Author(s): MATSUBAYASHI, T., TAKAHASHI, K., YAMANAKA, R., ONUMA, H., KAGEYUKI, T., GOTO, H., KOIZUMI, J., MAKINO, M., GARRANDES, F., ADAMI, P.E., BERMON, S., Institution: JAPAN INSTITUTE OF SPORTS SCIENCES, Country: JAPAN, Abstract-ID: 1280

INTRODUCTION:
In the 4×100 m relay, outcome depends not only on sprint capacity but also on baton-exchange efficacy. Yet quantitative evidence on how exchange kinematics affect performance in elite teams remains limited. We aimed to identify the main determinants of exchange efficacy, and to quantify exchange-related time loss by comparing observed data with best-possible performance estimated via simulation.
METHODS:
Eight teams per men’s and women’s final were recorded by seven high-speed cameras (239.76 fps). Multi-view 3-D reconstruction yielded runners’ velocity profiles, and exchange onset and completion were identified from video. We measured takeover-zone time, bottom velocity of baton (minimum of incoming and outgoing runner velocities), exchange position, free distance (distance between runners at exchange completion), and exchange duration. Best-possible baton velocity was then simulated by modeling minimal incoming deceleration (linear) and near-maximal outgoing acceleration (exponential) and by placing the exchange at the velocity crossover point. Achievement ratios for takeover-zone time and bottom velocity of baton were computed by comparing observed with simulated values.
RESULTS:
Simulated finish times were 0.22 to 0.54 s faster than observed in men and 0.12 to 0.80 s faster in women. Exchange-related time loss varied widely from one team to another and was not necessarily smaller in higher-ranked teams. Takeover-zone time achievement ratio ranged from 90.5 to 99.4% in men and 89.9 to 100.0% in women, differing by up to 10 percentage points. Bottom velocity of baton correlated strongly with takeover-zone time in both sexes and in both observed and simulated datasets (r = −0.711 to −0.962). Their achievement ratios were also correlated (r = 0.828 to 0.935). Observed exchange position was consistently earlier than simulated optimal and was associated with both achievement ratios (r = 0.532 to 0.754). Free distance also correlated with both achievement ratios (r = 0.444 to 0.666), whereas exchange duration showed no association with either.
CONCLUSION:
Exchange-related time loss is substantial and varies widely across teams, confirming room for improvement even for the highest-ranked teams. Efficacious exchanges are governed primarily by preserving baton velocity. When the incoming runner covers most of the takeover zone at high velocity and the outgoing runner accelerates maximally, a short takeover-zone time is achieved with a later exchange position. Conversely, when the incoming runner approaches too early, spacing collapses and free distance shortens; the incoming runner decelerates, the outgoing runner has not fully accelerated, and baton velocity drops—lengthening takeover-zone time. Exchange position and free distance likely reflect these velocity conditions rather than acting as independent causal factors. Teams should prioritize protecting baton velocity by minimizing velocity loss, then fine-tune exchange position while balancing gains against disqualification risk.