Physiological demands of downhill mountain biking

Abstract

Mountain biking is a popular recreational pursuit and the physiological demands of cross-country style riding have been well documented. However, little is known regarding the growing discipline of gravity-assisted downhill cycling. We characterised the physiological demands of downhill mountain biking under typical riding conditions. Riding oxygen consumption ([Vdot]O₂) and heart rate (HR) were measured on 11 male and eight female experienced downhill cyclists and compared with data during a standardised incremental to maximum ([Vdot]O_2max) exercise test. The mean [Vdot]O₂ while riding was 23.1 ± 6.9 ml · kg^?1 · min^?1 or 52 ± 14% of [Vdot]O_2max with corresponding heart rates of 146 ± 11 bpm (80 ± 6% HRmax). Over 65% of the ride was in a zone at or above an intensity level associated with improvements in health-related fitness. However, the participants’ heart rates and ratings of perceived exertion were artificially inflated in comparison with the actual metabolic demands of the downhill ride. Substantial muscular fatigue was evident in grip strength, which decreased 5.4 ± 9.4 kg (5.5 ± 11.2%, P = 0.03) post-ride. Participation in downhill mountain biking is associated with significant physiological demands, which are in a range associated with beneficial effects on health-related fitness.     

State anxiety and motor performance: Testing the conscious processing hypothesis

Previous research has argued that skills acquired explicitly are more likely to fail under stressful conditions than skills that have been learned implicitly.The present study addressed an alternative explanation for the robustness under stress of implicit task performance. As implicit learners acquired the skill of golf putting while generating random letters, it is possible that they became desensitized to self-generated verbalizations and thus immune to the effects of competitive anxiety. We tested this interpretation while controlling for a further rival hypothesis generated by Eysenck's Processing Efficiency Theory. Wealso examined the effect of increased state anxiety on the kinematic processes underlying performance breakdowns. For task performance, we found evidence that partially supported the conscious processing hypothesis, while the results of the kinematic analysis of the putting stroke were equivocal. Analysis of self-reported effort scores provided partial support for processing efficiency theory.     

The effects of anxiety upon psychomotor performance

This paper describes an experiment which examined the effects of anxiety on choice reaction time and movement time. A balanced repeated measures design was adopted in which eight female subjects performed a six‐choice visual reaction task in ‘no anxiety’ and ‘anxiety’ conditions. The anxiety condition required subjects to jump from a balcony 15 feet (4.57 m) into a foam‐filled pit below. Subjects in the anxiety condition demonstrated significantly higher levels of cognitive anxiety and longer reaction times than those in the no anxiety condition. The analysis of the reaction time data also revealed a significant interaction between anxiety and block. No significant effects emerged in the case of movement time.     

Exploring self-talk and affective states in sport

In this study, we examined (1) the relationship between self-talk and affect and (2) the nature of motivating self-talk. Ninety high-school athletes completed the Affect Grid and the Self-Talk Grid before practice and competition. Significant positive second-order partial correlations of low to moderate strength offered support for a relationship between self-talk and affect. In addition, significant positive second-order partial correlations of moderate strength were found for a relationship between negative-positive self-talk and demotivating-motivating self-talk. An examination of scatter plots indicated that some athletes rated their self-talk as negative as well as being motivational. These findings lend support to the suggestion that negative self-talk may motivate some athletes.     

Increased shoe bending stiffness increases sprint performance

The purposes of this investigation were to determine if increasing the bending stiffness of sprint shoes increases sprinting performance and to determine whether simple anthropometric factors can be used to predict shoe bending stiffness for optimal performance. Thirty-four athletes were tested using four different shoe conditions--a standard condition consisting of their currently used footwear and three conditions where the bending stiffness was increased systematically. The sprinters performed maximal effort 40 m sprints and their sprint times were recorded from 20 to 40 m. On average, increasing the shoe bending stiffness increased sprint performance. The stiffness each athlete required for his or her maximal performance was subject specific but was not related to subject mass, height, shoe size or skill level. It is speculated that individual differences in the force-length and force-velocity relationships of the calf muscles may influence the appropriate shoe stiffness for each athlete to obtain their maximal performance.     

Quantifying athlete self-talk

Two studies were conducted. The aims of Study 1 were (a) to generate quantitative data on the content of athletes' self-talk and (b) to examine differences in the use of self-talk in general as well as the functions of self-talk in practice and competition settings. Differences in self-talk between the sexes, sport types and skill levels were also assessed. Athletes (n = 295, mean age = 21.9 years) from a variety of sports and competitive levels completed the Self-Talk Use Questionnaire (STUQ), which was developed specifically for the study. In Study 1, single-factor between-group multivariate analyses of variance revealed significant differences across sex and sport type for the content of self-talk. Mixed-model multivariate analyses of variance revealed overall greater use of self-talk, as well as increased use of the functions of self-talk, in competition compared with practice. Moreover, individual sport athletes reported greater use of self-talk, as well as the functions of self-talk, than their team sport counterparts. In Study 2, recreational volleyball players (n = 164, mean age = 21.5 years) completed a situationally modified STUQ. The results were very similar to those of Study 1. That the content of athlete self-talk was generally positive, covert and abbreviated lends support to the application of Vygotsky's (1986) verbal self-regulation theory to the study of self-talk in sport. Researchers are encouraged to examine the effectiveness of self-talk in future studies.     

Stimulus generalization of an illness-induced aversion to different intensities of colored water in Japanese quail

After quail (Coturnix coturnix japonica) experienced a toxicosis following ingestion of water colored dark blue or light blue, the stimulus generalization of the aversion to light, medium, and dark blue water was investigated. Birds made ill following ingestion of dark blue water demonstrated a reduced aversion when tested with intensities of blue water weaker than the conditioning intensity. Birds made ill following ingestion of light blue water showed stronger aversions as a function of increasing test intensity, suggesting a stimulus intensity dynamism effect. The stimulus generalization and stimulus-intensity dynamism effects observed in this study where visual cues were used is in agreement with other results within the illness-induced aversions paradigm where rats were tested with varying concentrations of a gustatory stimulus.