The intensity and duration of the work intervals and the length of the rest periods dictates the training response. Very short, all-out bouts of work coupled with longer rest periods are used for speed and speed endurance development.
Short, very intense work intervals with short rest periods will predominantly tax the fast glycolytic energy system. Conversely, longer, lower intensity exercise bouts and short rest intervals can be used to develop aerobic endurance.
Interval training parameters
Rest intervals are a critical component of the interval training program design. From the chart above, you can see that in order to stress the aerobic system efficiently, short rest periods are incorporated into the session. The opposite is true for speed development.
Research has shown that long rest periods (i.e. 1:12) result in low concentrations of lactic acid accumulation is low, increases in stroke volume are minimal and improvements in VO2 max are not seen. The opposite occurs when short rest intervals (i.e. 1:1 or less) are adopted (2,3).
Very short rest intervals are associated with high levels of blood lactate accumulation. This effects neuromuscular control and can negatively impact speed development. Because speed training requires maximal effort and a high quality of work, longer rest periods are more appropriate to allow the athlete to recover between work intervals. In order to enhance aerobic endurance and increase VO2max towards its upper, genetic limit, interval training should consist of 3-5 minute work bouts with a 1:1 work to rest ratio or less. The intensity should equate to 90-100% VO2max (1). This would be suitable for endurance events such as distance running, swimming, rowing or cycling for example. It could also be used for endurance development in multi-sprint sports such as rugby.
Interval Training Sessions For 10-km Runners
The training sessions in the table below are designed to improve the oxidative energy system the most predominant pathway in this type of activity.
