An important part of being a runner is keeping a total for the number of miles/kilometres you run each week or your weekly mileage. The question I asked myself was “can you replace runs with swimming and cycling?”, and if you can, what do they contribute to my weekly mileage total?

The primary reasons for measuring your weekly mileage total:

  • How am I doing with my mileage?
  • Am I over-training?
  • When doing repetition or interval training, a good rule is to never exceed more than 10% of your weekly mileage in a single hard training session

In my situation, I lead a pretty busy life which involves a full time job, family commitments, coaching, helping to organise a running club and fitting in my training. This means I can’t always fit in everything I’d like to for my training.

My training week normally consists of approximately the following:

  • 5kms of swimming
  • 120kms of cycling (in summer)
  • 50kms of running (3 x tough running sessions, 1 x long run)

The 50kms is a lot less than I’d like to be running. If I also follow my own rule which states that I shouldn’t perform a single tough training session of more than 10% of my total weekly mileage, this would mean one of those sessions wouldn’t consist of more than 5kms. This is a lot lower than I need.

So how can I add to my weekly mileage using the swimming and cycling I also do?

Conversion Ratio

I’ve applied the following rule to my swimming and cycling training to supplement my total mileage:

  • 1km of swimming = 4kms of running
  • 4kms of cycling = 1km of running

The reason for this is:

  • Swimming is a very aerobic exercise that puts my heart rate into a zone that is a lot higher than my easy runs
  • Cycling is generally a lot easier to do big miles due to the ability to recover, i.e. you might spend 30 minutes going up a hill but the down part nearly involves no effort

So each of the disciplines counts towards my weekly totals as follows:

  • 5kms of swimming = equivalent of 20kms of running (5kms x 4)
  • 120kms of cycling = equivalent of 30kms of running (120kms / 4)

Those extra totals then take my weekly mileage up to approximately 100kms per week. This is a good number for mere mortals who have a busy life!

This then allows me to have my tough sessions up to 10kms of repetitions and 10kms of intervals which is more in keeping with the requirements I have for my running training.

So use this rule next time you’re thinking about your running and the number of miles/kilometres you’re running.