we are not necesssarily talking about movement which would be microns if measureable but there are other factors like density of the pitch and extra resilience of grass varieties/synthetics, lack of moisture retention and so on.
I think the training pitches are more likely to be the issue.
Challenge there is timing
- Training Ground was 14 years ago
- Stadium 7 years ago
It's really the last 2-3 years that have been the issue, so unless something changed in one/both of those facilities, they are not the root cause.