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Indoor Training

What Metrics Should I Pay Attention To While Training Indoors?

Indoor training is super efficient—if you pay attention to the right stats and tune out the rest.

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The great thing about indoor training is that it offers triathletes the opportunity to focus on metrics in a safe, controlled setting. Unfortunately, that’s also the worst thing about indoor training—metrics are everywhere, from the bike computer beeping out watts to the treadmill buzzing with pace updates.

“Training tech today can give you a ton of information, but not all of it is relevant, especially when training inside,” says Jesse Vondracek, professional triathlete and coach at Top Step Training. Part of his protocol is helping triathletes figure out what information to focus on and what to tune out. For indoor newcomers, he gives a few training tips:

RELATED: Triathlete’s Guide to Indoor Training

Bike Trainer

No matter what race you’re training for, the ability to ride with a variety of cadences is important for race-day success. “The ability to spin very fast without bouncing is a great way to smooth out your pedal stroke, while low-cadence work can help strengthen joints and ligaments and get them ready for the work that lies ahead,” Vondracek says.

The trainer is the best place to do power-specific work, Vondracek says. “I can be much more exact inside than I can outside.” If you have access to a power meter, at least twice a week follow a workout plan focused on power; set up your bike computer to only show this metric.

Proceed With Caution: Heart Rate
Though heart rate is an important metric, it shouldn’t be the primary focus. “If your heart rate is too high, it could mean that you are fatigued,” Vondracek says. “However, it can also be affected by your training room—if it is too hot, with poor air flow, your heart rate can rise to deal with the circumstances.”


If you focus on one metric, make it this one. Your speed on the treadmill should translate to the same speed outside, with one caveat: “Some treadmills, especially older ones, inflate how fast you are running.”

To compensate for the lack of environmental factors, including wind, Vondracek says “flat” treadmill workouts should be performed at a one-percent incline on the treadmill. “This will give you the most accurate representation of your run fitness.”

Ignore: Calories Burned
In addition to being notoriously inaccurate, the “calories burned” on a treadmill can lead to a false estimation of calorie deficit, making you more likely to justify unhealthy eating habits later in the day.

A Note on Fueling

In a climate-controlled environment, do you really need to worry about fuel or hydration? “I’d argue you need more hydration and fuel for an indoor workout,” Vondracek says. Even though the ambient temperature might be fine, the lack of airflow can make you sweat considerably. With indoor training, there is no coasting, soft pedaling, or riding easy. If you are on the trainer for two hours, you are pedaling for two hours. Since it is more intensive, you burn through more calories than you would outside in the same amount of time.

4-Brick Session

Try this brick that totals a 2:45 ride with 70 minutes of it at threshold, and a 70-minute run with 50 minutes of it at threshold:

60-minute ride with 6 x 5 minutes at threshold, and a 25-minute run off with 4 x 5 minutes at threshold

45-minute ride with 5 x 5 minutes at threshold, followed by a 20-minute run with 3 x 5 minutes at threshold

35-minute ride with 4 x 5 minutes at threshold, 15-minute run with 2 x 5 minutes at threshold

25-minute ride with 3×5 minutes at threshold, 10-minute run with 5 minutes at threshold.