In February, it is still good time for building strength, whether you train swimming, running or cycling = doing triathlon and even you are training just one of the disciplines. And it is also important to lift the real weights… for the power… and for avoiding injuries
If your main race is in the summer; May, June… then the best time of the year is the winter, to build strength into your body and muscles, else you don’t fly, like you were planning, in your summer race Many is still not having strength training as a part of training… and this is wrong…
When the spring is just behind the door, and it is just not yet time to ride your bike outside, use the period well and do some heavy pedaling on your hometrainer. This session can be just one hour, and remember that it can give you more than 1.30 hours on the road. This is because you are all the time working with your muscles; no traffic lights, no toilet breaks… Great sessions. Try a real muscle building session of 10 min heavy gear -5 min spinning and continue as long you feel you can do it all right, and keep your cadence low around the 60 til max 70 rpm!
(you have bad knees, dont do this !)
What about running; go to the forest and hills if running outside, if inside put the incline on the treadmill up and up. Fantastic way to get heavy legs and build power. Try to increase with 1% every km, and keep the tempo… and you will see …
Swimming: take the handpaddles, and do some good series.
And the real weight training… Heavy lifting, short sessions…and believe you will fly on the roads, when the sun starts shining and the weather gets warm, and you get outside. And the good part also is, that you will avoid some unnecessary injuries.
Enjoy your life and training, the spring is just behind the door!