If you want the front of your legs stronger, which are the quads, you have to bend your knees. Lunges (pick up something off the floor with one foot in front and the other leg behind, with the back leg bent, with the knee close to the floor), squats (sit on a chair and get up without grabbing onto something, or using momentum to get up), and step-ups (climbing stairs, two at a time are effective, just use your legs, and don’t cheat by pulling up with the railing). If you’re not doing any of the above exercises on a daily basis, your muscles will atrophy and you’ll be more susceptible to falls, knee pain, imbalances, and injury.
If you want your lower back and back of your legs strong, you need to bend at your knees and ankles, and hinge forward with a flat back. That’s why deadlifts are strengthening; the problem is that people go too heavy and use improper form by rounding their back.
We don’t get weaker as we get older because of our age, people get weaker because they stop doing the exercises and sports they did when they were younger. Walking is great for the heart and to get outside, but you want to bend and use every single muscle to be fit and healthy, and to reduce pain, stiffness, instability and fractures.
Photo: me, doing biceps curls