Upper Body Motion to Go by Skating (with no poles) -- Roberts

But there is a refinement to the timing ideas given there -- because there is more freedom with the timing of arm-swing and other upper-body moves than with leg-recovery.

The additional timing points for forward-backward arm-swing are:

starting and accelerating backward motion should occur while the next foot is still in a low-transmission configuration for forward-backward propulsive work.

This point is not intuitive: The idea is not to "follow through" or "extend" any forward component of the arm-swing, but rather to cut it short. Stop the forward swing early, and start the backward recovery move immediately and early.

Double-push stroking: This timing means to start the backward move during the in-push. If wait to make the move until the main leg-push outward, you lose half the propulsive benefit from this forward-backward move.

Normal-push stroking with angle-switch (see more): Start the backward motion during the early part of the next foot's push, while the foot is still aimed close to the direction of overall forward motion.

Normal-push stroking with hop (see more): Start the backward motion while both feet are still up in the air, before the next foot lands on the ground.

slowing and stopping of backward motion should occur after the next foot gets into a high-transmission configuration for forward-backward propulsive work.

Double-push stroking: This timing means during the main-push outward.

maximum backward velocity should optimally be timed to occur during the "aim-switch" phase A of double-push stroking (between the in-push and the main-push)

Normal-push stroking with angle-switch (see more): Maximum velocity of backward motion should optimally be timed to occur during aim-angle-switch from skate aimed close to forward to skate aimed more out toward the side.

Normal-push stroking with hop (see more): Maximum velocity of backward motion should optimally be timed to occur just as the next foot lands on the ground.

The timing points which are similar to forward-backward leg-recovery are:

starting and accelerating forward motion should occur while the next foot is in a high-transmission configuration for forward-backward propulsive work -- optimally later during this phase.

This timing means to start the forward motion during the main-push outward. "Later" means like Phase 3.

slowing and stopping of forward motion should occur after the next foot gets into a low-transmission configuration for forward-backward propulsive work.

Double-push stroking: This timing means during the in-push.

Normal-push stroking with angle-switch (see more): Stop the forward motion during the early part of the next foot's push, while the foot is still aimed close to the direction of overall forward motion.

Normal-push stroking with hop (see more): Stop the forward motion while both feet are still up in the air, before the next foot lands on the ground.

maximum forward velocity should optimally be timed to occur just as the previous foot comes up off the ground.

This means at the end of phase 3 and the beginning of phase R.

[ more to be added ]

Arm swing motion

Side-swing of arms

Timing

for normal-push this move occurs in Phase 1 and again in Phase 3.
Similar reactive-force acceleration / deceleration timing considerations as for the abdomen-torso side-swing moves.

[ more to be added ]

special recovery move in V1 skate with poling

A special version of arm side-swing is the forward-recovery path for the recovery-side arm in V1 skate -- performed on skis with poling.

The idea of this V1 skate technique is to make one double-pole push down and backward starting as the foot on one side is set down and starting to push, then recover the arms forward while the other leg is pushing.

After the finish of its pole-push downward and backward, the hand and arm make two moves: (1) first outward toward the side, then (2) inward and forward and across toward the other side.

Timing: For maximum contribution to propulsive work: The outward move of the arm should be synchronized with the torso side-swing move toward the recovery-side -- which might require a small delay after the finish of the pole-push: hold back, then go quick. Timing of the inward move is not so critical, because the positive and negative propulsive work from its acceleration and deceleration phases is self-cancelling (provide that the start of its next pole-push is at or before the set-down of the poling-side leg).

Up-Down component of arm swing

[ more to be added ]

Forward-Backward swing of arms

?? forward-backward component to arm-swing -- useful mostly only for double-push.

Not useful for simple "straight-stroke-path" normal-push -- but could be useful for some variations of normal-push, such as with "angle-switch" or with a "hop". See discussion above under forward-backward recovering-leg moves.

[ more to be added ]

Torso + Shoulder moves

Side-swing of torso+shoulder

Muscle moves:

abdomen-torso side-swing move for reactive side-force

chest-shoulder side-swing move for reactive side force

timing coordination

occurs in Phase 1 and again in Phase 3.
In phase 1 it "catches" the kinetic energy from the side-weight-shift of the previous leg-push and by decelerating the mass of the upper body, generates beneficial reactive side-force to the current push.
In Phase 3, it starts the side-weight-shift of the upper body toward the other side, and this acceleration generates beneficial reactive-side-force to the current push. The stronger and quicker the acceleration of the upper body, the more work added to propulsion.

positional configuration

Note that this rotation or swing is in the opposite direction of the rotation of the pelvis and hips in the forward-hip-rotation move.

[ more to be added ]

Up-Down moves of torso+shoulder

Muscle moves

back-extension

the move of stopping the falling and then raising the mass of upper body applies beneficial reactive down-force thru the leg,

timing

for normal-push: mainly in Phase 3.

[ more to be added ]

Forward-Backward moves of torso+shoulder

Muscle moves:

?? forward-backward move of torso + shoulders -- useful mostly only for double-push.

[ more to be added ]

what's here

see more pages on upper body

see other topics

Overview

body-part groups

arm-swing moves

torso-shoulder moves

kinds of Leg-push stroking

Three dimensions of upper body moves

Side-swing moves of Upper Body

Up-Down moves of Upper Body

Forward-Backward moves of Upper Body

Timing relative to Leg moves

Arm swing motion

Side-swing of arms

special recovery move in V1 skate with poling

Up-Down component of arm swing

Forward-Backward swing of arms

Torso + Shoulder moves

Side-swing of torso+shoulder

Up-Down moves of torso+shoulder

Forward-Backward moves of torso+shoulder

more . . .

see also

more on upper body

other topics