Taper, or tapering, refers to the reduction of exercise before a race. Tapering is believed to be essential for best performance and can take from as little to a week to two or three weeks.
Tapering for your race is one of the most important parts of your preparation. When the gun goes off it is important that you have some fire and the way to find that fire is to ease off the training in the days, and weeks leading up to the race. Taper for approximately the same amount of days as the length of the race. Try not to fit in any last minute rush miles or long runs, you will be as fit as you will get. Resist temptation to modify your taper based on feelings of being edgy from excess energy and if you feel fat during tapering don’t panic, these are normal feelings so don’t fast or miss meals, as it is crucial to eat enough to maintain energy and health. Resting the muscles allows them to store more carbs for the marathon effort and in conjunction with tapering, fuelling with carbs will saturate your muscles with glycogen to help power you past the Wall. This includes carbs consumed in the day going into the race, on race morning and on the run.
So the reason you may feel lethargic and slow is because your glycogen stores are (and should be) continuously full because your low training load isn't depleting them the way it does when you are training hard. You have also become accustomed to lots of activity so when you cut your activity down it does make you feel somewhat weary at times. As I said eat carbs still and protein, drink milk before you go to bed and stay away from people who have colds. Try to drink at least 2 litres of water a day in the final week before the race, it's helps keep the glycogen in your muscles.
You don’t have to cut back on all your activities but it's no use cutting back on the running to substitute it with gardening or cleaning the house or walking around the shops. These activities all require energy and strength and so need to be cut out a few days before the race. Don't jeopardise your chance of running well on race day because the lawn needed mowing or weeds needed pulling up. A few more days of grass growth or dust in the house won't do anyone any harm. So continue to follow your training plan and doing a final speed session the week before the race will finely tune your sense of pacing, as I said earlier you need to still have fire in your muscles. Don’t change your pacing for your final week to running slowly as this could make you feel even more sluggish and alter your running form. This final week is a good time to do a few short runs so 3 or 4 miles at race pace.
Plan to use the time for activity that is going to benefit rather than hinder. If you are used to getting a massage you should schedule time for this (but not if you don't normally have it done). You could also schedule in some flexibility work or yoga, if you are used to it. If the activity is relaxing and not something new to you it may be of added benefit.
Give yourself the best chance you can by taking it easy with plenty of relaxation for a few days leading up to your race and get plenty of sleep. Tapering can be the most dangerous period of the entire training programme. Your body and mind are well rested and peaking for a top performance; it’s hard to hold back when you feel so good but rein yourself in, don’t run too fast or too far otherwise you could blow the entire 12 week build up (or even longer).
Start thinking about the race itself and prepare yourself psychologically, think about how you are going to cope with pre race anxiety, how are you going to maintain concentration whilst racing and running through discomfort and fatigue, start visualising your race, how are you going to break it down?
The last few weeks of the training plan are a guide only, you have done the hard work so if you reduce your miles in this time it will not make any too much difference, it is better to be slightly under prepared than have OTS (Over Training Syndrome). If you are feeling tired or have niggles then don’t get hung up on the plan, just reduce it slightly.