Motor Skill Analysis Assignment

MOTOR SKILL ANALYSIS
HOPPING & THROWING
Travis Blandford
October 19, 2020
V2 Oct 3 2020
1

MEET THE PARTICIPANT
2
Name: Dwayne Blandford Age: 47
Sporting/Activity Background Dwayne has played sports recreationally throughout his entire life, most
recently playing roller hockey and slow pitch softball. He has never
received any formal coaching and is primarily self-taught.
Specific experience with your
skill
Dwayne has played multiple sports that involve overarm throwing, such as
football and baseball. He does not have as much specific experience
hopping on one foot.
Any impairments / limitations When asked, Dwayne said he has no impairments or limitations at this
time.
Additional notes Due to his job becoming much busier during the summer, Dwayne has not
been as physically active as he would like for a few months and feels he
has been somewhat deconditioned. Outdoor conditions were good, we
chose to film on a day with good weather and there was sufficient space
and traction in the back yard for both hopping and throwing activities.

KEY ELEMENTS OF HOPPING
(TEXTBOOK DETAILS)
3
Step 1 Hopping
(Haywood & Getchell, 2020)
Step 2 Hopping
Step 3 Hopping Step 4 Hopping

4
Action Step Basic Description Factors I will watch
for
Leg Action Step 1 Quickly lifts supporting leg to body, rather than pushing off the ground to
propel the body. Swing leg is inactive. Usually only one or two hops is
possible.
I will be watching for the
range of motion in the
swing leg, as well as the
level of extension of the
support leg.
Step 2 Forward lean allows the body to fall in front of the support leg, then catch
itself with the support leg. Repeated hops possible.
Step 4 Supporting leg extends to project body upwards. Swing leg assists support leg
by pumping up and down. Swing leg does not move behind the support leg.
Step 4 Swing leg leads, swinging to provide upwards and forwards momentum.
Large range of motion for swing leg, passing behind support leg. Supporting
leg extends fully on takeoff.
Arm Action Step 1 Arms are inactive, held usually out to the sides. It is also possible for the arms
to be held in front of or behind the body.
I will be watching for the
movement of the arms
relative to each other and
the swing leg, as well as if
and how they move
laterally.
Step 2 Arms swing upwards, then extend out in a wing-like movement to help with
balance.
Step 3 Arms pump up and down together in front of the trunk to assist. They may be
parallel or at different levels.
Step 4 The arm on the opposite side of the swing leg swings with it, the other arm
may be in variable positions.
Step 5 The arm opposite to the swing leg moves synchronized with the swing leg,
the other arm moving in the opposite direction.

VIDEOS - HOPPING
Video from side Video from front
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HOPPING– SCREEN SHOTS FRONT VIEW
6

HOPPING - SCREEN SHOT SIDE VIEW
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HOPPING SKILL ANALYSIS (Q1)
USING SCREEN SHOTS OF YOUR PARTICIPANT (THAT YOU WILL MARK WITH ARROWS/LINES),
REFERRING TO KEY ELEMENTS OF THE SKILL, AND PROVIDING DETAILED EXPLANATIONS,
DESCRIBE WHAT LEVEL WOULD YOU EVALUATE YOUR PARTICIPANT IN EACH ACTION (E.G. LEG
ACTION STEP 1, ARM ACTION STEP 2)
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In figure 1.1 we can see the swing leg leading, with an upwards and forwards motion
that peaks at it’s position in figure 1.2. The support leg starts in figure 1.1 somewhat
flexed from absorbing the landing of the previous hop, and by figure 1.2 it is fully
extended to project the body upwards. We can also see the right arm moving in the
same direction as the left (swing) leg in 1.1, with the left arm moving in opposition to
the right arm. However, this pattern does not clearly persist for subsequent hops.
Left limbs marked with blue and right with red.
Figure
1.1
Figure
1.2
Figure
1.3
In figure 1.3 we can see that the range of motion of the swing leg puts it behind the
support leg. We can also see that the right arm, on the opposite side of the swing leg
has also moved backwards, from in front of the trunk to more or less in line with the
trunk, but the movement is not very clear.
In the hops filmed from the side, I would say that because the swing leg had a large
range of motion and the support leg fully extended for takeoff, that the leg action is
at step 4. The arm action is less clear because it was not as consistent as the leg
action. I think it looked somewhere between step 4 and step 5 arm action, with the
(right) arm on the opposite side of the swing (left) leg swinging synchronized with
the swing leg, but with the (left) arm on the same side as the swing leg sometimes
moving in opposition to the right arm. I think step 4 arm action would be the most
accurate assessment though.

HOPPING SKILL ANALYSIS (Q1)
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For the hops filmed from the front, Dwayne opted to go for
maximum power/distance per hop. While the leg action
remained strong, the arm action very clearly regressed. In
figure 2.2 we can see the arms swinging up first, and in
figure 2.3 we can see them swinging out into a wing like
position to help with balance. This is a clear example of step
2 arm action.
Figure
2.1
Figure
2.2
Figure
2.3

HOPPING LAWS OF MOTION ANALYSIS (Q2) APPLY 3 SPECIFIC EXAMPLES
OF YOUR UNDERSTANDING OF NEWTON’S 3 LAWS OF MOTION, ROTATING
LIMBS AND PROJECTING OBJECTS, FORCE ABSORPTION, AND/OR
STABILITY AND BALANCE IN RELATION TO YOUR PARTICIPANT’S HOPPING.
(E.G. WHERE IS YOUR PARTICIPANT TAKING FULL ADVANTAGE OF THE
RULES OF MOTION AND STABILITY; WHERE IS THE LAW ACTING AGAINST
THE MOST PROFICIENT EXECUTION OF THE SKILL)
Newton’s Second Law - Force Absorption
 The principles of Newton’s second law of motion can be
observed at the moment Dwayne lands from the hop.
The knee goes from fully extended to flexed as it bends
to slow the descent. Since force is mass times
acceleration, reducing the acceleration will reduce the
force of the impact.
Newton’s First Law - Stability and Balance
 Newton’s first law states that an object at rest tends to
stay at rest until a force is applied to it. This is often
called inertia. You can increase your inertia by extending
your limbs, as can be seen when Dwayne extends his
arms to the side to increase his lateral rotational inertia.
This is a less developed arm action, and is likely in
response to the reduced stability from having a high 10

HOPPING LAWS OF MOTION ANALYSIS (Q2) APPLY 3 SPECIFIC EXAMPLES
OF YOUR UNDERSTANDING OF NEWTON’S 3 LAWS OF MOTION, ROTATING
LIMBS AND PROJECTING OBJECTS, FORCE ABSORPTION, AND/OR
STABILITY AND BALANCE IN RELATION TO YOUR PARTICIPANT’S HOPPING.
(E.G. WHERE IS YOUR PARTICIPANT TAKING FULL ADVANTAGE OF THE
RULES OF MOTION AND STABILITY; WHERE IS THE LAW ACTING AGAINST
THE MOST PROFICIENT EXECUTION OF THE SKILL)
Newton’s Third Law – Stability and Balance
 In this screenshot we see that as Dwayne brings his
swing leg up and begins to extend his support leg, he
moves his arms in opposition to his legs. This arm action
helps with balance by providing force in the opposite
direction of the force generated by the movement of the
legs. This is the most advanced step of arm action for
hopping and was only partially displayed in the video.
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IMPROVING HOPPING SKILLS (Q3) –
IDENTIFY 2 MAIN ERRORS THAT YOU
WOULD CORRECT (EXPLAIN WHY)
The leg action for the hopping was advanced and consistent, for both the more controlled hops filmed from the side
and for the power focused hops filmed from the front.
The arm action seemed to be the area that needed more work. The two main things I would work on would be
eliminating the lateral movement of the arms as much as possible, and focusing on improving the swinging of the
arm on the same side as the swing leg for the controlled hops. I think once good arm action was consistent with the
controlled hops, it would be easier to then begin increasing the distance of each hop without seeing the arm action
regress as much. This would help improve his stability while hopping.
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KEY ELEMENTS OF THROWING
(TEXTBOOK DETAILS)
13
(Haywood & Getchell, 2020)
Stage 1 Throw Stage 2 Throw
Stage 3 Throw (But with block trunk rotation) Advanced Throw Preparation

14
for
Trunk Action Step 1 No trunk rotation. There may be forward hinging at the hip. I will be watching to see
how much rotation of the
trunk occurs and how the
shoulders and hips rotate
relative to each other.
Step 2 Block rotation, shoulders and hips rotate together – first away to wind up,
and then in the direction of the throw.
Step 3 Differentiated rotation. Upper body twists away to wind up, then the hips
twist in the direction of the throw, the upper body following.
Backswing,
humerus, and
forearm
preparatory
backswing
Step 1 No backswing. Hand moves forwards to push the ball in the direction of the
throw.
I will be watching to see
where the ball is positioned
during the wind up (if it
goes behind the head) and
if it passes below the waist
during the wind up.
Step 2 Upper arm and forearm move upwards, bringing the wrist to the
shoulder/beside the head.
Step 3 Circular upwards backswing, the ball moving behind the head with a circular
motion with the arm extended at the elbow.
Step 4 Circular downwards backswing, with the ball moving down below the waist
before coming up behind the head.
Humerus action
during forward
swing
Step 1 The humerus moves forward to release the ball at an oblique angle. I will be watching to see
how the humerus is aligned
with the shoulder during
the throw, and whether it is
in front of the trunk when
the shoulders are
square/front facing.
Step 2 The humerus moves horizontally aligned with the shoulder, and by the time
the shoulders are square and front facing the humerus is in front of the
trunk.
Step 3 The humerus lags. When the shoulders are square and front facing, the
humerus is still in line with the trunk, elbow pointing to the side.

15
for
Forearm action
during forward
swing
Step 1 No forearm lag. The forearm moves forward constantly through the throw. I will be watching to see if
the forearm lags behind the
shoulders during the throw,
and at which point during
the throw it reaches the
furthest point of lag.
Step 2 The forearm seems to stay behind the body or move downwards, reaching
furthest back/lowest down before the shoulders are square/front facing.
Step 3 The forearm seems to stay behind the body or move downwards, reaching
furthest back/lowest down at the moment the shoulders are square/front
facing.
Foot action in
forceful throwing
and striking
Step 1 No step. I will be watching which
foot steps forward, as well
as how far the foot moves
during the step.
Step 2 Stepping with the same side foot as the throwing arm.
Step 3 Taking a short step with the opposite side foot of the throwing arm.
Step 4 Taking a long step with the opposite side foot of the throwing arm.

VIDEOS - THROWING
Video from side Video from front
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THROWING - SCREEN SHOTS FRONT VIEW
17

THROWING - SCREEN SHOT SIDE VIEW
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THROWING SKILL ANALYSIS (Q1)
19
Here we can see that there is trunk rotation. However, the hips and the
shoulders rotate more or less at the same time and rate. The hips do not
rotate before the shoulders, making this block rotation rather than
differential rotation. For this reason, Dwayne is at step 2 trunk action.
Figure
3.1
Figure
3.2
Figure
3.3
Figure
3.4

20
Figure
4.1
Figure
4.2
Figure
4.3
Here we can see the ball’s path during the
wind up for the throw. It travels down past
Dwayne’s waist in figure 4.2 and up behind
his head in figure 4.3. This is a circular
downward backswing, which puts Dwayne
at step 4 backswing action.

21
Figure
5.2
In figure 5.1 and figure 5.3 we can see that the humerus
is approximately in line with the horizontal plane of the
shoulders, at more or less a right angle with the trunk. In
figure 5.2 when the shoulders are square and front
facing, the humerus does not move outside of the
outline of the body. This looks to be step 3 humerus
action during forward swing in my opinion.
Figure
5.1
Figure
5.3

22
Figure
6.2
In figure 6.1 and 6.2 we can see that throughout the
forward motion of the throw, the forearm does not
noticeably lag. The forearm seems to remain more or less
vertical and ball seems to move fairly steadily forwards,
putting Dwayne at step 1 for the forearm action during
the forward swing.
Figure
6.1

23
Figure
7.3
In figure 7.1 through 7.3 we can see Dwayne take a long
step forwards with the foot on the opposite side of the
throwing arm. The distance of the step is more than half
of his height, putting him at step 3 foot action.
Figure
7.1
Figure
7.2

THROWING LAWS OF MOTION ANALYSIS (Q2) APPLY 3 SPECIFIC
EXAMPLES OF YOUR UNDERSTANDING OF NEWTON’S 3 LAWS OF MOTION,
ROTATING LIMBS AND PROJECTING OBJECTS, FORCE ABSORPTION,
AND/OR STABILITY AND BALANCE IN RELATION TO YOUR PARTICIPANT’S
HOPPING. (E.G. WHERE IS YOUR PARTICIPANT TAKING FULL ADVANTAGE
OF THE RULES OF MOTION AND STABILITY; WHERE IS THE LAW ACTING
AGAINST THE MOST PROFICIENT EXECUTION OF THE SKILL)
Newton’s First Law – Rotating Limbs and Projecting
Objects
 Because an object in motion tends to stay in motion at the same
velocity until acted on by a force, by releasing the ball with maximum
rotational velocity by fully extending his arm at the moment of
release and releasing the ball when at the point in the arc that it is
moving forward Dwayne ensures that the ball has the most forwards
velocity achievable.
24

Newton’s First and Second Laws – Projecting
Objects
 By increasing the distance over which the force is applied to
the ball, greater acceleration can be achieved. Dwayne can
be seen utilizing this principle when he takes a long
contralateral step when initiating the throw. If he also had
differential trunk rotation he would be effectively creating
more rotational distance for even greater acceleration, but
this was not observed in his throws.
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Newton’s First and Third Laws – Stability and Balance
 Because of the forwards momentum generated in the throw,
Dwayne’s body continues to tilt forwards in the follow through. By
tilting his trunk away from the throwing arm, he keeps as much of
this force in line with his base of support (his long stance as opposed
to a wide one) which helps with balance. In the follow through, his
throwing arm crosses his chest and the leg on the same side as the
throwing arm moves in the opposite direction, which also helps with
his balance by providing opposing forces.
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IMPROVING THROWING SKILLS (Q3) –
IDENTIFY 2 MAIN ERRORS THAT YOU
WOULD CORRECT (EXPLAIN WHY)
The first error I saw in the throw was the block rotation of the trunk. I would start here, focusing on rotating the
hips/pelvis before the shoulders to increase the velocity of the throw.
The second error I noticed was the lack of forearm lag in the throw, moving more or less consistently forward as the
trunk rotated forwards. Though it is not explicitly stated in the textbook why forearm lag is important, I would think it
has to do with extending the arm at the last possible moment before release for maximum throwing velocity.
27

EXTRA PAGE: FUNNY CLIPS
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Figuring out the camera - Not quite in the frame Dog toy
Dog toy can be seen here
from front view

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