Specificity of acceleration, maximum speed, and agility in
professional soccer players.
J Strength Cond Res. 2005 Feb;19(1):76-8.
Little T, Williams AG.
High-speed actions are known to impact soccer performance and can be
categorized into actions requiring maximal speed, acceleration, or
agility. Contradictory findings have been reported as to the extent
of the relationship between the different speed components. This
study comprised 106 professional soccer players who were assessed for
10-m sprint (acceleration), flying 20-m sprint (maximum speed), and
zigzag agility performance. Although performances in the three tests
were all significantly correlated, coefficients of
determination between the tests were just 39, 12, and 21% for
acceleration and maximum speed, acceleration and agility, and maximum
speed and agility, respectively. Based on the low coefficients of
determination, it was concluded that acceleration, maximum speed, and
agility are specific qualities and relatively unrelated to one
another. The findings suggest that specific testing and training
procedures for each speed component should be utilized when working
with elite players.
J Sports Med Phys Fitness. 2002 Sep;42(3):282-8. Related Articles, Links
Is muscle power related to running speed with changes of direction?
Young WB, James R, Montgomery I.
School of Human Movement and Sport Sciences, University of Ballarat, Ballarat, Victoria, Australia. w.young@ballarat.edu.au
BACKGROUND: The purpose of this study was to identify the relationships between leg muscle power and sprinting speed with changes of direction. METHODS: EXPERIMENTAL DESIGN: the study was designed to describe relationships between physical qualities and a component of sports performance. SETTING: testing was conducted in an indoor sports hall and a biomechanics laboratory. PARTICIPANTS: 15 male participants were required to be free of injury and have recent experience competing in sports involving sprints with changes of direction. MEASURES: subjects were timed in 8 m sprints in a straight line and with various changes of direction. They were also tested for bilateral and unilateral leg extensor muscle concentric power output by an isokinetic squat and reactive strength by a drop jump. RESULTS: The correlations between concentric power and straight sprinting speed were non-significant whereas the relationships between reactive strength and straight speed were statistically significant. Correlations between muscle power and speed while changing direction were generally low and non-significant for concentric leg power with some moderate and significant (p<0.05) coefficients found for reactive strength. The participants who turned faster to one side tended to have a reactive strength dominance in the leg responsible for the push-off action. CONCLUSIONS: The relationships between leg muscle power and change-of-direction speed were not consistent. Reactive strength as measured by the drop jump appears to have some importance for lateral change-of-direction speed, possibly because of similar push-off actions. It was concluded that reactive strength of the leg extensor muscles has some importance in change-of-direction performance but the other technical and perceptual factors than influence agility performance should also be considered.
Location: Solid Fitness Sciences, Kansas City, MO, 64112
Posts: 19
Interesting topic. Running is such a multi-dimensional form of movement, with the combination of concentric, eccentric, and isometric muscle actions. Hamstrings baby!...maybe the most important muscles of the legs. At a change in direction, there is a massive eccentric action on the hamstrings to offset the force applied against it...the equal and opposite reaction. At the point of change, it is isometric for a moment, like a pendulum swinging, then new direction. What also needs to be considered are the forces applied to the muscles that act synergistically, stabilizing the limb through the range of motion. At a change in direction, multiple vectors of force are applied at different angles that must be reacted to to allow proper change in direction. The stronger the reactive muscles are, the more force they can react to. The debate I have is the conclusion that power does not rate significantly with change in direction speed. Agility training for change in direction conditions the synergistic muscles to cancel those errant vectors of force more effectively. Plyometrics trains the muscles, especially the areas of insertion and origin, and more significantly, the tendons, to harnass and release more potential energy for bounding movements. This directly relates to power, as the speed through the range of motion is increased. At a running speed and then a change of direction, there is a drop in speed for a moment. Acceleration is needed to regain that speed. This requires power. Strength is key, too, as power is strength/unit time. Remember Barry Sanders? The guy is the most amazing runner I have ever seen. Squated something like 700 pounds. The cleans, agility, and plyometric training he did through his maturaion years, coupled with God's blessing, made him a machine. The acceleration, stop, change direction, and acceleration is unmatched by anyone in the game. His hamstrings hung like half moons when he would sit down. The dominance of his acceleration through a hole is testiment to how powerful he was. His change in direction prowess is testiment to his reactive strength, both eccentric and isometric actions, of his leg extensors and synergistic muscles. He just did it better, stronger, quicker, and with more authority than anyone else around him. Go outside one day and do some interval walk, jog, and sprint laps around happy hour. Then one day do some light weight, quicker rep squats, deadlifts, and then some cleans. Jump rope between sets. Do this around lunch. Then do the run routine at happy hour again. I'll bet you accelerate and sprint much faster. This might be the longest computer message I have ever typed. Enough. I like this forum. It is a learning platform for everyone involved to benefit from. Good night.
Acceleration is perhaps the most overemphasized aspect in athlete training today. From a performance standpoint, it is heavily outweight by ones' ability to decelerate. The athlete with the best brakes wins most of the time (not talking about track here folks...). To go a step further, the athlete who can decelerate best when he/she doesn't know WHEN they will have to decelerate will always be the better 'athlete' (CHAOS ).
__________________
Robert dos Remedios, MA, CSCS,
HCC (Hartman-Cosgrove Certified)
Director of Speed, Strength & Conditioning
College of the Canyons, CA http://www.canyons.edu/departments/pe/strength
"NO CHAMPION HAS EVER ACHIEVED HIS OR HER GOAL WITHOUT SHOWING MORE DEDICATION THAN THE NEXT PERSON; MAKING MORE SACRIFICES THAN THE NEXT PERSON; WORKING HARDER, TRAINING, AND CONDITIONING HIM / HERSELF MORE THAN THE NEXT PERSON; ENJOYING HIS / HER FINAL GOAL MORE THAN THE NEXT PERSON"
ability to accelerate, decelarate and change direction while maintaining dynamic balance of course there are various definition, but i think that basically sums it up
there is little to no correlation between agility , accelaration and absolute speed distinct motor qualities
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