The document discusses the complex motor control involved in the snatch lift from a neuroscience perspective. It describes how performing the snatch requires coordinated activation of muscles throughout the body within 2 seconds, posing an extreme challenge for the nervous system. It reviews the different areas of the brain and spinal cord that must work together, including the motor cortex, cerebellum, reflexes, and pattern generators. It discusses implications for coaching, including using demonstrations, video feedback, verbal cues, and different practice structures depending on the stage of learning.

1. Chris Hattersley – MSc, BSc, ASCC, CSCS, CES
The Snatch – Motor Control & Coaching

2. Overview
• Discuss the complexities of the snatch from a motor
control perspective.
• Review how learning occurs at each level of the motor
pathway and show how the different sub-systems
involved interact.
• Offer suggestions for how the snatch should be taught.
• Discuss different types of teaching as well as session
structure.

3. Technical Model
https://www.youtube.com/watch?v=uM2A0oMTajU

4. Snatch – Motor Control
• Closed skill, no reactive or perceptual
component.
• Co-ordinated activation of all muscles in the body
• High amounts of neural drive, rate coding, inter
and intra-muscular coordination.
• All carried out ~2 seconds!
• Extremely challenging for the nervous system to
coordinate this.
(Stone et al, 2006)

5. Key Principle of Neuro Science
• ‘Cortical area is
representative of the amount
of circuitry required to
perform a specific task’
• Areas involved with
movement are much larger
than the ones for maths and
language.
• Movement is the most
difficult task performed by
the body.
(Kandel et al, 2012)
1414 pages

6. The Brain and Movement
The brain has to co-ordinate nerve impulses through all the motor areas during the snatch.

7. Motor Homonculus
• This depicts the amount of circuitry
within the motor cortex designated
to each part of the body.
• Areas with smaller MU’s and more
refined movements require more
circuitry.
• The motor cortex provides a raw
motor signal instructing a specific
muscle to move.
• During the snatch the motor cortex
must synchronise nerve impulses
through each of these areas.
(Schott, 1993)

8. Sensory Homonculus
• Located at the front of the parietal
lobe.
• This area of the brain, processes
information on spatial awareness
and the planning of movements.
• Depicts the amount of sensory
circuitry designated for each body
part.
• Not as disproportionate as the
motor homonculus.
• (Schott, 1993)

9. Cerebellum
• Densest neural structure in the brain, 80% of the
brains neurons are located there! (Herculano-
Houzel, 2010).
• Integrates stored movement patterns with basal
ganglia inputs at the thalamus.
• Detects ‘motor error’ between intended and
actual movements.
• Involved in co-ordination and timing of fine
motor tasks.
• High potential for motor error during the snatch
as the inputs from higher and lower centres are
initially incorrect.
• Initial movements will be jerky and poorly timed
until the appropriate neural pathways are built
in the cerebellum.

10. Inputs to the Motor System
• Vestibular system, Visual System (Eyes),
Somatosensory System, Musculoskeletal
Systems, Nervous System.
• Anticipatory Postural Adjustments
(APAs) and Compensatory Postural
Adjustments (CPAs).
• Mechanoreceptors –pacinian corpuscle,
meissner corpuscles, merkel cells,
muscle spindles (nuclear bag, nuclear
chain), Golgi tendon organ.
• Gravireceptors - provide a neural
representation of the direction of
gravity with respect to an organism and
of motion of the organism with respect
to the gravity vector.

11. Spinal Cord Circuitry
• The spinal cord receives both descending and ascending inputs.
• This is happening at every level of the spinal cord, with every muscle in the body.
• Heavy snatch involves full activation of motor pool
(Pierrot-Deseilligny & Burke, 2012).

12. Reflexes / Pattern Generators
• The spinal cord co-ordinates how
nerve impulses are sent to the
muscles.
• Pattern generators integrate this
feedback and ensures rhythmical
movement of muscles and limbs.
• Ensures muscle are activated at the
right time in a smooth manner.
• Processed in the grey matter within
the spinal cord i.e. Motor neuron pool
• Pattern generators ensure both limbs
are activated at the appropriate time
during the snatch.
(Enoka, 2008; Zehr, 2005)

13. Integration of Subsystems
(Bosch, 2012)

14. So…..
• A novice cannot accurately calculate and
coordinate the muscular contractions needed
to execute the snatch efficiently.
• These circuits have a high amount of plasticity
and therefore movements can be learned and
refined with coaching.

15. Implications For Coaching

16. Demonstration
• One of the most fundamental types of coaching.
• Observational learning theory (Bandura, 1977).
• Visual perception perspective (Newell & Scully, 1985).
• Shows why we adopt or replicate the movements of others.
• Weaknesses, only discusses why demonstration might be beneficial
from a social and behavioural change perspective rather than biological.
• Possible neurological adaptations to this?

17. Demonstration
• It is widely accepted that a shared neural circuitry exists during
imagery and when performing a skill (Decety, 1996).
• A similar process happens when viewing the behaviour of others.
• This is termed the mirror neuron system (Rizzolati & Craighero, 2004).
• When watching a task the areas within the brain involved with that
task are activated (Rizzolati & Craighero, 2004).
• People with autism lack this system, reducing there capacity to learn
social and motor skills (Rizzollati & Fabbri-Destro, 2010).

18. Mirror Neuron System
Image A. Brain activity when viewing
static images of ;
• A face
• A hand
• A foot
Image B. Brain activity when viewing
videos of;
• Biting an apple and chewing
• Reaching and grasping for a ball with
the hand
• Kicking a football
• Parietal lobe activity in Image B. shows the participants are working out how to move
there body in the observed way.
Red = Face, Green = Arm, Blue = Legs. From Buccino et al, 2001.

19. Video Feedback
• Video is an objective method which can be used to monitor performance
and deliver feedback (Wilson, 2010).
• Variety of angles and speeds.
• Rucci & Tomporowski, 2010 - Compared, video + verbal feedback, verbal
feedback only and video only on 4x4 hang clean over 6 sessions.
• Video + verbal feedback and verbal feedback significantly improved.
• Knowledge of performance is more beneficial than knowledge of results.
• Need to develop there own unique movement pattern, rather than
imitate.

20. Verbal Feedback
• Instruction provides explicit cues before a task.
• Feedback is information provided after a task.
• Can vary how much feedback is provided and
when.
• More general for a novice, specific for advanced.
• (Hebert & Landin, 1994)

21. Organising Practice
• What structure to teach in i.e. reverse chain
• More than one skill at a time?
• Blocked, serial or random?
• Errorfull or errorless environment?
• Depends on the individual and the stage of learning.
• (Starkes & Erricson, 2003)

22. Stages of Learning
Stage of Learning Type of Training
Cognitive
Lots of instruction /
feedback
Partial lifts, rev chain
Lots of demo’s Emphasis on blocked
Practice in low reps Errorless
Associative
Less feedback, more
constraints
Partial & full lifts
Less demo’s Introduce, serial & random
Increase practice time Mix errorless & errorfull
Autonomous
Specialised feedback / video
analysis
Full lifts
Increase load Emphasis on random
The model is flexible and should include small amounts of each type of training
during each stage of learning, while also catering for individual learning styles.

23. Conclusions
• The snatch is a highly complex movement pattern
which requires a lot of time to perfect.
• High quality demonstrations and video feedback
are necessary but verbal feedback and cues from
an experienced coach may be more important.
• Different types of teaching and session structure
should be emphasized at different stages of
learning.

24. Any Questions

25. References
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• Bosch, F. 'Motor Learning In Athletics, The Great Unknown'. 2012. Presentation.
• Buccino, G., Binkofski, F., Fink, G., Fadiga, L., Fogassi, L., & Gallesse, V. (2001). Action observation activates premotor and parietal areas in a
somatotopic manner: An fMRI study. European Journal of Neuroscience, 13(2), 400-404.
• Decety, J. (1996). Do imagined and executed actions share the same neural substrate? Cognitive Brain Research, 3(1), 87-93.
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