This 6-month randomized controlled trial tested the relative efficacy of an enhanced versus original evidence- and theory-based, Spanish-language PA intervention website on changes in MVPA at the end of the active intervention period (6 mo). The study was conducted at Brown University and registered as a clinical trial (NCT03491592).

All study procedures were approved by the Brown University Institutional Review Board (IRB#: 00000556) and described in detail in a prior report [21]. All participants provided written informed consent.

Participants included those who self-identified as female and Latina. For inclusion, participants were required to be aged 18-65 years, and engaging in less than 60 minutes per week of self-reported leisure-time MVPA. To be eligible, participants needed to score more than 16 on the Short Test of Functional Health Literacy in Adults, to determine whether participants have adequate literacy levels to read study materials in Spanish [23-25]. This measure has high internal validity (>0.95 in either language) and strong positive associations with education. Additional eligibility criteria included regular access to text-message compatible and internet-connected devices through home, work, or their community. Exclusion criteria included any serious medical condition that could make unsupervised PA unsafe (based on the modified Physical Activity Readiness Questionnaire) [26], including a history of coronary heart disease (history of myocardial infarction or symptoms of angina), stroke, or orthopedic conditions which limit mobility; other exclusion criteria were hospitalization due to a psychiatric disorder in the past 3 years, BMI above 45 kg/m², current or planned pregnancy, or moving from the area within this study’s time frame.

We assessed potential between-group differences in baseline characteristics (demographics and activity level) using graphical methods, t tests for continuous variables, and χ² tests for categorical variables. We examined the effects of the enhanced versus the original intervention at the end of the active intervention period on our primary outcome: minutes per week of objectively measured MVPA at 6 months using a generalized linear model with the identity link function. We controlled for the baseline value of the outcome, accelerometer wear time as well as a time-varying indicator of before vs during pandemic time). A similar series of regression models assessed between-group differences in the secondary outcome (self-reported MVPA). For all analyses involving self-reported MVPA, the total amount of weekly PA reported was based on all types of activity, thus including leisure, occupational, transport, and housework categories of MVPA.

As a subsequent step, given the high proportion of participants who were inactive at baseline (0 min/wk of self-reported MVPA), we examined the potential conditional effects of the intervention as a function of baseline activity level (dichotomized as inactive vs not). Effects were examined using similar models to those described previously: a generalized linear model that included the main effects of intervention (enhanced vs original), the potential moderator (indicator of being inactive at baseline), as well as the interaction between the two. Evidence of moderation exists if the coefficient of the interaction term is statistically different than zero. To assess whether the differences in the effects of treatment were a function of the amount of activity being reported, we ran a similar set of models with a continuous moderator (min/wk of MVPA at baseline), as opposed to the dichotomous version (no activity vs at least some). Analyses were performed with self-reported MVPA as the moderating variable and with accelerometer-measured MVPA as the moderating variable (continuous and dichotomous).

Next, using a generalized linear model, we examined the effects of the intervention on the proportion of participants meeting national PA guidelines for aerobic activity (defined as at least 150 min/wk of MVPA) at 6 months, measured by an accelerometer-based device. Models specified a logit link function and estimated odds ratios (OR and corresponding 95% CIs) as measures of effect. Models were run first, only specifying the main effect of treatment assignment (original vs enhanced intervention) and then conditional on baseline PA (inactive vs not).

All analyses were based on the intent to treat the sample, with all randomized participants included in the analysis. Details about power analyses conducted to determine the sample size are reported elsewhere [21]. Generalized linear models use a quasi-likelihood-based approach to estimation thus making use of all available data (intent-to-treat sample) without directly imputing missing values. Analyses were run in SAS (version 9.4; SAS Institute Inc) with a significance level set at 5% a priori.

A full description of this study sample is presented in Table 1. The final sample included 195 participants randomized to the original PA intervention (n=92) or the enhanced intervention at baseline (n=103). Overall, participants were aged 43.31 (SD 10.29) years on average, predominantly Dominican (n=80 or 41%), 97.5% (n=190) of participants were first generation, with 62.4% (n=122) participants reporting at least a high school level education. Of note, 68.7% (n=134) of participants were inactive at baseline. There were no differences between intervention conditions at baseline for sociodemographic variables or PA level (P>.05). The flow of participants who were assessed for eligibility, randomized, and who attended follow-up visits are depicted in the CONSORT diagram (Figure 1). In the diagram, “completed” indicates those who attended the 6-month measurement visit and have data for the 7-day PAR. At 6 months, 133 participants completed the accelerometer-based device measurements, with no differences between conditions.

Mean minutes per week of accelerometer-measured MVPA increased significantly in both groups, from 19.70 (SD 47.93, median 0) at baseline to 46.90 (SD 66.24, median 19.00) at 6 months among enhanced participants compared to 20.57 (SD 42.69, median 0) to 42.87 (SD 78.18, median 0) among those randomized to the original intervention. An adjusted model (adjusting for baseline MVPA and accelerometer wear time) did not indicate significant between-group differences at 6 months (P=.78).

The 7-day PAR interview findings were similar. Participants in the enhanced intervention condition increased self-reported MVPA from 57.88 (SD 260.25, median 0) minutes per week at baseline to 114.97 (SD 119.63, median 75) compared to the original intervention who reported an increase from 55.19 (SD 149.12, median 0) to 87.88 (SD 115.22, median 52). There were no differences between intervention conditions by self-reported MVPA at 6 months (P=.13). Thus, there was a significant increase from baseline to 6 months in MVPA in both groups, but this increase was not significantly different between treatment arms for either self-report or accelerometer-measured PA.

We found a moderating effect of self-reported baseline PA (inactive vs not) on both accelerometer-measured and self-reported MVPA at 6 months (controlling for baseline). For inactive participants, all participants reported 0 total minutes of self-reported MVPA at baseline.

For low-active participants, the median baseline level of MVPA was 48 minutes per week, with 25% (n=49) of the sample reporting 20 minutes per week or less. Among inactive participants, there was no significant effect of the enhanced intervention compared to the original intervention on self-reported MVPA (b=7.10; SE 22.79; P=.75). For those reporting some activity at baseline (low-active), significant effects were detected which favored the enhanced intervention (b=72.51; SE 27.91; P=.01). Similar findings were seen with accelerometer-measured MVPA, with significant effects of the enhanced intervention among those who reported at least some activity at baseline (b=21.51; SE 8.32; P=.02). Moderating effects were not detected based on the amount of activity being done at baseline (that is, the number of minutes), only on whether participants did some versus none (see Figure 2). There were no moderating effects of minutes per week of MVPA at baseline, suggesting intervention effects were not conditional on the quantity of PA at baseline, but just whether or not any was being completed. The findings were nearly identical when we examined the moderating variable of inactive versus low-active with accelerometer-measured MVPA, and the 6-month MVPA outcomes were self-reported or accelerometer-measured.

Looking across all participants, 30% (n=31) of participants in the enhanced intervention condition met national PA guidelines for aerobic activity at 6 months based on self-reported data, compared to 21% (n=19) of original intervention (OR 1.75, 95% CI 0.87-3.55). No participants met aerobic PA guidelines at baseline in either condition. Much like the continuous outcome for self-reported MVPA, for low-active participants, 45% (n=46) of participants in the enhanced intervention met national PA guidelines at 6 months compared to 20% (n=18) of original intervention participants (OR 3.29, 95% CI 1.05-11.31). For those who were inactive at baseline, there was no difference between arms in meeting national guidelines (n=25 vs n=19, 24% vs 21%) for enhanced versus original intervention (OR 1.28, 95% CI 0.54-3.06).

The objective of this paper was to evaluate whether the enhanced Pasos Hacia La Salud II intervention significantly increased PA, and helped more Latina women meet PA guidelines within 6 months, compared to the original intervention (Pasos I). The primary goal of this study was to evaluate whether there was a difference between the intervention conditions at reaching our primary end point: meeting national PA guidelines at 6 months. Overall, the results of this study indicate that both the enhanced and original intervention conditions helped Latina women increase their PA during the 6-month intervention. Both arms of the intervention appeared equally effective, with a significant increase in PA from baseline, yet there were no significant differences between groups in overall changes in minutes of activity or in meeting national guidelines.

However, the findings indicated that meeting aerobic PA guidelines and increasing PA differed for those participants who started the program engaging in some amount of MVPA at baseline, compared to those who started with no MVPA. For participants doing even a small amount of MVPA at baseline, the enhanced intervention was more effective at increasing the mean number of minutes per week of MVPA from baseline through 6 months, compared to the original condition. For those doing no activity at baseline, however, there were no differences in the intervention effects by treatment condition. Furthermore, the enhanced intervention resulted in more participants reaching the national aerobic PA guidelines within 6 months than the original intervention, only among low-active participants (ie, those who were doing some activity at baseline). Notably, this moderator effect was seen only for the dichotomous outcome (some vs no activity), not for baseline activity as a continuous outcome, suggesting an important difference between those who were doing some amount of MVPA albeit small (ie, 25-50 min/wk)—compared to those who had not yet begun to engage in any MVPA.

For the overall main effects, the findings are comparable to the original intervention study, which was conducted among a geographically and culturally different population of Latina women. In Pasos I, the participants were predominantly Mexican American (84.4%), and first-generation Americans (81.9%) recruited from the San Diego, California, area [14], whereas in Pasos II the participants were predominantly Dominican recruited from the Providence, Rhode Island, area and 97.5% were first generation. Despite differences in this study’s settings and study participants, in both settings, the original intervention increased minutes of PA at 6 months. In Pasos I, intervention participants increased their self-reported MVPA from 8 minutes per week to over 100 minutes per week [14], and in Pasos II, participants receiving the same intervention as those in Pasos I increased their self-reported PA from an average of 55 (SD 262.07) minutes at baseline to more than 85 minutes per week, and the enhanced intervention participants increased from 57 minutes at baseline to more than 114 minutes at 6 months. Future research can examine statistical comparisons of these 2 samples through integrative data analysis, which is beyond the scope of this paper. Of note, the intervention evaluated in both of these trials indicates generalizable efficacy for increasing MVPA in Latina women, in 2 different samples of Latina women, in 2 geographically different regions.

Few other studies have been conducted that evaluate the effects of a culturally tailored, technology-delivered PA intervention for Latina women. In a systematic review of culturally tailored, technology-delivered interventions for changing health behaviors, there is mixed support across health behaviors to recommend culturally adapting technology-delivered interventions [38]. Notably, for PA behavior, there is a small but significant effect that favors culturally tailored PA interventions from 5 previous randomized controlled trials. This review included the efficacy trial which tested the original Pasos intervention, and the addition of this study’s findings support the evidence in favor of a culturally tailored PA intervention for Latina women [38]. Additional studies evaluating PA interventions tailored to the Latino population detect similar results. For example, a previous study examined the effects of a PA intervention for Latina women in faith-based organizations. This study identified a marginal increase in self-reported MVPA and nonsignificant findings for accelerometer-measured PA behavior [39]. Although the findings are comparable, the key difference between this study and the faith-based culturally tailored PA intervention is that the latter requires substantial in-person involvement, and thus a large amount of staff time is required to implement an intensive in-person PA intervention. This difference in intervention delivery has important implications for the future scalability and dissemination of PA interventions for Latina women in real-world contexts, with constraints around staff- and participant time for in-person interventions.

The results of this study expand upon the generalizability of the findings for the original intervention by testing the effects among a geographically and culturally different population. However, the conditional effects of the enhanced intervention may not generalize to other Latina subgroups, Latino men, or other ethnic groups. For example, features specific to the enhanced arm such as the discussion board with opportunities for group meetups, text messages, and other content may not be as engaging or as motivating as it was for this group. Additionally, although the enhanced intervention added features to improve engagement with the intervention (by prompting the use of the website, and offering both audio and written versions of some materials), future research could further expand engagement with the program through the addition of infographics, video, or additional audio-based content.

While it is possible that the improvements in PA in this study could be seen as modest, with one-third of participants reaching the recommended PA levels in 6 months, it is important to note the distinction in the effects of the intervention for those who were doing any activity at all, versus those doing none. Nearly two-thirds of the sample were doing no PA at all at baseline. To motivate completely inactive individuals to become active may be the most difficult part of the behavior change process, compared to those who are low-active, which was reflected in our results. While both conditions significantly helped participants increase their minutes of MVPA per week, the intervention enhancements were most helpful for participants doing some activity at baseline, not for completely inactive participants. Specifically, the moderator findings in particular highlight that there are possibly differences in the effects of the enhanced versus original intervention for those who are contemplating change, versus those who have already started to change their MVPA behavior [22]. Previous research suggests that the underlying barrier to the stage of change progression is different for those who are in the contemplation stage (deciding whether to change) versus those who are in the preparation stage (insufficient beliefs about their abilities to successfully change) [40]. Thus, while the original intervention is known to increase self-efficacy [14], the intervention enhancements were designed to further support increases in self-efficacy, and promote engagement with the original intervention which may be 1 explanation for the moderating treatment effects. However, these enhancements may not be providing enough support in the decision-making process for inactive Latina women to become physically active. This could potentially be facilitated by using additional forms of technology.

For example, delivering the intervention via a smartphone app, wearables, or other technology-based tools may increase convenience and would enable the use of push notifications to nudge participants, which might be particularly beneficial for inactive individuals. To date, few other technology-delivered interventions have been tested that are culturally tailored to the Latina and Latino populations. Four other published studies used similar technology to Pasos I and Pasos II, using the internet, or text messages to increase MVPA [41]. Two other studies evaluated MVPA interventions specifically designed for the Latino population and used fitness wearables, or fitness-tracking mobile apps as part of the intervention [42,43]. These interventions resulted in significant increases in MVPA, and given that both were feasibility studies using smaller sample sizes, with less than 6 months follow-up [42,43], future research might evaluate whether more advanced fitness technology may help to augment the effects of the Pasos intervention. However, such interventions would likely exclude individuals without access to certain devices, including smartphones, having implications for addressing health disparities.

Lastly, this study identified changes in MVPA after 6 months, and previous MVPA interventions among Latina women have either evaluated shorter follow-up durations [41-43] or have failed to identify longer-term maintenance of intervention effects [19]. Thus, while this study identified that the enhanced intervention arm may lead to significantly greater increases in MVPA after an initial period for Latina women doing any MVPA at baseline, future research should evaluate whether (1) these findings persist beyond 6 months and (2) whether those who were inactive at baseline need either more support or more time (>6 mo) for the original or enhanced Pasos intervention to increase MVPA behavior.

The findings from this study indicate that an enhanced version of the web-delivered, individually tailored intervention for Spanish-speaking Latina women resulted in larger increases in PA compared to the original (Pasos I) intervention, but only among those who were low-active at baseline. Overall, the enhanced version of the intervention did not outperform the original version, and both versions of the intervention significantly increased MVPA in Latina women. The enhanced version of the website incorporated text messaging, contained dynamic features to encourage website use, and featured additional targeting of key theoretical constructs identified as important mechanisms of action in the prior study [14,44]. Future research should seek to better understand the extent to which additional tailoring, time, or intervention techniques may be needed for those who report doing no PA at all and seek to understand methods for the dissemination and implementation of the enhanced intervention for low-active Latina women.