4 important steps in a proper workout.
Step One: Start with a warm up.
Warm-up is not stretching, as what I had been taught during my school days. It consists of light cardio work to warm up those muscles. Maybe 5 to 10 min of lighter workout at the bike or treadmill.
When you stretch when your muscles are cold, you may end up spraining it.
After the warm up cardio, you may stretch if you wish.
Step Two: Actual Workout
For me, I prefer to do more intensive cardio first. After my muscles are really warmed, I do a bit of weight training.
Step Three: Cool-down- (light cardio)
When you do intensive cardio or weight lifting, lactic acid may accumulate in your muscles. The only way to get rid of it from your muscles- is by movement & circulation- so, just like your warm-up, you do light cardio for 5 to 10 mins.
Step Four- Stretching.
Previously, I never stretch after my workouts. Most of the time I need to rush to somewhere after the gym so I never really allocate any stretching time. And I remember always feeling my knees or thighs a bit tensed. One day, I felt my body needed a stretch and no matter what, I must spare time for it (you must learn to listen to your body).
So I took about 8 min, started with leg and hamstring stretches. Some sun salutation, triangle post, spinal twist, followed by waist and arms stretch. And I FEEL SO MUCH BETTER. My tired muscles do not feel so tensed after workout. It also dramatically reduces muscle ache and tension the days after.
Now, I always make sure I spare at least 5 min to stretch after a workout. Stretching is really important- it elongates your muscles (when excessive workout had contracted it) and it greatly reduce your chances of muscle injuries from workout.