I have a friend who works in one of the largest warehouses in the world. His job requires constant movement: bending, reaching out, stooping, twisting his torso and more.
Before each shift begins, and after each break, his supervisor holds a brief stretching session for the team to work the primary body joints used on the job. Each stretch is held for a count of 10 seconds.
My friend was astonished when I told him the stretching was useless. Maybe worse than useless because workers might think those stretches prepared their bodies for extending a leg too far or reaching up too high and stressing a tendon (at each end of a muscle) or a ligament (white tissues that connect one bone to another).
The act of stretching should be slow and gentle to prevent stress on the body's connective tissues. Any stretch move should be held at least 30 seconds, or ideally, for a full minute.
Even more important, the body should first be warmed up so the tissues are ready for stretching. The warm-up should consist of 10 or 15 minutes of repetitive movements for all major joints, like swinging arms while using a spin bike or a treadmill to warm up the shoulder and elbow joints. Flexing and straightening the legs with a lazy jog will warm up the hip, knee and ankle joints.
The popular Mayo Clinic site offers similar advice, stating:
"Warm up first. Stretching muscles when they're cold increases your risk of injury, including pulled muscles. Warm up by walking while gently pumping your arms, or do a favorite exercise at low intensity for five minutes. If you only have time to stretch once, do it after you exercise — when your muscles are warm and more receptive to stretching.
"Hold each stretch for at least 30 seconds. It takes time to lengthen tissues safely. Hold your stretches for at least 30 seconds — and up to 60 seconds for a really tight muscle or problem area. Then repeat the stretch on the other side."
Also important: relax while stretching. Never stiffen a joint that you are trying to make more elastic and pliable. That will make you prone to tearing apart fibers in muscles and connective tissue. Also, don't bounce to extend your stretch. Each movement should be slow, extending the stretch slowly to gain a wider range of motion.
Many athletes make the mistake of holding their breath while performing the hard part of a stretch. But this deprives the tissues of the oxygen they need to be responsive and able to perform the task you are putting them through.
You don't need to be doing a workout to stretch. Take 10 minutes before bedtime at night, when your body is already warmed up from the day's activities. Sit down on the floor, spread your legs and reach for your toes. This will stretch your shoulders, groin and hip tissues, and your lower back. Stand up and "crawl" your fingers up a door or wall, which stretches the lats (upper spine) as well as the shoulder joints.
You can never do too much stretching when it comes to the shoulders. They have the most movement of any joint in the body.
Stretching regularly will really pay off as you get older. Instead of the tentative movements of older folks, you will still have the flexibility and range of motion to move like a 20-year-old.