Determining go-marks for the 4 x 100m relay is an interesting task. Your athletes can practice only a few repetitions at the full 100m distance before they become too fatigued to establish accurate marks.

As a result, they usually establish their marks based on trial and error, using sprints over shorter distances—unfortunately, at running speeds that seldom resemble a competitive effort. In fact, such shorter sprint efforts may find your sprinters accelerating as they enter the exchange zone, although they would actually be decelerating if they'd run the full distance in a race.

So how can you be more precise in determining the go-marks for your relay runners? Tom Ecker, in his book Basic Track and Field Biomechanics, has devised a formula based on competitive efforts.

**Go-Mark Formula**

Have your athletes run a full-out time trial over 100m. Using assistants, time their first 26m and their last 25m. These times will help you determine their go-marks.

Determine the placement of your runners, then plug their times into the following formula:

G = 75 (O — I)

I

G = Go-mark distance, in feet.

O = Outgoing runner's time for the 1st 26m of his/her time trial.

I = Incoming runner's time for the final 25m of his/her time trial.

The above formula will give you the go-mark for a fast exchange, within 4.5 meters of the end of the exchange zone. If you want a slower (less acceleration distance for the outgoing runner) but less risky exchange, measure the first 21m and final 20m of your athletes 100m time trial and use the following formula:

G = 60 (O — I)

I

G = Go-mark distance, in feet.

O = Outgoing runner's time for the 1st 21m of his/her time trial.

I = Incoming runner's time for the final 20m of his/her time trial.

This formula will result in a baton exchange in the middle of the exchange zone.

**Example**

Here's an example. We'll calculate the go-mark for a faster exchange, using an outgoing runner with a time of 3.8 seconds in the first 26m of the 100 time trial. The incoming runner's final 25m time (in the 100m) was 3.2 seconds.

G = 75 (3.8 — 3.2)

3.2

G = 75 x .6

3.2

G = 14 feet

Your outgoing runner would then begin sprinting when the incoming runner crossed a mark 14 feet before the acceleration zone.

**Be Sure to Test the Marks**

These marks won't be perfect, since timing errors may occur and competition conditions can vary. However, they should give you a good starting point for determining your go-marks.

**References **

1. Tom Ecker, Basic Track and Field Biomechanics (1st Edition), Tafnews Press, 1985.

2. Ralph Mann, PhD, The Mechanics of Sprinting and Hurdling: 2013 Edition, CreateSpace Independent Publishing Platform, 2013.

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