Comparison of two methods of conducting the fit and strong! program


  • identifier: NCT00421681.

  • The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute on Aging or the NIH.



Fit and Strong! is an award winning, evidence-based, multiple-component physical activity/behavior change intervention. It is a group- and facility-based program that meets for 90 minutes 3 times per week for 8 weeks (24 sessions total). We originally tested Fit and Strong! using physical therapists (PTs) as instructors but have transitioned to using nationally certified exercise instructors (CEIs) as part of an effort to translate Fit and Strong! into community-based settings, and have tested the impact of this shift in instruction type on participant outcomes.


We used a 2-group design. The first 161 participants to sequentially enroll received instruction from PTs. The next 190 sequential enrollees received instruction from CEIs. All participants were assessed at baseline, at the conclusion of the 8-week Fit and Strong! program, and at the 6-month followup.


We saw no significant differences by group on outcomes at 8 weeks or 6 months. Participants in both groups improved significantly with respect to lower-extremity strength, aerobic capacity, pain, stiffness, and physical function. Significant differences favoring the PT-led classes were seen on 2 of 5 mediators, self-efficacy for exercise and barriers adherence efficacy. Participant evaluations rated both types of instruction equally highly, attendance was identical, and no untoward health events were observed or reported under either instruction mode.


Outcomes under the 2 types of instruction are remarkably stable. These findings justify the use of CEIs in the future to extend the reach of the Fit and Strong! program.


Given the dramatic growth in the number of older adults in the US and the high prevalence of sedentary lifestyles among them, the need to efficiently and effectively translate and diffuse evidence-based physical activity programs specifically designed for this population is paramount. The need to diffuse evidence-based programming for older adults with osteoarthritis (OA) is particularly acute. OA is not only the most common chronic condition among older adults, but is also a major barrier to participation in physical activity, and is a known risk factor for disability and institutionalization (1, 2). Fit and Strong! is an evidence-based physical activity/behavior change program that effectively targets this high-risk group. It addresses documented strength and aerobic deficits in this population and is inexpensive and simple to replicate (3, 4).

Fit and Strong! is a multiple-component physical activity/behavior change intervention. It is a group- and facility-based program that meets for 90 minutes 3 times per week for 8 weeks (24 sessions total). The first 60 minutes consist of a multiple-component exercise program that incorporates flexibility/balance, aerobic walking and/or low-impact aerobics, and lower-extremity strength training using elastic exercise bands and adjustable ankle cuff weights. The remaining 30 minutes of each session are devoted to group problem solving and education using a curriculum designed to facilitate arthritis symptom management, self-efficacy for exercise, and commitment to lifestyle change (5). In week 6, participants meet with instructors to develop an individualized physical activity plan of their choice that can include home-based exercise or an ongoing group/facility-based program (or a combination of the 2) with the goal of maintaining 20 minutes of flexibility, 20 minutes of aerobic activity, and 20 minutes of resistance training for a minimum of 3 times per week. This plan becomes a physical activity maintenance contract that each participant signs at a graduation ceremony on the last day of class.

We previously tested the efficacy of Fit and Strong! in a randomized trial with 215 treatment and control participants (5, 6). Relative to controls, treatment participants experienced statistically significant improvements in self-efficacy for exercise (P = 0.001), exercise participation (P = 0.000), and lower-extremity stiffness (P = 0.018) at the conclusion of the Fit and Strong! program, 8 weeks after baseline. These benefits were maintained at 6 months when several other outcomes also were significant: increased time adherence efficacy (P = 0.001), reduced lower- extremity pain (P = 0.040), and (marginally significant) increased self-efficacy for arthritis pain management (P = 0.052). Despite a substantially smaller sample size at 12 months, significant treatment effects were maintained on self-efficacy for exercise (P = 0.006) and exercise participation (P = 0.001), which were accompanied by marginally significant reductions in lower-extremity stiffness (P = 0.056) and pain (P = 0.066). No adverse health effects were reported. Effect sizes in the treatment group for exercise self-efficacy and exercise participation were 0.798 and 0.713 at 6 months, respectively, and were 0.905 and 0.669 at 12 months, respectively.

In an effort to minimize harm to participants, we originally developed and tested Fit and Strong! using physical therapists (PTs) who had a substantial amount of experience working with older adults. In 2003, we obtained a National Institute on Aging grant to replicate Fit and Strong! at 7 senior centers in Chicago and to compare different methods of fostering maintenance of physical activity after Fit and Strong! ended. Most evidence-based programs need to be adapted when they are diffused into the community (7, 8). We were concerned that reliance on a program led by PTs could limit the reach of Fit and Strong! in poor and underserved communities. Therefore, we used the current study as an opportunity to refine Fit and Strong! training materials and to shift from using PT instructors to using certified exercise instructors (CEIs). We made this shift in the middle of the study, which enabled us to compare outcomes under the 2 different instruction types. Here we compare the outcomes collected for 161 PT-led participants with those collected for 190 CEI-led participants.



We used a 2-group pretest/post-test design to evaluate the impact of this adaptation in the mode of instruction of the Fit and Strong! program. We hypothesized that participants in both modes of instruction would have comparable outcomes at 8 weeks and 6 months. Participants were assessed at baseline (prior to inclusion in the program), at the 8-week conclusion of the Fit and Strong! program, and at 6 months after baseline.


The study was conducted at local senior centers. Participants were community-dwelling older adults who were recruited by newsletters, local media announcements, and presentations to senior groups. Importantly, participants were recruited from the same sources and received the program in the same settings under both modes of instruction.

Inclusion and exclusion criteria.

People were considered ineligible if they were <60 years of age, currently participating in an exercise program, had undergone uncomplicated hip or knee surgery within the previous 6 months or complicated surgery within the past year, had received steroid injections within the previous 3 months, had moderate to severe cognitive impairment, had rheumatoid arthritis, or had diabetes mellitus or blood pressure that was not under good control.

Potential enrollees were also examined by the study rheumatologist to determine clinical presence of OA of the hip or knee and to rate degree of functional significance using a modified version of the American College of Rheumatology (ACR; formerly the American Rheumatism Association) functional class (9). Clinical criteria for the presence of knee OA were knee pain in addition to ≥3 of the following 6 clinical findings: morning stiffness <30 minutes' duration, crepitus on active motion, tenderness of the bony margins of the joint, bony enlargement on examination, and a lack of palpable warmth of the synovium (10). Persons were classified as having hip OA, based on the ACR criteria (11), if pain was present in combination with either 1) hip internal rotation ≥15 degrees, pain present on internal rotation of the hip, morning stiffness of the hip for ≤60 minutes, or 2) hip internal rotation <15 degrees and hip flexion ≤115 degrees (sensitivity 86% and specificity 75%).


We used the 10-item Short Portable Mental Status Questionnaire to screen for presence of moderate to severe cognitive impairment (12).

The following mediators and outcomes were assessed at baseline, at the end of the 8 week Fit and Strong! program, and at 6 months after baseline for all participants.

Self-efficacy for self-management and exercise adherence.

Self-efficacy to perform self-management tasks was assessed using 3 subscales of the Arthritis Self-Efficacy Scale (ASES) developed by Lorig et al: self-efficacy for exercise (3 items), self-efficacy for pain management (5 items), and self-efficacy for other symptom management (6 items) (13, 14). All 3 subscales have 10-point response formats and are scored by calculating an overall subscale mean.

We used 2 scales developed by McAuley and colleagues to measure self-efficacy for exercise adherence (15). The barriers adherence scale (13 items) measures self-efficacy to adhere to exercise in the presence of barriers. The time adherence measure (6 items) requires respondents to rate their self-efficacy to continue participating in regular exercise over a period of 6 months. Both scales have 0–100-point response formats and are scored by calculating an overall mean score, with higher scores indicating higher levels of self-efficacy.


Attendance was monitored and documented at each session.

Exercise maintenance.

We used the Community Healthy Activities Model Program (CHAMPS) measure to assess maintenance of physical activity. The CHAMPS has 41 items that assess participation in leisure-time, moderate and vigorous physical activity, and nonexercise activities (e.g., reading, church attendance, volunteering). The CHAMPS provides frequencies of exercise participation and estimates of weekly caloric expenditure, and is valid, reliable, and sensitive to change (16).

Functional lower-extremity muscle strength.

We used the timed-stands test to functionally assess lower-extremity muscle strength and endurance (17). Participants were asked to sit in a straight-backed chair and rise with their arms folded (10). If they successfully rose, they were asked to stand and sit down 5 times as quickly as possible. Raw scores were transformed into a rate per minute to assess change in those who were unable to perform the test at any point.

Functional exercise capacity.

We used the 6-minute walk test to measure functional exercise capacity (18). Participants were asked to walk for 6 minutes, accompanied by research staff who measured the distance walked in feet.

Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

We used the WOMAC self-report instrument to examine lower-extremity pain (5 items), stiffness (2 items), and physical function (17 items) (19).

Participant program evaluations.

All Fit and Strong! participants completed a 75-item program evaluation that assessed participants' satisfaction with the physical environment, exercise program, group discussion sessions, program manual, and overall satisfaction with the instructor and program.

Independent variables.

Participant demographic variables included participants' age, race, sex, income, and education. The primary independent variable, instructor type, was coded 1 for PT-led groups and 0 for CEI-led groups. PTs were required to have a bachelor's or master's degree in physical therapy, current PT licensure (with the American Physical Therapy Association), liability insurance, and experience working with older adults with OA. They were recruited through postings at hospitals, clinics, and universities, and through referrals. Six PTs conducted the first 12 sessions of the Fit and Strong! program.

CEIs were recruited through online postings, instructor certification Web sites, and referrals. We sought CEIs who had experience in group fitness instruction and in working with older adults. The instructors were required to have some type of nationally recognized certification (e.g., from the Aerobic and Fitness Association of America or the American College of Sports Medicine) and possess liability insurance. Certification programs vary by organization, but are typically offered in a classroom format, manual-based for home study, or online. The courses include information on anatomy and physiology, appropriate technique, health behavior change strategies, injury prevention, principles of group exercise, instruction guidelines, class formats, and working with special populations. Although not a requirement, many CEIs had earned college degrees in a health-related field (e.g., exercise physiology, nutrition). Six CEIs instructed the next 9 Fit and Strong! sessions.

PTs and CEIs participated in a half day of training before beginning instruction. The training was led by the principal investigator (SLH), the study PT (GMH), and the project manager (PD). Training included an overview of how to work with older adults and people with OA, the background of the study, a detailed description of the components of the Fit and Strong! program, and implementation issues. The PT training devoted more time on how to lead a class and engage participants in group exercises by varying routines. The CEI training devoted more time to describing the symptoms of OA and the types and intensity of exercises that are appropriate for older adults with OA. Project staff, including the principal investigator and the study PT, conducted site visits to assist the instructors and monitor the fidelity of the program. Adherence to the exercise routine, appropriateness of modifications to exercises for participants of varying levels of ability, and facilitation of the group problem solving and education component were assessed. Feedback was provided to instructors following each site visit. Site visits were conducted at a minimum on the first day of class, at the midpoint, and on the last day of class.

Statistical analyses.

We examined overall changes in study outcomes using a random-effects model to account for repeated measures. Data analysis involved 1 between-subjects factor (PT-led versus CEI-led class) and 1 within-subject factor (time). We treated time nonlinearly by including indicator variables for the 2 measurement points. Because we had repeated-measures data and different numbers of respondents by instructor type over time, we analyzed the data using a random intercept model, which assumes that data are missing at random, conditional on covariates. A simple random-effects model for the data can be written as:

equation image

where the interaction terms “Instruct×Time2” and “Instruct×Time6” test whether the effectiveness of the 2 instructor types changed differently over time. We included 1 covariate, ACR functional class, in order to control for baseline disease severity


Baseline characteristics of participants by instructor type are shown in Table 1. Across both groups, participants had a mean age of 71 years (not shown), and the majority were female, white, had annual incomes <$30,000, had at least a high school education, and had class II ACR functional scores. Approximately 64% of the total sample also reported the presence of hypertension, 24% reported diabetes mellitus, and 15% reported other cardiovascular disease. Importantly, no significant differences were noted by instructor type on any of the demographic or disease measures.

Table 1. Participant baseline demographic characteristics by instruction mode*
 PT (n = 161)CEI (n = 190)P
  • *

    Values are the percentage of patients unless otherwise indicated. PT = physical therapist; CEI = certified exercise instructor; ACR = American College of Rheumatology (ref.9).

Age, mean years71.670.70.310
 Less than high school15.311.90.712
 High school19.124.4 
 More than high school65.763.8 
Income <$20,00031.139.50.870
 African American58.847.5 
 Asian/Pacific Islander3.81.9 
ACR functional class   


Similar proportions (19 [16%] of PT-led participants and 27 [18%] of CEI-led participants) failed to complete the Fit and Strong! program. The 3 most common reasons for class dropout were health concerns (n = 22), time/schedule conflicts (n = 14), and care giving responsibilities (n = 3). No significant differences between PT- and CEI-led class participants were found for Fit and Strong! class attendance (20.0 classes [83%] attended versus 19.1 classes [80%] attended).

Post-test attrition.

Eight-week post-tests were obtained for 73% of PT group participants (n = 117) and 79% of CEI group participants (n = 151). At 6 months, post-tests were obtained on 58% of PT-led participants (n = 93) and 68% of CEI-led participants (n = 129). A logistic regression model compared those who remained in the study (responders) with those who left (nonresponders) (20). We regressed a variable indicating continued participation in the study on each of the baseline values of the outcome variables, a dummy variable for instructor type, and the interaction of the two. These analyses demonstrated no significant differences between responders and nonresponders on any of the outcome measures (Table 2). Importantly, the comparison in attrition rate between responders and nonresponders by instructor type was not significant (P = 0.142). The analyses also found no statistically significant differences between responders and nonresponders on demographic characteristics, arthritis severity, or on the baseline values of the outcome measures. However, nonresponders had slightly worse scores on the outcome measures at baseline.

Table 2. Attrition: logistic regression comparing participant responders and nonresponders*
 Nonattrition (n = 268)Attrition (n = 81)ORP
  • *

    Values are the mean ± SD unless otherwise indicated. OR = odds ratio; PT = physical therapist; CEI = certified exercise instructor; WOMAC = Western Ontario and McMaster Universities Osteoarthritis Index.

  • For effect of instructor type (PT versus CEI) or interaction of instructor type by variable in row.

Instructor type, no.    
 PT11742 0.142
Exercise maintenance    
 Frequency of all exercise16.45 ± 11.5014.95 ± 11.980.990.628
 Frequency of moderate exercise4.59 ± 5.993.98 ± 5.921.000.986
 Caloric expenditure, all exercise3,341.41 ± 2,715.933,205.99 ± 3,224.460.920.743
 Caloric expenditure, moderate exercise1,283.34 ± 1,815.821,270.80 ± 2,
Performance measures    
 Functional lower-extremity muscle strength: timed-stands test20.61 ± 6.9919.87 ± 7.351.000.947
 Functional exercise capacity: 6-minute walk1,099.45 ± 334.071,025.04 ± 366.240.830.789
 Pain, range 0–205.66 ± 3.686.06 ±
 Stiffness, range 0–83.23 ± 1.623.46 ± 1.721.010.946
 Physical function, range 0–6822.13 ± 13.4825.07 ± 14.550.990.746

Program evaluations.

No significant differences between groups were found on responses to the program evaluations. Across all domains assessed, participants in both conditions were overwhelmingly positive about the Fit and Strong! program. One hundred percent of PT-led participants and 99% of CEI-led participants rated their overall reaction to the Fit and Strong! instructor as excellent or good. In both instruction groups, 98% of participants felt that they benefited from the Fit and Strong! program, and 99% of participants incorporated information learned during Fit and Strong! into their lifestyle. There were considerable site differences in responses to questions about environment (e.g., temperature, parking), but no differences related to instructor type.

Baseline, 8-week, and 6-month findings.

Raw scores for mediators and outcomes are shown broken down by instruction type in Table 3. Pretest/post-test findings on mediators and outcomes for the entire sample of participants, with main effects displayed first and then broken down by type of instruction, are shown in Table 4. Examination of scores for the total sample revealed that participants as a whole changed significantly at 8 weeks relative to baseline on 2 mediators: self-efficacy for other symptom management and barriers adherence efficacy (Table 4). Self-efficacy for other symptom management increased significantly, whereas barriers adherence self-efficacy declined significantly between baseline and 8 weeks and this decline was maintained at 6 months. No significant pretest/post-test differences were seen on self-efficacy for exercise, pain management, or time adherence. Participants as a whole also improved significantly at 8 weeks on frequency of participation in all and moderate exercise activities, caloric expenditure on all and moderate exercise activities, the timed-stands test, the 6-minute walk test, stiffness, and physical function. These benefits were maintained at 6 months.

Table 3. Baseline, 8-week, and 6-month outcomes over time by instructor type*
 Physical therapistCertified exercise instructor
Baseline (n = 161)8 weeks (n = 117)6 months (n = 93)Baseline (n = 190)8 weeks (n = 151)6 months (n = 129)
  • *

    Values are the mean ± SD unless otherwise indicated. ASES = Arthritis Self-Efficacy Scale; CHAMPS = Community Healthy Activities Model Program; WOMAC = Western Ontario and McMaster Universities Osteoarthritis Index.

  • Increase in score indicates positive improvement.

  • Decrease in score indicates positive improvement.

ASES subscales, range      
 Exercise, 1–107.25 ± 2.218.15 ± 1.857.61 ± 2.066.91 ± 2.216.51 ± 2.806.92 ± 2.30
 Pain management, 1–107.33 ± 1.837.45 ± 1.857.39 ± 1.877.28 ± 1.717.63 ± 1.827.16 ± 1.98
 Other symptom management, 1–107.49 ± 1.857.90 ± 1.667.71 ± 1.647.55 ± 1.517.92 ± 1.627.62 ± 1.79
McAuley self-efficacy scales, range      
 Barriers adherence, 0–10069.05 ± 19.7065.34 ± 21.9864.52 ± 20.6165.81 ± 19.9152.41 ± 24.5451.06 ± 23.40
 Time adherence, 0–10076.70 ± 22.9081.39 ± 19.1977.44 ± 20.2373.88 ± 21.1372.87 ± 25.4869.22 ± 28.67
CHAMPS exercise maintenance      
 Frequency of all exercise16.19 ± 11.5921.13 ± 9.9219.75 ± 11.2915.62 ± 11.1020.40 ± 10.6718.61 ± 12.88
 Frequency of moderate exercise4.63 ± 5.907.87 ± 5.986.54 ± 6.584.16 ± 6.187.72 ± 5.696.81 ± 8.04
 Caloric expenditure, all exercise3,536.43 ± 3,318.304,119.82 ± 2,634.764,006.82 ± 2,963.833,036.62 ± 2,374.734,196.17 ± 3,088.543,428.35 ± 2,688.38
 Caloric expenditure, moderate exercise1,459.38 ± 2,228.682,013.82 ± 1,812.751,765.69 ± 1,887.781,081.28 ± 1,593.052,274.32 ± 2,332.341,546.84 ± 1,854.09
Performance measures      
 Functional lower-extremity strength: timed-stands test20.79 ± 7.9223.80 ± 7.4023.70 ± 8.3020.20 ± 6.8123.67 ± 7.9323.81 ± 7.58
 Functional exercise capacity: 6-minute walk1,083.79 ± 346.011,167.63 ± 339.081,150.68 ± 293.561,097.09 ± 306.381,206.87 ± 400.911,271.40 ± 719.74
WOMAC subscales, range      
 Pain, 0–205.89 ± 3.825.33 ± 3.865.14 ± 3.715.38 ± 3.595.22 ± 3.815.26 ± 3.64
 Stiffness, 0–83.36 ± 1.662.82 ± 1.632.93 ± 1.773.23 ± 1.582.87 ± 1.772.98 ± 1.79
 Physical function, 0–6822.63 ± 13.9719.14 ± 13.8519.38 ± 13.8722.32 ± 13.8019.85 ± 14.0719.01 ± 12.48
Table 4. Random-effects model: baseline, 8-week, and 6-month outcomes by time and instructor type*
 Main effectInteraction: instructor by time
8 weeks6 monthsACR functional classInstructor typeTime2×insTime6×ins
  • *

    Values are the coefficient, Z score (P). Physical therapist–led groups are coded 1 and certified exercise instructor–led groups are coded 0. ACR = American College of Rheumatology (formerly the American Rheumatism Association) Time2×ins = time 2 × instructor type; Time 6×ins = time 6 × instructor type. See Table 3 for additional definitions.

  • Increase in score indicates positive improvement.

  • P was significant.

  • §

    Decrease in score indicates positive improvement.

ASES subscales, range      
 Exercise, 1–100.246, 1.49 (0.135)0.035, 0.2 (0.844)−0.739, −3.01 (0.003)0.849, 3.88 (0.000)1.12, 3.44 (0.001)0.329, 0.93 (0.352)
 Arthritis pain management, 1–100.186, 1.55 (0.121)0.101, 0.66 (0.511)−0.634, −3.09 (0.002)−0.059, −0.32 (0.752)−0.129, −0.54 (0.592)−0.256, −0.77 (0.438)
 Symptom management, 1–100.299, 3.05 (0.002)0.128, 1.01 (0.313)−0.627, −3.18 (0.001)−0.000, −0.00 (0.999)0.085, 0.43 (0.664)−0.087, −0.32 (0.748)
McAuley self-efficacy scales, range      
 Barriers efficacy, 0–100−9.866, −5.80 (0.000)−11.814, −6.55 (0.000)−5.733, −2.52 (0.012)9.792, 4.82 (0.000)11.421, 3.39 (0.001)11.492, 3.21 (0.001)
 Adherence efficacy, 0–1000.095, 0.06 (0.951)−4.065, −2.41 (0.016)−4.124, −1.58 (0.113)6.556, 2.82 (0.005)5.195, 1.66 (0.098)3.362, 0.99 (0.320)
CHAMPS exercise maintenance      
 Frequency of all exercise-related activity4.859, 6.75 (0.000)3.455, 4.43 (0.000)−3.913, −3 (0.003)1.121, 0.96 (0.336)0.924, 0.64 (0.522)1.640, 1.05 (0.295)
 Frequency of moderate exercise activities3.427, 8.27 (0.000)2.385, 5.31 (0.000)−1.618, −2.16 (0.031)0.109, 0.16 (0.871)−0.246, −0.29 (0.768)−0.114, −0.13 (0.900)
 Caloric expenditure for all exercise, ln0.459, 6.60 (0.000)0.365, 4.57 (0.000)−0.215, −1.79 (0.073)0.062, 0.56 (0.575)−0.200, −1.38 (0.167)−0.020, −0.12 (0.907)
 Caloric expenditure for moderate exercise, ln0.387, 4.77 (0.000)0.379, 3.85 (0.000)−0.316, −2.20 (0.028)0.111, 0.84 (0.400)−0.127, 0.08 (0.456)0.255, 1.21 (0.227)
Performance measures      
 Functional lower-extremity muscle strength: timed- stands test3.309, 7.68 (0.000)3.374, 7.11 (0.000)−1.634, −1.66 (0.096)0.903, 1.03 (0.303)−0.375, −0.43 (0.665)−0.219, −0.23 (0.819)
 Functional exercise capacity: 6-minute walk test, ln0.065, 2.30 (0.021)0.096, 3.13 (0.002)−0.144, −2.61 (0.009)−0.033, −0.67 (0.501)−0.018, −0.32 (0.749)−0.044, −0.71 (0.479)
WOMAC subscales, range§      
 Pain, 0–20−0.365, −1.82 (0.069)−0.252, −1.15 (0.250)1.037, 2.41 (0.016)0.478, 1.24 (0.214)−0.396, −0.99 (0.324)−0.620, −1.41 (0.157)
 Stiffness, 0–8−0.462, −4.45 (0.000)−0.359, −3.18 (0.001)0.267, 1.45 (0.146)0.130, 0.80 (0.427)−0.163, −0.78 (0.433)−0.118, −0.52 (0.604)
 Physical function, 0–68−2.625, −3.76 (0.000)−2.659, −3.47 (0.001)5.139, 3.13 (0.002)−0.258, −0.18 (0.859)−1.111, −0.79 (0.427)−0.812, −0.53 (0.599)


ASES subscales.

A significant difference (P = 0.001) was seen favoring PT-led class participants at 8 weeks on the exercise efficacy subscale. This difference was not maintained at 6 months. PT-led participant scores increased by ∼1 point at 8 weeks, whereas CEI-led group scores declined by four-tenths of a point. At 6 months, PT-led participant scores decreased almost to baseline levels, whereas CEI-led participant scores increased to baseline levels. The interactions between instructor type and time on the pain and symptom management subscales at 8 weeks and 6 months were not significant.

McAuley barriers and time exercise adherence efficacy.

A significant difference favoring the PT-led classes was seen on the barriers adherence self-efficacy scale (P = 0.001) at 8 weeks and 6 months. Barriers adherence declined significantly by 13 points across both groups between baseline, 8 weeks, and 6 months. However, less decline was experienced in the PT-led group (7% versus 22%, respectively). The interaction between instructor type and time on the time adherence self-efficacy scale was not significant at 8 weeks or 6 months.



Participants in both groups reported significant increases in weekly frequency of participation in all and moderate physical activities, and in caloric expenditure at 8 weeks and 6 months. The interactions between instructor type and time were not significant for any of the 4 CHAMPS measures at 8 weeks or 6 months.

Timed-stands test.

Participants in both PT- and CEI-led classes demonstrated significant improvement on the timed-stands measure between baseline and 8 weeks (P = 0.000) and baseline and 6 months (P = 0.000). The interaction between instructor type and time was not significant for this measure.

Six-minute walk test.

Participants in both instructor types demonstrated significant improvements at 8 weeks (P = 0.021) and 6 months (P = 0.000). A slightly greater improvement occurred among CEI-led class participants (90.73-meter improvement versus a 70.16-meter improvement). The interaction between instructor type and time for the 6-minute walk scores was not significant at 8 weeks (P = 0.749) or 6 months (P = 0.47).

WOMAC and adverse health outcomes.

Pain scores improved slightly in both groups between baseline and 8 weeks. Joint stiffness decreased among participants in both PT- and CEI-led classes at 8 weeks and 6 months, as did functional impairment at the same time points. As evidenced by the interaction between instructor type and time, no significant differences were seen between PT- and CEI-led participants on the WOMAC pain, stiffness, or physical function subscales. No adverse health outcomes were reported by participants in either type of instruction.


Although the need to adapt evidence-based programs in order to maximize their diffusion into community settings is widely recognized, little evidence to our knowledge has been reported in the literature regarding the impact of adaptations on program participants (21, 22). In several studies, Lorig and colleagues evaluated implementing the Chronic Disease Self-Management Program using different modes of delivery and different levels of instructors. The first Lorig study randomized participants to either the traditional, small-group version of the Chronic Disease Self-Management Program or to an Internet-based version of the program (23). After 1 year, participants in both groups experienced significant improvement in health status. The second study compared lay-taught and professional-taught arthritis self-management courses in order to assess the impact of different levels of instructors (24). Participants under both modes of instruction improved significantly on knowledge compared with a no-treatment control group. However, professional-led participants had a significantly larger improvement in knowledge at 4 months, whereas those in the lay-led groups improved significantly relative to professional-led participants on the practice of relaxation. The results of both studies suggest that similar outcomes can be achieved with varying levels of instructor education and modes of delivery.

Aside from the Lorig studies, we could not find any studies that compared outcomes achieved by varying levels of professional leaders or by different levels of instructors of exercise interventions. Our current article addresses this gap in the literature by providing findings from our recent adaptation of the type of instruction used in the Fit and Strong! program. Findings from our analyses demonstrate that when participants were aggregated across both types of instruction they improved significantly with respect to exercise participation, caloric expenditure, lower-extremity stiffness, physical function, and on performance measures that assessed lower-extremity strength and aerobic capacity.

Importantly, when findings were examined separately by instructor group, no adverse events were reported by participants, attendance levels were virtually identical, and both types of instructors were highly rated by participant evaluations. Superior results were experienced by the PT-led group participants on 2 of 5 self-efficacy measures used as mediators in this study: self-efficacy for exercise and barriers adherence efficacy. Exercise self-efficacy scores increased among PT-led participants and decreased slightly for CEI-led participants at 8 weeks, but at 6 months no differences were seen by instruction type. Barriers adherence efficacy scores decreased under both modes of instruction, but PT-led participants experienced less decline than CEI-led participants (a 4.5-point decrease versus a 14.8-point decrease).

Our findings of an impact on outcomes with or without a diminution of strength in mediators are somewhat unusual and counterintuitive to theory. It is possible that PT-led participants differentially improved on self-efficacy for exercise and experienced less decline in barriers adherence efficacy because the clinical training of PTs is geared to therapeutic exercise. The clinical training for PTs may put more emphasis on individual mastery of the exercises in order to achieve independent function. However, no differences on adherence, pain, stiffness, physical function, or performance outcomes were seen according to instructor type at 6 months despite the differences seen in these two self-efficacy variables. The differential self-efficacy findings may also indicate that the training for the CEIs should be expanded to accommodate more emphasis on techniques to foster self-efficacy while still addressing the special exercise needs of older adults with OA. Partially in response to these findings, we have increased the CEI training time from a half day to a full day. Additionally, the significant decline in barriers adherence efficacy among participants in both conditions may reflect an unrealistic degree of optimism about the ability to overcome the barriers to exercise that are present at baseline among sedentary volunteers. Actual participation may cause participants' confidence to decrease to a lower, but potentially more realistic, level. We plan to explore this finding further in future quantitative and qualitative work.

It is important to note that the findings that we report here were obtained under ideal dissemination circumstances. We were able to monitor instructors and classes reasonably closely because instructors were employed directly by the study team and sites were clustered in a relatively small geographic area. This proximity enabled us to provide regular feedback to instructors during the program, and at the beginning and end of each iteration. These training sessions provided structured opportunities to discuss and correct problems that arose, share lessons learned, and to serve as boosters to reiterate core components, goals, and objectives of the Fit and Strong! program. Monitoring instructors and treatment fidelity will be more challenging when disseminating Fit and Strong! across the country.

Despite these limitations, we conclude that these results of no differences by group on the outcomes tested are strongly positive findings. PT input into the program design and initial implementation was critically important in fostering the efficacy and safety of the program for older adults with lower-extremity OA, but the transition to using CEIs is beneficial for community translation. Fit and Strong! is less expensive to provide using CEIs (∼$20/hour for CEIs versus ∼$45/hour for PTs) and these instructors are more likely to be available, especially in rural and underserved urban areas. We look forward to other opportunities to examine further adaptations to Fit and Strong! with older adults in other parts of the country in the future.


All authors were involved in drafting the article or revising it critically for important intellectual content, and all authors approved the final version to be submitted for publication. Dr. Seymour had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study conception and design. Seymour, Hughes, Campbell, Huber.

Acquisition of data. Seymour, Hughes, Desai.

Analysis and interpretation of data. Seymour, Hughes, Campbell.


The authors thank the many participants who took part in the study. We also acknowledge the involvement and significant contribution of the following organizations and individuals: the Chicago Department of Senior Services, the Greater Chicago Chapter of the Arthritis Foundation, the National Arthritis Foundation, and the University of Illinois Chicago Survey Research Lab.