Biomechanics,energetics and coordination during extreme swimming intensity: effect of performance level

The present study aimed to examine how high- and low-speed swimmers organise biomechanical, energetic and coordinative factors throughout extreme intensity swim. Sixteen swimmers (eight high- and eight low-speed) performed, in free condition, 100-m front crawl at maximal intensity and 25, 50 and 75-m bouts (at same pace as the previous 100-m), and 100-m maximal front crawl on the measuring active drag system (MAD-system). A 3D dual-media optoelectronic system was used to assess speed, stroke frequency, stroke length, propelling efficiency and index of coordination (IdC), with power assessed by MAD-system and energy cost by quantifying oxygen consumption plus blood lactate. Both groups presented a similar profile in speed, power output, stroke frequency, stroke length, propelling efficiency and energy cost along the effort, while a distinct coordination profile was observed (F_{(3, 42)} = 3.59, P = 0.04). Speed, power, stroke frequency and propelling efficiency (not significant, only a tendency) were higher in high-speed swimmers, while stroke length and energy cost were similar between groups. Performing at extreme intensity led better level swimmers to achieve superior speed due to higher power and propelling efficiency, with consequent ability to swim at higher stroke frequencies. This imposes specific constraints, resulting in a distinct IdC magnitude and profile between groups.     

The location of the tibial accelerometer does influence impact acceleration parameters during running

Tibial accelerations have been associated with a number of running injuries. However, studies attaching the tibial accelerometer on the proximal section are as numerous as those attaching the accelerometer on the distal section. This study aimed to investigate whether accelerometer location influences acceleration parameters commonly reported in running literature. To fulfil this purpose, 30 athletes ran at 2.22, 2.78 and 3.33 m · s^–1 with three accelerometers attached with double-sided tape and tightened to the participants’ tolerance on the forehead, the proximal section of the tibia and the distal section of the tibia. Time-domain (peak acceleration, shock attenuation) and frequency-domain parameters (peak frequency, peak power, signal magnitude and shock attenuation in both the low and high frequency ranges) were calculated for each of the tibial locations. The distal accelerometer registered greater tibial acceleration peak and shock attenuation compared to the proximal accelerometer. With respect to the frequency-domain analysis, the distal accelerometer provided greater values of all the low-frequency parameters, whereas no difference was observed for the high-frequency parameters. These findings suggest that the location of the tibial accelerometer does influence the acceleration signal parameters, and thus, researchers should carefully consider the location they choose to place the accelerometer so that equivalent comparisons across studies can be made.     

Body dissatisfaction in women’s artistic gymnastics: A longitudinal study of psychosocial indicators

Body dissatisfaction is prevalent in women’s artistic gymnastics (WAG). Cross-sectional research points to social and individual risk factors, however it does not account for potential changes in body dissatisfaction during an athletic season. This study aimed to determine how gymnasts’ body dissatisfaction, risk factors for eating disorders, media internalisation, perfectionism and mood state change during pre-competition, competition and post-competition seasons and to identify how these psychosocial indicators impact on body dissatisfaction during the athletic year. The sample consisted of 20 Brazilian elite women’s artistic gymnasts aged 10–16 years. Data were obtained from a 9-month study using: Body Shape Questionnaire (BSQ); Eating Attitude Test-26; Sociocultural Attitudes Towards Appearance Questionnaire-3 (SATAQ-3); Multidimensional Perfectionism Scale (MPS); Brunel Mood Scale (BRUMS) and triceps and subscapular skinfolds. Body dissatisfaction was higher during the competition season and disordered eating, perfectionism and vigour values were higher in the pre-competition season. Disordered eating has been found as the strongest predictor of body dissatisfaction during all seasons, and mood state partly contributed to body dissatisfaction in the competitive season. Stakeholders should understand that body dissatisfaction and the prevalence of disordered eating may change over time.     

Associations of physical activity,sedentary time,and physical fitness with mental health during pregnancy: The GESTAFIT project

PurposeThis study was aimed to analyze the associations of objectively measured physical activity (PA), sedentary time, and physical fitness with mental health in the early second trimester (16 ± 2 gestational weeks) of pregnancy.MethodsFrom 229 women initially contacted, 124 pregnant women participated in the present cross-sectional study. Data were collected between November 2015 and March 2017. The participants wore Actigraph GT3X+ Triaxial accelerometers for 9 consecutive days to objectively measure their PA levels and sedentary time. A performance-based test battery was used to measure physical fitness. Self-report questionnaires assessed psychological ill-being (i.e., negative affect, anxiety, and depression), and psychological well-being (i.e., emotional intelligence, resilience, and positive affect). Linear regression analyses were adjusted for age, educational level, accelerometer wear time, miscarriages, and low back pain.ResultsModerate-to-vigorous PA was negatively associated with depression (β = –0.222, adjusted R² = 0.050, p = 0.041). Higher levels of sedentary time were negatively associated with positive affect (β = –0.260, adjusted R² = 0.085, p = 0.017). Greater upper-body flexibility was positively associated with better emotional regulation (β = 0.195, adjusted R²= 0.030, p = 0.047). The remaining associations were not significant (all p > 0.05).ConclusionAn active lifestyle characterized by higher levels of moderate-to-vigorous PA and lower levels of sedentary time during pregnancy might modestly improve the mental health of pregnant women. Although previous research has focused on the benefits of cardiorespiratory exercise, the present study shows that only upper-body flexibility is related to emotional regulation in early pregnant women. If the present findings are corroborated in further experimental research, physical exercise programs should focus on enhancing flexibility to promote improvements in emotional regulation during early second-trimester of pregnancy.     

Comparison of different theoretical models estimating peak power output and maximal oxygen uptake in trained and elite triathletes and endurance cyclists in the velodrome

The aim of this study was to assess which of the equations that estimate peak power output and maximal oxygen uptake (VO2max) in the velodrome adapt best to the measurements made by reference systems. Thirty-four endurance cyclists and triathletes performed one incremental test in the laboratory and two tests in the velodrome. Maximal oxygen uptake and peak power output were measured with an indirect calorimetry system in the laboratory and with the SRM training system in the velodrome. The peak power output and VO2max of the field test were estimated by means of different equations. The agreement between the estimated and the reference values was assessed with the Bland-Altman method. The equation of Olds et al. (1995) showed the best agreement with respect to the peak power output reference values, and that of McCole et al. (1990) was the only equation to show good agreement with respect to the VO2max reference values. The VO2max values showed a higher coefficient of determination with respect to maximal aerobic speed when they were expressed in relative terms. In conclusion, the equations of Olds et al. (1995) and McCole et al. (1990) were best at estimating peak power output and VO2max in the velodrome, respectively.     

Overall indexes of coordination in front crawl swimming

ABSTRACT

The aim of this study was to propose a group of parameters able to quantify not only arm coordination but also inter limb coordination. These include the well know index of coordination with the relative duration of the stroke phases and two new parameters: the Index of synchronization (Ids) between arms and legs actions; and the Index of inter limb coordination (IdIC) calculated as the relative foot position during successive arm stroke phases. These parameters were compared between experts and amateur swimmers in a maximal front crawl sprint. The influence of arm stroke in leg kick parameters was also assessed, comparing the full stroke condition with a condition without arms actions. Sixty-five per cent of expert swimmers used synchronized limb actions while 95% of amateur swimmers used non-synchronized limb motions. These synchronized expert swimmers also converged towards a specific coordination pattern between foot position and arm stroke phases. In the condition without arms, both groups changed kick rate and amplitude. The present study reveals the interdependency of arms and legs actions and the importance of coordination and synchronization between limbs. Therefore, the proposed group of overall indexes of coordination provides a more complete marker for the analysis of swimming technique.     

Individual Differences in Categorical Perception Are Related to Sublexical/Phonological Processing in Reading

This article examines the relationship between individual differences in speech perception and sublexical/phonological processing in reading. We used an auditory phoneme identification task in which a?/ba/-/pa/?syllable continuum measured sensitivity to classify participants into three performance groups: poor, medium, and good categorizers. A lexical decision task manipulated syllable and word frequency. We found that the two tasks were associated. Poor categorizers did not present the typical syllable frequency effect; however, the other groups were sensitive to phonological information to differing degrees and showed the inhibitory syllable frequency effect only for low-frequency words. These results suggest that auditory phoneme identification efficiency may be related to the sublexical processes involved in reading words.     

Routine leisure activities: opportunity and risk in adolescence / Rutinas de tiempo libre: oportunidad y riesgo en la adolescencia

Abstract

In order to differentiate between types of routine leisure activities and to evaluate their corresponding protection/risk value in adolescent development, we performed a study with a sample of 218 adolescents between the ages of 12 and 14 years by asking them to fill out a grid that analysed their daily routines. The results are presented here. They were required to account for each hour of a weekday by specifying whether they were awake or asleep, the place they were at, who they were with, and what type of activity they were engaged in. A group of these adolescents (N = 59) were considered to be at risk (they formed part of a social integration and marginalization prevention program), whereas the rest (comparison group) were their classmates. A multiple correspondence analysis was performed, revealing the existence of four adolescent typologies according to daily routines. The analysis showed that the routines incorporating a greater variety of leisure activities, as well as more creative, organized, and supervised activities, were associated with adolescents who possessed a more normative development, whereas more monotonous, unstructured and unsupervised activities tended to be characteristic of adolescent development at risk.