Dietary nitrate supplementation does not improve cycling time-trial performance in the heat

This investigation examined the effect of beetroot juice (BR) supplementation, a source of dietary nitrate (NO₃^?), on cycling time-trial (TT) performance and thermoregulation in the heat. In a double-blind, repeated-measures design, 12 male cyclists (age 26.6 ± 4.4 years, VO_2peak 65.8 ± 5.5 mL.kg^?1.min^?1) completed four cycling TTs (14 kJ.kg^?1) in hot (35°C, 48% relative humidity) and euthermic (21°C, 52%) conditions, following 3 days supplementation with BR (6.5 mmol NO₃^? for 2 days and 13 mmol NO₃^? on the final day), or NO₃^–depleted placebo (PLA). Salivary NO₃^? and nitrite, core (T_c) and mean skin temperature (T_sk) were measured. Salivary NO₃^? and nitrite increased significantly post-BR supplementation (p < 0.001). Average TT completion time (mm:ss) in hot conditions was 56:50 ± 05:08 with BR, compared with 58:30 ± 04:48 with PLA (p = 0.178). In euthermic conditions, average completion time was 53:09 ± 04:35 with BR, compared with 54:01 ± 04:05 with PLA (p = 0.380). The TT performance decreased (p < 0.001), and T_c (p < 0.001) and T_sk (p < 0.001) were higher in hot compared with euthermic conditions. In summary, BR supplementation has no significant effect on cycling TT performance in the heat.     

Time–motion analysis of elite field hockey,with special reference to repeated-sprint activity

Limited information exists about the movement patterns of field-hockey players, especially during elite competition. Time–motion analysis was used to document the movement patterns during an international field-hockey game. In addition, the movement patterns of repeated-sprint activity were investigated, as repeated-sprint ability is considered to be an important fitness component of team-sport performance. Fourteen members of the Australian men's field-hockey team (age 26±3 years, body mass 76.7±5.6?kg, [Vdot]O_2max 57.9±3.6?ml?·?kg^?1?·?min^?1; mean±s) were filmed during an international game and their movement patterns were analysed. The majority of the total player game time was spent in the low-intensity motions of walking, jogging and standing (46.5±8.1, 40.5±7.0 and 7.4±0.9%, respectively). In comparison, the proportions of time spent in striding and sprinting were 4.1±1.1 and 1.5±0.6%, respectively. Our criteria for ‘repeated-sprint’ activity (defined as a minimum of three sprints, with mean recovery duration between sprints of less than 21?s) was met on 17 occasions during the game (total for all players), with a mean 4±1 sprints per bout. On average, 95% of the recovery during the repeated-sprint bouts was of an active nature. In summary, the results suggest that the motion activities of an elite field-hockey competition are similar to those of elite soccer, rugby and Australian Rules football. In addition, the investigation of repeated-sprint activity during competition has provided additional information about the unique physiological demands of elite field-hockey performance.     

The Relation of Mild Traumatic Brain Injury to Chronic Lapses of Attention

We assessed the extent to which failures in sustained attention were associated with chronic mild traumatic brain injury (mTBI) deficits in cognitive control among college-age young adults with and without a history of sport-related concussion. Participants completed the ImPACT computer-based assessment and a modified flanker task. Results indicated that a history of mTBI, relative to healthy controls, was associated with inferior overall flanker task performance with a greater number of omission errors and more frequent sequentially occurring omission errors. Accordingly, these findings suggest that failures in the ability to maintain attentional vigilance may, in part, underlie mTBI-related cognition deficits.     

Self-Controlled Amount of Practice Benefits Learning of a Motor Skill

Abstract

Self-control over factors involving task-related information (e.g., feedback) can enhance motor learning. It is unknown if these benefits extend to manipulations that do not directly affect such information. The purpose of this study was to determine if self-control over the amount of practice would also facilitate learning. Participants learned to throw a dart using their nonpreferred hand. The self-control (SC) group decided when to stop practice. The yoked group completed the same number of trials as their SC counterparts. Results revealed the SC group was more accurate during transfer and in recalling the number of trials completed. These findings indicate that self-control benefits extend to factors that do not directly alter task-related information.     

Effect of Toe Clips during Bicycle Ergometry on [Vdot]O2 max

Abstract

Previous investigators have yielded conflicting results in testing the hypothesis that the use of toe clips during bicycle ergometry produces a higher maximal oxygen uptake ([Vdot]O ₂ max) than testing without toe clips. Eight men, four competitive cyclists and four competitive distance runners volunteered to participate in three randomized [Vdot]O ₂ max tests: 1) a treadmill running lest, 2) a bicycle ergometer test using standard toe clips, and 3) a test on the same ergometer without toe clips. The highest mean [Vdot]O ₂ max was observed in the treadmill condition as expected. However, no statistically significant difference in mean [Vdot]O ₂ max or performance time was observed between the toe-clip and no toe-clip conditions. Based on these results, the research hypothesis was rejected and no favorable physiological effect may be attributed to the use of toe clips.     

Effect of sand versus grass training surfaces during an 8-week pre-season conditioning programme in team sport athletes

Abstract

This study compared the use of sand and grass training surfaces throughout an 8-week conditioning programme in well-trained female team sport athletes (n = 24). Performance testing was conducted pre- and post-training and included measures of leg strength and balance, vertical jump, agility, 20 m speed, repeat speed (8 × 20 m every 20 s), as well as running economy and maximal oxygen consumption (VO_2max). Heart rate (HR), training load (rating of perceived exertion (RPE) × duration), movement patterns and perceptual measures were monitored throughout each training session. Participants completed 2 × 1 h conditioning sessions per week on sand (SAND) or grass (GRASS) surfaces, incorporating interval training, sprint and agility drills, and small-sided games. Results showed a significantly higher (P < 0.05) HR and training load in the SAND versus GRASS group throughout each week of training, plus some moderate effect sizes to suggest lower perceptual ratings of soreness and fatigue on SAND. Significantly greater (P < 0.05) improvements in VO_2max were measured for SAND compared to GRASS. These results suggest that substituting sand for grass training surfaces throughout an 8-week conditioning programme can significantly increase the relative exercise intensity and training load, subsequently leading to superior improvements in aerobic fitness.     

The Influence of Aging on Power and Endurance in Man

Abstract

The purpose of this study was to examine the strength-decrement fatigue effects in 14 muscle groups of the trunk and lower extremities resulting from a sub-maximal treadmill run at seven miles per hour for a period of ten minutes on a horizontal plane. Only two muscle groups, the hip outward rotators and the trunk flexors, were fatigued sufficiently to cause a significant strength decrement; a third muscle group, the knee flexors, had a loss in mean strength which approached the .05 level of confidence.     

Threats to student evaluative judgement and their management

ABSTRACT

Students’ capacity for making evaluative judgements of their own work is widely acknowledged as central to their learning within programmes as well as being vital to their subsequent professional practice. In higher education literature, the act of evaluative judgement is usually portrayed as a process of deliberative, analytical reasoning requiring student agency and objectivity, typically scaffolded by points of reference such as explicit criteria, rubrics or exemplars. This article challenges this common portrayal of judgement by drawing attention to research from outside higher education on the role of unconscious factors in judgement and decision-making. Drawing from the field of heuristics and bias studies, the article outlines six unconscious factors that have the potential to distort students’ analytical judgement of their work. A recent challenge to the heuristics and bias approach that radically repositions the place of reasoning in judgement is also considered. Since these unconscious factors have received scant attention in higher education literature, the purpose of this article is to draw attention to them, to identify the challenges they pose to current understandings of evaluative judgement, and to outline their implications for enhancing assessment practice.     

Constraints to curriculum reform: Teachers and the myths of schooling

Curriculum reform efforts usually have ignored the culture in which curriculum is embedded. Principal components of the culture are the knowledge of teachers and the myths of this culture. Images, metaphors, and metonymies are forms of teacher knowledge that influence the manner in which teachers define their roles and implement the curriculum. Unless endeavors are made to facilitate teacher learning through the construction of new images, metaphors, and metonymies, it is unlikely that curricular reform will proceed in the intended manner. Similarly, the myths that define the customs and taboos of a culture need to be considered by instructional designers if their curricular resources are to be used as intended. The myths ofteacher as controller of students andobjectivism together might persuade teachers to adhere to the more traditional approach whereby knowledge is transferred to students in teacher-controlled activities.This article describes theScience Vision series, a hypermedia system developed in response to a clear need for additional resources to educate teachers concerning alternative myths and their use in relation to utilizing resources.     

Cognitive conflict: Its nature and use in the teaching of science

Summary The thrust of this article is that although different theories may share some of the same terminology they may differ considerably in the interpretation which they impose on it and, therefore, on the educational practices which they underwrite. Specifically a brief examination has been made here of the concept of cognitive conflict as it occurs in the theories of Bruner, Case and Piaget-Inhelder, and of the similarities and differences in classroom practices which arise from theoretical commitment.