IMO Jimbei hit his ceiling, Most likely did not train during TS as he was waiting for Luffy
All worst gen were training, getting stronger, understanding haki, etc
All worst gen were training, getting stronger, understanding haki, etc
Preskip he was able to stop Akainu's killshot, and he is the strongest Admiral, with the most potent devil fruit. He also took the brunt end of the attack that almost killed Luffy (insides cooked), remained conscious for a bit, and was back on his feet immediately following the surgery. Mind you this was after Jinbei had been locked in level 6 of Impel Down for who knows how long, and fought in a massive war. Not for nothing but Zoro passing out to food poisoning and Killer's scythe attack pales in comparison.