PURPOSE: The San Antonio Tennis Heat Stress Study is an ongoing, multi-year observational study. The current update is a report of interim findings, prompted by the emergence of significant new results. METHODS: The USTA Boys' 14's National Hardcourt Championship is held annually in the first 2 weeks of August in San Antonio, Texas. During the period 1999 to 2006, complete data was collected for all players and all tournament matches, a total of 1507 players, 2920 singles matches and 897 doubles matches. On-site heat stress monitoring was carried out using an industrial heat stress monitor with logging capabilities. For the current study, singles matches were analyzed that met these criteria: Only the second singles match of the day was considered, and each player must have played only one singles match earlier in the day, but no doubles match earlier in the day. RESULTS: 411 matches met the study criteria and were analyzed. Average WBGT during the matches was 89.6± 2.5°F (32±1.4°C), and 85% of these matches would have been postponed due to heat stress under the Australian Open Extreme Heat Policy. Differences between winning and losing players were analyzed. Continuous variables were tested and normal distribution was demonstrated for all sets of differences. Chi-square analysis was carried out for categorical variables, and the following variables were not found to differ significantly between winners and losers: Hometown heat stress zone (p=−0.64), BSA(p = 0.10), body mass index (p=−0.09), and day-before plus day-of degree minutes up to the start of the match (p=0.46). Significant discriminating factors were player seed (p<0.0001), same-day degree-minutes accumulated by the players up to the time of the start of the match (p=0.0006), time between matches (p=0.012), KG/BSA (p=−0.018), and age (p=0.04). When the effect of seeding was removed, same-day degree minutes up to the time of the start of the match (p = 0.0039), time between matches (p=0.027), age and KG/B SA remained significant factors. CONCLUSIONS: In national junior tennis championship singles matches played in very difficult heat stress conditions, (1) player seed, (2) degree-minutes of heat stress acquired during a morning match, (3) interval between matches, (4) KG/BSA and (5) age showed significant ability to predict outcome of an afternoon match.
PURPOSE: High levels of heat stress have been shown to adversely affect exercise performance and promote injury. There have been no published prospective studies of heat stress in national tennis competition. The current study was carried out to assess the hypothesis that cumulative heat stress load influences tennis match outcome. METHODS: The USTA Boys' 14's National Hardcourt Championship is held annually in the first 2 weeks of August in San Antonio, Texas. During the period 1999 to 2005, data was collected for all players and all tournament matches, a total of 1334 players, 2582 singles matches and 812 doubles matches. On-site heat stress monitoring was carried out using an industrial heat stress monitor. For the current study, singles matches were analyzed that met these criteria: Only the second singles match of the day was considered, and each player must have played a singles match earlier in the day, but no doubles match earlier in the day. RESULTS: 370 matches met the study criteria and were analyzed. Average Wet Bulb Globe Temperature during the matches was 89.5 ± 2.3°F (31.9 ± 1.3°C). Differences between the winning player and the losing player were analyzed for each match. Continuous variables were tested and normal distribution was demonstrated for all sets of differences. Chi-square analysis was carried out for categorical variables, and the following variables were not found to differ significantly between winners and losers: Age (p=0.28), hometown heat stress zone (p=−0.876), body surface area (p = 0.336), body mass index (p=−0.338), KG/BSA (p=−0.123), tournament total degree-minutes of heat stress up to the start of the match (p=−0.825), day-before plus day-of degree minutes up to the start of the match (p=0.659), and interval between matches (p=0.081). The only significant discriminating factors were player seed (p<0.0001) and same-day degree-minutes accumulated by the players up to the time of the start of the match (p=0.015). When the effect of seeding was removed, same-day degree minutes up to the time of the start of the match remained a significant factor (p = 0.034). CONCLUSIONS: In national junior tennis championship singles matches played in very hot conditions, degree-minutes of heat stress acquired during a morning match showed significant ability to predict outcome of an afternoon match. This relationship is maintained after numerous possible confounding factors have been considered. Whether this is a direct heat-related effect or reflects some other process such as player efficiency in shortening matches cannot be determined from available data.
Click to increase image sizeClick to decrease image size Notes 1 Meanwhile, coming in under the radar, a language first devised in business schools and now ubiquitous has been performing its own revolution, transforming public discourse to an unprecedented degree. 2 No more than I would suggest that there is anything inappropriate about two of the four endorsements on the back cover of Carey's book being written by journalists working for the Sunday Times, of which Professor Carey is the chief reviewer.
ACSM heat stress guidelines are expressed in terms of WBGT. These guidelines enjoy limited use, at least in part due to the expense of instruments capable of measuring WBGT. Previous work (Med. Sci. Sports Exerc. 36:S316, 2004) demonstrated that data obtained by using an inexpensive digital psychrometer could predict WBGT with reasonable accuracy. Whether inexperienced users could employ these devices effectively was not known. PURPOSE To determine whether accurate estimation of WBGT could be achieved using data gathered by inexperienced observers in a novel environment. METHODS 3 naive observers were recruited to obtain serial dry bulb and wet bulb temperatures over a 4 day period during a junior tennis tournament in San Antonio, TX, as part of a multi-year heat stress study. The observers were given 5 minutes of instruction in use of the digital psychrometer plus an instruction sheet. The observers were stationed at the main tournament venue and at secondary venues 5.0 km and 12.9 km away. The temperature data obtained by these observers was used to estimate WBGT using this formula: Estimated WBGT = ((((Dry Bulb Temp °C + Wet Bulb Temp °C)/2)*0.9815)+0.3614). The estimated WBGT values obtained by the observers were compared with WBGT measured values recorded at the main tournament venue using an industrial instrument. The observers were blinded both to the measured WBGT values and to the model formula. RESULTS Main venue: 135 observations, mean error = 0 ± 1.1 °C; Venue 5.0 km away: 35 observations, mean error = 0.4 ± 1.1 °C; Venue 12.9 km away: 42 observations, mean error = 2.2 ± 1.4°C. CONCLUSION The model used in this study to predict WBGT was based on 357 paired observations obtained over a 3 month period in Tulsa, OK. Mean error for that model was 0 ± 1.1°C. WBGT estimates based on measurements made by inexperienced observers using the same digital psychrometers in San Antonio, TX, gave identical results at the main venue and very similar results at a venue 5.0 km distant. The unexpectedly low WBGT estimates obtained from a site 12.9 km distant were most likely related to the observer moving abruptly from a cool to a hot environment without waiting 15 minutes before making the measurements. This underscores the need to be in the test environment for 15 minutes before measurements are taken. With proper recording technique, inexpensive digital psychrometers can provide very good estimation of WBGT.
2150 Environmental heat stress can adversely affect athletic performance and lead to injury or death. ACSM guidelines designed to avoid these undesirable outcomes are expressed as WBGT. Devices for measuring WBGT tend to be unwieldy or very expensive, and this deters guidelines adherence. Accuracy of handy, inexpensive devices in estimating WBGT (devices that may facilitate guidelines utilization) has not been reported previously. PURPOSE: To assess the accuracy of inexpensive psychrometers for estimation of WBGT. METHODS: 233 measurement sessions were carried out between June 26 and Sept 7, 2003. Devices used included industrial heat stress monitors ($2000) (2), and a variety of consumer psychrometers: Aspirated psychrometer ($170) (1), digital psychrometer ($105) (2), and sling psychrometer ($70) (2). Measurements were made according to the manufacturers' directions, at intervals of no less than 20 min. (Median sampling interval = 33 min.) For each device type, Discomfort Index (DI) = (Dry Bulb Temp + Wet Bulb Temp)/2 was calculated, to approximate WBGT. These “raw” DI's were then modeled to optimize correlation to measured WBGT. The results were subjected to statistical analysis, expressed as Mean Error (WBGT-DI) ± standard deviation. RESULTS: Mean WBGT = 85 ± 7°F [29.4 ± 3.9°C] (Range: 95–59°F, 35–15°C). Aspirated psychrometer error: Raw = 2.2 ± 2.0°F [1.2 ± 1.1°C], modeled = 0 ± 1.2°F [0 ± 0.7°C] (N = 233); Digital psychrometer error: Raw = −0.3 ± 2.0°F [−0.2 ± 1.1°C], modeled = 0 ± 1.8°F [0 ± 1.0°C](N = 357); Sling psychrometer error: Raw = 2.2 ± 2.7°F [1.2 ± 1.5°C], modeled = 0 ± 1.7°F [0 ± 0.9°C] (N = 328). CONCLUSIONS: Inexpensive psychrometers can estimate WBGT to a reasonable degree of accuracy. Use of complex modeling techniques can improve the accuracy of this estimate considerably. To allow for application of these correction models to data on the practice field, a free program for Palm-type PDA's, Heat Stress Adviser, will be presented. This easy-to-use program contains calculators for conversion of sling and digital psychrometer data to estimated WBGT. Various organizations' heat stress guidelines and other useful information are also stored in the program.
Essentials of Molecular Photochemistry. By Andrew Gilbert and Jim Baggott. Blackwell: 1991. Pp.538. £17.95, $44.95
Nachrichten aus Chemie, Technik und LaboratoriumVolume 33, Issue 4 p. 287-291 Fernstudium Chemie an der Open University John Coyle, John CoyleSearch for more papers by this author John Coyle, John CoyleSearch for more papers by this author First published: April 1985 https://doi.org/10.1002/nadc.19850330404AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Volume33, Issue4April 1985Pages 287-291 RelatedInformation
In 25 pentobarbital anesthetized dogs we measured refractory periods (RPs) of regularly driven complexes and premature ventricular depolarizations (PVDs) with a range of coupling intervals or of regularly driven complexes and the complex following the PVD, i.e. the postextrasystolic depolarization (PED). Measurements were made during control periods and during occlusion of a branch of the left anterior descending coronary artery. The difference in control and occlusion RPs was less following some PVDs with short coupling intervals than following other PVDs with longer coupling intervals. Variations in the coupling interval of PVDs had less effect on RPs of the PVDs in ischemic than in nonischemic tissue. RPs of PEDs were prolonged with respect to RPs of regularly driven complexes in both ischemic and nonischemic tissue, but the prolongation in ischemic tissue was significantly greater than that in nonischemic tissue, 8 +/- 4 msec and 2 +/- 2 msec respectively, p less than .001. The difference in effect of PVDs on RPs of ischemic and nonischemic tissue results in greater disparity of refractoriness between ischemic and nonischemic tissue following some long coupling interval PVDs than following some PVDs with shorter coupling intervals. In addition the greater prolongation of RPs of PEDs in ischemic than in nonischemic tissue can result in increased disparity in RPs than the disparity between ischemic and nonischemic tissue present during regular drive.
Aspects of Organic Photochemistry.By W. M. Horspool. Pp. viii + 290. (Academic: London and New York, 1976.) £9.50; $20.75.
Since the Taylor Report of 1990 many football clubs in Britain have opted to relocate rather than reconstruct their existing stadia. Utilising case studies undertaken by postgraduate students in the De Montfort International Centre for Sports History and Culture, this article examines how fans have been treated by the clubs when such moves were being discussed. The conclusion that generally their interests have not been considered fits the historical pattern of relationships between clubs and their supporters. It is predicted that the situation will worsen both as the revenue from the electronic turnstile becomes more important then gate-money and as city financiers increasingly gain power and influence on club boards. The article concludes with an analysis of ways that fans can fight back. Few think that the US franchise system, where teams are bought and sold like any other commodity, will take hold in Britain. The fans won't stand for it, they say. But in America, with TV and merchan- dising bankrolling sports, owners don't have to listen to them (Connett & Thomas, 1996). The mooted solution is a new 60,000 stadium on a greenfield site far away, beyond the city walls, not far from the M25 in Hertfordshire. Every Nick Hornby in the parish is against such a move from their spiritual home; but cold logic and hard brass are usually five goals ahead of soft old sentiment (Butler, 1997). Just under a century ago Sheffield Wednesday Football Club moved from its Olive Grove ground to its present home at Owlerton2 which at the time was miles beyond the city boundary and poorly served by public transport. Nevertheless in the first season at the new ground attendances averaged some 3,000 spectators more than in the previous one at the old site. One reason was that the club had done much to secure their fans' acceptance of the move by the democratic manner in which they went about their choice of ground. Since 1887, Wednesday had occupied Olive Grove, conveniently close to the city centre, and the Ground had witnessed the club's entry into the Football League in 1892. Although it was not an imposing ground, nor especially picturesque, the regular patrons regarded it with affection and pride and, accord- ing to an early historian of the club, 'it appeared to encourage the feeling in the
