Week 4 - Speed Training Flashcards
According to Gaitanos et al., (1993) what is the percentage contribution of glycolysis to total ATP resynthesis during a 6-second all-out effort?
44.1%
There’s evidence to suggest that speed training leads to an ⬆️ in activity of glycolytic enzymes.
List 3 of these
PK (Pyruvate kinase)
Enolase
TPI (Triose P Isomerase)
Function of PK
Phosphoenolpyruvate + ADP + H+ –> pyruvate + ATP
in glycolysis.
Function of enolase
2-phosphoglycerate –> phosphoenolpyruvate + H20
Function of TPI (Triosephosphate isomerase)
Dihydroxyacetone P – triose P isomerase –> glyceraldehyde 3-P
According to Gaitanos et al., (1993) what is the percentage contribution of the PCr system to total ATP resynthesis during a 6-second all-out effort?
57%
PCr stores deplete during an all out sprint.
– Replenished during recovery period.
Which energy system provides ATP for this recovery?
Myokinase pathway
What is the name of the enzyme involved in the myokinase pathway
Myokinase / ADK - Adyenlate kinase
Equation for myokinase reaction
ATP + AMP <=> 2ADP
Dawson et al., (1998) + Thorstensson et al., (1975) found a significant increase in the activity of the myokinase / ADK. What percentage increase did they report?
19%
During an all-out sprint we activate our Fast Fatigable (FF) motor units.
Do they have a low, moderate or high innervation ratio?
High innervation ratio
What does the innervation ratio refer to?
Defines the no. of muscle fibres innervated by a single motor neurone.
What motor neuron does the action potential travel down after leaving the spinal cord?
Somatic motor neurons (alpha motor neuron)
Define speed
Ability to move the body as quickly as possible over a set distance. Associate it w/ max-intensity exercise lasting 2-10s.
How to calculate speed
Distance / time
How to assess speed in the field
Stopwatch
Timing gates (more accurate)
In what way can speed be improved
By enhancing the tension + length-impulse response involved in the rapid exchange between eccentric + concentric muscle action during sprint activity.
Why is use of plyometric or explosive strength training an adv. to speed development?
Due to improvements seen in the stretch-shortening cycle (SSC).
Main adaptations over prolonged speed training
⬇️ muscle stiffness
Enhanced NM activation
At which point can olympic-caliber athletes accelerate through in a 100m sprint
70m mark
Define 1 stride
2 steps/foot strikes
Define stride rate
No. of steps taken w/ each leg during distance of run.
What stride rate do elite sprinters have
Approx 5/sec
What happens as stride rate increases
Time spend on ground ⬇️ = flight phase ⬆️.
Constant stride length + ⬆️ stride rate = ?
⬆️ speed
Constant stride rate + ⬆️ stride length = ?
⬆️ speed
Which is more important when determining runners Max velocity
Stride rate
In regards to running, what does improved power allow
Athlete can ⬆️ acceleration ability by ⬇️ ground contact time of each stride + ⬆️ impulse production on takeoff.
MUSCLE FIBRE-TYPE COMPOSITION
What is speed influenced by?
Structural architecture of skeletal tissue:
- Muscle thickness
- Length of fascicle
- Pennation angle of fascicles
What does a large pennation angle allow?
Ability to generate greater force - associated w/ greater speed of contraction.
Typical speed training programme
3-4 sessions/week
4-20 reps per session
Less than 10secs of exercise per rep
90-100% max. Speed
Work:Rest > 1:6
Benefits to resisted speed training
Enhanced neural function
⬆️ reflex potentiation
⬆️ type II muscle fibre cross-sectional area
Cautions to resisted speed training
Greater resistance may damage running technique, negating any pot. benefit from resisted running.
Recommendations for resisted running drills
18-37m
3-4 sets of 4-8 reps
Recovery - 90-120s
Assisted speed or overspeed training
Uses downhill sprint or implements to help athletes run faster than they normally do.
— Can ⬆️ stride freq. + length more than possible w/ traditional sprint exercises.
-ive outcome to assisted speed or overspeed training
Risk of changing running technique = slower sprint times.
— Been recommended that athletes don’t exceed 100% of their max. Running speed.
Metabolic adaptations to speed training
⬆️ activity of creatine kinase, myokinase + glycolytic enzymes.
⬆️ proportion of type II muscle fibres.
⬆️ muscle fibre cross-sectional area.
What pathways majorly contribute to ATP resynthesis during all out sprints
PCr + glycolytic
Influence of speed training on motor unit recruitment / neural adaptations
⬆️ motor neurone firing freq.
⬆️ conduction velocity
⬆️ proportion + activation of type 2 motor units/fibres
Enhancement of SR Ca2+ release
What causes Ca2+ release from SR?
What happens after?
AP travelling down T-tubule
Ca2+ Binds to troponin = Allowing binding of actin + myosin == Contraction.
Pathway of AP from start to muscle fibres
Down spinal cord
Branches into somatic motor neurones (alpha motor neurone)
Transmits AP towards skeletal muscle.
Each alpha motor neurone attaches to multiple muscle fibres.
What does an AP travelling down a motor neurone cause?
Contraction in all fibres innervated by that neurone.
What happens with regards to a single AP?
Contraction of the fibres - a twitch.
What is req. for sustained + forceful muscle contraction in association with AP?
Successive motor neurone APs
What is the force + speed of contraction affected by?
Freq. of AP from motor neurones
No. of motor neurones transmitting AP.
What are the 3 motor unit types
Fast Fatigable (FF)
Fast fatigue-resistant (FR)
Slow (S)
What is the histochemical profile of fibres of the 3 motor unit types
FF – FAST GLYCOLYTIC (FG)
FR – FAST OXIDATIVE GLYCOLYTIC (FOG)
S – SLOW OXIDATIVE (SO)
Order motor unit size from FF to S motor unit types
FF -Large
FR - Medium
S - Small
Order INNERVATION RATIO from FF to S motor unit types
FF - High innervation ratio
SO - Low innervation ratio
Advice for ind. aiming to ⬆️ speed
Speed training
Resistance training (Traditional, High velocity + power)
Plyometrics
Movement Specific Training (Resisted Sprints).
How many sprints are performed in a team sports game?
Typically 25-40
How long are the sprints performed in a team sports game?
2-4s
How far are the sprints performed in a team sports game?
15-25m
Heavy resistance vs. high velocity/power training
Heavy resistance training ⬆️ maximal muscle force prod.
Explosive power training ⬆️ maximal muscle force prod + rate of force development
== Both should be incorporated into a sprinters programme.
When is muscle excitability reduced?
When K+ builds up outside the muscle cell.
How does speed training prevent a reduction in muscle excitability?
⬆️ no. of Na+-K+ ATPase pumps
Why is more Ca2+ released from the SR after speed training?
⬆️ in SERCA and RyR
What is a high leg muscle volume typically associated with?
Acceleration
What is the initial improvement in strength following the onset of resistance training due to?
Neural adaptations
To what type of speed training is there currently limited evidence to support the use of it?
Assisted sprints.
