IM Workout Design: Strength and Endurance Training Through Four-Stroke Rotation

Introduction

Swimming training can easily fall into the single-mode trap of “only swimming freestyle,” which over time leads to shoulder overuse and muscle imbalance. IM workouts, which combine butterfly, backstroke, breaststroke, and freestyle, are the best tool for balanced training. This article teaches you how to design IM workouts suitable for every level.

1. IM Workout Features

• Four-stroke rotation strengthens the entire body’s muscle groups.
• Following butterfly with backstroke allows heart rate to relax.
• Breaststroke provides room for heart rate recovery.
• Finishing with freestyle maintains a streamlined body position.

2. Beginner IM Workout

3. Intermediate IM Workout

• 600m warm-up
• 4×200m IM (one stroke every 50m)
• 8×100m IM order
• 400m cool down

4. Advanced IM Workout

• 800m warm-up
• 6×400m IM
• 4×50m freestyle sprints
• 400m cool down

5. Practical Tips

1. The butterfly segment should not be too long to avoid shoulder overuse.
2. The breaststroke segment strengthens the lower body and can serve as active recovery.
3. The backstroke segment is the best time for technique correction—pay attention to your body axis.
4. For the freestyle segment, it is recommended to use CSS pace and compare it with the other segments.

6. IM Workouts and Shoulder Health

The butterfly segment is the most likely to cause shoulder overuse. Recommendations:

• Do not exceed 100m of butterfly in a single set.
• After every 200m of IM, do 4×25m freestyle as active recovery.
• Apply ice or compression recovery immediately after training.

After consistently following an IM workout plan for 3 months, you will find that a 1500m freestyle feels “much easier”—this is the sweetest side effect of IM training.

7. IM Workouts and the Heart Rate Mind Game

The biggest challenge of IM workouts is the “heart rate disparity between strokes”: butterfly spikes your heart rate, backstroke stabilizes it, breaststroke has you gasping for air, and freestyle closes it out. During training, pay special attention to heart rate changes within 10 seconds after each transition—this is the best indicator for assessing recovery capacity.

It is recommended to pair this with HRV (heart rate variability) monitoring. If your morning HRV drops by ≥10% for 3 consecutive days, reduce your IM training volume and switch to a pure freestyle recovery workout. Those who follow IM workouts long-term are most prone to overtraining due to the obsession that “I should train all four strokes”—be sure to listen to your body’s signals.

Conclusion

IM workouts are an essential path for advanced swimmers. Doing IM training 1–2 times per week can improve shoulder symmetry and increase heart rate tolerance. Incorporate it into your periodized plan, and your overall swimming ability will level up.

Related Reading

• Individual Medley (IM) Strategy: Energy Distribution Across the Four-Stroke Order
• Swimming Medley Training: Weekly Workout Planning for All Four Strokes
• Individual Medley (IM) Energy Distribution: Strength Planning Across the Four-Stroke Order
• Swimming 200m Medley Energy Distribution: Energy Management Across the Four-Stroke Order