The Effect of Secret Clock Manipulation on 10 km Cycle Time Trial Performance.

The anticipatory RPE feedback model (Tucker 2009) proposes that during self paced exercise tasks, muscular work is continually regulated through comparison of a subconscious ‘template’ Rating of Perceived Exertion (RPE) that serves to protect against the development of catastrophic physiological failure, and a ‘conscious’ RPE that is generated through afferent feedback with regards to peripheral physiological status and through psychological inputs. The aim of this study was to investigate the effect of altering psychological inputs via incorrect time feedback on both RPE and performance during a series of maximal effort 10km cycle time trials. After task familiarisation, eight participants performed three separate time trials using their own cycle mounted onto the Kingcycle ergometer rig. Distance covered was available via large visual display along with elapsed time. On one occasion the display clock ran at the correct speed, but on two other occasions the clock manipulation was altered so that it ran either 10% too fast or 10% too slow. The order of the interventions was randomised. Although no significant differences were observed in total performance time, the magnitude of the endspurt participants were able to generate in the final 10% of the trial was significantly (P<0.01) greater during the slow clock trials than during the fast clock trials. Despite differences in pace distribution under each clock condition, a similar generally linear increase in RPE was observed throughout trials in all conditions. It is proposed that these findings lend support to the anticipatory RPE feedback model, and that altered psychological inputs probably act by influencing the fraction of metabolic reserve capacity that can be accessed during such trials

Influence of Different Performance Levels on Pacing Strategy During the Women's World Championship Marathon Race.

Purpose To analyse pacing strategies displayed by athletes achieving differing levels of performance during an elite level marathon race. Methods Competitors in the 2009 IAAF Women’s Marathon Championship were split into Groups 1, 2, 3, and 4 comprising the first, second, third, and fourth 25% of finishers respectively. Final, intermediate, and personal best (PB) times of finishers were converted to mean speeds, and relative speed (% of PB speed) was calculated for intermediate segments. Results Mean PB speed decreased from Group 1 to 4 and speed maintained in the race was 98.5 + 1.8%, 97.4 + 3.2%, 95.0 + 3.1% and 92.4 + 4.4% of PB speed for Groups 1-4 respectively. Group 1 was fastest in all segments and differences in speed between groups increased throughout the race. Group 1 ran at lower relative speeds than other groups for the first two 5 km segments, but higher relative speeds after 35km. Significant differences (P<0.01) in the percentage of PB speed maintained were observed between Groups 1 and 4, and 2 and 4 in all segments after 20 km, and Groups 3 and 4 from 20-25 km and 30-35 km. Conclusions Group 1 athletes achieved superior finishing times relative to their PB than athletes in other Groups who selected unsustainable initial speeds resulting in subsequent significant losses of speed. It is suggested that psychological factors specific to a major competitive event influenced decision making by athletes and poor decisions resulted in final performances inferior to those expected based on PB times

All for One and One for All! Disparity Between Overall Crew’s and Individual Rowers’ Pacing Strategies During Rowing

Purpose: This study examined individual contributions to overall pacing strategy during 2- and 5-km rowing trials in a cox-less-4 boat. Methods: A crew of 4 male rowers performed maximal-effort on-water trials over 2 and 5 km, and power output during every individual stroke was measured for each crew member. Mean overall boat and individual rower stroke power were calculated for each 25% epoch (25% of total strokes taken), and power for each individual epoch was calculated as a percentage of mean power maintained over the entire distance. The coefficient of variation was used to determine stroke-to-stroke and epoch-to-epoch variability for individual rowers and the overall boat. Results: In both trials, the overall pacing strategy consisted of a high power output in the initial 25% that decreased in the middle 50% and increased again in the final 25%. However, individual rower data indicate wide variation in individual power profiles that did not always mimic the overall boat profile. Conclusions: This study demonstrates that overall boat power profiles during 2- and 5-km rowing trials are similar to velocity profiles previously reported for individual ergometry and on-water racing events. However, this over-all profile is achieved despite considerable variation in individual rower profiles. Further research is warranted to determine the mechanisms through which individual contributions to overall pacing strategy are regulated and the effectiveness or oth-erwise of seemingly disparate individual strategies on overall performance

Tangibly Reducing Sedentariness in Office Workers

It is claimed sedentariness is as much a threat to long- term health as smoking or unhealthy eating, and is not mitigated by bursts of physical activity. Desk bound office workers are particularly vulnerable to this risk, given the inherently sedentary nature of their roles. To tackle this problem in HCI, we have focused largely on smartphones apps whilst embracing a general trend towards automating data collection of behavior. We argue that placing technologies in the environment, leveraging ambient displays and Tangible User Interfaces (TUIs), can offer a more effective approach for tackling sedentary behaviors in an office environment. We include a brief design of a device we intend to use to evaluate these ideas

A Computer Model of Drafting Effects on Collective Behavior in Elite 10,000 m Runners

Purpose Drafting in cycling influences collective behaviour of pelotons. Whilst evidence for collective behaviour in competitive running events exists, it is not clear if this results from energetic savings conferred by drafting. This study modelled the effects of drafting on behavior in elite 10,000 m runners. Methods Using performance data from a men’s elite 10,000 m track running event, computer simulations were constructed using Netlogo 5.1 to test the effects of three different drafting quantities on collective behaviour: no drafting, drafting to 3m behind with up to ~8% energy savings (a realistic running draft); and drafting up to 3m behind with up to 38% energy savings (a realistic cycling draft). Three measures of collective behaviour were analysed in each condition; mean speed, mean group stretch (distance between first and last placed runner), and Runner Convergence Ratio (RCR) which represents the degree of drafting benefit obtained by the follower in a pair of coupled runners. Results Mean speeds were 6.32±0.28m.s-1, 5.57±0.18 m.s-1, and 5.51±0.13 m.s-1 in the cycling draft, runner draft, and no draft conditions respectively (all P<0.001). RCR was lower in the cycling draft condition, but did not differ between the other two. Mean stretch did not differ between conditions. Conclusions Collective behaviours observed in running events cannot be fully explained through energetic savings conferred by realistic drafting benefits. They may therefore result from other, possibly psychological, processes. The benefits or otherwise of engaging in such behavior are, as yet, unclear

Phonological priming and phonetic carry-over in two Danish-English bilinguals

In this study we investigate whether the phonetic carry-over effects (or gestural drift) reported in the literature as occurring in the speech of bilinguals after long-term phonological priming (i.e., several months), also occur after short-term priming of less than all hour. Two bilingual Danish-English speakers were asked to read word lists after being primed for some time in one or other of their languages. In the Danish mode, a number of switches into English occurred in the word-list, and in the English mode switches into Danish were included. The switches allowed the examination of three possible carry-over effects: two with vowels and one with consonants. The results demonstrated no effect with the switches that would require the greatest phonetic change. They also showed that some potential carry-over effects were more likely long-term interference pattems. Acoustic aualysis did suggest that with one of the vowel switches carry-over effects going both ways between Danish and English and English and Danish did occur, although this was clearer with one subject than the other

Different Psychophysiological Responses to a High-intensity Repetition Session Performed Alone or in a Group by Elite Middle-distance Runners

Internal training load refers to the degree of disturbance in psychophysiological homeostasis provoked by a training session and has been traditionally measured through session-RPE, which is the product of the session Rate of Perceived Exertion (RPE) and the duration. External training load refers to the actual physical work completed, and depends on session volume, intensity, frequency and density. Drafting, which is achieved by running closely behind another runner has been demonstrated to reduce the energy cost of running at a fixed speed and to improve performance. Therefore, it is hypothesized that psychophysiological responses might reflect different levels of internal load if training is performed individually or collectively. 16 elite middle-distance runners performed two high-intensity training sessions consisting of 4 repetitions of 500 m separated by 3 minutes of active recovery. Sessions were performed individually and collectively. Times for each repetition, RPE, core affect (valence and felt arousal) and blood lactate concentrations [BLa] were measured after each repetition. Main time effect was significant and increased across repetitions for [BLa] and RPE (p <0.001), and decreased for valence (p =0.001). Main group effect was significant and values were higher when training individually for [BLa] (p =0.003) and RPE (p =0.001), and lower for valence (p =0.001). No differential responses were found between conditions in terms of repeat time or felt arousal. Findings demonstrate that elite middle-distance athletes running collectively display lower levels of internal training load compared to running alone, despite external training load being similar

Athletic Races Represent Complex Systems, and Pacing Behavior Should Be Viewed as an Emergent Phenomenon

Pacing is the manner in which effort is distributed over the duration of an exercise bout, and is an important determinant of the extent to which individual potential is realized during athletic races. Observed pacing behaviors are thought to result from complex decision-making processes, and several models have been proposed that may explain the manner in which these decisions are made. In this article we argue that examination of individual factors implicated in the regulation of pacing is unlikely to allow full understanding of the events leading to pacing and performance. Rather than utilizing such a reductionist approach, it is suggested that athletic races be viewed as complex systems, and that pacing behavior is an emergent phenomenon that cannot be fully understood through study of components of the system in isolation. We describe and discuss known and potential interactions between determinants of pacing during races, and conclude with a call for the development of novel research methodologies that may further understanding of the manner in which observed behaviors emerge

The Influence of Performance Level, Age and Gender on Pacing Strategy During a 100-km Ultramarathon

The aim of this study is to analyse the influence of performance level, age and gender on pacing during a 100-km ultramarathon. Results of a 100-km race incorporating the World Masters Championships were used to identify differences in relative speeds in each 10-km segment between participants finishing in the first, second, third and fourth quartiles of overall positions (Groups 1, 2, 3 and 4, respectively). Similar analyses were performed between the top and bottom 50% of finishers in each age category, as well as within male and female categories. Pacing varied between athletes achieving different absolute performance levels. Group 1 ran at significantly lower relative speeds than all other groups in the first three 10-km segments (all P < 0.01), and significantly higher relative speeds than Group 4 in the 6th and 10th (both P < 0.01), and Group 2 in the 8th (P = 0.04). Group 4 displayed significantly higher relative speeds than Group 2 and 3 in the first three segments (all P < 0.01). Overall strategies remained consistent across age categories, although a similar phenomenon was observed within each category whereby ‘top’ competitors displayed lower relative speeds than ‘bottom’ competitors in the early stages, but higher relative speeds in the later stages. Females showed lower relative starting speeds and higher finishing speeds than males. ‘Top’ and ‘bottom’ finishing males displayed differing strategies, but this was not the case within females. Although pacing remained consistent across age categories, it differed with level of performance within each, possibly suggesting strategies are anchored on direct competitors. Strategy differs between genders and differs depending on performance level achieved in males but not females