By now, we all know how ­detrimental sitting is for our health. And of course, we all tend to slouch when sitting at the usual desk chair, and that can lead to back pain.

Standing desks can negate some risk, but standing all day can hurt, too.

The following three unusual chairs offer a sensible middle ground between standing and traditional sitting. All count as active sitting, meaning that they require you to engage far more muscles than with a normal chair—so you can strengthen your core, burn extra calories and maybe even alleviate or avoid back pain.

Each one will take some time to get used to, so plan to feel a bit awkward at first. A good way to adapt to any of these chairs is to sit in one for just an hour at a time for a few days and then gradually increase from there. Here are the best kinds of “active” chairs…

Saddle stool: These stools look a bit like oversized bike seats or saddles on top of office chairs. When you sit in one, it causes your hips to open and feet to spread almost as if you were riding a horse. This can help stave off a host of painful back and hip problems as well as plantar fasciitis, all of which can come from sitting prim and proper with your knees and feet together. When you sit in a saddle stool, your feet will naturally fall at 11:00 and 1:00, with hips rotated outward, which helps reduce stress across the hips and knees. The backless nature of this stool can improve your own back strength by requiring you to keep your core muscles engaged as you sit. However, if you find this too tiring or uncomfortable, you can purchase a saddle stool with a back. Example: Jobri Betterposture Ergonomic Saddle Chair, $199.95. SitHealthier.com

Wobble stool: This stool looks a bit like a bar stool on a sturdy base. The seat will wobble from the natural little movements a body makes when sitting, and this motion keeps your abdomen, back and leg muscles moving as you ­compensate. All of that extra movement may counteract the negative health impacts of extended sitting. Example: Uncaged Ergonomics Wobble Stool, $129. UncagedErgonomics.com

Recumbent chair: A standard chair makes slumping easy, but a recumbent, or kneeling, chair features a seat that slants by about 20 to 30 ­degrees. This makes it easier to maintain good posture and avoid back pain. And because a recumbent chair takes pressure off the lower back and buttocks, it can help sciatic pain, too. Example: Relaxus Recumbent Chair, $170. RelaxusOnline.com

Note: Recumbent/kneeling chairs can be hard on the knees, so anyone with ­arthritis, patellar tendinitis, kneecap pain or a meniscus tear should avoid them. People with leg swelling should steer clear as well, as these chairs may restrict your circulation. For most people, this isn’t a problem, but getting up every hour or so for a short break will make using this type of chair for extended periods more comfortable.