Descending tempo fartlek: Begin this session with a 5:00 interval at roughly your anaerobic threshold (or close to your half marathon pace). The recovery is then a very easy jog, for half the time of the piece just completed (in this case, 2:30). Then run a 4:00 piece slightly quicker than the 5:00 (your rest is now 2:00), then a 3:00 piece a touch quicker (followed by 1:30 recovery), and finish with a 2:00 piece (1:00 recovery), and a 1:00 interval. The final 2 two pieces of this fartlek should be working into the "current 5K fitness" range. For more advanced, higher mileage athletes, you can begin with a six- or seven-minute piece, and go all the way down to one minute.
Downcycle fartlek session: Put simply, downcycles are pick-ups where you begin a bit slower and finish faster. After warming up, run a 2:30 pick-up beginning with the first 30 seconds only five to 10 seconds faster than your normal training pace. Then, each subsequent 30-second block should be a touch quicker than the previous, with the final 30 seconds (from 2:00-2:30) being at or slightly faster than your 10K fitness. After you run the 2:30 second piece, take 90 seconds jogging easily and run another the same way. A good plan would be two sets of 3 x 2:30 with a full 3:00 recovery between sets (each set will be 10:30 in length, including the rest. Add the 3:00 set break and the entire workout is 24:00).
Workout Tip: Begin more relaxed as you start the fartlek. As with long runs and other types of running workouts, fartlek workouts are far more effective and enjoyable when starting easily and finishing well.
More: How to Burn Calories Fast with Interval Training Workouts
Sharpening Fartlek
As you enter the final three to four weeks prior to your more important races, it is important to stress both biomechanics and physiological efficiency. Fartlek workouts can be just as effective as the track when working on your speed element. Try one of these options.
Option A: After a proper warm up, run three sets of 60 seconds at 5K effort, followed by 30 seconds a touch quicker than the 60, and finally, 15 seconds at top-end speed. For recovery, take a very slow jog, or even walk 1:30 to 2:00 after each of the quicker surges, and up to 4:00 between your sets.
Option B: Over the course of an easily-paced run, implement seven to eight 45-second acceleration fartleks, where you start moderately for the first 15 seconds, a bit quicker for the middle 15 seconds and run the final 15 seconds at close to your top-end speed.
Workout Tip: Be well warmed up. These quicker, sharpening fartlek workouts can be lots of fun; however, because they're the most intense and quickest of the lot, they also pose the greatest risk for soft tissue tweaks. Be certain to get in an effective 15- to 20-minute warm-up prior to engaging any quicker running.
Fartlek workouts can be implemented throughout the course of your training and racing year. From early season base training to race day, proper fartlek work will add spice to your weekly training and help you elevate your fitness toward your targeted events.
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