Even without having to store chakra for 3 years she can heal herself from a very fatal injury by biting herself. She has a jutsu which was able to pin down the full kyuubi and create a barrier which the third couldn't even pass through. Though due to being experimented on her whole life and having to take the back during battles due to being a medical ninja, she doesnt have much skill in upfront 1 on 1 battles. Full blooded Uzumaki shinobi are really amazing unlike the likes of Tsunade and Naruto. Though some would say that there's nothing like full blooded, well Kushina after childbirth, at a very weakened state, had the full kyuubi extracted from her and even after this had enough chakra to hold the kyuubi down and create a very powerful barrier not to let neither the kyuubi nor even the third hokage pass through; she still had little chakra remaining for Minato to pass onto Naruto's seal. Naruto just had half of the kyuubi extracted and cant even flinch; his heart beat stops, that's just bullshit compared to Kushina and Karin. Uzumaki shinobi with red hair are always exceptional, Mito was the first to tame the kyuubi, Pain was the only one Madara saw that could handle the rinnegan, then Kushina and Karin as I have stated above. That's what I just learned........