William Sichel and Alan Reid will compete in the Scottish ultra-distance road running meeting at Perth this weekend with the aim of gaining selection for next year's inaugural Commonwealth championship.
Sichel (Orkney) has been one of Britain's top 24-hour runners in recent years and is favourite to secure his place on the Scotland team for the event at Keswick next September.
Reid (Peterhead Running Club), a former Great Britain international, is hoping to do enough to win a place in the 100k team.
The 2009 Keswick meeting, which is also to feature mountain racing, has been given formal Commonwealth championship status with a view to the longer-term possibility of these events being brought within the embrace of the Commonwealth Games.
Lochaber athlete Colin Donnelly's reputation as one of the country's most durable athletes will be enhanced further this weekend when he represents Scotland in the world mountain-running trophy at Crans Montana, Switzerland.
It will be the 20th time the Fort William man has competed in this international competition in its 25-year history.
Donnelly, 46, has picked up four medals during that period, although, unfortunately, none have been gold.
He won an individual silver at Die in France in 1989 when he also picked up a team bronze.
Colin was also a team silver medallist in Edinburgh in 1995 and a team bronze medallist at Valle Di Susa, Italy in 1992.
Aberdeen's Lyn Wilson is another of the more experienced campaigners in the Scotland squad this weekend.
The Carnethy club member was in the side that struck team gold in Alaska five years ago.
Wilson finished fourth on that occasion while her clubmate Angela Mudge won the race and former Aberdeen runner Tracey Brindley finished second.
Robbie Simpson (Banchory Stonehaven) will compete for the Scotland junior team in Switzerland.
The 16-year-old expects to benefit hugely from the experience as he has a couple more years in this age group.