Thank you for the updates. Here are a few things to implement to get yourself back up to speed (no pun intended):
1. Depending on how much time you are able to ride, make 80% of your volume low intensity/aerobic in nature. If you train with a heart rate monitor this will provide you specific feedback to ensure that you are not going too hard. I know that as a racer you want to get back at it; however, you need to allow your body the chance to adapt and improve.
2. For the remaining 20% of your training on the track, don't complete all out sprints, but rather fragmented motos. With this format you break up your riding time (say 20 minutes) where you ride aerobically for 15 minutes and then pick up the pace for the last 5 minutes. You will push your lung capacity, your eye/hand coordination along with your muscles to gradually step up to the new speed. As you become more comfortable, you can go 10 minutes/10 minutes and then move up to 30 minutes (20 aerobic/10 fast and then to 15 aerobic/15 fast).
Please keep in mind that your desire to get back to where you left off is only normal as a racer; however, your body has to play catch up in several areas: cardiovasular, muscular, neuromuscular, etc. Patience will be the key here.
If your schedule permits, cross training with the Concept 2 rower is a low impact, effective way to improve your flexiblity, cardio and strength all in one workout. For strength training, I would recomend the TRX system because it is so convenient and sport specific (push/pull/balance/mental focus). Please keep in mind that I don't sell either of these products, but rather purchase them myself for my home gym, human performance facilities and my clients - the products work!
One final thing to evaluate is your food and hydration. Eat fresh fruits and vegetables every chance you get and consume half of your body weight in ounces of cold filtered water (Example: 150 pounds x .5 ounces = 75 ounces per day). By doing these two things every day, you will increase your energy levels and speed from the inside out.
Remember, Work Smart-Not Hard!