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Exercise Physiology Lecture 2 SP20 Neuromuscular Patterning

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Exercise Physiology
Lecture 2 - Neuromuscular Movement Patterning and Conditioning
Homework
Read Chapter 1 and 14 in your text.
Performance Objectives
1. Describe the way in which a movement pattern is developed and adapts to repetition.
2. Describe movement pattern development training methods.
3. Describe factors which cause a movement pattern to breakdown and compensatory
movements to develop.
4. Describe the assessment and functional training concepts used to maintain normal
movement patterns and rehabilitate abnormal ones.
5. Describe various methods for improving functional movement patterns.
6. Describe the development of improved strength/peak power in a movement pattern.
7. Describe strength and power assessment and training methods.
8. Describe the concept of post-activation potentiation.
1. The Development of Movement Patterns
-
Movement patterns originate both naturally (hard wired responses) and through
repetition (hard wiring created by doing the movement over and over again).
This is referred to as motor learning - teaching the neuromuscular system to
automate a given movement.
-
Natural movement patterns emerge as the nervous and muscular systems develop
over time if they are not inhibited in some way. Examples include the movement
patterns for walking and running.
-
These movements patterns are regulated by the nervous system autonomically
from the cerebellum (see below), meaning we do so without need for conscious
level control from the cerebral cortex (outer upper portion below). Essentially the
cerebellum sends and receives neuronal signals to and from the muscles allowing
the activity to occur.
-
Learned movements patterns (mostly everything else in sport and fitness) are
created by repetition. If a movement is repeated consistently (without much
variation) using conscious control, the nervous system creates a network of new
synaptic connections that ultimately allows the movement to become autonomic
overtime.
-
Changes in the body structure resulting from things like muscle atrophy, nerve
damage, habitual positioning, injury, sedentary lifestyle) can result in
modifications to a basic motor patterns resulting forcing compensatory
movements patterns to develop, i.e. think of limping when you have hurt a foot
for instance.
-
Pre-existing movement patterns make the development of new motor patterns
more difficult - “can an old dog learn new tricks”?
-
The development of movement patterns is relatively fixed because a change in the
nervous systems structure and organization has occurred - “once you learn to ride
a bicycle you can always do so”.
Questions to consider:
Which movement patterns are natural and which must be learned?
What factors might interfere with the normal development of walking and running
movement patterns?
How does applying a stressor to a movement pattern effect its development?
What are the implications of a compensatory movement pattern?
2. Successful Adaptation to Repetition
-
Repetition works the quickest to automate a new movement pattern if a previous
one does not really exist (as in beginners) and little variation occurs in practice
“perfect practice makes perfect.
-
Both fatigue and loss of concentration often result in a change in a movement
pattern, particularly when a pre-existing or more elemental one exists - i.e. the
swimmer who becomes tried swimming the crawl stroke and begins to dog
paddle.
- once a movement pattern can be well regulated consciously, the application of
increased resistance resulting in increased neuronal signaling, appears to improve
nervous system adaptation allowing it to become autonomic. This is easiest to
regulate consciously in short efforts.
-
Several examples of this concept in practice include using paddles in swimming,
swimming short fast efforts while focusing on the stroke cues and using resistance
training movements that replicate various parts of the swimming movement
specifically.
-
Organizing practice or training in a new movement in a way that minimizes the
confounding nature of fatigue is thought to enhance the motor learning processes.
Questions to consider:
How can you determine the best movement pattern to teach?
How can you manipulate a practice or training environment to maximize motor learning?
How can you create conscious regulation?
How can you create conditions that help a movement pattern to emerge spontaneously,
reducing the need for conscious regulation?
How can you create feedback as to the success of developing new movement patterns?
3. The Breakdown of Movement Patterns and the Development of Compensatory
Movements.
-
Injury is one of the most common ways a movement pattern is altered. Humans
will instinctively avoid creating pain by unloading (or limiting use) of an injured
joint or muscles. This forces other joints and muscles to alter in the way they
work temporarily. If the compensatory pattern persists over time, motor learning
occurs and this becomes the dominant way of moving.
-
Sedentary behavior in general, and sitting in particular, creates muscle
imbalances, changes in posture and losses in joint mobility and balance which
inevitably lead to the emergence of compensatory patterns in exercise related
movements.
The Alexander technique is a method used to correct posture during movement. It
is based on the concept that a overly flexed cervical portion of the vertebral
column (as in forward head posture) inhibits movement of the entire vertebral
column and function of the spine, which intron inhibits normal movement
capability. http://www.alexandertechnique.com/
-
The over application of a stressor may also lead temporarily to the use of a
compensatory movement increasing the possibility of acute injury. Thinking of
the method used when excessive weight is lifted in a standing curl for instance.
-
Our existing body asymmetries may drive us toward dysfunction over time. In
particular humans have more tissue and weight on the right half of their body
cavity (larger 3 lobe lung and heavy liver) which creates the tendency to weight
the right leg more with a resulting twisting of the pelvis to the right and so on.
Correction of this tendency is described by practitioners of postural restoration.
https://www.posturalrestoration.com/
-
Compensatory patterns inevitably result in limitations to the ability to adapt to
increased stress in the movement, reduce effectiveness (work capacity) in the
movement and increases the possibility of new injuries in the overloaded joints
and muscles.
Questions to consider:
How can compensatory movement be evaluated?
How can compensatory movement be changed?
How can the development of compensatory movement patterns be avoided?
4. The Use of Functional Training to Enhance Movement Development and
Maintenance
-
Functional training refers to the emerging concept of training using movement
patterns with broad based application and which encourage full mobility and
balance.
-
While limited science exists currently, evidence supporting the utility of this
approach in preventing and rehabilitating injury as well as improving movement
performance is emerging rapidly.
-
In particular, recent research has focused on the Functional Movement Screen in
terms of it’s efficacy: 1) as an assessment tool, 2) in predicting injuries, 3) in
responding to interventions, and 4) as a determinant of performance.
Some Recent References
Article Describing the FMS in two parts.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2953313/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2953359/
FMS in Prediction of Injuries
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3924605/
Review Article
http://journals.lww.com/nscajscr/Abstract/2014/12000/Efficacy_of_the_Functional_Movement_Screen___A.3
4.aspx
-
Typical examples of functional training movements (which are ultimately nearly
unlimited) include the full squat with arms overhead, lunges in all directions with
arms overhead and torso rotations, chopping and throwing movements, the
traditional Olympic lifts, etc.
-
Functional training may both acutely stimulate and chronically maintain mobility
and balance.
-
Functional training movements can be targeted to specific imbalances and
compensatory movement patterns, used generally for prevention and used acutely
for preparation (warm-up).
-
Movement ability can be assessed suing a simple to administer series of
functional training movements. These are scored relative to the occurrence of
compensatory movement patterns during attempts. This process allows for the
classification of ability, the diagnoses of specific compensatory movements and
limitations and the prescription of training to correct the movement pattern.
Questions to consider:
How can functional training assessment and training be used in the context of an exercise
program, athletic training program and rehabilitation program?
Should physical training proceed if movement patterns are flawed?
5. Methods to Improve Deficient Functional Movement
A. Corrective Exercise
The use of corrective exercises designed to enhance mobility, core control and the
integration of these factors in balance and coordination as assessed by the FMS has been
shown to improve FMS scores in several populations.
In mixed martial artists:
https://journals.lww.com/nscajscr/FullText/2015/01000/The_Effect_of_an_Intervention_Program_on.28.aspx
In Fireman:
https://content.iospress.com/articles/work/wor2493
In football players:
https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0838.2009.01038.x
Improved FMS scores following intervention (as above) has been associated with
improved running performance.
http://www.conscientiabeam.com/pdf-files/phy/90/JSR-2019-6(1)-1-8.pdf
B. Reflexive Performance Reset
The use of reflexology activation points to acutely change the activation state of muscles
so as to allow for normal movement patterns (without compensation) to occur.
This approach has as yet not been examined scientifically although it is rapidly gaining
interest resulting from positive anecdotal reports and an active group of strength and
conditioning professionals promoting its use.
The method consists of creating a stimulus on reflexology points by rubbing them briefly
but vigorously to provoke an increased neuromuscular signaling to the muscle associated
with that reflexology point.
C. Use of diaphragmatic breathing.
In breathing disorders (hyperventilation – mouth breathing) whereby the diaphragm is not
activated appropriately motor control is sacrificed as the diaphragm contributes
substantially to both posture and motor control in complex total body movements such as
running.
The presence of breathing disabilities has been shown to be related to FMS scores.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3924606/
Diaphragmatic breathing occurs naturally when breathing nasally.
Questions to consider:
1. Can the RPR temporarily acutely allow for improved movement patterns and
increased performance.
2. Could regular use of the RPR protect against injury?
3. Could improved breathing result in improved functional movement ?
4. Could improved breathing protect against injury?
5. What should come first – movement correction or movement loading?
6. The Development of Improved Strength and Power in a Movement Pattern
-
When exposed to a new stimulus in terms of force the neuromuscular response
adapts in two key ways:
A. An improved ability to recruit muscle motor units (higher percentage)
B. Remodeled motor units which have more myofibrils (see below),
hence produce greater force
-
Improved motor unit recruitment happens rapidly.
-
Principle of orderly recruitment
Muscle size – smaller muscle recruited at low force, larger (often external)
muscle recruited as force increases.
Fiber type – smaller slow twitch fibers recruited first at lower forces, fast
twitch fibers gradually added as force increases.
-
Increased fiber size (hypertrophy) happens more slowly.
-
Complete restructuring of damaged muscle fibers may take days to week
depending on the severity of damage.
-
The most important stimulus to consider is the intensity and volume of the work
placed on the movement, not necessarily the perception of effort.
-
optimizing muscle restructuring will require adequate protein intake, optimal
hormonal response, adequate rest and time.
-
Muscles act to create movements so specificity dictates we should “train
movements, not muscles”
-
muscles act in tandem (pairs) against each other so to maintain normal joints
positions (posture) and movement patterns, movements should be trained in pairs
(i.e. bench press and row) to maintain muscle balance.
-
most repetitive activities will overdevelop on side of the pairing (the propulsive
muscles movement)
Chronic Adaptations to Resistance Training in Muscle Fibers
Increased Fiber Size
Decreased capillary density
Decreased mitochondrial density
Decreased twitch contraction time
Glycolytic enzymes Increased
ATP, PC and Glycogen Store Increased
VO2 max unaffected except through CWT
Ligament, tendon strength Increased
Bone mineral density increased, no change in cross section
Questions to consider:
How long does this process take in a given individual?
What factors can be manipulated to improve adaptation?
How does genetics influence the process?
Are there gender based differences?
Is improved strength in a movement related to improved endurance in the movement?
How can a training program be designed to create balance?
7. Strength and Power Assessment and Training Methods
A. Definitions
Strength - maximum force produced in a single repetition
Absolute Strength - maximal force
Relative Strength - maximal force relative to some other variable like body weight or lean
weight.
Power - work (force x distance) accomplished per unit time - sometimes called work rate
B. Strength/Power Measurement/Training Tools
Strength
1. Dynamometry - spring loaded devices, no movement so work not measured directly.
2. Machine Movements - little need for stabilization, fixed motion, sometimes partially
accommodating resistance, work can at least be estimated if the resistance is not
accommodating (irregular cam used).
3. Free Weight Movements - more natural, benefit from momentum, work can be
measured and timed.
4. Isokinetics - fully accommodating resistance, but rate controlled, work not
measureable.
5. Resistance Bands - versatile but very limited resistance, work not measureable.
6. Callisthenic Movements (sit-ups, etc.) - Not really strength assessments, work can be
estimated in some cases where body weight is elevated.
7. Functional Resistances - the movement of large, sometimes unusual objects - work
generally not measureable.
Power
- Power can be assessed in any method where work is measured, and time to
complete the movement tracked.
Training Principles for Strength and Muscular Hypertrophy
A. Strength and Peak Power
 greater resistance producing greater contractile force than normally used
produces increases in muscular strength

lesser resistance producing less contractile force but more sustained contraction
increases muscular endurance

to continue to produce overload, progressive increases in resistance must occur

Muscular strength develops more quickly than the supportive tissues (ligaments
and tendons); also caution must be used in progression.

Balance between antagonistic muscle groups is also important to prevent injury
and maintain symmetry

All movements are dependent to some degree on “core” body strength

Strength is specific to speed and motor pattern - “train movements not muscles”

May be greater muscle activation with alternate concentric work and slower
speeds

Periodization employs planned cycling of intensities to maximize the results
process

Strength development is counterbalanced by endurance training in the same
muscles - strength tends to improve endurance performance, however endurance
training also inhibits strength
Use of Periodization in Strength/Power Training
-
refers to a planned variation which occurs cyclically based on the following
building blocks (training cycles)
Microcycle - short term (1 week typically)
Mesocycles - combination of microcycles by emphasis (4 weeks typically)
Macrocycle - Long term combination of mesocycles (16 weeks for instance)
Periodization Types
1. Linear - organized by distinctly different emphasis across mesocycles
Example.
Phase1
General Muscle Endurance
3 x 15 at 50% of the 1 RM
Phase 2
Strength
3 x 5 at 85% RM of the 1 RM
Phase 3
Power
4 x 4 at 50% of the 1 RM at maximum speed*
*Power output optimizes between 50-70% of the 1 RM.
2. Undulating - variations within a microcycle which is repeated throughout
Example
Microcycle
Monday
Wednesday
Friday
General Muscle Endurance
Strength
Power
Developing Muscular Hypertrophy (body building) Principles





increased muscular force activation increases hypertrophy
volume of work done may affect this response as well
total body muscularity increases through activation of all muscles
body builders typically employee high volume and high resistance with multiple
exercises and a large number of sets
Periodization might still apply
Delayed Onset Muscle Soreness
A. Eccentric Contraction Effect
 associated with increased intra-muscular damage and, DOMS in numerous
studies
B. Model
1. Unaccustomed exercise with eccentric component
2. Damaged sarcolemma (fiber membrane) releasing cytosolic enzymes and
myoglobin to the blood
3. Damaged myofibrils and non-contractile structures
4. CA+ concentrates in the cell apparently causing more damage and reduced
contractile force
3. DOMS at about 24-48 hours due to inflammation
4. Muscle structure redevelop, inflammation reduces, pain disappears
5. Muscle resistant to similar stress for up to six weeks
C. Prevention and Relief
 avoid eccentric work or progress it slowly
 initiate training programs with light exercise make small planned progressions
in training
 use light recover exercise, stretching, massage to facilitate healing process
Widely Used Resistance Training Methods
A. Conventional Weight Training
 Conventional exercises used to promote balanced general body strength and
muscular development
B. Plyometric Training
 Specific use of conditions (boxes, jumping, etc) that encourage a rapid prestretch of muscles and explosive response to maximize the stretch reflex and
peak power.
C. Sport Specific Resistance Training

Use of sport specific movements with resistance to transfer improved muscle
force capability to sport performance through the mechanism of improved
efficiency.
 Particularly applicable to sports where movements are repeated frequently
D. Body Building

Use of balanced total body training to create total muscle balance, symmetry,
definition and hypertrophy, generally for competition
E. Power Lifting
 Specific lifts (bench press, squat and dead lift) used in competition to determine
the strongest competitor
 Not particularly transferable to other sporting activities due to their isolated
nature
F. Olympic Lifting
 Specific total body lifts (snatch and clean and jerk) used in Olympic
competition to define the strongest competitor
 The large degree of agility required to perform the lifts and their total body
nature make them highly transferable to other sporting activities, particularly
those without highly repetitive movement patterns such as most team sports.
”Train to Failure” versus “Train at Target Set” Approaches
-
The train to failure concept refers to performing repetitions until a repetition
cannot be completed due to neuromuscular fatigue.
-
The targeted set approach targets a specific weight (% of 1 RM) and a number of
repetitions that can be completed without reaching failure.
-
Research examining this suggests that both are effective or shorter time frames,
while target set approaches may work better over longer time frames.
-
Advantages of a targeted set approach are increased reduced perception of effort,
less likelihood of overtraining, the ability to perform more total work at a given
intensity with less fatigue resulting in improved adaptability
-
Disadvantages of a targeted approach are that a measureable system must be sued
and it is more time consuming.
Examples:
Failure Approach: 3 x reps to failure at 85% of 1 RM - generally be about 6-8 reps.
Targeted Approach: 4-6 x 5 reps at 85% of 1 RM.
Prescribing Individual Training Sessions
Assess the 1 repetition maximum (1 RM) using a 1 RM test or a submaximal estimation
of 1 RM.
Base Training on %s of the 1 RM at a targeted level that avoids failure sets by 1-2 reps or
more.
Increase resistance used as effort is reduced (adaptation occurs) and/or as a new 1 RM is
established.
Consider that early strength gains may occur very rapidly due to improved neuromuscular
activation, conservative progression is still best to avoid injury as soft tissue (tendon,
ligament) adaptation will be much slower.
Questions to consider:
How often should given training sessions occur?
How can training principles be applied?
How can adaptation be evaluated?
8. Post-activation Potentiation (PAP)
Some evidence and considerable anecdotal observation exists to support the idea that
movement patterns can be facilitated acutely by using non- fatiguing and relatively high
power/force applications movements in warm-up.
Examples include:
1) completing a pyramid warm-up (progessively heavier sets) in weight training with an
at or near to 1 RM repetition prior to the main training sets,
2) completing high velocity/power activities such as bounding or sprinting (sometime
called strides in running) prior to the main set in an endurance activity.
In running:
https://www.ncbi.nlm.nih.gov/pubmed/17530940
Review addressing the research overall:
https://journals.lww.com/acsmessr/Fulltext/2002/07000/Postactivation_Potentiation__Role_in_Human.8.aspx
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