Gait Posture. 2015 Mar;41(3):745-9. doi: 10.1016/j.gaitpost.2014.12.010. Epub 2014 Dec 27.
Jeopardizing Christmas: Why spoiled kids and a tight schedule could make Santa Claus fall?
Donath L1, Roth R2, Lichtenstein E2, Elliot C2, Zahner L2, Faude O2.

Abstract
Santa Claus’ spatio-temporal gait characteristics, ground reaction forces during treadmill walking as well as postural sway during loaded, unloaded and cognitive interference tasks were examined in order to estimate his fall risk. Seventeen healthy males, disguised as researchers and students (age: 30±10 years; height: 179±6 years; weight: 76±7kg; BMI: 24±2kg/m(2); physical activity: 12±4h/week) and who still believe in Santa Claus randomly underwent balance and gait analyses with and without cognitive interference. The conditions were to be dressed as “Santa Claus” (wearing costume consisting of a beard, cap, robe, heavy sack with a load of 20kg) or dressed in “normal clothing” (no costume). Spatiotemporal gait parameters (walking velocity, gait variability and stride time, length and width), ground reaction forces (GRF) (left- and right-sided heel strike and push off) and postural sway (30s tandem stance on a force plate) were measured. “Santa-effects” (0.001<p<0.05; 0.21<ηp(2)<0.72) and “Dual-task effects” (0.001<p<0.003; 0.46<ηp(2)<0.86) were found for postural sway (increased sway), GRF (decreased forces for dual tasking, increased forces for the Santa condition) and the majority of spatio-temporal gait parameters. Significant “Santa”×”Dual-Task” interaction effects were not observed (0.001<p<0.05; 0.21<ηp(2)<0.72). Relevant leg effects of GRF during walking were not found. Santa Claus faces a tremendously increased risk of falling when carrying his Christmas sack with 20kg of presents. Cognitive loads also impair his neuromuscular performance. It is recommended that Santa trains his strength and balance before Christmas and also to avoid filling his sack with more than 20kg of presents. Also, cognitive training may help to improve his dual task performance.