We have December . I am actually in Poland in my hometown - Gdansk . The weather is not pretty , but the training is being done in all conditions. For now, do not throw . I think it is too early for this type of training. I do a lot of exercise at the gym , elements to improve the condition , run and even the techniques used Nordic Walking . At the beginning you have to make the basis for further training more profile for javelin . Winter is just such a period. If You are strong , efficient, stretched and fast then it is much easier to go back to training with the spear and throw really far . All exercises should be done in moderation. Doing a lot of them in different parts of the muscle . Degree increase weight and quantity of the series. Winter is also a period to build muscle mass and power of course . It is important that during the exercise on the major muscle groups not forget about the smaller deep muscles that hold the spine example . A healthy body can do anything !