On the Trails
It adds to the challenge, but running fast over softer, less-groomed terrain like bridle paths, trails, or grass can increase agility and athleticism—or your ability to run with the "precise amount of power, speed, and coordination needed for efficient movement," McConkey says.
More: Why You Should Vary Your Running Terrain
HIIT It: Because of the terrain and potential strain on your leg muscles, ease into off-road workouts. Do five 30-second pickups at a moderate intensity during an easy 20-minute run, and build up to 10 60-second near-all-out bursts during a 40-minute run.
From there, progress to running five cycles alternating 30 seconds of all-out running with 90 seconds jogging, then to 10 cycles alternating one minute easy with one minute super hard. Just be careful not to trip.
RELATED: 3 Major Speed Workouts Every Runner Needs
On the Hills
Inclines are a great venue for superfast speedwork. Compared with a flat surface, hills reduce the impact on your legs and limit your range of motion, thereby lowering the risk of strains and pulls. Plus, hill repeats build muscle power, which helps you run more efficiently on level ground, says McConkey.
HIIT It: On an incline, start with three 30-second moderate repeats and walk down the hill for recovery.
When this becomes comfortable, progress to 4 x 1 minute near all-out efforts with a downhill jog and an additional 30 to 60 seconds jogging or walking rest.
Over time, add additional reps, extend effort length up to two minutes, and aim for steeper hills, says McConkey.
More: Hit the Hills for Running Speed
Speed Workouts for Novice Runners
When you're just starting out, any type of interval—even alternating walking with jogging—will challenge your body in new ways.
Gibala suggests incorporating one of the following workouts each week to introduce intensity and boost your speed. (Plus: For more guided workout tips, read our Speedwork Tips for Beginners.)
Track: Run two laps. On the straights, accelerate and hold top speed for 20 meters. Walk the curves.
Trail: Intersperse an easy run with 3 to 4 20-second, moderate-intensity surges.
Hills: Do an easy run that incorporates three 20-second climbs, each one at a moderate effort.
More: Use Interval Training to Hit Your 5K and 10K Potential
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