The 400 IM is a test of your power, endurance and speed in the pool. Train for this grueling race with the IMX Pro Challenge Training Plan in the MySwimPro app!
IMX stands for IM Xtreme which, in the competitive swimming world, focuses on the importance of being a well-rounded athlete. This Plan mixes aerobic and speed-focused sets with a healthy dose of stroke and technique work to help you master the individual medley.
IMX Pro Challenge Training Plan Overview

- Workouts: 40 Swim Workouts, 20 optional Dryland Workouts
- Average Workout: 2,200 meters = 55 minutes
- Goal: Train/Race in a 400 IM
Who’s it for? You swim a few times per week, are capable of swimming all four competitive strokes and are ready to take on a bigger challenge.
How does it work? This Plan is designed to take your IM fitness to the next level. Benchmark your skills throughout the Plan with an IMX challenge Workout. At the end of this Plan, you’ll be able to swim a fast 400 IM! Complete the optional Dryland Workouts after your Swims or on days you don’t go to the pool.
Sign up for MySwimPro Coach to unlock this Training Plan! Before you get started, check out these resources:
- How to Swim the 200 IM >
- Why You Should Swim All 4 Strokes Every Workout >
- How to Do a Breaststroke or Butterfly Turn >
- The 6 Most Important Swimming Metrics to Track >

How to Train with MySwimPro
In the MySwimPro app, every Swim Workout and Training Plan is customized to your Skill Level. Head to the pool with confidence, knowing you’re getting exactly the training you need to reach your goals. As a MySwimPro member, you’ll unlock:
- Personalized Training Intervals that are tailored to your speed and automatically adjust as you get faster.
- A SetBar™ that shows your expected swim time vs. rest time for every Rep in a Set. This is a game changer if you’re new to interval training!
- A Workout Scaler that allows you to quickly increase or decrease the distance and duration of your Workout to make it fit your schedule.
- Compatibility with Apple and Garmin smartwatches. Sync your Workouts to your watch for Set-by-Set guidance!
- Detailed Analytics about every Workout, including splits, heart rate, SWOLF score, stroke rate, strokes per lap and more.
- Technique Videos explaining drills for all 4 strokes and dryland training technique, plus educational videos to help you improve your performance.
- A fresh Workout of the Day 7 days a week, 365 days a year.
- The MySwimPro Workout Library, packed with hundreds Swim and Dryland Workouts.
Featured Training Plans

After you finish the IMX Pro Challenge Plan, try these Plans!
Ready to get started? Open the MySwimPro app to get your personalized Training Plan >
2 Comments
I swim with my team 5 days a week, and I’m not getting enough out of my practice. Would this help me get better in the IM, being an advanced swimmer?
Hi there! MySwimPro is a great way to supplement workouts with your team to ensure that you are getting the specific, personalized training you need to reach your goals!