IRONMAN 70.3 Muskoka

Line up with your realistic pace and be intentional in the first 100–200 m: get your breathing rhythm established, settle into clean traffic, and avoid sprinting off the start. Do a quick, controlled warm-up before you enter the water (a few hard strokes, then back to smooth) so you don’t spike heart rate. Once you’re moving, prioritize sighting and staying calm behind the initial surge; if you’re getting kicked, drop slightly back rather than fighting it.

You’re swimming 1900 m in freshwater, with temperature that varies—treat it as a variable you respect. Early effort should feel “comfortably hard,” not maximal, because the bike and run are where you’ll win the day. Expect choppy surface moments depending on wind; with wind from the W at around 4.5 m/s, keep your head position steady and shorten your stroke slightly if you feel your line drifting. Fueling on the swim is typically minimal—focus on execution (position, smooth pacing, efficient sighting) so you can start the bike composed. When you exit the water, get your transition routine done efficiently: re-grab your nutrition plan mentally, don’t stop to “wake up,” and move straight into your T1 sequence.

Your T1 flow sets the tone: dismount where allowed, rack the bike cleanly, and put on kit in the same order every time so you don’t stall. Before you fully surge, do a quick systems check—shoes secured, handlebars comfortable, bottle(s) accessible, and hydration/nutrition ready. For the first minutes, build gradually: let your breathing and cadence settle before you commit to your steady power/effort for the 90 km.

This is a 90 km ride with a profile labeled “unknown,” so your pacing strategy should be conservative early and responsive as the course reveals itself. With wind around 4.5 m/s from the W, treat exposed sections as variable resistance: into the wind, hold your plan rather than guessing; with it, avoid letting speed tempt you into burning matches. Fuel and hydration are the priority—aim for roughly 90 g carbs per hour, about 750 mg sodium per hour, and ~650 ml fluid per hour spread across the ride, not all at once. If your stomach feels “off,” reduce volume per intake but keep carbs consistent; otherwise you risk under-fueling for the later run. Stay smooth and aerodynamic where possible, but don’t chase speed—finish the bike ready to run.

In T2, your objective is to transfer from “bike engine” to “run engine” without spiking pace. Rerack your mindset: the first 1–2 km should feel controlled and slightly easier than you think you should run—tight calves and a heavy stride are normal off the bike, so don’t fight them immediately. Take 30–60 seconds to settle your cadence and breathing before you start making any pace decisions.

You’ll run 21.1 km after the 90 km bike, and that early transition into the run is where most pacing mistakes happen. With air temperatures typically ranging from about 16 to 24.7°C and only moderate heat, you’ll usually have enough cooling to stay on plan—your job is to keep intake consistent so the moderate conditions don’t mask under-fueling. Use the same target fueling framework: about 90 g carbs per hour, 750 mg sodium per hour, and ~650 ml fluid per hour, adjusting based on how you’re coping with heat and sweat rate. Wind can affect how “heavy” the effort feels; into the wind you may feel slower at the same effort, so trust your breathing and cadence instead of chasing pace. Drink consistently at aid where available, and take carbs/sodium in rhythm—small, frequent intakes beat waiting until you’re already struggling.