Lipo's and capacity

As Lipo batteries die, do they loose capacity? I usually run 5 min runs with about 2 mins of warm up laps so my batteries are rarely fully discharged. Yesterday I decided rather than charge between rounds, I'd run the same pack for two qualifiers. Late in the 2nd qual, my radio was complaining about low voltage (I have a nomadio set to tell me when they get to 14 volts) so I babied it around the track and never actually hit the LVC but I was darn close. Anyway when I got them on the charger, it said they were at 9% and it proceeded to put only about 3800mAh back in...they are 4900's...does that mean my batteries after 3 seasons of racing are starting to go? Might they rebound?