Association between knee-to-hip flexion ratio during single-leg vertical landings,and strength and range of motion in professional soccer players

Abstract

The aim of this study was to test the correlation between knee-to-hip flexion ratio during a single leg landing task and hip and knee strength, and ankle range of motion. Twenty-four male participants from a professional soccer team performed a continuous single leg jump-landing test during 10s, while lower limb kinematics data were collected using a motion analysis system. After biomechanical testing, maximal isometric hip (abduction, extension, external rotation), knee extension and flexion strength were measured. Maximum ankle dorsiflexion range of motion was assessed statically using the weight bearing lunge test. Pearson correlation coefficients were calculated to determine the associations between the predictor variables (knee and hip strength, and ankle ROM) and the main outcome measure (knee-to-hip flexion ratio). Correlation between knee-to-hip flexion ratio and hip abductors strength was significant (r = ?0.47; p = 0.019). No other significant correlations were observed among the variables (p > 0.05). These results demonstrated that a lower hip abductors strength in male soccer players was correlated with a high knee-to-hip flexion ratio during landing from a single leg jump, potentially increasing knee overload by decreasing energy absorption at the hip. The results provide a novel proposal for the functioning of hip muscles to control knee overload.     

The effect of smartphones and playing video games on decision-making in soccer players: A crossover and randomised study

ABSTRACT

The objective of this study was to analyse the effect of the use of social networks in smartphones or playing video games on the passing decision-making performance in professional soccer athletes. Participants were 25 male professional soccer athletes (mean ± SD: age 23.4 ± 2.8 years). The participants performed three randomised conditions divided into three groups: control (CON), smartphone (SMA), and video game (VID). Before and after each experimental condition, the Stroop Task assessed the level of induced mental fatigue. Then, the athletes performed a simulated soccer match. A CANON® camera recorded the matches for further analysis on passing decision-making performance. A group effect was identified (p < .01) with impairment on passing decision-making performance for the SMA (p = .01, ES = 0.5) and VID (p = .01, ES = 0.5) conditions. We concluded that the use of social networks on smartphones and/or playing video games right before official soccer matches might impair the passing decision-making performance in professional soccer athletes.     

Cross-Cultural Adaptation and Psychometric Properties of the Portuguese Version of the Life Skills Scale for Sport

ABSTRACT

This research adapted the Life Skills Scale for Sport (LSSS) into Portuguese and provided evidence for its construct validity. Study 1 included four translators and five academics who developed a Portuguese version of the LSSS (P-LSSS). During this study, evidence for the content and substantive aspects of construct validity was provided using an expert panel and 25 sports participants. Study 2 included 413 participants that completed the P-LSSS. Within this study, evidence for the structural aspect of construct validity was provided via factor analyses. Study 3 included 134 participants who completed the P-LSSS and a measure of motivation. This study provided evidence for the external aspect of construct validity, with results showing more self-determined motivation had positive relationships with participant’s life skills development. Overall, our findings provided evidence for the construct validity of P-LSSS scores. Researchers and practitioners can use the P-LSSS to assess life skills development within sports participants.     

Action groups as a participative strategy for leading whole-school health promotion: Results on implementation from the INCLUSIVE trial in English secondary schools

Education policy increasingly promotes action groups as a key strategy for student and/or staff participation in school improvement and whole-school health promotion. Such groups can coordinate multi-component interventions, increase participation and engagement, and enable local adaptations, but few process evaluations have assessed this. We evaluated fidelity, feasibility and acceptability of action groups as part of a trial of a whole-school intervention to reduce bullying and aggression and promote health in English secondary schools, which reported multiple health and educational impacts. Action groups involved students and staff, supported by external facilitators, and drew on data on student needs. They aimed to: coordinate implementation of restorative practices and a social and emotional competencies curriculum; review policies and rules; and enact local decisions to modify school environments. Our process evaluation used interviews, focus groups, observations and questionnaires to assess action groups’ fidelity, role in coordination, role in local adaptation, support from external facilitators and data on student needs, and acceptability in engaging members. Fidelity was high in the first two years but lower in the third year when external facilitators withdrew. Student needs data were perceived as useful, but views on external facilitators were mixed. Groups successfully reviewed policies and rules, planned activities and coordinated restorative practices, but were less successful in implementing the curriculum. Success was facilitated by the involvement of school leaders. Members reported high satisfaction and empowerment. Action groups are a promising strategy for leading whole-school health promotion. Implementation is supported by external facilitation, local data and involvement of senior managers.     

User experience of government documents: A framework for informing design decisions

People still use documents in many everyday government processes. From tax payments to passport requests, citizens have to interact with low-interactivity information artifacts such as reports, maps and datasets, among many others. Despite efforts to improve information delivery in the public sector, effective information usage remains a critical topic of action and research. The user experience of government documents has rarely been assessed, despite them being regularly published and frequently used. Considering this, the two following research questions arise: 1) How can government documents be classified (or grouped) in terms of user experience? 2) How can the user experience of government documents be monitored over time in order to inform design decisions? Working with a public agency in Chile, we develop and test a classification and monitoring framework based on two online surveys (N?=?338 and N?=?298). We then propose a framework for understanding user experience of government documents in these three dimensions: interaction goal, volume of information and ease of understanding. Using a graphical representation to classify user experience provides greater visibility of the current status of information produced by a public organization. Furthermore, by monitoring the user experience of a government document at different times, organizations can understand the effect of their design decisions and improve their service quality by implementing user-centered processes.     

Coherence estimate between a random and a periodic signal: Bias, variance, analytical critical values, and normalizing transforms

The present work deals with recent results on the sampling distribution of the magnitude-squared coherence (also called just coherence) estimate between a random (Gaussian) and a periodic signal, in order to obtain analytical critical values, alternative expressions for the probability density function (PDF) as well as the variance and bias of the estimate. A comparison with the more general case of coherence estimation when both signals are Gaussian was also provided. The results indicate that the smaller the true coherence (TC) values the closer both distributions become. The behaviour of variance and bias as a function of the number of data segments and the TC is similar for both coherence estimates. Additionally, the effect of a normalizing function (Fisher's z transform) in the coherence estimated between a random and a periodic signal was also evaluated and normality has been nearly achieved. However, the variance was less equalized in comparison with coherence estimate between two Gaussian signals.     

Alternative assessment of knee joint muscle balance of soccer players through total work-based hamstring: quadriceps ratios

Isokinetic hamstring-to-quadriceps (H:Q) ratios are frequently used to assess knee muscle strength imbalances and risk of injuries/re-injuries. The use of peak torque (PT) or total work (TW) to estimate joint stability may lead to different results because of the differences between these two neuromuscular variables. Thus, the current study aimed to compare the conventional and functional H:Q ratios calculated by PT and TW. Ninety-three male professional soccer players from Brazilian first division teams performed isokinetic concentric and eccentric contractions of the quadriceps and the hamstrings at 60°/s. Muscle strength balance was calculated using the conventional torque ratio (CTR) and conventional work ratio (CWR), functional torque ratio (FTR) and functional work ratio (FWR) were highly and moderately correlated between them (r?=?0.83 and r?=?0.73, respectively). The Wilcoxon statistical test revealed significant differences between CTR and CWR, as well as FTR and FWR (p?T-test demonstrated significant differences in mean CTR–CWR and FTR–FWR, whereas Bland–Altman plots showed non-consistent bias. In addition, the chi-square test demonstrated significant differences between players below the conventional reference values and functional reference values (p?相似文献   

Effect of Dehydration on Passing Decision Making in Soccer Athletes

It seems that dehydration may impair decision-making performance in athletes. Purpose: This study aimed to investigate the influence of dehydration on passing decision-making performance in soccer players. Method: Participants were 40 male soccer players (M_age = 22.3 ± 2.3 years) who agreed to participate in the study and were randomly assigned to the following conditions: control (CON), dehydration (DEH), and euhydration (EUH). The players played in 2 games of 90 min in duration (2 45-min halves) followed by 2 15-min halves (overtime) with and without proper hydration. The Game Performance Assessment Instrument (GPAI) was considered for the analysis of passing decision making. Results: The GPAI analysis indicated effective reduction in the decision-making index in the DEH condition compared with the EUH and CON conditions, F(2, 38) = 31.4, p < .05, ES = 0.8. Conclusions: In conclusion, dehydration may be considered a mediating factor in the passing decision-making performance of male soccer athletes.     

Tandem array of nanoelectronic readers embedded coplanar to a fluidic nanochannel for correlated single biopolymer analysis

We have developed a two-step electron-beam lithography process to fabricate a tandem array of three pairs of tip-like gold nanoelectronic detectors with electrode gap size as small as 9 nm, embedded in a coplanar fashion to 60 nm deep, 100 nm wide, and up to 150 μm long nanochannels coupled to a world-micro-nanofluidic interface for easy sample introduction. Experimental tests with a sealed device using DNA-protein complexes demonstrate the coplanarity of the nanoelectrodes to the nanochannel surface. Further, this device could improve transverse current detection by correlated time-of-flight measurements of translocating samples, and serve as an autocalibrated velocimeter and nanoscale tandem Coulter counters for single molecule analysis of heterogeneous samples.     

Evaluation of retirement planning programs: A qualitative analysis of methodologies and efficacy

ABSTRACT

The objective of this integrative literature review was to evaluate the quality of retirement planning programs described in the extant literature. This was accomplished through a qualitative analysis of methodological and efficacy criteria as described by Flay et al. (2005), Kazdin (2010, 2011 and Murta (2005). Several databases were consulted in searching for retirement program articles including: Academic Search Premier, Medline, PsycInfo, and Web of Science, among others. Retirement planning intervention articles published in English, Portuguese, and Spanish were considered, with a focus on their evaluation methods and results. Eleven studies were identified that described the procedures for both program implementation and intervention evaluation. Results revealed methodological shortcomings in the papers reviewed, with concerns being related to a lack of experimental or quasiexperimental approaches, a failure to use previously validated measurement instruments and longitudinal assessments, and insufficiently robust data analysis procedures. That said, however, there was evidence from multiple investigations that the intervention programs examined led to increases in knowledge, positive changes in attitudes linked to retirement, and an increase in retirement-linked planning and preparation behaviors. Identification of strengths and weaknesses in the methods used and efficacy of these interventions could facilitate the construction of a research agenda aimed at promoting more favorable research designs. Use of more rigorous designs would stand to improve the internal validity of these retirement programs and, consequently, progress in this field.