The effects of static stretching on speed and agility: One or multiple repetition protocols?

Although static stretching (SS) is utilized during warm-up before training and competition, the results about its effects on performance remain controversial. We examined whether performing a stretch of short-to-moderate duration (<60 sec) in a single repetition produces a similar or different effect on speed and agility performance from the effect which is produced while performing the same stretch in multiple repetitions of the same total duration. According to a repeated measurement design, 40 trained males were randomly assigned to either (1) a single repetition group or (2) a multiple repetition group. The participants in each group performed five trials: a control trial (no stretches were performed) and four experimental trials of SS protocols consisting of five exercises performed at either 20 sec (2 × 10 in the second group), 30 sec (3 × 10 in the second group), 40 sec (4 × 10 in the second group) or 60 sec (6 × 10 in the second group) of total duration. A two-way repeated measures analysis of variance showed that the participants in both group improved their speed performance in response to the 20-sec trial, whereas agility remained unaffected. Data analysis also revealed that the repetition number did not affect speed and agility performance. These data suggest that SS of short duration (<30 sec) may actually improve acute speed performance, whereas SS of moderate duration may not hamper speed and agility performance. Moreover, the effects of SS protocols are related to the total duration of each exercise and not to the number of repetitions in which each exercise is performed.     

Effects of psychosocial variables in the similarity and interdependence of physical activity levels among adolescent best friend dyads

Given that physical activity (PA) tends to decrease with age during adolescence, addressing factors that affect change is important. This study examined the similarity and interdependence of PA as influenced by psychosocial factors among adolescent best friend dyads. A total of 660 adolescents, representing 330 best friend dyads, completed questionnaires with regard to PA, sitting time, perceived exercise benefits and barriers, physical self-perception and social support for PA. Dyads were also identified as reciprocal and non-reciprocal best friends; reciprocal means that both considered each other best friends and non-reciprocal were those in which only one considered the other a best friend. Data were analysed using a hierarchical linear model framework. Results indicated significant similarities between reciprocal best friend dyads for PA and sitting time, and for sitting time in non-reciprocal best friends (P values <.01). Psychosocial variables were associated with PA in reciprocal best friend dyads and with sitting time in reciprocal and non-reciprocal best friend dyads. Best friend gender, regular sports practice of the person, perceived exercise barriers of the best friend and best friend social support were the best predictors for PA.     

Effects of 12 weeks of combined training without caloric restriction on inflammatory markers in overweight girls

The objective of the present study was to investigate the effects of combined training without caloric restriction on inflammatory markers in overweight girls. Thirty-three girls (13–17 years) were assigned into overweight training (n = 17) or overweight control (n = 16) groups. Additionally, a normal-weight group (n = 15) was used as control for the baseline values. The combined training programme consisted of six resistance exercises (three sets of 6–10 repetitions at 60–70% 1 RM) followed by 30 min of aerobic exercise (walking/running) at 50–80% VO_2peak, performed in the same 60 min session, 3 days/weeks, for 12 weeks. Body composition, dietary intake, aerobic fitness (VO_2peak), muscular strength (1 RM), glycaemia, insulinemia, lipid profile and inflammatory markers (C-reactive protein, interleukin-6, tumour necrosis factor-alpha, interleukin-10, leptin, resistin and adiponectin) were measured before and after intervention. There was a significant decrease in body fat (P < 0.01) and increase in fat-free mass (P < 0.01), VO_2peak (P < 0.01), 1 RM for leg press (P < 0.01) and bench press (P < 0.01) in the overweight training group. Concomitantly, this group presented significant decreases in serum concentrations of C-reactive protein (P < 0.05) and leptin (P < 0.05), as well as in insulin resistance (P < 0.05) after the experimental period. In conclusion, 12 weeks of combined training without caloric restriction reduced inflammatory markers associated with obesity in overweight girls.     

One hundred and fifty years of sprint and distance running – Past trends and future prospects

Sprint and distance running have experienced remarkable performance improvements over the past century. Attempts to forecast running performances share an almost similarly long history but have relied so far on relatively short data series. Here, we compile a comprehensive set of season-best performances for eight Olympically contested running events. With this data set, we conduct (1) an exponential time series analysis and (2) a power-law experience curve analysis to quantify the rate of past performance improvements and to forecast future performances until the year 2100. We find that the sprint and distance running performances of women and men improve exponentially with time and converge at yearly rates of 4% ± 3% and 2% ± 2%, respectively, towards their asymptotic limits. Running performances can also be modelled with the experience curve approach, yielding learning rates of 3% ± 1% and 6% ± 2% for the women's and men's events, respectively. Long-term trends suggest that: (1) women will continue to run 10–20% slower than men, (2) 9.50 s over 100 m dash may only be broken at the end of this century and (3) several middle- and long-distance records may be broken within the next two to three decades. The prospects of witnessing a sub-2 hour marathon before 2100 remain inconclusive. Our results should be interpreted cautiously as forecasting human behaviour is intrinsically uncertain. The future season-best sprint and distance running performances will continue to scatter around the trends identified here and may yield unexpected improvements of standing world records.     

Theory of mind in dogs?: examining method and concept

In line with other research, Udell, Dorey, and Wynne’s (in press) finding that dogs and wolves pass on some trials of a putative theory-of-mind test and fail on others is as informative about the methods and concepts of the research as about the subjects. This commentary expands on these points. The intertrial differences in the target article demonstrate how critical the choice of cues is in experimental design; the intersubject-group differences demonstrate how life histories can interact with experimental design. Even the best-designed theory-of-mind tests have intractable logical problems. Finally, these and previous research results call for the introduction of an intermediate stage of ability, a rudimentary theory of mind, to describe subjects’ performance.     

Toward an Integrated Framework of Multiple Text Use

We introduce the Integrated Framework of Multiple Texts to understand how students use and form connections between multiple texts to accomplish personal or task goals. The Integrated Framework of Multiple Texts conceptualizes students’ multiple text use as unfolding over the course of three stages—preparation, execution, and production. In the preparation stage of the framework, individual difference factors and students’ task analysis result in learners’ adoption of a default stance, or a general orientation, toward multiple text use. During the execution stage of the framework, students engage in a variety of behavioral, cognitive, and metacognitive/regulatory strategies to develop cross-textual links and to integrate information across multiple texts. The execution stage concludes with students’ development of a variety of affective and cognitive outcomes as a consequence of text access. Finally, in the production stage of the framework, students draw on these affective and cognitive outcomes to develop external, often written products.     

Evaluation of evidence-based medicine search skills in the clinical years

The librarians of the Health Sciences Library worked with the director of the Primary Care Clerkship to reinforce the principles of Evidence-Based Medicine (EBM) searching, taught during the first two years of medical school, through an intensive workshop. The purpose of the program was to ensure that students apply EBM principles in a timely and effective manner in clinical situations. Working in teams led by a resident and librarian, students researched real cases and then evaluated the effectiveness of their approach to the problems. This paper outlines the rationale for the team approach, reviews the administration of a computer-based workshop, and discusses the evaluation process. Evaluation focused on both the current workshop and its implications for the informatics program presented to students during years one and two.