On days participants plan to exercise, morning and evening goal sessions ask them to provide an activity goal for the day; create a concrete plan; prompt them to anticipate barriers and brainstorm solutions; and reflect on whether they were able to meet this goal. Affect-based goals ask participants to engage in either a type or context of physical activity that allows them to experience positive affect. Goals focused on context are randomly generated to suggest that the participant performs activity in a place, in a social situation, or while listening to something that makes them feel good. For each condition, the Fitbit Versa device will feature a custom watch face with a clock (current local time), the date, current device battery levels, and an exercise button. The exercise button can be pressed whenever a subject wants to engage in physical activity, and provides real-time feedback on exercise duration while featuring a "smiley face" emoticon.

The TYPE/CONTEXT enhancement will augment affect-based treatment effects by additionally providing tailored recommendations for activity types and contexts that satisfy personally important psychological needs as rated by each participant at baseline. Ratings from a crowdsourced panel of adults on Amazon Mechanical Turk were used to determine the potential for specific activity types and contexts to satisfy psychological needs; our tailoring algorithm recommends the corresponding activity type or context while accounting for reported constraints. Different psychological needs will be selected each day. Tailored recommendations are incorporated immediately following the morning goal module.

The SAVOR enhancement will augment affect-based treatment effects by additionally implementing a brief savoring exercise on the smartphone during the evening goal session (after the self-monitoring module). Participants will respond to questions that are intended to enhance and prolong positive experiences during physical activity. To trigger attentional deployment, a common savoring strategy that involves intensifying experiences by focusing on them, participants will answer open-ended prompts. These prompts are drawn from a prompt pool with slightly varied wording to promote a sense of novelty.

The degree of accessibility of the daily goal sessions and fitbit interface for the study will also be assessed in the exit interview. Specifically, participants are asked a series of questions about whether they were able to read, understand, and select answers for Fitbit watch face surveys and use the exercise settings. They are also asked if they were able to red and understand the daily goal sessions on their phone. The go/no-go criterion is that at least 51% of participants respond affirmatively for each facet.

Participants are asked to indicate whether they have any constraints limiting their engagement in specific physical activity types or contexts as part of the baseline questionnaire. They also rate the relative importance of each of the psychological needs to them personally at baseline. For participants who receive the TYPE/CONTEXT enhancement with the affect-based goals, an algorithm produces physical activity recommendations based on their psychological needs that also considers their reported constraints. During the exit interview, participants in this group are asked whether they were able to follow the physical activity recommendations. The go/no-go criterion is that there is no pattern between the number of constraints reported at baseline and participants' reported ability to follow activity recommendations; therefore, we qualitatively compared the mean percentage of recommendations that participants could follow across constraint quartiles.

During the exit interview, participants who received the SAVOR enhancement with the affect-based goals will be asked whether they were generally able to understand and follow the savoring questions they received. The go/no-go criterion for accessibility is that ≥51% of participants reported being able to understand and follow the savoring questions.

Event-contingent surveys are triggered when Fitbit sensors detect physical activity via sufficiently-elevated 10-min rolling average heart rate (i.e., 55 to 60% of age-adjusted heart rate maximum). Using Fitabase data exports, the investigators will determine the percentage of correctly triggered surveys. The go/no-go criterion is that the auto-detection algorithm for physical activity correctly triggers event-contingent surveys ≥51% of the time.

This benchmark determines if the level of burden for research staff is sustainable/feasible related to Fitbit technological and connectivity issues. Staff track Fitbit inventory and document technical difficulties that require a replacement device, as well as record all instances where they have to remind participants to sync the data in their Fitbit app due to > 48 h elapsing without data reaching Fitabase servers. Go/no-go criteria are that, over the course of the study, < 25% of participants need a replacement Fitbit due to technological issues and < 25% of participants are sent repeated (i.e., >1) reminders to sync their data.

The Delighted-Terrible Scale was used to assess how participants felt about the study's Fitbit and smartphone functions in the post-study questionnaire. Items asked how they felt about the Fitbit smartwatch exercise settings, notifications to complete surveys, and survey frequency and length (i.e., burden); as well as how they felt about the smartphone-based daily goal sessions and Fitbit app. Response options are: feeling delighted (7), pleased (6), mostly satisfied (5), mixed- about equally satisfied and dissatisfied (4), mostly dissatisfied (3), unhappy (2), terrible (1) -- OR -- neutral- neither satisfied nor dissatisfied (a), or never thought about it (b). The go/no-go criterion is that <70% of participants report feeling dissatisfied (considered to be a score of 1, 2, or 3) with any of the items.

During the post-study questionnaire, participants who received recommendations for the specific types or contexts of physical activity to do (i.e., were in the affect-based goals + TYPE/CONTEXT or affect-based goals + TYPE/CONTEXT + SAVOR groups) will complete the Delighted-Terrible Scale. They are asked how they felt about the physical activity type/context recommendations they received. Response options are feeling delighted (7), pleased (6), mostly satisfied (5), mixed- about equally satisfied and dissatisfied (4), mostly dissatisfied (3), unhappy (2), terrible (1) -- OR -- neutral- neither satisfied nor dissatisfied (a), or never thought about it (b). The go/no-go criterion is that <70% of participants report feeling dissatisfied (score of 1 to 3) with physical activity recommendations.

During the post-study questionnaire, participants in the affect-based goals + SAVOR or affect-based goals + TYPE/CONTEXT + SAVOR groups will complete the validated Delighted-Terrible Scale. They are asked how they felt about the savoring questions they received. Response options are: feeling delighted (7), pleased (6), mostly satisfied (5), mixed- about equally satisfied and dissatisfied (4), mostly dissatisfied (3), unhappy (2), terrible (1) -- OR -- neutral- neither satisfied nor dissatisfied (a), or never thought about it (b). The go/no-go criterion is that <70% of participants report feeling dissatisfied (score of 1 to 3) with savoring questions.

Equity was explored based on whether accessibility/usability were approximately the same between males vs. females. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

Equity was explored based on whether efficacy was approximately the same between males vs. females. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

Equity was explored based on whether accessibility/usability was approximately the same between white vs. non-white participants. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

Equity was explored based on whether efficacy was approximately the same between white vs. non-white participants. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

Equity was explored based on whether accessibility/usability was approximately the same between Hispanic vs. non-Hispanic participants. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

Equity was explored based on whether efficacy was approximately the same between Hispanic vs. non-Hispanic participants. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

Equity was explored based on whether accessibility/usability was approximately the same between various income categories. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

Equity was explored based on whether efficacy was approximately the same between various income categories. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

Equity was explored based on whether accessibility/usability was approximately the same between age quartiles. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

Equity was explored based on whether efficacy was approximately the same between age quartiles. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

Equity was explored based on whether accessibility/usability was approximately the same between participants with overweight vs. obesity. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

Equity was explored based on whether efficacy was approximately the same between participants with overweight vs. obesity. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

Equity was explored based on whether accessibility/usability was approximately the same between mobility quartiles. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

Equity was explored based on whether efficacy was approximately the same between mobility quartiles. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

Equity was explored based on whether accessibility/usability was approximately the same between physical constraint tertiles. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

Equity was explored based on whether efficacy was approximately the same between physical constraint categories. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

Participants receive affect-based goals for two weeks. In addition to the standard mHealth intervention, participants engage in the TYPE/CONTEXT enhancement to augment the treatment effects of the affect-based goals condition.

Affect-Based Goals: On days participants plan to exercise, they engage in affect-based goal-setting sessions. Participants are asked to engage in a type or context of physical activity that allows them to experience positive affect.

TYPE/CONTEXT Enhancement: The TYPE/CONTEXT enhancement will augment affect-based treatment effects by additionally providing tailored recommendations for activity types and contexts that satisfy personally important psychological needs as rated by each participant at baseline. Ratings from a crowdsourced panel of adults on Amazon Mechanical Turk were used to determine the potential for specific activity types and contexts to satisfy psychological needs; our tailoring algorithm recommends the corresponding activity type or context while accounting for reported constraints. Different psychological needs will be selected each day. Tailored recommendations are incorporated immediately following the morning goal module.

Participants receive affect-based goals for two weeks. In addition to the standard mHealth intervention, participants engage in the SAVOR enhancement to augment the treatment effects of the affect-based goals condition.

Affect-Based Goals: On days participants plan to exercise, they engage in affect-based goal-setting sessions. Participants are asked to engage in a type or context of physical activity that allows them to experience positive affect.

SAVOR Enhancement: The SAVOR enhancement will augment affect-based treatment effects by additionally implementing a brief savoring exercise on the smartphone during the evening goal session (after the self-monitoring module). Participants will respond to questions that are intended to enhance and prolong positive experiences during physical activity. To trigger attentional deployment, a common savoring strategy that involves intensifying experiences by focusing on them, participants will answer open-ended prompts. These prompts are drawn from a prompt pool with slightly varied wording to promote a sense of novelty.

Participants receive affect-based goals for two weeks. In addition to the standard mHealth intervention, participants engage in the TYPE/CONTEXT and SAVOR enhancements to augment the treatment effects of the affect-based goals condition.

Affect-Based Goals: On days participants plan to exercise, they engage in affect-based goal-setting sessions. Participants are asked to engage in a type or context of physical activity that allows them to experience positive affect.

TYPE/CONTEXT Enhancement: The TYPE/CONTEXT enhancement will augment affect-based treatment effects via tailored recommendations for activity types and contexts that satisfy personally important psychological needs as rated by each participant at baseline (see full description in previous groups)

SAVOR Enhancement: The SAVOR enhancement will augment affect-based treatment effects by additionally implementing a brief savoring exercise on the smartphone during the evening goal session (after the self-monitoring module) (see full description in previous groups).

Total of all reporting groups

Participants receive affect-based goals for two weeks. In addition to the standard mHealth intervention, participants engage in the TYPE/CONTEXT enhancement to augment the treatment effects of the affect-based goals condition.

Affect-Based Goals: On days participants plan to exercise, they engage in affect-based goal-setting sessions. Participants are asked to engage in a type or context of physical activity that allows them to experience positive affect.

TYPE/CONTEXT Enhancement: The TYPE/CONTEXT enhancement will augment affect-based treatment effects by additionally providing tailored recommendations for activity types and contexts that satisfy personally important psychological needs as rated by each participant at baseline. Ratings from a crowdsourced panel of adults on Amazon Mechanical Turk were used to determine the potential for specific activity types and contexts to satisfy psychological needs; our tailoring algorithm recommends the corresponding activity type or context while accounting for reported constraints. Different psychological needs will be selected each day. Tailored recommendations are incorporated immediately following the morning goal module.

Participants receive affect-based goals for two weeks. In addition to the standard mHealth intervention, participants engage in the SAVOR enhancement to augment the treatment effects of the affect-based goals condition.

Affect-Based Goals: On days participants plan to exercise, they engage in affect-based goal-setting sessions. Participants are asked to engage in a type or context of physical activity that allows them to experience positive affect.

SAVOR Enhancement: The SAVOR enhancement will augment affect-based treatment effects by additionally implementing a brief savoring exercise on the smartphone during the evening goal session (after the self-monitoring module). Participants will respond to questions that are intended to enhance and prolong positive experiences during physical activity. To trigger attentional deployment, a common savoring strategy that involves intensifying experiences by focusing on them, participants will answer open-ended prompts. These prompts are drawn from a prompt pool with slightly varied wording to promote a sense of novelty.

Participants receive affect-based goals for two weeks. In addition to the standard mHealth intervention, participants engage in the TYPE/CONTEXT and SAVOR enhancements to augment the treatment effects of the affect-based goals condition.

Affect-Based Goals: On days participants plan to exercise, they engage in affect-based goal-setting sessions. Participants are asked to engage in a type or context of physical activity that allows them to experience positive affect.

TYPE/CONTEXT Enhancement: The TYPE/CONTEXT enhancement will augment affect-based treatment effects via tailored recommendations for activity types and contexts that satisfy personally important psychological needs as rated by each participant at baseline (see full description in previous groups)

SAVOR Enhancement: The SAVOR enhancement will augment affect-based treatment effects by additionally implementing a brief savoring exercise on the smartphone during the evening goal session (after the self-monitoring module) (see full description in previous groups).

During the exit interview, participants compare their experience with physical activity before and after participation in the eMOTION Study and are asked if they personally feel as if the degree of enjoyment they feel while engaging in physical activity changed or stayed the same. The percentage of participants responding affirmatively will be calculated. The "go/no-go criterion" is that ≥51% of participants in the affect-based conditions report a perceived increase in enjoyment of physical activity.

This analysis explored whether participants who received affect-based goals (regardless of the specific TYPE/CONTEXT and/or SAVOR enhancements included) reported increased enjoyment. The three affect-based arms (affect + TYPE/CONTEXT [n=9], affect + SAVOR [n=9], affect + TYPE/CONTEXT + SAVOR [n=9]) were therefore considered to be a single collapsed sub-sample (n=27). This is because we did not have a large enough sample size to compare between the four groups.

In the Post-Study Questionnaire, participants will rate the usability of the eMOTION Study's daily goal sessions and Fitbit Versa protocol via the System Usability Scale (SUS). The SUS has 10 items, and participants indicate their degree of agreement with each statement on a 5-point Likert scale ranging from "strongly disagree" (1) to "strongly agree" (5). The SUS is then scored by summing across items (all items are first rescored to a 0 to 4 scale, and even items are reverse-scored before summing) and then multiplying the sum by 2.5. The study's go/no-go criterion is that both the daily goal sessions and Fitbit protocols receive at least an average score (≥68) on the SUS.

The study protocol and statistical analysis plan pre-specified that treatment arms would be assessed in a combined manner (i.e, as a full sample). This analysis explored the basic usability of the primary components (i.e., daily goal sessions, Fitbit Versa) used to deliver the eMOTION Study intervention, which were kept uniform for all participants, regardless of treatment arm (i.e., intensity-based goals, affect + TYPE/CONTEXT, affect + SAVOR, affect + TYPE/CONTEXT + SAVOR).

The degree of accessibility of the daily goal sessions and fitbit interface for the study will also be assessed in the exit interview. Specifically, participants are asked a series of questions about whether they were able to read, understand, and select answers for Fitbit watch face surveys and use the exercise settings. They are also asked if they were able to red and understand the daily goal sessions on their phone. The go/no-go criterion is that at least 51% of participants respond affirmatively for each facet.

The study protocol and statistical analysis plan pre-specified that treatment arms would be assessed in a combined manner (i.e, as a full sample). This analysis explored the basic accessibility/usability of the primary components (i.e., daily goal sessions, Fitbit Versa) used to deliver the eMOTION Study intervention, which were kept uniform for all participants, regardless of treatment arm (i.e., intensity-based goals, affect + TYPE/CONTEXT, affect + SAVOR, affect + TYPE/CONTEXT + SAVOR).

Participants are asked to indicate whether they have any constraints limiting their engagement in specific physical activity types or contexts as part of the baseline questionnaire. They also rate the relative importance of each of the psychological needs to them personally at baseline. For participants who receive the TYPE/CONTEXT enhancement with the affect-based goals, an algorithm produces physical activity recommendations based on their psychological needs that also considers their reported constraints. During the exit interview, participants in this group are asked whether they were able to follow the physical activity recommendations. The go/no-go criterion is that there is no pattern between the number of constraints reported at baseline and participants' reported ability to follow activity recommendations; therefore, we qualitatively compared the mean percentage of recommendations that participants could follow across constraint quartiles.

This analysis only applied to participants who received TYPE/CONTEXT recommendations. The two TYPE/CONTEXT arms (i.e., affect-based goals + TYPE/CONTEXT, affect-based goals + TYPE/CONTEXT + SAVOR) were combined and considered as a single sub-sample (N=18), since both received identical TYPE/CONTEXT treatment components. n=3 of these participants did not remember receiving TYPE/CONTEXT recommendations, so they were excluded from the analysis.

During the exit interview, participants who received the SAVOR enhancement with the affect-based goals will be asked whether they were generally able to understand and follow the savoring questions they received. The go/no-go criterion for accessibility is that ≥51% of participants reported being able to understand and follow the savoring questions.

This analysis only applied to participants who received savoring exercises. The two SAVOR arms (i.e., affect-based goals + SAVOR, affect-based goals + TYPE/CONTEXT + SAVOR) were combined and considered as a single sub-sample (N=18), since both received identical SAVOR treatment components. n=4 of these participants did not remember receiving savoring exercises, so they were excluded from the analysis.

Event-contingent surveys are triggered when Fitbit sensors detect physical activity via sufficiently-elevated 10-min rolling average heart rate (i.e., 55 to 60% of age-adjusted heart rate maximum). Using Fitabase data exports, the investigators will determine the percentage of correctly triggered surveys. The go/no-go criterion is that the auto-detection algorithm for physical activity correctly triggers event-contingent surveys ≥51% of the time.

The study protocol and statistical analysis plan pre-specified that treatment arms would be assessed in a combined manner (i.e, as a full sample). The physical activity auto-detection algorithm was applied uniformly across all participants (N=36), regardless of treatment arm. The number of correctly-triggered surveys were divided by the total number of event-contingent surveys sent during the study (i.e., N=1555) in this analysis.

This benchmark determines if the level of burden for research staff is sustainable/feasible related to Fitbit technological and connectivity issues. Staff track Fitbit inventory and document technical difficulties that require a replacement device, as well as record all instances where they have to remind participants to sync the data in their Fitbit app due to > 48 h elapsing without data reaching Fitabase servers. Go/no-go criteria are that, over the course of the study, < 25% of participants need a replacement Fitbit due to technological issues and < 25% of participants are sent repeated (i.e., >1) reminders to sync their data.

The study protocol and statistical analysis plan pre-specified that treatment arms would be assessed in a combined manner (i.e, as a full sample). This analysis focused on the basic sustainability/feasibility of Fitbit-related issues for study staff. Because all participants received Fitbit smartwatches that underwent uniform technological setup and connectivity procedures, each participant's treatment arm was irrelevant.

The Delighted-Terrible Scale was used to assess how participants felt about the study's Fitbit and smartphone functions in the post-study questionnaire. Items asked how they felt about the Fitbit smartwatch exercise settings, notifications to complete surveys, and survey frequency and length (i.e., burden); as well as how they felt about the smartphone-based daily goal sessions and Fitbit app. Response options are: feeling delighted (7), pleased (6), mostly satisfied (5), mixed- about equally satisfied and dissatisfied (4), mostly dissatisfied (3), unhappy (2), terrible (1) -- OR -- neutral- neither satisfied nor dissatisfied (a), or never thought about it (b). The go/no-go criterion is that <70% of participants report feeling dissatisfied (considered to be a score of 1, 2, or 3) with any of the items.

The study protocol and statistical analysis plan pre-specified that treatment arms would be assessed in a combined manner (i.e, as a full sample). All participants engaged with the most basic Fitbit and smartphone-based components in the same way, regardless of their treatment arms. All items asked about study elements that were kept uniform across participants.

During the post-study questionnaire, participants who received recommendations for the specific types or contexts of physical activity to do (i.e., were in the affect-based goals + TYPE/CONTEXT or affect-based goals + TYPE/CONTEXT + SAVOR groups) will complete the Delighted-Terrible Scale. They are asked how they felt about the physical activity type/context recommendations they received. Response options are feeling delighted (7), pleased (6), mostly satisfied (5), mixed- about equally satisfied and dissatisfied (4), mostly dissatisfied (3), unhappy (2), terrible (1) -- OR -- neutral- neither satisfied nor dissatisfied (a), or never thought about it (b). The go/no-go criterion is that <70% of participants report feeling dissatisfied (score of 1 to 3) with physical activity recommendations.

This analysis only applied to participants who received TYPE/CONTEXT recommendations. The two TYPE/CONTEXT arms (i.e., affect-based goals + TYPE/CONTEXT, affect-based goals + TYPE/CONTEXT + SAVOR) were combined and considered as a single sub-sample (N=18), since both received identical TYPE/CONTEXT treatment components. Of these participants, n=3 did not remember receiving TYPE/CONTEXT recommendations, and an additional n=2 failed to respond, so they were excluded from the analysis.

During the post-study questionnaire, participants in the affect-based goals + SAVOR or affect-based goals + TYPE/CONTEXT + SAVOR groups will complete the validated Delighted-Terrible Scale. They are asked how they felt about the savoring questions they received. Response options are: feeling delighted (7), pleased (6), mostly satisfied (5), mixed- about equally satisfied and dissatisfied (4), mostly dissatisfied (3), unhappy (2), terrible (1) -- OR -- neutral- neither satisfied nor dissatisfied (a), or never thought about it (b). The go/no-go criterion is that <70% of participants report feeling dissatisfied (score of 1 to 3) with savoring questions.

This analysis only applied to participants who received SAVOR questions. The two SAVOR arms (i.e., affect-based goals + SAVOR, affect-based goals + TYPE/CONTEXT + SAVOR) were combined and considered as a single sub-sample (N=18), since both received identical SAVOR treatment components. Of these participants, n=4 did not remember receiving TYPE/CONTEXT recommendations, and an additional n=2 did not respond, so they were excluded from the analysis.

Equity was explored based on whether accessibility/usability were approximately the same between males vs. females. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to sex-at-birth (male vs. female), regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample (N=36) were split into two sub-groups based on sex.

Equity was explored based on whether efficacy was approximately the same between males vs. females. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to sex-at-birth (male vs. female), regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample (N=36) were split into two sub-groups based on sex.

Equity was explored based on whether accessibility/usability was approximately the same between white vs. non-white participants. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to race (white vs. non-white), regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into two sub-groups based on race.

Equity was explored based on whether efficacy was approximately the same between white vs. non-white participants. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to race (white vs. non-white), regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into two sub-groups based on race.

Equity was explored based on whether accessibility/usability was approximately the same between Hispanic vs. non-Hispanic participants. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to ethnicity (Hispanic vs. non-Hispanic), regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into two sub-groups based on ethnicity.

Equity was explored based on whether efficacy was approximately the same between Hispanic vs. non-Hispanic participants. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to ethnicity (Hispanic vs. non-Hispanic), regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into two sub-groups based on ethnicity.

Equity was explored based on whether accessibility/usability was approximately the same between various income categories. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to annual income, regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into five sub-groups based on income.

Equity was explored based on whether efficacy was approximately the same between various income categories. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to annual income, regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into five sub-groups based on income.

Equity was explored based on whether accessibility/usability was approximately the same between age quartiles. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to age, regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into four quartiles based on age.

Equity was explored based on whether efficacy was approximately the same between age quartiles. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to age, regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into four quartiles based on age.

Equity was explored based on whether accessibility/usability was approximately the same between participants with overweight vs. obesity. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to BMI status (overweight vs. obese), regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into two sub-groups based on BMI status.

Equity was explored based on whether efficacy was approximately the same between participants with overweight vs. obesity. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to BMI status (overweight vs. obese), regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into two sub-groups based on BMI status.

Equity was explored based on whether accessibility/usability was approximately the same between mobility quartiles. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to mobility, regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into four quartiles based on mobility.

Equity was explored based on whether efficacy was approximately the same between mobility quartiles. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to mobility, regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into four quartiles based on mobility.

Equity was explored based on whether accessibility/usability was approximately the same between physical constraint tertiles. The percentage of participants who rated the daily goal sessions and Fitbit protocol as sufficiently accessible/usable (i.e., scored the daily goal sessions and Fitbit protocol at-or-above the System Usability Scale's validated cutoff of 68) were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to physical constraints, regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into three tertiles based on physical constraints.

Equity was explored based on whether efficacy was approximately the same between physical constraint categories. The percentage of participants who reported experiencing (i.e., efficacious) or not experiencing (i.e., not efficacious) an increase in enjoyment for physical activity during the study were calculated.

This analysis was concerned with the basic equity of the eMOTION Study intervention related to physical constraints, regardless of the specific treatment arm that participants were in. Therefore, participants from the full sample were split into three tertiles based on physical constraints.

Participants receive affect-based goals for two weeks. In addition to the standard mHealth intervention, participants engage in the TYPE/CONTEXT enhancement to augment the treatment effects of the affect-based goals condition.

Affect-Based Goals: On days participants plan to exercise, they engage in affect-based goal-setting sessions. Participants are asked to engage in a type or context of physical activity that allows them to experience positive affect.

TYPE/CONTEXT Enhancement: The TYPE/CONTEXT enhancement will augment affect-based treatment effects by additionally providing tailored recommendations for activity types and contexts that satisfy personally important psychological needs as rated by each participant at baseline. Ratings from a crowdsourced panel of adults on Amazon Mechanical Turk were used to determine the potential for specific activity types and contexts to satisfy psychological needs; our tailoring algorithm recommends the corresponding activity type or context while accounting for reported constraints. Different psychological needs will be selected each day. Tailored recommendations are incorporated immediately following the morning goal module.

Participants receive affect-based goals for two weeks. In addition to the standard mHealth intervention, participants engage in the SAVOR enhancement to augment the treatment effects of the affect-based goals condition.

Affect-Based Goals: On days participants plan to exercise, they engage in affect-based goal-setting sessions. Participants are asked to engage in a type or context of physical activity that allows them to experience positive affect.

SAVOR Enhancement: The SAVOR enhancement will augment affect-based treatment effects by additionally implementing a brief savoring exercise on the smartphone during the evening goal session (after the self-monitoring module). Participants will respond to questions that are intended to enhance and prolong positive experiences during physical activity. To trigger attentional deployment, a common savoring strategy that involves intensifying experiences by focusing on them, participants will answer open-ended prompts. These prompts are drawn from a prompt pool with slightly varied wording to promote a sense of novelty.

Participants receive affect-based goals for two weeks. In addition to the standard mHealth intervention, participants engage in the TYPE/CONTEXT and SAVOR enhancements to augment the treatment effects of the affect-based goals condition.

Affect-Based Goals: On days participants plan to exercise, they engage in affect-based goal-setting sessions. Participants are asked to engage in a type or context of physical activity that allows them to experience positive affect.

TYPE/CONTEXT Enhancement: The TYPE/CONTEXT enhancement will augment affect-based treatment effects via tailored recommendations for activity types and contexts that satisfy personally important psychological needs as rated by each participant at baseline (see full description in previous groups) SAVOR Enhancement: The SAVOR enhancement will augment affect-based treatment effects by additionally implementing a brief savoring exercise on the smartphone during the evening goal session (after the self-monitoring module) (see full description in previous groups).