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Supplemental Digital Content is Available in the Text.High-speed running (HSR) has been documented within rugby league to differentiate playing standard and position and often precedes pivotal match events. Practitioners and researchers place importance on HSR because of its inclusion in assessing the demands of training and match play to help prescribe accurate training loads and recovery methods. HSR can be quantified in absolute terms whereby the same threshold speed is applied to all players (e.g., 5.0 m·s−1). Within rugby league, differences in tactical demand, anthropometric, and physical fitness characteristics exist between positions and players, suggesting that absolute HSR thresholds may not be appropriate because of underestimations and overestimations of HSR data. Alternatively, practitioners may individualize the threshold speed to individual players' physical qualities such as peak sprint speed, maximal aerobic speed (MAS), or the speed at which the ventilatory thresholds occur. Individualizing HSR warrants the practitioner to select a valid and practical test to quantify the HSR threshold speed. It is suggested that using peak sprint speed to quantify HSR can produce erroneous interpretation of HSR data while the practicality of specific physiological derived thresholds can be questioned. Implementing MAS to quantify HSR using a set time/distance trial may be the most appropriate approach for rugby league practitioners.

This paper is centered on the principle author's (John) personal narrative of a coach-athlete relationship in golf, and how the original story altered through a process of shared critical thinking. On first telling, John explained to his co-authors how he considered himself to be the victim of bad coaching practice following his coach's failure to correctly diagnose a key but subtle fault with his golf swing. The initial rendering was a story of blame, betrayal, and of a coach who ultimately failed to provide the expert service required. Having shared and critically reflected upon this comfortable version of events with his co-authors, John explores how he came to understand his role in an ultimately dysfunctional coaching relationship in a different way. Rather than being a blameless victim, John began to explore his own contribution to the process of relationship breakdown. For example, his conscious decision to not share his thoughts and feelings about his golf swing with his coach; an act of stubbornness that led John to ‘test’ his coach in a way that could only lead to failure. Finally, the author team considers the value, role and issues associated with reflective writing in coaching, especially as they relate to the development of co-constructed narratives.

The gravitational potential of clusters of galaxies acts as a cosmic telescope allowing us to find and study galaxies at fainter limits than otherwise possible and thus probe closer to the epoch of formation of the first galaxies. We use the Bullet cluster 1E0657 - 56 (z = 0.296) as a case study, because its high mass and merging configuration makes it one of the most efficient cosmic telescopes we know. We develop a new algorithm to reconstruct the gravitational potential of the Bullet cluster based on a non-uniform adaptive grid, combining strong and weak gravitational lensing data derived from deep Hubble Space Telescope/Advanced Camera for Surveys F606W-F775W-F850LP and ground-based imaging. We exploit this improved mass map to study z [?] 5-6 Lyman break galaxies (LBGs), which we detect as dropouts. One of the LBGs is multiply imaged, providing a geometric confirmation of its high redshift, and is used to further improve our mass model. We quantify the uncertainties in the magnification map reconstruction in the intrinsic source luminosity, and in the volume surveyed, and show that they are negligible compared to sample variance when determining the luminosity function of high-redshift galaxies. With shallower and comparable magnitude limits to Hubble Ultra Deep Field (HUDF) and Great Observatories Origins Deep Survey (GOODS), the Bullet cluster observations, after correcting for magnification, probe deeper into the luminosity function of the high-redshift galaxies than GOODS and only slightly shallower than HUDF. We conclude that accurately focused cosmic telescopes are the most efficient way to sample the bright end of the luminosity function of high-redshift galaxies and--in case they are multiply imaged--confirm their redshifts.

The galaxy cluster RX J1347.5-1145 is one of the most X-ray luminous and most massive clusters known. This makes it a prime target for studying issues addressing cluster formation and cosmology. Despite the naive expectation that mass estimation for this cluster should be straightforward (high mass and favorable redshift make it an efficient lens; it is bright in X-rays and appears to be fairly relaxed), some studies have reported very discrepant mass estimates. In this paper we present new high-resolution HST ACS and Chandra X-ray data. The high resolution and sensitivity of ACS enabled us to detect and quantify several new multiple images; we use a total of eight for the strong-lensing analysis. Combining it with shape measurements of weak-lensing sources in the central regions of the cluster, we derive a high-resolution, absolutely calibrated mass map. This map provides the best available quantification of the total mass of the central part of the cluster to date. We compare the reconstructed mass with that inferred from the new Chandra X-ray data. Both mass estimates agree extremely well in the observed region (within 400 h[?]170 kpc of the cluster center). In addition we study the major baryonic components (gas and stars) and hence derive the dark matter distribution in the center of the cluster. We find that the dark matter and baryons are both centered on the BCG within the uncertainties (alignment is better <10 kpc). We measure the corresponding dark matter profile and find it consistent with both NFW and cored profiles, indicating that a more extended radial analysis is needed to pinpoint the concentration parameter, and hence the inner slope of the dark matter profile.

The galaxy cluster 1ES 0657-558 (z = 0.296) is remarkably well suited for addressing outstanding issues in both galaxy evolution and fundamental physics. We present a reconstruction of the mass distribution from both strong and weak gravitational lensing data. Multicolor, high-resolution HST ACS images allow detection of many more arc candidates than were previously known, especially around the subcluster. Using the known redshift of one of the multiply imaged systems, we determine the remaining source redshifts using the predictive power of the strong-lens model. Combining this information with shape measurements of "weakly" lensed sources, we derive a high-resolution, absolutely calibrated mass map, using no assumptions regarding the physical properties of the underlying cluster potential. This map provides the best available quantification of the total mass of the central part of the cluster. We also confirm the result from Clowe and colleagues that the total mass does not trace the baryonic mass.

We present a comprehensive lensing analysis of the rich cluster Cl 0024+1654 (z = 0.395) based on panoramic sparse-sampled imaging conducted with the WFPC2 and STIS cameras on board the Hubble Space Telescope. By comparing higher fidelity signals in the limited STIS data with the wider field data available from WFPC2, we demonstrate an ability to detect reliably weak-lensing signals to a cluster radius of [?]5 himg1.gif Mpc, where the mean shear is around 1%. This enables us to study the distribution of dark matter with respect to the cluster light over an unprecedented range of cluster radii and environments. The projected mass distribution reveals a secondary concentration representing 30% of the overall cluster mass, which is also visible in the distribution of cluster member galaxies. We develop a method to derive the projected mass profile of the main cluster taking into account the influence of the secondary clump. We normalize the mass profile determined from the shear by assuming that background galaxies selected with 23 < I < 26 have a redshift distribution statistically similar to that inferred photometrically in the Hubble Deep Fields. The total mass within the central region of the cluster is independently determined from strong-lensing constraints according to a detailed model that utilizes the multiply imaged arc at z = 1.675. Combining strong and weak constraints, we are able to probe the mass profile of the cluster on scales of 0.1-5 Mpc, thus providing a valuable test of the universal form proposed by Navarro, Frenk, & White (NFW) on large scales. A generalized power-law fit indicates an asymptotic three-dimensional density distribution of r [?] r-n with n > 2.4. An isothermal mass profile is therefore strongly rejected, whereas an NFW profile with M200 = 6.1img2.gif x 1014 himg1.gif M provides a good fit to the lensing data. We isolate cluster members according to their optical/near-infrared colors; the red cluster light closely traces the dark matter with a mean mass-to-light ratio of M/LK = 40 +- 5 h65 M/L. Similar profiles for mass and light on 1-5 Mpc scales are expected if cluster assembly is largely governed by infalling groups.