Turnaround - Point or Diameter

Do as you would normally do in measuring any course to start. I suggest you use 1609.344 meter as the distance you want to get certified. Take your two rides from the endpoints and compare the two rides then adjust the distance to be 1609.344 meters.

Running around a single cone and making a u-turn is hard on the joints. For this reason a u-turn with a large radius is preferred. The length of the radius is determined by the width of the street that is used and is usually as large as possible.

Once the radius is determined and recalling that when measuring the measurer must measure within 30 cm/(1 ft.). Do as follows to get the distance.

d = 3.14 (r + 0.3)

Once you know the distance the move each endpoint in that distance. This should be shown with a clear diagram on your map for the cone placements.

Gene 1609.344m is all Greek to the Guido Bros - they're Imperial through and through
I measured a half marathon with them one time and it was like the saying about England and America - two countries separated by a common language

Guidos - I think you are looking for this PDF. It should give you the info you need. I would do as Gene says, and use the largest radius you can on the turnaround.

Road race turn-around marks can vary widely depending on the width of the road, number of peak participants sharing the road and the race director’s ability to set it up. In contrast, measuring race-walk courses there is a necessary requirement to make turn-around points with nice wide radius turns. It does not hurt to document a road race turn-around like a race-walk, but often times a single nail in the center of the road works just fine. After the measurement, a race director can always set up a nice wide teardrop turn-around if he or she chooses to.

Two points are always best with the nail as you describe.

I just noticed this conversation. For runners I think a circular turnaround is way better than a point. But "stuff" happens sometimes. Like cars are parked on both sides where you were assured they would be moved, or for a number of reasons the circular turnaround doesn't work out. So I always mark a point, just beyond my circle, that serves as a backup point turnaround. I.e. has equivalent distance as the path around the circle.

At a half-marathon/marathon I was monitoring, I got to such a turnaround only to find NO CONES for marking the turnaround circle. I grabbed a cone and placed it on the spot turnaround and told some nearby officials their job was to instruct the runners to go around the cone.

TN10083MS is the National 5K Racewalk Championship course in Kingsport, TN. I have periodically timed the race and the multiple cone turns work well for the 20 participants with 5 judges in red coats in attendance. If you are not going to be there personally to see that it is set up right, I would go with a single cone based on experiences with what a harried race director will really do.

Oscar

First, if it is a USATF Championship Race walk, it will be pre-verified and will be validated the day of the event. As for turns here a single point should never be used. The course with a single point will make the participants walk longer.

Race walk people understand that he turns must be setup as shown on this course.

As previously mentioned, the optimum situation is to have the largest semi-circle possible but this of course is not always possible. In addition, this is highly dependent on having reliable individuals setting up the course which does not happen too often! This is why the measurer should be onsite and help to set up the course at major races.
A few thing to remember when creating/measuring a turn - around:
- you will need more room on the end side of the turn then the start side for the runners.
- When indicating the landmarks for the turn note both the cone line and the measured line which of course will be different by 0.30m. This difference can be significant in a race walk course.
I usually paint a dot for the center of the radius + a long arrow pointing to the outer edge of the cone line. I will also paint dashed lines for the cone placement

I am not convinced that a large-diameter turnaround will produce faster times than does a single cone.

The single cone does require the walker to reverse direction abruptly, but the large diameter TA requires the walker to walk more slowly around the arc, which loses time.

It's pretty much Holy Writ that the large-arc TA is superior, but I remain unconvinced.

Does anybody have any facts to help make a choice?

From a race administrator's point of view, a single cone is much preferred.

What do walkers prefer?

I suspect that the principal reason for a large-radius turn is to keep the walkers from getting tangled up with each other trying to navigate as close as they can to a single cone. It smoothes the traffic.

There is an study on this bulletin board titled "RACE WALK COURSE DESIGN"

https://measure.infopop.cc/eve/...024070787#3024070787

The article does not address hairpin turns (with a single cone), but may be of interest. Perhaps, one could extrapolate the effect of a hairpin turn from the data on the various turn radii.

In 2007, Ron Daniel (the current USATF RW Chairman) wrote:

quote:

When the 2m radius turn was proposed, we calculated that a 1hr 20min 20k walker would need to lean-in at a 41.5 degree angle in order to maintain his speed; more than 2 ½ times the lean-in angle for the sprinter. During the test event, many walkers were leaning-in at 20 degrees. (Fig 2.) Even so, with a 2m-radius turn and 20 degree lean the walker will still loose valuable time in each turn. During the 20k on the Osaka course there were 17 turns which would result in a loss of 18.5 sec for the 1:20 pace walker and 12 sec for a 1:30 pace walker. This information was instrumental in having the LOC increase the turn radii.

Thank you. -- Justin

I agree with Pete, at least for running events. With a single point turn around, there may be less potential for inaccurate cone placement on race day. Of course, runners may run bit longer, but not less, assuming the single point is properly set up.

Bob's experience with the half marathon turn around is one of many such incidents that inform me that simpler is better, especially when you are not familiar with or confident in the course layout team.

I remember watching Greg Meyer at the Cherry Blossom race in 1983. Going around a single point turn around, He slipped on the damp pavement and fell . I suspect this turn around did not bother him too much despite hitting the ground hard enough to open a bloody gash on his leg. He got up on his feet and set the world record for 10 miles.

Ok for a running event, yes Pete is correct. However, I can't believe it to be the correct way to lay out a closed loop race walk.

If you saw Justin's response it is best not to use a single point on any closed loop race walk in my option.

I'd just like to say that because something may be a little tricky to set up or manage, that doesn't mean we shouldn't do it. I think the research cited by Justin shows that turn radius affects walkers' times AND form (apparently nearly impossible to maintain form on too tight of a turn). Bob Letson, in an article from MN in 1986, argues convincingly that the same is true of runners. Here is the link to MN #18, as provided by Pete in the conversation cited by Justin:
Lesson article
Bob's piece starts on p 17. It's really worth a read (and his accompanying drawings are quite a treat as well). Bob and I talked about this at length during a measurement conference in Seoul in 1984- he really put a lot of study into this question.

I would say, whenever feasible, go ahead and plan for a circle turnaround, with a tear-drop shaped set of cones. Explain it to your cone-setters and your course marshals. But have a backup spot, just in case.

I'm not sure the Guido Guys ever got a complete answer (and sorry if my impression is wrong). I would do it like this:
1. Mark a single point that would be turnaround if it were just a point turnaround (cone).
2. Decide on radius "r" of turn for big circle turnaround. (You have to make sure there's plenty of room to the outside for runners and sometimes, for vehicles).
3. Measure back a distance of (pi x r)/2 from the point you marked.
4. Use a cable or steel tape to draw a circle with the center at your new point. The circle will show where to put cones.

Example, if you want a 10' radius, mark your first point, then mark another point that is (3.14 x 10) / 2 = 15.7' SHORT of the first point. (15' 8" would be good). That point will be the center of your 10'-dia circle.

With the help of Jane Parks and Chairman Gene, the Guido Brothers, established radiused turnarounds. My (probably over) simplification of this process goes something like this:
• The runners (this is not a race walk course) are going to run a half-circle around a point
• The distance around that half-circle is π x r where r is the distance from the center to the edge of the half-circle
• This is added distance as the course was measured between 2 points
• The center of the half-circle needs to be located such that the distance around the half-circle is not added to the distance between the 2 points marking the ends of the measured course
• The center of the half-circle was located π x r in the direction to make the course shorter
• The radius (r) in this is the distance from the center of the half-circle to the runners’ path
• Cones marking the half-circle turnaround were located 1-ft inside this path (r-1-ft)
• This ignores the extra distance run by leaving the centerline of the measured path to get to the edge of the half-circle. In our case we used r=7-ft, the extra distance is negligible

This is not a world, state or town class event and the race director has limited experience. Our instructions on cone locations are pretty clear. I feel that we have done our due diligence in both measuring and explaining. For the fee we were paid and what we were hired to do, we can’t be responsible for any other aspects of this event.

However, while I agree with those who favor a single point turnaround, based on what can go wrong during race day course set-up, I also think that for a 13-lap marathon, the radiused turnarounds provide a better product (CT16019JHP).

Jim Gerweck is correct, the Guido Brothers are not really brothers. In fact, over the years, there have been a total of 5 Guido Brothers, including a woman. Since the combined age of the current (and most prolific) Guido Brothers is nearly 150-yr, we probably won’t be learning to think and work in meters (or is it metres?).

Can you clarify this one point: exactly how far back did you measure back to find the center of the half circle?

We moved it π x r back. The extra distance from the point to point end points run by adding the half-circle is π x r, where r is the radius of the runners' path.

Whoops. Should not that be 0.5 x pi x r ?

I think so, Mike, that's why I posed that question. We are subtracting a part of the route that is doubled so moving the point 11 feet (for example) actually subtracts 22 feet (which is 7 x pi).

What you are forgetting with the radius is the extra 30cm. You can't run on that arc, hence the 30cm is added.

Guido got that right, as I read what he said:

quote:

Cones marking the half-circle turnaround were located 1-ft inside this path (r-1-ft)

Obviously the 30cm must be correctly accounted for either as above, or by moving the centre back an additional 15 x pi cm.

Yes, the 1 foot or 30 cm is not the problem; the problem is that it looks like the center of the half-circle for the turnaround is placed too far short of the point turnaround, such that the course may now be 11' short-- if based on a 7 foot radius. (I assume the cones were placed on a 6-foot radius to achieve this.)

Over time, turnaround points have been frowned upon by runners and race directors alike.
In fact it is very seldom that a race will allow a turnaround at a single cone.
This puts me in favor of utilizing a radius for a turnaround as large as practical as the preferred practice.
BTW, it should be noted that measuring a single point t/a by the manual actually adds 0.94 meters (3 feet plus an inch) due to the runners path being 30cm or 1 foot outside that nail or cone.

About the extra 3 feet--that's right, but for many years just placing that single point was how we did turnarounds. It seems that allowing for the "extra", or 1 foot outside the cone or cones, was introduced when the new specs for race walks came into being.

I get this for walking events when they go around these turns LOTS of times, but do we really want to incorporate it in our calculation of distance for running races-- knowing that we are tossing away one of our "safety factors" for course length?

Just a question. I'm not sure how I answer that myself.

PS on original post for this topic: Guido brothers have resolved the placement of the turnaround in what I think is a good practical way. I'm still hoping they will write about it . . .

The problem is that many race directors will get rushed with a thousand things to do on race morning, and will just say screw it and put one cone down at the center of the circle. So then the 5k course measured to be 5005m will now be 4997.5m long.
Unless you're absolutely sure they are going to cone the radius I don't think it's a good idea.

It's true that RD's can get in a rush and skimp on these things. But it is better for the runners. I'd say if it's a local race that you care about, show up and make sure if you can. Otherwise, maybe Duane's caveat that he puts on the maps can apply. We measure, proper setup is on them.