Having a good foundation of consistent mileage, strength training and running technique work is a must before incorporating this intermediate concept to your long runs.

The goal: To take a ’short’ long run (90 minutes) and enhance the benefit it has for transporting oxygen to tissues in your body.
Begin this run with the first 20 - 30 minutes at truly a conversational pace. This should be 65-70% of you maximum heart rate if you are inclined to use a monitor. The next 30-40 minutes should become a honest effort still within in an aerobic or conversational effort range. This would be a pace that is similar to your marathon race pace in the case of recreational and intermediate runners. The final 20-30 minutes cap the run with the effort rising to just below lactate threshold pace/effort. This should present a deep but controlled and rhythmic breathing. Resist the tendency to turn the last 30 minutes into a tempo run and set back recovery for future training sessions.

The benefits: This is a run that offers a deep aerobic stimulus challenging the heart to serve a decent amount of blood to the peripheral tissues in the body for a prolonged time. Yet with the lack of stress above the lactate threshold (here defined as 4.0 mmol/l for most athletes) there is going to be less residual fatigue from this run that the athletes must work through in the training session in the next 24-72 hours. There will still be lactate management benefits to the runner derived from this workout in that would be translate well to marathon and half marathon running for recreational or intermediate level runners.

20- 30 min - conversational (HR- 65-70% MHR)
30 - 40 min- ‘moderate’ aerobic (HR-70-75% MHR for most runners; pace for bLa of 1.5-2.0 mmol/l for most runners)
20-30 min- ‘high’ aerobic (HR-75-80% of MHR or 2.0-3.0 mmol/l for most runners)