Effect of Community-Based Group Exercise Interventions on Standing Balance and Strength in Independent Living Older Adults

Alqahtani BA, Sparto PJ, Whitney SL, et al. Effect of Community-Based Group Exercise Interventions on standing balance and strength in independent living older adults. Journal of Geriatric Physical Therapy. 2019;42(4):E7-E15. doi:10.1519/jpt.0000000000000221

Link to Original Article: https://pubmed.ncbi.nlm.nih.gov/31592997/

Key Points

1. The study aimed to examine the effects of task-oriented and impairment-based group exercise interventions on standing balance and lower extremity muscle strength in older adults.

2. Participants included 107 older adults who were randomly assigned to either the task-oriented exercise group, impairment-based exercise group, or a waitlist control group.

3. The task-oriented exercise group showed a significant reduction in sway acceleration during most balance conditions over the 12-week period, while the impairment-based exercise group had smaller, non-significant reductions in sway.

4. Both exercise interventions showed a significant reduction in sway compared to the waitlist control group in at least one balance condition.

5. Both the task-oriented and impairment-based exercise groups experienced significant increases in hip abduction strength, and the impairment-based group also had an increase in knee extension strength.

6. The waitlist control group experienced a significant reduction in strength in all muscle groups during the 12-week period.

7. Both exercise groups had improvements in standing balance and lower extremity strength compared to the waitlist control group, but there was no significant difference between the two exercise interventions.

8. The task-oriented exercise group showed a trend toward improvement in static standing balance conditions.

9. The results suggest that both exercise interventions can improve standing balance and lower extremity strength in older adults when compared to not receiving any exercise.

Introduction

The prevalence of falls in community-dwelling older adults is high, with a significant number experiencing recurrent falls and subsequent mobility limitations. Maintaining mobility is crucial for active aging, independence, and overall health and quality of life. Lower extremity muscle weakness and balance impairment contribute to falls and mobility limitations in older adults. Exercise interventions have been developed to address these issues, but not all have been successful in improving balance and mobility. The "On the Move" (OTM) exercise program is a new intervention that incorporates task-oriented motor learning exercises to improve walking and promote independence in older adults. Preliminary data has shown improvements in walking and mobility measures with the OTM program, but its effects on balance and lower extremity strength have not been investigated. Therefore, the purpose of this study is to determine the impact of the OTM program on standing balance performance and lower extremity muscle strength in community-dwelling older adults, comparing it with a standard exercise group and a control group.

Method

Study Design

In summary, this study aimed to compare the effects of the OTM exercise program and a standard exercise program on standing balance and lower-extremity strength in community-dwelling older adults. The study recognized the significance of falls and mobility in this population and sought to address these concerns through the different exercise interventions. The specific details of the parent study were documented elsewhere and served as the basis for the design and implementation of this ancillary study.

Setting and Participants

The study randomly assigned facilities to either the "On the Move" (OTM) exercise group or the standard exercise group. Participants in both groups were then randomly assigned to either the wait list control group or the immediate exercise group. The intervention consisted of a 12-week exercise program. Outcome measurements were taken at baseline and after the intervention or waitlist period. A convenience sample of 131 participants was recruited from various senior communities. The principal investigator explained the purpose, procedures, and potential risks and benefits to interested participants and obtained informed consent. The study took place from April 2014 to May 2016.

Inclusion/Exclusion Criteria

The inclusion criteria for the study were individuals aged 65 years or older, residing in independent living facilities, high rise apartments, or senior community centers, and with the ability to walk independently with a gait speed of 0.60 m/s or faster. Exclusion criteria included non-English speaking individuals, impaired cognition, plans to leave the area for an extended period, progressive neuromuscular disorders, unstable acute illnesses or medical conditions, and inappropriate cardiovascular response to the 6 Minute Walk Test.

Interventions

The study consisted of three groups: the On the Move (OTM) exercise group, the standard exercise group, and the control group. The demographics of the participants were collected, along with the Short Physical Performance Battery (SPPB) test to assess lower extremity function.

Both the OTM and standard exercise interventions were conducted twice a week for 12 weeks. The OTM program included warm-up exercises, stepping and walking exercises, strengthening exercises, and cool-down exercises. The standard program consisted of warm-up exercises, cardiovascular exercises, strengthening exercises, and cool-down exercises. The OTM program focused on goal-oriented stepping and walking patterns to improve coordination and proper weight-shifting, while the standard program was based on existing exercise programs.Participants in the control group continued with their normal daily routine during the waiting period, before receiving either the OTM or standard exercise intervention.

Overall, this study aimed to compare the effects of the OTM exercise program, standard exercise program, and no exercise intervention on standing balance performance and lower extremity muscle strength in community-dwelling older adults.

Outcomes

Standing Balance Test

The standing balance test protocol consisted of two tests: the modified Clinical Test of Sensory Interaction in Balance (mCTSIB) and the standing balance component of the instrumented Short Physical Performance Battery (SPPB). Six different conditions were evaluated, starting with easier and progressing to more challenging conditions. The conditions included standing with feet together on a firm surface with eyes open and closed, standing with feet together on a foam surface with eyes open and closed, standing with a semi-tandem stance on a firm surface with eyes open, and standing with a tandem stance on a firm surface with eyes open. Each condition was performed for 30 seconds, and participants were allowed to perform each condition two times.

To measure postural sway, a dual-axis accelerometer was affixed to the participants' backs at the level of the iliac crest. The accelerometer recorded mediolateral and anteroposterior acceleration of the body. A Labview program and Bluetooth were used to acquire the data. The acceleration data were lowpass filtered and then the Normalized Path Length (NPL) for both anteroposterior and mediolateral acceleration was calculated. A higher NPL value indicates more sway. The NPL formula took into account the time duration, number of time samples, and acceleration data.

In summary, the standing balance test protocol examined the utilization of sensory systems for postural stability and measured postural sway using an accelerometer. The protocol included different conditions that ranged from easier to more challenging. The results were calculated using NPL, with a higher value indicating more sway.

Lower Extremity Strength Testing

The Lower Extremity Strength Testing section of the research paper outlined the methods used to measure lower extremity strength in the study. A uni-axial load cell, connected to an amplifier, was employed to measure the force exerted on the load cell. This load cell was connected to straps that fit around the limb on one end and a stable object on the other. The strength measurements included three maximum voluntary isometric contractions (MVIC) for hip abduction, knee extension, and ankle plantarflexion. These measurements were performed in a sitting position. Each trial consisted of the subject gradually increasing force over 5 seconds, with 30 seconds of rest provided between trials. The peak value from the amplifier was recorded, and the average of the three trials was used in the data analysis. This methodology for measuring lower extremity strength allowed for precise and reliable data collection in the study.

Statistical Analysis

The research paper used both SPSS and SAS software to analyze the data. One-way analysis of variance and chi-square tests were used to compare subject demographics, clinical characteristics, and baseline measurements. An independent t-test and chi-square test were used for participants completing the study and those lost to follow-up. The performance between baseline and post-intervention time points for each group was compared using the Wilcoxon signed-rank test. A linear mixed model was used to examine balance and strength performance across the exercise groups, with treatment group, sites, and participants as the effects, and pre-intervention score and other baseline demographic variables as covariates. Subjects who dropped out were excluded from the analysis. The hypotheses stated that the On the Move (OTM) group would have greater improvement in balance performance compared to the standard exercise (STD) and wait-list (WL) control groups. The OTM and STD exercise groups were also expected to have improved strength compared with the WL group. However, because the ancillary study was not strictly controlled and analysis was only performed on participants who completed both visits, the results were not intention-to-treat. A significance level of α=0.05 was used for all analyses.

RESULTS

The study recruited a total of 131 participants, of which 24 dropped out after the initial baseline testing. The analysis included 107 participants who completed both baseline and post-testing. The participants in the three groups were similar in most baseline characteristics, although the OTM-IM group had fewer participants with at least some college education compared to the STD-IM and WL groups, and a higher prevalence of diabetes compared to the WL group. To prevent confounding, education and diabetes variables were included as covariates in the analysis. The participants who completed the assessments were similar to those who dropped out after the baseline testing. Adherence to the exercise programs was defined as attending at least 80% of the total sessions, and approximately 64% of the OTM-IM group and 78% of the STD-IM group attended 20 or more sessions.

Balance Accelerometry

The study examined the effects of the "On the Move" (OTM) exercise program on standing balance performance and lower extremity muscle strength in community-dwelling older adults. The aim was to compare the results with a standard exercise group and a control group. Falls are a prevalent issue among older adults, so maintaining mobility is crucial.

Balance accelerometry outcomes were measured. The OTM-IM group demonstrated a significant decrease in non-purposeful (NPL) sway in both the anterior-posterior (AP) and medial-lateral (ML) directions for most balance conditions, except standing on a level surface with eyes open. The STD-IM group only showed a significant decrease in AP sway when standing on foam with eyes closed. Participants on the waitlist (WL) showed a significant increase in AP sway when standing on a level surface with eyes open but a significant decrease in ML sway when standing on a compliant surface with eyes closed.

After adjusting for baseline values and covariates, the OTM-IM group consistently showed a greater reduction in sway compared to the STD-IM group, although the mean change was not significant. Both the OTM and standard exercise groups exhibited a significant decrease in postural sway compared to the WL control group. Specifically, the OTM-IM group demonstrated a significant decrease in AP sway in three out of six test conditions, as well as during tandem and semi-tandem stances in the ML axis. The STD-IM group also showed a significant reduction in sway in the AP sway when standing on a firm surface with eyes open and when standing on foam with eyes open.

In summary, the OTM exercise program had a positive impact on standing balance performance, showing a greater reduction in sway compared to the standard exercise group and the control group. Both exercise groups demonstrated improvements in postural sway compared to the control group, highlighting the importance of exercise in maintaining balance and mobility for older adults.

Muscle Strength

The study aimed to investigate the effects of the "On the Move" (OTM) exercise program on standing balance performance and lower extremity muscle strength in community-dwelling older adults. The prevalence of falls in older adults and the importance of maintaining mobility were highlighted.

In terms of muscle strength, the results showed that both the OTM-IM and STD-IM (standard exercise) groups experienced an increase in knee extension and hip abduction strength, ranging from 2.9% to 10.5%. However, there was a slight decrease in ankle plantarflexion strength, ranging from -0.6% to -2.4%. The WL control group, on the other hand, showed a clear decrease in muscle strength, ranging from -10.7% to -13.2%.

After adjusting for baseline values and potential covariates, there was no significant mean change between the OTM-IM and STD-IM groups for all three muscle groups. However, both exercise groups demonstrated a significant increase in muscle strength compared to the WL control group. Specifically, the OTM-IM group showed a significant increase in all three muscle groups compared to the control group. The same was observed for the STD-IM group, with significant increases in muscle strength across all three groups.

Overall, the study suggests that both the OTM and standard exercise groups were effective in improving muscle strength when compared to the control group. This finding highlights the importance of exercise in older adults for maintaining muscle strength and mobility, which can ultimately help reduce the risk of falls.

DISCUSSION

The main objective of the study was to evaluate the impact of the "On the Move" (OTM) exercise program on standing balance performance and lower extremity muscle strength in community-dwelling older adults. The study found that both the OTM exercise program and a standard exercise program led to improvements in balance and muscle strength compared to not receiving any exercise. However, the OTM group showed a greater reduction in sway and improvement in postural control in the medial-lateral direction while standing, suggesting that the OTM program was more challenging and beneficial to the postural control system. The study also found that a longer program duration or larger sample size might have further differentiated the two groups, and lower adherence to the OTM program may have underestimated its effectiveness. It was noted that balance is a task-specific outcome, and previous studies have shown that exercise programs designed to improve muscle strength are not as effective as task-oriented balance training. The study results supported the hypothesis that there would be no significant difference in muscle strength improvement between the two exercise groups since they both included similar strengthening components. However, the improvement in muscle strength was greater in both exercise groups compared to the waitlist control group, which experienced a decline in muscle strength. The study concluded that enrollment in either exercise program would result in significant improvements in balance and lower extremity strength compared to not participating in any exercise activities, and a combination of strength training and challenging balance exercises is recommended to prevent falls in older adults. The study acknowledged limitations such as the smaller sample size, non-random selection, and high number of dropouts, which may affect the generalizability of the results.

CONCLUSION

The objective of this study was to determine the effects of the "On the Move" (OTM) exercise program on standing balance performance and lower extremity muscle strength in community-dwelling older adults. The study compared the results of the OTM exercise program with a standard exercise group and a waitlist control group.

The results showed that both exercise interventions, the OTM exercise program and the standard exercise group, led to a significant improvement in both balance accelerometry measures and lower extremity muscle strength compared to the waitlist control group. However, there was no significant difference between the two exercise interventions.

Although there was no significant difference, the OTM exercise program showed a trend toward improvement in static standing balance. However, it did not show any improvement in lower extremity strength.

The study design involved comparing the effects of the OTM exercise program with the standard exercise program. Eighteen facilities out of 32 were used for this ancillary study.

The study also measured the percentage change in lower extremity muscle strength between baseline and post-intervention for the exercise groups. Additionally, the mean change in balance performance was measured using the normalized path length (NPL) of the postural sway acceleration (mG/s) across the 12-week intervention period for all three groups.

In conclusion, the study found that both the OTM exercise program and the standard exercise program were effective in improving standing balance performance and lower extremity muscle strength in community-dwelling older adults compared to a waitlist control group. However, there was no significant difference between the two exercise interventions. The OTM exercise program showed potential for improving static standing balance, although it did not have an impact on lower extremity strength.

Opportunities for Future Research

1. Investigate the long-term effects of task-oriented and impairment-based group exercise interventions on standing balance and lower extremity muscle strength in older adults.

2. Explore the effectiveness of the On the Move (OTM) task-oriented exercise program on dynamic standing balance in older adults.

3. Examine the impact of the Standard Exercise Program on postural sway in different balance conditions in older adults.

4. Investigate the association between adherence to the OTM exercise program and improvements in balance and muscle strength.

5. Evaluate the effects of longer-duration task-oriented exercise interventions on balance and muscle strength in older adults.

6. Assess the impact of high-intensity progressive resistance training on standing balance and lower extremity muscle strength in older adults.

7. Examine the factors that contribute to the effectiveness of exercise interventions in improving balance and muscle strength in older adults.