Reliability of a 2-Bout exercise test on a Wattbike cycle ergometer

Purpose: To determine the intraday and interday reliability of a 2 × 4-min performance test on a cycle ergometer (Wattbike) separated by 30 min of passive recovery (2 × 4MMP). Methods: Twelve highly trained cyclists (mean ± SD; age = 20 ± 2 y, predicted VO2max = 59.0 ± 3.6 mL · kg–1 · min–1) completed six 2 × 4MMP cycling tests on a Wattbike ergometer separated by 7 d. Mean power was measured to determine intraday (test 1 [T1] to test 2 [T2]) and interday reliability (weeks 1–6) over the repeated trials. Results: The mean intraday reliabilities of the 2 × 4MMP test, as expressed by the typical error of measurement (TEM, W) and coefficient of variation (CV, %) over the 6 wk, were 10.0 W (95% confidence limits [CL] 8.2–11.8), and 2.6% (95%CL 2.1–3.1), respectively. The mean interday reliability TEM and CV for T1 over the 6 wk were 10.4 W (95%CL 8.7–13.3) and 2.7% (95%CL 2.3–3.5), respectively, and 11.7 W (95%CL 9.8–15.1) and 3.0% (95%CL 2.5–3.9) for T2. Conclusion: The testing protocol performed on a Wattbike cycle ergometer in the current study is reproducible in highly trained cyclists. The high intraday and interday reliability make it a reliable method for monitoring cycling performance and for investigating factors that affect performance in cycling events

Effects of two contrast training programs on jump performance in rugby union players during a competition phase

Purpose: There is little literature comparing contrast training programs typically performed by team-sport athletes within a competitive phase. We compared the effects of two contrast training programs on a range of measures in high-level rugby union players during the competition season. Methods: The programs consisted of a higher volume-load (strength-power) or lower volume-load (speed-power) resistance training; each included a tapering of loading (higher force early in the week, higher velocity later in the week) and was performed twice a week for 4 wk. Eighteen players were assessed for peak power during a bodyweight countermovement jump (BWCMJ), bodyweight squat jump (BWSJ), 50 kg countermovement jump (50CMJ), 50 kg squat jump (50SJ), broad jump (BJ), and reactive strength index (RSI; jump height divided by contact time during a depth jump). Players were then randomized to either training group and were reassessed following the intervention. Inferences were based on uncertainty in outcomes relative to thresholds for standardized changes. Results: There were small between-group differences in favor of strength-power training for mean changes in the 50CMJ (8%; 90% confidence limits, ±8%), 50SJ (8%; ±10%), and BJ (2%; ±3%). Differences between groups for BWCMJ, BWSJ, and reactive strength index were unclear. For most measures there were smaller individual differences in changes with strength-power training. Conclusion: Our findings suggest that high-level rugby union athletes should be exposed to higher volume-load contrast training which includes one heavy lifting session each week for larger and more uniform adaptation to occur in explosive power throughout a competitive phase of the season

Sleep and performance during a preseason in elite rugby union athletes

BACKGROUND: Preseason training optimises adaptations in the physical qualities required in rugby union athletes. Sleep can be compromised during periods of intensified training. Therefore, we investigated the relationship between sleep quantity and changes in physical performance over a preseason phase in professional rugby union athletes. METHODS: Twenty-nine professional rugby union athletes (Mean ± SD, age: 23 ± 3 years) had their sleep duration monitored for 3 weeks using wrist actigraphy. Strength and speed were assessed at baseline and at week 3. Aerobic capacity and body composition were assessed at baseline, at week 3 and at week 5. Participants were stratified into 2 groups for analysis: 7 h 30 min sleep per night (HIGH, n = 14). RESULTS: A significant group x time interaction was determined for aerobic capacity (p = 0.02, d = 1.25) at week 3 and for skinfolds at week 3 (p < 0.01, d = 0.58) and at week 5 (p = 0.02, d = 0.92), in favour of the HIGH sleep group. No differences were evident between groups for strength or speed measures (p ≥ 0.05). CONCLUSION: This study highlights that longer sleep duration during the preseason may assist in enhancing physical qualities including aerobic capacity and body composition in elite rugby union athletes

Astrometry and geodesy with radio interferometry: experiments, models, results

Summarizes current status of radio interferometry at radio frequencies between Earth-based receivers, for astrometric and geodetic applications. Emphasizes theoretical models of VLBI observables that are required to extract results at the present accuracy levels of 1 cm and 1 nanoradian. Highlights the achievements of VLBI during the past two decades in reference frames, Earth orientation, atmospheric effects on microwave propagation, and relativity.Comment: 83 pages, 19 Postscript figures. To be published in Rev. Mod. Phys., Vol. 70, Oct. 199

Determination of the Michel Parameters rho, xi, and delta in tau-Lepton Decays with tau --> rho nu Tags

Using the ARGUS detector at the $e^+ e^-$ storage ring DORIS II, we have measured the Michel parameters $\rho$, $\xi$, and $\xi\delta$ for $\tau^{\pm}\to l^{\pm} \nu\bar\nu$ decays in $\tau$-pair events produced at center of mass energies in the region of the $\Upsilon$ resonances. Using $\tau^\mp \to \rho^\mp \nu$ as spin analyzing tags, we find $\rho_{e}=0.68\pm 0.04 \pm 0.08$, $\xi_{e}= 1.12 \pm 0.20 \pm 0.09$, $\xi\delta_{e}= 0.57 \pm 0.14 \pm 0.07$, $\rho_{\mu}= 0.69 \pm 0.06 \pm 0.08$, $\xi_{\mu}= 1.25 \pm 0.27 \pm 0.14$ and $\xi\delta_{\mu}= 0.72 \pm 0.18 \pm 0.10$. In addition, we report the combined ARGUS results on $\rho$, $\xi$, and $\xi\delta$ using this work und previous measurements.Comment: 10 pages, well formatted postscript can be found at http://pktw06.phy.tu-dresden.de/iktp/pub/desy97-194.p

“You know that's a rip-off”: policies and practices surrounding micro-enterprises and poverty alleviation in South African township tourism

Supporting the development of small tourism businesses has been seen by policy-makers as a valuable means of alleviating poverty in South African townships. This perspective has been endorsed by several ‘responsible’ tourism businesses and academics. Following a review of the literature, this paper reports the findings of an empirical study that examined the practices of micro-business owners and the factors that shape their behaviour in two South African townships. In spite of significant visitor numbers, it finds that their narrow social networks and the imbalances of power between them and intermediaries such as travel agencies and tour operators prevent them from developing their businesses and sharing in the material gains that become available because of tourism. This analysis has important implications for local policy-makers and those advocating responsible tourism. For the former, it suggests a cessation of current initiatives in favour of greater regulation and alternative forms of investment. For the latter, it implies the need to reassess the utility of advocating responsible tourism to consumers in a context where they do not understand the dynamics which fashion what is on offer or the full implications of their choices

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

There was no funding support for this study. Disclosure. The authors declare no conflict of interest.Peer reviewedPublisher PD

Limitations of rupture forecasting exposed by instantaneously triggered earthquake doublet

Earthquake hazard assessments and rupture forecasts are based on the potential length of seismic rupture and whether or not slip is arrested at fault segment boundaries. Such forecasts do not generally consider that one earthquake can trigger a second large event, near-instantaneously, at distances greater than a few kilometers. Here we present a geodetic and seismological analysis of a magnitude 7.1 intra-continental earthquake that occurred in Pakistan in 1997. We find that the earthquake, rather than a single event as hitherto assumed, was in fact an earthquake doublet: initial rupture on a shallow, blind 2 reverse fault was followed just 19 seconds later by a second rupture on a separate reverse fault 50 km away. Slip on the second fault increased the total seismic moment by half, and doubled both the combined event duration and the area of maximum ground shaking. We infer that static Coulomb stresses at the initiation location of the second earthquake were probably reduced as a result of the first. Instead, we suggest that a dynamic triggering mechanism is likely, although the responsible seismic wave phase is unclear. Our results expose a flaw in earthquake rupture forecasts that disregard cascading, multiple-fault ruptures of this type

Pattern Recognition and Event Reconstruction in Particle Physics Experiments

This report reviews methods of pattern recognition and event reconstruction used in modern high energy physics experiments. After a brief introduction into general concepts of particle detectors and statistical evaluation, different approaches in global and local methods of track pattern recognition are reviewed with their typical strengths and shortcomings. The emphasis is then moved to methods which estimate the particle properties from the signals which pattern recognition has associated. Finally, the global reconstruction of the event is briefly addressed.Comment: 101 pages, 58 figure