A new pathway spanning the breadth of central Scotland is expected to generate £40 million for communities along the way, according to the First Minister.

Alex Salmond has officially opened the John Muir Way, a 134-mile path from Helensburgh in the west to Dunbar in the east named in honour of the Scots-born environmentalist who is revered across the Atlantic.

Walkers, cyclists and horse riders can enjoy the rocky coasts of East Lothian where Muir played as a child, Blackness Castle on the Forth, Linlithgow Palace, Roman hill forts on Antonine's Wall and the Falkirk Wheel, among other highlights.

The First Minister declared the John Muir Way open this afternoon as a flare was sent up from a RNLI lifeboat, with ramblers, runners, cyclists, flag-bearers and street performers blazing a trail through the first section of the path.

Mr Salmond said: "John Muir was a remarkable Scot - a man whose passion for nature and the outdoors left an incredible environmental legacy that resonates to this day.

"From humble beginnings in Dunbar, his influence spread across the world and his name now adorns parks, glaciers and mountains. His legacy is celebrated in an annual commemorative day in California and his image has featured on two US postage stamps.

"There is no more fitting tribute, in 2014 the 100th anniversary of his death and in our Year of Homecoming, than to officially open the John Muir Way from Helensburgh to Dunbar and take walkers and cyclists through 134 miles of splendid scenery in Scotland's heartland.

"The route will encourage many thousands of people to get out into the outdoors, get some exercise and enjoy the iconic scenery of Muir's country of birth.

"Today's opening is a great way of kicking off the Scottish Government's Physical Activity Awareness Week, which encourages people to take more exercise in the run-up to the Commonwealth Games.

"As well as the health benefits, the new John Muir Way is expected to help Scotland's tourist industry and around £40 million in economic benefits are expected to be brought to the many communities that are connected along the route.

"I am sure the new John Muir Way will be an incredible success and I hope that the many, many thousands of people who will make their way along it in the coming years enjoy a magnificent day out."

John Muir was born in Dunbar in 1838 before emigrating to the United States in 1849.

He helped save the Yosemite Valley in California, was a co-founder of grassroots enviornmental organisation The Sierra Club and successfully campaigned for national parks in America.

Ian Ross, Scottish Natural Heritage chairman, said: "The route is an easy and enjoyable way for the three million people who live in the central belt to enjoy the outdoors every day by foot, bicycle, and even by horseback in some places."

The route has been divided into 10 sections allowing people to complete it in shorter walks or cycles.

It is marked with signs, and a website, book, leaflets and map have been created to give people the information they need to complete all or part of the trail.

The John Muir Way has been developed by Scottish Natural Heritage over three years and the body hopes to encourage more people to learn about Muir and explore the outdoors.

It is also hoped that it will boost tourism and visitor numbers to many towns and villages along the route.