Article

Sagittal bending moments acting on the lower leg during running may play a role
in tibial stress fracture development. The purpose of this study was to evaluate
these moments at nine equidistant points along the length of the lower leg (10%
point-90% point) during running. Kinematic and ground reaction force data were
collected for 20 male runners, who each performed 10 running trials. Inverse
dynamics and musculoskeletal modelling techniques were used to estimate sagittal
bending moments due to reaction forces and muscle contraction. The muscle moment
was typically positive during stance, except at the most proximal location (10%
point) on the lower leg. The reaction moment was predominantly negative
throughout stance and greater in magnitude than the muscle moment. Hence, the net
sagittal bending moment acting on the lower leg was principally negative
(indicating tensile loads on the posterior tibia). Peak moments typically
occurred around mid-stance, and were greater in magnitude at the distal, compared
with proximal, lower leg. For example, the peak reaction moment at the most
distal point was -9.61+ or - 2.07%Bw.Ht., and -2.73 + or - 1.18%Bw.Ht. at the
most proximal point. These data suggest that tensile loads on the posterior tibia
are likely to be higher toward the distal end of the bone. This finding may
explain the higher incidence of stress fracture in the distal aspect of the
tibia, observed by some authors. Stress fracture susceptibility will also be
influenced by bone strength and this should also be accounted for in future
studies.
CI - Copyright 2009 Elsevier B.V. All rights reserved.

Langue : ANGLAIS