The purpose of this study was to quantify movement coupling at the ankle du
ring the stance phase of running using bone-mounted markers. Intracortical
bone pins with reflective marker triads were inserted under standard local
anaesthesia into the calcaneus and the tibia of five healthy male subjects.
The three-dimensional rotations were determined using a joint coordinate s
ystem approach. Movement coupling was observed in all test subjects and occ
urred in phases with considerable individual differences. Between the shoe
and the calcaneus coupling increased after midstance which suggested that t
he test shoes provided more coupling for inversion than for eversion. Movem
ent coupling between calcaneus and tibia was higher in the first phase (fro
m heel strike to midstance) compared with the second phase (from midstance
to take-off). This finding is in contrast to previous in-vitro studies but
may be explained by the higher vertical loads of the present in-vivo study.
Thus, movement coupling measured at the bone level changed throughout the
stance phase of running and was found to be far more complex than a simple
mitered joint, or universal joint model.