Fig 3. Pendulum setup.

Two planes were used to guide rollers attached to the lower limbs and pelvis. These guides constrained the specimen during the fall phase to a single degree of freedom (rotation at the foot point using a ball and socket joint and guidance planes). Cut guidance planes allowed for a free impact of the specimens, which slipped off the guidance planes right before impact and were only constrained by the ball and socket joint at the foot point. A pin-release constrained the motion of the contralateral leg during the fall phase but released it before impact. Rigid steel masses were added to the lower limb constructs to achieve target limb masses [45]. The knee impact point served to catch the knee at force plate level. Knee impact occurred well after greater trochanter impact.