Developing a Text-Message Enhanced Physical Activity Intervention for Latino Men
Phase: NA
Conditions: Inactivity
Sponsor: University of California, San Diego

 
 
Project Title:  Developing a Text-Message Enhanced Physical Activity Intervention for 
Latino Men 
 
NCT Number: NCT02512419 
 
Contents: 
 
1) Research Protocol:  
Please note, that the date on the research protocol is the latest version of that form that 
the UCSD IRB has. The date is generic to the template version, not specific to the 
submission or approval date. That protocol was approved on the most recent date of 
7/27/18.  
2) UCSD IRB Approval 
Most recent approval date: 7/27/18 
3) Statistical Analysis Plan 

 
 
UCSD Human Research Protections Program 
New Biomedical Application 
RESEARCH PLAN 
Instructions for completing the Research Plan are available on the HRPP website. 
The headings on this set of instructions correspond to the headings of the Research Plan. 
General Instructions: Enter a response for all topic headings.  
Enter “Not Applicable” rather than leaving an item blank if the item does not apply to this project. 
Version date: 9/30/2013 
1. 
PROJECT TITLE 
Developing a Text Message Enhanced Physical Activity Intervention for Latino Men (Activo) 
2. 
PRINCIPAL INVESTIGATOR  
Bess Marcus, PhD 
3. 
FACILITIES 
Altman Clinical Translational Research Institute (ACTRI), East Campus Office Building (ECOB), Stein Clinical 
Research Building, Vista Community Clinic, South County Career Center, or off-site UCSD Facility. 
4. 
ESTIMATED DURATION OF THE STUDY 
2 Years 
5. 
LAY LANGUAGE SUMMARY OR SYNOPSIS (no more than one paragraph) 
The aim of this study is to build upon our tailored print intervention by developing new text-delivered 
intervention materials to complement our print-based physical activity (PA) intervention. In Phase 1 we will 
conduct 6 focus groups with Mexican and Mexican American (MA) men to determine content, frequency, and 
types of text messages desired, and to identify cultural themes to incorporate into existing and new materials. 
Themes from the focus groups and sample text messages will be presented to a confirmatory focus group 
panel. Phase 2 will be a 6-month pilot randomized controlled trial with MA men (N=60) to test the text-
enhanced, Spanish language, individually tailored PA intervention vs. publicly available, Spanish language 
health education materials, including information on PA, diet, and stress management. This will be followed by 
post-intervention qualitative interviews to solicit suggestions for improvements to help further refine the 
program. The proposed pilot will support a future R01 to establish the efficacy of this multi-media, multi-level 
PA intervention for MA men. 
6. 
SPECIFIC AIMS 
 Primary Aims:  
1. Aim 1: To conduct the formative research necessary to develop new text message-based materials based 
on Social Cognitive Theory (SCT) constructs and a resulting text messaging intervention program to 
complement and enhance our current print-based PA intervention for MA men.  
2. Aim 2: To determine the feasibility, acceptability, and preliminary efficacy of the text message enhanced PA 
intervention for MA men. We hypothesize that those randomized to the text message enhanced PA 
intervention condition will report greater increases in weekly minutes of PA after six months than those 
randomized to the health education control condition.  
7. 
BACKGROUND AND SIGNIFICANCE 
Back and Significance 
The proposed research addresses serious public health concerns (inactivity, health disparities) in a large, 
rapidly growing population of Mexican and Mexican American (MA) men who are markedly less physically 
active than men of other ethnicities and suffer from higher prevalence of conditions related to sedentary 
lifestyle. While this population is clearly in need of physical activity (PA) interventions, to date none have 
specifically targeted MA men. In fact, the majority of PA interventions for Latinos have exclusively included 
women and/or are designed around female preferences. The proposed study will address the needs and 
barriers to PA in MA men by developing text message-delivered intervention materials based on Social 
Cognitive Theory (SCT) to complement an individually tailored, theory-based print material PA intervention for 
Spanish speaking MA men. Text messaging could be a particularly effective and appealing channel for 
increasing PA in this target population as it allows for participant interaction, real-time accountability, and 
immediate feedback, features which MA men in the demonstration trial of our print intervention specifically 
requested. Text-based interventions have been shown to improve a number of health behaviors, including PA. 
A recent review of texting interventions found that they were generally well received and effective in reducing 
inactivity, weight, and waist circumference, and a meta-analysis found a moderate effect size (g = 0.54) for 
using mobile devices to increase PA. However, few of these trials targeted underserved populations, and none 
specifically targeted Latinos. Cell phone ownership is high in Latino adults (86% vs. 84% in non-Latino 

 
 
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Whites), and Latinos are actually the most likely to use mobile phones for text messaging, with 85% reporting 
regularly sending and receiving texts (compared to 79% of Whites). Thus this is a familiar, convenient channel 
for delivering new intervention materials. Additionally, as Latinos also face environmental barriers to PA, in the 
current proposal we will enhance the individually tailored psychosocial print-based materials by developing 
materials targeting barriers in home and work environments. This multi-media, multi-level approach has 
potential for broad reach at relatively low cost, which could help reduce health disparities. 
 
Preliminary Studies/Previous Work 
Study Team: Dr. Marcus (PI) and colleagues have spent the past 25 years developing and testing empirically 
supported individually tailored PA interventions (e.g., R011HL64342, R01HL69866). This intervention was 
culturally and linguistically adapted for Latina women and successfully implemented in this underserved 
population in two studies (R21NR009864, R01NR011295). We have extensive experience in designing, 
implementing and evaluating theory-based, culturally-adapted PA interventions for Latinos (Drs. Marcus, 
Pekmezi, Larsen, Hartman, Nodora), using text messaging for promoting behavior change (Dr. Patrick), 
environmental influences on PA (Dr. Sallis), recruitment and retention of Latinos (Drs. Marcus, Rojas, Pekmezi, 
Larsen, Nodora), and statistics (Dr. Dunsiger). See Table 1. 
 
Table 1. Past Studies of Research Team that Directly Relate to the Current Proposal 
PI/ Funding: Description 
Results 
Culturally and linguistically adapting an empirically supported theory-based print PA intervention for Latinas 
Marcus (PI) R21NR009864: 1) 25 cognitive 
interviews to clarify content of translated/ back 
translated materials and measures; 2) 6 focus 
groups on PA barriers for Spanish speaking 
Latinas (N=34); 3) Pilot RCT of adapted 
intervention (N = 93 Latinas). 
Themes from participant feedback were incorporated into the intervention 
including: 1) Literacy level; 2) Daily stressors/Negative Mood; 3) Lack of Time; 4) 
Neighborhood Safety; 5) Lack of Motivation; 6) Partner Support.  
RCT findings: Mean increase of 130.71 min/week (sd=242.52) from baseline to six 
months amongst intervention participants compared to 84.92 min/week 
(sd=118.26) amongst controls.  
Marcus (PI) R01NR011295: Ongoing RCT to 
test the efficacy of the culturally/ linguistically 
adapted, individually tailored print intervention 
for Latinas (N=268). 
82% speak only Spanish or more Spanish than English at home. Six month 
findings indicate significantly greater increases in at least moderate intensity PA 
from baseline to 6 months (M=71.66 min/week, sd=89.92) for Intervention vs. 
Control (M=29.58 min/week, sd=84.37), p<.01.  
Preliminary efforts to identify and address the specific PA intervention needs and preferences of MA men  
Marcus (PI) UCSD Intramural funds: 
Individual interviews with Spanish speaking 
MA men (N=10) about PA intervention needs 
and preferences.  
Culturally-specific themes included 1) Importance of family, 2) Gender roles 
(“Machismo”), 3) Demanding and irregular work schedules, 4) Preference for 
team sports, 5) Cultural norms, 6) Preference for Spanish language, and 7) A need 
for accountability.15 Intervention was adapted in response to feedback. See 
Appendix H for full details of cultural modifications.  
Marcus (PI) UCSD Intramural funds: Single 
arm demonstration trial of the resulting, 
tailored theory-based print PA intervention for 
Spanish-speaking MA men (N=10) followed 
by individual interviews. 
100% retention and significant increase in PA at 3 months (mean increase 
=124.20 min/week, sd=154.86, p=0.032).  Participants indicated high satisfaction 
but that participation and motivation could be enhanced by: 1) greater 
accountability, 2) more contact with staff, 3) shorter and more frequent tips, and 
4) real-time updates on PA opportunities. Participants also expressed interest in 
receiving PA text messages. 
Text Message Intervention Studies  
Patrick (PI) R21CA115615: Focus groups to 
identify quantity/timing of text messages for 
weight loss intervention in overweight/ obese 
men & women. RCT to test resulting text 
message intervention (N=65).   
At 4 months, intervention group lost more weight than controls (4.34 pounds 
more; p=0.02). Adherence to responding to text messages was high. Overall 
satisfaction with the intervention was also high, with 96% of participants stating 
that they would recommend the intervention to friends and family. 
Patrick (PI) R01CA138730: Ongoing follow-up 
to R21 using formative research to develop 
Spanish-language intervention and then conduct 
a 12-month RCT (N=298). 
Focus group feedback was used to develop culturally appropriate text messages 
for Latinos. Overweight/obese English (n=236) and Spanish (n=62) speakers were 
randomized to a 3 arm weight loss intervention: text message only, text message 
plus counseling, or usual care.   
8. 
PROGRESS REPORT 
N/A 
 

 
 
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9. 
RESEARCH DESIGN AND METHODS 
Overall Design: The present study will be conducted in two phases. In Phase 1 we will conduct formative 
research to further enhance our empirically supported, theory-based, personally tailored PA print materials by 
1) developing interactive and tailored text message PA intervention components to meet the needs and 
preferences of Spanish-speaking MA men, and 2) incorporating culturally specific themes and creating 
materials tailored to neighborhood environments. In Phase 2, we will conduct a pilot RCT to test the text-
enhanced individually tailored PA intervention for MA men vs. a health education control arm.  
 
Phase 1: Formative Research: Our goal with the formative research phase of this study is to inform the 
development of a text message enhancement to address the concerns of MA men identified in our pilot work, 
and to incorporate culturally specific themes into text and print intervention materials. Specifically, we plan to 
build upon our existing theory-based individually tailored intervention by developing interactive and tailored text 
message intervention materials that address the feedback of the MA men by increasing accountability, 
providing more frequent contacts, allowing for interactivity between participants, and improving motivation. 
Focus groups will also be used to determine the most useful features of tailored environmental reports.  
 
We will conduct 6 focus groups with 6 to 8 MA men per group or one-on-one meetings with a staff member if 
needed.   Eligibility includes: a) self-identified as MA; b) able to speak and read Spanish; c) currently engaging 
in less than 60 minutes of activity per week; and d) no health-related contraindications for becoming more 
active including history of coronary heart disease, diabetes, stroke, osteoarthritis, or orthopedic problems (see 
Phase 2 for further detail). The focus groups will be lead by a bilingual, bicultural researcher; each focus group 
is expected to last 1 hour. 
 
We will use data from the focus groups to develop the text messaging intervention materials and program and 
identify cultural themes to incorporate into print and text materials. After the text message enhancement has 
been developed we will invite a random sub-sample of the men who participated in the focus group to attend a 
confirmatory panel (n=6). This provides an opportunity to confirm intervention preferences and correct any 
misunderstandings, as well as allow the participants to further elaborate upon initial focus group responses. 
Sample text messages will be provided so participants can approve/disapprove any changes and new content. 
 
Qualitative Data Analysis: For qualitative data analysis, all focus groups will be audio taped and translated 
into English. A content analysis will be conducted to generate themes related to PA intervention needs and 
preferences of the MA men that will aid in refining the text message enhancement. Bicultural staff members 
and other investigators, will analyze the transcripts in a two-step process. In the first step, two investigators will 
read through the transcripts to look for themes that are consistent with prior literature and theory (a deductive 
process) and gender- and cultural-specific themes that are revealed by the participants themselves to be 
common across MA men (an inductive process) to develop a set of codes/labels and definitions for the 
themes. In the second step, two investigators will use this set of codes to label each statement within the 
transcripts. Transcript coding will be compared between investigators and inconsistencies will be discussed 
among all investigators until consensus agreement of the appropriate code is achieved. All text and coding will 
be done with the use of NVivo qualitative software. This content analysis will be used to inform the 
development of the text-enhanced PA intervention for MA men. 
 
Phase 2: Pilot Randomized Controlled Trial: We will randomize 60 MA men into a 6-month pilot trial of the 
resulting text-enhanced PA intervention for MA men vs. a health education control. The procedures for 
recruitment, pre-trial screening, and monitoring derive from our team’s experiences conducting similar trials (e. 
g., R21NR009864, R01NR011295, R01HL64342). See Figure 1. Although it is preferred that participants 
attend all visits in person, they will be informed during the telephone screening process that modified versions 
of study visit can be offered via phone in the event that they are not able to travel to the study site.  

 
 
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Telephone Screening:  To reduce the likelihood of adverse events, participants will be phone screened for 
factors that may increase risk of injury. Potential participants with medical or psychological problems that could 
make adherence with the study protocol difficult or dangerous will not be included. Exclusions include history 
of coronary heart disease, history of myocardial infarction, symptoms of angina, type 1 diabetes, uncontrolled 
hypertension, stroke, osteoarthritis, osteoporosis, orthopedic problems that would limit activity during the 
following six months, currently engaging in more than 90 minutes of activity per week or any other serious 
medical condition that would make physical activity unsafe. Other exclusion criteria will include hospitalization 
due to a psychiatric disorder in the past 3 years, BMI above 45 kg/m2 and/or taking medication that may impair 
physical activity tolerance or performance (e.g., beta blockers). After screening is completed, eligible and 
interested participants must agree to be randomly assigned to one of the intervention conditions and provide 
written consent to participate in the research protocol. In addition, participants will be informed that in the event 
that they cannot attend an in-person visit at any of our study sites, they will have the option to complete the 
visit via phone. All in-person visits (including those occurring at our off-site UCSD facilities) will be conducted 
by our trained study staff. Descriptions of both in-person visits and phone visits are provided below. 
 
In-Person Visits: 
 
Orientation/Measurement Visit: Following telephone screening for eligibility, interested individuals will be 
asked to attend an in-person orientation session in which a bilingual/bicultural research staff member will 
provide information about the study. During this session, all questions regarding participation in the study 
will be answered. Participants will then be asked to read and sign a consent form approved by the 
university’s institutional review board. Participants will also complete anthropometric measures and an initial 
battery of psychosocial measures during this visit. Self-reported height and weight will be accepted. At the 
end of this visit, the participant will be given and instructed on how to use an accelerometer during the next 
seven days. 
 
Baseline/Randomization Visit: One week after the orientations/measurement visit, the participant will return 
the accelerometer, complete a 10-minute treadmill walk at moderate intensity (3-4 miles per hour) to 
demonstrate understanding of moderate intensity activity, and complete the 7-Day Physical Activity Recall 
(PAR). At that time, participants will be randomly assigned to one of two conditions: 1) a text-message 
enhanced, Spanish language, individually tailored, print-based physical activity intervention; or 2) a Spanish 
language print-based health education control.  
 
Months 1-6: After randomization, participants will fill out monthly mailed questionnaires for 6 months. 
Individuals randomized to the physical activity arm will receive individually tailored reports generated by a 
computer expert system along with messages appropriate for their stage of motivational readiness for 
physical activity adoption immediately following completion of the questionnaires. Those randomized to the 
health education control condition will also receive monthly mailed questionnaires and materials on health 

 
 
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topics related to cardiovascular disease, such as nutrition, physical activity, and stress management 
information. Participants will also be receiving text messages related to exercise or health and wellness 
depending on their group assignment. The schedule and amount of contact will be the same across 
conditions. 
 
6 Month Assessment: All participants will be asked to attend an in-person visit at 6 months to recomplete all 
measures completed during the initial measurement visit and baseline visit.  
 
Telephone Visit: 
In the event that participants cannot attend any of our in-person visits, they will have the option to complete the 
visit via telephone. Details of each of these visits are provided below.  
 
Orientation/Measurement Visit:  
Following telephone screening for eligibility, participants will be asked to schedule a phone call visit in which a 
bilingual/bicultural research staff member will provide information about the study and review the consent 
documents. Details of the informed consent process via phone are addressed in section 12. Also following the 
telephone screening, participants will be mailed the UCSD IRB approved informed consent documents along 
with a battery of psychosocial questionnaires. Once the participants have received the mailings, a phone call 
with a bilingual/bicultural research staff member will occur where the participants will be provided with 
information about the study and the staff will review the informed consent documents.   
 
If the participant decides to participate in the program, they will then be asked to sign the consent documents 
and mail back in a pre-paid envelope that we will provide. Once we have received the signed informed 
consent documents, a staff member will inform the participants that they can now complete the mailed 
questionnaires and return them to us. The informed consent documents and questionnaires will be sent in 
separate envelopes when being mailed, although they will be sent at the same time-point. It will be clearly 
stated on the questionnaire packet that they are NOT to complete the battery of questionnaires until we have 
received their signed informed consent document in the mail.  
 
Once we have received the signed informed consent documents and completed psychosocial measures, 
staff will then schedule another call with the participant to provide additional information regarding the 
randomization visit as well as instructions on how to use an accelerometer that will be mailed to them. During 
this phone visit, the following components cannot be conducted: STOHFLA measure and anthropometric 
measures including height, weight, blood pressure, and bioelectrical impedance analysis. Self-reported height 
and weight will be collected as an alternative. 
 
Baseline/Randomization Visit: Project staff will mail the accelerometer as well as the materials for the 
randomization visit. Upon receiving the accelerometer, participants will be asked to wear this device for 7 days 
and return to us in a provided pre-paid envelope. Once our staff has received this device, they will schedule 
the phone randomization visit. During the randomization visit participants will complete the 7-Day Physical 
Activity Recall (PAR) and be randomly assigned to one of two conditions: 1) a text-message enhanced, 
Spanish language, individually tailored, print-based physical activity intervention; or 2) a Spanish language 
print-based health education control. During this phone visit the 10-minute treadmill walk cannot be 
conducted. 
 
6 Month Assessment: Similar to the baseline/randomization visit, in the event that participants cannot attend 
their in-person visit, they will have the option to complete the visit via phone. During this phone visit, the 
following components cannot be conducted: the 10-minute treadmill walk and anthropometric measures (as 
stated above). Self-reported height and weight will again be collected as an alternative. 
 
Treatment Conditions  
Text-Enhanced Physical Activity Intervention Arm: The Spanish-language PA intervention is based on 
SCT and Transtheoretical Model (TTM), and emphasizes behavioral strategies for increasing activity levels 
(i.e., goal-setting, self-monitoring, problem-solving barriers, increasing social support, rewarding oneself for 

 
 
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meeting PA goals). At baseline participants will receive a pedometer, set a detailed PA goal, problem-solve 
around barriers to achieving their PA goal, and receive recommendations for walking/jogging routes, parks 
with athletic equipment and playgrounds, and other places to be active surrounding their work or home. They 
will receive regular mailings: weekly in month 1, bi-weekly in months 2 and 3, and monthly in months 4 to 6. 
Mailings consist of: 1) Manual matched to the participant’s current level of motivational readiness to change, 
based on TTM; 2) Individually tailored computerized expert system feedback reports based on the participant’s 
answers to monthly questionnaires (see Measures) that compares participants to their prior responses 
(progress feedback) and to individuals who are physically active (normative feedback) on: self-efficacy for PA 
and cognitive and behavioral strategies associated with PA behavior change (processes of change); 3) PA tip 
sheets addressing PA barriers. These print materials have been modified for MA men based on cultural 
themes identified during our formative work and trial (e.g. focus on family, team sports, “Machismo,” etc.).  
Participants will also receive the text message intervention that will be developed as part of Phase 1 of this 
proposal. Based on our previous formative research, reviews of the literature, and theories of behavior change 
we anticipate using interactive, tailored, and culturally adapted text messages to: 1) increase accountability, 2) 
help navigate their environment, 3) increase competition, 4) increase motivation, 5) inform about local events, 
6) focus on the family, 7) provide social support, and 8) increase the study’s connectivity with participants. See 
Table 3 for proposed text messages, examples of text messages, and how they fit with SCT. Participants will 
receive $5 per month to defray the costs of the text messages. 
 
 
 
Health Education Control arm: The health education control arm will receive the publicly available NHBLI 
Spanish-language booklets on heart-healthy behaviors for Latinos, which include information on PA, diet, and 
stress management. Similar to intervention participants, control participants will receive tip sheets on related 
health topics. The health education content was vetted in our individual interviews with MA men who 
expressed a strong interest in receiving and reading these materials. Mailed contacts for the control group will 
be on the same schedule as the mailed contacts for the intervention condition (weekly month 1, bi-weekly 
months 2 and 3, and monthly months 4 to 6). Participants in the health education control arm will also 
complete monthly questionnaires relevant to the topics of their materials. 
 
List of Measures 
7-Day PAR Interview provides an estimate of total weekly minutes of PA.  
Demographics measure will assess age, education, income, race, and marital status, and acculturation scale. 
Stages of Change for Physical Activity (SCPA) measure has successfully been used to stage-match 
treatment. 
Processes of Change for Physical Activity (POC) measure contains 10 subscales that address a variety of 

 
 
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cognitive/behavioral processes related to PA behavior change.  
Self-Efficacy For Physical Activity (SE) measures self-efficacy to become physically active across diverse 
contexts.  
Neighborhood Environment Walkability Scale, Abbreviated (NEWS-A) assesses various aspects of the 
built environment related to walking, neighborhood aesthetics, and traffic.  
ActiGraph. For the week prior to each 7-Day PAR assessment, all participants will wear an Actigraph, which 
measures movement and intensity of activity.  
Health-O-meter medical scale will be used to measure body weight and height. 
Short Test of Functional Health Literacy in Adults (STOHFLA) tests literacy for English and Spanish 
speaking patients in healthcare settings.  
Consumer Satisfaction Measure was used by our research team in past trials and adapted for the current 
study to assess feasibility/acceptability of this the text-enhanced PA intervention.  
Wellness Questionnaire assesses knowledge about health topics presented in the control materials.  
10. 
HUMAN SUBJECTS 
For Phase 1 we will recruit 48 participants and for Phase 2 we will recruit 60 participants. Participants in both 
phases will be sedentary (i.e., participating in moderate or vigorous physical activity two or less times per week 
for 30 minutes each time or less) men between the ages of 18-65 who self-identify as Mexican or Mexican-
American. Participants in Phase 1 will participate in focus groups to guide development of the text-message 
components. Participants in Phase 2 will participate in a randomized clinical trial of a text-enhanced culturally 
and linguistically adapted, Spanish language, mail-delivered print intervention to promote physical activity.  
 
Phase 1: Interested men will be telephone screened for eligibility. Interested and eligible men will be invited to 
attend a focus group to discuss preferences surrounding text-messages to increase physical activity. A 
randomly selected sub-sample of participants will be asked to return for a confirmatory panel. All participants 
will provide written consent to participate.  
 
Phase 2: We will recruit men to enroll in a randomized controlled trial of the newly developed text-enhanced 
physical activity intervention compared to a publicly available, Spanish-language health education control, 
including PA, diet, and stress management information. 
 
Eligibility Requirements for Phase 1 and 2: We will recruit men between the ages of 18-65 who self-identify 
as Latino and own a cell phone capable of sending and receiving text messages.  
 
Exclusion criteria for Phase 1 and 2: To reduce the likelihood of injury participants will be screened with the 
Physical Activity Readiness Questionnaire. Potential participants with medical or psychological problems that 
could make adherence with the study protocol difficult or dangerous will not be included. Exclusions include 
history of coronary heart disease, history of myocardial infarction, currently engaging in more than 90 minutes 
of activity per week symptoms of angina, type I diabetes, uncontrolled hypertension, stroke, osteoarthritis, 
osteoporosis, orthopedic problems that would limit activity during the following six months, or any other serious 
medical condition that would make physical activity unsafe. Other exclusion criteria will include hospitalization 
due to a psychiatric disorder in the past 3 years, BMI above 45 kg/m, and/or taking medication that may impair 
physical activity tolerance or performance (e.g., beta blockers). The study physician will advise on medical 
questions that arise when screening for eligibility.  
11. 
RECRUITMENT AND PROCEDURES PREPARATORY TO RESEARCH 
Recruitment will follow a community-based, participatory model in that key community-based organizations 
and their leadership will be consulted and involved in recruitment. As in previous studies, we will employ 
multiple recruitment strategies. These strategies include: 
1) We will recruit through local physicians (through the UCSD Department of Family Medicine) whose 
patient populations are largely Mexican and Mexican-American. Some of these physicians are Latino 
and bilingual. These physicians will provide potentially eligible participants (or their family members) 
with information on the study. 
2) Targeting both directly to Mexican and Mexican American men who may be eligible, and to Latinas 
who could refer eligible male family members.  
3) Posting and distributing flyers and advertisements in public areas, community organizations, and 

 
 
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community events with high traffic of Mexican and Mexican American men.  
4) Posting and distributing flyers and advertisements on websites and on email list serves. 
5) Going out into the community, such as by attending community events, health fairs, talk shows etc. to 
actively recruit and inform participants about the study. This will include doing presentations and 
collecting names and contact info of interested potential participants. 
6) We will list our study on UCSD’s CTRI ResearchMatch database and will use this resources to contact 
potentially interested participants.  
7) Paid advertisements through print ads, web-based ads, radio, TV, and other venues. 
8) We will be creating a Facebook business page exclusively for the advertisement of the Activo Study 
according to the IRB study guidelines.  
 
Recruitment efforts will be not be limited to the Greater San Diego area, and will expand across the United 
States where applicable (websites, radio, TV, etc.) 
12. 
INFORMED CONSENT 
Upon seeing study recruitment flyers and advertisements, interested individuals will call the study line to learn 
more about the study. After hearing a brief description of the study, participants will decide if they would like to 
participate in a brief telephone phone-screening interview to assess initial eligibility. Screening interviews are 
audiotaped and scripted. The screening interview script has a checkbox for the research staff to document 
receiving permission from the prospective participant to proceed with the screening interview. Furthermore, 
participants will be reminded throughout the phone-screening interview that participation is voluntary and can 
be ended at any point, thus minimizing the possibility of coercion or undue influence. In addition, this 
documentation can be verified through audiotapes of the screening interviews. A waiver of documented 
consent is requested for this oral screening process based on meeting the following UCSD IRB criteria: 
 
a) that the only record linking the subject and the research would be the consent document and the  
    principal risk would be potential harm resulting from a breach of confidentiality 
 
b) that the research presents no more than minimal risk of harm to subjects and involves no  
    procedures for which written consent is normally required outside of the research context. 
 
 
Following telephone screening, interested individuals will be asked to attend an in-person (group or individual) 
or phone orientation session. Trained bilingual/bicultural research staff with sufficient knowledge of the study 
to answer any questions regarding the study and appropriate IRB/CITI training will provide information about 
the study. During the session, all questions regarding participation in the study will be answered. All potential 
participants will be fully informed of the study’s procedures and requirements that are also thoroughly 
described in the informed consent. Thus, interested individuals will have sufficient time to read and consider 
whether to participate. Furthermore, participants will be reminded throughout the orientation that participation 
is voluntary and can be ended at any point, thus minimizing the possibility of coercion or undue influence. 
Methods of documenting consent/assent/permission/authorization to participate in the actual study will include 
having the prospective participant and research staff sign, initial, and date the consent forms. The research 
staff will obtain consent/assent/permission/authorization in English or Spanish, whichever language is 
preferred by the prospective participant. If the individual prefers, a copy of the consent form may be mailed 
prior to the face-to-face meeting to provide more time to consider the study. However, the final consent form 
must be signed in-person prior to participation in the focus group or individual meeting. All participants will also 
receive a signed copy of the consent form and a copy of the Experimental Subject’s Bill of Rights. Both 
Spanish and English versions of these documents will be provided. 
 
For phone sessions, staff will discuss with the participant the steps to maintain confidentiality during these 
visits. For example, it will be required for participants to complete the phone sessions in a private place with no 
one else around (this protects the privacy of the subject as well as the inadvertent transmission of voice of a 
non-consented person). Regarding audio recording of the in-person and telephone sessions, participants 
voluntarily sign an audio recording release consent form approved by the university’s institutional review 

 
 
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board. All of the procedures above regarding the consenting process remain the same via phone. Note: 
although telephone is an option to review the consent and answer any questions regarding the consent during 
the orientation session, participants will not actually be consented via telephone. Participants will still need to 
sign and mail back their informed consent to participate in the study. 
 
The information being communicated to the participant during the consent/assent/permission process will not 
include exculpatory language through which the participant is made to waive or appear to waive any of the 
participant’s legal rights or release or appear to release the Research, Sponsor, the University or its agents 
from liability for negligence. 
13. ALTERNATIVES TO STUDY PARTICIPATION 
The alternative to study participation is to not participate. 
14. 
POTENTIAL RISKS 
Complications associated with moderate intensity exercise training (orthopedic injury) 
Likelihood:  Rare 
Minimization:  Participants will be screened for orthopedic problems, particularly gait disturbances, before 
enrolling, and they will be monitored throughout the 6-month intervention. Specifically, participants will be 
instructed to alert us of any orthopedic injury sustained as soon as possible.  This will trigger a call from our 
projector director and/or study physician. If an injury has occurred, we will request that the participant follow-
up with his primary care provider before continuing in the study. If participants are unable to complete the 
treadmill walk at the baseline visit due to physical/medical limitations, they will be deemed ineligible.  
 
Loss of Confidentiality 
Likelihood: Rare 
Minimization: Confidentiality will be maintained by numerically coding all data, disguising identifying 
information, and keeping all data in locked file drawers. All information obtained from participants will be 
accessible only to research staff. All texting between participants will be relayed through the study server, so 
individual telephone numbers will not be shared. Participants will have the ability to opt out of receiving group 
text messages. 
15. RISK MANAGEMENT PROCEDURES AND ADEQUACY OF RESOURCES 
Potential complications associated with moderate intensity exercise training at levels recommended by the 
CDC/ACSM are rare. However, subjects may find exercising uncomfortable and may experience sprains, other 
soft tissue injuries, or bone injuries. At the start of the study all participants will be given an instruction sheet 
that details what to do for common exercise-related injuries, as well as the Project Director’s contact 
information. In addition, we will require each participant to complete a monthly Health Expense Form. Since 
participants are enrolled on rolling basis, these forms will be reviewed by the project coordinator within 24 
hours of being received.  Any injuries that may have occurred because of, or in relation to, exercise training 
that are noted on the Health Expense Form will be relayed by monitoring team within 24 hours. Although the 
likelihood is low, our research staff has well-established procedures for monitoring and responding to adverse 
events resulting from moderate intensity physical activity, as well as loss of confidentiality.   
 
Participants will be asked to notify us immediately (no later than 24 hours) if they sustain an injury. Procedures 
and protocols for reporting and managing adverse events, are addressed in the NINR approved Data Safety 
Monitoring Plan, previously submitted to the IRB. 
16. PRIVACY AND CONFIDENTIALITY CONSIDERATIONS INCLUDING DATA ACCESS AND MANAGEMENT 
Informed Consent: There is a potential risk of participating in a group orientation session.  During the 
consenting process other participants will be in the room, which could lead to a loss of your confidentiality.  
While we ask all participants to protect and respect other people’s confidentiality, we cannot guarantee that all 
participants will abide by this request.  Although information about the study and the informed consent process 
will be conducted in a group setting, the research staff will also be available to discuss any questions or 
concerns privately. Participants will also have the option of reading, discussing and signing the consent forms 
in a private area if they prefer. In addition, we will take all necessary and possible precautions to avoid loss of 
confidentiality during group orientation sessions, including only referring to individuals by their first names, with 
no mention of last names.  
 

 
 
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Procedure for Collection of Data: Research participants will complete baseline questionnaires, as dictated 
by the study protocol. All data collected are considered part of the subject's confidential record and will be 
placed in a locked file cabinet within 24 hours of acquisition as designated by the study's Data Manager. All 
data will remain confidential.  A file that associates the subject name with that subject's study identification 
number will be maintained. This file will remain locked in a file cabinet and will not be stored with the actual 
study data. 
 
Accelerometers: The data collected from the accelerometers will be used as primary data. Data 
downloaded from the accelerometers will be incorporated into the database that contains all other collected 
study data. Backup copies of the original downloaded files will be maintained on the university network. 
 
Storage of Collected Data: All paper data will be stored in a locked file cabinet. Data will only be removed 
when coded, entered, or audited. The study's Data Manager will be responsible for the secure storage of all 
project questionnaire data. Collected data will be de-identified by a data manager to ensure that all personal 
identifiable information cannot be connected to the data provided by participants through the surveys. All de- 
identified data will then be backed up and stored onto a secure, password protected, shared network at 
UCSD. The shared network will require a login and password in order to gain access to the data. Only the 
data manager will have access to the data in its raw state. All other authorized staff (e.g., research assistants, 
and Project Director) will view de-identified data via forms and reports created by the data manager. 
 
Data Entry Requirements: All data will be coded by a research assistant prior to entry. Any ambiguity in 
responses to questions will be brought to the attention of the Data Manager for clarification. If the Data 
Manager is unsure how to code the response, the matter will be brought to the attention of the study’s 
Principal Investigator. The Data Manager will maintain a log so that future occurrences of problems will be 
handled in the same manner. 
 
The data entry system will require a login identification and password in order to gain access to the data. 
Where appropriate, validation and range rules will be applied to the actual entry fields. Only the Data 
Manager will be able to view the data in its raw state. All other authorized staff (Principal Investigator, 
research assistants, and Project Director) will view data via forms and reports created by the Data Manager. 
 
Audit/Verification of Entered Data: Primary outcome data will be subject to 100% cross-referencing with 
the original paper copy. This audit must have an error rate less than 1%. If the verification fails the audit, all 
data will be re-entered, the original computer files discarded, and the newly re-entered data audited. This 
process will continue until the audit no longer exceeds the maximum allowable error rate. All audits will be 
supervised and documented by the study’s Data Manager. 
 
All other entered information will be subject to a 20% sample that will be cross-referenced with the original 
paper copy. This audit must have an error rate of less than 1%. If the sample fails the audit, all data will be 
verified against the paper originals. If the error rate of the complete audit is greater than 1% then all data will 
be re-entered, the original computer files discarded, and the newly re-entered data audited. This process will 
continue until the audit no longer exceeds the maximum allowable error rate. At the discretion of the Principal 
Investigator, the full audit may be omitted in favor of a complete re-entry of the original paper data. All audits 
will be supervised and documented by the study’s Data Manager. 
 
Final Storage of Collected Data: Once data have been coded, entered, and passed audit verification, 
paper copies of data will be housed at a facility that specializes in the storage of medical/research 
information. This housing facility will not be at UCSD. This is a location that specializes in housing secure 
research files offsite. A commonly used company that other UCSD research groups have used for this 
purpose, is the Iron Mountain Storage facility. These data will only be sent to this location once it has been 
coded, entered, passed audit verification, and is no longer needed for the duration of the study. Only the 
subject's study identification number will be present on the forms. All electronic data will be backed up and 
stored onto a secure, password protected shared network. Any indication of the subject's name will be 
removed from the questionnaires prior to its archiving. The destruction date of these files will be at least 7 

 
 
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years from the termination of the study and will be authorized by the Principal Investigator of the research 
study. 
 
Access to Cleaned Computer Data: Once the study is complete, and all data have been collected, entered 
and passed the audit process, the Data Manager will make the data available to the Principal Investigator and 
her designates. Only the Principal Investigator can give permission for the release of aggregated study data. 
No confidential information may be released without the express written consent of the study subjects. Only 
copies of the finalized data will be released. The original data file will remain in its pristine state. 
17. POTENTIAL BENEFITS 
Participants who increase their physical activity may experience a number of health benefits associated with a 
physically active lifestyle. Additionally, the results will be used to further understand the unique factors related 
to promoting physical activity adoption and maintenance among MA men, and will inform the design and 
testing of a larger trial. The risks to participants in this study are judged to be minor. 
18. RISK/BENEFIT RATIO 
The risks to participants in this study are judged to be minor. The anticipated benefits are great as the results 
will be used to further understand the unique factors related to promoting physical activity adoption and 
maintenance among Mexican and Mexican-American men. Health disparities and associated sedentary 
lifestyles remain an enormous public health problem. 
19. EXPENSE TO PARTICIPANT 
There will be no expenses for participation in the study.  
 
20. COMPENSATION FOR PARTICIPATION 
Phase 1 Compensation: To compensate participants for their time and travel, they will receive $10 for 
participating in the focus group session, and an additional $10 for transportation reimbursement. If they are 
asked to return for the confirmatory panel, they will receive an additonal $20. We will provide snack food for 
the participants to consume during their group or individual meeting.  Finally, participants will also receive 
validated parking to cover the cost of parking on the UCSD Campus during their meeting. If they decide to 
leave the study early, we will still cover the cost of their parking; however, they will only receive the $10 if they 
participate in the entire session (unless special circumstances occur). All monetary compensation will be in the 
form of SCRIP. 
 
Phase 2 Compensation: Participants will receive $10 for completing monthly questionnaires, and $25 for 
completing your in-person 6-month visit. Participants who complete all 6 monthly questionnaires will receive an 
additional $50 bonus incentive. In addition, participants will receive a $10 incentive for returning their 
accelerometer during the randomization visit.   If participants are not able to come to our office at 6 months but 
are able to complete parts of the assessment over the phone, they will be compensated with $10 for each 
partial assessment completed. To compensate participants for their travel, they will also receive $10 for each 
in-person visit. If they choose to complete any of your visits via phone, they will not receive compensation for 
travel. Participants will also receive $5 per month to defray the costs of the text messages. All monetary 
compensation will be in the form of SCRIP, a payment that resembles a check but does not contain their name 
or personal information.  Participants do not need to change their behavior (exercise more) to participate or 
receive the compensation. 
21. PRIVILEGES/CERTIFICATIONS/LICENSES AND RESEARCH TEAM RESPONSIBILITIES 
Dr. Bess Marcus, PhD, Principal Investigator. Dr. Marcus is a Professor and the Chair of the Department of 
Family and Preventative Medicine. Dr. Marcus has spent 25 years developing and studying methods for 
increasing physical activity among sedentary adults and has served as PI on numerous grants on this topic. 
Dr. Marcus will oversee all aspects of the project and will be responsible for the training and supervision of the 
staff and the scientific integrity of the project. She will also be responsible for monitoring the quality control of 
all aspects of the study. Dr. Marcus will be responsible for producing scientific reports and manuscripts based 
on the results of the study. 
 
Kevin Patrick, M.D. (Co-Investigator, Text-message development and implementation): Dr. Patrick has 
extensive research experience with formative research, survey methodology, measurement technologies, 

 
 
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behavioral interventions and information technology (IT). His work focuses upon the use of text messaging, 
smartphone apps, mobile video, the mobile web and Facebook apps to promote health behavior change. Dr. 
Patrick will oversee the development and implementation of the text-message enhancement for the 
intervention. 
 
James Sallis, Ph.D. (Co-Investigator, Built Environment): Dr. Sallis is a Distinguished Professor in the 
Department of Family & Preventive Medicine at UCSD with extensive experience with research focusing on 
physical activity and the built environment. Over the past 30 years he has led funded research projects on 
physical activity in a variety of populations, including Latinos, and has published more than 450 articles. Dr. 
Sallis will guide the development and the implementation of the intervention components targeting the built 
environment to increase physical activity. 
Jesse Nodora, Ph.D (Co-Investigator, Community Collaborations and Intervention Development): Dr. Nodora 
is a bilingual and bicultural Assistant Professor in the Department of Family & Preventive Medicine at 
UCSD.He will focus on developing community relationships to aid in recruitment as well as to help develop 
culturally relevant intervention content. As a co-investigator, he will also work closely with the research team 
to address participant recruitment as well as cultural factors related to Mexican and Mexican American men. 
 
Carlos Rojas, M.D. (Co-Investigator, Study Physician): Dr. Rojas is a bilingual and bicultural physician who is 
board certified in Family Medicine and Geriatric Medicine and is the Medical Director of Family Medicine at 
the Hillcrest offices of the UCSD Family Medicine Practice. Dr. Rojas will provide essential recruitment 
support by encouraging potentially eligible UCSD Family Medicine Practice patients to participate in the 
study, and by working with his fellow physicians to encourage referrals. Additionally, Dr. Rojas will provide 
consultation to Dr. Marcus regarding medically related participant eligibility matters.  
 
Shira Dunsiger, Ph.D. (Consultant): Dr.Dunsiger at The Miriam Hospital and Brown University School of Public 
Health, has considerable expertise in statistical methods for longitudinal and incomplete data; she is active in 
developing new statistical methodology for analyzing longitudinal data from behavioral medicine, and has 
collaborated with Dr. Marcus and other investigators on studies related to both exercise promotion and 
smoking cessation. Dr. Dunsiger will oversee all statistical aspects of the project and will formulate the primary 
and secondary analyses. She will be responsible for the development of statistical models for the analysis of 
the primary and secondary aims and collaborating on scientific reports and manuscripts based on the results 
of the study. Dr. Dunsiger is currently the biostatistician for Dr. Marcus’s projects R01CA15995401, 
R21NR009864, and R01NR011295, which utilize many of the same measures and analyses as the current 
study.  
 
Dorothy Pekmezi, Ph.D. (Consultant): Dr.Pekmezi at The University of Alabama at Birmingham, has 
extensive experience conducting qualitative research and in culturally adapting physical activity interventions 
for underserved populations. She has served as a Co-Investigator on several of Dr. Marcus’ studies culturally 
adapting and assessing physical activity interventions for Latinas (R21NR009864, R01NR011295). As a 
consultant, Dr.Pekmezi will participate in structuring and conducting focus groups and expert panels in 
Phase 1. She will also help develop and conduct follow-up interviews after the pilot trial, which will help 
develop the texting component. Dr.Pekmezi will also participate in developing the quality control procedures 
and conducting the quality control for the intervention and for the measurements. She will also provide 
feedback to the study staff and ensue the quality of the intervention delivery and assessment throughout the 
study period.  
 
Sheri Hartman, Ph.D. (Collaborative Investigator): Dr. Hartman is an Assistant Professor in the Department 
of Family and Preventive Medicine with an established history of working with Dr. Marcus' team as a Co-
Investigator on numerous grant-funded studies including a grant testing an internet intervention to increase 
physical activity in Latinas (RO1CA159954).  Dr. Hartman is clinical psychologist with extensive training and 
experience promoting health behavior change.  She has developed quality control procedures and 

 
 
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conducted the quality control evaluations for two grant funded studies (R01DK064902, R18DK079880). For 
the current study Dr. Hartman will advise on developing the quality control procedures and conducting the 
quality control for the intervention and for the measurements. In addition, Dr. Hartman will assist with report, 
abstract, manuscript, and grant preparations.  
 
Sarah Linke, Ph.D., M.P.H. (Collaborative Investigator): Dr. Linke is an Assistant Clinical Professor in the 
Department of Family Medicine & Public Health with an established history of working with Dr. Marcus' team 
on numerous grant-funded studies including a grant testing an internet intervention to increase physical 
activity in Latinas (RO1CA159954). Dr. Linke is clinical psychologist with extensive training and experience 
promoting health behavior change. She led the development and modification of the website for a similar 
study examining the effects of an Internet-based PA intervention for Latinas (RO1CA159954). For the 
current study, Dr. Linke will lead the oversight of the text messaging component. In addition, Dr. Linke will 
assist with staff supervision, human subjects protection, and report, abstract, manuscript, and grant 
preparations.  
 
Britta Larsen Ph.D. (Collaborative Investigator): Dr. Larsen is an Assistant Professor in the Department of 
Family and Preventive Medicine at UCSD. She has worked in supportive roles on Dr. Marcus’ PA 
intervention studies with Latinas, and served as the project director for intramurally funded research 
adapting and testing this intervention for Mexican and Mexican American men. For the current study Dr. 
Larsen will advise on the focus groups, and help develop the texting component. She will also assist with 
preparing manuscripts based on study findings.  
 
Raul Fortunet (Study Coordinator, Intervention Delivery): Mr. Fortunet is bilingual and bicultural and will be 
responsible for consenting participants, delivering the intervention, conducting randomization sessions and 
goal setting, training research staff, recruitment activities, participant tracking, and conducting focus groups. 
Mr. Fortunet has worked with Dr. Marcus for four years and has significant experience with managing study 
logistics, delivering culturally adapted interventions, and ensuring high-quality control of the research protocol. 
He has performed similar duties in two of our other studies (R01NR011295; R01CA159954) and has 
established standard operating procedures as well as quality control checks to ensure efficient intervention 
delivery. 
 
Andrea Mendoza, M.P.H. (Research Associate for Assessment): Ms. Mendoza has a M.P.H. degree in 
Health Promotion, Education and Evaluations as well as a BA in Film Studies and Computer Science. 
She is bilingual and bicultural and will be responsible for all assessment-related tasks including 
conducting orientation, measurement, and follow-up visits. She will also be responsible for telephone 
screening for eligibility, scheduling of participants, and data entry. 
 
Mario Munoz, Ph.D. (Assistant Project Director): Dr.Munoz is a Postdoctoral Employee in the Department 
of Family Medicine & Public Health. He has a PhD in Rehabilitation Sciences with a background in 
exercise sciences. He will be responsible for fostering relationships with community contacts and 
overseeing all recruitment activities which will include use of local media outlets (newspaper and radio), 
flyers distributed and posted at community events or sites, presentations at community functions or 
centers, and the community clinics. He will also be responsible for telephone screening for eligibility, 
scheduling of participants, and data entry. 
 
Mayra Cano (Research Assistant): Ms. Cano is a bicultural, bilingual researcher currently working as a 
research assistant in our lab. She will conduct baseline and six month assessments as well as data entry, 
and will be responsible for administrative tasks of the study, telephone screening for eligibility, consenting 
participants and scheduling of participants. To ensure scientific rigor as well as avoidance of inadvertent 
study contamination due to interviewer knowledge of assigned condition, she will have no knowledge of 
condition assignment when conducting assessment interviews. She is already trained in interview protocol 
(including certification for conducting the 7-Day Physical Activity Recall) as well as quality control measures, 
and is well versed in the research application of accelerometers that will be mailed to participants (to be 

 
 
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worn during the week prior to assessment interviews) as well as the downloading and cleaning of data from 
these devices. 
22. BIBLIOGRAPHY 
Larsen, B. A., Dunsiger, S., Hartman, S., Nodora, J., Pekmezi, D., Marquez, B., Noble, M.L., Rojas, C., & 
Marcus, B. H. (2014). Activo: Assessing the feasibility of designing and implementing a physical activity 
intervention for Latino men. International Journal of Men’s Health, 13(1), 60-71. 
 
Larsen, B. A., Noble, M. L., Murray, K. E., & Marcus, B. H. (2014). Physical activity in Latino men and women: 
Facilitators, barriers, and interventions. American Journal of Lifestyle Medicine. doi: 
10.1177/1559827614521758. 
 
Patrick K, Raab F, Adams MA, et al. A text message-based intervention for weight loss: randomized controlled 
trial. J Med Internet Res. 2009;11(1) 
23. FUNDING SUPPORT FOR THIS STUDY 
NIH/NINR R21NR014911 
 
24. BIOLOGICAL MATERIALS TRANSFER AGREEMENT 
Not applicable.  
 
25. INVESTIGATIONAL DRUG FACT SHEET AND IND/IDE HOLDER 
Not applicable.  
 
26. IMPACT ON STAFF 
Not applicable.  
 
27. CONFLICT OF INTEREST 
None. 
 
28. SUPPLEMENTAL INSTRUCTIONS FOR CANCER-RELATED STUDIES 
Not applicable.  
 
29. OTHER APPROVALS/REGULATED MATERIALS 
None. 
 
30. PROCEDURES FOR SURROGATE CONSENT AND/OR DECISIONAL CAPACITY ASSESSMENT 
None. 
 
 
 
 

Statistical Analysis Plan 
 
The primary aim of our pilot trial is to determine the feasibility and acceptability of the text-enhanced PA 
intervention. We will consider the intervention feasible if at least 80% of participants are retained at the 6-
month follow-up. The intervention will be considered acceptable if at least 80% of participants respond 
favorably (“satisfied” or “very satisfied”) to the question “In general how satisfied were you with the 
intervention?”. Although interest is in the feasibility and acceptability of the text-enhanced PA intervention 
arm, we will calculate these rates for both groups and compare them using chi-squared tests. In addition, 
our data analytical strategy is designed to examine whether there are treatment effects favoring the text-
enhanced PA intervention while assuring control for potential confounds not adequately controlled for by 
the randomization. Thus as a preliminary step, we will assess potential between-group differences in 
baseline characteristics (demographics, baseline activity level) using graphical methods, non-parametric 
and parametric tests as appropriate (e.g., Wilcoxin rank-sum test for skewed data, t-tests for normally 
distributed continuous data & chi-squared tests for categorical data). Any variables not balanced by 
randomization will be controlled for as covariates in subsequent analyses. We will estimate the 
preliminary efficacy of intervention compared to control using a generalized linear model in which we 
regress minutes/week of moderate to vigorous PA (as measured by accelerometers) at 6 months on 
treatment assigned, baseline value of the outcome and potential confounders (including those variables 
not balanced by randomization). To avoid the effects of outliers, we will apply a normalizing 
transformation (if necessary) to the outcome prior to analysis. Modeling is done using a likelihood-based 
approach and thus makes use of all available data (intent-to-treat sample) to produce consistent 
estimates of the regression parameters. We are aware that effect size estimates with small samples have 
large standard errors and wide confidence intervals. To determine the sample size for a clinical trial, the 
trial needs to have adequate power to detect a clinically relevant difference between treatment