Article discussing it here;
Over-Practicing Makes Perfect
Abstract here;
Reduction of Metabolic Cost during Motor Learning of Arm Reaching Dynamics
+ Author Affiliations
-
H.J.H., R.K., and A.A.A. designed research; H.J.H. performed research; H.J.H., R.K., and A.A.A. analyzed data; H.J.H., R.K., and A.A.A. wrote the paper.
Abstract
It is often assumed that the CNS
controls movements in a manner that minimizes energetic cost. While
empirical evidence for
actual metabolic minimization exists in
locomotion, actual metabolic cost has yet to be measured during motor
learning and/or
arm reaching. Here, we measured metabolic power
consumption using expired gas analysis, as humans learned novel arm
reaching
dynamics. We hypothesized that (1) metabolic
power would decrease with motor learning and (2) muscle activity and
coactivation
would parallel changes in metabolic power.
Seated subjects made horizontal planar reaching movements toward a
target using
a robotic arm. The novel dynamics involved
compensating for a viscous curl force field that perturbed reaching
movements.
Metabolic power was measured continuously
throughout the protocol. Subjects decreased movement error and learned
the novel
dynamics. By the end of learning, net metabolic
power decreased by ∼20% (∼0.1 W/kg) from initial learning. Muscle
activity
and coactivation also decreased with motor
learning. Interestingly, distinct and significant reductions in
metabolic power
occurred even after muscle activity and
coactivation had stabilized and movement changes were small. These
results provide
the first evidence of actual metabolic reduction
during motor learning and for a reaching task. Further, they suggest
that
muscle activity may not explain changes in
metabolic cost as completely as previously thought. Additional
mechanisms such
as more subtle features of arm muscle activity,
changes in activity of other muscles, and/or more efficient neural
processes
may also underlie the reduction in metabolic
cost during motor learning.
No comments:
Post a Comment