Many of you may use and think of these terms interchangeably as what you do before you run, workout, or participate in another form of exercise. However to me, they are quite different.
STRETCHING - engaging in an activity that lengthens a muscle from both ends with the goal of improving flexibility locally or globally. Stretching generally involves holding different positions for a set amount of time without moving.
While of course we cannot infer what is happening dynamically from these images, it looks to me like these three individuals are engaging in stretching.
WARMING UP - on the other hand, involves preparing the joints and muscles for the activity they are about to engage in. This can include joint mobility, blood flow enhancement and dynamic lengthening and shortening of muscles. It does not necessarily require joints and muscles to be brought to their "end range"
Again, while we cannot infer movement from a still picture, I think it is likely that this man is engaging in a dynamic warm up, rather than a static stretch.
There are uses for both static stretching and dynamic warm ups, but I am not sure that they are well known. In a case where someone does not have the flexibility required to do the motion they are trying to do, they need to work on static stretching. This generally occurs if someone is trying to do a new sport or movement in their sport that they have not done before. Or, when someone who has been immobilized due to injury is trying to regain motion that has been lost over time. Static stretching helps to lengthen the muscles to get into these new or lost positions.
These athletes likely had to engage in some static stretching over time to be able to achieve the positions shown in these photos. However, unless they are trying to further increase their flexibility, it does not mean that they need to consistently engage in static stretching to maintain the ability to achieve these positions.
This is where dynamic warm ups come in. They help the body to "warm up to" or access positions that they have the capability and the muscle length to get into. Dynamic warm ups generally can include lengthening one end of the muscle attachment, while keeping the other end in a mid-range position. This helps to maintain mobility of the muscle, with less risk for injury at the site of attachment.
Most athletes and recreational exercisers who are engaging in a sport or activity they have done previously can achieve safer and potentially more effective results with a dynamic warm up vs. a static stretch. Some research shows that static stretching prior to exercise actually decreases speed and power output and increases injury risk.
With the exception of rhythmic gymnastics and perhaps some figure skating moves, athletes often do not need to hold or maintain these end range positions in practice/competition, so why are we doing it in warm up?
Want to learn more about dynamic warm ups and whether switching to one may be appropriate for you? Send me an email at firstname.lastname@example.org and let's discuss!