If you are training for IRONMAN Wisconsin or a late-summer IRONMAN or 70.3, this post is for you.
This article is part of a larger IRONMAN Wisconsin training phases series designed to help athletes understand what to train, when to train it, and why it matters. Too many athletes start the season and jump straight to endurance work and miss the phases that actually drive performance. Phase 2 is one of the most misunderstood and one of the most valuable for being strong and faster on race day.
Here at Madison Multisport, we have coached countless athletes at IRONMAN Wisconsin and 70.3 and have seen it all.
Overview: The IRONMAN Wisconsin Training Phases
Effective IRONMAN and 70.3 preparation follows clear phases, each with a distinct purpose:
Phase 1 – Foundation & Limiters: Technique, mobility, injury resilience, and efficiency
Phase 2 – Speed: VO₂ max, neuromuscular work, and top-end development
Phase 3 – Strength: Sustained power, threshold durability, muscular endurance
Phase 4 – Endurance & Specificity: Race-pace execution and fatigue resistance
Each phase builds on the previous one. Skip a phase, and you limit what you can gain later.
This post focuses on Phase 2: The Speed Phase for IRONMAN Wisconsin training.
Phase 1 is your FOUNDATION! Identify your limiters NOW before you load.
As athletes begin their IRONMAN Wisconsin build, Phase 1 is about identifying and addressing limiters.
Need to improve your swim stroke? A 1:1 session with a local coach goes a long way.
Uncomfortable or inefficient on the bike? A proper bike fit is non-negotiable.
Injury-prone as a runner? Working with a PT to clean up movement patterns pays dividends later.
Phase 1 prepares your body to handle the upcoming training. Without it, Phase 2 becomes risky instead of productive.
If you experience pain with cycling now, why would you wait till later when you’re training more?
Phase 2: The Speed Phase for IRONMAN & 70.3 Athletes
Phase 2 is where raw speed is developed before training becomes heavier, longer, and more race-specific.
This phase is especially critical for IRONMAN Wisconsin athletes, where strong bike power and run speed matter more than pure volume.
Who This Phase Is For
We typically see two types of athletes entering Phase 2:
Athlete 1: New to the distance, focused on finishing and having a consistent day.
Athlete 2: An experienced IRONMAN or 70.3 athlete looking to improve performance.
Athlete 1 often undervalues this phase and becomes overly focused on “covering the distance.” They train too easy year-round and never fully develop their swim, bike, and run capacities. These athletes want to RUSH through this phase so they can get to more volume. HUGE MISTAKE.
Athlete 2 usually enters the season highly motivated. This is where we place heavy emphasis on Phases 1–3, because this is where the biggest improvements in speed are made — speed that later transfers into strength and endurance as the season progresses. This athlete commonly wants to do MORE of this block as they know the benefits they receive from it.
How Long Should the IRONMAN Speed Phase Last?
Phase 2 typically lasts 8–12 weeks.
This allows for:
Two 3-week build cycles with 1 week recovery
For most IRONMAN Wisconsin athletes, Phase 2 fits best in late winter to early spring, before longer race-specific work begins.
Intensity Focus: VO₂ Max Training for IRONMAN
The primary intensity target in Phase 2 is Zone 5 / VO₂ Max.
Swim: Faster than CSS / threshold pace
Bike: Zone 5 (VO₂ Max power)
Run: 5K pace and faster
The goal is not fatigue accumulation. The goal is expanding your top-end ceiling so later phases have more room to grow.
Here in Madison, we commonly use HILL Repeats for running to get in our Vo2 Max efforts. You get a HIGHER muscle recruitment and a lower velocity, keeping injury potenial lower.
How Many Hard Workouts Per Week in IRONMAN Speed Training?
This is one of the most important concepts in Phase 2.
Phase 2 works best using a polarized training model:
80–90% easy (Zones 1–2)
10–20% hard (Zone 5)
In practice, this usually means:
One key hard session per discipline per week
All other sessions intentionally easy around 50% FTP or Slower than Marathon Pace
Easy workouts must stay easy. Turning supplemental sessions into moderate sessions only increases fatigue and reduces improvement
Golden Rule in Training. PLEASE REMEMBER THIS
You have to have a next step. If you exhaust your options too early, then you will plateau. You won’t get better. So early season, you should feel like you can always do more. If you exhaust volume and endurance too early, than you have no where to grow. You can only do so much training in certain areas before you plateau or burn out.
Key Phase 2 Workout Examples
Below are example main sets only.
Key Swim Speed Set (VO₂ / Faster than CSS)
16×25 @ :10 rest (3 FAST/ 1 easy)
50 easy @ 1:00
12×25 @ :10 rest (3 FAST/ 1 easy)
50 easy @ 1:00
8×25 @ :10 rest (3 FAST / 1 easy)
50 easy @ 1:00
Key Bike VO₂ Max Workout
5×1:00 @ 105% FTP / 1:00 easy
3:00 Zone 1
5×1:00 @ 110% FTP / 1:00 easy
2:00 Zone 1
5×1:00 @ 115% FTP / 1:00 easy
Key Run Speed Workout
2×3:00 @ 10 sec/mile faster than 5K pace / 3:00 easy
2×2:00 @ 10 sec/mile faster than 5K pace / 2:00 easy
2×1:00 @ 10 sec/mile faster than 5K pace / 1:00 easy
Alternative Hill Workout!
2x1min @ 4% Incline R:1min walk (5k Effort)
2x1min @ 5% Incline R:1min walk (5k Effort)
2x1min @ 6% Incline R:1min walk (5k Effort)
Common Mistakes During the Speed Phase
Training too hard on easy days
Adding extra intensity “just because”
Extending intervals too long
Carrying fatigue week to week
Rushing through Phase 2 out of insecurity to do more volume too early
What Comes Next: Phase 3 – Strength for IRONMAN Wisconsin
Once Phase 2 is completed, training shifts toward strength and durability, where speed is extended into longer, more demanding efforts.
Phase 3 is where IRONMAN Wisconsin athletes begin converting speed into race-day performance.
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