Winter is the perfect time to build a training base before any spring races. Focusing on improving your top-end speed with fartlek training can translate well to the 5 km distance and even trickle down to faster times for the half-marathon and marathon. The idea behind fartlek training is to help your body to adapt to various speeds and threshold zones.
Fartlek is a Swedish word meaning speed play. A fartlek session involves a continuous run while increasing and decreasing the speed and intensity for a period of time. Fartlek and interval training has many of the same benefits but the difference is the continuous running between reps.
10 to 15 reps of 90 seconds hard and one minute easy
Although 10 to 15 reps may seem like a lot on paper, the point of this workout isn’t the number of reps – it’s the time on your feet. To get the most out of it, spend the 90 seconds at your goal 5K pace, then the one-minute rest at a slow easy jog pace (for most runners this would be two to three minutes slower than your pace for the 90 seconds). 10 to 15 reps can simulate a 5K race. Your average pace on each rep will give an estimate of your current 5K time.
Runners have the option to make this workout easy or hard depending on their rest pace. The faster you jog your rest minute, the harder the workout will become, as your heart rate will remain high. My recommendation would be to start with a slow jog rest and increase your rest pace as you advance through the workout, depending on how your body feels.
If you are finding that the workout is too hard, even with the slow jog, break the workout in half: two sets of seven reps of 90 seconds and a minute jog (with three minutes jog rest between sets). The purpose of the workout is to maintain your goal 5K pace for its entirety If you are dropping off the pace after six or seven reps, don’t be afraid to add the additional rest to control your heart rate.
This workout is also helpful for beginners learning to run. Run the 90 seconds and transition to the one-minute jog into a one-minute walk, then repeat.