Stack height is the amount of material between your foot and the ground. Modern running shoes have got taller, with more cushioning. That helps on the runs but can hurt on the stations.
High stack
- More cushioning for runs and landings.
- Can feel less stable on wall balls, lunges and sled pushes.
- Soft foam can compress unevenly under load.
Low stack
- More stable and closer to the ground.
- Better feel for lifts and squats.
- Less cushioning for 8 km of running.
Foam softness
A high stack of firm foam can be more stable than a lower stack of very soft foam. Softness matters as much as height.
Base width
A wider base improves stability, even with a higher stack. Look at the shoe from above and behind.
For hybrid racing
A moderate stack with a stable base is a common choice. If you are a strong runner, you might go higher. If stations are your strength, lower.
Test it
Do wall balls and lunges in the shoes, not just a run. Do you feel stable in the bottom of the squat?
Related
Heel-to-toe drop explained and how to choose a shoe for HYROX.