Having read a large number of blogs over the past few weeks I have noticed a similar trend from those who's daily grind (lets be fair in the summer its hardly a grind?!!) to work. This is that the dark mornings and evenings, the cold weather, ice and sometimes snow has started to impact either the enthusiasm or the sheer ability to use their bike to commute.
I have taken the drastic steps myself of getting the train for part of my journey, others I know have parked their pride and joy in garage for a few months in exchange for the car, bus or train. A few of things may happen when this decision is taken:
1) They start to get lethargic, fat and lazy as they get back into the common trap of using their backside to get to work. For all of who have taken this decision can I suggest you consider 2 things? Ensure you do something to stimulate your brain, not only does exercise improve your fitness it improves concentration levels but also simulates brain waves. Cycling more so as you are not only internalising your own thoughts but having to keep sharp eye out for the nutters in cars, vans and trucks!! Get the scrabble out or do a cross word. Do something though! - If you don't believe me do nothing and see how different you feel when you take up cycling again in the spring?
If you simply cannot get out on the bike make the efforts to keep your fitness up and train indoors. Join a gym for 2-3 months, go swimming or get some weights at home. Personally I suggest doing things you wouldn't usually do. Work on your core (that’s your abs and lower back muscle), work on your general body strength (especially the legs and upper body) by using weights and most of all spend time working on your flexibility.
Working on the above during your off season will work wonders to your performance by increasing speed and power and reducing the likelihood of any injuries. It will also start you in a positive routine for when you do get back on the bike.
2) Watch your stress levels - I find getting in the car aggravates any stress I already have or just adds stress I didn't know I had? The reduced levels of positive chemicals caused as a result of exercise will have a huge impact on your mental well-being.