Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Emergence of the advancing neuromechanical phase in a resistive force
  dominated medium   Undulatory locomotion, a gait in which thrust is produced in the opposite
direction of a traveling wave of body bending, is a common mode of propulsion
used by animals in fluids, on land, and even within sand. As such it has been
an excellent system for discovery of neuromechanical principles of movement. In
nearly all animals studied, the wave of muscle activation progresses faster
than the wave of body bending, leading to an advancing phase of activation
relative to the curvature towards the tail. This is referred to as
"neuromechanical phase lags" (NPL). Several multi-parameter neuromechanical
models have reproduced this phenomenon, but due to model complexity the origin
of the NPL has proved difficult to identify. Here we use perhaps the simplest
model of undulatory swimming to accurately predict the NPL during sand-swimming
by the sandfish lizard, with no fitting parameters. The sinusoidal wave used in
sandfish locomotion, the friction-dominated and non-inertial granular resistive
force environment, and the simplicity of the model allow detailed analysis, and
reveal the fundamental mechanism responsible for the phenomenon: the
combination of synchronized torques from distant points on the body and local
traveling torques. This general mechanism should help explain the NPL in
organisms in other environments; we therefore propose that sand-swimming could
be an excellent system to quantitatively generate and test other
neuromechanical models of movement. Such a system can also provide guidance for
the design and control of robotic undulatory locomotors in complex
environments.

32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph