GB Rowing trials: Helen Glover & Heather Stanning lead strong British field

The trials will go a long way to deciding who will be in which boat for the Olympic Games

With 115 athletes, 17 Olympic medallists and just 48 places at Rio 2016 available, it is little wonder the week of the GB Rowing trials is among the most intense on the sport's calendar.

Although selection for this summer's Games will not be decided solely on the strength of a rower's performances across Tuesday and Wednesday, crews that seemed fixed in the coaches' plans could be recast because of one bad or one stellar showing.

Primarily, the trials will help finalise the boats for the European Championships in Brandenburg from 6-8 May - but any rower not included in those crews must confront the unpalatable reality that their Olympic dreams are in serious jeopardy.

The nervousness around the team's Caversham base in recent days reinforces how real that possibility is. "I definitely notice a subtle difference," said World Championship medallist Mark Aldred. "People are getting into training earlier to do a bit more."

How do the trials work?

Regardless of their speciality, all 115 rowers will compete in either singles or pairs races with the fastest 12 boats in Tuesday's respective time trials moving into the semi-finals later in the day.

The top three in those races will contest the finals on Wednesday, meaning the prospect of an Olympic medallist or two being consigned to the B finals - and an especially anxious wait for selection news - is far from fanciful.

"If we're good enough, we'll be in the boat; if we're not, we'll miss out," said Jess Eddie, who competed at the past two Olympics in Beijing and London. "It's pretty intense but it's in our own hands."

Who are the ones to watch?

Seven Olympic medallists will take to the water in a daunting men's pair event - including three who won gold at London 2012 - with Mo Sbihi and Alex Gregory the favourites to win a third consecutive title. However, Andy Triggs Hodge - who will team up with Matt Langridge - could also be worth keeping an eye on as he attempts to equal the British record of 10 trials wins, held by Katherine Grainger.

It is hard to see past the peerless Helen Glover and Heather Stanning in the women's pair, given that the reigning Olympic, world and European champions have not lost a race for well over four years. However, Jess Eddie and Polly Swann, who won World Championships gold with Glover in 2013, will likely provide stiff opposition.

The injury-enforced absence of Grainger in the singles leaves her partner from last season, Vicky Thornley, as favourite.

And in the men's event, Angus Groom will look to build on a breakthrough few months by edging out London bronze medallist and three-time world champion Alan Campbell, who lead a field missing most recent winner Charles Cousins.

The highlight of last season's trials was the three-boat photo finish between Olympic champion Kat Copeland, Imogen Walsh and Charlotte Taylor in the lightweight singles. All three will go again this week for the right to occupy the doubles.

And the lightweight men will have both a singles and pairs event as they compete for the right to man the two Olympic boats - the four and the double.

Where do they stand for Rio?

British crews have already earned Olympic qualification in 12 of the 14 disciplines thanks to a strong showing at September's World Championships.

They have until the World Cup regatta in Lucerne at the end of May to ensure spots in the women's four and quad.