Examining the feasibility and acceptability of a six-week at-home physical activity intervention with a focus on strength training for Black women: a randomized controlled trial

Abstract

Background

Physical activity (PA) is protective against many health conditions such as cardiovascular disease (CVD), obesity, and all-cause mortality. Black women have some of the highest rates of non-communicable diseases associated with a lack of PA. Most previous PA studies for Black women have focused on aerobic PA. This was one of the first studies to explore a PA program for Black women that emphasized strength training and utilized home-based methodology. The current pilot randomized controlled trial evaluated the feasibility and acceptability of an at-home strengthening physical activity intervention. The study also examined the preliminary efficacy of a physical activity intervention (PAI) on physical activity and psychosocial variables, compared to a wait-list-control (WLC) group.

Methods

Low-active Black women (< 90 min physical activity per week; n = 36; mean age = 44.0, + / 12.6) were randomized to either the six-week PAI or WLC. Participants in the PAI were sent workouts and demonstration videos weekly via email, engaged in a weekly group Zoom counseling and exercise session, and participated in a social media motivational group chat. Participants were assessed at baseline and at the conclusion of the six-week intervention. The primary outcomes of the current study are feasibility and acceptability as measured by retention and self-reported satisfaction via survey and focus groups. Additionally, descriptive statistics were obtained regarding physical activity and related psychosocial measures.

Results

Of the 36 participants who were randomized, 24 were retained at the post-intervention timepoint. The overall program had a high satisfaction rating, but feasibility thresholds were not met. Attendance at the Zoom counseling sessions was 48%. The PAI group had higher self-efficacy for physical activity, behavioral regulation for exercise, and family social support than the WLC group. The focus groups revealed positive perceptions of the program and suggestions for improvement.

Conclusions

This study provides evidence for the acceptability of the PAI. Future research with larger samples sizes should focus on building community partnerships and building authentic connections between participants.

Trial registration

This study was registered at Clinicaltrials.gov, NCT05997888 on August 18th, 2023.

Supplementary Information

The online version contains supplementary material available at https://doi.org/10.1186/s12905-026-04616-7.

Introduction

Regular participation in physical activity is linked to numerous health benefits, such as lower premature mortality and reduced risk for chronic illness such as cardiovascular disease, cancer, and hypertension [1–3]. While national rates of physical activity are low for adults, the proportion of individuals meeting physical activity guidelines are even lower among some racial and gender groups. For example, Black women reported the lowest rates of physical activity across all demographic groups [4, 5]. Black women also experience some of the highest rates of chronic disease incidence and other negative health outcomes associated with a lack of physical activity [6, 7]. Unequal access to physical activity information and safe areas to participate in physical activity, as well as unequal exposure to health risks contribute to these disparities [8]. Black women also often face challenges when trying to be physically active, such as family responsibilities, body and hair care concerns, financial strains, and environmental obstacles that impede their ability to engaged in PA [9].

Research has examined the efficacy of various intervention strategies that speak to the lived experiences of Black women to improve upon the “one size fits all” approach [5, 10, 11]. To mitigate these additional barriers, there has been an increase in research examining culturally appropriate physical activity interventions. A culturally appropriate or culturally relevant intervention is one that targets a population’s cultural characteristics, values, behaviors, lived experiences, normative beliefs and behaviors [1]. These programs utilize culturally appropriate strategies, which consider historical events and social and physical environments into the design, implementation, and appraisal of the intervention [4]. Culturally-tailored interventions for Black women that address factors such as cultural preferences for body type, social support barriers and facilitators, and environmental concerns have been efficacious for increasing lifestyle physical activity [12]. Interventions that target physical activity for Black women that consider their experiences and values are essential to the effectiveness of any proposed intervention [13, 14]. Research into interventions that use culturally-appropriate strategies to engage Black women in strengthening physical activity and maintain this behavior are currently lacking and should be investigated in more depth.

Most physical activity interventions for Black women have focused on cardiovascular activity, such as walking or dancing [4, 15–17] While light-to-moderate aerobic physical activity is essential for cardiovascular health and related outcomes, strength training is also an important factor for overall physical health [18]. Participating in regular strengthening activities can increase muscle mass, muscle strength, and improve bone density, all of which are important for health during aging and injury prevention [19]. This is particularly important for women, who experience these losses more drastically due to hormonal changes [20]. However, women reportedly engage in strength training less than men, highlighting a need for further research on interventions to improve women’s participation [20]. Additionally, more research is needed to better understand how to assist Black women to engage in strength activities for musculoskeletal longevity, while being mindful of cultural considerations to provide these benefits to bone and muscle health. Programs that incorporate strengthening exercises and take participants experiences and beliefs about physical activity into account are imperative for successful implementation. For example, traditional physical activity interventions use extensive resources with face-to-face classes and counseling that could be difficult to implement into daily life [21, 22].

There is currently not a study that examines the acceptability and feasibility of strengtheningng physical activity using culturally-appropriate strategies for low-active Black women. Strengthening physical activity may hold different perceptions by Black women and may require different strategies for intervention. The purpose of the current study was to examine the feasibility and acceptability of a six-week home-based physical activity intervention with a focus on strength training among Black women to begin to address this gap in the literature.

Methods

The current study was a randomized controlled pilot study conducted in the Midwest.

Participants were randomly assigned to a behavioral intervention (n = 18) or a wait-list control (n = 18) group, each lasting six weeks. The behavioral intervention consisted of five home-based workouts per week sent digitally, and one Zoom session per week that contained an exercise session and a group counseling session. Additionally, each week participants were sent a motivational prompt via WhatsApp and were encouraged to connect with each other about physical activity motivation, barriers, and facilitators through this app. Weekly Zoom sessions and WhatsApp motivational prompts were developed by formative focus groups prior to the intervention that asked women about values and experiences related to physical activity.

Acceptability, physical activity, and psychosocial variables of interest were measured via self-report at baseline and six weeks (post-intervention). Focus groups were conducted for all participants at the conclusion of the study to assess acceptability and feasibility of the program (see Table 1). All participants were paid $100 for their time. This study was approved by the UMN’s Institutional Review Board.

Table 1.

Measures assessed at each timepoint

Timepoint	Measures
Baseline	Demographic form, 7-Day PAR, Self-Efficacy measure, PACES, OEE, PASS, BREQ-2,
Intervention (Weeks 1–6)	FS (once weekly)
Post-intervention	Actigraph, 7-Day PAR, Self-Efficacy measure, PACES, OEE, PASS, BREQ-2,HTHM, EDS, Customer satisfaction

Participants

Participants were 36 women identifying as Black living in a Midwest metropolitan area. In order to meet inclusion criteria for the current study, participants had to: (a) identify as a woman, (b) identify as Black and/or multiracial Black, (c) be insufficiently active (< 90 min of physical activity per week (as explained by researchers as “any activity that feels as hard or harder than a brisk walk for at least ten continuous minutes”), (d) live in the metropolitan area of the study site (upper Midwest), (e) be at least 18 years-old, (f) be able to participate in the study for six weeks and agree to participate in a focus group at the conclusion of the study, (g) possess a smartphone, (h) be able to attend a weekly 60-minute Zoom session one night per week, and (i) be willing to be randomized to the intervention or control condition. Participants were excluded if they did not identify as a woman and Black and/or multiracial Black, were physically active over 90 min per week, live in the metropolitan area of the study site, were unable to participate in the full study, did not possess a smartphone, and were not willing to be randomized to either condition.

Measures

Primary dependent variables

The intervention design was deemed feasible if an average of 15 participants were recruited over three months (from August to October of 2023), with an enrollment goal of 45 participants. Feasibility of the design was also assessed by retention, with a goal of 90%. Due to the group nature of the intervention in the current study, a Stop/Go criteria was not utilized. Level of acceptability was assessed by examining the ratings on a program evaluation form and a program evaluation form that asked participants to respond on a seven-point Likert scale ranging from “very dissatisfied” to “very satisfied.” Focus groups were conducted at the completion of the intervention with PAI participants to gauge in-depth perspectives of the pilot study.

Secondary dependent variables

A shortened 7-Day PAR [23] questionnaire was used to assess self-reported physical activity. The PAR is a well-established and validated measure that has been widely used in behavioral interventions in multiple populations [24, 25]. This 28-item measure has also been shown to have moderate consistency when compared to accelerometer data [26]. Participants were asked whether they engaged in any physical activity in each of the seven assessment days, and if so, how many minutes of moderate, hard, and very hard intensity physical activity they completed. The outcome of minutes-per-week was calculated by adding up the total number of minutes for each day reported, and all intensities were weighted equally.

Self-efficacy for exercise was assessed using a 5-item measure that asked participants to rate their confidence for engaging in physical activity in five different situations [27]. This measure has been validated for adult populations and has an internal consistency of ɑ = 0.76 [28]. The internal consistency for the current sample is ɑ = 0.73.

The 18-item Physical Activity Enjoyment Scale (PACES) assesses enjoyment of physical activity [29]. The PACES has high internal consistency, ɑ = 0.93, and reliability [30]. PACES has also been shown to be reliable and valid in various adult populations [31]. The internal consistency for the current sample is ɑ = 0.67.

Outcome expectations, or the assessment of the consequences of a behavior, was gauged using the nine-item Outcome Expectations for Exercise Scale (OEES) [32]. The OEE has high internal consistency, ɑ = 0.95, and has been shown to have good validity and reliability in samples similar to the current study [32]. The internal consistency for the current sample is ɑ = 0.86.

The Behavioral Regulation in Exercise Scale (BREQ-2) was developed based on Deci and Ryan’s Self-Determination Theory and assesses motivation for physical activity [33]. The BREQ-2 has four subscales, amotivation, extrinsic regulation, introjected regulation, identified regulation, and intrinsic regulation. Internal consistency is above the standard for the field, ɑ = 0.749–0.849 [29]. The BREQ-2 has demonstrated sufficient reliability and validitY [33]. The internal consistency for the current sampleis ɑ = 0.75 for the amotivation subscale, ɑ = 0.72 for the external regulation subscale, ɑ = 0.62 for the introjected motivation subscale, ɑ = 0.65 for the identified regulation subscale, and ɑ = 0.85 for the intrinsic motivation subscale.

The Physical Activity Social Support (PASS) scale is a 13-item measure that assesses family and peer support for physical activity within the past month [34]. The PASS is valid and has high test-retest reliability [34]. Additionally, the PASS has had internal consistency scores ranging from ɑ = 0.61 to ɑ = 0.84 [34]. The internal consistency for the current sample is ɑ = 0.88 for peer social support and ɑ = 0.91 for family social support.

Exploratory aims

The Feelings Scale (FS) was used to measure affect at different points of the group exercise sessions [35]. The FS seeks to understand affective valence (from displeasure to pleasure) during different portions of an exercise session [36]. Participants were asked, “How do you currently feel right now?” immediately before, during (at the halfway point of the session), and immediately after the exercise sessions during. Participants responded on a scale from − 5 (very bad) to 5 (very good). Participants were also asked, “How much are you enjoying this exercise session right now?” before, during, and after the exercise sessions. Participants responded on a Likert-scale of 1 (“not at all”) to 7 (“extremely”). The FS has been shown to be valid for measuring affect in group exercise sessions [36].

Focus groups

Focus groups occurred at two stages of the study: the formative research phase to inform the intervention and at the end of the intervention with the physical activity group. All focus groups were facilitated by a trained moderator who had experience conducting focus groups with Black women. Participants in the formative research phase were asked questions regarding attitudes and experiences toward physical activity as well as intervention specifics, such as motivational topic preferences. This semi-structured focus group was created based on how similar focus groups have been conducted in the literature [14]. Participants in the intervention group engaged in a 60-minute, semi-structured focus group session in which they were asked about various aspects of the intervention, barriers to engaging in the intervention, and facilitators that encouraged participation. The focus group guide is based on previous qualitative research that conducted a similar intervention for Black women [37].

Procedure

Formative focus groups and intervention development

Researchers used theoretical frameworks and similar literature to create a broad structure of potential targeted values, beliefs, and methodological approaches that could be used. Researchers then formed questions based off these frameworks and literature to further understand women’s underlying beliefs about physical activity, strengthening physical activity, and preferences for delivery (see Appendix 1). Then, prior to the recruitment of participants, two focus groups with women who matched the demographics of the intervention were conducted to accomplish the following: (1) Review intervention materials such as exercise session content, motivational construct activities, and counseling session topics, and (2) assess any barriers and facilitators within their environments that should be accounted for in the methodology of the study, in accordance with similar literature in the field [14]. Formative research participants were paid $20 for their time. After the focus groups concluded, the student investigator (SI) and the trained moderator conducted inductive hierarchical content analysis to incorporate results into the intervention structure and design, such as deciding which topics to focus on in the group counseling sessions, the extent to which they would like to connect with one another during the intervention, and preferences for digital application for connection [34].

Behavioral intervention

Participants were recruited via email, fliers, and outreach from community members and leaders at various organizations throughout the community and past participants of similar interventions. Once interest was determined and if eligibility requirements were met, participants were emailed a consent and demographics form. After participants were deemed eligible, they were emailed a consent form, a demographic form, and baseline questionnaires. After completion of the baseline questionnaires, they were informed of which group they were randomly assigned to. Participants were randomized with a 1:1 allocation via the National Institute of Health (NIH) randomization tool to either the intervention or wait-list control condition without any stratification. Participants were not told which group they were assigned to until after they completed the baseline assessments.

Participants randomized to the PAI were invited to participate in a one hour in-person meeting at a community space to review program logistics, meet each other, receive relevant health information, and practice common exercise movements. Participants were emailed five workouts per week that included videos showing proper form for each exercise. These exercises were created with a trained member of the research staff, and consisted of movements such as squats, lunges, push-ups, and abdominal exercises, aimed at targeting all major muscle groups (See Appendix 2). Participants completed three to four sets of six to twelve repetitions, depending on the targeted week intensity Variations of the movements were provided to accommodate all ability levels, and all participants were provided these variations in video and written form each week. Participants were provided with two sets of strength bands with instruction on how to use them if they desired. The video instruction was led by a Black woman, and most Zoom exercise sessions were led by a Black woman, as is recommended by researchers who study culturally-appropriate behavioral health interventions [38]. Workouts slightly increased in difficulty each week regarding the number of repetitions and workout length but had similar movements and structure. Exercise sessions lasted approximately 20–30 min. Participants were also emailed warm-up and cool-down exercises. Participants were asked to complete two workouts in the first half of the intervention per week (weeks one through three), and three in the second half of the intervention per week (weeks four through six).

Participants were sent motivational prompts via WhatsApp on Monday of each week that targeted constructs of Self-Efficacy Theory [39] and Self- Determination Theory [40]. Participants in the intervention group engaged in one 60-minute Zoom session per week to foster connectivity between participants and the research team. In the first half, participants underwent group counseling based on motivational prompts sent via group chat (see Table 2). Then, participants engaged in a 30-minute group exercise session that paralleled workouts sent to them each week. Before the start of the exercise session, participants were told to stop exercising if they experienced shortness of breath, chest pain, and/or pain radiating down one arm, dizziness, muscle weakness, calf pain, or a headache. During the exercise portion of the meeting, all participants completed the Feeling Scale (FS) to assess feelings at different points of the exercise session. In the last week of the intervention, participants were sent the six-week questionnaires and completed focus groups assessing their experiences. At the conclusion of the intervention, intervention group participants participated in a focus group conducted by the SI to assess the acceptability and feasibility of the intervention. They were asked questions about a) their experiences as participants in the study, and suggestions for future interventions (see Appendix 3). Participants in the wait-list control condition were also given access to all behavioral materials, resources, and offered meetings that the intervention group received after 6 weeks.

Table 2.

Overview of zoom group counseling session content and activities

Week	Strategy	Content
1	In-person introductory session	In the introduction session, the PI reviewed the purpose of the Zoom counseling sessions, content covered each week, activities that would be completed, let participants meet the research team and each other, and showed participants key movements with cues.
2	Goal setting and motivation	The SI defined intrinsic motivation and provided examples of intrinsic motivation in life. Then, researchers discussed how important intrinsic joy or motivation was for doing activities and how intrinsic motivation can lead to increased participation. Next, researchers provided strategies for boosting intrinsic motivation, such as journaling. Participants talked about ways that they felt intrinsic motivation in their lives and how they could engage in this thinking during physical activity. This then led into goal setting, in which researchers taught participants about how motivation influences goals, and how to write optimal health goals. Participants created two individualized health goals.
3	Enjoyment	The SI explained how enjoyment of an activity led to sustained engagement in a behavior, and the importance of enjoyment in physical activity, particularly in the face of obstacles and challenges. Participants were then put into a breakout room for an activity in which they were asked to engage in various ways they could find enjoyment in various aspects of physical activity using guided questions from researchers. Participants then came back together to discuss and come up with a list of ways to optimize enjoyment.
4	Social support	The SI discussed the significance of having support from meaningful people in their lives for physical activity. Then, the SI asked participants to identify meaningful people in their lives and develop strategies on how they can engage in physical activity together. Participants then came back to the overall group and discussed thoughts that arose while analyzing support in their lives. Participants worked together to help with questions that come up regarding how to involve others in physical activity.
5	Time management	The SI discussed the benefits of engaging in time management and how time management can assist in starting a new habit and persevering in that activity. Additionally, the SI discussed how time management can help in planning for situations that may lead to setbacks. Then, participants created a weekly schedule that represented a normal week and identified potential areas to fit in physical activity. Then, the group came back together to discuss potential areas of struggle within the group and the group discussed ways in which participants could overcome busy schedules.
6	Overcoming setbacks	In the final session, the SI explained how setbacks are an inevitable part of life and the importance of developing healthy habits. Additionally, researchers discussed common setbacks and strategies to overcome them and continue on with a habit. Researchers stressed the importance of “progress, not perfection.” Then, participants went into smaller groups and discussed setbacks that they experienced in their lives, and others chimed in to provide support or advice. Next, participants came together in the larger group to discuss what was discussed in their group.

Sample size justification

The current study is a feasibility pilot of the culturally-informed strengthening physical activity intervention for Black women, rather than testing efficacy. The sample size of 36 was chosen because intervention participants would be able to share in-depth perspectives of their experiences in the intervention and would provide sufficient information about the feasibility of participating, in accordance with similar trials [41]. This would also allow us to obtain preliminary means for psychosocial outcomes that could be useful for future larger efficacy trials.

Data analysis

Primary outcome analyses

Acceptability was measured by ratings on the program evaluation form for the overall program, the introductory session, at-home workouts, the Zoom sessions, the WhatsApp prompts,. In addition, the program was considered feasible if participants completed, on average, at least 75% of the sessions and 90% were retained at the conclusion of the intervention, defined as completed all post-intervention assessments.

Secondary outcome analyses

Descriptive statistics (e.g. means and standard deviations) were conducted to report means between groups at the baseline and post-intervention by group (PAI and control group). For secondary analysis, a complete case analysis was conducted, and only participants who completed all assessments were included.

Exploratory analyses

Descriptive statistics were obtained for the PAI group on the FS to report means and standard deviations before, during, and after the Zoom workout sessions.

Focus groups

To assess feasibility and acceptability of the pilot intervention as well as discuss areas of strength and growth of the program, focus groups were analyzed using thematic analysis by the SI and a trained moderator. Thematic analysis was used to identify patterns in the data, compare what is in the data, and describe and order the material in a cohesive way [42]. To do so, researchers adhered to the following steps [42]. First, researchers engaged in immersion of the data by reading through the transcripts multiple times. Then, researchers identified and labeled themes from each focus group by tagging relevant concepts. After identifying and labeling, researchers connected and ordered resulting themes through clustering. Once initial connection and clustering took place, researchers cross checked their labels, themes, and clusters to ensure that themes were as accurate as possible. Finally, researchers met and reviewed the data, themes, and clusters, and both researchers engaged in discussion of themes until agreement was reached.

Results

A flowchart of recruitment, screening randomization, and completion is shown in Fig. 1. For the current study, retention was operationalized as completing all assessments at each timepoint. There was no differential drop-out between groups at either time point.

Fig. 1.

Sampling and flow of participants from October 2023 to April 2024

Baseline demographic, psychosocial data, and other outcomes of interest

Participant demographic and baseline data is summarized in Tables 3 and 4. (see Tables 3 and 4)

Table 3.

Zoom session strategies mapped onto motivational constructs

Week	Strategy	Mapping onto Theory
2	Goal setting and motivation	SCT (outcome expectations, goals, self-efficacy) & SDT (competence, autonomy, and relatedness)
3	Enjoyment	SCT (outcome expectations, self-efficacy)
4	Social support	SCT (social environment, self-efficacy) & SDT (relatedness)
5	Time management	SCT (environment, self-regulation) & SDT (competence and relatedness)
6	Overcoming setbacks	SCT (outcome expectations, self-efficacy, environment, self-regulation)

Table 4.

Participant demographics by group

Characteristic	Total Sample (n = 36)	PA Group (n = 18)	Wait-list Group (n = 18)	p-value for group differences
Age (average in years)	44.06(12.63)	41.12(12.60)	46.83(12.37)	.185
Race (%)				.630
African-American or Black	83.8%	83.33%	88.89%
Other	13.9%	16.67%	11.11%
Ethnicity (%)				.074
Hispanic or Latino	8.3%	16.67%	0%
Non-Hispanic or Latino	91.7%	83.33%	100%
Marital Status				.901
Single (never married)	56.70%	71.43%	50%
Married	26.70%	28.57%	28.58%
Divorced	16.70%	14.29%	21.40%
Education				.901
High school graduate	3.2%	6.25%	0%
Some college	29%	31.25%	28.57%
College graduate
Post-graduate	38.7%	31.25%	50%
Income				.945
Under $50,000	16.2%	18.75%	6.67%
Over $50,000	77.40%	68.75%	86.67%
Don't know/refuse	9.7%	12.5%	6.67%
Currently employed (%)	93.10%	85.70%	100%	.168
Children under 18 years old (%)	35.50%	46.67%	25%	.256
Current smokers (% non-smoker)	96.60%	100%	93.33%	.343

Feasibility and acceptability

Acceptability for the intervention program was assessed via the program evaluation survey on a scale of 1 to 7. For the overall program, participants reported an average rating of 6.36 (SD = 0.929) out of 7, which indicated satisfaction with the program. For the Zoom exercise sessions, PAI participants responded positively at 6.14 (SD = 1.10), and participants rated the Zoom counseling sessions with an average of 6.00 (SD = 1.36), both out of 7. Participants rated the individual exercise options at 6.38 out of 7 (SD = 0.961), indicating satisfaction with the workouts and modifications available. For motivational texts, participants reported a mean of 5.57 out of 7 (SD = 1.56), which indicates that on average, participants were “somewhat satisfied” with this aspect of the program.

Participants used the WhatsApp group infrequently, with 33 messages in total replying to the motivational prompts sent each week, and one conversation among participants over the intervention period. The average number of sessions attended was 2.87(SD = 1.85) out of 6, or 47.78% out of 100%. Five participants attended the first in-person session of the intervention. The criteria for meeting intervention design feasibility were recruiting 15 participants in three months of recruitment and retaining 90% of participants at the post-test assessment. Thirty-six participants were recruited from August 2023 to February 2024, which was below our feasibility criteria. Twenty-four of the 36 participants completed all aspects of the study, which was 66.7% retention, which was again below our criteria.

Secondary outcomes

Descriptive statistics of physical activity and related psychosocial outcomes at both baseline and post-intervention timepoint are shown on Table 4. While conclusions regarding differences between groups cannot be made due to sample size limitations, physical activity and self-efficacy for exercise increased from baseline to post-intervention timepoints, while physical activity decreased for the WLC group. Other psychosocial measures of physical activity remained stable or decreased from pre-to-post intervention for both groups.

Exploratory variables

Descriptive statistics of Feeling Scale assessment of enjoyment and affect are before, during, and after the exercise sessions are shown in Table 5.

Table 5.

Self-reported physical activity per week at baseline and post-intervention timepoints by group

Group	Baseline (in minutes) (M(SD))	Post-Intervention (in minutes) (M(SD))
Physical Activity Intervention	63.93(103.93)	164.71(194.63)
Wait-list Control	222.69(450.25)	194.23(240.16)

Focus groups

Ten of the 15 intervention participants who completed the six-week physical activity program participated in the post-intervention focus group. Five participants were unable to participate due to illness, work, or family obligations. The focus groups were led by a trained moderator, a Black woman, using a semi-structured question guide. General reactions to the program. Overall, focus group participants indicated that they enjoyed the program. Some women noted they were intimidated by trying a new workout format and exercising with others on Zoom at the beginning of the program, but they noted that they became more comfortable and empowered by the program as time progressed. Participants enjoyed the strength training aspect of the program, as they were able to learn about correct form for exercises with modifications to support their fitness level. Strengths of the program. When asked what their favorite part of the program was, participants discussed how they enjoyed the Zoom counseling sessions to build community, integrate motivational counseling into exercise, and felt an increased motivation to be active during the study. Participants noted that the sessions were easy to get into, compatible with their pre-existing pain, and appropriately challenging. The videos provided helpful demonstrations and was a tool they could use to review proper form and cues. Weaknesses of the program. When asked about their least favorite aspect of the program, participants unanimously agreed that the WhatsApp feature was the weakest component. They commented that there was a lack of engagement, that the posting felt inauthentic, that they forgot about it or had notifications turned off, and/or they did not have the app and had to download it. Participants agreed that they wanted a way to contact their fellow participants during the duration of the study, but there was not a consensus on one app that would be the best format for this, as there was not a social media or communication app used by all. Suggestions for improvement of the program. When asked for suggestions of how to improve the program for the future, participants were largely reflective of the group meetings. Many recommended adding more Zoom sessions throughout the week to accommodate scheduling conflicts, creating an option for in-person meetings to foster a more authentic connection between participants in the program, and to increase the length of the Zoom sessions from 60 minutes to 90 minutes to have a longer workout period. Additionally, many expressed a need for the structure and delivery of the group meetings to change and a desire for more connection opportunities via group chat.

Overall, the women in the physical activity group expressed that they enjoyed the program overall and felt themselves getting stronger and feeling more confident they could complete the exercise (see Table 6).

Table 6.

Post intervention focus group qualitative findings (n = 10)

Focus group question	Key themes	Representative quote(s)
General reaction to the program	• Empowered • Comfortable with group • Enjoyed exercises • Accountability • Encouragement	“I’ll say for me, I was just a little nervous because I sometimes give up a lot. But I was just happy to have more of a supportive study. I was happy about that.” “Overall, very good. I thought the program was too easy at first. However, it got more challenging over time. Also, [I liked] the group session and the group workouts. I felt challenged and enjoyed it!”
Strengths of the program	• Structure and organization of program • Accompanying materials (videos, cues) • Increased motivation	“I would say [I liked] our Tuesday classes, because it incorporated both having discussions about our exercise habits [and] our intentions. But then we also paired it with exercising with our group, which I really like.” “I liked the videos as well, the instructions for the exercises. But I also really enjoyed the goal setting that we did at the beginning part of each session and talked through what we were going to do when kind of getting our minds set. I really enjoyed that part and kind of setting ourselves up for success. Because I haven’t, well it’s kind of hard to kind of put yourself first, and so I really enjoyed that.”
Weaknesses of the program	• WhatsApp feature • Lack of authentic connection	“I think you also have to think about, “how do you build an online community out of strangers who are just participating in a one-off study?” How do you encourage them to reach out to each other and not make it feel like school [homework requirements]?” “I’m going to be honest, I didn’t really use it. And it has nothing to do with the program, I think it’s just because there are so many chat apps that I have, between work, I’m on a board of directors, I’m in a sorority, so I have a lot of back and forth with chat.
Suggestions for improvement	• More in-person options • More meetings per week • Longer meetings • More holistic health meetings	“If anything, I would say I like being able to be around people. So, instead of doing the whole program completely solo with the exception of the Zoom, I think it would have been nice to be able to actually meet up on a set date and do some of the exercises together.” “I would have actually liked it [the Zoom exercise sessions] to be two hours instead of one, maybe. Or at least 90 minutes. Because I workout, a stretch, a workout, and then another stretch afterwards, like a cool-down period. That would have been good for me.”

Discussion

Acceptability

Overall, participants responded favorably to the program, with an average rating of 6.36 out of 7. Participants rated the individual workout options on average at 6.38, indicating a high level of favorability. This was consistent with the feedback received via the post-intervention focus groups, with almost all participants discussing the various ways in which participation in the program led to increased positive feelings surrounding physical activity and motivation to continue to be active. Many noted that they were intimidated to participate at the start of the program, due to their unfamiliarity with their peers in the group and with the overall structure. They felt this disappeared as they settled into the weekly routine. Many also noted that they enjoyed following along with the research assistant’s demonstration of the movements. They discussed how movement cues helped increase confidence that exercises were being completed correctly. Additionally, participants stated that the workouts were manageable but challenging, and they liked that they were able to choose modifications based on their physical ability. The cues were written alongside the video in a PowerPoint, but some participants mentioned that they would have appreciated the cues being said aloud during the videos. They mentioned that going back and forth between the video and the written instructions was not ideal, so future studies could look at integrating the two forms of instruction. This is in line with other similar physical activity interventions for Black women, which also yielded high acceptability and likelihood that they would recommend this intervention to a friend [6, 16, 41]. Interventions that prioritize the cultural preferences within its methodology and structure may provide increased acceptance, which is related to adherence of the activities in the intervention [6].

Zoom motivational counseling sessions and the Zoom group exercises sessions were rated on average a 6 and 6.14 out of 7, respectively. In focus group responses, participants noted that they enjoyed that the counseling and exercise components were in the same session. This allowed them to incorporate the lessons learned from the counseling component into the physical activity component that followed the counseling component. When asked what motivational topic could be included in future programs, all participants expressed a desire for a session dedicated toward diet and nutrition, and how to pair this with physical activity habits. While this is not a motivational session per se, it does signal a need for a more holistic program that combines both diet and physical activity.

The only component of the intervention that did not reach 75% favorability was the weekly motivational texts sent via WhatsApp. There was very limited engagement in the group chat, both in response to the motivational prompts and between participants. This left out an important element of social support that was intended for participants to experience during the intervention. Participants did not find the weekly motivational text and group chat engaging, and many noted that they would have liked to feel more connected to others in their group throughout the week in between Zoom sessions. A similar intervention noted similar acceptability levels as the current study, with participants noting a lack of engagement and connection with other members in the intervention [41]. Another intervention found that although participants enjoyed the at-home aspect of the intervention to be active for convenience, they were left wanting the in-person connection of group exercise [16]. Although the focus group participants noted that chat was the most preferrable mode of contact, this was not the case in the intervention. In the future, researchers should explore a more extensive onboarding process to determine preferences for engagement.

Participants attended, on average, 2.87 out of the 6 sessions, or 47.78% of the group sessions over the course of the intervention, which speaks to intervention adherence. This is a lower engagement percentage when compared to previous studies. For example, a similar study reported that 19 out of 25 participants completed three of five sessions and another study reported 83% to 87% group attendance [43, 44]. One study including a similar population created makeup sessions that participants could attend, and this led to higher engagement [17]. The study did not require participants attend the first in-person session due to concerns regarding family commitments and time constraints. However, this first in-person session could be useful in creating a stronger initial feeling of support and buy-in to the intervention and should be explored in the future. In the focus groups, participants had various suggestions that could lead to higher engagement and increased adherence in the group session. Some indicated that adding more options for the Zoom sessions that participants could choose to attend would be best for them, while others indicated that in-person sessions would create higher attendance. Future research that uses a similar structure should provide multiple opportunities per week for group participation to achieve higher engagement.

Feasibility

This project aimed to recruit 15 participants per month over three months to meet its criteria for design feasibility. However, recruitment took seven months to reach 36 participants for randomization. Researchers experienced challenges regarding the timing of the intervention, with the first cohort starting near the holiday season, which could have influenced enrollment and retention. Additionally, researchers were unable to partner with a stakeholder who could assist in recruitment, input into the intervention, and dissemination of the results. Future studies should aim to reach out to potential community partners, gauge interest, and build a relationship over time to create a product that speaks to their communities’ needs. 67% of participants remained in the study and completed the final assessments, which was below the set criterion for the current study (90%). Other physical activity studies with Black women have found similar percentages, ranging from 56% to 90% retention [6, 7, 45]. Almost all attrition occurred between the period of eligibility assessment and the start of the intervention, potentially due to the issues in recruitment that led to long lapses in activity and communication. Researchers should explore strategies that keep participants engaged and active in their communication with the research team to increase their likelihood of staying in the intervention (e.g., rewards, larger buy-in from community partnerships), or in completing the randomization process during the eligibility interview. Also, researchers should follow up with participants that dropped out to understand their reason for discontinuing participation to gain insight into reasons for attrition and strategies to minimize dropout in future research and improve design feasbility.

Secondary outcomes

Physical activity levels for both groups at the post-intervention timepoint are shown in Table 5. It is important to note that PA levels were higher than expected at both timepoints, especially given the eligibility criteria was less than 90 min of physical activity per week at baseline [46]. Given that self-report often overestimates physical activity, more objective measures like accelerometers should be used in future research [46]. Similar PA interventions for Black women have found mixed results on whether the programs increased PA based on objective assessments (pedometers and accelerometers) or self-report, and most of these effects were not sustained at follow-up assessments [4, 47]. While researchers did request that participants report which workouts they completed the previous week, there was not enough data to include in the final results. The current study found improvements in self-efficacy, familial social support, and behavioral regulation for the PAI group, but are unable to draw significance to due low sample size. This increase in baseline means echoes the focus group findings, as many participants noted feeling more confident in their ability to do strength training physical activity, and their feelings of excitement about the program. Some focus group participants noted wanting more opportunities to connect with their group, which may lead to increased psychosocial improvements if explored. Future efficacy trials should include larger sample to explore if a similar intervention affects psychosocial variables by group.

Exploratory outcomes

The group Zoom sessions consisted of 30 min of behavioral counseling followed by 30 min of strengthening physical activity. Means of affect and enjoyment increased from pre- exercise to during and after the exercise session, although significance cannot be determined in the current study. This finding is consistent with other studies that have examined similar types of physical activity, where bodyweight exercises have produced higher levels of affect and enjoyment than before the session started [48]. Improvement in affect and enjoyment during physical activity may produce benefits, such as adherence to a PA routine, and may predict PA behavior [49]. Affect was assessed was assessed after a 30-minute behavioral counseling session, which may have affected results. However, future studies should assess affect after physical activity but before behavioral counseling to isolate the effect of physical activity only. This study extends the current research on moderate-intensity resistance training, affect, and enjoyment.

Strengths

The present study had several strengths. First, this was one of the first intervention studies to utilize strength training in a PA program specifically designed for Black women. This study aimed to create a program that was shaped by research within the field and from members of the community through formative focus groups. Given the constraints of in-person interventions that can be difficult to attend due to work, childcare, and transportation obstacles, the current study utilized a virtual format to overcome these challenges. Additionally, given the increasing utilization of technology for our physical health, this study was done almost entirely virtually through email, Zoom, and a group chat.

Limitations

The current study had several limitations that should be noted. First, the study had a small sample size, which limited the ability to derive significance from group differences in assessment. Also, the intervention was short in duration (six weeks) and lacked a follow-up assessment. Second, the questionnaire version of the 7-Day PAR assessed moderate to vigorous physical activity and did not assess strength training. A measure that specifically assessed strength training would have provided more meaningful results for this secondary aim. Additionally, the intervention was originally intended to be a community-based study in partnership with local organizations. The intention was for community partners to aid in recruitment, provide event space, and help create an intervention that could be easily disseminated to other community partners. However, the researchers had challenges in obtaining and maintaining partnerships with larger organizations. Engagement in the program may have been impacted by the lack of a strong relationship with the recruitment sources [13, 50]. Another limitation is the overreporting of physical activity, which was likely due to self-report bias and a lack of clarity on how physical activity was defined. Future studies should explore using accelerometers for both assessment and as a screening purposes. Finally, while most participants did respond to emails and texts from the research team, some were unable or unwilling to complete the surveys sent to them via email, leading to attrition. Future research should provide participants with an electronic and physical option to complete.

Future directions

Few PA interventions for Black women have utilized home-based methods to increase PA and psychosocial constructs by empowering women to complete their choice of exercise plan on their own time and connect virtually. Future research on group-based PA interventions for Black women should focus on community partners who can work with researchers to create an intervention that is informed by their experience and can be disseminated to their members. Researchers should also explore alternative strategies for facilitating authentic connections between participants, whether that be in-person and/or through social media. Finally, future research should consider prioritizing appropriate measures for their outcomes of interest, particularly regarding physical activity assessments. Strength training is a different form of physical activity that may require different types of assessments, such as benchmark strength items or bone density scans, rather than traditional accelerometer approaches. Although the baseline variables including age, household income, education and other demographic characteristics were not significantly different in this pilot study at baseline, differences could be seen in larger trials and should be controlled for in the analyses.

Implications and conclusions

Results indicated that an at-home physical activity program for Black women focusing on strength training is acceptable and enjoyable. However, attendance was lower than previous studies, which indicates a lack of engagement. Other similar studies were able to integrate their study into community programs and spaces, which could have contributed to the lack of attendance and engagement for this study. Future studies should partner with community organizations to find participants with shared values and experiences, as this could create more authentic connections that would lead to a higher engagement rate. Other studies that have done this have seen increases in constructs such as self-regulation and social support [7, 47]. This may then lead to greater increases in relevant psychosocial variables.

Abbreviations

PAI

Physical activity intervention

WLC

Wait–list control

UMN

University of Minnesota

SI

Student investigator

RA

Research assistant

Authors’ contributions

KS was the main author of the manuscript, lead of the intervention, and analyzed all data. BL wasa major editor and author the paper, and advised on specifics of the methodology. DBA, DA, and JSL helped create the manuscript and advised on portions of the intervention. VH assisted in focus group moderation and data analysis. TS and KF assisted in recruitment and delivery of the intervention. All authors read and approved the final manuscript.

Funding

This study has been funded by the University of Minnesota Provost award.

Data availability

The datasets used and/or analyzed during the current study are not publicly available due to participant privacy, but are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

Ethical approval for this study was obtained from The University of Minnesota’s Institutional Review Board (IRB) # STUDY000199542 on July 25th, 2023. Written informed consent was obtained for anonymized participant information to be published in this article.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.