Disparities among nations in the summer Olympics are often ascribed to long-lasting climatic influences. In this study, we examined six Summer Games (1996–2016) to investigate the potential correlation between climatic origin and national Olympic success in 12 dissimilar sports categories. We measured total success by medal tallies (MT) and the revealed symmetric comparative advantage (CA). Using Tobit regression, we tested the effect of four generic climates (Dry–Arid, Tropical–Equatorial, Warm–Humid, Cool–Humid) against the covariation of population, gross domestic product and the socialist system. The Tobit models were significant both for MT (ρ2 = 0.20–0.73) and CA (ρ2 = 0.08–0.54). With a few minor exceptions (Weights, Aquatics/Water, Combat) much of the variation in MT and CA was explained by the three covariates. Inter-nation disparities in Olympic performance are unrelated to climatic origin. The previously observed ‘advantage’ of the Temperate climate is discussed considering the strong ‘socialist’ covariate.

This study documented the change in study design and statistics employed in applied sports and exercise biomechanics research from 1985 to 2014. The sample comprised 676 data based original research reports published in the Journal of Applied Biomechanics (JAB) from 1985 to 2014. Eight design and 10 statistical criteria were extracted from each study. Descriptive statistics were calculated and change in study criteria over time were documented. Design criteria that did not change over time, remaining at relatively low levels of rigor, were widespread (71%) use of small (2-20) sample sizes and examination of numerous dependent variables (26.6% with >13). The number of experimental groups and independent variables also did not change with typically 1 to 2 reported. There was a significant 61% linear increase in randomization of participants into groups, however by 2014 still a minority (39%) of studies were not reporting randomized assignment. Types of statistical analysis showed positive changes over time with a 48% quadratic decrease in descriptive analyses, a 3% linear increase in nonparametric statistics, and a 45% linear increase in reporting parametric statistical analysis. Changes in specific statistical methods included a 9% linear decrease in bivariate correlation and a 73% linear increase in ANOVA. Reporting of assumptions had a 35% linear increase, yet in 2014 sixty-five percent still did not report on meeting statistical assumptions. Changes in test statistics included a linear 56% increase of reporting observed P values and a quadratic 29% increase in reporting effect sizes beginning in the late 1990s. It was concluded there was evidence of small improvements in research design and statistics in JAB over the last 30 years; however, there is still room for improvement to meet higher levels of research rigor and current recommendations on statistical analysis and reporting.

The purpose of this meta-analysis was to examine the effectiveness of Mosston and Ashworth’s (2008) practice and reciprocal styles of teaching on motor skill acquisition of school and university students. A systematic search in bibliographical databases led to the identification of 23 relevant studies published in peer-reviewed journals. Using certain methodological and statistical criteria, we retained six studies for further analysis. We estimated proper Effect Size (ES) statistics for each study and each teaching style. Heterogeneity of the ESs was almost negligence for the reciprocal style and moderate to large for the practice style (I2 > 50%). Both teaching styles appear to produce rather large effects, with the practice style (mean d = 1.16) having larger effects than the reciprocal style (mean d = 0.94). This meta-analysis provides an overview and synthesis of relevant studies and highlights both teaching styles for increasing K-12 and university students’ motor skill learning. The results are discussed in light of the Spectrum theory.   Keywords: meta-analysis, Spectrum, practice style, reciprocal style, motor skill

This study investigated the relationship between somatotype, level of competition, and performance in attack in elite level male volleyball players. The objective was to test for the potential covariation of competition level (Division A1 vs. A2) and playing position (hitters vs. centers vs. opposites) considering performance in attack. Anthropometric, body composition and somatotype variables were measured according to the Heath-Carter method. The attack actions of 144 players from 48 volleyball matches were analyzed and their performance was rated using a 5-point numerical scale. Results showed that players of Division A1 were taller, heavier, more muscular, and less endomorphic compared to those of Division A2. MANOVA and follow-up discriminant function analysis revealed somatotype differences among playing positions with centers and opposites being endomorph-ectomorph and hitters being central. Centers performed constantly better than hitters and opposites regardless of division and somatotype. Multiple linear regression analysis showed that variables defining ectomorph and endomorph players, centers, and players of Division A1 significantly determined the relative performance superiority and were able to explain the variation in performance by almost 25%. These results could be taken into account by coaches when assigning players to particular playing positions or when designing individualized position-specific training programs.

We investigated the effectiveness of two teaching formats that fall under the canopy of Mosston and Ashworth’s (2008) practice style, on fifth grade students’ motor skill performance and task engagement. Both formats are also known as station teaching or learning centers. In the teacher-rotated format (TR), the teacher decides the amount of time apportioned during practice at each station, whereas in the learner-rotated format (LR), each learner decides on task order and the amount of time spent at each station. Ten-year-old children (N = 60) were randomly assigned to the TR group (n = 20), the LR group (n = 25), and a control group (n = 15). A soccer dribbling test was employed to evaluate the soccer dribbling skill prior to and after the instructional intervention. The same soccer dribbling tasks were taught to the learners in both treatment groups in eight 30-min sessions. ANCOVA on the posttest scores showed a significant difference between the experimental groups and the control group (p < .001) and between the two experimental groups, favoring the LR group (p < .001). A 3 × 2 (Group × Test) repeated measures ANOVA showed a significant improvement of the soccer dribbling skill for both teaching formats (p < .001) but not for the control group. An ANOVA on the overall practice trial data yielded significant differences between the two formats, favoring the LR group (p < .001). Both formats were found to be effective, but the results indicate that given the opportunity to reapportion their practice time, learners in the LR format took advantage of this opportunity and improved their performance further.

The fatiguing effect of long-distance running has been examined in the context of a variety of parameters. However, there is scarcity of data regarding its effect on the vertical jump mechanics. The purpose of this study was to investigate the alterations of countermovement jump (CMJ) mechanics after a half-marathon mountain race. Twenty-seven runners performed CMJs before the race (Pre), immediately after the race (Post 1) and five minutes after Post 1 (Post 2). Instantaneous and ensemble-average analysis focused on jump height and, the maximum peaks and time-to-maximum peaks of: Displacement, vertical force (Fz), anterior-posterior force (Fx), Velocity and Power, in the eccentric (tECC) and concentric (tCON) phase of the jump, respectively. Repeated measures ANOVAs were used for statistical analysis (p ≤ 0.05). The jump height decrease was significant in Post 2 (-7.9%) but not in Post 1 (-4.1%). Fx and Velocity decreased significantly in both Post 1 (only in tECC) and Post 2 (both tECC and tCON). Α timing shift of the Fz peaks (earlier during tECC and later during tCON) and altered relative peak times (only in tECC) were also observed. Ensemble-average analysis revealed several time intervals of significant post-race alterations and a timing shift in the Fz-Velocity loop. An overall trend of lowered post-race jump output and mechanics was characterised by altered jump timing, restricted anterior-posterior movement and altered force-velocity relations. The specificity of mountain running fatigue to eccentric muscle work, appears to be reflected in the different time order of the post-race reductions, with the eccentric phase reductions preceding those of the concentric one. Thus, those who engage in mountain running should particularly consider downhill training to optimise eccentric muscular action.

The assessment of dietary attitudes and behaviors provides information of interest to sports nutritionists. Although there has been little analysis of the quality of research undertaken in this field, there is evidence of a number of flaws and methodological concerns in some of the studies in the available literature. This review undertook a systematic assessment of the attributes of research assessing the nutritional knowledge and attitudes of athletes and coaches. Sixty questionnaire-based studies were identified by a search of official databases using specific key terms with subsequent analysis by certain inclusion–exclusion criteria. These studies were then analyzed using 33 research quality criteria related to the methods, questionnaires, and statistics used. We found that many studies did not provide information on critical issues such as research hypotheses (92%), the gaining of ethics approval (50%) or informed consent (35%), or acknowledgment of limitations in the implementation of studies or interpretation of data (72%). Many of the samples were non-probabilistic (85%) and rather small (42%). Many questionnaires were of unknown origin (30%), validity (72%), and reliability (70%) and resulted in low (≤ 60%) response rates (38%). Pilot testing was not undertaken in 67% of the studies. Few studies dealt with sample size (2%), power (3%), assumptions (7%), confidence intervals (3%), or effect sizes (3%). Improving some of these problems and deficits may enhance future research in this field.

Biomechanical findings show that running is asymmetric in many kinetic properties. Running stiffness is a vital kinetic property of yet unknown pattern of lateralization. The aim of this study was to examine the degree and variability of lower limb dominance specific asymmetry of running in terms of leg stiffness, vertical stiffness, contact time, flight time, maximal ground reaction forceduring contact, vertical displacement of the center of mass, and change in leg length. Leg and vertical stiffness was estimated by the sine-wave method in 22 young males during treadmill runningat 4.44m/s. Lower limb dominance was determined by the triple jump test. Asymmetry was expressed as dominant – non-dominant, and indexed by the absolute asymmetry index. Significant asymmetry was found only in flight time (3.98%) and in maximal ground reaction force (1.75%). The absolute asymmetry index ranged from 1.8% to 6.4%, showed high variation between subjects (0–31.6%), and differentiated among the 7 analyzed variables. Leg and vertical stiffness in treadmill running of moderate pace (4.44 m/s) should be considered symmetric.

Overweight and obesity are widespread nutritional disorders. Their treatment aims at effective weight loss (WL) and weight loss maintenance (WLM). Previous systematic reviews show weight regain, after recommended exercise and diet combined. However, certain experimental and methodological inconsistencies in the original studies and in these reviews left space for a substantial revisit of this problem. This study aimed at systematically re-reviewing the effectiveness of exercise combined with diet on WLM in overweight and obese adults. Literature was searched through Embase and Sport Discus (up to 2008), and PubMed (Medline) and ISI Web of science (up to 2012). 14 randomized clinical trials (RCT) were retained, their quality was assessed by the Jadad scale, and detailed methodological and statistical characteristics were evaluated. Overall estimations showed a WL of 11.1 kg (about 13%) after an average of about 4 months from baseline, a WLM of 5.8 kg (about 52%) and a weight regain of 5.1 kg after an average period of about 21 months. WL was successful but almost half of it (about 48%) was regained, which agrees with previous findings. The Jadad score showed very good to excellent quality for all 14 studies. However, further assessment revealed serious weakness such as high average dropout (>20%), not estimating experimental power or not using a control group in more than half of the studies, possible lack of adherence and variability in demographic traits. Future studies may focus on improving these limitations for more accurate results in this crucial research field.

Joint hypermobility syndrome (JHS) is a heritable disorder of the connective tissue characterized by excessive joint movement, musculoskeletal pain and neurophysiological deficits (i.e. decreased proprioceptive acuity, altered neuromuscular reflexes). Such deficits may affect body balance thus increasing the risk of injury. The present study aimed at examining static and dynamic body balance following challenge of the visual and vestibular systems in individuals with JHS. The sample consisted of 21 females with JHS and 20 controls without signs of JHS. Static body balance was assessed by the degree of anteroposterior and mediolateral deviation of the center of pressure, during 20-sec single-leg stances with eyes opened (EO), eyes closed (EC) and eyes opened with head extension (EO-HE) using a foot pressure platform. Dynamic body balance was assessed by the number of landing and balance errors committed during a multiple single-leg-hop-stabilization test. Nonparametric analysis showed that the JHS-group demonstrated significantly greater (a) mediolateral deviation during single-leg-stance with EO (p < 0.01), (b) mediolateral and anteroposterior deviation during single-leg-stance with EO-HE (p < 0.05), and (c) number of landing errors (p < 0.05) compared to the control group. Poor static balance following challenge of the vestibular system may be justified by vestibular deficiency and/or insufficient proprioceptive capabilities of the neck. Impairments of dynamic balance in individuals with JHS may be attributed to proprioceptive deficits, which can alter feedforward and feedback mechanisms.

In the study and teaching of folk dance the determination of the syntactical rules that shape the interdependence between the structural elements of dance and music remains a major topic of interscientific interest. Therefore, the aim of the present research was the multivariate categorical analysis of Greek folk dances according to their resemblance in structure and form to the type of a widespread Greek folk dance “choros sta tria.” The multivariate analysis was conducted on the qualitative findings of Tyrovola’s study (1994) which with the use of the structural-morphological method for the analysis of dance: a) documented the structural type of “choros sta tria,” b) showed its homogeneity with 132 Greek folk dances and c) proposed four taxonomic categories of dance form for their classifi cation. 122 dances of Tyrovola’s research were used in the present study and were categorized according to two independent variables (factors): a) category of dance form (identical, heteromorphic, varied, and remodeled-related dance forms), and b) geographic area (terrestrial and insular areas of the country). Nine distinct and variant properties of the dance form of “choros sta tria” were used as dependent variables: music meter, tempo, dynamics, dance handhold, dance formation, number and kind of kinetic elements of the 2nd part of the semifinal and final kinetic dance motifs, model of dance form. The correlational structure of the nine dance properties and the two factors were tested by a series of chi square (χ2) analyses (nonparametric univariate approach) and non-linear canonical correlation analyses (multivariate approach). The results of these analyses indicated that there is a significant difference between the terrestrial and insulardistribution of Greek dances across the four levels of dance form. The geographical differentiation of the dances in terrestrial or insular was mainly based on the properties of metro, tempo, dynamics, and dance formation, while the morphological differentiation in identical, heteromorphic, varied, remodeled-related dance forms was based on the interaction between the elements of their rhythmical organization and the variations of their basic structural type. The application of these statistical methods of analysis in thestudy of structure and style of Greek folk dances proved to be very efficient in unveiling critical aspects of their multivariate domain. The morphological method of dance analysis combined with statistical methods may enhance research in this area, enriching thus already documented findings regarding the substantial dimensions of this multi-factorial phenomenon.

Background: Ankle sprain is an extremely common injury in soccer players. Despite extensive research, the intrinsic cause of this injury under noncontact conditions remains unclear. Purpose: To identify intrinsic risk factors for noncontact ankle sprains in professional soccer players. Study Design: Cohort study; Level of evidence, 2. Methods: One hundred professional soccer players were assessed in the preseason for potential risk factors of noncontact ankle. sprains. The assessment included (A) ankle joint asymmetries (right-left) in isokinetic muscle strength, flexibility, proprioception. and stability; (B) somatometric asymmetries; (C) previous injuries; and (D) lateral dominance traits. Noncontact ankle sprains were prospectively recorded and diagnosed for a full competition period (10 months). Results: Seventeen of the players sustained at least 1 noncontact ankle sprain. Logistic regression revealed that players with (A) eccentric isokinetic ankle flexion strength asymmetries (odds ratio [OR] = 8.88; 95% confidence interval [CI], 1.95-40.36, P = .005), (B) increased body mass index (OR = 8.16; 95% CI, 1.42-46.63, P = .018), and (C) increased body weight (OR = 5.72; 95% CI, 1.37-23.95, P = .017 ) each had a significantly higher risk of a noncontact ankle sprain. A trend for younger players(OR = 0.28; 95% CI, 0.061-1.24, P = .092) and for players with ankle laxity asymmetries (OR = 3.38; 95% CI, 0.82-14.00, P = .093) to be at greater risk for ankle sprain was also apparent to the limit of statistical significance (.05<P<.10). Conclusion: Functional strength asymmetries of the ankle flexors and increased body mass index and body weight raise the propensity for ankle sprains in professional soccer players. Age and asymmetries in ankle laxity are potential factors worth revisiting, as there was an indication for younger players and players with ankle instability to be at higher risk for ankle injury. Proper preseason evaluation may improve prevention strategies for this type of injury in soccer.

The present study revisited the problem of estimating Olympic success by critical demo-economic indicators. The sample consisted of the 75 winner countries at the Athens 2004 Olympic Games (not previously analyzed). Medal totals were log-linearly regressed on land, population, GDP, urban population, inflation, growth rate, unemployment, labor force, health expenditures, ex-host, and team size. Multiple regression assumptions were tested with proper diagnostics including collinearity. Olympic team size was the best single predictors of Olympic medals (R2 = 0.690, p < 0.001), and as an alternative criterion variable was significantly regressed on population, growth rate, health expenditure, and unemployment (R2 = 0.563, p < 0.001). Medal totals were significantly regressed on population, ex-host, health expenditure, growth rate, and unemployment (R2 = 0.541, p < 0.001). The classical population-GDP model extracted only 28% of the variance in total medals (R2 = 0.277, p < 0.001), and this was slightly improved when combined with unemployment (R2 = 0.365, p < 0.001). It appears that the size of the Olympic team plays the role of transmitting the composite impact of a country's size and economy to the end-phase of Olympic success. Winning Olympic medals depends on the combined potential of population, wealth, growth rate, unemployment, ex-host, and social-sport expenditures. Larger and wealthier countries win more medals by “producing” larger Olympic teams as a result of possessing more athletic talents and better support for social and sport related activities.

The purpose of this study was to identify, categorize, and analyze published process-product research on physical education teaching methods completed between1960 and 2009. A literature search utilizing electronic databases yielded 138 studies which met the criteria for inclusion in the analysis. Each study was analyzed to obtain information on (a) the decade the study was published, (b) the number of authors, (c) the publication outlet, (d) the type of class, (e) the sampling method, (f) the effect size, (g) the statistics used, and (h) the statistical assumptions. The results indicated that most studies were the result of collaboration efforts among researchers. Also, intact classes rather than randomization were the most common technique used for forming the experimental groups. In the majority of the studies, the selection of the sample was done by means of purposive sampling techniques. A large proportion of the studies used univariate statistics to complete the data analysis.  However, the majority of the papers reviewed did not report effect size values nor did they report fulfillment of certain statistical assumptions.  The major publication outlet for process-product research was the Journal of Teaching in Physical Education.

Objectives To identify the intrinsic risk factors of non-contact strains in the hamstrings and quadriceps muscles of professional soccer players via a cohort prospective design. Methods A total of 100 professional soccer players (aged 19.4–27.8 years) from four professional teams underwent a composite musculoskeletal assessment at preseason. Intrinsic risk factors included dichotomies of asymmetries in muscle strength, flexibility, proprioception, anthropometry and knee joint stability, and of previous injuries. Muscle strains were prospectively monitored during the subsequent season using questionnaires. The data were analysed via binary logistic regression.Results Thirty-eight percent of the players sustained one or more lower-extremity muscle strains. Sixteen (42.1 %) and seven (18.4 %) of them were clinically diagnosed as having non-contact muscle strains at their hamstrings and quadriceps, respectively. Players with eccentric hamstring strength asymmetries (OR=3.88; 95% CI 1.13 to 13.23), functional leg length asymmetries (OR=3.80; 95% CI 1.08 to 13.33) and no previous hamstrings injuries (OR=0.15; 95% CI 0.029 to 0.79) were at greater risk of sustaining a hamstring muscle strain. Players with eccentric strength (OR=5.01; 95% CI 0.92 to 27.14) and flexibility asymmetries (OR=4.98; 95% CI 0.78 to 31.80) in their quadriceps as well as heavier (OR=10.70; 95% CI 0.73 to 156.37) and shorter players (OR=0.08; 95% CI 0.00 to 1.35) were at greater risk of sustaining a strain in this muscle group. Conclusions Professional soccer players with functional asymmetries possess a higher risk of sustaining hamstring strains. Previous injury seems not to constitute a risk factor. The systematic isokinetic evaluation of the lower extremities during the preseason period can provide therapists and trainers with valuable data regarding the predictive elements of non-contact hamstring strains in professional soccer players.

The purpose of the present study was to assess the relative importance of selected performance indicators in modern top-level handball through the analysis of offensive actions in three consecutive men’s world championships (2005, 2007 and 2009). A total of 288 matches were examined, which included 29,439 throw attempts resulting in 16,240 goals. The results demonstrated the strong relationship between the six-meter and nine-meter offensive actions, as evidenced by their very high negative correlation coefficients in both the throw attempts and goals scored. The significant decrease of the throw attempts and goals scored from the six-meter position, evidenced in the 2007 and 2009 championships, is associated with the collateral significant increase of the nine-meter throws and goals. Interestingly, the nine-meter efficacy remained relatively constant throughout the three competition years, while the six-meter efficacy depicted a significant increase in competition years 2007 and 2009 compared to 2005, as a result of the appearance of highlyqualified top ranking players in the pivot position. The high performance efficiency of these players resulted in adaptive defensive tactics to prevent the ball from reaching this key position. The present findings provide valuable information to handball coaches, in the design of their strategic and tactical plans.

The aim of this study was to identify volleyball performance indicators that best discriminate between winning and losing teams in a set according to set final score differences. The data were collected from teams’ performances (N=350) in all sets played during the 2009 Men’s European Volleyball Championship in Turkey. Clusters analysisestablished three different groups of sets according to set final score difference: 2 points (ambivalent), 3-5 points (safe), >5 points (unbalanced). A 3x2 MANOVA (type of set x type of result) was then performed on 9 performance indicators reflecting % expressions of four basic skills of the game (serve, pass, attack, block). The analysis revealed significant multivariate differences in type of set, in type of results, and in their interaction. A follow-up Discriminant Analysis showed that effectiveness of attack is the most important performance indicator for all types of sets, far more for the ambivalent ones. The discriminant function correctly classified increasing % of cases with increase in score difference. Especially for ambivalent sets 67.3% were correctly classified, letting some space for further improving the critical performance indicators. The results suggest that training of a men’s volleyball teamshould emphasize more to improve offensive abilities.

Are Eccentric Strength Asymmetries Connected with Increased Risk for Muscle Injuries in the Thigh Muscles of Professional Soccer Players? Konstantinos Fousekis, Elias Τsepis, George Vagenas Introduction. The purpose of this prospective study was to statistically evaluate the relation between isokinetic strength asymmetries and risk of non-contact muscle strains in soccer. Methods. One hundred professional soccer players (age 23.4±4.8 years, height 178±6.7 cm, body mass 74.2±7.6 kg) were tested for isokinetic concentric and eccentric strength during the extension and flexion of the knee and ankle joint. Isokinetic testing was carried-out concentrically at 60o /sec. 180o/sec & 300o/sec and eccentrically at 60o/sec & 180o/sec for the knee joint. The ankle joint was tested at 60o/sec for both the concentric and eccentric mode of action. Each players? non-contact muscle strains resulting in missing at least one practise session or game were recorded during one competition season. Results. Analysis of the composite muscle strength asymmetries showed a significantly high relative risk of injury for players with eccentric strength asymmetries greater than 15% (RR=5.10; 95% CI: 1.29-20.17). Τhe majority of muscle strains involved 16% the hamstrings and 7% the quadriceps. The relative risk for strains in knee extensors strains was significantly increased in players with eccentric muscle asymmetries >15% (RR=1.93, 95% CI: 0.81- 4.56) and approximated statistical significance in the case of knee flexors strains (RR=1.82, 95% CI: 0.86-3.87). No significant relationship was found between concentric muscle strength asymmetries and muscle strains. Conclusions. Players with eccentric isokinetic strength asymmetries higher than 15% were more prone to injure their lower extremities. Preseason eccentric isokinetic assessment is required for the identification of soccer players being at high risk of thigh muscle strain and for the prevention of potential muscle strains via individualized exercise protocols.