you can re-tool your swim technique…
The tools you see poolside — think fins, kickboards, and pull-buoys — may look like kids’ stuff, but they’re key to improving the various components of your swim. “Drill sets are incorporated in every swim workout that I do,” says Karlstrom. “When swimmers ditch the tools, they’ll want to replicate the feel of that body positioning, which will help them with their technique. You simply can’t recreate that in open water.”
…as you improve endurance.
Of course, the focus is on getting to T1 (the swim-to-bike transition), so endurance is necessary, too. And to that end, Karlstrom suggests pool-friendly swim interval workouts. “Interval training improves more facets of endurance performance than just long swimming does – there’s a lot of science to back that up.” Find it
the variables are eliminated.
When you’re riding outdoors, lots of things can disrupt your flow — stop signs, turns, dogs on super-long leashes. “It’s not often that you are going to get a stretch of road that’s going to allow you to hit a five- or ten-minute interval hard before you have to stop or slow down,” says Karlstrom. “On an indoor bike, you can do your workouts exactly as they’re planned.”
Ever get doored in the gym? Didn’t think so. “There’s high danger with riding your bike hard and fast in densely-populated cities,” says Karlstrom. “The pure safety factor of indoor riding is huge.”
there’s no slacking off.
Periods of coasting may be a welcome respite, but they’re a waste of precious training time. “On a spin bike or Computrainer, if you stop pedaling, you stop moving, so you always have to keep your cadence up and keep your legs moving, which is very useful training for the neuromuscular system,” says Karlstrom. Find it
consistency is possible.
Recreating workouts from week to week — without, say, a westerly wind interfering — is a huge boon in gauging your progress over the course of the training calendar.
brick workouts are super-convenient.
A bike-to-run brick workout is one of the key elements of a tri training schedule. But it’s a logistical pain — taking it indoors eliminates the hassle of finding a place to stash your run gear, or lock up your bike, says Karlstrom.
you can design your own terrain.
“I live and train in Chicago – there’s nowhere for us to do hills!” says Karlstrom. Problem solved. Find it
the impact is minimized.
Most endurance athletes do their fair share of pavement pounding, which is why Karlstrom swears by the Woodway treadmill. “There isn’t a lot of dirt or grass nearby, so I use the Woodway. It has less impact than a normal treadmill, let alone concrete or pavement.”