Recovery behavior after matches for returning to training in volleyball athletes

The aim of this research was to evaluate the behavior of vertical jumps performance in professional volleyball athletes during matches and training and their relationships with fatigue and recovery through heart rate variability (HRV), ratings of perceived exertion (RPE) and perceived recovery status (PRS). Nine male professional volleyball athletes participated in the study, with mean age: 25.66 ± 5.7 years, mean body mass: 97.81 ± 8.65 Kg and mean height: 200.94 ± 5.19 cm, with experience in national and international competitions. HRV and PRS were evaluated in the morning of matches and in the presentation for the first day of training after matches. RPE was collected immediately after matches and at the end of training days. Jumps performance was monitored during the matches and during the first days of training. The data was grouped by matches and training sessions. Significance level adopted was α ≤ 0.05. There were no alterations in HRV and PRS evaluated after matches and before training sessions, as well as in RPE after training. Jumps height was greater during the matches (p< 0.013) and there were no differences in the number of jumps. There was a positive correlation between the number of jumps during matches and PRS before matches (r= 0.336, p= 0.015) and a negative correlation between the number of jumps during training and pre-training PRS (r= -0.318, p= 0.002). We conclude that the recovery period proposed by the team proved to be sufficient for the athletes to maintain the same condition for returning to training. This information can assist physical trainers to prescribe training loads for the return to training.

Cross-transfer of motor control in visuomotor tasks. Systematic review

Introduction: The term “cross-education” describes the perfomance improvement, both in motor control and strength, of a limb after training the opposite. Despite its current interest, there is no consensus on many concepts of the transfer of a visuomotor skill. The aim of the present research was to review the current literature on the phenomenon of cross-education in visuomotor skills in order to determine the magnitude of transference and its relationships with the context of the intervention. Results: A literature search was conducted during December 2019 in the databases Pubmed, CINAHL, MEDLINE, Web of Science, SPORTdiscus and Scopus. The descriptors “Motor ability” and “Motor skill” were used, in addition to the keywords “Motor control”, “skill”, “Task”, “cross over effect”, “cross exercise”, “contralateral learning”, “inter limb transfer “,” cross transfer “,” cross education “. After applying the inclusion and exclusion criteria, a total of 19 articles were obtained for analysis. Of these articles, 12 are RCTs, 4 crossover clinical trial, 2 are non-randomized trials and only 1 lacks a control group. Most of the articles consist of a short-term intervention. Only 5 studies are of a duration of between 4 and 6 weeks. Conclusion: the cross-education phenomenon occurs in visuomotor skills. However, the magnitude of transference and its relation to the amount of learning of the trained member seems to be very variable depending on the context of the intervention. Likewise, the scarce consensus and the methodological differences in the studies make it difficult to draw firm conclusions about the effects of the context on the transference.

Morphological evolution of Cuban super heavyweight boxers, 1976-2014

Objective: To evaluate the morphological changes of Cuban super heavyweight boxers, more and less successful, through the period 1976-2014. Material and method: Thirty super heavy boxers, who were members of the Cuban national teams in the period 1976-2014, were compared; The strategy consisted of separating the group in the periods 1976-1989, 1990-1999, 2000-2009 and 2010-2014. Sixteen anthropometric dimensions were recorded (weight, height, sitting height, six skinfold thickness, five girths and two breadths), from which the body composition and the somatotype were obtained. The data were analyzed applying the Analysis of variance (ANOVA). The conglomerate analysis based on the Euclidean distance was used in order to evaluate the correspondence between physical development and sports performance. A discriminant analysis was carried out in order to analyze the contribution of the anthropometrical variables to the variance of different clusters. Results: Most of the anthropometric dimensions and indicators showed significant differences, having an impact on the increase in adiposity, body fat and endomorphy (p <0.05), as well as the decrease in the indicators dependent on height (p <0.05). The analysis by conglomerates, as well as the study of the Migratory Distances of the somatotype, showed that the Olympic medalist boxers differed in terms of the characteristics of body composition and in terms of the intensity of the somatotype changes in the period 1976-2014. Conclusions: The Cuban boxer of the super heavyweight category showed a wide range of morphological demands, but these were framed within the international trends of professional boxers. The morphological attributes of the Olympic medalists differed from each other, and from the rest of the boxers investigated over time. These results provide anthropometric data of high scientific value, both for selection and for medical control of training.

Assessment of professional Argentine football players using the UNCa test

Objective: To evaluate the maximum oxygen consumption (VO2max) and the Maximum Aerobic Speed (MAS) with direct and portable measurement in field, in professional soccer players using the UNCa test. Material and method: 9 professional soccer players (age: 26.8±5.12 years, mass: 78.7±5.8 kg, height: 177.3±5.8 cm), belonging to the first and promotion categories of AFA soccer league, were measured in the field with the UNCa test using direct gas measurement. A subsample of 3 players was also measured on treadmill. On treadmill and in the field, the same Medgraphics® VO2000 gas analyzer was used. Results: In the field, a VO2max of 52.18±5.86 ml/kg/min, and a MAS of 14.8±1.3 km/h were found. Also, a correlation between VO2max and MAS of r = 0.75, and between MAS and the final speed reached (FSR) r=0.91. In the subsample, no differences were found between treadmill and field in VO2max; 46.6±1.4 ml/kg/min and 48.1±2.2 ml/kg/min (p <0.001) respectively. Differences between MAS are shown; 17.0±0.0 km/h for the treadmill and 13.7±1.5 km/h for the field (p <0.001) replicating the protocol. Conclusion: If professional players of the Argentine Football Association (AFA) were measured directly and in the field, applying the UNCa test for the first time. The VO2max and MAS values were slightly lower than those published in the bibliography

Changes in muscle coactivation during running: a comparison between two techniques, forefoot vs rearfoot

Introduction: According to the literature, eccentric exercise has been considered a precursor of neuromuscular changes generated by post-exercise damage, mainly causing an alteration in the muscle cell membrane. Muscle fiber conduction velocity (MFCV) has been one of the physiological variables that have allowed to quantify this alteration. Some investigations have shown a decrease in the MFCV after eccentric exercise protocols; however, few studies have confirmed these findings. This review aimed to describe the recent scientific evidence that reports changes in the MFCV after eccentric exercise protocols. Material and method: From 265 articles, 6 articles were selected from EBSCO and MEDLINE platforms with a temporal filter of 10 years (between 2010 and April 2020), using inclusion/exclusion criteria predetermined. Firstly, the information from eccentric exercise effect on MFCV, and exercise protocols were described. Secondly, the techniques used to record electromyographic signals and some criteria to determine the MFCV were reported. Results: Modifications of MFCV can be observed after eccentric exercise in almost all selected articles. At the same time, a decrease of this variable was observed in four studies, associated with the biceps brachii and two portions of the quadriceps muscles. However, one article describes an increase of the MFCV in the vastus lateralis quadriceps. Conclusion: The articles suggest that eccentric contractions could modify the MFCV behavior of some muscles. However, evidence is still lacking to describe the real cause of these changes.

Endurance exercise: a model of physiological integration

Endurance exercise is a model of physiological integration. There is no other animal activity in which cardiovascular, respiratory, metabolic-endocrine and neuromuscular functions are activated at the same time. Even apparently, silent functions are essential during exercise (digestive, renal). During long-term exercise, the absorption of water and carbohydrates is a determining factor in performance. Kidney function plays a fundamental role in trying to preserve the hydro-electrolyte balance during exercise. In this work we present an integrative physiological perspective during dynamic exercise (mobilization of a large muscle mass with a low to moderate degree of strength development), both from the point of view of health and performance. The response of the heart rate in the first moments of exercise is a good example of the feedforward mechanism. Overall, the nervous system has two control mechanisms: feedforward and feedback. These depend on the central command, a more functional than anatomical entity. The feedforward system allows to immediately start the cardiovascular and respiratory systems. This mechanism is important because it activates the organism to overcome resting state. The feedback system is equally important because it allows the central command to receive the necessary information to “order” the appropriate response according to the intensity of the exercise. The information for retrocontrol comes from various receptors located in: the muscles, the respiratory system and the cardiovascular system. It is complex information that the central nervous system processes with exquisite precision, as can be seen in in endurance exercise.

Analysis and relationship between the anthropometric and somatotype characteristics and cardiovascular capacity in amateur mountain runners: a pilot study

Purpose: The aim of this study was to describe the anthropometrical and cardiovascular characteristics of short course trail runners and analyze the associations, if any, between both anthropometric and cardiovascular features of amateur trail runners. Material and method: Anthropometrical evaluation and an incremental maximum test with 10% of grade on a treadmill were performed on a group of 10 short distance amateur trail runners. Results: Significant negative correlations were found between the body max index (BMI) and the speed at VT1 (Vel VT1) (r = -0,95, p < 0,001), or the time to reach VT1 (r = -0,91, p = 0,002) and between the body fat percentage and the respiratory exchange ratio at VT2 (r = -0,80, p = 0,016) or the time to reach VT2 (r = -0,83, p = 0,01). Calf circumference was also found to be positively associated with oxygen consumption at VT1 (r = 0,74, p = 0,037), at VT2 (r = 0,90, p = 0,002) and with the maximal oxygen uptake (r = 0,85, p = 0,007). Conclusions: Results indicate that both body fat percentage and calf circumference could be related to the performance on an incremental test protocol with inclination in amateur trail runners.

Changes in muscle coactivation during running: a comparison between two techniques, forefoot vs rearfoot

Introduction: Surface electromyography has been a technique used to describe muscle activity during running. However, there is little literature that analyses the behaviour of muscle coactivation in runners, describing the effect between two techniques associated with the initial contact, such as the use of rearfoot (RF) and forefoot (FF). Material and method: The purpose of this study was to compare muscle coactivation levels developed in the lower limb during two running techniques, FF vs RF. Fourteen amateur runners were evaluated (eight men, six women; age= 23.21 ± 3.58 years, mass= 63.89 ± 8.13 kg, height= 1.68 ± 0.08m). Surface electromyography was used to measure muscle activity during both running techniques evaluated on a treadmill, considering the muscle pairs: Rectus femoris- Biceps femoris (RFe-BF), Lateral Gastrocnemius–Tibialis Anterior (LG-TA), and Medial Gastrocnemius - Tibialis Anterior (MG-TA). These were calculated in three windows considering ten running cycles (0-5%, 80-100%, and 0-100%). To compare FF vs RF t-student test for paired data was used. Results: It was observed significant differences in the MG-TA pair (FF= 18.42 ± 11.84% vs RF = 39.05 ± 13.28%, p = 0.0018 during 0-5%, and RFe-BF pair (FF = 42.38 ± 18.11% vs RF = 28.37 ± 17.2%, p = 0.0331) during 80-100% of the race. Conclusion: Our findings show that the behaviour of muscle coactivation is different between FF vs RF techniques if we analyze little windows in the running cycle. This could be associated with an increase in the joint stability between these short intervals, represented in the initial and final regions of the running cycle.

Return to Sport, integrating the process from conventional rehabilitation up to reconditioning: a narrative review

Introduction: The process of return to sport after injury, has traditionally been approached in 2 separate stages; first the athlete is treated the medical service through conventional rehabilitation processes and is then referred to the sports team (coach and / or physical trainer) who complete the return to the sport activity. This approach may lack communication and coordination between both teams and may be insufficient for the demands of the current sports environment, causing longer processes of return to sport and greater risk of re-injury. The objective of this manuscript is to document the current models of return to sport, its stages, objectives and contents. Material and method: A comprehensive review of publications was carried out, including observational studies, clinical trials, reviews, consensus, systematic reviews and meta-analysis, related to treatment, rehabilitation, readaptation and return to sport. Results: The description of a model of return to sports of gradual progression that includes 3 stages was found: return to participation, readaptation to sport and return to maximum sports performance. The stage of return to participation aims to eliminate the symptoms and regain the functionality of the athlete in their non-sports activities, through conventional rehabilitation processes. The stage of readaptation to sport aims to achieve asymptomatic performance of training and competition activities, through the rehabilitation of deficiencies caused by the injury and the maintenance and / or development of motor skills with modified training. The stage of return to maximum sports performance includes specific sports training to reach the level of performance prior to the injury. Conclusions: This model could be associated with greater success in returning to sports activity and lower risk of recurrence of the injury.