For me, on an airplane trip, the Pros kept eventually slipping out after 30 mins or so. I tried all 3 different sizes of gel, but had the same problem. I don't think Apple have really cracked this.
I have the original Mk1 AirPods with cheap gels and bought the pros as I thought they'd be a worthy upgrade.
After a week, I returned the Pros and kept on with the originals.
My final analysis - AirPod Mk 1s with gels on are absolutely the equal in sound quality to the Pros and they don't fall out of my ears after 30 mins. I can afford to keep both - I just wasn't sold on the upgrade after living with the Pros for a week.
I certainly wouldn't run with the Pros in my ears - I wouldn't trust them to stay in.