Effects of resistance training on performance in previously trained endurance runners: A systematic review

The aim of this work was to identify, synthesize and evaluate the results of randomized controlled trials examining the effects of resistance training on performance indicators in previously trained endurance runners. A database search was carried out in PubMed, Science Direct, OvidSPMedLine, Wiley, Web of Science, ProQuest and Google Scholar. In accordance with the PRISMA checklist, 18 published articles dated prior to May 2016 involving 321 endurance runners were reviewed using the PEDro scale. Resistance training led to general improvements in muscular strength, running economy, muscle power factors, and direct performance in distances between 1,500 and 10,000 m. Such improvements were not accompanied by a significant increase in body mass or signs of overtraining. However, improvements did not occur in all cases, suggesting that they might depend on the specific characteristics of the resistance training applied. Although current evidence supports the effectiveness of resistance training to improve performance in already trained endurance runners, the methodological inconsistencies identified suggest that the results should be interpreted with caution. Future studies ought to investigate the benefits of resistance training in endurance runners while considering the existence of possible differentiated effects based on the specific characteristics of the resistance training carried out.     

A Small‐Scale Randomized Efficacy Trial of the Identity Project: Promoting Adolescents’ Ethnic–Racial Identity Exploration and Resolution

Adolescents’ ethnic–racial identity (ERI) formation represents an important developmental process that is associated with adjustment. The Identity Project intervention, grounded in developmental theory, was designed to engage adolescents in the ERI processes of exploration and resolution. The current small‐scale efficacy trial involved an ethnic–racially diverse sample of adolescents (N = 215; M_age = 15.02, SD = .68) from eight classrooms that were randomly assigned by classroom to the intervention or attention control group. Differences between conditions in ERI exploration at Time 2 were consistent with desired intervention effects; furthermore, higher levels of ERI exploration at Time 2 predicted increases in ERI resolution at Time 3 only for youth in the treatment condition. Findings provide preliminary evidence of program efficacy.     

University surroundings and infrastructures that are accessible and inclusive for all: listening to students with disabilities

The main topic of this article is architectural barriers and infrastructures as identified by university students with disabilities. The data presented is part of a much wider research project, sponsored by Spain’s Ministry of Economy and Competition. A biographical-narrative methodology was used for this study. The results presented have been classified based on one of five barrier types: urban (barriers that are outside the actual university campus), transport (public transportation and personal vehicles), building (obstacles inside university buildings), environmental (those elements within the classroom, including furniture, excessive noise or inadequate temperatures) and communication (these are divided into signposting and barriers when accessing information). Lastly, a variety of questions are considered in the conclusions which indicate that universities still need a certain degree of adaptation and readjustment to really be accessible and inclusive, in keeping with the principles of universal design.     

Acute kinematics changes in marathon runners using different footwear

The effects of running with or without shoes on injury prevention have been extensively studied, and several investigations have assessed biomechanical differences between them. However, findings are not consensual and further insights on biomechanical load associated with differently shod or barefoot conditions may be needed. This study aimed to observe if habitually shod marathon runners show acute alterations when running barefoot or with minimalist shoes, and to determine whether the running kinematical adaptations of wearing minimalist shoes were similar to barefoot running. Twelve male marathon runners ran on the treadmill at their average marathon pace in different footwear conditions: habitual running shoes, minimalist shoes, and barefoot. High-resolution infrared cameras and visual 3D software were used to assess kinematic data. The following parameters were studied: foot strike angle, cycle time, stance time, normalized stride length, hip, knee, and ankle angular position at initial contact, and their respective range-of-motion (ROM) during stance phase. Contrary to the expectations, it was found that highly trained habitually shod elite marathon runners changed their lower limb kinematic pattern both when running barefoot or wearing minimalist shoes. Minimalist shoes showed a trend towards intermediate biomechanical effects between running with and without shoes.     

Developing a Human Nutrition Learning Progression

This paper describes the application of the methodology developed in research on learning progressions to a health-related topic. More specifically, we present a human nutrition learning progression as a hypothesis that now requires empirical validation. The study involved three phases. In the first phase, we analysed the existing literature in the domain of human nutrition. Based on this analysis, phase 2 then involved drawing up a learning progression for this domain and identifying the learning targets and progress variables, as well as the upper and lower anchors. The analysis led us to identify five progress variables, associated with the development of the concepts of food, nutrient, energy and diet, as well as with the ability to classify foods according to their nutrients. Finally, in phase 3, we identified and described the pathways that students may follow in relation to each progress variable. Given its focus on a topic closely linked to personal health, the learning progression may be useful not only as a component of teaching modules that aim to improve scientific literacy but also as a platform for future health education campaigns that seek to promote healthy eating habits among different sectors of the population.     

Clones identification of Sequoia sempervirens (D. Don) Endl. in Chile by using PCR-RAPDs technique

A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene diversity and genotype identification for clones of Sequoia sempervirens (D. Don) Endl. in Chile. Ten (out of 34) clones from introduction trial located in Voipir-Villarrica, Chile, were studied. The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction. The PCR tests were carried out employing 10-mer random primers. The amplification products were detected by electrophoresis in agarose gels. Forty nine polymorphic bands were obtained with the selected primers (BG04, BF07, BF12, BF13, and BF14) and were ordered according to their molecular size. The genetic similarity between samples was calculated by the Jaccard index and a dendrogram was constructed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGMA). Of the primers tested, 5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism. A total of 49 polymorphic RAPD bands were detected out of 252 bands. The genetic similarity analysis demonstrates an extensive genetic variability between the tested clones and the dendrogram depicts the genetic relationships among the clones, suggesting a geographic relationship. The results indicate that the RAPD markers permitted the identification of the assayed clones, although they are derived from the same geographic origin. Project (No. CONICYT-FONDEF PROYECT D01 I 1008) supported by the National Commission of Science and Research of Chile     

Information-governing dynamics of attacker–defender interactions in youth rugby union

Abstract

Previous work on dynamics of interpersonal interactions in 1 vs. 1 sub-phases of basketball has identified changes in interpersonal distance between an attacker and defender as a potential control parameter for influencing organizational states of attacker–defender dyads. Other studies have reported the constraining effect of relative velocity between an attacker and defender in 1 vs. 1 dyads. To evaluate the relationship between these candidate control parameters, we compared the impact of both interpersonal distance and relative velocity on the pattern-forming dynamics of attacker–defender dyads in the sport of rugby union. Results revealed that when interpersonal distance achieved a critical value of less than 4 m, and relative velocity values increased or were maintained above 1 m · s^?1, a successful outcome (i.e. clean attempt) for an attacker was predicted. Alternatively, when values of relative velocity suddenly decreased below this threshold, at the same critical value of interpersonal distance, a successful outcome for the defender was predicted. Data demonstrated how the coupling of these two potential, nested control parameters moved the dyadic system to phase transitions, characterized as a try or a tackle. Observations suggested that relative velocity increased its influence on the organization of attacker–defender dyads in rugby union over time as spatial proximity to the try line increased.     

Improvement of cellular health indicators and muscle quality in older women with different resistance training volumes

ABSTRACT

The main purpose of this study was to compare the effects of resistance training (RT) performed with different training volumes on phase angle (PhA), body water components, and muscle quality (MQ) in untrained older adult women. A second purpose was to assess the relationship between PhA and MQ. Sixty-two older adult women (68.6 ± 5.0 years, 65.2 ± 13.3 kg, 156.1 ± 6.2 cm) were randomly assigned into one of the three groups: two training groups performed either 1 set (G1S) or 3 sets (G3S), or a control group (CG). Body water components and PhA were estimated by bioelectrical impedance (BIA). MQ was determined by dividing skeletal muscle mass estimated by dual-energy absorptiometry (DXA) by total muscle strength from three exercises. After the intervention period, both training groups demonstrated improvements (P < 0.05) when compared with CON for intracellular water, total body water, PhA, and MQ. These results suggest that RT can improve PhA, body water components, and MQ after 12 weeks of RT in untrained older women, regardless of training volume. Furthermore, changes in MQ were positively correlated with changes in PhA (r = 0.60, P < 0.01).     

Reliability and validity of different methods of estimating the one-repetition maximum during the free-weight prone bench pull exercise

ABSTRACT

This study examined the reliability and validity of three methods of estimating the one-repetition maximum (1RM) during the free-weight prone bench pull exercise. Twenty-six men (22 rowers and four weightlifters) performed an incremental loading test until reaching their 1RM, followed by a set of repetitions-to-failure. Eighteen participants were re-tested to conduct the reliability analysis. The 1RM was estimated through the lifts-to-failure equations proposed by Lombardi and O’Connor, general load-velocity (L-V) relationships proposed by Sánchez-Medina and Loturco and the individual L-V relationships modelled using four (multiple-point method) or only two loads (two-point method). The direct method provided the highest reliability (coefficient of variation [CV] = 2.45% and intraclass correlation coefficient [ICC] = 0.97), followed by the Lombardi’s equation (CV = 3.44% and ICC = 0.94), and no meaningful differences were observed between the remaining methods (CV range = 4.95–6.89% and ICC range = 0.81–0.91). The lifts-to-failure equations overestimated the 1RM (3.43–4.08%), the general L-V relationship proposed by Sánchez-Medina underestimated the 1RM (?3.77%), and no significant differences were observed for the remaining prediction methods (?0.40–0.86%). The individual L-V relationship could be recommended as the most accurate method for predicting the 1RM during the free-weight prone bench pull exercise.     

Relationships between cardiorespiratory fitness,inhibition, and math fluency: A cluster analysis

ABSTRACT

This study identified clusters of adolescents who share similar cardiorespiratory fitness levels and analysed the relationships between cardiorespiratory fitness, inhibition, and math fluency in each of the clusters. The subjects were 490 high-school students aged 10–16 years. The mean age was 13.82 years (SD = 1.12). Latent class analysis identified three clusters with high, medium, and low levels of cardiorespiratory fitness. The high-fitness cluster achieved higher scores in inhibition and math fluency than the low-fitness cluster. Path analysis revealed that the influence of cardiorespiratory fitness on inhibition was non-existent in the three clusters. The effect of inhibition on math fluency was positive and significant in all three cardiorespiratory fitness levels. Cardiorespiratory fitness had a direct, positive, and significant effect on math fluency only in the high-fitness cluster. Therefore, a high level of cardiorespiratory fitness is a significant determining factor in the explanation of math fluency. These results indicate that inhibition does not mediate the relationship between cardiorespiratory fitness and math fluency. However, the benefits of cardiorespiratory fitness affect math fluency, which has important implications for the educational environment and the teaching/learning process.