Their theory was that physical activity would improve the quality of life of those aged 75 and above, and help them lead independent lives. So they developed gentle exercises that could be performed while being seated.

"At the end of 3 months, the participants’ lives were transformed by these activities and they told us that we cannot stop; we must continue our work with them," Muller says.

Their work with the elderly did continue and now some fifty thousand senior citizens across France each week take part in, and benefit from, hour-long collective exercise routines which encourage mental stimulation and social interaction which, in turn, gives the elderly confidence and a sense of well-being.

But it wasn’t all plain sailing for Muller and Ricard. Although they were convinced of the value of their work, they initially had difficulty in convincing the directors of retirement homes and government officials to provide funding for their proposed programme. However, the authorities in the Alsace region eventually agreed to implement their programme in a dozen retirement homes.  But the deal was only for six months and no more.

"At the end of six months, the residents of the homes told us (again) that we had to continue the work because they had benefitted so much from it," Muller recalls. "But what (could) we do? We had no sponsors."

When the managers of the retirement homes heard that the programme was going to be withdrawn, all but one of the twelve homes decided that they would hire Muller and Ricard to continue the work. The twelfth home said it could not participate due to a lack of funds.

The very next day, Muller got a phone call from the superintendent of the twelfth home. "He told me that he was being held hostage by the residents in his office – many of them in their wheelchairs and with their walking sticks - and they would not let him go until he approved the programme for them," Muller relates. "The superintendent then said that he would find the money for it, and so could I please count them in!"

In just under a decade, Muller and Ricard’s organisation, S.I.E.L. Bleu, grew from the 12 retirement homes to 1,600 across 70 departments in France, and started programmes for individuals who live at home and meet at local gyms for their sessions.

The early years weren’t easy. Muller and Ricard worked hard at selling the idea to potential clients, but they found that the best way was to demonstrate the benefits of their programme, even though it meant providing free sessions. To keep costs low, they did the work themselves and improvised equipment for the participants such as using bottles filled with sand for dumbbells.

Muller and Ricard expanded their work and created tailor-made programs to include people with special needs such as Alzheimer’s disease. The benefits were impressive. "Staff at the homes told us that the Alzheimer patients could recognise us and assimilate what we taught them to do, whereas they themselves remained unrecognisable to the patients," Muller says.

‘S.I.E.L. Bleu’ means ‘blue sky.’ It is made up of the acronym S.I.E.L. which stands for Sport, Initiative Et Loisirs (sports, initiative and leisure) in French, and the word and colour Bleu in France is associated with senior citizens.

"We keep our prices low, so that (the programme) is affordable to everyone. If someone needs our services, but can’t afford to pay for them, we will help them find a solution," Muller says.

S.I.E.L. Bleu currently employs 200 staff.  In 2007, its revenue was 6 million euros with a profit of 200,000 euros which is being used to grow the company. Some 80 per cent of the revenue comes from earnings, with the remaining 20 per cent coming from the government and companies whose work involves the elderly. For example, a laundry chain which cleans the laundry of retirement homes contributes towards S.I.E.L. Bleu’s revenue. “These private companies have a great philosophy of channelling some of their profits back to the elderly,” Muller explains.

S.I.E.L. Bleu now provides specialised services such as activities designed for the physically-challenged and one-on-one sessions for the elderly who live at home – a programme called DormiSIEL. Since 2000, they have been working with the University of Strasbourg on the certification of a two-year course for those who are looking for training.

"We believe in prevention," Muller says.  "In the construction industry, for example, statistics show that accidents happen in the first two hours of work. We work with them by taking their workers through a 15-minute exercise routine at the start of the day that prepares them for the work ahead."  They also work with companies to prevent problems that arise from ergonomically-incorrect and repetitive activities.

S.I.E.L. Bleu has come a long way. "My greatest satisfaction is seeing the smile on the faces of the octogenarians, and the fact that we are providing jobs for 200 people," the social entrepreneur says. In spite of his busy schedule managing and developing the company, he sets aside one day a week to work at a retirement home. "No one can take that away from me," he says.

Jean-Daniel Muller recently took part in the INSEAD Social Entrepreneurship Programme at the school’s Europe campus in Fontainebleau. For further information on INSEAD's Social Entrepreneurship Initiative, click here.