379

NORMATIVE ASSESSMENT TECHNIQUE

FOR BENCH PRESS AND LEG EXTENSION STRENGTH

IN COLLEGE FEMALES ON THE UNIVERSAL GYM

THESIS

Presented to the Graduate Council of the

North Texas State University in Partial

Fulfillment of the Requirements

For the Degree of

MASTER OF SCIENCE

by

Jean Gibson

Denton, Texas

August, 1983

- --- --

1984

DOROTHY JEAN GIBSON

All Rights Reserved

Gibson, D. Jean, Normative Assessment Technique for

Bench Press and Leg Extension Strength in College Females

on the Universal G Master of Science (Physical Edu-

cation), August, 1983, 44 pp., 6 tables, bibliography,

37 titles.

This study was to develop normative data of isotonic

muscular strength in college females using the Spartacus

model Universal Gym bench press and leg extension and to

control for the influence of body weight. Two hundred and

two college age females enrolled in weight training and

conditioning classes used the Universal Gym for twelve weeks.

Subjects were tested for maximum strength on 2 exercises and

their percent body fat was calculated. Pearson-product

moment correlations between lean body we ight , body weight

and the bench press test and the leg extension test were

correlated. After statistically controlling for the effects

of body weight, percentile ranks were calculated for both

tests.

y .. ,t1'.rr+n4 r: ,. .+. .': . :- :.. .,, .:v+--. >. ... : V/w kl t ,. _. .-... :,i -.. ;:, ::.. _. .x.,;. iwYiH ':"- _,- -.. .:. aus, :.. -'

TABLE OF CONTENTS

Page

LIST OF TABLES ........-.-........... iv

Chapter

I. INTRODUCTION . . . . . - - - - - . -"-"-"-"-"

II. REVIEW OF LITERATURE.............. 7

Nature of StrengthMeasurement of StrengthStructure of StrengthRelationship of Body Weight to StrengthStrength Research on WomenSummary

III. PROCEDURES . ................ 20

Selection of the SubjectsTesting EquipmentTest ProceduresPilot StudyStatistical Analysis

IV. RESULTS.. .......-.-.......... 25

Descriptive StatisticsRelationship Between the Anthropometric

Measures and the Strength TestsRegression Analysis and NormsTable III-IV Percentile Norms for Maximum

Bench Press Strength (lRM) atDifferent Body Weights

Table V-VI Percentile Norms for MaximumLeg Extension Strength (IRM) atDifferent Body Weights

V. DISCUSSION . - - -33

Utilizing the NormsSummary of the Present StudyConclusionsRecommendations

REFERENCES. .......-.-........ .......... 39

APPENDIX...........-.-.-.-.-.-..-. . . . ..- 43

III

r .4

LIST OF TABLES

Table Page

1. Descriptive Statistics ............... 25

2. Correlations Between the AnthropometricMeasures and the Strength Tests . .. . . 26

3. Percentile Norms for Maximum Bench PressStrength (lRM) at Different BodyWeights....... . . . . . . ......... 29

4. Percentile Norms for Maximum Bench PressStrength (1RM) at Different BodyWeights .................. ".-.. -.-.-.30

5. Percentile Norms for Maximum Leg ExtensionStrength (lRM) at Different BodyWeights......... ............... . 31

6. Percentile Norms for Maximum Leg ExtensionStrength (1RM) at Different BodyWeights... . .. . . ............ 32

iv

CHAPTER I

INTRODUCTION

Strength, the ability to apply or resist force, is

necessary to perform everyday tasks such as standing,

walking, opening a window, and carrying groceries.

Strength is also essential to the athlete who wishes to

perform at his/her best in athletic events from cycling,

swimming, tennis, and golf to those events of weight

lifting, shot putting, discus and hammer throwing (Lamb,

1978). To gain strength, many individuals train with

weights, which provide the necessary principles of inten-

sity and overload. More and more women are desiring to

physically exert themselves. Some wish to competitively

lift weights or to enhance performance in a particular

sport or to rehabilitate an injured body part. Predomi-

nantly, women desire to strength-train to add quality to

their lives, look and feel better, and consequently raise

their self-image (Westcott, 1982).

A review of the literature revealed that the majority

of strength studies performed on women described the

physical characteristics of women but did not develop

normative data on women's strength characteristics, which

1

2

the physical educator and strength trainer need. Recent

studies by Hosler, Morrow, and Jackson (1978) established

normative data for college women volleyball players using

the Cybex Power Bench and Power Leg Press. Percentile rank

norms for adult women on the Universal Gym were developed

at Arizona State University. Both of the aforementioned

studies derived their norms after statistically controlling

the effects of body weight (Baumgartner & Jackson, 1982).

A recent study by Patton, Jackson, and Watkins (1981)

established normative data for previously validated

measures of isotonic muscular strength in collegemales on

the Universal Gym while controlling for individual differ-

ences in body weight. A similar study is needed to develop

strength norms for women which control for body weight.

Strength can be assessed isometrically against a fixed

resistance, isotonically against a moveable object, or iso-

kinetically, in which the resistance is controlled at a

fixed speed. A large number of educational and other

institutions utilize the Universal Gym equipment as an

effective isotonic strength development apparatus which is

safe, convenient, and relatively inexpensive. Thus, the

development of strength norms for women which control for

individual differences in body weight using the Universal

Gym is valuable.

3

PURPOSE OF THE STUDY

The purpose of the study was to develop norms of

isotonic muscular strength in college females using the

Universal Gym and to control for the influence of body

weight. Past studies have substantiated that strength is

significantly correlated with body weight (Baumgartner &

Jackson, 1982; Berger, 1982; Clarke, 1945; Fleishman,

1964; Jackson & .Frankiewicz, 1975; and Wilmore, 1977).

Several researchers have indicated that body weight should

be statistically controlled when individual differences in

strength are to be assessed (Jackson, Watkins, & Patton,

1980).

Numerous investigators have shown that strength is a

multifaceted construct comprised of types of contractions

and body segments (Fleishman, 1964; Jackson & Frankiewicz,

1975; Liba, 1967). For example, in a recent study using

the Universal Gym, Jackson, Watkins, and Patton (1980)

identified that the bench press represented a valid upper

extremity isotonic strength measurement and that the leg

extension represented a valid lower extremity isotonic

strength measurement in college men.

To achieve the purpose of this study, isotonic

muscular strength measurements were assessed by obtaining

1 RMs (1 repetition maximum) on the bench press and leg

extension following the procedures employed by Berger

4

(1962) and supported by Jackson, Watkins, and Patton

(1980). Percent body fat was determined using skinfold

measurements, following steps recommended by Behnke and

Wilmore (1974) and Pollock and Jackson (1976). This

procedure allowed the delineation of the contributions of

body weight and lean body weight to individual differences

in strength among women and the development of the most

valid norms. This could prove useful since women have

higher levels of fat than men which would not contribute

to strength.

DELIMITATIONS

The study was delimited to college-age females being

tested for isotonic strength on the Spartacus model

Universal Gym bench press and leg extension apparati.

LIMITATIONS

The study was subjected to the following limitations.

1. Accurate 1 RM's on the bench press were restricted to

five pound increments.

2. Accurate 1 RM's on the leg extension were restricted

to 5 pound increments.

3. The subjects tested were enrolled in various condi-

tioning and weight training classes and followed

different conditioning procedures.

r

5

DEFINITIONS

1. 1 RM - repetition maximum - the maximum amount of

weight that can be lifted once through a full range of

motion; it is the criterion measure of maximum strength

in isotonic movements. (Berger, 1962)

2. Lean Body Weight (LBW) - body weight - the weight of

the body that is not fat, e.g., bone, muscle, skin,

etc. (Weinberg, Caldwell, Cornelius, Jackson, &

Smith, 1982)

3. Fat Body Weight (FBW) - absolute amount of body fat.

(Weinberg, et al., 1982)

4. Percent Body Fat (% body fat) - denotes percentage of

total body weight that is fat. (Weinberg, et al.,

1982)

5. Body Weight - lean body weight plus fat body weight.

(Weinberg, et al., 1982)

6. Bench Press - station on the Universal Gym in which

an individual maintains a supine position on the bench

and attempts to lift weights. Principal muscle

contractors are the pectoralis major and

triceps. (Weinberg, et al., 1982)

7. Leg Extension - station on the Spartacus model

Universal Gym in which an individual maintains a

seated position on the bench with his feet placed

on the lower pads of the leg machine. The subject

6

will attempt to extend her legs until they form a

straight line. Principal muscle contractors are the

rectus femoris, and vastus intermedius, lateralis,

and medialis (quadriceps). (Weinberg, et al., 1982)

CHAPTER II

REVIEW OF LITERATURE

In order to achieve the purpose of this study, namely,

establishing valid strength norms for women using the

Universal Gym, a review of related literature was conducted.

The areas covered were the nature of strength and the effect

that body weight has on it, and the concepts behind past

attempts in developing normative data on strength in women.

NATURE OF STRENGTH

Wilmore (1977) defines strength as the ability to apply

or resist force. It can be divided into two categories:

static and dynamic strength. Static strength is force

applied against a fixed resistance in which there is no

change in the angle of a joint or a movement in the

resistance. An example of a static or isometric

contraction would be to push against a wall. Dynamic

strength involves movement of the muscles, joints, and

the resistance, such as lifting a barbell. Dynamic

strength can be applied isotonically and isokinetically.

In isotonic movements, the resistance is constant

throughout the full range of motion. For example, when an

individual curls 130 pounds, the forearm flexors can exert

7

8

a force greater than 130 pounds, yet due to the mechanics

of the elbow joint, maximal contraction may only be exerted

at 30 and 150 degrees joint angles. Isokinetic movements

involve maximal contraction of the muscle group at a

constant speed through the full range of motion which is

accomplished by varying the resistance. The resistance is

controlled at fixed speed whatever the amount of strength

applied.

Static and dynamic movements can involve concentric

and eccentric contractions. Dynamic concentric

contractions involve muscle shortening while eccentric

contractions refer to muscle lengthening.. With a biceps

curl, lifting the weight with the arms fully extended to

a position of complete forearm flexion would be an example

of a dynamic concentric contraction. Lowering the weight

from the fully flexed position to the fully extended

position involves a dynamic eccentric contractions. A

static concentric contraction where there is no percept-

ible movement can be illustrated by a push or pull on an

immovable resistance or object. A static eccentric

contraction would be illustrated by holding a weight in

a fixed position (Wilmore, 1977).

MEASUREMENT OF STRENGTH

Strength can be assessed one of four ways: 1) tensi-

ometry, 2) dynamometry, 3) repetition maximum or 1 RM, and

9

4) computer-assisted force and work output determinations.

(McArdle, Katch, and Katch, 1981). Cable tensiometry

measures the pulling force of a muscle during a static or

isometric contractions. For example, to measure the

muscular force exerted during a knee extension, a band is

placed around a subject's lower leg which is attached to

a cable. As the subject begins to extend his leg, a force

is applied to the cable. As the force on the cable

increases, the riser, over which the cable passes, is

depressed which deflects the pointer and indicates a

strength score.

Dynamometers (e.g. hand-grip and back-lift) measure

static strength and operate on the principle of compression.

When a force is applied to the dynamometer, a steel spring

is compressed which moves a pointer and subsequently

indicates a strength score (McArdle, et al., 1981).

A dynamic method of assessing strength uses the one-

repetition maximum or 1 RM method. This refers to the

maximum amount of weight that can be lifted one time.

Berger's (1962) standardization of the 1 RM utilizes a

warm-up procedure and graded increases in resistance until

a failing attempt is observed. As an example, to assess

a subject's 1 RM on the bench press, a suitable starting

weight is selected close to but below the subject's maximum

lifting capacity. If one repetition is completed with full

extension of the arms, the subject would rest three to five

10

minutes at which time he would attempt to lift a load

increased by 10 pounds. This procedure would continue

until the subject failed to completely raise the load.

After three to five minutes of rest, the subject would

attempt to raise the load increased by five pounds. This

procedure is followed until the maximum is obtained

(Berger, 1962).

Modern technology provides the fourth way to measure

muscular strength, namely, the isokinetic dynamometer which

contains a speed-controlling device. Once the constant

speed is attained, the isokinetic loading mechanism

provides a counterforce equal to the muscle-generated

force. Consequently, maximum force can be applied during

all phases of the movement at a constant velocity. A load

cell inside the dynamometer monitors the level of applied

force and counteracting resistance and subsequently relays

the information to a recording device (McArdle, et al.,

1981). Thus, muscular strength can be assessed with iso-

metric, isotonic, and isokinetic contractions.

STRUCTURE OF STRENGTH

Past research has identified underlying factors of

muscular strength as measured by isometric, isotonic, and

muscular endurance exercises (Fleishman, 1961; Jackson &

Frankiewicz, 1975; Liba, 1967).

11

A review of related literature revealed that numerous

investigators have identified strength as a multifaceted

construct. Fleishman demonstrated that three factors are

associated with strength - "static strength", force exerted

against an immoveable object such as a dynamometer, "dynamic

strength", as measured by events such as pull-ups, rope

climb, and dips, and "explosive strength", as measured by

the standing broad jump, vertical jump, or medicine ball put

and that strength is related to body segments during iso-

metric contractions (Fleishman, 1964).

Liba's findings contradicted the three factor strength

model proposed by Fleishman. Liba reported nine underlying

factors of muscular strength that are related to body

segments and type of muscular contraction. An alpha factor

analysis identified two factors associated with body

projection, one factor identified by object-projection; one

factor represented by supporting the body weight; one factor

identified by two lunge items; and three factors represented

by five dynamometric strength variables. Liba delineated

that push and pull movements of the arm involve the muscles

of the upper trunk and are grouped with the trunk pull

distinct from hand and knee extension (Liba, 1966).

A recent Jackson, Watkins, and Patton (1980) study

identified the underlying structure of isotonic strength

in men as exhibited on the Universal Gym. Eighty-eight

college male subjects were tested on twelve selected

12

exercises using the Universal Gym: military press, bench

press, "lat" pull down, sit-ups, upright row, bent knee

ups, upper leg press, lower leg press, leg extension, leg

curl, lateral flexion, and hyperextension. One RMs were

assessed on each exercise with some procedural modifi-

cations being employed for the hyperextension, sit-ups,

bent knee up, lower leg press, and upper leg press lifts.

The raw data were analyzed with alpha and canonical factor

analyses. To control for the variance associated with

weight and height, second order partial correlations

between the isotonic strength measures were calculated.

The investigators postulated that statistical control of

the anthropometric differences of height and weight would

produce a clearer interpretation of the underlying factors

of strength. The correlations of the twelve strength

measures ranged from .091 to .872. The second order

partial correlations ranged from .044 to .841. Both alpha

and canonical factor analyses identified three factors:

Factor I related to upper extremity and trunk contractions,

Factor II related to lower extremity contractions, and

Factor III related to trunk and upper extremity

contractions. The study revealed that the bench press and

military press were the most valid upper extremity isotonic

strength measures for Factor I, and that the upper leg

press and lower leg press represented the most valid iso-

tonic strength measures for Factor II, and that lateral

,. ,,.. .r ,.u,;.M. .,, . , ,

13

flexion best represented Factor III. The leg extension

and leg flexion also possessed acceptable validity

coefficient. Factor III was not clearly delineated as a

trunk strength factor because of upper extremity

involvement (.Jackson, Watkins, and Patton, 1980).

RELATIONSHIP OF BODY WEIGHT TO STRENGTH

Many investigators agree that since strength is a

physical fitness component, it should be related to each

individual and it should be measured in relation to the

individual's body weight (Johnson & Nelson, 1979). Past

research has confirmed that body weight is moderately

correlated with strength and subsequently influences

accurate assessments of strength (Baumgartner & Jackson,

1982; Berger, 1962; Jackson & Frankiewicz, 1975; Jackson,

Watkins, and Patton, 1980; Johnson and Nelson, 1979; and

Mood, 1980).

Johnson and Nelson (1979) and Mood (1980) recommend

assessing an individual's relative strength by dividing

his body weight into the amount of weight he lifted in 1

execution to create a ratio. This ratio aLlows for

comparison between individuals of differing body weight

but does not statistically control for the effects of body

weight on strength.

In a study designed to clarify the factor structure of

muscular strength, Jackson and Frankiewicz (1975) hypoth-

esized that without controlling for the influence of body

14

weight, the delineation of the underlying factors of

strength would be unclear. To control for effect of body

weight, a residual score procedure was employed.

In a similar study, Jackson, et al. (1980) sought to

isolate the underlying factor structure of isotonic

strength in college men using the Universal Gym. Alpha

and canonical factor analyses were applied to the twelve

strength tests. When the raw data of the strength measures

were analyzed, a clear factor structure was not identified.

But when the variance associated with weight was eliminated

from the strength measures, three robust factors emerged

from the factor analyses.

Baumgartner and Jackson utilized the following

regression equations to assess women's strength (1 RM) on

the bench press:

Y' (bench press) = .355 (body weight) + 19.601

SE = 12.4

(Baumgartner & Jackson, 1982).

In conclusion, the preceding data suggested that iso-

tonic strength measurements could be validly obtained by

using upper and lower extremity strength measurements if

the effects of body weight was controlled.

STRENGTH RESEARCH ON WOMEN

Standardizing and simplifying the measurement of iso-

tonic strength has been a long-time goal of many investi-

15

gators. Establishing norms for isotonic exercises is

important because an isotonic muscular contraction is a

principal training method for the strength training physical

educator and teacher (Jackson, et al., 1981).

However, a review of literature revealed few studies

establishing strength norms for women. One of the earliest

investigators to develop standardized testing procedures

and norms for physical condition, athletic performance,

and muscular strength was Dr. Frederick Rand Rogers (Clarke,

1945). Rogers' PFI (physical fitness index) battery

comprises seven test items that stress most of the large

muscles of the body: forearms, upper arms, shoulder

girdles, back, and legs. Rogers' test of seven elements is

a reduction from the ten item test developed by Sargent.

Rogers' norm tables combine such variables as sex, age, and

weight for every two pounds and each half-year increase in

age. Two scores, the Strength Index (SI) and the Physical

Fitness Index (PFI) are utilized. The Strength Index is a

composite score obtained from six strength tests (arm

strength, composed of pull-ups and push-ups, leg strength,

back strength, left-grip strength and right-grip strength)

plus lung capacity. Its purpose is to measure general

athletic ability, not physical fitness (Clarke, 1945).

Rogers hypothesized that an individual with a high strength

index should have a higher athletic ability than an

individual with a low strength index. To obtain the PFI the

16

following formula is used:

Achieved SIPFI = NrSI x 100

Norm SI

For example, a twenty-two year old woman who weighs 144

pounds has an obtained Strength Index of 1905; her norm

Strength is 1814. Thus, 1905 divided by 1814, times 100,

equals a PFI of 105. A PFI of 100 is considered average

(Mathews, 1978).

Co .ger and Macnab (1967) compared the strength and

body composition of forty participants and 40 nonpartici-

pants in Women's Intercollegiate athletic program. The

40 participants were comprised of women involved in

swimming, basketball, volleyball, and gymnastics teams at

the University of Alberta. The nonparticipants were

enrolled in required physical education classes. The cable

tensiometer was used for all strength tests and individual

measures of shoulder flexion, shoulder extension, shoulder

horizontal flexion, forearm flexion and extension, ankle

flexion, hip flexion and extension, and knee extension.

Total strength was recorded as the total of nine strength

measures. Clarke' s technique for measuring strength was

the procedure followed and all measures were recorded in

pounds. As was hypothesized, the participants were found

to be significantly stronger than the nonparticipants in

all strength measures. The participants had a total

strength measure of 743.8 pounds and the nonparticipants

17

had a total of 606.0 pounds. The correlation between

weight and the toral strength was .40 and .31 for the

participants and nonparticipants respectively. It was

identified that body weight and lean body mass showed a

significant difference whereas percent body fat did not

(Conger & Macnab, 1967).

Zuti and Corbin (1977) developed normative data for

leg extension strength on 1533 freshman females without

accounting for height or weight. Normative data were

collected for right-hand grip strength and left-hand grip

strength, upper back strength, and leg extension strength

following Clarke procedures for dynamometer measures and

using isometric contractions (Zuti & Corbin, 1977).

Johnson and Nelson established ratio strength norms

for college women on the free weights at Corpus Christi

State University in 1976. The raw scores were calculated

by dividing an individual's body weight into the additional

weight lifted. The norms were based on the scores of 65

college women. The women were retested after nine weeks of

training to assess increases in strength. An example of

a score follows: if a woman who weighs 144 pounds can bench

press 75 pounds, then the ratio score obtained would equal

.51, which would fall into the intermediate performance

level after nine weeks of training (Johnson & Nelson, 1979).

Hosler, Morrow, and Jackson (1978) developed speed,

strength, and anthropometric norms of college women

18

volleyball players. Strength was measured with the Cybex

Power Bench and Power Leg Press with the score represented

as a maximum force exerted through a range of motion.

Following Behnke and Wilmore (1974) procedures, measures

for stature, bicromial diameter, and bi-iliac diameter were

taken using a GPM Swiss-made sliding caliper. Skinfold

measures were taken at the tricep, suprailiac, and thigh

using the Lange calipers following the procedures of Behnke

and Wilmore (1974). The thigh and suprailiac skinfolds were

weighted by a regression equation and were used to estimate

body density and subsequently, percent body fat. The norms

developed for strength on the bench press and leg press

accounted for body weight (Hosler, Morrow, and Jackson,

1978).

Finally, percentile rank norms for adult women on the

Universal Gym bench press were developed at Arizona State

University. One RM's were assessed and normative data was

presented for various body weights (Baumgartner & Jackson,

1982).

In conclusion, the data suggested that isotonic

strength measurements can be validly obtained by using

upper and lower extremity strength assessments if the

effects of body weights are controlled. Furthermore, a

large number of educational and other institutions

recognize the Universal Gym as an effective development

apparatus that is safe, convenient, space and time

19

efficient, and most of all, relatively inexpensive (Westcott,

1982). Consequently, a study designed to establish strength

norms for women using the Universal Gym was warranted.

CHAPTER III

PROCEDURES

Selection of the Subjects

Two hundred and two volunteering college age females

enrolled in weight training and conditioning classes at

North Texas State University, formed the sample in the study.

The weight training and conditioning classes selected for

the study were all using the Universal Gym apparatus for

the development of strength and all subjects had completed

12 weeks of conditioning at the time of data collection.

(See Appendix A - Informed Consent form).

Testing Equipment

The equipment used in the present study to assess

strength was the Spartacus model Universal Gym bench press

and leg extension machines. A Harpenden skinfold caliper

was used to assess subcutaneous fat.

Test Procedures

To assess the one repetition maximum (1 RM) on the

bench press and leg extension, Berger' s (1962) 1 RM

procedure was followed. After a standardized warm-up

period, which included 10 wall push-ups and 10 deep knee

20

21

bends, the subject lay supine on the bench, hands grasping

the bar, shoulder width apart, palms facing upward. A

suitable starting weight was selected close to but below the

subject's maximum lifting capacity. If one repetition was

completed with full extension of the arms, the subjects

rested three to five minutes, at which time the load was

increased by five pounds. This procedure continued until

the subject failed to completely raise the load.

To assess the 1 RM on the leg extension, the subject

sat down on the bench, placed her feet under the lower pads

of the leg machine, and held onto the bench, keeping her

back as straight as possible. A suitable starting weight

was selected close to but below the subject's maximum

lifting capacity by asking the subject what weight she knew

she could lift. If one repetition was completed with full

extension of the legs, the subject rested three to five

minutes at which time she attempted to lift a load 10 pounds

heavier. This procedure continued until the subject failed

to completely raise the load. The last successful lift was

as the subject's 1 RM. The aforementioned procedures were

supported by Jackson, et al. (1980).

To predict percent body fat, an individual's body

composition was assessed. Body composition consists of bone,

body fat, and lean body weight and is determined by assessing

body density.

22

Densitybody =_we:ightbody volumebody

Relative fat = 4 9 5/Densitybody - 450

(Siri, 1956). Laboratory methods of hydrostatic weighing,

radiographic analysis, potassium 40, and total body watet

determination are valid measurement techniques but are not

practical for mass or field testing. Thus, anthropometric

measurements including skinfold measurements have been used

to estimate body composition (Jackson & Pollock, 1976).

Behnke and Wilmore (1974) derived generalized equations that

allow the estimation of body composition and lean body weight

in young men and women. Also, Pollock and Jackson (1976)

followed suit by deriving multiple regression equations for

predicting body weight, fat, and lean body weight in men and

women. These equations provide the researcher with

techniques that can be applied to populations of different

ages and body composition, yet they are time consuming. To

decrease the amount of time spent calculating, Baun, Baun,

and Raven (1981) derived a nomogram based on Jackson and

Pollock's (1976) generalized equations for age and sum of

three skinfold values to determine percent body fat.

This study utilized Behnke and Wilmore (1974) procedures

of assessing skinfold measurements and Baun, Baun, and

Raven's (1981) nomogram to determine percent body fat.

The subject's weight was recorded, then using a

Harpenden skinfold caliper, skinfold measurements were taken

23

from the triceps, suprailium, and thigh. The mean of three

trials at each site were used as the final skinfold

measurement.

Pilot Study

To determine the objectivity and reliability of the

experimenter's testing procedures, a pilot study was

conducted. Subjects' (N=ll) bench press, leg press, percent

body fats were determined using the previously described

procedures. Reliability was established for the bench press

and leg extension measurements with correlations of .99 and

.92 between the trials, respectively. Also, no significant

differences were observed between trials. Reliability and

objectivity was established for percent fat values. A

correlation of .98 was calculated between the experimenter's

percent fat values and an experienced laboratory technician' s

values. No significant differences were found between the

sets of percent fat values. Also, the internal consistency

of the experimenter's skinfold assessments averaged .95.

Statistical Analysis

Pearson-product moment correlations between lean body

weight, body weight, and the bench press test and the leg

extension test were calculated. If the correlations were

statistically and physiologically meaningful, bivariate

regression equations were to be developed with body weight

24

predicting the strength tests. The equations followed:

Y1 = a1 + b1 (body weight)

Y2 = a2 + b2 (body weight)

where Y1 predicted bench press

Y2= predicted leg extension

(Glass & Stanley, 1970).

In order to calculate an individual's score with the

influence of body weight held constant, the residual scores

were determined with the following equations:

Bench press -Y1 = Yb-l

Leg Extension - Y2 Y1-2

where Yb-l = bench press with body weight held constant

Y 12 = leg extension with body weight held constant

(Baumgartner & Jackson, 1982). Finally, percentile rank

norms were developed for raw score 1 RM measurements, 1 RM' s

controlling for body weight.

CHAPTER IV

RESULTS

This chapter presents the descriptive statistics of

the study, the correlations showing the relationship

between the anthropometric measures and the strength tests,

and the generated norms and their applied use. The

descriptive statistics, including mean, standard deviation,

and standard error, are presented in Table I below.

Table I

Descriptive Statistics of the Variables Measures

Variable

Age

Weight

Percent body fat

Fat body weight

Lean body weight

Bench press

Leg extension

19.683

127.584

24.7

32.041

95.543

80.173

94.703

lbs

lbs

lbs

lbs

lbs

lbs

S .D.

I.512

17.899

5.6.

10.871

11.236

18.813

29.53

S.E.

0.106

1.259

.39

0.751

0.791

1. 183

2.078

25

26

Relationship between the anthropometric measures and the

strength tests

Pearson-product moment correlations between lean body

weight, body weight and the bench press test and the leg

extension test are presented in Table II.

Table II

Correlations Between the AnthropometricMeasures and the Strength Tests

Bench Press Leg Extension

Body weight .441 .458

Fat weight .095 .148

Lean body weight .571 .550

After examining the correlations, it was concluded that

even though lean body weight has a statistically higher

correlation to the strength measures than body weight, the

difference is not of sufficient magnitude to cause the

practitioner to become concerned with lean weight and fat

weight assessment. Also, the use of body weight to predict

strength is a more practical method for a teacher to use

because assessing lean body weight requires more time in

taking skinfold measurements.

The results of this study support past research

(Baumgartner & Jackson, 1982; Berger, 1982; Clarke, 1945;

Fleishman, 1964; Jackson & Frankiewicz, 1975; Wilmore,

27

1977 by confirming that body weight is related to strength

performance. In this study, a positive correlation was

found between body weight and the leg extension scores

(.458) and between body weight and the bench press scores

(.441). The mean percent body fat was calculated to be

24.7% which is in agreement with past research's

measurements of the average percent body fat in women

(Williams, 1983). The calculated mean body composition of

24.7% is evidence that the present study's sample is

typical of the average female population.

Regression Analysis and Norms

A simple linear regression analysis was used to

determine the least square equations with body weight

predicting the leg extension and bench press tests. The

equations follow:

Equation 1 - predicted bench press =

(.41035) body weight + 27.81903

Equation 2 - predicted leg extension

(.80115) body weight + 7.1096

In order to obtain a strength measure free of the influence

of body weight, a residual score method was used

(Baumgartner & Jackson, 1982). The third equation

demonstrates this method:

Equation 3 - y - y1 = y residual

where y is the actual strength score, y is the strength

28

score predicted from the individual's body weight and y

residual is the strength score which is uncorrelated with

body weight.

Percentile ranks were calculated on the y residual

scores for both tests. Predicted strength test scores were

calculated for individual body weights each 5 lbs from 85

lbs to 200 lbs. Appropriate corresponding residual scores

to percentile ranks 95% to 5% were added to the predicted

values to establish a norm referenced strength score that

holder body weight constant. Tables 3 - 6 present the results

of this procedure. For example, in examining Table IV, on

page 30, an individual who weighs 130 lbs and can bench

press 90 lbs would have a percentile rank of 75. The same

individual, if she lifted 130 lbs on the leg extension

machine, would have a percentile rank of 90.

29

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CHAPTER V

DISCUSSION

Utilizing the Norms

The reader should remember that the present study was

delimited to the Spartacus model Universal Gym bench press

and leg extension apparati. Since strength is a component

of physical fitness, many investigators contend that it

should be related to each individual' body weight. Some

researchers calculate a strength index by dividing an

individual's body weight into the additional weight lifted

(Johnson & Nelson, 1979) The problem with this technique

is that researchers have shown that body weight is only

moderately correlated with strength and thus affects

strength performance. The present study provides a more

valid method of assessing an individual's strength

performance by statistically controlling for the effect of

body weight on strength. Both teacher and strength trainer

can use these norms to evaluate performance and gain

immediate feedback which can serve as a motivation in itself.

For example, in evaluating the strength performance of a

student who weighs 120 1bs and can bench press 80 lbs, a

teacher can determine that the student ranks at the 60th

percentile and subsequently ascribe a grade. A student, on

33

34

the other hand, can see her improvement by determining her

starting percentile rank and her last percentile rank after

a training session of 6 weeks or more. AAHPERD's newly

developed health related fitness test recommends that when

using norm reference standards, the 25th and 50th percentiles

should be used as criterion to measure a student's

performance. In other words, the 25th percentile in each

test would be considered the minimal acceptable score and

students ranking below this level should be provided with

remedial training. AAHPERD also recommends that all

students should strive to attain the 50th percentile on all

test items. AAHPERD's method of interpreting norms could be

applied to this study's norms (Blair, Falls, & Pate, 1983).

Summary of the Present Study

In recent years, strength training has become common

practice for many individuals, including women. More and

more women desire to strength train to add quality to their

lives and consequently look and feel better, yet the

normative data has not been available to the strength

trainer which could give important feedback and serve as a

motivator. The development of normative data of isotonic

strength in college females is a desirable goal. Estab-

lishing norms for isotonic strength is important because

isotonic muscular contractions are a principal training

method for the strength training physical educator and

teacher (Jackson, et al., 1981).

35

A review of literature revealed that the majority of

the studies performed on women described the physical

characteristics but did not develop the normative data on

women's strength characteristics which the physical educator

and strength trainer need. Roger's PFI (physical fitness

index) norm tables combined the variables of sex, age, and

weight for every 2 lbs and each half-year increase in age

and used a Strength Index and physical fitness index as a

method to measure general athletic ability, not physical

fitness (Clarke, 1945). Conger and McNab (1967) compared

strength and body composition of 40 participants and 40

nonparticipants in Women's Intercollegiate Athletic Program.

A cable tensiometer was used to measure 9 strength tests.

Total strength was recorded as the total of the nine

strength measures. As was hypothesized, the participants

were found to be significantly stronger than the nonpartic-

ipants in allstrength measures. The correlation between

weight and the total strength was .40 and .31 for the

participants and nonparticipants, respectively.

Zuti and Corbin (1977) developed normative data for

leg extension on 1533 freshman women without accounting

for height or weight. Normative data were collected for

right-hand grip strength and left-hand grip strength, upper

36

back strength, and leg extension strength using dynamometer

measures and isometric contractions (Zuti & Corbin, 1977).

Johnson and Nelson (1976) established strength norms by

dividing an individual's body weight into the additional

weight lifted. Many investigators agree that since strength

is a physical component, it should be related to each

individual and it should be measured in relation to the

individual's body weight (Johnson & Nelson, 1979). Past

research has substantiated that body weight is significantly

correlated with strength and subsequently influences

accurate assessments of strength (Baumgartner & Jackson,

1982; Berger, 1962; Jackson & Frankiewicz, 1975; Jackson,

Watkins, and Patton, 1980; Johnson & Nelson, 1979; and Mood,

1980). In a recent study by Jackson, et al. (1980) designed

to study strength in men using the Universal Gym, the

researchers postulated that statistical control of the

anthropometric differences of height and weight would produce

a clearer interpretation of the underlying factors of

strength. Alpha and canonical factor analyses were applied

to the strength test. When the raw data of strength measures

were analyzed, a clear factor structure was not identified.

But when the variance associated with weight was eliminated

from the strength measures, three robust factors emerged

from the factor analyses. In conclusion, the preceding data

suggested that isotonic strength measurements in men can be

validly obtained by using upper and lower extremity strength

37

measurements if the effects of body weight are controlled.

The study also revealed that the bench press and leg

extension tests were valid isotonic measurements for upper

and lower extremity contractions, respectively. For the

purpose of the present study--to provide normative data on

isotonic strength in women using the Universal Gym bench

press and leg extension apparati while controlling for the

effects of body weight--a residual score procedure was

utilized.

The results of the present study demonstrated a

positive relationship between body weight and strength and

lean body weight and strength as was predicted. Even

though lean body weight had a higher correlation to strength

than body weight, the difference is not of sufficient

magnitude to cause a practitioner to become concerned with

lean weight and fat weight assessment. Thus, for the

practitioner, calculating LBW does not provide any more

information concerning the expression of strength--body

weight is sufficient. Percentile ranks were calculated on

the residual scores for both tests to provide a table that

both teacher and strength trainer can use to evaluate

strength performance and gain important feedback.

Conclusions

1) Since body weight is positively correlated with

strength, a residual score method was justifiably employed

.

38

to statistically control for the influences of body weight on

strength and valid norms were presented.

2) Both body weight and lean body weight were signi-

ficantly correlated with strength, yet the difference is not

of sufficient magnitude to warrant the calculation of lean

weight and fat weight. Thus, for the practitioner, body

weight can be used to validly predict strength performance

in a practical method.

3) The Spartacus model, Universal Gym can provide

reliable data for the purpose of evaluating strength

performance.

Recommendations

1) The sample size of the study could be increased

to improve the generalizability of the norms.

2) More strength norms could be established for women

by increasing the number of exercises tested on the

Universal Gym Spartacus model. For example, the arm curl

station could be used to test the biceps, brachialis and

brachioradialis, the lat pull station to test the

latissimus dorsi and biceps, and the leg curl station to

test the biceps femoris, semimembranosus, and semi-

tendinosus.

39

References

Baumgartner, T. A., & Jackson, A. S. Measurement in evalu-

ation in physical education (2nd ed.). Dubuque, Iowa:

Wm. C. Brown, 1982.

Baun, W. B., Baun, M. R., & Raven, P. B. A nomogram for the

estimate of percent body fat from genralized equations.

Research Quarterly, 1981, 52(3), 380-384.

Behnke, A. R., & Wilmore, J. H. Evaluation and regulation

of body build and composition. Englewood Cliffs,

New Jersey: Prentice-Hall, 1974.

Berger, R. A. Optimum repetitions for the development of

strength. Research Quarterly, 1962, 33(3), 334-338.

Berger, R. A. Applied exercise physiology. Philadelphia:

Lea & Febiger, 1982.

Blair, S. N., Falls, H. B., & Pate, R. R. A new physical

fitness test. The Physician and Sports Medicine,

Minneapolis: McGraw-Hill, 1983.

Clarke, H. H. The application of measurement to health

and physical education. New York: Prentice-Hall, 1945.

Conger, P. R., & McNab, R. B. Strength body composition,

and work capacity of participants and nonparticipants

in women's intercollegiate sports. Research Quarterly,

1967, 38(2), 184-191.

40

DeLorme, T. L., & Watkins, A. L. Progressive resistance

exercise. New York: Appleton-Century-Crofts, 1951.

Fleishman, E. A. The structure and measurement of physical

fitness. Englewood Cliffs, New Jersey: Prentice-Hall,

1964.

Glass, G. V., & Stanley, J. C. Statistical methods in edu-

cation and psychology. Englewood Cliffs, New Jersey:

Prentice-Hall, 1970.

Hosler, W. W., Morrow, J. R., & Jackson, A. S. Strength,

anthropometric, and speed characteristics of college

women volleyball players. Research Quarterly, 1978,

49(3), 385-388.

Jackson, A. W., Watkins, M., & Patton, R. W. A factor

analysis of twelve selected maximal isotonic strength

performances on the universal gym. Medicine and

Science in Sports & Exercise, 1980, 12(4), 274-277.

Jackson, A. S., & Frankiewicz, R. J. Factorial expressions

of muscular strength. Research Quarterly, 1975,

46(2), 206-217.

Jackson, A. S., & Pollock, M. L. Factor analysis and multi-

variate scaling of anthropometric variables for the

assessment of body composition. Medicine and Science

in Sports, 1976, 8(3), 196-203.

Johnson, B. L., & Nelson, J. K. Practical measurements for

evaluation in physical education (3rd ed.) .

Minneapolis: Burgess, 1979.

41

Lamb, D. R. Physiology of exercise: Responses and

adaptations. New York: Macmillian, 1978.

Mathews, D. K. Measurement in physical education (5th ed.).

Philadelphia: W. B. Saunders, 1978.

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

pysiology: Energy, nutrition, and human performance.

Great Britain: Henry Kimpton, 1981.

Mood, D. P. Numbers in motion. Palo Alto, California:

Mayfield, 1980.

Morrow, J. R., James, R., Jackson, A. S., Hosler, W. W.,

& Kachurik, J. K. The importance of strength, speed,

and body size for team success in women's intercol-

legiate volleyball. Research Quarterly, 1979, 59(3),

429-437.

Patton, R. W., Watkins, M., & Jackson, A. W. A normative

assessment technique for isotonic strength in college

males on the universal gym. American Corrective

Therapy Journal, 1981, 35(3), 78-81.

Weinberg, R. S., Caldwell, P., Cornelius, W., Jackson, A.,

& Smith, J. Health related fitness: Theory and

practice. Topeka, Kansas: Jostens Publications, 1982.

Westcott, W. L. Strength fitness. Boston: Allyn and

Bacon, 1982.

Williams, M. H. Nutrition for fitness and sport. Dubuque,

Iowa: Wm. C. Brown, 1983.

42

Wilmore, J. H. Athletic training andphysial fitness

Physiological principles arid practices ofthecorndi-

tioning process. Boston: Allyn and Bacon, 1977.

Zuti, W. B., & Corbin, C. B. Physical fitness norms for

college freshmen. Research Quarterl, 1977, 48 (2) ,

499-503.

APPENDIX A

43

44

Appendix A

Informed Consent

1. The purpose of this study is to develop norms of isotonic

muscular strength in college age women using the

Universal Gym leg extension and bench press machines and

to statistically control for the influence of body

weight. You will be asked to execute a 1 RM (1 maximum

lift) on the bench press and on the leg extension. Your

skinfold measurements will be assessed using a Harpenden

skinfold caliper and subsequently be used as part of the

data needed to develop the norms.

2. I have (seen, heard) a clear explanation and understand

the nature and purpose of the procedure treatment. I

understand that the procedure to be performed is invest-

igational and that I may withdraw at any time with my

class grade not being affected as a result of my

withdrawal. With my understanding of this and having

received satisfactory answers to the questions I have

asked, I voluntarily consent to the procedure or

treatment in paragraph 1 above.

Signed: Date:'

Witness: