Warm up is VERY important!
However, running slow (or walking) for the first 10-20 minutes IS warming up.
If we’re running a short race (“short” and “race” are both relative to our own personal experience and skill and talent) then it’s a good idea to do a warm-up run/walk before lining up at the start. If we’re going to be waiting at the start for a while, keep moving, just lifting our legs, twisting our torso, whatever we can without hitting or annoying other people standing in the crowd.
If we’re running a long race (“long” and “race” are both relative to our own personal yada, yada, yada – see above) then we probably won’t want to run much more than the race distance itself, in which case, the first 10-15 minutes is warm-up, so start SLOW. Jeff Galloway once said to start a marathon, “painfully slow”…
Remember, if we’ve been training for a race, or a long run, or a marathon, and if we did our training properly, building our “gas tank”, and the last week or at least a couple of days, took it easy, loading our gas tank and saving energy for race day, then our body is going to be anxious to run. we’re going to have more energy than usual, and we’re going to feel ready to shoot off that start line like a bullet!
DO NOT shoot off that start line like a bullet (unless we only plan to run for a very short distance)!
Since we’re going to be anxious, and raring to run NOW, at the start of a marathon, I believe that’s why Galloway said it’s going to seem “painfully” slow, if we’re starting out at the speed we should start at.
Until our body warms up, or adjusts to “running mode”, it takes a lot more energy to move our body (it’s still “cold”). So, if we start at our goal “average” pace, we’re going to be burning much more energy than we have for 26.2 miles of running. We should be saving that energy, until our body warms up and becomes more efficient.
With a good warm-up run, running will become easier after 10-20 minutes (after warming up).
Without a good warm-up run, running will become more of a chore later in the run (since you burned up most of your energy when your body was still “cold”).
But there is little reason, unless you like to do exercises for the sake of exercising, rather than running, and actually moving your body through time and space, to stand around in one place to warm-up… unless you’re waiting to meet someone else to go running with you – in which case, remember That runner probably won’t be warmed up yet (unless they ran or walked 10-20 minutes to the meeting place), so we should let them run slow the first 10-20 minutes of our run.
And one more thing; 20-30 minutes is probably more than enough warm-up, so if we’re running to warm up for a short race, we should not spend all our energy warming up. And we should not start warming up so early that we are cold and stiff when the race begins.