IRONMAN 70.3 Boise

Arrive early enough to settle your breathing before you enter the water. If you can, do a quick warm-up on land (a few minutes of arm swings, hip opening, and 20–30 seconds of faster strokes) so you’re ready when you hit the start chute. Get seeded by realistic pace—place yourself where you’ll be swimming your own rhythm rather than constantly passing. In the first few minutes, focus on clean, repeatable strokes and sighting to avoid drifting; don’t chase every surge in the pack.

This is a 1.955 km freshwater swim with water temperature that varies, so start by settling into effort quickly rather than going out hard. With typical Boise conditions, your main “enemy” in the swim is staying calm while navigating traffic—keep your stroke smooth and save energy for the bike. If it’s choppy when you start, shorten slightly and concentrate on consistent propulsion rather than fighting every wave. Fueling during the swim isn’t usually a target—your priority is arriving to T1 controlled, breathing steady, and ready to start moving.

Set up your transition so you can move from swim gear to cycling gear without thinking: helmet on, sunglasses if you use them, then shoes and your usual kit. As you mount, accelerate gradually for the first kilometers—treat the opening part as a warm-up into the rolling profile. Mentally, plan your effort around the terrain: hold back on the first climbs and pick up speed on the flatter/rolling sections instead of spiking power. Have your drink bottles and fueling strategy ready so you can start intake early rather than “catching up” later.

The bike is 90 km with 479 m of rolling elevation gain, so expect repeated changes in effort rather than one long grind. With wind about 4.6 m/s from the N, plan to manage it rather than react—when it’s into the wind, keep power steady and shorten your stride/torque response; when it’s with/side-on, stay composed and don’t sprint just because speed rises. The heat is hot, so start drinking early and keep your intake consistent as the day warms—don’t wait until you feel thirsty. Your fueling target is 90 g carbs per hour, 1000 mg sodium per hour, and about 800 ml fluid per hour; aim to start matching that rhythm within the first portion of the ride and keep it even through the rolling terrain. On climbs and rollers, take in fuel while effort is manageable, and use the flatter sections to recover just enough to maintain your cadence and hydration.

In T2, get your legs moving quickly: re-rack your focus on posture and breathing, not speed. Expect your quads/hips to feel “settled” off the bike—roll into the first steps tall and controlled, then gradually bring your pace up over the opening stretch. Have your first gel/bottle plan ready so you’re not delayed once you’re fully running. Keep the first kilometer calm; the 21 km course is flat/fast, and going out hot will cost you later.

The run is 21 km with only 24 m of elevation gain and a flat/fast profile, so pacing discipline matters more than hills. In hot conditions, the biggest risk is overheating—stay smooth, keep your cadence steady, and use aid stations for fluid early rather than only when you’re in trouble. With the bike already demanding 90 g carbs per hour and substantial hydration, your run fueling should continue without big gaps so you don’t fade in the latter stages. Keep an eye on how you’re breathing: if you’re working hard early, adjust pace immediately because the course is flat enough that it will tempt you to overshoot. If there’s any lingering wind effect from the bike, treat it as something to manage with effort control—not a reason to surge or to slow abruptly.