ELITE JUNIOR HANDBALL PLAYERSlibproject.hkbu.edu.hk/trsimage/hp/06000851.pdf · handball are highly dependent on the player’s physical capacity. In between the exchange of offense

RELATIONSHIP BETWEEN STRENGTH OF KNEE

EXTENSOR AND FLEXOR AND YOYO

INTERMITTENT ENDURANCE TEST IN

ELITE JUNIOR HANDBALL PLAYERS

BY

LAM CHI HO

06000851

AN HONOURS PROJECT SUBMITTED IN PARTIAL FULFILMENT OF

THE REQUIREMENTS FOR THE DEGREE OF

BACHELOR OF ARTS

IN

PHYSICAL EDUCATION AND RECREATION MANAGEMENT (HONOURS)

HONG KONG BAPTIST UNIVERSITY

APRIL 2008

HONK KONG BAPTIST UNIVERSITY

25 th April, 2008

We hereby recommend that the Honors Project by Mr. Lam Chi

Ho entitled “Relationship between strength of knee extensor

and flexor and YoYo Intermittent Endurance Test in elite

junior handball players” be accepted in partial fulfillment

of the requirements for the Bachelor of Arts Honors Degree

in Physical Education and Recreation Management.

________________________ _______________________

Dr. Tong Kwok Keung Prof. Chow Bik Chu

Chief Adviser Second Reader

ACKNOWLEDGEMENTS

I would like to express my gratefulness to my chief advisor,

Dr. Tong Kwok Keung, for his kind and professional suggestions

throughout the whole project period. I would also like to give

thanks to Miss Lu Kui from Dr. Stephen Hui Centre for Physical

Recreational and Wellness, for guiding me in the use of the

laboratory equipments. Lastly, thank you for the Hong Kong

Junior Team Handball Team players for their participation.

________________________________

Lam Chi Ho Department of Physical Education Hong Kong Baptist University

Date: 25 th April, 2008

ABSTRACT

YoYo Intermittent Endurance Test was very popular in

assessing the performance and aerobic ability of athletes.

On the other hand, isokinetic dynamometry was more

accuracy to assess the ability of muscle strength of

athletes today due to technical improvement. However, the

contribution of the two different abilities of muscle

endurance and muscle strength were seldom reported. This

study was to examine the relationship between strength of

knee extensor and flexor and YoYo Intermittent Endurance

Test. Seven male Hong Kong Junior Team Handball Team

players were participated in this study with age, 15.43

± 1.40 years; weight, 68.36 ± 9.86 kg; height, 180.14 ± 7.71

cm. The knee extensor and flexor was assessed by isokinetic

dynamometry (Humac Norm). For the YoYo Intermittent

Endurance Test, the measurement of the total distance

covered was obtained in this study. It was found that there

was no significant correlation between the knee extensor

and flexor muscle strength and the performance of YoYo

Intermittent Endurance Test [(r = 0.491, p > 0.05) and

(r = 0.401, p > 0.05)]. The contribution of knee extensor

and flexor muscle strength was 24.1% and 16.1% to the

performance of YoYo Intermittent Endurance Test (r 2 =

0.241) and (r 2 = 0.161) respectively. The findings suggest

that there was weak relation between knee extensor and

flexor muscle strength and the performance of YoYo

Intermittent Endurance Test.

TABLE OF CONTENTS

CHAPTER Page

1. INTRODUCTION. . . . . . . . . . . . . . . . . . . 1

Statement of the Problem. . . . . . . . . . . 3

Hypothesis. . . . . . . . . . . . . . . . . . 3

Significance of the Study. . . . . . . . . . . 4

2. REVIEW OF LITERATURE. . . . . . . . . . . . . . . 5

The Importance of Muscular Strength. . . . . . 5

The Importance of Leg Strength

on Running Sports. . . . . . . . . . . . . 6

Factors that Affecting Muscle

Strength and Endurance. . . . . . . . . . . 7

Testing Methods of Strength. . . . . . . . . . 14

Isokinetic Systems. . . . . . . . . . . . . . . 15

YoYo Intermittent Endurance Test. . . . . . . 16

Definition of Terms. . . . . . . . . . . . . . 18

Summary. . . . . . . . . . . . . . . . . . . . 23

3. METHOD. . . . . . . . . . . . . . . . . . . . . . .24

Subjects. . . . . . . . . . . . . . . . . . . . 24

Procedures. . . . . . . . . . . . . . . . . . . 25

Test Protocol. . . . . . . . . . . . . . . . . .26

Statistical Analysis. . . . . . . . . . . . . . .29

Delimitations. . . . . . . . . . . . . . . . . 29

Limitations. . . . . . . . . . . . . . . . . . .30

4. ANALYSIS OF DATA. . . . . . . . . . . . . . . . . 31

Results. . . . . . . . . . . . . . . . . . . .31

Discussion. . . . . . . . . . . . . . . . . . 37

4. SUMMARY AND CONCLUSION. . . . . . . . . . . . . .43

Summary of Results. . . . . . . . . . . . . . 43

Conclusion. . . . . . . . . . . . . . . . . . 44

Recommendation of Further Study. . . . . . . .45

REFERENCES. . . . . . . . . . . . . . . . . . . . . .47

APPENDIX. . . . . . . . . . . . . . . . . . . . . . 51

A. Borg Rate of Perceived Exertion (RPE) Scale. .51

B. YoYo Intermittent Endurance Test

Data Collection Form. . . . . . . . . . . . . 52

C. Parental Consent Letter. . . . . . . . . . . . 55

LIST OF TABLES

TABLES Page

1. Physical Characteristics of Hong Kong

Junior Team Handball. . . . . . . . . . . . . 31

2. Peak torque mean score of knees extensors. . .32

3. Peak torque mean score of knees flexors. . . .33

4. Pearson product moment coefficient of

correlation test between the distance

covered in the Level 2 YoYo Intermittent

Endurance Test and the muscle strength

of knee extensor. . . . . . . . . . . . . . .34

5. Pearson product moment coefficient of

correlation test between the distances

covered in the Level 2 YoYo Intermittent

Endurance Test and the muscle strength

of knee flexor. . . . . . . . . . . . . . . . .34

LIST OF FIGURES

FIGURES Page

1. The setting of YoYo Intermittent

Endurance Test. . . . . . . . . . . . . . . . . .27

2. The setting of Isokinetic Dynamometry. . . . .28

3. Scatter plots of the distance covered of

Level 2 YoYo Intermittent Endurance Test

and muscle strength of knee extensor. . . . . . 35

4. Scatter plots of the distance covered of

Level 2 YoYo Intermittent Endurance Test

and muscle strength of knee flexor. . . . . . . . . .36

Chapter 1

Introduction

Team handball is a dynamic sport that includes natural

athletic skills such as running, jumping, throwing, and

catching provide the action for the game (Fronske, 2008). It

can also be classified as an interval sport. As the needs of

physical fitness are vary and huge.

Muscular strength and endurance are the basic elements of

playing team handball. Strength and power are critical to the

performance of many athletic tasks. However, their assessment

is currently problematic because of the enormity of the area

and the limited work that has been completed within the field

to date (Gore, 2000).

On the other hand, technical and tactical skills in

handball are highly dependent on the player’s physical

capacity. In between the exchange of offense and defense,

players need aerobic endurance to perform a series of

movements and running in the handball court throughout the

match.

The YoYo tests are a number of tests which in an easy way

evaluates various aspects of performance. The tests contain

running activities that are relevant for many sports. Using

the YoYo tests, it is possible to obtain information about

a large number of athletes within a short time, and the tests

have higher performance validity during competition than

laboratory tests. There are three YoYo tests. They are YoYo

endurance test, YoYo intermittent endurance test and YoYo

Intermittent recovery test. For the YoYo intermittent

endurance test, it is to evaluate an individual’s ability to

repeatedly perform running intervals over a prolonged period

of time. The test is especially useful for the athletes who

perform interval sports such as tennis, team handball,

basketball, and soccer (Bangsbo et al., 2006).

Some Sport like ball games, in which the ball is used in

the fitness training, the exercise intensity for an athlete

varies continuously, and some overlap exists between aerobic

and anaerobic training (Bangsbo, 2005). The team handball

players need both anaerobic and aerobic ability for this

interval sport, quadriceps and hamstrings bear a great

workload of running, sprinting and jumping during the

competition.

Yoyo test is commonly used to assess individual’s

anaerobic capacity (ATPPCr) which is an essential energy

system utilized during handball competition. Since the test

requires individual to sprint repeatedly. I wonder if the

testing result was also determined by individual’s leg

strength.

Statement of Problem

The purpose of this study was to identify the contribution

of strength of knee extensor and flexor to the performance

of YoYo intermittent endurance test.

Hypothesis

The following hypotheses were tested in this study:

Research Hypothesis

There would be a significant relationship between the

muscles strength of knee extensor and flexor and the

performance of YoYo intermittent endurance test.

Null Hypothesis

The correlation between muscles strength of knee extensor

and flexor and the performance of YoYo intermittent endurance

test was not significant in participants.

Significance of the Study

As the player’s ability of muscular strengths and

endurances can be assessed and train at the same time, the

planning and pointed specific training can be established in

a diversity way. In order to have a better improvement and

performance on team handball players, it is worth to find out

the relationship between the performance of YoYo

intermittent endurance test and the strength power of the

quadriceps and hamstrings of the players.

Chapter 2

REVIEW OF LITERATURES

Muscular strength and endurance were important in most of

the sports. In this study, the purpose of this study was to

examine the contribution of strength of knee extensor and

flexor and the performance of YoYo intermittent endurance

test.

The review of literature was divided into six main

sections. The first section contained the importance of

muscular strength. Then the second section describes the

factors that would affect muscle strength. Third section shows

the testing method of strength. The information of YoYo

Intermittent Endurance Test and Isokinetic Systems would be

focused in the fourth and fifth section respectively. And the

summary was included in the last section.

The Importance of Muscular Strength

Strength is an important component of success in most

athletics events, and therefore should be an essential part

of most training programs. The time spent in training for

strength should be proportional to the requirement for these

components in your event, and your deficiencies in this area

(Heyward, 2006).

Nowadays, there are lots of physiological assessments and

methods for people to measure the muscles strength. Isokinetic

dynamometry is one of the assessments. It has been used to

assess elite athletes since its inception in the late 1960s,

for the different purposes. For two decades it has been the

standard research tool used by physiologists to investigate

dynamic muscle function of single muscle groups. Isokinetic

dynamometry can be performed under a range of conditions –

of angular velocity, positioning, range of motion,

contraction mode, movement sequence, and so on – from which

a wide range of measurement parameters can be derived (Gore,

2000). Especially for the jumping and shooting of team

handball, it requires the muscular strength of different body

parts such as arm, shoulder, wrist and leg.

The Importance of Leg Strength on Running Sports

Maximal power is demonstrated in athletic performances by

the ability to project an object or one’s body through apace.

Power produces momentum, which is the striking force when

contact is made. Thus power has many applications in a variety

of athletic events. In projecting an object, the object might

be thrown, kicked or struck, and the power is determined by

the combination of force and speed. For example, sprint

running is dependent largely upon power because it involves

a series of body projections, alternating from the two legs.

The rate of these projections is dependent upon the

combination of the force and speed of muscle contractions.

Power plays an even more prominent role in sprinting during

the acceleration phase than during the remainder of the sprint.

With consideration of the prevalence of sprinting,

acceleration, throwing, kicking, and impact in athletic

performances, the significance of power becomes apparent

(Fisher & Jensen, 1990).

Factors that Affecting Muscle Strength and Endurance

Muscle Length

According to Fisher & Jensen, the initial length of the

muscle is important because stretched fibers exert more force.

Apparently, in the stretched state, crossbridges are more

effectively aligned with active sites and maximal force can

be generated. Muscle fibers stretched beyond 120% of resting

length begin to decrease their tension. This condition seldom

exists in the human body, however, because muscle length is

limited by joint movement, and many fibers are about 120% of

resting length when joints reach their full extension. When

fibers are less than fully extended, there begins to be an

overlap of action filaments which interferes with the coupling

potential of the cross bridges (1990).

Angle of Pull

As the elbow joint moves through its range of motion, the

mechanical advantage increases and the force the muscle needs

to apply decreases yielding a rather stable “strength curve”

for the particular joint and muscle group. During elbow

flexion the greatest force is exerted between 80 and 140

degrees (180 degrees is full extension). At its strongest

point in terms of length, the force at the hand was only 74%

of maximum. In reality, the heaviest resistance that can be

moved through a full range of motion is not the load that can

be lifted at the optimal angle but the much smaller load at

the point of mechanical disadvantage when the muscle is

contracting maximally. Manufacturers have tried to compensate

for this effect by developing machines which provide variable

resistance so that maximal tension is being developed

throughout the range of motion (Fisher & Jensen, 1990).

Speed of Shortening

The relationship between muscular force and speed of

shortening is important to athletes, especially in limb

movements such as kicking and throwing. The faster a muscle

is contracted, the less time there is for crossbridge

coupling. The force generated by a muscle is greatest at the

slowest speeds of movement and decreases as the speed of

movement increases. Likewise, for any given force, the greater

the contribution of fast twitch fibers, the greater the

velocity of movement. Physiologically, fast twitch fibers

have a greater capacity for calcium release and uptake from

the sarcoplasmic reticulum which allows for faster tension

development. This information has pratical application in the

sense that athletes with a high genetic distribution of fast

twitch fibers will probably perform better in power type

events compared to those with predominantly slow twitch fibers


Coordination of Accessory Muscles

Strength is also related to the coordination of the

antagonistic muscles and the action of the neutralizer and

stabilizer muscles. These factors can be improved through

appropriate training which allows more efficient application

of muscular force (Fisher & Jensen, 1990).

Muscle Size

According to Fisher and Jensen, the contractile force of

a muscle is related to the muscle’s crosssectional

measurement (4 to 6 kg/cm 2 ). As strength increases, the size

of the individual muscle fibers increase, resulting in a

greater crosssectional area of the muscle. The increase in

size relates fairly well with the increase in strength. Other

factors may influence this relationship, such as the fat

around muscle, the proportion of active fibers, and the

efficiency of contraction. And muscle size and strength are

closely related and an increase in muscle size will result

in a significant increase in strength (1990).

Muscle Type

Fast and slow fibers are recruited selectively depending

on the force required. Training programs for strength

emphasize high resistance/low repetition movements to

stimulate recruitment of fast twitch fibers. For muscle

endurance, the resistance is decreased and the number of

repetitions are increased to allow slow twitch fibers to be

recruited. There may also be selective hypertrophy in fast

and slow fibers. Fast twitch fibers are much larger in power

athletes than in cross country runners (Fisher & Jensen,

1990).

Relationship of Strength to Age

Research, combined with practical experience, indicates

that under normal conditions boys increase in strength rather

consistently until the age of 25. After this age, strength

increase at a slower rate. Maximal strength is attained at

the age of 25. Soon after the maximal strength is attained,

strength begins to diminish. After the age 25, it is speculated

that a person loses 1% of his strength each year. At age 65

most persons are 65 to 70% as strong as they were at age 20

to 30. The rate of strength loss is influenced considerably

by one’s activity level throughout life (Fisher & Jensen,

1990).

According to Bassey, Bendall and Pearson (1988), the

decline in muscle strength associated with aging carries with

it significant consequences related to functional capacity.

A significant correlation between muscle strength and

preferred walking speed has been reported for both sexes. Also,

there is strong relationship between quadriceps strength and

habitual gait speed in frail institutionalized men and women

above the age of 86 yr supports this concept from the study

of Fiatarone et al. (1990).

Relationship of Strength to Sex

Women are about twothirds as strong as men and have about

twothirds as much muscle mass as men. They are about 80% as

strong as men in hip flexors and extensors, and about 55% as

strong in the forearm flexors and extensors. The difference

in upper and lower body strength between the sexes is probably

due to the difference in typical daily activity patterns,

although differences are diminishing. There is no evidence

to suggest differences in muscle quality between men and women


When strength is compared on an absolute score basis, men

are usually considerably stronger than women for all muscle

groups tested. These strength differences are particularly

apparent in comparisons of upper body strength, where women

are about 50% weaker than men; in lower body strength, women

are about 30% weaker (Heyward, JohannesEllis & Romer, 1986).

This sex characterization for strength is true regardless of

the device used to measure strength and is generally

attributed to the sexrelated difference in the distribution

of lean body mass (Castro & McCann, 1995). Exceptions are some

strengthtrained female trackandfield athletes and body

builders who significantly increase the strength of specific

muscle groups through resistance exercises (McArdle, Katch

& Katch, 1996).

Testing Methods of Strength

There are only two basic ways to test strength – statically

or dynamically. Static strength is easier to measure, but the

measurements are less valuable to athletes and coaches because

dynamic strength is the kind of strength that is most used

in athletic performance. In fact, the relationship between

isometric and dynamic strength measures are relatively low

and one should not be predicted from the other. Results of

most strength tests are also influenced by motivation. This

factor should be controlled whenever possible (Fisher & Jensen,

1990).

Static Strength Tests

Static strength of different body parts has been measured

accurately using a cable tensiometer, a back and leg lift

dynamometer, or a hand grip dynamometer. More recent

applications use a strain gauge and feed the information into

a personal computer. With either application, it must be

remembered that static strength varies at different points

through the range of motion. Therefore, if comparisons are

to be made, it is important that the strength be measured at

exactly the same angle each time (Fisher & Jensen, 1990).

Dynamic Strength Test

Maximal lifts with different kinds of weighttraining

equipment provide some of the best measures of dynamic

strength. A certain amount of experimentation is necessary

to determine the maximal weight that can be lifted for one

repetition, but when this is finally determined, it represents

the dynamic strength for that particular movement. Strength

can be measured by use of free lifting equipment,

weightlifting machines such as Nautillus or Universal gyms,

and isokinetic exercise devices such as the Cybex equipment


Isokinetic Systems

Isokinetic systems were conceived to analyse the muscular

fitness of patients who are members of any population group.

During a standard session, patients must perform a set of

exercise, for example, ten seconds extending and flexing their

leg with the machine moving at a constant speed of 90 deg/s.

The number of exercises and speed at which they must be

performed are determined by the isokinetic protocol currently

in use (CaracaValente & LopezChavarrias, 2000). This

protocol defines the number of exercises to be performed and

at what speeds. Obviously, the protocol must always be the

same, if we are to be able to analyse some patients against

others, as differences in the number, order and speed of the

exercises would significantly alter the isokinetic curves

obtained. All of the exercises performed in a session are

called an isokinetic test (CaracaValente & LopezChavarrias,

2000).

YoYo Intermittent Endurance Test

YoYo Intermittent Endurance Test. The test was performed

according to the methods of (Krustrup et al., 2003) and

consisted of repeated 20m runs forward and back, keeping in

time with a series of audio signals from a compact disc. After

completion of two 20m intervals, all subjects had 10 seconds

of active recovery, which consisted of 10 m of jogging around

a cone placed 5 m away from the starting point. The running

speed was progressively increased until the subjects reached

volitional exhaustion. The YoYo Intermittent Endurance Test

performance was taken as the total distance covered upon

volitional fatigue (Sirotic & Coutts, 2007).

Most team sports require athletes to regularly repeat short

highintensity bouts of exercise, interspersed with longer

intervals of submaximal exercise over a prolonged period of

time (i.e., > 30 minutes) (Reilly & Gilbourne, 2003). And this

test evaluates an individual’s ability to repeatedly perform

intervals over a prolonged period of time, particularly for

athletes from sports such as tennis, team handball, basketball

and soccer (Krustrup et al., 2003). YoYo Intermittent

Endurance Test was performed according to the methods of

Krustrup et al. (2003) and consisted of repeated 20m runs

forward and back, keeping in time with a series of audio signals

from a compact disc. After completion of two 20m intervals,

all subjects had 10 seconds of active recovery, which

consisted of 10 m of jogging around a cone placed 5 m away

from the starting point. The running speed was progressively

increased until the subjects reached volitional exhaustion.

The YoYo Intermittent Endurance Test test performance was

taken as the total distance covered upon volitional fatigue.

This test has previously been reported to be both a reliable

and valid test of physical performance in team sports

(Krustrup et al., 2003).

Definition of Terms

Strength

Strength is the maximal force you can apply against a load,

and power is proportional to the speed at which you can apply

this maximal force. Training to improve in this area can

include lifting weights, throwing heavier implements, running

against a resistance, and plyometrics (depth jumping and

bouncing). Strength is also defined as “the peak force of

torque developed during a maximal voluntary contraction (MVC),

under a given set of conditions (e.g. contraction type and

velocity)” (MacDougall, Wegner & Green, 1991). In more simple

terms, it is “the ability of a muscle group to exert maximum

contractile force against a resistance” (Heyward, 2006).

Muscular Strength

Muscular strength refers to the maximal force that can be

generated by a specific muscle or muscle group. Static or

isometric strength can be conveniently measured using a

variety of devices, including cable tensiometers and handgrip

dynamometers. Peak force development in such tests is commonly

referred to as the maximum voluntary contraction (MVC).

Isokinetic testing involves the assessment of muscle tension

generated throughout a range of joint motion at a constant

angular velocity. Equipment which allows control of speed of

joint rotation (degrees/sec) as well as physical

adjustability to test movement around various joints (e.g.,

knee, hip, shoulder, elbow) is available from several

commercial sources. Such device measure peak rotational force

or torque, defined as ‘the measured ability of a rotation

element to overcome turning resistance’ (Mahler et al., 1995).

Muscular Endurance

Muscular endurance is the ability of a muscle group to

execute repeated contractions over a period of sufficient time

duration to cause muscular fatigue, or to sufficient time

duration to cause muscular fatigue, or to statically maintain

a specific percentage of MVC for a prolonged period of time.

Simple field tests such as the 60second situp test or the

maximum number of pushups that can be performed without rest

may be used to evaluate the endurance of the abdominal muscle

groups and upper body muscles, respectively (Mahler et al.,

1995).

Torque

A torque is a vector that measures the tendency of a force

to rotate an object about some axis (Serway, 1996). The

magnitude of a torque is defined as force times its lever arm

(Tipler, 2004). Just as a force is a push or pull, a torque

can be thought of as a twist.

Peak Torque

Peak torque is simply equal to force, it was generated by

a muscle decreases with increasing velocities of movement.

The greatest torque is produced at the slowest speeds of

movement (Mathews & Fox, 1976).

Power

Power is the rate at which work is done – which is equivalent

to the product of torque and angular velocity (or force and

linear velocity). Average or instantaneous power can be

calculated (Gore, 2000).

Average Power

Average power (watt, W) is derived by dividing work (J)

by the time (duration) of the contraction (watt = joules/s).

This is equivalent to taking the mean of the product of

instantaneous torque (N.m) and instantaneous velocity (in

radians/s) at every time interval throughout the movement

(dimensionless radians are dropped, and the resultant N.m/s

= watts) (Gore, 2000).

Instantaneous Power

Instantaneous power (watts) is the product of torque and

the angular velocity (Gore, 2000).

Isokinetic Dynamometer

Isokinetic Dynamometer was used for the measurement of

resistance to passive movement of the knee joint (Supraja &

Singh, 2003).

Knee extensor and flexor

The recommended test position is seated, with hip flexion

angle of 80 degree. The knee extensionflexion axis is

approximated by aligning the dynamometer rotational axis with

the lateral femoral condyle. Restraint straps are applied for

the distal thigh, pelvis, and upper torso. The shin pad is

attached just above the lateral malleolus (Gore, 2000).

Isolated testing of the knee extensors may also sometimes

be performed in supine, with the hip in neutral (0 degree).

This position may be used for eccentric and concentric testing

of this muscle group. Axis alignment and stabilization are

often easier than in reciprocal concentricconcentric testing

of agonist and antagonist muscle groups; the direction for

the torque application is the same, and it bends to force the

thigh against the testing bench, thus providing efficient

stabilization (Gore, 2000).

Conversely, isolated testing of knee flexors may be

conducted in the prone position, also with the hip in neutral.

The consistent direction of torque application for eccentric

and concentric testing of this muscle group again aids in

stabilization (Gore, 2000).

Summary

For the team handball players, jumping, sprinting, agility

and repeatedly running ability were the determined skills with

their performance. So the test of muscles (knee

extension/flexion) strength can be a prediction index of their

performance in team handball. The present study was to access

the contribution of the performance of YoYo Intermittent

Endurance Test and the strength power of the quadriceps and

hamstrings of the players.

Chapter 3

METHOD

The purpose of this study was to examine the contribution


of YoYo intermittent endurance test. This chapter was divided

into the following parts: (a) subjects; (b) procedures; and

(c) method of analysis.

Subjects

The study included a total of 7 male elite youth team

handball subjects aged between 14 and 18 years. Participants

were fully informed of all possible risks and stresses

associated with the project and signed consent forms prior

to participation. They had to participate in the Isokinetic

Dynamometry Muscle Strength Test and YoYo Intermittent

Endurance Test. The study was conducted according to the Dr.

Stephen Hui Research Centre for Physical Recreation and

Wellness and was approved by Handball Association of Hong Kong,

China responsible. All subjects have been trained by the same

head coach and represent Hong Kong Junior Handball Team.

Procedures

In this study, level 2 YoYo Intermittent Endurance Test

and Isokinetic Dynamometry were used to measure the

performance of YoYo test and the muscle strength of knee

extensor and flexor respectively to assess the correlation

of strength of knee extensor and flexor and the performance

of YoYo intermittent endurance test. The YoYo Intermittent

Endurance Test was conducted at Dr. Stephen Hui Sports Hall

and the laboratory of Dr. Stephen Hui Research Centre for

Physical Recreation and Wellness was used to conduct the peak

torque of knee extensor and flexor by using Isokinetic

Dynamometry (Humac Norm Testing & Rehabilitation System) with

22 degree temperature and 70% relative humidity respectively.


YoYo Intermittent Endurance Test is to evaluate an

individual’s ability to repeatedly perform intervals over a

prolonged period of time. In this study, level 2 YoYo

Intermittent Endurance Test and Isokinetic Dynamometry were

tested in two days apart. All of the subjects were given a

trial before this study, to eliminate the learning effect.

And all of them were familiarized with the testing procedures

before data collection. 10minutes warm up was required before

the test. It includes 5minutes running on the treadmill with

moderate speed and 5minutes stretching exercise.

Test Protocol


Use cones to mark out three lines as per the Figure 1 below;

20 meters and 5 meters apart. The subject starts on or behind

the middle line, and begins running 20 m when instructed by

the cd. This subject turns and returns to the starting point

when signaled by the recorded beep. There is a active recovery

period (10 seconds respectively for the endurance and recovery

versions of the test) interjected between every 20 meter (out

and back) shuttle, during which the subject must walk or jog

around the other cone and return to the starting point. Verbal

encouragement was given by instructors in order to motivate

the subjects to their maximal ability. A warning is given when

the subject does not complete a successful out and back shuttle

in the allocated time, the subject is removed the next time

they do not complete a successful shuttle. The athlete’s score

is the total distance covered before they were unable to keep

up with the recording (Krustrup et al., 2003).

Figure 1.

The setting of YoYo Intermittent Endurance Test

Isokinetic Dynamometry

All the patients were informed about the experiment’s

procedure and positioned properly by adjusting the height of

the dynamometer persuing congruence between the dynamometer’s

axis and the axis of the knee joint. Subjects were stabilized

by restraining straps at the level of the chest, around the

abdomen and thigh. The force acceptance unit was attached 5

cm above the lateral malleolus. Test program is selected after

feeding in the general information about the subject, joint

tested, movements (flexion and extension) tested and side

tested. After setting the range of motion, the evaluation mode

is turned into passive mode (Supraja & Singh, 2003).

Resistance to passive movement of the knee joint during

flexion and extension, measured as eccentric torque is

recorded at speeds of 60 deg/s with resting period of 10 seconds

and 5 repetitions for each leg. Comparison of the relative

strengths of the different sides of the body, or agonists

versus antagonists (e.g. quads & hamstrings) can show specific

muscular limitations. Maximal torque value was measured in

this study (Figure 2).

Figure 2.

The setting of Isokinetic Dynamometry

Statistical Analysis

Ordinary statistical methods were used for the calculation

of mean, standard deviations and Pearson productmoment

correlation coefficients. Pearson Product Moment Coefficient

of Correlation (r) was used to examine the relationship

between the performance of the Level 2 YoYo Intermittent

Endurance Test and the knee muscle strength. Statistical

significance was set p

and Wellness.

4. The Isokinetic Dynamometry and YoYo Intermittent

Endurance Test were tested in two days apart.

Limitations

The following limitations were understood for the purpose

of interpreting this study:

1. The study could not control other variables that might have

affected the results of isokinetic dynamometry, such as

injury, daily life activities, dietary habit and sickness.

2. The performance of the subjects might vary due to their

different physical characteristics.

3. The performance of YoYo Intermittent Endurance Test and

Isokinetic Dynamometry might be influenced by the

uncontrolled motivation and effort by the subjects.

4. The results could only apply for the subjects who

participate in this study.

Chapter 4

ANALYSIS OF DATA

Results

Seven male Hong Kong junior team handball team players were

invited to participate in this study. The purpose of this study

was to examine the contribution of strength and endurance of

knee extensor and flexor and the performance of YoYo

intermittent endurance test. All the subjects participate in

two tests, level 2 YoYo intermittent endurance test and

Isokinetic dynamometry within the same week. The physical

characteristics of the subjects were summarized in Table 1.

Table 1

Physical Characteristics of Hong Kong Junior Team Handball

Team (N = 7)

Variables Minimum Maximum Mean ± SD

Age 14.00 18.00 15.43 ± 1.40

Weight(kg) 53.90 80.20 68.36 ± 9.86

Height(cm) 167.00 187.00 180.14 ± 7.71

The total distance covered in YoYo Intermittent Test from

the subjects was ranged from 640m to 1840m. The mean and

standard deviation of the distance were 1131.43 ± 399.14.

The peak torque mean score of both knees extensors and

flexors were shown in Table 2 and Table 3 respectively.

Table 2

Peak torque mean score of knees extensors (N = 7)

Subject Right Extensor Left Extensor Sum of the

Torque Score

1 188.00 Nm 179.00 Nm 183.50 Nm

2 197.00 Nm 197.00 Nm 197.00 Nm

3 275.00 Nm 245.00 Nm 260.00 Nm

4 167.00 Nm 156.00 Nm 161.50 Nm

5 297.00 Nm 260.00 Nm 278.50 Nm

6 133.00 Nm 99.00 Nm 116.00 Nm

7 241.00 Nm 221.00 Nm 231.00 Nm

Table 3

Peak torque mean score of knees flexors (N = 7)

Subject Right Flexor Left Flexor Sum of the

Torque score

1 142.00 Nm 114.00 Nm 128.00 Nm

2 127.00 Nm 121.00 Nm 124.00 Nm

3 176.00 Nm 148.00 Nm 162.00 Nm

4 104.00 Nm 73.00 Nm 88.50 Nm

5 183.00 Nm 167.00 Nm 175.00 Nm

6 87.00 Nm 87.00 Nm 87.00 Nm

7 164.00 Nm 132.00 Nm 148.00 Nm

The Pearson Product Moment Coefficient of Correlation

between the distance covered in level 2 YoYo Intermittent

Endurance Test and the muscle strength of knee extensor and

flexor was computed. The Pearson correlation coefficient and

the coefficient of determination were shown in Table 4 and

Table 5 respectively.

Table 4.

Pearson product moment coefficient of correlation test

between the distance covered in the Level 2 YoYo Intermittent

Endurance Test and the muscle strength of knee extensor (N

= 7)

Level 2 YoYo

Intermittent r r 2 p

Endurance Test

Distance Covered 0.491** 0.241 0.263

** Correlation is significant at the 0.01 level (2tailed).

Table 5.

Pearson product moment coefficient of correlation test

between the distance covered in the Level 2 YoYo Intermittent

Endurance Test and the muscle strength of knee flexor (N =

7)

Level 2 YoYo

Intermittent r r 2 p

Endurance Test

Distance Covered 0.401** 0.161 0.372

** Correlation is significant at the 0.01 level (2tailed).

Figure 3 showed the relationship between the distance

covered of Level 2 YoYo Intermittent Endurance Test and

muscle strength of knee extensor for all the subjects.

Figure 3.

Scatter plots of the distance covered of Level 2 YoYo

Intermittent Endurance Test and muscle strength of knee

extensor (N = 7)

Figure 4 showed the relationship between the distance

covered of Level 2 YoYo Intermittent Endurance Test and

muscle strength of knee flexor for all the subjects.

Figure 4.

Scatter plots of the distance covered of Level 2 YoYo

Intermittent Endurance Test and muscle strength of knee flexor

(N = 7)

By using the Pearson product moment coefficient of

correlation, the results shown that the contribution between

the distance covered of Level 2 YoYo Intermittent Endurance

Test and muscle strength of knee extensor and flexor was not

significant (r = 0.491, p > 0.05) and (r = 0.401, p > 0.05).

Hence there was null significant correlation between the

distance covered of Level 2 YoYo Intermittent Endurance Test

and muscle strength of knee extensor and flexor. According

to Figure 3 and 4, it shown that there was no significant

correlation between the distance covered of Level 2 YoYo


extensor and flexor. Since the coefficient of determination

are 0.241 (r 2 = 0.241) and 0.161 (r 2 = 0.161) respectively, the

variance shared by or common to the variables are 24.1% and

16.1%. It shown that there are lack of contribution between

the distance covered of Level 2 YoYo Intermittent Endurance

Test and muscle strength of knee extensor and flexor.

Discussion



of YoYo intermittent endurance test. The following

discussion will be divided into two parts: a) Relationship

between the performance of Level 2 YoYo Intermittent

Endurance Test and muscle strength of knee extensor and flexor,

and b) Factors that affect the performance of the test.

Relationship between the performance of Level 2 YoYo


extensor and flexor

As the previous study seldom use the power of muscular

strength to compare with muscular endurance performance due

to the different type of muscle ability. And there are lack

of data approve on Level 2 YoYo Intermittent Endurance Test

whether it have the positive relationship with muscle strength.

In this study, the finding shown that there are no relationship

between the performance of Level 2 YoYo Intermittent

Endurance Test and muscle strength of knee extensor and flexor

(r = 0.491, p > 0.05, n = 7) and (r = 0.401, p > 0.05, n

= 7). As the coefficient of determination are 0.241 (r 2 = 0.241)

and 0.161 (r 2 = 0.161) respectively, the variance shared by

or common to the variables are 24.1% and 16.1% only. It shown

the contribution of muscle strength of knee extensor and

flexor are just 24.1% and 16.1% to the performance of Level

2 YoYo Intermittent Endurance Test.

The objective of this study was to find out the relationship

between different types of ability of the subjects. Different

muscle fiber types may be one of the factors that cause the

result of no significance in this study. There were three

muscle fiber type, slow twitch fiber, type I fast twitch fiber

and type II fast twitch fiber. Although most of the sports

required both three types of muscle fibers, slow twitch fiber

was typically dominant in the endurance exercises, and two

fast twitch fibers were mainly in the strength exercises. For

muscle strength, it required mainly on the fast twitch fiber

in order to perform high intensity movements. So the

isokinetic dynamometry used to test the ability of muscle

strength with explosive power of the knee. It related to the

muscle length, high speed of energy production, muscle size

etc. On the other hand, muscle endurance was mainly required

the slow twitch fiber. The function of this slow twitch fiber

was totally different from the fast twitch fiber, it used to

perform a prolonged exercise with lower intensity. It mainly

referred to the ability of utilization of gas, gas exchange,

cardiovascular system, muscle tolerance and delivery of

oxygen to muscle through blood transfer etc. As this study

was to examine these two opposite types of ability of the body,

the correlation between the two tests may be weak.

Factors that affect the performance of the test

In this study, it requires subjects to pay their maximum

effort on the two tests. It was too difficult to ensure the

subjects perform their maximal effort during the test. Verbal

motivation can only push them to perform a better result, but

may not be the best result of them. Uncontrolled motivation

may be one of the factors that there was no significance in

the study.

Running skills in YoYo test may also influence the results.

The performance of level 2 YoYo Intermittent Endurance Test

may affected by the various turning skills and inconsistent

speed. The variation of different turning skills may affect

the muscle endurance, because the ineffective turning

required more energy expenditure. And so as to the

inconsistent speed by failure to catch up with the “bip” sound

during the YoYo Intermittent Endurance Test. These problems

may affect the accuracy of the results.

On the other side, there was extremely different body size

between subjects. The range different of height was 20 cm,

it was a great deviation on assessing the ability of the

subjects. When two people with 20 cm height different within

a small group of subject, it may have a great ability

discrepancy. For instances, the distance of each running step,

the number and size of muscle, lung volume, loading of heart

and power output etc. Those factors may influence the results

of level 2 YoYo Intermittent Endurance test a lot. Also,

referred to the above results shown in Table 2 and 3, the

strength power had obviously different in performance. The

greatest extensor torque score was 278.50 Nm, compare with

the lowest score 116.00 Nm, it over twice of the lowest score.

It shown that the individual different within the subjects

was great, due to the different growth period.

The performance of YoYo Intermittent Endurance Test and

Isokinetic Dynamometry might be influenced by the daily

activities by the subjects. Daily activities include dietary,

sleeping habit, examination period in school, training

intensity on the day before the test, injury and sickness.

As most of the subjects were students and they participate

in the tests after school. Tiredness may occur due to the school

work and some of them were having examination during the

testing period, it may not ensure the performance would be

the best of them. Eating before the test also may affect the

result’s accuracy.

Chapter 5

SUMMARY AND CONCLUSION

Summary of results


of strength of knee extensor and flexor and the performance

of YoYo intermittent endurance test.

7 male players of the Hong Kong Junior Team Handball Team

participated in this study. The muscle strength of knee

extensor and flexor, the Isokninetic Dynamometry was

conducted at the laboratory of Dr. Stephen Hui Research Centre

for Physical Recreation and Wellness. The performance results

of level 2 YoYo Intermittent Endurance Test was conducted

at the Dr. Stephen Hui indoor sports hall with recorded the

total distance covered of each subject. All the collected data

were analyzed by the Statistical Package for Social Science

(SPSS) version 16. Pearson Product Moment Coefficient of

Correlation (r) was used as well with the 0.05 level of

significance.

The results of this study were summarized as follows:

1. There was no significant relationship between the

muscle strength of knee extensor and flexor and the

performance of YoYo intermittent endurance test, at

the 0.01 level of significance (r = 0.491, p > 0.05)

and (r = 0.401, p > 0.05) respectively.

2. The contribution of muscle strength knee extensor and

flexor are 24.1% and 16.1% to the performance of level

2 YoYo Intermittent Endurance Test (r 2 = 0.241) and (r 2

= 0.161) respectively.

Conclusion

The finding shown that there are no relationship between

the performance of Level 2 YoYo Intermittent Endurance Test

and muscle strength of knee extensor and flexor. The

coefficient of determination are 0.241 (r 2 = 0.241) and 0.161

(r 2 = 0.161) respectively. As the contribution of muscle

strength of knee extensor and flexor are just 24.1% and 16.1%

only to the performance of Level 2 YoYo Intermittent

Endurance Test. The correlation between muscle strength of

knee extensor and flexor and the performance of Level 2 YoYo

Intermittent Endurance Test were weak.

Recommendation of Further Study

Based on the study, the following recommendations are

presented for the further study:

1. For the Isokinetic Dynamometry, it is better to use more

different speeds and force protocols (add 2 more speed which

are 180 deg/s with resting period of 10 seconds and 5

repetitions and 240 deg/s with resting period of 10 seconds

and 15 repetitions) to acquire different types of data.

Different speeds of the peak torque can show the different

ability (muscular strength and muscular endurance) of the

specific muscle group. So that it not just investigate the

relationship between muscular strength and the performance

of YoYo Intermittent Endurance Test.

2. It is better to measure the muscular strength and endurance

of calf.

3. Sample size should be enlarged in order to conduct a more

representative research.

4. The control of dietary, exercise and sleeping habit of the

subjects should be executed consistently.

REFERENCES

Bangsbo, J. (2005). Aerobic and anaerobic training in soccer –

with special emphasis on training of youth players.

Bagsvaerd: HO & Strom.

Bangsbo, J., Mohr, M., Poulsen, A., PerezGomez, J., &

Krustrup, P. (2006) Training and testing the elite athlete.

Journal of Exercise Science & Fitness, 4(1), 4.

Bassey, E. J., Bendall, M. J., & Pearson, M. (1988). Muscle

strength in the triceps surae and objectively measured

customary walking activity in men and women over 65 years

of age. Clinical Science, 74, 8589.

CaracaValente, J. P. & LopezChavarrias, I. (2000).

Discovering similar patterns in time series. Proc. Of the

symposium of the ACM for Applied Computing. 497505.

Castro, M. J. & McCann, D. J. (1995). Peak torque per unit

crosssectional area differs between strengthtrained and

untrained young adults. Medicine and Science in Sports and

Exercise, 27, 397.

Fiatarone, M. A., Marks, E. C., Ryan, N. D., Meredith, C. N.,

Lipsitz, L. A., & Evans, W. J. (1990). Highintensity

strength training in nonagenarians: effects on skeletal

muscle. Journal of the American Medical Association, 263,

30293034.

Fisher, A. G., & Jensen, C. R. (1990). Scientific basis of

athletic conditioning (3 rd ed). Philadelphia: Lea &

Febiger.

Fronske, H. A. (2008). Teaching cues for sport skills for

secondary school students. San Francisco: Pearson

Benjamin Cummings.

Gore, C. J. (2000). Physiological tests for elite athletes.

Champaign, IL: Human Kinetics.

Heyward, V. H. (2006). Advanced fitness assessment and

exercise prescription. Champaign, IL: Human Kinetics.

Heyward, V. H., JohannesEllis, S. M., & Romer, J. F. (1986).

Gender differences in strength. Research Quarterly for

Exercise and Sport, 57 (2), 154159.

Krustrup, P., Mohr, M., Amstrup, T., Rysgaard, T., Johansen,

J., Steensberg, A., Pedersen, P. K. & Bangsbo, J. (2003).

The YoYo Intermittent Recovery test: Physiological

response, reliability, and validity. Medicine and Science

in Sports and Exercise, 35, 697705.

MacDougal, J. D., Wegner, H. A. & Green, H. J. (1991).

Physiological testing of the high performance athlete.

Champaign, IL: Human Kinetics.

Mahler, D. A., Froelicher, V. F., Miller, N. H. & York, T.

D. (1995). ACSM’s guidelines for exercise testing and

prescription (5 th ed). Baltimore: Williams & Wilkins.

Mathews, D. K. & Fox, E. L. (1976). Physiological basis of

physical education and athletics (2 nd ed). Philadelphia:

Saunders College Pub..

McArdle, W. D., Katch, F. I. & Katch, V. L. (1996). Exercise

Physiology: energy, nutrition, and human performance (4 th

ed). Baltimore: Williams & Wilkins.

Reilly, T. & Gilbourne, D. (2003). Science and football: A

review of applied research in the football codes. Journal

of Sports Science, 21, 693705.

Serway, R. A. (1996). Physics for scientists and engineers.

Philadelphia: Saunders College Pub..

Sirotic, A. C. & Coutts, A. J. (2007). Physiological and

performance test correlates of prolonged, highintensity,

intermittent running performance in moderately trained

women team sport athletes. Journal of Strength and

Conditioning Research, 21 (1), 138144.

Supraja, M. & Singh, U. (2003). Study of quantitative

assessment of spasticity by isokinetic dynamometry.

Indian Journal of Physical Medicine and Rehabilitation.

1518.

Tipler, P. (2004). Physics for scientists and engineers:

mechnics, oscillations and waves, thermodynamics (5 th ed).

New York: W.H. Freeman.

APPENDIX A

運動感覺測量表

6

7 非常, 非常輕鬆

8

9 非常輕鬆

10

11 尚算輕鬆

12

13 少許辛苦

14

15 辛苦

16

17 非常辛苦

18

19 非常, 非常辛苦

20

APPENDIX B

YOYO INTERMITTENT ENDURANCE TEST DATA COLLECTION FORM

TEST SCHEME: YOYO INTERMITTENT ENDURANCE TEST – LEVEL 2

Date: Name:

Speed level: Intervals:

1.______________________________________________________

2.______________________________________________________

3.______________________________________________________

4.______________________________________________________

5.______________________________________________________

6.______________________________________________________

7.______________________________________________________

8.______________________________________________________

9.______________________________________________________

10. _____________________________________________________

11. _____________________________________________________

12. _____________________________________________________

13. _____________________________________________________

14. _____________________________________________________

15. _____________________________________________________

16. _____________________________________________________

17. _____________________________________________________

18. _____________________________________________________

19. _____________________________________________________

20. _____________________________________________________

Documents

ELITE JUNIOR HANDBALL PLAYERSlibproject.hkbu.edu.hk/trsimage/hp/06000851.pdf · handball are highly dependent on the player’s physical capacity. In between the exchange of offense