Rethinking the 'problem' of gender and IT schooling: discourses in literature

A review of the international research literature pertaining to gender and information technology (IT) schooling reveals changing ideas about what constitutes a gender problem. Much of the literature is concerned with gender differences in computer uses and interests and perceived disadvantages accruing to females as a result of these differences. This reflects and contributes to a dominant liberal equity discourse. Growing awareness of the limitations of earlier research, the changing nature of IT schooling, contradictions in students’ computer interests and dissatisfaction with simplistic explanations has led, however, to post-structural rethinking and the emergence of a critical discourse. Assumptions of essential differences and deficit ways of thinking are challenged. Persistent gender differences in IT use are explored in their social complexity and the very notion that there is a gender problem is problematised. This presents a different and ultimately more satisfying way of thinking about the problem of gender and IT schooling

Reducing aerodynamic drag by adopting a novel road-cycling sprint position

Purpose: To assess the influence of seated, standing, and forward-standing cycling sprint positions on aerodynamic drag (CdA) and the reproducibility of a field test of CdA calculated in these different positions. Methods: A total of 11 recreational male road cyclists rode 250 m in 2 directions at around 25, 32, and 40 km·h. Results: A main effect of position showed that the average CdA of the 2 d was lower for the forward-standing position (0.295 [0.059]) compared with both the seated (0.363 [0.071], P = .018) and standing positions (0.372 [0.077], P = .037). Seated and standing positions did not differ from each other. Although no significant difference was observed in CdA between the 2 test days, a poor between-days reliability was observed. Conclusion: A novel forward-standing cycling sprint position resulted in 23% and 26% reductions in CdA compared with a seated and standing position, respectively. This decrease in CdA could potentially result in an important increase in cycling sprint velocity of 3.9-4.9 km·

Validity of the Velocomp PowerPod compared with the Verve Cycling InfoCrank power meter

Purpose: To determine the validity of the Velocomp PowerPod power meter in comparison with the Verve Cycling InfoCrank power meter. Methods: This research involved 2 separate studies. In study 1, 12 recreational male road cyclists completed 7 maximal cycling efforts of a known duration (2 times 5 s and 15, 30, 60, 240, and 600 s). In study 2, 4 elite male road cyclists completed 13 outdoor cycling sessions. In both studies, power output of cyclists was continuously measured using both the PowerPod and InfoCrank power meters. Maximal mean power output was calculated for durations of 1, 5, 15, 30, 60, 240, and 600 seconds plus the average power output in study 2. Results: Power output determined by the PowerPod was almost perfectly correlated with the InfoCrank (r \u3e .996; P \u3c .001) in both studies. Using a rolling resistance previously reported, power output was similar between power meters in study 1 (P = .989), but not in study 2 (P = .045). Rolling resistance estimated by the PowerPod was higher than what has been previously reported; this might have occurred because of errors in the subjective device setup. This overestimation of rolling resistance increased the power output readings. Conclusion: Accuracy of rolling resistance seems to be very important in determining power output using the PowerPod. When using a rolling resistance based on previous literature, the PowerPod showed high validity when compared with the InfoCrank in a controlled field test (study 1) but less so in a dynamic environment (study 2)

Reliability and validity of maximal mean and critical speed and metabolic power in Australian youth soccer players

© 2020 Cameron Lord, Anthony J. Blazevich, Chris R. Abbiss, Fadi Ma\u27ayah, published by Sciendo 2020. The reliability and validity of maximal mean speed (MMS), maximal mean metabolic power (MMPmet), critical speed (CS) and critical metabolic power (CPmet) were examined throughout the 2016-2017 soccer National Youth League competitions. Global positioning system (GPS) data were collected from 20 sub-elite soccer players during a battery of maximal running tests and four home matches. A symmetric moving average algorithm was applied to the instantaneous velocity data using specific time windows (1, 5, 10, 60, 300 and 600 s) and peak values were identified. Additionally, CS and CP¬met values calculated from match data were compared to CS and CPmet values determined from previously validated field tests to assess the validity of match values. Intra-class correlation (one-way random absolute agreement) scores ranged from 0.577 to 0.902 for speed, and from 0.701 to 0.863 for metabolic power values. Coefficients of variation (CV) ranged from good to moderate for speed (4-6%) and metabolic power (4-8%). Only CS and CPmet values were significantly correlated (r = 0.842; 0.700) and not statistically different (p = 0.066; 0.271) to values obtained in a shuttle-running critical test. While the present findings identified match-derived MMS, MMPmet, CS and CPmet to be reliable, only CS and CPmet derived from match play were validated to a CS field test that required changes in speed and direction rather than continuous running. This suggests that both maximal mean and critical speed and metabolic power analyses could be alternatives to absolute distance and speed in the assessment of match running performance during competitive matches

Intrarater reliability and agreement of the physioflow bioimpedance cardiography device during rest, moderate and high-intensity exercise

The PhysioFlow bioimpedance cardiography device provides key measures of central systolic and diastolic and peripheral vascular function. Many of these variables have not been assessed for intrarater reliability and agreement during rest, submaximal exercise and high-intensity interval exercise. Twenty healthy adults (age: 26±4 years) completed two identical trials beginning with five minutes of rest followed by two 5-minute submaximal cycling bouts at 50% and 70% of peak power output. Subjects then completed ten 30-second cycling intervals at 90% of peak power output interspersed with 60 s of passive recovery. Bioimpedance cardiography (PhysioFlow; Manatec Biomedical, France) monitored heart rate, stroke volume, cardiac output, stroke volume index, cardiac index, ventricular ejection time, contractility index, ejection fraction, left cardiac work index, end diastolic volume, early diastolic filling ratio, systemic vascular resistance and systemic vascular resistance index continuously throughout both trials. Intraclass correlation coefficients (ICC), standard errors of measurement and minimal detectable differences were calculated for all variables. Heart rate, stroke volume, cardiac output, left cardiac work index and end diastolic volume demonstrated a good level of reliability (ICC>.75) at rest, during submaximal exercise and high-intensity interval exercise. All other variables demonstrated inconsistent reliability across activity types and intensities. When using the PhysioFlow device, heart rate, stroke volume, cardiac output, left cardiac work index and end diastolic volume were deemed acceptable for use regardless of exercise type (continuous vs. interval) or intensity (low, moderate, or high). However, other variables measured by this device appear less reliable

Influence of race distance and biological sex on age-related declines in triathlon performance: Part A

This study examined the effect of biological sex and race distance on the age-related declines in swimming, cycling, running and overall performances of the sprint, Olympic, Half-Ironman and Ironman triathlons. Individual discipline and overall performance time of the top 20% non-elite males (n=468) and females (n=146) were compared by categorizing into four 10-year age-groups (20-29, 30-39, 40-49, 50+ years) and normalising to the mean performance time of the fastest age-group for each race. An earlier, larger and faster rate of decline (p=0.01) in performance with ageing was observed in females (≥30 years, 9.3%, 3.0% per decade respectively) and males (≥40 years, 5.9%, 2.2% per decade, respectively) for the longer events (half-Ironman and Ironman) compared with the shorter distances (sprint and Olympic, ≥50 years for both sexes). A greater magnitude of decline was observed in swimming for both sexes, especially in the longer events, when compared with cycling and running (12.8%, 5.6%, 9.3% for females, 9.4%, 3.7%, 7.3% for males, in the swim, cycle and run disciplines, respectively). These results indicate that both race distance and biological sex influence the age-related decline in triathlon performance and could aid athletes in optimising training programs to attenuate the age-related declines in performance across different disciplines and distances. Specifically, older athletes may benefit from greater emphasis on swim training and factors that may influence performance during longer distance triathlons

Neuromuscular fatigue and muscle damage following a simulated singles badminton match

Purpose: To understand muscle damage in badminton, changes in neuromuscular function were investigated after simulated badminton singles matches performed by ten state-level male players. Methods: Each participant played eight matches and measurements were taken before, immediately after, and 1 and 24 h after each match. Maximal voluntary isometric contraction (MVC) torque of the knee extensors and flexors, voluntary activation (VA) during MVC and torques generated by doublet (TDoublet), 20 (T20) and 80 Hz (T80) electrical stimulations of the knee extensors were measured from the dominant leg (the racket-hold arm side). Muscle soreness was assessed by a 100-mm visual analogue scale from both legs. The number of lunges performed by each participant in each match was analysed by videos, and its relations to other measures were examined. Results: Pre-match knee extensor and flexor MVC torques were 278.4 ± 50.8 Nm and 143.0 ± 36.2 Nm, respectively. Knee extensor MVC torque of the dominant leg decreased immediately (12.0 ± 2.9 %) and 1 h post-match (16.0 ± 3.2 %), but returned to baseline at 24 h post-match. VA (11.4 ± 2.9 %), TDoublet (13.1 ± 6.0 %), T20 (31.1 ± 12.3 %) and T80 (25.5 ± 7.9 %) decreased (p \u3c 0.01) immediately post-match but recovered by 24 h post-match. A significant correlation (r = − 0.64, p \u3c 0.01) was observed between the total number of lunges performed in a match (160 – 240 times) and the magnitude of decrease in MVC torque (6.4 – 14.7 %). Muscle soreness developed more (p \u3c 0.05) for the dominant (51.5 ± 11.6 mm) than the non-dominant leg (18.8 ± 8.6 mm). Conclusion: Muscle damage induced by singles badminton matches was minimal, but the more the lunges are performed, the greater the neuromuscular fatigue

Acute dehydration impairs endurance without modulating neuromuscular function

Introduction/Purpose: This study examined the influence of acute dehydration on neuromuscular function. Methods: On separate days, combat sports athletes experienced in acute dehydration practices (n = 14) completed a 3 h passive heating intervention (40∘C, 63% relative humidity) to induce dehydration (DHY) or a thermoneutral euhydration control (25∘C, 50% relative humidity: CON). In the ensuing 3 h ad libitum fluid and food intake was allowed, after which participants performed fatiguing exercise consisting of repeated unilateral knee extensions at 85% of their maximal voluntary isometric contraction (MVIC) torque until task failure. Both before and after the fatiguing protocol participants performed six MVICs during which measures of central and peripheral neuromuscular function were made. Urine and whole blood samples to assess urine specific gravity, urine osmolality, haematocrit and serum osmolality were collected before, immediately and 3 h after intervention. Results: Body mass was reduced by 3.2 ± 1.1% immediately after DHY (P \u3c 0.001) but recovered by 3 h. Urine and whole blood markers indicated dehydration immediately after DHY, although blood markers were not different to CON at 3 h. Participants completed 28% fewer knee extensions at 85% MVIC (P \u3c 0.001, g = 0.775) and reported a greater perception of fatigue (P = 0.012) 3 h after DHY than CON despite peak torque results being unaffected. No between-condition differences were observed in central or peripheral indicators of neuromuscular function at any timepoint. Conclusion: Results indicate that acute dehydration of 3.2% body mass followed by 3 h of recovery impairs muscular strength-endurance and increases fatigue perception without changes in markers of central or peripheral function. These findings suggest that altered fatigue perception underpins muscular performance decrements in recovery from acute dehydration

Influence of age and sex on pacing during Sprint, Olympic, Half-Ironman and Ironman triathlons: Part B

The aim of this study was to investigate the influence of biological sex and age on the pacing strategies adopted by non-drafting top triathletes during the cycle and run disciplines of a Sprint, Olympic, half-Ironman and Ironman triathlon. Split times of the top 20% non-elite males (n=468) and females (n=146) were determined using official race transponders and a video capture system for pre-determined sections of the cycle and run disciplines of four triathlon distances. Indices of pacing were calculated to compare between sexes and age-groups. Results of this study indicated that different pacing strategies were adopted between athletes of different age and sex over the various triathlon disciplines and distances. Females were more aggressive during the initial stages of the cycling discipline across all distances (sprint - 2.1% p=0.024; Olympic - 1.6%, p=0.011; half-Ironman- 1.5%, p<0.001; Ironman - 1.7%, p<0.001 higher relative to mean) compare with males. Younger athletes (20-29 y) tend to begin the run faster (2.0 to 3.0% faster than other age-groups, p<0.029) during the sprint, Olympic and half-Ironman triathlons. These results indicate that different pacing strategies are adopted by non-drafting top athletes of different age and sex. Optimal pacing strategies may differ between sex and ages; therefore individuals may need to trial different strategies to develop their own optimal pacing profile for triathlon events of varying distances

Iron supplementation and altitude: Decision making using a regression tree

[No abstract available