This is a workout designed for a group to have a bit of fun (type 2 naturally together) whilst working on technique and the alactic/neuromuscular systems.
After a really good warm-up, a minimum of 15 minutes with a build to the top of your aerobic zone, i.e., where your running companions can hear you breathing.
The set itself consists of numbering yourselves 1 to 3 (so that there are 3 groups consisting of 1 or more people) and running at a pace where you can easily hold a conversation. Then group 1 should stop, count to 15 (or time 15 seconds) and then accelerate to a sprint to catch back up to groups 2 and 3. When group 1 catches back up to 2 and 3 then group 2 stops and counts to 15, then accelerates to a sprint to catch back up with group 1 and 3 again and then group 3 stops, counts to 15 and then sprints back to groups 1 and 2. This cycle then repeats…
I would suggest aiming for each group doing 7 sprints, then everyone having 5 minutes recover, then another 7 sprints each group and then a cool down.
I would expect each sprint to cycle to take 45 seconds; 15 seconds of waiting to go then approximately 30 seconds of sprinting. So 7 sprints should take around 16 minutes.