Championship leader Dan Linfoot started the Oulton Park weekend in style as he beat Alastair Seeley to the best lap in first practice.
The Optimum Bikes Racing rider clocked a 1min 36.524secs to go 0.038secs clear of his rival.
Alex Olsen looked to have shaken off injury woes as he powered up to third place as Ash Beech was fourth and Richard Kerr fifth.
Pirelli National Superstock with Santander Consumer Finance, FP1 result:
1. Dan Linfoot (Optimum Bikes Racing Ltd) 1min 36.524s
2. Alastair Seeley (SYNETIQ BMW Motorrad) +0.038s
3. Alex Olsen (Cumins by Team IWR Honda) +0.233s
4. Ash Beech (Jones Dorling Racing) +0.376s
5. Richard Kerr (AMD Motorsport) 0.519s