I have said it before and no doubt I will say it again: If pressed for time, don't skip the gym altogether – just shorten your workout. Here is a quick elliptical workout that is only 22 minutes long including warm up and cool down. Using quick intervals makes the workout intense and productive in burning calories. Remember to work honestly within your Rate of Perceived Exertion (RPE) and work between easy (1-3), medium (4-7) and hard (8-10) amounts of exertion. Play with the levels of resistance to find one that feels right for your short sprint. I added two minutes of moving the steps backward to target the hamstrings.


Warm Up
00:00-03:00 Level 3
03:00-05:00 Level 5

Quicky Intervals for 5 minutes
05:00-05:08, RPE 8-10
05:08-05:20, RPE 4-7
05:20-05:28, RPE 8-10
05:28-05:40, RPE 4-7
05:40-05:48, RPE 8-10
05:48-06:00, RPE 4-7
Repeat 4 more times

Recover
10:00-12:00, level 7, Backward

Quicky Intervals for 5 minutes
12:00-12:08, RPE 8-10
12:08-12:20, RPE 4-7
12:20-12:28, RPE 8-10
12:28-12:40, RPE 4-7
12:40-12:48, RPE 8-10
12:48-13:00, RPE 4-7
Repeat 4 more times

Cool Down
17:00-20:00 level 5
20:00-22:00 level 3

Source