Guys, you've gotta do squats. You don't need to be one of those massive weightlifter-type dudes - squats come in many forms, and a versatile enough so that you can do them without any equipment if you need to. What this means is that there are also no excuses not to do them. You've just got to do them with the correct form, of course.
With your arms out in front or on your sides, and body positioned so that you neck and spine are aligned above feet shoulder-width apart, slowly move down as though you're about to take a seat. Make sure you stay upright and anchor your heels. "Form is everything"!