collection of blood lactate concentration and RPE. RESULTS: No significant difference was found between methods lactate threshold determined by Dmax and RPE threshold by Dmax methods (P = .664). In addition, a strong correlation (r = .91) and agreement through Bland-Altman plot analysis were found. CONCLUSIONS: The study demonstrated that it is possible to predict anaerobic threshold from the OMNI-walk/run scale curve through a single incremental test on the treadmill. However, further studies are needed to evaluate the reproducibility and objectivity of the OMNI-walk/run scale for anaerobic threshold determination.

Different Shoulder Exercises Affect the Activation of Deltoid Portions in Resistance-Trained Individuals.

The aims of this study were to compare muscle activity of the anterior deltoid, medial deltoid, and posterior deltoid in the bench press, dumbbell fly, shoulder press, and lateral raise exercises. Thirteen men experienced in strength training volunteered for the study. Muscle activation was recorded during maximum isometric voluntary contraction (MVIC) for data normalization, and during one set of 12 repetitions with the load of 60% 1RM in all exercises proposed. One-way repeated-measures ANOVA with Bonferroni's posthoc was applied using a 5% significance level. For anterior deltoid, the shoulder press (33.3% MVIC) presented a significantly higher level of activation when compared to other exercises. Also, no significant difference was found between the bench press (21.4% MVIC), lateral raise (21.2% MVIC), and dumbbell fly (18.8% MVIC). For the medial deltoid, the lateral raise (30.3% MVIC) and shoulder press (27.9% MVIC) presented a significantly higher level of activity than the bench press (5% MVIC) and dumbbell fly (3.4% MVIC). Besides, no significant difference was found between the bench press and the dumbbell fly. For the posterior deltoid, the lateral raise (24% MVIC) presented a significantly higher level of activation when compared to other exercises. For the posterior deltoid portion, the shoulder press (11.4% MVIC) was significantly more active than the bench press (3.5% MVIC) and dumbbell fly (2.5% MVIC). Moreover, no significant difference was found between the bench press and the dumbbell fly. In conclusion, the shoulder press and lateral raise exercises showed a higher level of muscle activation in the anterior deltoid and medial deltoid when compared to the bench press and dumbbell fly exercises.

Comparison of methods to determine the lactate threshold during leg press exercise in long-distance runners

Abstract Aims: To determine lactate threshold (LT) by three different methods (visual inspection, algorithmic adjustment, and Dmax) during an incremental protocol performed in the leg press 45° and to evaluate correlation and agreement among these different methods. Methods: Twenty male long-distance runners participated in this study. Firstly, participants performed the dynamic force tests in one-repetition maximum (1RM). In the next session, completed an incremental protocol consisted of progressive stages of 1 min or 20 repetitions with increments of 10, 20, 25, 30, 35, and 40% 1RM. From 40% 1RM, increments corresponding to 10% 1RM were performed until a load in which the participants could not complete the 20 repetitions. A rest interval of 2 min was observed between each stage for blood collection and adjustment of the workloads for the next stage. Results: Our results showed no significant difference in relative load (% 1RM), good correlations, and high intraclass correlation coefficients (ICC) between algorithmic adjustment and Dmax (p = 0.680, r = 0.92; ICC = 0.959), algorithmic adjustment and visual inspection (p = 0.266, r = 0.91; ICC = 0.948), and Dmax and visual inspection (p = 1.000, r = 0.88; ICC = 0.940). In addition, the Bland-Altman plot and linear regression showed agreement between algorithmic adjustment and Dmax (r2 = 0.855), algorithmic adjustment and visual inspection (r2 = 0.834), and Dmax and visual inspection (r2 = 0.781). Conclusion: The good correlation and high agreement among three methods suggest their applicability to determine LT during an incremental protocol performed in the leg press 45°. However, the best agreement found between mathematical methods suggests better accuracy.

Métodos de determinación de la velocidad crítica en corredores / Methods for determining critical speed corridors

RESUMEN El creciente interés en la corrida como ejercicio, y particularmente como deporte de competición, demanda estudiar la eficiencia metabólica que presentan los corredores. La estimación de la velocidad crítica (VC) ha sido utilizada en diferentes estudios por ser de fácil aplicabilidad para determinar el umbral anaeróbico del corredor, considerando la intensidad del esfuerzo y el tiempo en que se ejecuta. El objetivo del presente trabajo fue identificar y comparar la eficiencia de los métodos que están siendo utilizados en la actualidad para la estimación de la VC en corredores. Se realizó una revisión bibliográfica de artículos científicos publicados durante el periodo 2011 a 2016. El análisis de literatura mostró que en la estimación de la VC se emplean diferentes estrategias: test máximos y submáximos, continuos e intermitentes, en pista de atle tismo, trotadora y asfalto; con distintos grupos de corredores. La velocidad crítica permitió establecer eficazmente el umbral anaeróbico de las personas que practican la corrida, independientemente del grupo de individuos analizados, de forma simple, menos costosa, e igual de confiable que otros métodos de estimación del umbral anaeróbico más sofisticados, que requieren pruebas de laboratorio.

ABSTRACT The growing interest in running as an exercise, and particularly as a sport of competition, demands the study of runner's metabolic efficiency. The estimate of the critical velocity (CV) has been used in different studies to since it is a method of simple applicability to determine the anaerobic threshold of runners, taking into consideration the intensity of effort and the execution time. The objective of the present work was to identify and compare the efficiency of methods that are currently being used for the estimation of runner's CV. A bibliographic review of scientific articles published during the period 2011 to 2016 was carried out. The analysis of the literature showed the estimation of CV is determined by different strategies such as: maximal and submaximal tests, continuous and intermittent, in athletics track, tradmill and asphalt; with different groups of runners. The determination of critical velocity enabled an efficient establishment of the anaerobic threshold of runners, regardless of the group of individuals analyzed in a simpler, less costly, and equally reliable as other more sophisticated methods of anaerobic threshold estimation that require laboratory tests.