Potentiation of sprint cycling performance: the effects of a high-inertia ergometer warm-up

ABSTRACT

Participant and protocol factors affect post-activation potentiation response. Performance enhancement is more consistent in highly-trained participants following multiple sets of a biomechanically similar conditioning activity. Providing optimal conditions, 6 international-level sprint cyclists executed multiple sets of short maximal conditioning contractions on a high-inertia ergometer before metered sprint performance. Three trial conditions were completed on separate days after a standardised warm-up: dynamic (DYN: 4 × 4 crank-cycles), isometric (ISO: 4 × 5-sec maximal voluntary contraction (MVC)), and control (CON: rest). Performance was measured from standing start to maximum velocity on an inertial-load ergometer at baseline (Pre), 4 (Post4), 8 (Post8) and 16 (Post16) min post-conditioning. Performance and biomechanical measures were assessed across 4 sprint segments, with magnitude-based inferences used to assess the likelihood that any affect was beneficial. Performance time only improved in DYN Post4, a 3.9% reduction during the first crank cycle (92% likely). On the ascending limb of the power-cadence relationship, peak torque and average power increased by 6.2% (94% likely) and 4.0% (87% likely), respectively. In ISOPost16, optimal cadence increased (82% likely) and average power improved over the descending limb (76% likely). DYN and ISO potentiated extremities of the torque-cadence relationship at distinct recovery times post-conditioning. This study suggests merit in including a high-inertia warm-up for sprint cycling.     

Changes in the perception of action possibilities while climbing to fatigue on a climbing wall

In two experiments we examined changes in the perception of action possibilities as a function of exertion. In Experiment 1, participants repeatedly climbed on a climbing wall in a series of trials that progressively increased in number to 10 trials, resulting in increased exertion. Before and during climbing, the participants judged their maximum reaching height and perceived exertion. On a separate day, participants climbed another 10 trials while performing actual maximum reaches. Higher perceived exertion was associated with decreases in perceived maximum reach while the actual reaches did not decrease. However, the perceptual changes occurred early during task execution when the participants were not yet fatigued. When exertion set in, neither perceived nor actual maximum reaching appeared to be affected. In Experiment 2, we included exhaustion trials. The findings replicated the early changes in perception observed in Experiment 1, which may be explained by hands-on experience with the task. Furthermore, while climbing to exhaustion, perceptual judgements largely changed in keeping with changes in the actual maximum reach. Thus, there appeared to be a functional relationship between participants' actual action capabilities, rather than their state of physical fatigue per se, and perceived action possibilities.     

The influence of surface and deep cues on primary and secondary school students' assessment of relevance in Web menus

Two experiments investigated primary and secondary school students' Web menu selection strategies using simulated Web search tasks. It was hypothesized that students' selections of websites depend on their perception and integration of multiple relevance cues. More specifically, students should be able to disentangle superficial cues (e.g., keywords and typographical emphasis) from deep semantic cues. Experiment 1 found that 5th and 7th graders' selections were strongly influenced by superficial relevance cues. The influence of superficial cues decreased in 9th and 12th graders. Experiment 2 examined the influence of prior elaboration of the search topic on 5th and 7th graders' website selection. Reading a short text about the search topic prior to selecting websites increased good readers' selection of relevant websites. Poor readers' selection performance was lower and unaffected by the task context manipulation. The results are discussed in terms of students' acquisition of flexible reading skills that include an awareness of the contextual demands. Implications for the use of Web-based tasks in instructional settings are considered.     

Letter to the editor

Santos-Concejero and Tucker argued in their letter to the editor that in our study the running economy in achieving superior performance was overlooked due to some methodological aspects. Having given the remarks of Santos-Concejero and Tucker appropriate consideration, in this letter to the editor, we argue that our paper does not downplay the influence of running economy on the determinants of the East African running phenomenon, but rather adds novel insights into the interaction between running economy, maximal oxygen uptake and performance.     

Does Religious Education as an examination subject work to promote community cohesion? An empirical enquiry among 14- to 15-year-old adolescents in England and Wales

This study begins by examining the way in which, in both England and Wales, Religious Education has become implicated in political discussion regarding the role of education in promoting community cohesion. The relationship between taking Religious Education as an examination subject and attitude towards religious diversity (as an affective indicator of community cohesion) is then explored among 3052 14- to 15-year-old students. After controlling for contextual factors (school type and geographical location), personal factors (sex and age), psychological factors (psychoticism, neuroticism and extraversion) and religious factors (Christian affiliation, worship attendance, personal prayer and belief in God), a small but significant positive association was found between taking Religious Education as an examination subject and attitude towards religious diversity. This finding may be interpreted as supporting the view that Religious Education works to promote community cohesion, although the wider debate that the community cohesion agenda has generated among religious educators needs further exploration.     

Dependency-aware unequal erasure protection codes

Classical unequal erasure protection schemes split data to be protected into classes which are encoded independently. The unequal protection scheme presented in this paper is based on an erasure code which encodes all the data together according to the existing dependencies. A simple algorithm generates dynamically the generator matrix of the erasure code according to the packets streams structure, i.e., the dependencies between the packets, and the rate of the code. This proposed erasure code was applied to a packetized MPEG4 stream transmitted over a packet erasure channel and compared with other classical protection schemes in terms of PSNR and MOS. It is shown that the proposed code allows keeping a high video quality-level in a larger packet loss rate range than the other protection schemes.