The importance of a training log
Tom De Marco stated, "You can't control what you can't measure", and there is some truth to that for running. Being able to look back on your training history can be valuable. It can inspire you with how far you’ve come, explain a problem you are having (done too much or not enough) or simply allow you to compare one time period with another. Another valuable aspect of recording your training is to share it with others. This sharing forms an important part of your social support network for running. It can provide inspiration and Motivation, as well as allow others to give you advice. You must be careful to avoid focusing on just one metric, such as weekly mileage.It is better to look at multiple metrics, such as distance, pace, Heart Rate, etc.While weekly mileage can be useful it is best to look at longer time periods such as 14 or 28 days, as fatigue is cumulative over remarkably long periods. Monthly mileage must be used with caution as the number of running days various and as most people do their long runs at the weekend the number of long runs can vary in a given month as well. Using a training log that can provide graphs makes it much easier to visualize your training. Over the years I have used many different techniques for logging my training and I have created a comparison at Training Log Comparison.