So I have gave up on the long distance running ... I felt great especially when I had an event to aim for and I beat my personal bests but for various little reasons I haven't got back into it after I took a break due to moving.

They say running is a lot of pressure on your joints etc but sprints are a great fat burner... to me it makes sense and I think I'd enjoy not being so competitive with myself over a long distance and go for this. Running I certainly believe helped me slim down along side the gym sooo ....

Has anyone done hiit sprints? Any tips or programmes, sprint apps etc you can recommend?

At least one HIIT sprint session should be performed per week. Six sprints overall, three at 85% capacity and three at 95% should be included in your exercises. There should be a 54- to 60-second break in between each sprint of roughly 10-15 seconds.