Advanced strength and conditioning physiology Flashcards
What’s a motor unit composed of?
Muscle fibers and motornueron
Innervation ratio = motor unit per muscle fibres
1: 10 -eye
1: 500 - tibialis anterior
1: 1000 - biceps brachii
lower in the eye as need finer control
Motor unit types?
Slow twitch oxidative
Fast twitch oxidative
Fast twitch glycolytic
What is the motor pool?
Group of motor neurons in the spinal cord, innovating a single muscle
Large range of number motor neurones dependant on muscle
It’s heterogeneous
What order is motor recruitment?
Size principle
Smallest then largest later
Asynchronous activation
What is rate coding?
AKA frequency coding
Range of 3 to 120 impulses per second
Constant tension/slow =15-50
Fast = 80-12-
Notes for the exam:
2 x 500 word essay
Each essay may include one small table that is not included in the word count but only counts for section C
Each essay is to be the same content and structure
Overall mark is worth 30% of your grade
One to the medical team, one to the athlete
A) Why is rate of force development important for athletes?
B) What are the key physiological aspects to consider when looking at rate of force development
C)How can you assess and improve RFD
Section A - One small paragraph
Section B - Two paragraphs, so two aspects
Section C - One smallish paragraph and a table
Referencing doesn’t count to word count (in brackets)
Harvard
Turn in 10th December
End of week 4 will be ready to start assessment
Scientific third person past tense
Lay summary more informal
Explosive strength?
The rate of rise in contractile force at the onset of contraction
Rate of force development?
The maximal rate of rise in muscle force
Boxing = contractions times of?
50-250ms
But sometimes it might be impossible to get reach the required force in that time so can be 300ms plus
Higher rate of force development do what?
Run faster and jump higher
Is rate of force development more sensitive to changes in neuromuscular function?
yes
So rate of force development as a measure of muscle damage
Rate of force development as an adjunctive outcome measure for return to sport decisions after anterior cruciate ligament reconstruction
Myofibre damage in human skeletal muscle: effects of electrical stimulation versus voluntary contraction
How to measure RFD?
You measure either voluntary contractions or evoked reactions?
Voluntary contractions:
Big hump
RFD = change in torque (force) / change in time
Evoked:
Purely down to a stimulation causing the muscle to contract
What is compliance?
Rope for dog lead = lots of compliance
Metal pole for dog lead = little compliance
On graph lots of up and downs = lots of compliance
Biological compliance?
Soft tissues compression
What’s smoothing?
When you smooth out the data curve on the graph, remove the ups and Downs
Mad as doesn’t accurately show where the contraction starts
Force relies on?
Amount of motor recruitment
What time the motor units discharge at = rate coding
Motor units are recruited in size of?
Size of soma
Smallest to biggest
Small ones small muscles low velocities
Big ones big muscle high velocities
Motor unit pool is pretty much all recruited before the peak so it’s the rate coding aka discharge rate (Hz) which is responsible for the max value
Notes for RFD assessment?
Important as can show when athletes are ready to return to play
Helps acceleration due to rapid increase in force development
General everyday abilities
Key physiological functions: (pick one from each)
Neural: MU recruitment threshold MU discharge rate/ rate coding Muscle activation/neural drive MU synchronisation
Muscle: Muscle fibre type Muscle size Pennation angle - not understood Fascicle length - not understood Muscle tendon stiffness
How can you asses RFD:
Force time curve
Reduced Ca2+ in calcium kinetics results in?
Slower force production
Reduced troponin C leads to a reduced force production
Also by delivering a triplet stimulation results in increased calcium then increased force but quickly returns to normal levels, hence it might not be useful when things starts to fatigue
Ortenblad et al 2000 showed that 5 week Wingate cycle training resulted in?
Increased Ca2+ release
Enhanced Power output rate and average power output rate
Enhanced sarcoplasmic reticulum content:
Increased SERCA1, SERCA2, RyR
No change in SR Ca2+- ATPase capacity or uptake rate
No change in MHC distribution
RFD could be affected by?
Increase in calcium sensitivity
Chronic changes vs acute changes?
Chronic: Calcium release Calcium reuptake Enhanced SR content Increased SR Ca2+ ATPase capacity
Increase in calcium sensitivity
Can put this in my assessment
Self case study?
Conduct a thorough assessment of your ability to technically execute each exercise
Identify effective methods that can be implemented to improve the technical skill execution of each exercise
Implement suggested methods
Once methods for improvement have been implemented, perform a before and after analysis appraising any improvement or lack of improvement
Suggest further methods for improvement (eg. if given a longer time period to make improvements/how would you make further progress
Squat variation: Bodyweight Goblet Front Back Overhead
Other type: Deadlift Lunge Push up Bent over row Romanian deadlift
Steps for second piece of CW?
Choose exercise
Record yourself doing the exercise
Asses your ability to do the exercise, highlighting areas of improvement
Identify methods to improve exercises
Implement methods to improve exercise
Record yourself doing the exercise (after)
Compare before and after footage of you doing the exercise. Appraise improvement and/or non improvement
Identify future methods for improvement
Squat university
`film front and side
10 minute video, microsoft stream?
don’t have to have references
Look at oliver whitton practical videos to get a good idea how to do the video
show exercises and gradual improvement
What is velocity based training?
a method that uses velocity to inform or enhance training
Lets you accurately predict 1RM with sub maximal loads
Variables of interest?
Mean concentric velocity
Peak concentric velocity
Minimal velocity threshold?
is the mean concentric velocity produced on the last successful repetition of a set to failure performed with maximal lifting effort
Linear periodisation?
Reductions in training volume accompanied by increases in training intensity
Also a periodic sequence focusing on distinct physical qualities
Non-linear periodisation?
Varying volume and intensity using different RM’s or near RM’s
Reverse linear periodisation?
Reductions in training intensity accompanied by increases in training volume as the programme advances
Block periodisation?
Focused mesocycles arranged in sequential blocks (e.g. accumulation, transmutation, realisation)
Conjugate periodisation ?
Training several physical qualities during that compliment each other (e.g. strength and power)
Concurrent periodisation?
Training competing qualities within a mesocyclone (e.g. strength and endurance)
Early view on more mechanical stress causing fitness adaptations?
Improved performance until reaching points such as burnout
