I did my third 4 x 1600 of the season tonight. It was warm, 21 degrees, and minimal wind.
I really like this workout. It can be painful and make me want to quite half-way through it, but somehow, I always seem to finish this workout well.
Tonight, I had my fastest 4 x 1600 in quite some time. Splits: 5:11, 5:13, 5:12, 5:12 – all with a 400 meter jog in 2 minutes.
I find this workout to be one of the absolutely best workouts for me to get in great shape for a 10 km to half-marathon kind of distance. I often do 1 km repeats too, but I think 1600’s are much better, at least for me. It follows the ideas from Jack Daniels, who recommends doing intervals at about 5 minutes at 3-5 km race pace as the optimal way to boost our VO2MAX and get race ready.
If you can only run 1000 or 1200 at around 5 minutes at your 3-5 km race pace, then do that instead. It is important to not go much over 5 minutes, because you start gathering too much lactic acid and the training ends up not being optimal. Remember, we want to train smart and not waste time on things that don’t have a direct benefit.
Perhaps I should go a little bit slower and do 5 of them instead, but I honestly have a mental block after 4 of them. I think 4 is the perfect number!
Now, if you are doing marathon training, I recommend focusing more on threshold type running, and doing much more of it. 5 x 10 minutes at threshold pace, or 40 minutes steady pace is a great way to build stamina for marathons. That, high mileage and specific marathon-pace runs, are the key to fast marathons, in my opinion.