High intensity interval training has been traditionally used as means of improving cycling time trial performance, in fact a large number of research studies have clearly demonstrated improved time trial performance following a period of high intensity interval training. Recent research published in the European Journal of Sport Science (Etxebarria et al., 2013) found that not only do these intervals improve cycling performance, they can also lead to improved running performance with an average improvement of just over 1 minute during a 5km time trial (completed after a 1hour cycle).
About the cycling interval training research
The researchers looked at the effect of short intervals (9-11 x 10, 20, and 40s intervals) and longer intervals (6-8 x 5 min intervals) on cycling and running performance in a group of moderately trained triathletes. The triathletes completed a series of tests before and after the training period to assess the effects of the cycle intervals on both cycling and running performance. Both training interventions led to similar improvements in VO2peak (~7%), mean power (~10%), as well as reductions in heart rate, blood lactate and the rate of perceived exertion during a 60minute cycle.
Following completion of the 60minute cycle the triathletes completed a 5km running time trial. Interestingly it was only the group that completed the longer intervals that had a significant improvement in 5km run time, with an average improvement of just over 60seconds. The researchers concluded that longer intervals are more likely to benefit 5km running performance than shorter intervals. Therefore triathletes looking to optimize training time to benefit both cycling and subsequent running performance may benefit from regularly completing longer high intensity intervals on the bike. It is also worth noting that the shorter intervals also appeared to have a positive effect on subsequent running performance albeit to a lesser effect.
Practical implications for triathletes
The researchers used 6-8 x 5min intervals which is in line with previous research looking at optimum interval length for improving cycling time trial performance. Due to the large volume of intervals (6-8 x 5mins = 30-40mins total interval time), the intensity of the intervals should not be maximal – ideally heart rate should be in the region of 88-92% of bike heart rate max (HRmax) or around your threshold power. Recoveries should be kept short (60-90seconds) and the work intensity during recoveries should be reduced to around 50% of the effort intensity.
Below is an example of a 6 week progression building from 6 x 5mins off 90 seconds recovery, up to 8 x 5mins off 60 seconds recovery**
- Week 1 – 6 x 5mins @ 88-92% HRmax or Threshold power, 90 seconds easy spinning recovery
- Week 2 – 6 x 5mins @ 88-92% HRmax or Threshold power, 80 seconds easy spinning recovery
- Week 3 – 6 x 5mins @ 88-92% HRmax or Threshold power, 70 seconds easy spinning recovery
- Week 4 – 6 x 5mins @ 88-92% HRmax or Threshold power, 60 seconds easy spinning recovery
- Week 5 – 7 x 5mins @ 88-92% HRmax or Threshold power, 60 seconds easy spinning recovery
- Week 6 – 8 x 5mins @ 88-92% HRmax or Threshold power, 60 seconds easy spinning recovery
Ideally your heart rate should remain on the low end of the target range for the first couple of intervals to avoid a drop of in power over the later intervals.
It’s important to note that the researchers suggest that triathletes should benefit from a combination of both long and short intervals and therefore you would be wise to also include some shorter high intensity intervals as well as the longer intervals.
Etxebarria N, Anson JM, Pyne DB, Ferguson RA. (2013) High-intensity cycle interval training improves cycling and running performance in triathletes. Eur J Sport Sci. 2013 Nov 9. [Epub ahead of print]
**As is the case with any interval training program it is important that you have a sufficient level of fitness before undertaking any interval program and seek medical advice if you are unsure.