Does acute exercise switch off switch costs? A study with younger and older athletes

This study investigated the effects of acute exercise on 53 young (16-24 years) and 47 older (65-74 years) adults' switch-task performance. Participants practiced sports requiring either low or high cognitive demands. Both at rest and during aerobic exercise, the participants performed two reaction time tasks that differed in the amount of executive control involved in switching between global and local target features of visual compound stimuli. Switch costs were computed as reaction time differences between switch and nonswitch trials. In the low demanding task, switch costs were sensitive only to age, whereas in the high demanding task, they were sensitive to acute exercise, age, and sport-related cognitive expertise. The results suggest that acute exercise enhances cognitive flexibility and facilitates complex switch-task performance. Both young age and habitual practice of cognitively challenging sports are associated with smaller switch costs, but neither age nor cognitive expertise seem to moderate the relationship between acute exercise and switch-task performance.     

Is starting with the feet out of the water faster in backstroke swimming?

This study aimed to determine if starting with the feet above the water (FAW) in male backstroke swimming resulted in faster start times (15-m time) than when the feet were underwater (FUW). It was hypothesised that setting higher on the wall would generate increased horizontal force and velocity, resulting in quicker starts. Twelve high-level male backstrokers performed three trials of the FAW and FUW techniques. A biomechanical swimming testing system comprising one force plate (1,000 Hz), four lateral-view (100 Hz), and five overhead (50 Hz) video cameras captured the swimmers' performance. Data for each participant's fastest trial for each technique were collated, grouped, and statistically analysed. Analysis included Wilcoxon, Spearman Rho correlation, and regression analysis. Wilcoxon results revealed a significantly faster start time for the FAW technique (p < 0.01). Peak horizontal force was significantly smaller for FAW (p = 0.02), while take-off horizontal velocity was significantly greater (p = 0.01). Regression analysis indicated take-off horizontal velocity to be a good predictor of start time for both techniques, and the horizontal displacement of the centre of mass for the FAW start.     

Are athletes on the right track? The effect of availability of an all-weather athletics track on athletics performance

In February of 2011, an earthquake destroyed the only all-weather athletics facility in the city of Christchurch, New Zealand. The all-weather track has yet to be replaced, and so since the loss of the track, local Christchurch athletes have only had a grass track for training and preparation for championship events. The present study considers what effect the loss of the training facility has had on the performance of athletes from Christchurch at national championship events. Not surprisingly, the study finds that there has been a deterioration in the performance in events that are heavily dependent upon the all-weather surface. However, somewhat more surprisingly, the loss of the track appears to have caused a significant improvement in the performance of Christchurch athletes in events that, while on the standard athletics programme, are not heavily dependent on track surface.     

Do weight categories prevent athletes from relative age effect?

Abstract

The aim of this study was to investigate whether weight categories prevent young athletes from being exposed to a relative age effect. The dates of birth of all French female (n = 727) and male (n = 5440) amateur boxers who participated in the 2010–2011 season were collected from the federation database. The dates of birth of all French male professional boxers (n = 354) were also collected. The results show an absence of a relative age effect among French female and male amateur boxers. The results also show an absence of this phenomenon among French male professional boxers. The male 18–18+ age category reveal an inverse relative age effect. This inverse relative age effect might be interpreted as the result of a strategic adaptation from relatively younger children who shift from one sport to another where there are weight categories in order to ensure fair competition. The results of this study suggest that the weight category system is a possible solution within the relative age effect phenomenon.     

Can losing teams cope with destructive voice behaviour? The role of game results and athletes’ perceived motivational climate

This study examined the relation between losing a game and players’ destructive voice about the coach. As team performances would suffer when such behaviours are not managed properly, we tested the motivational climate as a potential mechanism by which coaches can manage these destructive behaviours. Twelve volleyball and basketball teams (N = 136) were weekly assessed during eight weeks using questionnaires. Players rated the extent to which their teammates expressed destructive voice about their coach. Each player’s indegree centrality (i.e. the average score received from all teammates) functioned as measurement of his/her destructive voice about the coach. As hypothesized, losing a game increased players’ expression of destructive voice about the coach. At both the within- and between-person level, perceived mastery (performance) climate negatively (positively) predicted players’ destructive voice about the coach. When players perceived a more salient performance climate than usual after a loss, their increase in destructive voice about the coach was magnified. These results highlight the dynamics of players’ destructive voice about the coach and how a single loss can start the utterance of such voice. A coach would be able to counter this process by increasing the focus on a mastery rather than a performance climate.     

How does visual manipulation affect obstacle avoidance strategies used by athletes?

Research examining our ability to avoid obstacles in our path has stressed the importance of visual input. The aim of this study was to determine if athletes playing varsity-level field sports, who rely on visual input to guide motor behaviour, are more able to guide their foot over obstacles compared to recreational individuals. While wearing kinematic markers, eight varsity athletes and eight age-matched controls (aged 18–25) walked along a walkway and stepped over stationary obstacles (180° motion arc). Visual input was manipulated using PLATO visual goggles three or two steps pre-obstacle crossing and compared to trials where vision was given throughout. A main effect between groups for peak trail toe elevation was shown with greater values generated by the controls for all crossing conditions during full vision trials only. This may be interpreted as athletes not perceiving this obstacle as an increased threat to their postural stability. Collectively, findings suggest the athletic group is able to transfer their abilities to non-specific conditions during full vision trials; however, varsity-level athletes were equally reliant on visual cues for these visually guided stepping tasks as their performance was similar to the controls when vision is removed.     

Striving for success or addiction? Exercise dependence among elite Australian athletes

Exercise dependence is a condition that involves a preoccupation and involvement with training and exercise, and has serious health and performance consequences for athletes. We examined the validity of a biopsychosocial model to explain the development and maintenance of exercise dependence among elite Australian athletes. Participants were 234 elite Australian athletes recruited from institutes and academies of sport. Thirty-four percent of elite athletes were classified as having exercise dependence based on high scores on the measure of exercise dependence. These athletes had a higher body mass index, and more extreme and maladaptive exercise beliefs compared to non-dependent athletes. They also reported higher pressure from coaches and teammates, and lower social support, compared to athletes who were not exercise dependent. These results support the utility of a biopsychosocial model of exercise dependence in understanding the aetiology of exercise dependence among elite athletes. Limitations of the study and future research directions are highlighted.     

Are habitual runners physically inactive?

The World Health Organisation’s (WHO) physical activity guidelines recommend 150min/week of moderate- to vigorous-intensity physical activity (MVPA) accumulated in 10 min bouts. To see whether people performing habitual exercise for recreation meet these guidelines, 25 long-distance runners [mean 67 km/wk], 25 joggers [mean 28 km/wk], and 20 sedentary adults wore an ActiGraph GT3X+ accelerometer for 7 days. Sedentary time and bouts were similar in runners and sedentary adults (p > 0.46). Sedentary adults performed 20 ± 16 min/day of MVPA (usual bout duration (W50%): 9.53 ± 3.45min), with joggers and runners performing 45 ± 31min (W50%: 16.92 ± 9.53min) and 83 ± 58min (W50%: 20.35 ± 8.85min), respectively (p ≤ 0.001 versus sedentary group). Data showed that 65% of the sedentary group, 32% of joggers and 4% of long-distance runners did not meet the WHO guideline for MVPA. Failure to meet the guideline was most prominent in, but not restricted to, runners who reported ≤50km running per week. Self-reported running does not ensure adults meet physical activity guidelines or offset daily sedentary behaviours. On the other hand, the sedentary group was very close in accumulating recommended bouts of MVPA in incidental activities. Future studies should assess whether modification of work and leisure physical activity would be more fruitful than encouraging recreational exercise per se in meeting physical activity guidelines.     

Antioxidant and Vitamin D supplements for athletes: sense or nonsense?

The idea that dietary supplements can improve athletic performance is popular among athletes. The use of antioxidant supplements is widespread among endurance athletes because of evidence that free radicals contribute to muscle fatigue during prolonged exercise. Furthermore, interest in vitamin D supplementation is increasing in response to studies indicating that vitamin D deficiency exists in athletic populations. This review explores the rationale for supplementation with both antioxidants and vitamin D and discusses the evidence to support and deny the benefits of these dietary supplements. The issue of whether athletes should use antioxidant supplements remains highly controversial. Nonetheless, at present there is limited scientific evidence to recommend antioxidant supplements to athletes or other physically active individuals. Therefore, athletes should consult with their health care professional and/or nutritionist when considering antioxidant supplementation. The issue of whether athletes should supplement with vitamin D is also controversial. While arguments for and against vitamin D supplementation exist, additional research is required to determine whether vitamin D supplementation is beneficial to athletes. Nevertheless, based upon the growing evidence that many athletic populations are vitamin D deficient or insufficient, it is recommended that athletes monitor their serum vitamin D concentration and consult with their health care professional and/or nutritionist to determine if they would derive health benefits from vitamin D supplementation.     

Are muscle activation patterns altered during shod and barefoot running with a forefoot footfall pattern?

This study aimed to investigate the activation of lower limb muscles during barefoot and shod running with forefoot or rearfoot footfall patterns. Nine habitually shod runners were asked to run straight for 20 m at self-selected speed. Ground reaction forces and thigh and shank muscle surface electromyographic (EMG) were recorded. EMG outcomes (EMG intensity [iEMG], latency between muscle activation and ground reaction force, latency between muscle pairs and co-activation index between muscle pairs) were compared across condition (shod and barefoot), running cycle epochs (pre-strike, strike, propulsion) and footfall (rearfoot and forefoot) by ANOVA. Condition affected iEMG at pre-strike epoch. Forefoot and rearfoot strike patterns induced different EMG activation time patterns affecting co-activation index for pairs of thigh and shank muscles. All these timing changes suggest that wearing shoes or not is less important for muscle activation than the way runners strike the foot on the ground. In conclusion, the guidance for changing external forces applied on lower limbs should be pointed to the question of rearfoot or forefoot footfall patterns.     

Singing it for “us”: Team passion displayed during national anthems is associated with subsequent success

The present research examined the link between passion displayed by team members during the singing of national anthems at UEFA Euro 2016 and team performance in the tournaments’ 51 games. Drawing on social identity theorising, we hypothesised a positive relationship between passion and performance. Consistent with this hypothesis, results showed that teams that sang national anthems with greater passion went on to concede fewer goals. Moreover, results provided evidence that the impact of passion on the likelihood of winning a game depended on the stage of the competition: in the knockout stage (but not the group stage) greater passion was associated with a greater likelihood of victory. Extending recent reviews that highlight the importance of social identity processes in sporting contexts, these results suggest that team members’ identity-based expression of passion for the collective can be an important predictor of subsequent performance.     

Are declines in physical performance associated with a reduction in skill-related performance during professional soccer match-play?

The aim of this study was to determine whether declines in physical performance in a professional soccer team during match-play were associated with reductions in skill-related performance. Computerized tracking of performance in midfield players (n = 11) showed that total distance and distance covered in high-speed running (>14.4 km · h?1) were greater in the first versus second half of games (both P < 0.001) and in the first versus the final 15 min of play (P < 0.05). Analysis of high-speed running across 5-min periods showed that more distance was covered in the first versus the final game period, and in the peak period of activity compared with the following period and game mean for other periods (all P < 0.05). Analysis of skill-related measures revealed no significant decline between halves, across 15-min intervals or in the 5-min period following that of peak high-speed activity compared with the game mean for other 5-min periods. In contrast, frequencies of passing, ball possessions, and duels were greater in the first 5-min than in the final 5-min period (P < 0.05). Neither physical nor skill-related performance was affected across three consecutive games within a period of ≤7 days. The results suggest that the players were generally able to maintain skill-related performance throughout games and when competing in successive matches within a short time.     

Are changes in running economy associated with changes in performance in runners? A systematic review and meta-analysis

Improvements in running economy (RE) are thought to lead to improvements in running performance (P). Multiple interventions have been designed with the aim of improving RE in middle and long-distance runners. The aim of this study was to assess the effect of interventions of at least 2-weeks’ duration on RE and P and to determine whether there is a relationship between changes in RE (ΔRE) and changes in running performance (ΔP). A database search was carried out in Web of Science, Scopus and SPORTDiscus. In accordance with a PRISMA checklist 10 studies reporting 12 comparisons between interventions and controls were included in the review. There was no correlation between percentage ΔRE and percentage ΔP (r = 0.46, P = 0.936, 12 comparisons). There was a low risk of reporting bias but an unclear risk of bias for other items. Meta-analyses found no statistically significant differences between interventions and controls for RE (SMD (95% CI) = ?0.37 (?1.43, 0.69), 204 participants, p = 0.49) or for P (SMD (95% CI) = ?0.65 (?26.02, 24.72, 204 participants, p = 0.99). There is a need for studies of greater statistical power, methodological quality, duration and homogeneity of intervention and population. Standardised measures of performance and greater control over non-intervention training are also required.     

Are parental concerns about children's inactivity warranted, and are they associated with a supportive home environment?

This paper explores parental concern about children's activity levels and whether parents who are concerned about their child's activity provide a supportive environment. A sample of 615 parents of 5-6-year-old children and 947 parents of 10-12-year-old children completed a questionnaire. Just over 50% of parents reported they were concerned their child was not getting enough activity. Children of concerned parents were less active than those whose parents were not concerned. These findings suggest that parents who are concerned about their child's physical activity levels provided a less supportive environment for physical activity than parents who are not concerned. The challenge for public health will be to harness parental concerns and translate them into action.     

Does self-perceived sleep reflect sleep estimated via activity monitors in professional rugby league athletes?

This study examined agreement between self-perceived sleep and sleep estimated via activity monitors in professional rugby league athletes. 63 athletes, from three separate teams wore actigraphy monitors for 10.3 ± 3.9 days. During the monitoring period, ratings of perceived sleep quality (on a 1–5 and 1–10 Likert scale), and an estimate of sleep duration were recorded daily. Agreement between sleep estimated via activity monitors and self-perceived sleep was examined using mean bias, Pearson correlation (r) and typical error of the estimate (TEE). 641 nights of sleep were recorded, with a very large, positive correlation observed between sleep duration estimated via activity monitors and subjective sleep duration (r = 0.85), and a TEE of 48 minutes. Mean bias revealed subjective sleep duration overestimated sleep by an average of 19.8 minutes. The relationship between sleep efficiency estimated via activity monitors and self-perceived sleep quality on a 1–5 (r = 0.22) and 1–10 Likert scale (r = 0.28) was limited. The outcomes of this investigation support the use of subjective measures to monitor sleep duration in rugby league athletes when objective means are unavailable. However, practitioners should be aware of the tendency of athletes to overestimate sleep duration.     

Is bioelectrical impedance spectroscopy accurate in estimating changes in fat-free mass in judo athletes?

Abstract

Bioelectrical impedance spectroscopy (BIS) provides an affordable and practical assessment of fat-free mass (FFM). However, little information is available on the assessment of changes in fat-free mass in top-level athletes using BIS. The aim of this study was to examine the accuracy of BIS in tracking changes in fat-free mass of elite male judo athletes from a period of weight stability to just before competition, using the four-compartment model (4C model) as reference method. In total, 27 elite male judo athletes (age 22.2 ± 2.8 years) were evaluated. Measures of body volume assessed by air displacement plethysmography, bone mineral content by dual-energy X-ray absorptiometry, and total-body water assessed with deuterium dilution were used in a 4C model. Fat-free mass was also assessed by BIS (FFM_BIS). Changes in FFM_BIS were not significantly different from measured by the reference method (P = 0.000). Furthermore, the r ² was 0.62 and the standard error of the estimate was 1.03 kg. The limits of agreement ranged from ?3.36 to 2.59 kg with no bias observed. These findings demonstrate the viability of BIS as a valid tool for tracking fat-free mass in elite male judo athletes. However, based on the wide limits of agreement observed, BIS is less valid at an individual level for tracking fat-free mass in these athletes.