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Speed-Endurance, Repeated Sprint Ability

Berry College - Dept. of Kinesiology
by

David Elmer

on 16 April 2014

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Transcript of Speed-Endurance, Repeated Sprint Ability

Repeated-Sprint Ability
Essential component of most team and individual sports
Short sprints (< 10 sec) with short recoveries (< 60 sec)
However, research on this topic is sparse
2 components:
Single sprint performance
Ability to recover between sprints
Good RSA
= average sprint performance
Poor performance
- initially very fast, but significant effect of fatigue
- consistent speed with little fatigue, but speed is slow
e.g. marathon runner running repeated sprints
Limiting factors
Energy supply
H accumulation
+
Muscle activation
Think back to energy systems topic...
Sprints mainly stress:
ATP-PC system
Glycolysis
30 sec half-time of recovery
activated immediately
not fully activated until ~30 sec
Must use carbohydrates to function
lactate production
Can you train to increase the rate of PCr recovery?
YES.
ADP + PCr
ATP + Cr
Aerobic metabolism is primarily responsible for PCr resynthesis
law of mass action...
Endurance training and High-intensity Interval Training (HIIT) can significantly improve PCr resynthesis rate
however, some discrepancies between studies examining different HIIT strategies
could be related to when the PCr measurement was taken (after 3 min)
Accomplished through increase in aerobic fitness
repeated sprint training can also improve aerobic fitness
Bishop & Edge (2006)
Girls with similar single sprint performance times, but different levels of aerobic fitness, were matched
girls with greater aerobic fitness showed less of a decrease in performance during a repeated sprint test
Five 6-sec max sprints completed every 30 seconds
Glycolysis is stimulated by ATP-PC activity
highly active during a single sprint, but activity is reduced with repeated sprints
not clear whether increasing rate of glycolysis will improve repeated sprint ability
Sort of a catch-22: correlation between glycolytic energy production and decrease in repeated sprint performance,
BUT
greater rate of glycolysis would result in a greater initial sprint performance
relationship between initial sprint performance, final sprint performance, and total sprint performance
BAD
GOOD
increased glycolytic rate = increased anaerobic capacity
can be accomplished through extremely high-intensity endurance training
Greatest increases in anaerobic capacity from exercise that results in big increase in blood lactate concentration
but not through moderate intensity endurance training
20-120 sec intervals at 100-200% of Vmax
60 min at 70% of VO max
> 10 mmol/L
best way to do this is 20-30 sec all-out activity separated by ~10 min of recovery
but repeated sprints also stress:
Aerobic Energy System
not fully activated during a single sprint
could be not just fully activated, but at maximum capacity during repeated sprints...
Potential factors to improve RSA:
increased resynthesis of ATP and PCr
faster oxygen uptake
faster re-oxygenation of muscles
higher lactate threshold
higher VO max
moderately correlated with repeated sprint performance
greater fatigue resistance, especially towards the end of a repeated sprint test or activity
may be reaching VO max
Velocity at VO max
How to improve aerobic fitness (VO max):
intensity at least 60% of VO max for a sufficient amount of time (volume)
High-intensity interval training (various strategies)
Probably more effective for concurrently improving repeated sprint ability, and more time-efficient
ADP + PCr
ATP + Cr
1
2
% VO max
La-
untrained
Trained
10
20
30
40
50
60
70
80
90
100
2
2
2
2
Speed Endurance
Ability to maintain top speed for > 6 sec
Requires sufficient metabolic power
ATP-PC system
Glycolysis
Aerobic Metabolism

Training Methods:
Supramaximal, maximal, and submaximal training
greater intensity, but shorter duration than competition
equal intensity and duration to competition
lesser intensity, but greater duration than competition
Traditional endurance training
70-95% intensity of competition, longer duration
structured changes in intensity, duration, etc.
High-intensity interval training (HIIT)
high intensity work intervals interspersed with limited rest
Repetition training
high intensity work intervals interspersed with near complete recovery
Glycolytic stress
Aerobic stress
Type of training...
should depend on the demands of the task/sport you are training for
duration of sustained activity
breaks in play (planned & unplanned)
intensity of position, role on a team
increases in H , or decreases in pH could potentially impair RSA
Work (J)
Sprint #
1
2
3
4
Repetition training (2-3 min rest)
HIIT (30 sec rest)
How do you measure decline over a series of sprints?
Fatigue Index =
100 x
(Best - Worst)
Best
Percent decline =
(
1
-
(when bigger numbers = better performance)
(S + S + S + ... S )
S x # of sprints
)
x 100
1
2
3
final
best
Percent decline =
(when smaller numbers = better performance)
(
(S + S + S + ... S )
S x # of sprints
- 1
)
1
2
3
final
best
x 100
2
+
greater initial sprint performance results in greater repeat performance declines
increases in H inhibit glycolytic energy production
+
*affects rate-limiting enzyme
Lactate transporters, along with other buffering systems, help regulate pH in the muscle
co-transport and anti-port mechanisms
Buffer systems can be improved with training stimuli at or near 100% VO max, as long as the rest periods are kept short
2
*not necessarily top sprint speed
Ability to maintain a given level of voluntary activation of muscles may be critical for repeated sprint performance
recruitment
firing rate
training to improve muscle activation:
eccentric strength (?)
plyometric training (?)
Training Strategies
Repeated sprint training
"Tentative conclusions":
Very few studies examining adaptations to repeated sprint training.
even fewer comparing repeated sprint training to other types of training
vs.
High-intensity interval training
VO max
Buffering capacity
Best sprint
Mean sprint
Reduced performance decline
* So... probably best to include both types of training
Sprint training
Little to no research on traditional sprint training and repeated-sprint ability
Increasing single-sprint performance is related to increasing mean sprint time in repeated sprint performances
Small sided games
only 2 studies have examined small sided game effects on repeated sprint ability
showed nonsignificant improvement compared to other types of training
potential for both aerobic stress and improved neuromuscular function
Resistance Training
Increases in:
mean work
first sprint performance
performance decline
Especially in muscular endurance strength training
2
2
* if rest periods are kept short...
central fatigue
David J. Elmer
2
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