THE EFFECTS OF FREE WEIGHTS AND ELASTIC

TUBING RESISTANCE TRAINING ON PHYSICAL

SELF-PERCEPTION IN ADOLESCENTS

By: John, Adam, and Andrew

Purpose To explore the effect of free weights and elastic tubing

resistance training on physical self-perception in adolescents.

Hypotheses:

Adolescents in both resistance training groups would significantly increase their physical self-perception over the study period and that these changes would be associated with reductions in body fat and increases in muscular strength.

Changes in physical self-perception would be larger among those in the free-weight tubing group.

Sampling Participants

Volunteer students in 9th and 10th gradeNo prior or current resistance training No medical conditions or physical injuries108 students; 56 boys and 52 girls

AssignmentRandom assignment into 1 of 3 groupsStratified by gender and year group to reach

equal numbers in each group

Groups

1 free weight resistance training group22 boys and 15 girls

1 elastic tubing resistance training group20 boys and 21 girls

1 control group14 boys and 16 girls

Procedure

All groups were told not to change their diet

Control group was told not to do any resistance training

All 3 groups were told to keep the same level of physical activity as before

Participated in progressive resistance training programsTwice weekly 8 weeks long

Procedure

Participants completed two sets of 8-12 repetitions for 10 exercises

10-12 repetitions for weeks 1-48-10 repetitions for weeks 5-860-90 second rests in between each setEntire session lasted 40-50 minutes

Procedure Participants in free weight group used dumbbells,

barbells, and benches

Participants in elastic tubing group used the elastic tubing resistance training device known as the Gymstick

All participants used Borg’s rating of perceived exertion to judge their weight load (target load ranged from hard to very hard)

Asked to record all aspects of their sessions including volume and perceived exertion.

Procedure Measurements were completed at the study school using the

same instruments at each time point.

Measured muscular strength using a progressive repetition maximal lift in bench press and incline seated leg press

Measured height/weight to the nearest .1 kg/cm

Measured body composition using a bioelectrical impedance analyzer○ Students were asked to maintain normal hydration patterns

Participants also completed questionnaires before physical assessments to prevent the results from influencing their answers (pre and post test)

Procedure Completed the children’s physical self-perception profile

Contains five subscales: Sport competence, physical condition, strength, body attractiveness and overall physical self-worth○ Rated components of subcategories on a scale of 1-4

Also completed a resistance training self-efficacy and outcome expectancy survey

Answered questions such as: “If I participate in regular resistance training then it will help me increase my muscular strength”

Used the Likert scale 1-5 to assess their beliefs and self-efficacy regarding resistance training at baseline and post test○ 1 = strongly disagree and 5 = strongly agree

Results Physical self-perception did not change significantly

among boys

Physical self-perception only changed significantly for girls in one group

Free weight resistance training group Increase in body attractiveness

Relationship between reductions in body fat and physical self-worth and body attractiveness in boys and girls, respectively, was present, but not statistically significant.

Variables Independent

Resistance training○ Free weights or elastic tubing

DependentPhysical self-perception in adolescents

Relationship being examinedThe effects of free weights and elastic tubing

resistance training on physical self-perception in adolescents.

HypothesesAdolescents in both resistance training groups would

significantly increase their physical self-perception over the study period and that these changes would be associated with reductions in body fat and increases in muscular strength.

○ The results only slightly supported this; further study would be needed to fully support this hypothesis

Changes in physical self-perception would be larger among those in the free-weight tubing group.

○ Supported- The one group that had significant changes belonged to the free weight group

External Validity Generalizing to all adolescents

Sampling group was ages 14-15 and only drawn from one school in Australia.

Possible Threats

Could cultural differences account for either increases or decreases in physical self-perception in adolescents in different countries?

○ Countries like the U.S. place a lot of emphasis on body image

External Validity Threats Cont.

Could the fact that the participants were all volunteers influence the results?

○ The researchers admitted that those who would most benefit from the study were less likely to volunteer.

Could the age of participants (14-15) misrepresent the label “adolescents”? Would the results differ if the study included 16 or 17 year olds?

○ Adolescents at younger ages are usually not as confident; this could skew results.

Construct Validity Study Design

R O X1 O R O X2 O R O O

Independent Variable- Resistance training

They did a good job creating two levels of their construct

Also altered their routine halfway through the treatment period which further decreases likelihood of mono-operation bias

Interaction of different treatments and interaction of testing and treatment both do not apply

Construct Validity

Confounding constructs and levelsNot likely to be a threat, because both groups were

aiming for roughly 80% exertion rate.

Restricted generalizability across constructsTreatment was done during their lunch timeCould skipping lunch alter the results in one way or

another?○ Skipping meals would reduce overall caloric intake,

potentially reducing body fat more than the weight training programs would alone

Construct Validity

Dependent Variable- physical self perceptionMeasured construct in two different ways

which strengthens their resultsTested physical self-perception before

testing physical strength and body fat, eliminating the threat of lack of progress negatively skewing their self-perception scores.

Performed both a pre and post test

Construct Validity Possible threats

No reasonable threats to the construct validity aside from social threats○ Participants were encouraged to maintain the same

level of physical activity and caloric intake during the study as they had before

○ However, they were not required to record their daily food intake or physical activityThe participants might decide to do extra work in order to better

achieve the “desired” result.Or, is it possible that the participants were exercising more or

eating less subconsciously, since they weren’t required to keep track of their progress?- Either one of these potential situations would skew the results

Internal Validity The study was random assignment which

automatically eliminates single-group and multiple-group threats

Social Interaction ThreatsResentful demoralization

○ If the elastic tubing resistance group grows resentful of the free-weight training group it could impact their results.

○ The elastic tubing group could get bored with their treatment over time, affecting the amount of effort put forth

Internal Validity

Compensatory rivalry

The two treatment groups could become very competitive with each other, especially being high school students

However, despite these potential threats, it is unlikely that the internal validity would be compromised.