There are 3 main ways to increase the intensity of your walking - increase your speed, carry extra weight (in a weight vest or backpack - no hand or ankle weights please) or with hills.
Increasing your speed is probably the first step, although at some point you are going to max out your walking speed.
Adding weight is probably not a good idea with a hip injury.
Including hills on your route is probably the best option of increasing the intensity of your walking. A 5% incline burns roughly 50% more calories than walking on the flat.
Nordic walking poles can certainly help take the pressure of dodgy knees (although I am less sure about what they can do for hips), and this helps some people walk faster for longer. Poles can also help build up a good rhythm, and can help you walk faster.
There are some overblown claims about poles burning 20% more calories. If they do help you walk faster and further, then certainly you will burn more calories. But the point is that it is the walking faster and further that burns calories, not just using a set of poles. Perhaps try a pair out, and see if it does help your walking.
Personally, I use poles when hiking on rougher terrain for balance and stability (and also for steep descents), but tend to put them away on easier going as being more trouble than they are worth.
I took a class at my gym a couple years ago. Loved it! I think the poles help you get your heart rate up just a bit more.
You do want to make sure you size the poles correctly. When holding the poles vertically, your arms (fingers to elbows) should be at slightly more than 90 degrees. And then, when walking, keep your arms long and let them flow naturally.
Here in MN, we have the Nordic Walking Queen, who taught the class. Here's how she describes Nordic Walking:
Has anyone used these? What do you like/dislike about them? I usually run, but I have a hip injury (going to physio) and right now I can only walk. I'd like to get my heart rate up higher. Any suggestions are welcome!