Increase Speed with Intervals

Ever wonder why you cannot get any faster? No matter how many kilometers you add to your run?  Adding the extra distance may not be what you need… Intervals could answer your dilemma.

Intervals are used to increase ones maximal aerobic capacity (VO₂max) and anaerobic metabolism.  Why would I want to increase my anaerobic metabolism when endurance running is based primarily on sustaining aerobic metabolism? If you increase your anaerobic metabolism, you increase the amount of stored energy (ATP, PCr, and glycogen) in your muscles for times when your muscles are in times of oxygen deficit.  Not only will it increase your anaerobic metabolism, it will also increase your exercise economy and your lactic threshold allowing you to sustain a higher intensity for a longer duration without a large accumulation of lactic acid from working muscle. 

Below is a figure of my heart rate during a 50 minute continuous interval training session. My work to rest ratio was 1:1 where I continuously ran at 3% grade, but every 3 minutes I increased my speed from 7.5mph to 9.6mph.  My heart rate never exceeded 185-190 BPM during my interval segments while during my periods of recovery my heart rate was maintained at approximately 160 BPM.  By continuously running during my entire session, I can increase my lactate tolerance after high intensity sprints or hill climbs.  This can be a great advantage during races to ensure a quick recovery after quick sprints or to roll over a hill with ease.

For intervals – different work to run ratios can improve various aspects of your performance abilities.  A work time greater than or equal to rest ratio can increase ones speed and maintenance of speed while increasing lactate tolerance.  A rest time greater than your work time ratio will improve your anaerobic metabolism as you allow for increased replenishment of energy stores.  This interval ratio (rest > work) can increase your running speed and your final kick! 

By incorporating intervals into your program can drastically improve your speed and ultimately your performance.  Just remember, adequate rest and recovery after your training session is required for proper physiological adaptations to occur.