The Benefits of Interval Training

Hi all, last night I did a track session of 16 x 400 metre runs with each run starting every 2:05. My average 400metre run was completed in 1:23, leaving 42 seconds to get my breath before starting the next one.

A week ago I ran 8 x 800metres, similar principle with a new run starting every 4:00 and average speed of 3:00 leaving 60 seconds to recover.

My current PB's are 5k 19:22 and 10k 40:57 and I found both sessions tough.

My question is, what exactly does this training do to improve my performance from a physiological perspective? I realise that it teaches my body to move my legs quicker, but with so much information about lactate thresholds, tempo runs, intervals, anaerobic/aerobic conditioning I have been overwhelmed with information that I am struggling to make sense of in my mind as I have been running for only a few months.

I undestand they will be beneficial but I would like to know how exactly instead of just turning upto a track and running them oblivious of the effect.



  • meant to post and then realised i couldnt say it scientifically so gave up!

  • When you train hard your muscles reach a point at which they produce lactate faster than they can use it. As the lactate builds up, the pH in the muscles drops (lactic acid makes it become more acidic) and this leads to fatigue and a drop in power output.

    The point of training in this way is to change your lactate threshold. Working the muscles at or near the lactate threshold encourages physiological adaptations that helps you to use lactate more efficiently, and also helps to buffer against the hydrogen ions in the lactic acid. Doing this means you train yourself to be able to sustain a higher work output for a longer period of time.

    Is that clear? I hope so!

  • Ok so it increases my lactate threshold - enabling me to work at higher levels of effort before lactic acid builds up?

    Also bearing in mind that I run in a group with varying ability levels, surely the sessions are more beneficial to some than others. The pace will be relatively higher/lower than runners corresponding threshold levels so diffrent people will run at my pace and be at varying heart rates. How do I know if the training is geared towards my ability or people who are faster/slower? Or will this speed/rest/distance interval benefit all runners?

  • So you are doing 400m in 1.23  - that equates to a 5.32 min mile ? So a sub 34 min 10k.

    Basically you're working far harder than your 5 and 10k paces - so you're stretching youself.  I'd not worry about the technicalities of it too much. 

  • I realise that Cougie, but I am a massive geek and I like to know the science behind the training methods and the improvements image

  • PhilPubPhilPub ✭✭✭

    I'd recommend you geek out on a bit of Daniels' Running Formula.  It's been a while since I opened the book but I think it's one of the clearer yet detailed summaries of different types of training, including different interval work-outs and their purpose, and how they related to elements of fitness such as lactate threshold, VO2 max, speed endurance, leg speed, etc.

    ..edit... and if you've got £33 spare, why not take up Amazon's suggested offer and throw in Noakes, and Pfitzinger & Douglas as well.  That'll keep you going for a bit.  You'll be in running geek-book heaven!

  • Hi Phil, I'm already at Chapter Three image Maybe I'll understand everything better when I reach the end!

  • I would say that if you are running with faster runners who are presumably running their laps quicker, eg 60 seconds which means they are getting a minute recovery rather than 42 seconds - so the question has to be what is the actual recovery you should be having - I used to do a similar session with some pretty good 800 metre runners and the same thing used to happen - We compromised and if they were doing say 15 times 300 - the slower runners would do 10/12 times -  

  • RicFRicF ✭✭✭

    I do them alone. No compromise ever.

  • Chris

    You'll enjoy reading Daniels and I would strongly recommend Pfitzinger and Douglas as well.

    At those kind of paces for someone with your times, I would say the sessions are more of a VO2 max session, so read up on those first.... (chapter 8 in Daniels
  • Firstly Hi Folks,

    I'm new to the forum but looking forward to discussing running with you all.

    Although its not what Chris Shipley has asked for, I'd say that his performances in both 1/4 mile and 1/2 mile sessions would indicate much better 5K and 10K times than he has listed. I'd expect that a sub 39 10K and around 18:30 5K would be possible based on those sessions.


    I'd say that pacing events might be something to be worked on. Perhaps some work on even pacing might be a good idea and some lower mileage time trials.

  • Thanks for all the posts, lots of things to consider.

    @Jamie, I have only recently taken up running (3-4months ago) and I find these track sessions very testing and most of the runners participating are sub18 5k runners. Hopefully if what you say is true, by successfully completing these sessions it will have a huge impact on my race times.


    I have had suggestions that this session is improving VO2 max and lactate threshold, can it be possible to do both simultanously? Does it depend on heart rate? No wonder I am confused image

  • To be honest, much as I do lactate sessions and other speedwork too I don't get embroiled in the exact science. Obviously doing any form of faster than race pace speedwork is carried out to improve form/biomechanics as well as improve your bodies processing of oxygen/glycogen etc. Basically making you more efficient at pace. For as long as you aren't doing more than two of these sessions a week, you should see some superb improvements. But make sure that the other days are very easy or you will slow your development or cause injury to yourself. 

    What I do know is that when I was completing 8 x 800m with 1 min recovery in under 3mins per rep, i was definitely running sub 40min 10Ks.....probably close to 39 mins. As for 16 x 400s with an average of 42 secs recovery!! Wow, tough session, a proper vomit inducing session!! Even though your rep time isn't too quick (I aim for 75 seconds per rep) I'd tend to max out at 12 reps with 1 min recovery.

    I'll bet that you see sub 40 mins in your next 10K for as long as you pace it evenly. 


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