The effectiveness of the workout comes from how much you are willing to put into it. Intervals Best on track, but pitch will work fine. Rest 3 - 4 min between each set. Rest for 3 min between sets. Rest for 3 min between sets.
Boundary intervals Use the edges of the pitch.
Divide team into 5 groups. Put two of the groups in one corner. One group each in the other corners. One of the first two groups sprints to the far corner, tag the group which is waiting there. This group sprints to the next corner, tags the group which is waiting, who sprints to the next corner, etc.