LAYING OUT A RACEWALK COURSE

There has been recent offline correspondence concerning how to properly lay out and document a racewalk course. These courses, when serious racers are involved, have some characteristics that ordinary race courses do not, as follows:

1) The courses consist of straight lines and turns. Turns are minimized so as to permit the walkers to get into a nice rhythm and stay there as long as possible.
2) Turns are never a single point. They are large radius arcs, either a segment of a circle or offset from a nearby curbline. Cones are used to define the limits of the walkers’ path, just as curbs do on running courses.
3) When arcs define a turn, the center of each arc, and its radius, is located precisely on the course map.
4) When the arc is offset from a curbline, the amount of offset is shown on the map.
5) Racewalk courses are typically short closed loops, intended to be walked several times. This is necessary so that available judges can properly observe the competitors.

I encountered Bob Letson by mail, back around 1980, when I was selling a race pace computer. He was doing the same thing. We had a lot of correspondence, and he was a great influence on me in my becoming a course measurer. I have always thought of him as the best mapmaker I have ever met.

Below you will see a racewalk course he measured. It contains all of the elements discussed above.

You can download the map from the USATF web site by searching for CA02008RS. You can look at it on Google Earth by searching it for “Marina Parkway, Chula Vista, CA” or using the coordinates 32°37’22.85N, 117°05’56.77W.

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Original Post

The details, which Pete described, for creating and documenting smooth turns, may be applied to running as well as race walk events. The 2008 Olympic Trials Women's Marathon course (MA07005RN) used two turnaround points. One of the turnaround points was on a 4-lane road (approximately 40 feet wide). The turnaround was located in the center of the road. The radius of the arc was the width of one lane (10 feet). That turn allowed enough room for the 150 elite women runners to pass each other safely, while the large arc allowed the women to maintain their pace and avoid slowing down.

USATF rules have specific requirements on the distance of the circuit (i.e. loop course) that are used in race walk championships. For race walk events, 10-kilometers and longer, the maximum length of the loop is 2500 meters. For race walk events less than 10-kilometers, the maximum length of the loop course is 1250 meters. No loop courses should be shorter than 1000 meters.
Last edited by justinkuo
Bob Letson is one of the great pioneers of road course measuring and his maps are the best - But the map is not competely correct. He shows the measured line of the arc at the outer edge of circles - that I believe indicates cones.
The map should indciate the cone placement which would be 30cm in from the measured line (arc).
The way I interpret the map, the lines shown are not measure lines at all. They are simply radius lines to show where the cones are to be placed. Bob chose to place the cones with their edges tangent to the locator line. The runner would theoretically run 30 cm from the cone arcs. There are extra cones that lead the walkers toward the arc ends. These need not be located precisely.
Peter
Very good point. But my recent experiences with some measurers of racewalk courses here in the US didn't know the proper measurement and cone placement procedures.
It would be helpful as we move forward to indicate on the map a second radius line.
The map, as it stands, allows the organizer to set up the course without ambiguity. This done, all the walkers need to do is to stay outside the cones. It looks like the map fulfills all our requirements, and better than most maps do.

I don't understand "It would be helpful as we move forward to indicate on the map a second radius line." Where would we add it? The end turns are already defined by radii. The turns in the middle are defined by distances offset from existing curbs, which may (or may not) be circular arcs.

There is an area of possible ambiguity, I agree. The 5.1 m dimension may or may not carry all the way around the arc. This is not clearly spelled out. Since the drawing is not to scale, it is difficult to tell.
There are a number of very detailed race walk course maps on file. This morning, I ran across the map for the "2010 USA Masters 2 KM Course", CA10015TK, measured by Ted Knight, Joe Davis and Dick Iwamiya. I cut and pasted the detail of one of the two turnarounds.

Notice the turnaround was marked with 14 nails. The location of the center of the semi-circle is defined from a fixed object. The radius semi-circle (14.27 feet), is noted as well as the measurement line (0.15 meters out from the nail heads.) It has all the elements you need for defining the race walk course.

You'll want to take a look at the entire map to see the full level of detail that was included. CA10015TK map

Thank you. -- Justin
Here's and article on Race Walk Design written by Ron Daniel (IAAF Level-1 Race Walk Official)

RACE WALK COURSE DESIGN
NOVEMBER 2007
Ron Daniel

Introduction: In this memo, I will describe the affect of tight turns and narrow race lanes on the performance of the athletes and judges in a race walking competition.

Discussion: I was a race walk judge at three international events (RW Challenge, Mexico, Japanese 20k Championship and Pan American Games) this past summer where the 2km loop had 2m radius turns on each end. The Japanese 20km Championship was being used as the test event for the IAAF World Championship in Osaka, Japan.

At the test event, in addition to the 2m turns, the racing lane was 3m wide (a 6m road with cones down middle). This 3m lane narrowed to 2m on one end as the course-reversed direction. The judges had access to a 4m wide sidewalk on each side of the road. The principal problems with 2m turns for the walkers are the inability to maintain racing speed and legal form. With 49 starters, the athletes were also very crowded during the first two laps (8+ for race). The only problem that the judges encountered was staying aware that the sidewalk had a 5-inch curb. In fairness to the athletes, the judges maintained a presence at the turns but did not over-judge the turns.

In a meeting following the championship (test event), the Japanese LOC agreed to increase the turns to 4m radii and widen the one turn lane to at least 3m. There was nothing to be done about the 3m width of the racing lane; this guaranteed very crowded racing throughout most of the two World Championship 20k races.

At the World Championships, the judges encountered a problem not known at the test event. Instead of the 4 m wide sidewalk, there were placed one-meter tall advertising boards one meter from the edge of the curb on both sides of the course (fig.1) for much of the 1km long course. This narrowing of the course for the judges impacts their ability to properly observe the walkers step progression; the difficulty increases as walkers begin to trail behind and the judges are now faced with walkers moving in two directions and the judges are wishing to observe the walkers in the farther lane. Advertising boards also ringed the turns and one was placed in the middle of the turns further affecting the judges viewing.

Figure 1. Advertising Boards on Course

Performance Impact: An athlete’s speed in a turn is affected by his ability to lean into the turn at a sufficient angle. This angle is dictated by the centripetal force a walker or runner must generate to negotiate a curve of a given radius at a given speed. The following analysis was initiated by Dr. Wayne Armbrust (PhD in physics with biomechanics expertise). Table 1 below shows a comparison between the lean-in angle for a 5,000m runner on an indoor 200m track of radius 21.3m, on an outdoor 400m track of radius 36.8m and a 200m runner on an outdoor 400m track.

Table 1.

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.

Figure 2. 20k lean-in, 20 deg.

The most significant problem for the 20K walkers, throughout the test event, was the loss of form around the turn. Fig 3. Some walkers purposely walked a wider turn to try to minimize the problem. For every one meter wide, the walker adds over 3m per turn and after 17 turns more than 50m to the race.

The change to the 4m radius turns for the World Championships allowed the 20k walkers to race to their full potential (Chart 1. Lost time vs. lean-in angle) even though they still leaned in at 20 degrees. The 50k walkers had no time loss while leaning at 15 degrees; however, many walkers still walked wide (fig. 4). Bent knees in turns was noticeably reduced (as viewed on video).

Figure 3. Bent knee form in turn.

Figure 4. 50k Lean-in, 15 deg.

The necessary lean-in angle for 20k and 50k walkers vs. turn radii is shown in Chart 2.
The chart shows that the turn radius would have to be increased to 10m in order for the lean-in to be comparable to that of the 5,000m runner on a 400m track.

While lost time and bent knee problems were reduced on the 4m radii turns, there still exists additional performance impacting stresses. The first is the lateral stress due to the centripetal force required for the turn; this stress is proportional to the tangent of the lean-in angle. The lateral stress increases 3.5 times as the walker leans to 20 degrees versus 6.5 degrees (the lean-in angle of the 5000m runner). This is then coupled with the change in linear

Chart 1

Chart 2

motion around the turn creating rotational forces on the ankles, knees and hips. For example, a walker with a 1.35m step turning around a 4m radius has a 19.35-degree change of direction on each step. The lateral and rotational stresses become cumulative as the race progresses. These stresses directly contribute to the difficulty of the walker to maintain a straight leg in the turn while attempting to maintain speed. By comparison, the 5,000m runner with a step length twice that of the walker, only experiences a 4.2 degree change of direction on each step.

It’s difficult to quantify the affect of the narrow race lane on the athletes. In the men’s 20k race, through 10k there were about 20 walkers shoulder-to-shoulder within 3 seconds of each other. At one time early in the race, one of the men was forced onto the sidewalk for several strides. There is no way to assess the affect of the narrow course on the judges because each judge had nearly the same conditions and as was done at the test event, the judges were somewhat forgiving on the turns, only calling the flagrant bent knee transgressions.

Recommendations: When designing a course, my recommendation is that the turns be at least 5m in radii and the racing lane be at least 5m wide. Then there will be almost no slowing in turns and minimal lower leg stress due to excess lean-in and less crowding on the circuit. Judges should have at least 3m on either side of racing lane in order to properly view and assess the walkers. Advertising boards should not diminish the judges’ viewing anywhere on the course.

Conclusion: I’m well aware of the difficulty in locating a suitable venue for creating a viable racecourse. However, the design of any race walk course should take into consideration the affect on the athlete and impact on the judges. This should be true for any competition but most certainly for a major international competition. While this report focuses on race walkers, the loss of speed in turns is also true for runners.

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Justin,
That's a fascinating report! I have a few questions:
1. Why do racewalkers lean so much?
2. Would it help racewalkers if there were a way to walk the turnarounds in alternating directions?
3. Any observations of how close they can get to cones on a turnaround, and do your observations confirm the directive to compute the course distance at 30 cm outside of the line where the cones will be?
Justin,
Thanks for that fascinating article. I have some questions:
1. Why do racewalkers lean so much?
2. Would it help if somehow they could reverse direction or alternate directions on those turns?
Bob,

1. I do not believe race walkers lean any further than any human or object moving at the same speed. Centripetal force takes over and creates the lean. Imagine a bicycle making the same tight turns at the same speed (9.6 Miles Per Hour.)

2. Yes, alternating the direction of the turnaround would be a luxury. It would certainly help prevent overuse injuries.

3. I can only give you my observations on how close the walkers get to the cones. I have seen cones kicked out of position in both road and track races. I know the cones were nailed to the pavement at the 2010 IAAF Race Walk Cup in Chihuahua Mexico.

Thank you. -- Justin
Thanks for that clarification. I was not reading carefully enough; I thought Ron's article was saying that racewalkers use more lean than runners, but he was talking about runners on standard 200 meter and 400 meter tracks. The bit about torque on each step is pretty interesting though.
Bob Letson once showed me a study he conducted with runners in regard to turning radius. He concluded that courses should always provide the widest possible turning radius because the sharp turns are a real "drag" on running speed, but I would like to find or see the study again.
I do try to lay out a wide-circle turnaround whenever I can but it is a lot of work and requires careful setup and monitoring on race day. More than a few times I've seen the carefully planned circles either just plain not set up as specified, "vetoed" by police, impossible because of illegally parked cars, or inadequately coned when coning team ran out of cones(!). It's always good to have a "fallback" spot turnaround to give an equivalent distance on the spur of the moment.
Bob Letson's article "What is the Radius Actually Run?" appeared in Measurement News #18, August 1986, beginning page 17.

It may be accessed at MN #18