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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.