Zero exercise is not enough. Going for a walk every day is probably a good thing. And if you're training for a marathon, you'll be on your feet for a couple hours of hard workouts every week. But what is the benchmark for a human being just trying to squeeze enough healthy exercise into their life? Let's break it down.

Well, folks, we've come to the final day of the March flexibility challenge. How did it go?

A month is a short time. Even by the end of our flexibility challenge, you may not find that you've made a ton of progress. But every little bit helps, and it's inspiring to see the progress of people who have been working on their stretching for years.

Holding a stretch for 30 seconds isn't the only way to improve your flexibility - it's just the way a lot of us are used to. Dynamic stretching is another approach, combining gentle stretches with movements that often challenge your balance or strength as well.

Our past two challenges were all about getting stronger, but this month we're going to do something a little different. We're getting stretchy.

Dear Lifehacker, I've never been very flexible. I can't touch my toes and most yoga poses are a struggle. What are the least stretches needed, and most effective, to improve flexibility throughout my whole body?

You don't have to be flexible to do yoga, although it certainly helps for some poses. But there are plenty of moves you can do even if you have the world's tightest hamstrings.

Video: If you're inflexible, you might feel like there's no point in trying to stretch. But without stretching, how will you ever get more flexible? A session like the one in today's video can help.

If you have back pain, yoga may be the last thing you feel like doing. But after 12 weeks of a gentle, beginner-level yoga program, people in a recent study had as much pain relief as those who did physical therapy sessions. And either type of exercise worked better than doing nothing at all.

Neck pain and poor posture come from a myriad of problems, and looking down at your phone constantly may be one trigger. In her video, Doctor Jo, DPT and a licensed physical therapist, suggests a couple of neck stretches to help counter the effects of all that texting and reading Lifehacker on your phone.

The reasons for feeling discomfort along your back are pretty complex, but too much sitting or staying in one position for too long can be among the modern-day culprits. If your back feels stiff and lacks flexibility (especially in your upper back), try out these stretches from the bendy folks at GMB Fitness.

If you have trouble figuring out the best way to stretch a particular muscle, try this chart that has a huge range of stretches for each body part. The stretches are arranged into easy, medium and hard categories, so if the stretches you know don't quite hit the spot, you should be able to find a good alternative.

Video: If you feel sluggish when you sit down at your desk every morning, this quick mini-workout will get your blood flowing and your brain powered up. You don't even have to get out of your chair.

The hardest part of sticking to a workout routine may be starting, but the second-hardest part is showing up to the next workout when everything feels like fire. You're not off the hook, though! Staying home actually isn't your best plan of action. Here's what to do instead.

Working long hours at a desk, whether you use a computer all day or some other tool to get your work done, can wreak havoc on your wrists, knees and other joints. Here are ten ways you can keep them in good health, and reduce the pain and discomfort your day-to-day may be putting you through.

Ankle mobility is an oft-overlooked weak link, because your ankles and feet help form a stable foundation for stronger, pain-free movement. But how can you tell if your ankle mobility isn't up to par? Try this quick assessment.

Breaking up long hours of sitting with stretching or walking breaks sounds very nice in theory, but putting it into practice is easier said than done. Well, here's a yoga routine that takes you only three minutes to complete. (Plus, you don't even have to leave your desk!)

If you work at a computer, good posture is important, but difficult to remember throughout the day. These three quick exercises help undo some of the effects of slouching at a computer for hours.

You can do the most amazing warm-up, flexibility and mobility routines, but you still spend a ton more time not doing those things, which could literally be a pain in the neck. Whether you're sitting, standing or lying on your side, Adam Bornstein of Born Fitness shares some tips to quickly right your posture.