Getting pupils to run a daily mile has been a success, according to researchers, despite the fact that most schools don’t do a mile, pupils don’t always run and it doesn’t happen daily.

The study, from Stirling University concludes that despite this, the scheme has been effective in improving the health and fitness of pupils.

Indeed researchers from the University say the flexibility with which teachers are able to approach the Daily Mile is key to its success.

The Daily Mile concept, which was invented by Elaine Wyllie, former head of St Ninian's Primary in Stirling, has become a global success - thanks largely to its simplicity and adaptability, according to the new research.

The same team of researchers, based at Stirling, with colleagues at Edinburgh University and the University of the Highlands and Islands, previously carried out research confirming that the Daily Mile – which involves children taking a 15-minute break from class to do physical activity – improves the fitness and "body composition"of pupils taking part.

The new study is based on interviews with staff at four primary schools in Scotland, two of which had implemented the initiative successfully and two which were finding the process more challenging.

The findings were that allowing the children to walk or jog, as well as run was key, and rather than demanding pupils complete an actual mile, schools tended to aim to ensure 15 minutes of activity. Typically, schools did The Daily Mile three to five times per week – dropping it on days where PE was already scheduled.

The findings of both studies are to be included in a new guide explaining why schools should consider introducing the scheme, and how best to do so.

Dr Gemma Ryde, Lecturer in Physical Activity and Health in Sport at Stirling, said: “This is the first study to explore why The Daily Mile might have been so successfully implemented,” “Our research suggests that this success can be attributed to the simple core intervention components – allowing the children to walk, jog or run; flexible delivery that supports teacher autonomy; and adaptability that suits the specific primary school context..”

The teachers interviewed told researchers about how they had implemented the scheme and the obstacles and benefits encountered during the process. In addition, the scientists recorded information on the schools’ grounds and facilities.

All the schools carried out 15 minutes of activity, with one participant noting that the intervention is actually time and not distanced based, as suggested by the name.

This was perceived as being short enough to not interfere too much with the school day and – if the children were running –then they achieved approximately one mile during this period.

Staff at one school in the study said while they initially had the children completing an actual mile, it took some children too long or was too difficult for them to complete the distance.

Allowing walking, jogging or running catered for all abilities. One interviewee said: “It catered for all abilities… the ones that maybe are a bit slower, because you’ll get out there and some of the kids will just run around and they want to know how many laps they can do. Whereas, you’ve got other ones that are happy just to walk.”

One of the schools which had struggled with introducing activity had tried to implement a Daily Skip, because of a lack of playground space for running. However, the alternative scheme proved “very challenging” for various reasons, including: the cost of equipment; the logistics of managing the skipping ropes; and the skills required to skip, researchers said.

“These challenges, which move away from the original simple design, plus other demands from within the curriculum, meant that The Daily Skip was only happening sporadically, if at all,” Dr Ryde said.

The study says allowing teachers the autonomy to fit the Daily Mile into the school day and and change the route or surface according to factors such as the weather, was also an important factor.

Dr Ryde added: “The Daily Mile appears to have several factors which may relate to its implementation success. These are important considerations for others looking to implement The Daily Mile effectively in their primary school or in other contexts.”

Elaine Wyllie, of the Daily Mile Foundation, said flexibility had always been key to her initial concept: “I am delighted that the research undertaken by the University of Stirling has confirmed that The Daily Mile works best when it is put in place according to our core principles," she said. “Their research has shown that implementation should be kept simple,

“I’d like to thank the University of Stirling for carrying out this work and highlighting that the adoption of our straightforward approach ensures that children can enjoy all the benefits of The Daily Mile.”