The Three Lions will entertain Jill Ellis’s side at MK Dons on Friday night.
And the players’ fitness levels were assessed as soon as they met up at the national football centre, under the watchful gaze of Sports Scientist Naomi Datson.
She explained: "We normally test the players three times a year.
"The last time we tested the players was in October. They [were] given a training programme to work on and we re-test them to see whether they have improved.
"We did a number of physical performance tests – speed, jumps, ‘yoyo’ – and we also did some physiotherapy screening and some body composition tests.
"We can see there has been a really good improvement which obviously shows they put in a lot of hard work over the Christmas period, so we’re happy."
Mark Sampson’s side were also required to do some strength and conditioning work ahead of their first football session on Monday afternoon.
Datson added: "Between now and the USA game obviously the focus will be on football, so the players have got a gym session in the morning and the rest of the time we’ll just work with the coaches to make sure that the [training] intensity is right."
Tickets for the USA match are priced £5 for adults and £2.50 for children. A family ticket (two adults and two children) is available at £10 and group booking discounts apply.
Tickets are available via www.mkdons.com/tickets
Goalkeepers: Karen Bardsley (Manchester City), Siobhan Chamberlain (Arsenal), Carly Telford (Notts County)
Defenders: Anita Asante (Malmo), Laura Bassett (Notts County), Gemma Bonner (Liverpool), Alex Greenwood (Notts County), Steph Houghton (Manchester City), Alex Scott (Arsenal), Casey Stoney (Arsenal), Demi Stokes (Manchester City)
Midfielders: Karen Carney (Birmingham City), Katie Chapman (Chelsea), Fran Kirby (Reading), Jade Moore (Birmingham City), Jordan Nobbs (Arsenal), Jo Potter (Birmingham City), Jill Scott (Manchester City), Fara Williams (Liverpool)
Forwards: Eniola Aluko (Chelsea), Jess Clarke (Notts County), Lianne Sanderson (Arsenal), Jodie Taylor (Portland Thorns).