Stretching is a key component to weight training that is abused by most. As we all know, weight training increases mass and strength. However, the downside is that weight training decreases muscle elasticity. Therefore, proper stretching can prevent diminishing muscle elasticity. Here are some stretches and warm-ups that will prevent injury and keep your elasticity the same.
Push-ups: Though these might seem to be exercises, these can also serve as warm-ups. To do push-ups as warm-ups, make sure that you can easily do ten. If you cannot, do them on an elevated surface. The higher the surface, the easier the push-up is. The push-ups get your triceps ready and they stretch your bicep.
Neck Roll: Simply roll your neck around in a slow controlled manner. Feel the stretch in your neck. This stretch should help a little with your upper body lifting by relieving some stress in the neck. Do this before and after your workout.
Back Bending: Raise your arms up and then lean back. Use only your lower back and not your legs. This stretches your lower back. Your lower back is easily injured so don't neglect this stretch. It may also be helpful for anyone suffering from lower back pain as many Americans are.
Touch Your Toes: This is the most cliche stretch, but it is pretty helpful. Simply stand and try to touch your toes without bending your knees. It stretches your back and hamstrings.
Leg Raising: Lie down and bend your knees. Move your legs from side to side. This exercise will warm up your abdominals. Focus on keeping your back flat on the ground. If this is hard, then use your arms to stabilize yourself.
Shoulder Stretch: Take your arm and then pull it across your chest. This (as from the title) stretches the shoulders.
Hip Stretch: Bring your knee up to your chest and hold. Try to hold your balance. To add another warm-up to this stretch, stand on your tiptoe with the other foot. This simple addition will warm-up your calves. It stretches your hips along with your thighs and glutes.
Side Bend: Sway to one side and hold. Repeat with other side. This will stretch your obliques (the muscles at your sides with make up your abdominals). Your hips are also stretched a little. You can also take one arm and bring t downwards so that you can have a hamstring stretch too.
Quad Stretch: Kneel down and lean back until you feel a stretch in your quads.
Butterfly: Sit down and pull your heels in together. The position should look like a "butterfly". You will feel a nice stretch in your groin. The more you pull your heels together and bring your knees down, the harder it is.
These stretches should mostly be done before and after your workout for maximum results. The stretches in which I specifically said to do before and after should definitely be done before and after. Also, most of these stretches should be held for at the very least, 10 seconds. Remember to hold them in their place and don't bounce back and forth as that will tighten your muscles even more. Once you end your workout with a stretching routine, you will feel... wonderful!