NOTES:  The angle between your hip, knee and foot must not be greater than 90°.  I recommend around 85° as a maximum – this will give maximum benefits and minimal injury risk (there is a small risk of over stressing the knee, hips or back).

For beginners, you may not need dumbells – just cross your arms in front of, and against your chest, for stability, or just place them akimbo on your hips.  With your front foot on the bench, drive through your front leg hamstrings and glutes to raise your rear leg up to sit level with the front foot.  Make sure you straighten up at the top, and try not to use the rear leg to assist you by pushing up from the floor (this is very difficult because it doesn’t feel natural and requires mental concentration to do).  Once both feet are up, you have 2 choices about which leg you step back with first.  I prefer to use the same leg that went forward first, before switching legs after multiple reps on the same leg.  Beginners should alternate the legs with just one rep per leg.  How many reps is up to you but you must ensure that you do the same number of reps for each leg and that you maintain a good form throughout.  Note that Dumbbell Steps can also be done whilst wearing a heavy rucksack (backpack), and can also be done effectively if you have a suitable area with lots of steps or stairs.  

Dumbbell Steps are fabulous for warming up, because it is extremely safe (unless you trip on the step), and very low impact.  I always do these first at the start of my gym routines (just after some aerobic activity like fast walking, cycling or gentle jogging).