Diamondback 510T Operating Instructions Manual page 24

Exercise Information
Folding Mechanism and Locking System
l When you need to pack away the treadmill, Follow these steps.
1. Pull both armrest pins towards you (Located under the handrails), Then fold armrest handles upwards.
2. Hold handrail bar with one hand and pull the level bar up with another hand.
3. Allow the handrail bar to slowly fold down to the treadmill. NO NOT DROP THE HANRAIL BAR.