Comparison of Joint Kinematics in Transition Running and Isolated Running in Elite Triathletes in Overground Conditions.

Triathletes often experience incoordination at the start of a transition run (TR); this is possibly reflected by altered joint kinematics. In this study, the first 20 steps of a run after a warm-up run (WR) and TR (following a 90 min cycling session) of 16 elite, male, long-distance triathletes (31.3 ± 5.4 years old) were compared. Measurements were executed on the competition course of the Ironman Frankfurt in Germany. Pacing and slipstream were provided by a cyclist in front of the runner. Kinematic data of the trunk and leg joints, step length, and step rate were obtained using the MVN Link inertial motion capture system by Xsens. Statistical parametric mapping was used to compare the active leg (AL) and passive leg (PL) phases of the WR and TR. In the TR, more spinal extension (~0.5-1°; p = 0.001) and rotation (~0.2-0.5°; p = 0.001-0.004), increases in hip flexion (~3°; ~65% AL-~55% PL; p = 0.001-0.004), internal hip rotation (~2.5°; AL + ~0-30% PL; p = 0.001-0.024), more knee adduction (~1°; ~80-95% AL; p = 0.001), and complex altered knee flexion patterns (~2-4°; AL + PL; p = 0.001-0.01) occurred. Complex kinematic differences between a WR and a TR were detected. This contributes to a better understanding of the incoordination in transition running.