You carry out a Vo2 sub max walk test on your client and you find her Vo2 Max is 35 ml.kg.min, she weighs 220 lbs (100 kgs)
This tells me her maximum amount of calories she can burn per minute is 17.5 kcals per minute.
If I exercise her at just 50% of her maximum ability she will sustain just under 9 calories (8.75) for each minute of exercise.
She exercises for 30 minutes at this level she will have burned 262 calories. Her fitness capacity is average and her V02 Max tells me she is not fit enough to run.
Even at a slow running speed of 6 mph, this would require all of her energy conversion ability as being able to run you need some reserve and she has none.
A walking programme even at the fastest speed of 4mph would use less than 40% of her ability so she could certainly engage in a brisk walking programme.
However, I would probably want her to combine a walking with what I call a tabbing session which will gradually give the ability to become fit enough to jog at the 6 mph.
To achieve the 50% intensity target during a session, I would put her on a progressive tabbing programme whereby she started out with a target of consistently covering 2 miles in 30 mins (this will be fairly comfortable for her given her V02 Max, and a good starting point to get her out exercising consistently) I would set the programme to increase her distance to 2.5 miles over a 4-6 week period based on feedback.
This would mean she was exercising at a speed of between 4 and 5 miles per hour, at an intensity of between 40 and 70% of her ability.
She will burn 170 calories at 2 miles in 30 minutes and progress to 280 calories at 2.5 miles in the same 30 minutes.
To finish off, I would of course round off her program with mechanical and structural training.
All this JUST from knowing her Vo2 Max!!!!!