PEDS 409 Research Design: True Experimental

BY: Sherri Beauchamp, Marie Buchta, Avaleigh Wagner & Jodi

Spink

Li, F. et al. (2001) Tai Chi Enhances Self-Efficacy andExercise Behavior in Older Adults. Journal of Aging and Physical Activity (9): 161-171.

Authors and Affiliations

Fuzhong Li: Oregon Research InstituteEdward McAuleyPeter HarmerTerry E. DuncanNigel R. ChaumetonGrants from: National Institute on Drug

Abuse and National Institute on Aging

Research Question

What are the effects of a Tai Chi

intervention program on perceptions of

personal efficacy and exercise behavior

in older adults?

Type of Research

True Experimental

One or more control groups AND one or more

treatment groups

Random assignment from population of interest

Variables of interest can be manipulated directly

Type of Research (con’t)

Randomized Control Trial DesignR O1 X1 O2 X2 O3

R O1 O2 O3

R = Randomized SamplesO1-3 = ObservationsX1-2 = Tai Chi intervention

Type of Research (con’t)

AdvantagesGood for assessing change during and after

interventionMain threats are controlled (testing, maturation

etc.)Disadvantages

Attrition ratesDiffusion of intervention (ie control group increases

activity)Resentment for no intervention

Research Methods

Individuals responded to newspaper ads and flyers at senior centers

Inclusion criteria 65 years of age or olderLow active according to PASE (Physical Activity

Scale for the Elderly)– no involvement in regular exercise program within the last month

Healthy – exercise will not have negative physical effects

Willingness to be randomly assigned

Research Methods (con’t)

98 individuals 65-96 years old were chosen

Assigned to either a Tai Chi practice group or a waiting list

Assessed demographic characteristics: age, gender, education, income & ethnicity

6 month trial

Research Methods (con’t)Intervention group

Yang Style Tai Chi

60 min. practice sessions 2x/week for 6 months

15 min. warm up, 15 min cool down included in practice session

Control GroupMaintained

routine activitiesCould not join

new exercise programs

Promised a 4 week Tai Chi program at the end

What is Yang Style Tai Chi?Yang Style Tai Chi is a slow moving form that affects balance

postural alignment & concentration

Research Methods (con’t):Outcome Measures

Barrier scale self-efficacy5 items to assess

perception of ability to perform Tai Chi regularly in the face of barriers (ie. Pain, boredom etc.)

0-100 confidence scale (0=very little confidence, 100=complete confidence)

Performance scale self-efficacy3 item task-specific,

time-basedDegree of confidence

in ability to successfully perform a series of slow, rhythmically changing body position movements

0-100 confidence scale

Outcome Measures con’t

Class AttendanceExercise behavior was assessed by

attendance taken by instructorFrequency of Measurements

Baseline measures - prior to study2nd measures – week 123rd measures – week 24

(intervention group responded in class within 1 week, control group responded by mail)

Main Findings

Tai Chi exercise program can significantly enhance perceptions of task-specific personal efficacy in older adults

The Tai Chi group developed higher perceptions of efficacy, adhered better to the exercise program and spent more time engaged in exercise (therefore increased exercise participation)

Main Findings (con’t)

Intervention (Tai Chi) groupBoth types of efficacy increase over time

Initial boost from baseline to 2nd observationMaintenance from 2nd to 3rd observation

Class attendance was significantly predicted by the changes in the 2 types of efficacy

Control groupBoth types of efficacy decreased over time

Main Findings (con’t)

Change in barrier efficacy between Tai Chi and Control

Change in performance efficacy between Tai Chi and Control

Brief Critique

All subjects were volunteers – this could make generalizability difficult

Gender was recorded but not specified in results – potential influence of a moderator variable

Monitoring attendance issues – no parameters set aside for absenteeism - assumption that absenteeism is due to self-efficacy

All self-efficacy measures are self-reported therefore subject to social desirability biases

Brief Critique (con’t)

Physical activity in control group was not monitored throughout the studyNo data comparing the decrease in self-efficacy to a

decrease in activityMotivation issue – feel obligated to attend

because are in the studyWould participants attend these classes if not in the

study? (long term adherence)Validity of claim: intervention should be

compared to other organized activities/classes

Brief Critique (con’t)

Ethical issues: Control group was only offered a 4 week Tai Chi class after the study, whereas intervention group got 6 months

Self-efficacy measures are based on performance of Tai Chi not general daily activity (not applicable to control group)

Warm up and Cool down not specifiedSample size decreased due to attrition which

could impact generalizability

Future Research Suggestions

Compare Tai Chi results to more Traditional forms of exercise (ie. Strength training, walking, stretching, etc.).

Compare positive effects of Tai Chi in other age groups.

Look at adherence over longer periods of time or post-intervention (months, years later)

Future Research Suggestions (con’t)

Impact of Tai Chi on health & related aging problems as compared to other activities/interventions.

Examine impact of Tai Chi on adherence to/participation in activities of daily living

Other questions that can be addressed with True

Experimental Research

Can be used for any study involving an intervention (ie. Drug, exercise, acupuncture, rehabilitation therapy, any lifestyle factor etc.) on a sample of a specific population

THE END