**Q: How does RRWP estimate group water needs, exactly?**

A: RRWP uses a patent-pending algorithm known as H_{2}Q Technology™ to accurately estimate the need of the ‘weighted average’ runner, which is determined from a normal distribution of body sizes and marathon finishing times estimated or obtained from more than 3,000,000 runners. Body weights and finishing times are then binned and weighted by their frequency distributions. A range of possible environmental temperatures is included in each bin. A proprietary algorithm is used which requires the user to input race distance, number of runners, and air temperature to arrive at total water needs for the race. On the basis of the central limit theorem, RRWP provisions are enough to accurately estimate the water loss needs of everyone participating so long as the sample mean is representative (heterogeneous, sufficiently large and normally distributed).

**Q: Can RRWP be used to estimate “individual” exercise water needs?**

A: RRWP should NOT be used to estimate water needs for individuals. The equation provides what the ‘weighted average person’ will need, thus it will in many cases over-estimate or under-estimate individual needs despite accurately estimating enough water to cover the water losses of everyone participating. If knowledge of individual water loss needs are desired, H_{2}Q Technology™ should be used in conjunction with measurements of air temperature and “individual” energy expenditure [https://wordpress.com/page/sportssciencesynergy.com/35].

**Q: What is the range of environments covered by RRWP?**

A: RRWP was designed for air temperatures anticipated during the most popular months for road races (April – October). The optimum ‘domain of validity’ for RRWP is 10 to 35ºC (50 to 95ºF). However, RRWP will allow users to input air temperatures ranging from 4 to 40ºC (39 to 104ºF). The air temperature used should be the average forecasted for the duration of the race.

**Q: How does RRWP estimate how much water is spilled or used for dowsing?**

A: RRWP water needs estimates are synonymous with runner sweat losses. RRWP provisions are enough to cover the sweat losses of all runners, assuming that all runners drink to replace sweat losses (1:1). Some runners may drink more or less than this amount, but RRWP assures that the right amount is placed on the course to replace sweat losses. RRWP also has a 10% spillage factor built into it, but this is an estimate for which there are no quantitative data. Therefore, calculations should be considered as a valid starting point for water planning and adjusted in accordance with the history of actual water usage on the course.

**Q: How accurate is RRWP?**

A: The accuracy of RRWP for predicting group water needs can be gleaned from close agreement between predicted and measured group sweating rates in 11 field and laboratory studies of distance runners. The grand mean sweating rate of 11 groups, stemming from a sample size of 109 individual runners, was 1.00 ± 0.38 L/h; the RRWP prediction was 0.98 ± 0.35 L/h*, the difference of which (20 mL) is a little larger than the typical volume of one sip of water (16 mL). The hourly error for RRWP is therefore less than half of one fluid ounce for this data set. A validation study is presently underway and targeted for publication in 2018. *(*without 10% spillage factor*)

**Q: How does RRWP determine the number of cups needed?**

A: RRWP assumes that 4 fluid ounces will be poured into each cup. It takes 32 cups to empty one gallon of fluid. The rest is simple arithmetic.

**Q: Why does RRWP assume that water should be distributed equally among fluid stations?**

A: There are different strategies for supplying water on a race course which depend on logistics, course design, and the number of registered runners (to name a few). RRWP simply divides evenly the total amount of water planned across the number of water stations entered. It is a suggestion aimed at saving the water planner a calculation (similar to cup numbers), but also reduces the potential for over- or under-supplying runners at any one station.

**Q: Do I really ‘need’ RRWP as a race director?**

A: Aid stations are an essential part of any road race, but there is presently no scientifically defensible way of accurately planning water needs for large groups in sport the way there is in the military (https://www.army.mil/article/136391). RRWP was developed to narrow race and medical director uncertainties about water planning that relate to changes in weather, participant numbers, and race distance. RRWP can improve pre-event planning, race-day preparedness, and is consistent with growing eco-friendly race initiatives. Think of RRWP as a $9.99 supplemental insurance policy that can help reduce the risks, waste, and costs associated with executing all of your road races.

**Q: When will RRWP be available for download?**

A: RRWP is now available for purchase on the App Store® for iPhone® and iPad® platforms (https://itunes.apple.com/us/app/rrwp/id1249618165?ls=1&mt=8).

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