Our results support the hypothesis that OpenSim can effectively
model cycling and predict external knee joint (i.e. net muscle)
moments. Although peak values for knee flexion moments were lower
than published values [6], other pilot experiment results revealed that
higher peaks can be obtained by increasing machine resistance levels.
The OpenSim predicted pelvic loads from ID reasonably matched the
HBSEs. Interestingly, the ID results predicted the expected result that
pelvic loads were dominated by the superior-inferior component; in
that direction, ID results differed from HBSEs by 9.2%. Handlebar
forces in the medial-lateral direction were not reported [6]; thus,
appropriate HBSEs for that direction could not be computed.
In this study, kinetics were defined as body forces rather than
more accurately defined as point forces, thus future work will include
restructuring the method for kinetic data collection and subsequent
import into OpenSim. Further, future work will include implementing
a marker set more conducive to reducing soft tissue artifact.
OpenSim’s residual reduction algorithm (RRA) will be used in an
effort to reduce modeling errors. Following RRA, further use of
OpenSim tools [3] will be used to predict both muscle and joint
contact loads, addressing our long-term goal of developing an
improved understanding of knee joint contact loads during cycling for
patients at high risk for knee OA