1K interval workout is "The King” workout for all long distance runners!
STRUCTURE OF THE WORKOUT
Warm-up | running at easy intensity for 10-20 minutes
Stretching | light 5 min stretch of the major muscle groups (hamstrings, calves) to restore neuromuscular balance
Running drills | the part of dynamic warm-up – high knees drill, butt-kickers drill, skippings, short 50 meter sprints. Check this video for more ideas for running drills: https://www.youtube.com/watch?v=HvH5WZk0f90 Running drills are important because they warm-up your core and legs musculature and prepare for the following main-set intervals.
Main set | 6-8 times of 1000 meters (hard intensity, at 95% capacity) with 3 minute recovery of slow jogging after each interval. Look below for recommendations on exercise intensity.
Cool-down | easy jog for 10 minutes, to put the heart rate down
The exercise intensity (i.e. running pace), at which you should do this session is usually a speed associated with VO2max (i.e. maximal oxygen consumption). There are several ways to estimate your speed at VO2max. The most precise way is to measure it directly during laboratory treadmill test (but this has a price), however there are several Apps that could calculate your Interval training pace based on your previous race performances (a bit tricky for trail runners!). Check VdotO2 APP (https://itunes.apple.com/us/app/vdot-o2/id977666802?mt=8)
Disclaimer – for beginner runners, interval training at lower intensities (65-80% VO2max) might be as effective for increasing aerobic capacity as training at high intensity. Likewise, beginner runners should take into account possible negative effects of high-intensity training, like greater risk of musculoskeletal injuries.
Physiology behind? The most direct aim of interval training is to improve aerobic power (or VO2max – your body’s ability to uptake oxygen and use it for energy production). VO2max is considered important characteristics for long distance runners. If we look a bit deeper to what we actually improve by getting our oxygen consumption higher with interval training, we:
increase the size and volume of mitochondria (“power plants” of our cells)
improve heart’s ability "to pump" more blood
increase muscle capillary network (thus less stress on capillaries during running) etc.
It is generally accepted that trained runners have to reach intensities of 90-100% vVO2max for optimal adaptation. However, once we start running at vVO2max (Interval) pace, it takes approx. 90 seconds to achieve VO2max (see figure on the right). In other words, it takes time to warm-up your "engine" to reach its maximal capacity. For that reason, VO2max intervals are usually longer than 2 minutes (intervals lasting 3 to 5 minutes are ideal for this particular session). Keeping work-to-rest ratio about similar (e.g. 3 minutes of running and 3 minutes for recovery) will allow enough time to start the following interval fresh thus allowing to maintain necessary running pace during all session.
Have fun training and feel free to comment!