Effectiveness of a group functional power training program for frail older adults implemented through neighbourhood senior centres – a randomised controlled study


 Background

Several trials have demonstrated the efficacy of resistance training to reduce frailty and improve function of older adults. To narrow the research-practice gap, we designed and evaluated the implementation of a community-delivered group-based functional power training (FPT) program for frail older adults within their neighbourhoods.
Methods

Two-arm, multicentre assessor-blind stratified randomised controlled trial at four local senior activity centres. Older adults (n = 61) with low handgrip strength (HGS) were randomised to intervention (IG) or control (CG) group. The IG underwent the FPT program (power and balance exercises using simple equipments) delivered by a community provider. The 12-week program comprised 2 × 60 mins sessions/wk. CG continued usual activities at the centres. Functional performance (SPPB and TUG), HGS, knee extensor strength (KES), and frailty status were assessed at baseline and 3-month. Program implementation was evaluated using RE-AIM framework.
Results

The program was halted due to Coronavirus Disease 2019 related suspension of senior centre activities. Results are reported from four centres (n = 61), which completed the program. IG showed significant improvement of moderate effect sizes in frailty status (0.36 points, 95CI [0.09, 0.64], p = 0.011) and SPPB (0.51 points, 95CI [0.13, 0.89], p = 0.010). IG improvement in TUG (0.57 s, 95CI [-0.07, 1.20], p = 0.080) did not achieve significance and there were no effects for HGS and KES. Only SPPB showed greater improvement in IG than CG (p = 0.047). The community program exhibited good reach, effectiveness, adoption, and implementation.
Conclusions

FPT is superior to regular activities at local senior centres in improving physical function and can be successfully implemented for frail older adults in their neighbourhoods.
Trial registration:

ClinicalTrials.gov, NCT04438876. Registered 19 June 2020 – Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04438876?term=NCT04438876


Introduction
Community-dwelling older adults are prone to developing frailty (1). Frailty has been de ned as "a clinical state in which there is an increased in an individual's vulnerability for developing an increased dependency and/or mortality when exposed to a stressor" (2). It can occur before 60 years of age and the onset escalates in those aged 70 years and older (3). Frailty is more common in persons with lower education and/or socio-economic status (4). Furthermore, physically frail individuals with low socioeconomic status and social support are more prone to suffer functional disability (5).
Frailty is not a contraindication to exercise but a reason to prescribe it. Frailty can be delayed or reversed through interventions where physical training is a key component, especially during the pre-frail stage (6)(7)(8). There is wide consensus for pre-frail or frail older people to be offered a physical activity program with a progressive, resistance training component (9,10).
Resistance training engages low-velocity contractions at 50-80% of maximal strength. Power training is characterised by performing the concentric phase at high velocity (as far as possible) with a slow eccentric phase to achieve the greatest bene t of muscular power and strength. Power training is effective and has emerged as an alternative modality of resistance training to preserve function of older persons to perform activities of daily living that often require quick, forceful motions (11). Randomised controlled trials have demonstrated that high velocity resistance training could improve physical function among pre-frail (12) and frail individuals (13). Given the high local prevalence of pre-frailty (45%) and frailty (5%) in community-dwelling older adults (4), it is imperative for research efforts to move beyond laboratory-based e cacy trials to evaluate effectiveness in real-world settings, with a focus on implementation and real-world partnerships.
Effective interventions in research settings are often not successfully translated to practice due to poor external validity (14). For example, the requirement of specialised equipment and facility in the aforementioned power training exercise interventions (11)(12)(13) can limit the translation of these programs in community settings that often do not have access to such facilities and equipments. To bridge such research-practice gap, e cacy of interventions need to be examined in targeted population settings to better understand the enablers and challenges of the intervention in actual practice (15).
We had previously shown the feasibility and potential of a small group functional power training (FPT) program using bodyweight, resistance bands and chairs for frail older adults at a local senior activity centre (16). However, this nding needs to be replicated in a larger study at multiple sites to ascertain the effectiveness of the intervention for wider translation. Therefore, the purpose of this study was to examine the effectiveness and evaluate the implementation of an FPT exercise program for pre-frail and frail community-dwelling older adults through local senior activity centres (https://www.healthhub.sg/az/medical-and-care-facilities/8/senior_activity_centre). These centres are located at ground level of residential apartments of public housing and are accessible to older adults with poorer socio-economic status and low social support. Fried frailty criteria was adopted (17), with muscle weakness as an inclusion criteria. It was hypothesised that the program implemented in the local residential community would be effective to improve functional performance and reduce frailty for individuals with low muscle strength.

Study design and participants
A two-arm, multicentre assessor-blind strati ed randomised controlled trial among pre-frail and frail community-dwelling older adults was conducted between March 2019 and February 2020 in four senior activity centres located within the residential estates in Singapore (ClincalTrials.gov registration NCT04438876). To be eligible for the study, participants had to (a) be aged 55 years and older, (b) have low muscle strength, (c) ambulate without human assistance and have no other physical limitations to participation and adherence to exercise, and (d) be able to understand basic instructions. Low muscle strength was de ned as handgrip strength (HGS) less than 26kg and 18kg in men and women respectively according to the Asian Working Group for Sarcopenia (AWGS) 2014 consensus (18). Participants were excluded if they (a) were currently enrolled in another study, (b) had any acute musculoskeletal injury or other contraindication to exercise, (c) were unable to participate in the full duration of the study, (d) were unwilling to participate if not assigned to the intervention group, and (e) were deemed not suitable to participate in exercise by a medical doctor. After initial eligibility screening by senior activity centre staff or research coordinator, a doctor examined each subject for medical clearance prior to exercise participation and excluded subjects who did not meet the medical criteria. Participants were then randomly allocated to either the control group (CG) or the intervention group (IG) with a 1:1 allocation ratio based on computerised block randomisation, strati ed by their HGS. Ethical approval was obtained from the National Healthcare Group DSRB (2018/00593). All participants signed informed consent prior to participation in the study.

Intervention group
The IG underwent a 12-week structured FPT program, conducted by an exercise-science quali ed trainer from a community service provider (Empower Ageing Limited; Singapore; http://www.empower.org.sg). Hourly sessions were held twice weekly at local senior activity centres. The exercise intervention comprised progressive power and balance exercises that targeted both upper and lower body muscles. The list of speci c exercises for each respective session is presented in Table 1 and detailed elsewhere (19). Participants performed three sets of each power exercise, with 10-20 repetitions per set, and 12-60 repetitions per set for balance exercises. For the power training, body weight and/or resistance bands were used as resistance and participants were instructed to move as fast as they can during the concentric phase and slowly during the eccentric phase of the exercise movements. To ensure safety, blood pressure of participants was measured before and after each session with an automated sphygmomanometer (Omron HEM-7121, Omron, Kyoto, Japan). Arterial blood oxygen saturation and heart rate were measured at start, mid-point, and end of each exercise session with pulse oximetry (MD300C63, ChoiceMMed, Bristol, Pennsylvania, USA) to monitor exercise intensity levels. Participant with either (a) blood oxygen levels below 95% saturation; (b) high resting heart rate (>=90 beats per minute); (c) abnormal resting blood pressure (systolic blood pressure>=130 mmHg or diastolic blood pressure >=80 mmHg); (d) giddiness or (e) any form of discomfort did not initiate or continue with training session. Participants also rated their perceived exertion after each exercise set and were encouraged to alert the trainer if they felt any discomfort during the training. We monitored and recorded adverse events throughout the intervention program. In addition, participants also received monthly health education talks on nutrition and cognition, conducted by staff from Geriatric Education and Research Institute.

Control group
Participants in the CG could continue with the available exercise program at the respective senior activity centres. Senior activity centres typically had chairs arranged for participants who followed after daily video of stretching, aerobic and balance exercises produced by the Health Promotion Board (20). Participants then had snacks and socialise over group games provided at the centres. The CG was given an exercise manual with the list of exercises in the intervention programme. CG participants were also encouraged to attend the health education talks. Adherence of CG participants to centre activity was not monitored.

Measurements
Objective physical outcome assessments were conducted at baseline and 3-month follow-up by assessors who were blinded to participants' group allocation.

Physical function assessment
Physical function assessments included HGS (21), knee extensor strength (KES) (22), timed up and go (TUG) (23), and the Short Physical Performance Battery (SPPB) (24). HGS was measured using the Jamar Plus+ Digital Hand Dynamometer (Patterson Medical, Evergreen Boulevard, Cedarburg, USA). KES was measured using a spring gauge strapped 10 cm above the ankle joint, and the highest of four readings (two trials per leg) recorded. For TUG, participants stood up from a chair, walked three metres and back, then sat back down. The test was performed twice, and the average time recorded. SPPB comprised three components: balance, gait speed and repeated chair stands. A composite score of 0-12 points was calculated (25), whereby higher scores indicate better functional performance.

Frailty status assessment
The frailty status of participants was assessed using Cardiovascular Health Study (CHS) Frailty Criteria, which characterises frailty based on ve components: weakness, unintentional weight loss, slowness, exhaustion and low physical activity (17). Weakness was identi ed according the AWGS 2014 criteria as HGS less than 26kg and 18kg for men and women respectively (18). Unintentional weight loss was de ned by either BMI less than 18.5kg/m2 or self-reported unintentional weight loss of at least 4.5 kg (10 pounds) in the last six months. Slowness was determined by 6 m walking speed with speci ed cut-offs based on gender and height. Exhaustion was self-reported through a 3-item questionnaire adapted from the SF-12 survey (26). The Longitudinal Aging Study of Amsterdam Physical Activity Questionnaire was administered to assess participants' physical activity levels (27). Low physical activity was de ned as energy expenditure less than 383 kcal/week and 270 kcal/week for men and women respectively. One point was given for presence of each component, and frailty status classi cation was de ned as robust (0), pre-frail (1-2), and frail (3-5) (17).

Other measures
All participants answered a questionnaire on their baseline demographic information, smoking history, medical conditions, and comorbidities. Anthropometric measurements such as height, weight, body mass index (BMI) and weight circumference were taken during the baseline assessment session. The Mini-Mental State Examination was administered to assess cognitive function in participants. It was scored out of 30, with higher scores indicating better cognitive function (28).

Evaluation of program implementation
The implementation of the FPT intervention was evaluated using the RE-AIM framework (29), a model designed to appraise public health interventions. Present study employed four of the ve dimensions speci ed in the framework: reach, effectiveness, adoption, and implementation. First, "reach" was calculated as the percentage of eligible participants who enrolled in the study. Second, "effectiveness" was assessed based on objective outcome assessments stated above, program attrition rate and participant experience. Participant experience was reported post-intervention in the IG only using a 9-item questionnaire administered by the research team. Participants responded by indicating the extent of agreement with the questionnaire items on a 5-point Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). Third, "adoption" was determined as proportion of senior activity centres approached that agreed to implement the intervention. Fourth, "implementation" was assessed based on delity of intervention delivery at both provider and participant levels. At the provider-level, the extent of deviation between the trainer's delivery and the intended exercise program was recorded by a research coordinator who observed every training session and recorded attendance. At the participant-level, implementation was evaluated by program attendance rate and proportion of the exercise program completed by participants. The intervention was deemed to have good adherence if a mean attendance rate of at least 80% was achieved. The dimension of "maintenance" was excluded as the present study was not designed to determine the longer term effects of the intervention. We monitored and recorded adverse events throughout the course of the program.

Sample size calculation
Based on a priori power analysis (G*Power 3.1.9.3) using a power of 0.90 and error probability of 0.05, a sample size of 50 particpants is required for each group to detect an assumed 20% difference in SPPB between IG and CG. In addition, with an assumption of 15% dropout rate, a sample size of 120 participants was initially targeted.

Statistical analysis
Independent samples t-tests and chi-squared tests were employed to examine differences in baseline measures between CG and IG for continuous and categorical variables respectively. Levene's test was conducted to ensure no violation of equal variance assumption. Linear mixed-effect modelling was performed to examine changes in physical function and frailty status between baseline and 3-month follow-up across both groups. Primary independent variables in each model included treatment groups, time, as well as group x time interaction. The models also included random intercepts to account for correlations between repeated measures for each participant. Data analyses were performed based on the intention-to-treat (ITT) principle (30), and the maximum likelihood method was employed to impute missing values. Post-hoc pairwise comparisons were conducted to examine the main effect of time in respective groups. Statistical signi cance level was set at 0.05, and all analyses were performed using Statistical Package for the Social Science (SPSS Version 20.0, Chicago, IL). Threshold values were selected as standardised effect size (ES) of mean differences and deemed as 0.2, 0.6, 1.2 and 2.0 for small, moderate, large and very large, respectively (31). Figure 1 presents the study ow from screening to analyses. A total of 110 participants were screened for eligibility through partnership with four senior activity centres in this study, of which 61 were randomised to the CG (n = 31) and IG (n = 30). In partnership with a fth senior activity centre, another 50 subjects were screened, 33 completed pre-participation medical examination and 31 eligible signed informed consent on 4 Feb 2020. The rst case of Coronavirus Disease 2019 (COVID- 19) in Singapore was con rmed on 23 January 2020. We could not proceed with the study after health authority mandated suspension of all group senior activities with effect from 8 Feb 2020 and decision was made in May 2020 (with suspension still in force) to close the study and perform analyses on the 61 participants from the four centres. Four participants in the CG and seven participants in the IG did not complete the study. Table 2 presents the descriptive characteristics of both CG and IG. No signi cant differences were found in baseline measures between the two groups.

Effectiveness of program intervention
The outcome measures at baseline and 3-month follow-up are presented in Table 3 and  Therefore, 98.9% of eligible individuals agreed to participate in the FPT training program. However, 31 participants could not start the intervention due to the study being disrupted by COVID-19.

Effectiveness
The effectiveness of the intervention on objective physical outcome measures was reported above. Among the 27 participants who started the intervention, four (14.8%) did not complete the exercise program. One withdrew from the study due to personal reason and one dropped out because of medical reason unrelated to the study. There was no other adverse event during the program. Two participants reported that the exercise intervention was too challenging and dropped out on the fourth and fteenth session, with attendance rate of 25% and 57.1% respectively. The participant experience questionnaire was administered to 23 participants who completed the intervention. All participants agreed that the intervention was positive in terms of organisation, engagement and relevance to daily activities (Table 4).
On average, participants also reported that they bene ted from the intervention and felt happier. In addition, all participants indicated that they would participate in such exercise program in the future. Only one participant disagreed that the intervention improved the social interaction among participants. Adoption 100% adoption rate was achieved at the setting level. All seven senior activity centres with schedule availability that were approached agreed to participate in the study. However, the intervention was not conducted at two centres due to insu cient number of participants who met the study's eligibility criteria.

Implementation
At the provider-level, among the total of 96 sessions conducted across four senior activity centres, two (2.1%) sessions had minor adaptations by the trainer. One session reduced the number of repetitions for one set of power component exercise and the other session prescribed different balance exercises of lower di culty. At the participant-level, the mean attendance rate attained was 87.5% among those who completed the program. Most (87%) participants achieved an attendance rate of at least 80%, and 17.4% (n=4) of the participants completed all the program sessions. On average, participants were found to complete 95.7% of the prescribed exercise program in the sessions they attended. Reasons for failing to complete the program include being late, feeling unwell, and leaving the session early. Seven (30.4%) participants achieved 100% participant delity rate.

Discussion
The present study evaluated the effectiveness and implementation of a 12-week FPT program for pre-frail and frail older adults with low grip strength at their neighbourhood senior activity centres. The FPT program signi cantly reduced frailty and improved physical function performance of the participants. Evaluation of the intervention indicated good reach, effectiveness, adoption, and implementation outcomes. In support of our hypothesis, our study showed that an effective frailty reduction FPT program can be successfully implemented at local senior activity centres by local providers.
Performance of daily activities and life-threatening risks (e.g. falls) are more closely related to muscle power than strength in older adults (32). Structured muscle power training involving specialised equipment has been reported to be bene cial in improving physical function and muscle strength among frail individuals (12,13). The results of the present study support such mode of exercise prescription and provided important evidence on translation by showing that a FPT program implemented in real-world settings can reduce frailty and improve training speci c functional performance. Our result strengthens available evidence that exercise interventions using simple equipment could be effective in reducing frailty (16,33). It is an important nding that such an exercise intervention (34) can be implemented in local community settings as an effective option to complement what is currently available.
The signi cant interaction between group and time found for SPPB in present study suggests that the intervention program was better in improving physical function as compared to the usual exercise program offered at community senior activity centres. Indeed, participants in the IG were found to exhibit small-moderate improvement in SPPB scores after the intervention. In contrast, SPPB scores of the CG did not change. The mean increase of 0.51 points in SPPB scores of IG met the recommended cut-off of 0.5 points in representing a small and clinically meaningful change in physical function among older adults (35). Examination of individual components revealed that the improvement in SPPB scores resulted speci cally from improvement in repeated chair stand performance. This training speci c improvement is not surprising. Previous studies reported that high velocity resistance training is effective in increasing repeated chair rise ability among older adults (36,37). In addition, the use of bodyweight as resistance in exercise programs to simulate daily living activities has been recommended to enhance functional capacity (38). Hence, this interaction effect is likely attributed to the emphasis on high velocity muscle contraction and speci city of the program prescribed exercises to daily activities.
While the program intervention improved frailty status and marginally improved TUG, the changes did not differ signi cantly from that in the CG. Given the small effect size, the lack of signi cance could be attributed to a low statistical power achieved. This was due to an unexpected and mandatory suspension of senior centre activities and the study due to COVID-19, resulting in a smaller sample. Nevertheless, the results showed that the intervention programme was at least as equally effective as the current exercise program offered at the senior activity centres. In contrast to functional performance, the FPT program did not elicit signi cant improvements in both HGS and KES. This differs from previous report of increase in muscle strength among frail older adults with muscle power training (13). The con icting results may be attributed to the difference in intervention protocols between the studies. As the FPT program was designed to improve function performance, the exercise intensity may be inadequate to elicit signi cant strength gains. Similar results were reported in other studies of functional exercise interventions (34,39).
Besides demonstrating effectiveness in physical outcomes, the results also showed that the FPT program is a feasible in terms of reach, participation of frail older persons, participation, adoption and implementation by local providers in actual community settings based on the RE-AIM framework (29). The intervention exhibited good reach with 98.4% of eligible individuals opting to join the study. Despite the drop-out rate of 14.8%, participants who completed the intervention showed good adherence with mean attendance rate of 87.5%. Post-intervention questionnaire results also indicated that participants generally had positive experience of the community-delivered training program. In addition, the intervention showed good delity at both provider-and participant-level with minor but necessary deviation from the intended protocol. This showed that the exercise program was suitable for the targeted vulnerable population. Furthermore, the intervention had excellent adoption rate of 100% from the community senior activity centres approached. However, the ndings also highlighted a potential challenge in which some centres have inadequate number of eligible participants to implement the program. Some spouses of participants wanted to enrolled but did not meet the muscle weakness criteria. It is possible that these participants be involved either as volunteers or participants. Collectively, these outcomes could better inform relevant stakeholders in the delivery of such exercise programs in the community. Senior activity centres receive government subsidy for their programs and operations and depending on their socio-economic status, members either pay a small fee or join for free. This study provides evidence that such a program to maintain function in frail participants warrants additional government funding. As centres do not have the appropriate manpower to conduct such a program, this service can be contracted to a local provider for cost sharing between centres. Due to COVID-19 related suspension of group activities at the senior centres, the provider has worked with some centres to offer FPT program via Facebook livestream (40). A strategy to bridge the digital divide of some older people has been to pair them up with others in their family or neighbours who can help with digital access and engagement with the live online training program. While not speci cally measured in our study, the social engagement has been shown to be an important aspect of adherence to group training (8).
This study demonstrated that a community-delivered FPT program can be effective and feasible to reduce frailty and improve function in vulnerable older persons. However, it is important to acknowledge some limitations associated with the study. First, the study population consists of community-dwelling frail older adults and may not generalise to persons who are not frail nor frail persons in the hospitals or nursing homes. Second, due to the Covid-19 disruption of the study, we were unable to compare any postprogram maintenance effects between the two groups. Given that physical function improvements induced by power training were reported to retain longer as compared to strength training (12), the longer term effects of the FPT program warrant further study.
In conclusion, this study showed that community-delivered FPT program was an effective and feasible intervention for frail older adults in their neighbourhoods. The intervention was superior to exercise program offered at local senior activitiy centres in improving functional performance. Improvements in frailty status and TUG were also observed. Positive implementation outcomes suggest that the program is promising for wider community translation.

Availability of data and materials
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Competing interests
The authors declare that they have no competing interests.

Funding
This research was supported as part of a core funding from the Ministry of Health of Singapore to GERI. Community Services (Senja Senior Activity Centre) and ECON Healthcare Group (Bishan Senior Activity Centre) in running the program. We acknowledge the partnership of Empower Ageing Limited for providing the intervention training services. We thank Dr. Tan Jit Seng and Dr. Shauna Sim Hwei Sian for performing the pre-participation medical screening. We are also thankful for the contribution of Yeo Pei-Shi, Ivana Chan, Sylvia Ngu, Aizuriah bin Mohamed Ali, Queenie Tan, Dr. Lilian Chye and Chua Kai-Shyan in development of the study idea or data collection.  Table 3 Outcome   Supplementary Files