EXS420 Chapter 19 Quiz Study Guide

Functional speed utilizes the SSC

T

It is good to tell a jogger to keep their torso erect

T

Reaction time is relatively stable and correlate poorly with sprinting performance

T

Simple speed is relatively untrainable

T

When backpedaling one should originate the arm movement at the shoulders and shift the body weight primarily to the balls of the feet

T

Difference Between Elite Sprinters vs Novice Sprinters

- Elite sprinters spend relatively the same time on the ground as novice but are able to produce more force - Elite sprinters generally have longer stride lengths while also demonstrating a more frequent stride rate - Elite sprinters also have properly directed forces into the ground RFD and biomechanics are two of the primary limiting factors influencing sprint performance ELITE STRIDE LENGTH: 2.7m NOVICE STRIDE LENGTH: 2.56m ELITE STRIDE RATE: 4.63 steps / second NOVICE STRIDE RATE: 4.43 steps / second

Reactive Ability

- a characteristic of explosive strength exhibited in SSC actions that can be improved through reactive explosive training - EX: how fast does it take an athlete to get off of the block?

Spring Mass Model

- a mathematical model that depicts sprinting as a type of human locomotion in which the displacement of a body mass is the after effect from energy produced and is delivered through the collective coiling and extension of spring like actions within muscle architecture

Complex Training for SSC

- combination of plyometric and heavy resistance training - alternating SSC tasks with heavy resistance training exercises within the same session enhances their working effect POST ACTIVATION POTENTIATION:

Late Flight

- concentric hip extension: rotates thigh backward in preparation for foot contact - eccentric knee flexion: accelerates leg backward, limiting knee extension; stops before foot strike (aided by concentric knee flexion)

Mid-Flight

- concentric hip flexion: accelerates thigh forward - eccentric knee extension ----> eccentric knee flexion

Best Sprint Technique

- consists of an ideal ratio between downward push and horizontal push

Early Support

- continued concentric hip extension: minimizes braking effect of foot strike - brief concentric knee flexion followed by eccentric hip extension - eccentric plantar flexion: helps absorb shock and control forward rotation of tibia over ankle

KEY POINT: BRAKING MECHANICS

- decelerate with the FULL FOOT not heel toe or on toes

Momentum

- defined as the relationship between the mass of an object and the velocity of movement

Velocity

- describes both how fast an object is traveling and its direction - basically just speed with direction

Early Flight

- eccentric hip flexion: decelerates backward rotation of thigh - eccentric knee flexion: decelerates backward rotation of leg/foot

Late Support

- eccentric hip flexion: decelerates backward thigh rotation; rotates trunk in preparation for forward takeoff - concentric knee extension: propels center of gravity forward - concentric plantar flexion: aids in propulsion

Performing a Block Start

- front leg: 90° - rear leg: 130° - "on your mark" --> hips and head down - "get set" ---> hips up head down - front leg has the MOST impact on start forces - combination of vertical AND horizontal displacement + force

Magnitude

- measure of force

Training Goals to Maximize Speed

- minimize braking forces at ground contact by maximizing the backward velocity of the leg and foot at touchdown and by planting the foot directly beneath the center of gravity - developed systematically through consistent exposure to speed training as well as properly designed strength training programs - emphasize brief ground support times as a means of achieving rapid stride rate - emphasize functional training of the hamstring muscle group with respect to its biarticular structure and dual role during late recovery - eccentric knee flexor strength is the most important aspect limiting recovery of the leg as it swings forward - summary: front foot should land under body/directly under base of support, fast stride rate = short ground contact time, and functional training of hamstrings

Direction

- mixture of horizontal and vertical components

Sprinting

- rapid, unpaced, maximal effort of running for 15 seconds or less - an increase in stride length or in an increase in stride rate may increase sprint speed

Reaction Time

- relatively untrainable and correlates poorly with movement action time or performance in many explosive events - EX: the athlete's initial recognition and motion from the ready set go

Training Criteria to improve Stretch Shortening Cycle

- should involve skillful, multijoint movements that transmit forces through the kinetic chain and exploit elastic reflexive mechanisms - in order to manage fatigue and emphasize work quality and technique they should be structured around brief work bouts or clusters separated by frequent rest pauses - complex training which results in post activation potentiation - quality - high intensity frequent rest

Drills to Improve Stride Rate

- sprint assistance training - includes gravity assisted running (down grade sprinting on a shallow 3-7 degree slope - high speed towing - harness or stretch cord - or other means of achieving an overspeed effect **the objective is to provide assistance without significantly altering the athlete's movement mechanics, primarily as a means to improve stride rate

Drills to Improve Stride Length

- sprint resistance training - gravity resisted running (upgrades or upstairs sprinting) - harness - parachute - sled - weighted vest **objective is to provide resistance without arresting the athlete's movement mechanics, primarily as a means of improving explosive strength and stride length

Sprint speed is determined by an athlete's:

- stride length - stride rate

Stride Frequency

- tends to vary among individuals and generally seems to be more trainable than stride length due to limb length limitations

Speed - Endurance

- the ability to maintain maximal movement velocities or repeatedly achieve maximal acceleration and velocities - EX: how long an athlete can sustain maximal velocity in a 100m sprint?

Rate of Force Development

- the development of maximal force in minimal time, typically used as an index of explosive strength **within sports the ability to produce force rapidly is arguably more desirable train than maximal force production

Force

- the interaction of two physical objects - force is a vector quantity so it has both magnitude (size) and direction - traditionally described as push or pull exerted on one object by another, which prevents both objects from occupying the same space

Impulse

- the product of the generated force and the time required for its production, which is measured as the area under the force time curve

Acceleration

- the rate at which an objects velocity changes over time - acceleration of an object will continue to change as long as an external force continues to change velocity the movement of mass that changes an objects velocity

When functional movements are performed, force is typically applied very briefly that is often for ____ - ____ s whereas absolute maximum force development may require ____ - _____ s .

0.1 - 0.2 ; 0.6 - 0.8

Methods of Improving Speed

1. primary method: execution of sound movement technique in a specific task - initially athletes should perform tasks at submaximal speeds to establish proper mechanics 2. secondary methods: sprint resistance (underspeed) and sprint assistance (overspeed) 3. tertiary methods: mobility and strength

Depending on the movement, maximum power is usually produced at ___% to ___% of maximum force and velocity

30% to 50%

Which of the following is the BEST recommendation to give to a sprinter who runs with too much vertical displacement? a. use a longer push off with each stride b. raise the hips upward more than forward c. keep the torso more in an erect position d. focus the eyes on the ground slightly ahead of the feet

A. use a longer push off with each stride

When starting from the blocks in sprinting both of the following should be emphasized: swing the arms through a large range of motion and drive off the blocks with both legs

T

KEY POINT

The ability to achieve high movement velocity and accelerations involves high rate of force development as well as force application across a range of power outputs and muscle actions

A good way to improve stride frequency would be to do sprints pulling a weighted sled or perform lunges with heavy ( >85% 1RM) weights

F

Both jumping high and lifting a maximal weight require a large amount of impulse and power

F

Eccentric dorsiflexion contributes most to absorbing shock landing

F

Force application for developing maximal force is applied for about the same amount time as force is applied for activities like running and jumping

F

Functional speed depends on many factors including maximal strength and reaction time

F

Speed is defined as the "ability to maintain maximal movement velocities or repeatedly achieve maximal accelerations and velocities

F

There is a strong correlation between simple and functional speed

F

Force Application during functional movements (sprinting , jumping) vs movements that require maximal force (1RM bench press) - based on figure 19.1

Functional movements such as jumping and sprinting have limited time to produce force therefore explosive ballistic training is best for functional movements and achieving maximal force in a limited amount of time. Whereas, if an athlete has more time to produce force, heavy resistance trained athlete's will be able to achieve higher force production over time. However, most sport events take between 0.1-0.2 seconds to occur therefore an athlete will have minimal time to produce maximal force so ballistic training and explosive training receives priority for developing force production. summary: functional movements require faster RFD whereas maximal power movements require a slower RFD.

Reaction Time + Reactive Ability Relationship + Correlation w/ Explosive Events

Reaction time is relatively untrainable and correlates poorly with movement action time or performance in many explosive events whereas reactive ability is a characteristic of explosive strength exhibited in SSC actions that CAN be improved through reactive explosive training reactive ability includes the reaction and movement and is MOST important

True or False: Novice sprinters reach maximal stride length before elite sprinters.

True

True or False: Novice sprinters reach maximal stride rate before elite sprinters.

True

True or False: Novice sprinters reach maximal velocity before elite sprinters

True

In upright sprinting, an athlete's stride length is largely dependent on ____. a. the amount of vertical force produced during the stance phase b. the athlete's flexibility c. the athlete's stride rate d. the amount of horizontal force produced during the toe off of stance phase

a. he amount of vertical force produced during the stance phase

In a turn and run maneuver when transitioning from a backpedal into a forward sprint in the same direction, which of the following body parts initiates the movement? a. head b. shoulders c. hips d. feet

a. head

How many meters does it take for a novice sprinter to reach maximal velocity?

approximately 25m

How many meters does it take for an elite sprinter to reach maximal velocity?

approximately 45-55m approximately 4-5 seconds elite sprinters run 100m in about 10 seconds

Select the aspect of training that requires additional emphasis when the aim is to improve change of direction ability a. strength b. eccentric strength c. reactive strength d. rate of force development

b. eccentric strength

For a sprint athlete, which of the following exercises is best used to help develop the stretch-shortening cycle? a. squat b. overhead press c. snatch d. walking lunge

c snatch

Drills or tests that require the athlete to move rapidly in response to a stimulus such as a whistle, arrow, or opponent are best for measuring which of the following? a. change of direction b. maneuverability c. agility d. acceleration

c. agility

Which of the following is the most sport specific exercise for a sprinter? a. leg (knee) curl b. upright row c. dumbbell lunge d. ankle dorsiflexion

c. dumbell lunge

Elite sprinters produce _____ forces in a ______ ground contact time as compared to their novice counterparts a. larger ; longer b. similar ; shorter c. larger ; shorter d. smaller ; longer

c. larger ; shorter

As the rear thigh decelerates its backward rotation in the early flight phase of sprinting, which of the following muscles (of that same thigh) eccentrically controls backward momentum? a. biceps femoris b. gastrocnemius c. gluteus maximus d. rectus femoris

d. rectus femoris

What does the term impulse refer to? a. the relationship between power and velocity b. the relationship between acceleration and velocity c. the relationship between force and velocity d. the relationship between force and time

d. the relationship between force and time

An athlete has been performing overspeed sprinting on a high speed treadmill, sprinting at 20mph on a 20% grade. Which of the following will best minimize the risk of injury? a. use a spotter b. only sprint in 5 second increments c. hold onto the side rails d. use a harness

d. use a harness

Increases in running velocity at the beginning of a race versus the end

figure 19.5 demonstrates that in the beginning of a race, an athlete's stride length increases at the start of the rate then towards the end the stride frequency increases more while the length levels out

What would happen if the force velocity curve was moved up and to the left?

it would generate impulse and momentum during the limited time over which force is applied greater force + impulse in shorter amount of time

Power

rate of doing work measured as the product of force and velocity P = W / T

Speed

the skills and abilities needed to achieve high movement velocities - represented as a scalar quantity- only describes how fast an object is moving

Agility

the skills and abilities needed to change direction, velocity or mode in response to a stimulus - ex: moving to the side of the court to hit tennis ball

Change of Direction

the skills and abilities needed to explosively change movement direction, velocities, or modes - ex: re centering yourself on a tennis court after hitting the ball