Most relay time is won or lost in the exchange zone, and the go mark decides it. Put the mark too close and the incoming runner catches up early and has to ease off. Put it too far and the baton arrives late or not at all. The calculator below turns your four runners' 100 m times into a starting go mark for each exchange.
This tool is a guide only. It gives a starting go mark from a sprint model. Real runners react, accelerate and slow differently, so test every mark at full speed in training and adjust from what you see.
Why the go mark matters
When a Hong Kong relay team reset its go marks to the distances the measurements called for, its time dropped from 41.34 to 40.28 seconds with the same four runners.
The same team had been using marks of 7.5 to 8.5 m when 9.2 to 9.7 m was right for their speeds. Short marks force the incoming runner to slow down to avoid running into the back of the outgoing runner.
The exchange has to happen inside the 30 m takeover zone, and officials judge the position of the baton, not the athletes' feet or bodies. A late, safe pass beats an early, slow one.
What you need: each runner's 100 m best (or a recent race time), a tape measure, and a session where the team can practise exchanges at full speed. The marks below are a starting point to test, not a final answer.
Go Mark Calculator
Enter the 100 m time for each leg in running order. The calculator works out how fast the incoming runner arrives, how quickly the outgoing runner gets up to speed, and where the go mark needs to sit for the baton to change hands at the point you choose.
How to use it
- Enter the four 100 m times in running order. Use recent times run in spikes, not best-ever times from years ago.
- Pick where you want the exchange to happen. Later is faster, but leave a few metres before the end of the 30 m zone for error.
- Measure the go mark back from where the outgoing runner stands and place the check mark there, in metres or heel-to-toe steps.
- Test it at full speed. If the incoming runner has to ease off, move the mark further back. If they're shouting and still not catching, bring it closer. Change it half a step at a time.
Words used here
The check mark on the track behind the outgoing runner. When the incoming runner's foot hits it, the outgoing runner goes.
The 30 m stretch where the baton has to change hands. The outgoing runner starts inside it.
How far the outgoing runner has run when the baton changes hands. Later is faster, until it's too close to the end of the zone.
1Your team
Example times are loaded; replace them with your team's.
2The exchange
Most teams start at the very back of the zone (0 m) to get the longest run-up.
3Measuring
For converting the mark into heel-to-toe steps. Measure the spike, not the foot.
Fine-tune the model
The distance the arms cover. 1.6 m is what the Hong Kong team measured. Use less for a push or upsweep pass with less reach.
Runners have slowed slightly by the end of their leg. Drop this if your incoming runner fades badly.
How quickly the outgoing runner reaches top speed. Lower is quicker. 1.1 s is a typical value.
Your go marks
Distance back from where the outgoing runner stands to the check mark. When the incoming runner hits the mark, the outgoing runner goes.
See the exchange
Looking down on the lane, drawn to scale. Runners go left to right. Press play to watch the incoming runner hit the go mark and the pair meet at the pass.
Swipe sideways to see the whole lane.
Show the timing chart
Both runners' positions over time from the moment the incoming runner hits the go mark. The lines meet, less the arm gap, at the pass.
How this is worked out
Each runner's top speed is estimated from their 100 m time using the standard exponential acceleration model, where speed climbs towards a maximum with a time constant of about 1.1 s (Clark and Ryan 2022). The incoming runner holds a steady speed through the zone. The calculator finds how long the outgoing runner takes to reach the exchange point, how far the incoming runner travels in that time, and sets the go mark so the gap between them closes to arm's length exactly there.
With the speeds measured in the Hong Kong team, this method gives a go mark of about 9.4 m against the 9.47 m worked out in the study (Zhang and Chu 2000).
The model is a starting point. It can't see reaction time, nerves, a bend in the track or a runner who fades, which is why every mark needs testing at full speed.
The Rules
Since the 2018 rule change, the old 10 m acceleration zone and 20 m changeover zone are one 30 m takeover zone. The outgoing runner starts inside it, and the pass has to finish inside it.
In the 4×100 m and 4×200 m, the takeover zone is 30 m long. The outgoing runner must start from inside the zone.
Only the baton's position counts, not the runners' feet or bodies, and the whole baton is considered. The pass starts when the receiver touches it and ends when only the receiver holds it.
On legs run in lanes, the outgoing runner can place a check mark in their own lane. What counts as a legal mark varies (some school carnivals allow only Blu Tack), so check the meet's rules first.
The athlete who dropped it must pick it up, without getting in the way of anyone else. Runners stay in their lane after the pass until the track is clear.
Figure / Track map
Where the three exchanges happen
Swipe sideways to see the whole track.
Schematic, lane 1, stagger not shown. Each takeover zone starts 20 m before the line where the leg changes and ends 10 m after it. Legs 1 and 3 run the bends, so the first and third exchanges happen on or coming off a bend. The second exchange happens at the end of the back straight.
Passing Technique
Three passes dominate. Each trades reach against how much it disrupts the runners' sprinting action.
The receiver's hand stays low, palm down, and the baton is swept up into it. It keeps the arm action closest to normal sprinting, which is why Japan's teams built their relays on it. The catch is that the receiver ends up holding the middle of the baton, so it has to be shifted along before the next pass.
The receiver's arm goes back at about hip height with the palm facing back, and the baton is pushed forward into it. It disrupts sprinting less than the downsweep and is widely used by the USA, Jamaica and Great Britain.
The receiver's arm goes back high with the palm up, and the baton is brought down into it. It gives the most reach, but it pulls the receiver out of their running action and needs precise timing. It was the most common pass until the 2000s.
Coaching Notes
Practise exchanges at race speed. A go mark set during jogging drills is set for jogging. The incoming runner needs to be at full speed through the mark, and the outgoing runner needs to commit hard as soon as the incoming runner hits it.
Aim for the latest exchange you can make safely. The longer the outgoing runner accelerates before taking the baton, the faster the baton travels through the zone, but a pass that needs every metre will sometimes miss. A few metres of margin before the end of the zone is cheap insurance.
The incoming runner calls for the hand. The outgoing runner shouldn't look back after leaving. If the incoming runner is catching up early, the mark is too short. If they're shouting and the outgoing runner is pulling away, it's too long.
Leg order matters too. In a mathematical model of elite men's relays, the fastest overall times came with the fastest runner on the first leg and the two slowest on the last two legs (Ward-Smith and Radford 2002). Lane draw also affected times, which no coach can control. Treat this as one model's answer. Most coaches also weigh bend running, baton skills and who handles pressure on the anchor leg.
Full speed through the go mark, every time.
Move the mark half a step at a time.
Late and safe beats early and slow.
What this research can't tell you
The measured go marks come from one men's team at one local meet, and the model assumes the incoming runner holds a steady speed and the outgoing runner accelerates the same way every time. It doesn't account for reaction time, the bend on the first and third exchanges, or nerves on race day. Women's and junior teams will have different speeds and marks, which the calculator handles, but the 1.1 s acceleration constant is an average that some runners won't match.
This is general advice based on research and coaching practice, and it doesn't replace testing the exchanges with your own team. Warm up properly before any full-speed relay session: see the RAMP Warm-Up guide.
References
- Athletics Scotland (2016) Coaching the 4x100 Relay. Coaching conference handout, Glasgow.
- Clark, K.P. and Ryan, L.J. (2022) Hip torque is a mechanistic link between sprint acceleration and maximum velocity performance: a theoretical perspective. Frontiers in Sports and Active Living, 4, 945688.
- Ward-Smith, A.J. and Radford, P.F. (2002) A mathematical analysis of the 4 × 100 m relay. Journal of Sports Sciences, 20(5), pp.369–381.
- World Athletics (2023) Competition and Technical Rule Amendments, August 2023 (Rule 24: Relay Races).
- Zhang, B.-M. and Chu, D.P.K. (2000) The study of the optimal exchange technique in 4x100m relay. Proceedings of the 18th International Symposium on Biomechanics in Sports.
Figures and citations checked against the published sources, October 2026.