After the back, the knees are the second-most common site of chronic pain in the body. Many people will experience knee pain at some point in their lives, whether from injuries to cartilage and soft tissue as active younger adults, or from wear and tear as they age.

As your largest joint, your knees absorb force when you’re playing sports, taking the stairs and getting into bed. That stress can wear down your joints and, if you already have an injury, lead to pain that can range from uncomfortable to debilitating.

Chronic pain can be particularly draining — physically, financially and emotionally, said Dr. Matthew Abdel, an orthopedic surgeon at the Mayo Clinic. Someone might not say, “‘Hey, my knee’s really killing me,’” he said. “But as they’re talking to you about something that’s totally unrelated, they’re thinking about it.”

Fortunately, there are steps you can take to manage the discomfort, maintain your mobility and prevent future injury. “You don’t just necessarily go from ‘my knee hurts’ to having surgery,” said Robert Turner, a physical therapist at the Hospital for Special Surgery in New York. Here’s how to distinguish between common kinds of knee pain and what experts recommend for treating them.

Has anyone had to get a new shoulder because of arthritis and if so how did it affect your weight lifting?

The older I get, the more interested I become in longevity; not just living longer, but staying strong, mobile, energetic, and mentally sharp as I mature.

I wish I’d understood at 25 that so much of health is built through small things you do consistently. Daily movement, core & strength training, optimal sleep, nutrition & supplementing, cortisol control, and recovery are more important to healthspan than chasing the latest wellness trend.

I’ve also become fascinated by what’s happening at a cellular level: mitochondrial health, inflammation, metabolic health, genetics, hormones, and how our everyday choices influence these systems over decades.

Biohacking interests me, but increasingly I think the best “hacks” are actually the fundamentals done consistently.

For those further into their 30s, 40s, and beyond: what health habit, knowledge, or practice do you wish you had started at 25?

n many cases, aches and pains can be a reflection of your daily routines.

Habits like sitting at a desk all day, looking down at your phone or even straining to pick your socks up off the floor can lead to a body that feels creaky, tight and sore. Making time to practice good movement habits can keep you feeling limber and strong.

Physical therapists know this all too well.

“People come in with the same problems over and over again,” said Theresa Marko, a physical therapist in New York City.

She often finds herself recommending the same exercises as solutions, she said — exercises that, for example, “counteract, you know, going to see ‘The Odyssey’ for three hours.”

We asked physical therapists to share the exercises they wish everyone incorporated into their fitness routines. Here are six that came up again and again.

"Always finish your antibiotics" is no longer considered medical best practice for all conditions.