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Garmin Forerunner 305: Indoor Run Intervals

The Garmin Forerunner 305 really shines in the outdoors but this handy little running tool can be useful indoors as well.

The 305 has a workout feature that allows you to set up time-based intervals. No GPS signal is necessary for this sweaty workout!


The setup for a time-based interval workout is fairly simple and shouldn’t take more than a minute or two to configure. Here are a few steps to help get you rollin’.

First you may want to turn off the GPS. When you are indoors there is no point in trying to connect to satellites.

  1. mode button -> Settings -> General -> System -> enter button (on GPS menu item) -> GPS off
  2. Press mode button to back out of various menu pages.

Configure the time-based intervals:

Time-based Intervals Page

Time-based Intervals Page

  1. Go to the time-based interval page.
    • mode button -> Training -> Workouts -> Interval -> Time/Rest Time
  2. Select your desired “ON” Time and Rest Time for each interval.
    • Use the enter button and up/down arrow buttons to select from one of the preset times or specify a custom time.
  3. Select the number on intervals (Reps) you wish to complete.
    • Use the down arrow to highlight the Reps field and then use the enter button and up/down arrow buttons to set the desired value.
  4. Select the Warmup & Cooldown box if you wish the warm-up and cool-down data (time and heart rate) be recorded and the time displayed during this phase. If not, move to the next step.
  5. Select the Done? page item.

Setup is complete!

Time To Run

Now your ready to start running some intervals!

If you did not select the Warmup & Cooldown box during the setup phase:

  • Press the start/stop button whenever you are ready to begin the intervals. The watch will play a little Your done! tune when the intervals are complete.

If you did select the Warmup & Cooldown box during the setup phase:

  • Press the start/stop button to begin your warm-up and display a count-up timer.
  • Press the lap button when you are ready to begin the intervals.
  • When the intervals are complete, the display will switch to a cool-down count-up timer. Select the lap button when your cool-down is complete then the Your done! tune will be played.

Nice Features When Running Intervals

  • At the start of each interval the watch beeps and displays “Run for XX:XX” to remind yourself the length of the interval.
  • At the start of each Rest portion of the interval the watch displays “Rest for XX:XX”.
  • The display provides a count down timer during each interval so you can take a quick glance to see how much time is left.
  • The watch beeps during the last 6 seconds of each “ON” or Rest time, to let you know you have nearly completed that portion of the interval and are about to transition to the next phase.
  • The display provides the number of Reps To Go to help remind you where you are at within the workout.

I Liked It

Last week I used the Garmin 305 for my 4 X (4 min “ON” – 3 min “OFF) hard interval set on the treadmill. I only had to worry about adjusting the treadmill speed from “ON” to Rest pace.

It was like having a coach (without the spitting and yelling) tell you what to do while I focused on doing it. No need to worry about what interval I was on or trying to remember what time on the treadmill is the next phase of the interval.

The brain can start to get a bit fuzzy after a few hard intervals. It was nice to just focus a majority of my energy on running.

Since GPS doesn’t work indoors no distance data is recorded but you can always note the treadmill distance data for your weekly mileage logs.

Be active – Feel the buzz!

David –

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About the author

David Hanenburg David Hanenburg is the passionate dirt-lovin' creator of Endurance Buzz and has been playing in the endurance sports world since 2000 after knockin' the dust off of his Trek 950 hardtail thanks to a friend asking to go ride some local dirt. In 2007 he ran his first ultra on the trails and fell in love with the sport and its people. For more information on David's endurance sports journey, check out the About page.

3 Responses to “Garmin Forerunner 305: Indoor Run Intervals”

  1. on 15 Jun 2009 at 6:49 pm Blaine Moore

    I wouldn’t bother using one on a treadmill (but then, I never do speed work on a treadmill) but when you are on the indoor track in the winter it’s great – in fact, for any speed workout its great.

    You just hit the lap button between each interval, and then you can upload your splits right into your training log without having to type them all out!

    It’s a huge time saver.

  2. on 18 Jun 2009 at 7:56 am David Hanenburg

    Hey Blaine – Thanks for sharing. Intervals on the treadmill are fun…really. 🙂

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