Hello, welcome to the Weekly Mailbag. I'm Ray, from DCRainmaker. com. If you've ever searched for reviews on sports technology - you've probably come across my site. I write about my triathlon/running training in general, along with sports technology and whatever else seems interesting to me. I started the Weekly Mailbag series earlier this spring as an opportunity to share some of the answers of the many e-mailed questions I get each week.

If you enjoy what you find here, then feel free to click the links to find even more in depth information on each topic. And if you have any questions, you can always e-mail me directly. Thanks for reading!

1) Taking the Forerunner to the pool?
2) Best bet for trail running watch with altitude?
3) Auto-Pause, Running and Races (and why your distance might be short)

Question #1:Taking the Forerunner to the pool?
From Genevieve-

"I am a marathoner and use my Garmin FR305ONLY for running however, now that I have qualified for Boston, my next step would be … triathlon! So, I'm starting to swim but NOT outside yet, justin a pool. Would the Forerunnerwork in a pool? I am planning to wear the Garmin just like you said, on the back of my head, I'll wear my heart rate belt but I wonder if there is anything else I have to do with the watch? What would recommend as data? miles-h + distance + time??"

Unfortunately, as of this writing there are no models of the Forerunner that partake well in pool activities from a measurement standpoint. The closest you can get is in an outdoor pool using any of the Forerunners in your swim cap. And even then my previous testing of this particular scenario didn’t show terribly positive results- especially if you do flip turns.

Out of the pool and into open water, both the FR310XTand FR305 perform equally as well when in a swim cap on the back of your head pointing at the sky. Additionally, the FR310XT has an openwater swim modethat attempts to analyze the GPS points of the watch even while worn on your wrist, and come up with a semi-accurate distance. In reality though, while this is a good first step in the advancement towards thatgoal - it simply isn’t very accurate, especially compared to the swim cap method.

As far as in-pool options go, your best bet is either the Swimovate Pool-Mate Pro, or the FINIS Swimsense, both of which have downloadable capabilities (there are other devices out there, but none have the ability to download the data). I recently did a shoot-out between the two of them to help you decide which might be the best fit for you.

Question #2: Best bet for trail running watch with altitude?
From Grace-

"A sales associate from a running store in Bloomington, IN recommend me to contact you since he does not have an answer to this question: What is the best sports watch for trail runner? On top of heart monitor, distance, speed, what I also care is the elevation GAIN during the whole run. It will be even better if all these info can be seen directly on the watch instead of plugging into the computer (do not have a additional time for this one more step)."

The biggest item on your list is definitely the altitude piece (since most watches do the remaining items). Within that space you essentially have two options: Watches that have a barometric altimeter (such as the Polar devices like the RS800CXor the newly announced RCX5) or devices with GPS-based altimeters (such as the Garmin Forerunner line).

Since I’m most familiar with the GPS-based ones as far as running watches go, I’d recommend looking at the FR310XT - which covers what you'd want to do.With the FR310XT you'd get some 20 hours of battery life, ideal for anything that you want to go rather long on (like an ultra). The FR310XT gives you pretty detailed historical (and live) stats on your workout- so you wouldn’t necessarily need to plug it in to see the details. Though plugging in gives you tons more data to analyze if you want to.

One note is that while the much smaller FR60 is great for many runners looking to avoid GPS,it lacks an altimeter, so it doesn’t quite fit your bill. Just something to be aware of.

Question #3: Auto-Pause, Running and Races (and why your distance might be short)
From Bob-

"I too ran the National Half-Marathon but my Garman was almost 2 minutes faster than the official time. I am guessing that it was the tunnels and that My Garman FR305 went into "pause" when it lost the signal in the tunnel. My distance was right on, but the time was fast. Have you had that problem in tunnels before? If so, how did you work around it?"

It does sound indeed like auto-pause was the culprit here. In your case, your distance would have been pretty close because within a given activity the Garmin will always 'connect the dots’. Meaning, if you pause the watch, travel500 miles away, and then start it- you’d actually have some 500 miles of extra distance included in your workout. In your case, you did a much smaller variation of that.

To solve that I generally recommend that auto-pause be turned off- especially in a race situation. While I do find auto-pause useful in some inner city cycling situations, I think that in general for most folks training with longer sets that auto-pause just gets in the way sometimes.

In my case on that same course because I've got an ANT+ footpod on it actually goes ahead and switches over to that during a tunnel or any period w/o GPS. The way the Garmin units work is that it has a simple condition of "When GPS speed = zero,usefootpod speed instead", and vice-versa. You can alsoset priority for either speed source, should you want to.

(Side note: If you’re unfamiliar with GPS accuracy and race measurement in general, I highly recommend you start here, where I go intodetail on how courses are measured)

Recent Mailbags:

Weekly Mailbag - March 25th, 2011:
- Understanding Elapsed Time and Time in sport files
- Deciding between an iPhone in ANT+ case, and the Edge 800
- Garmin Futures: Vector Pedals and new version of the FR310XT

Weekly Mailbag - March 19th, 2011
- Average Pace vs Lap Pace vs Instant Pace
- Attaching Timex Global Trainer to Triathlon Bikes
- Heart Rate Strap Batteries

Weekly Mailbag - March 9th, 2011
- How Auto Pause Works
- ANT+ Enabled Phones
- How the Tunebug Bluetooth Helmet Music System works

You can find all past Slowtwitch Mailbags here, and all prior ones here.

[Editor's note: our capable editor-at-large for electronics Ray Maker is the publisher of the online sports tech blog DC Rainmaker, one of the top-ranked sites by Google for extremely in-depth reviews of advanced GPS and Heart Rate Monitors for triathlon, cycling, and running.]