Abstract
Key Points
Fall risk reduction: Online ballet-modern dance classes combined with BFR offer an accessible and safe way to increase exercise intensity for older women, potentially reducing fall risk.
Strength and balance improvements: Participants using BFR showed significant gains in lower-body strength and specific balance measures, while the control group demonstrated more limited improvements.
Feasibility and impact: Adding BFR to online dance classes enhances physiological stress without compromising safety, making it a promising strategy to support independence and quality of life during aging.
Introduction
Age-related increases in falls are attributable to declines in postural stability, which is dependent on sensory information from the visual, vestibulocochlear and proprioceptive systems, as well as strength, muscle mass and mobility.1,2 Falls are a leading cause of injury, hospitalization and death among older adults 3 with women comprising 70.5% of subsequent emergency visits. 4 This higher rate of injury reflects their lower levels of physical activity, strength and bone mass density.4,5 Beginning at age 40, women display significant declines in leg extension power (−1.5% per year). 6 This loss accelerates in women above the age of 75 (−1.8% per year) due to decreases in lean muscular mass, 6 primarily Type II fibers, 7 and increases in intramuscular fat infiltration.6,8 Women are overly impacted by this atrophy as they have lower baseline levels of lean muscle mass.6,9 Atrophy may affect the ability to execute quick postural adjustments and avoid falls. 1 Despite the known benefits of regular physical activity for preserving strength, muscle mass and bone strength, less than 4% of women above the age of 65 are physically active. 10 With the worldwide number of older women projected to grow over the next 10 years from 475.82 million to 642.87 million, 11 the World Health Organization 3 has outlined the need for fall prevention and active aging programs.
Dance is gaining popularity as a social and engaging way for older women to boost their levels of physical fitness. Classes have been shown to improve postural stability after as little as 2 hours per week for 10-weeks.12-15,16 Directional changes, single leg standing time, body rotations, improvisation and precision of movement have all been linked to improved lower limb strength,12,17 reaction time,14,15 balance confidence 17 and postural stability.12-15,18
While dance classes are effective for improving postural stability, many women face barriers to in-person participation due to living in remote locations, lacking transport, being a caregiver at home, or being immunocompromised. Online dance classes offer promise as a way to improve dynamic balance, however their effects on strength are inconsistent potentially due to the intensity limitations imposed by the online environment.16,18 A meta-analysis by Clifford et al 19 found that dance classes did not significantly improve the strength of older adults when compared to other interventions. Blood flow restriction (BFR) is proposed as a novel method to safely mimic a higher exercise intensity and maximize the potential benefits of online dance classes.
BFR uses either pneumatic or elasticized cuffs on the proximal portion of limbs to partially occlude blood vessels going to muscles exercising at low intensity. With the compressive pressure of the bands, commonly ranging between 110 to 200 mmHg, blood flow to exercising muscles is limited. 20 This reduction in blood flow and subsequent hypoxia simulates a high intensity environment and induces physiological stress to promote performance on strength tests to those achieved through traditional high-intensity exercise in older adults.20,21 Using pneumatic cuffs with a mean occlusion pressure of 110 mmHg, Takarada et al 22 demonstrated that 16 weeks of low-intensity resistance training (30%-50% 1RM) with BFR lead to greater increases in isokinetic torque as well as cross-sectional area of the biceps brachialis and brachialis muscles, than low-intensity training without occlusion. Notably, no significant difference was found between the low-intensity group using BFR, and those training at high-intensity without BFR. 22
Elasticized cuffs represent a more feasible alternative to pneumatic cuffs, which are significantly cheaper and may be more accessible for adoption by community centers or dance studios. Since the exact pressure or percentage of arterial occlusion cannot be measured using elasticized cuffs, Wilson et al 23 suggest 7/10 on a perceived tightness scale is commonly used. Using this 7/10, they found greater muscle activation and thickness than training alone, which is conducive to strength adaptations. 23
These strength improvements are related to earlier Type II muscle fiber activation, which promotes strength and recruitment. 22 This may be particularly beneficial for reducing fall risk as postural corrections must be made quickly. Additionally, BFR shows particular promise for older adults who may have comorbidities that contraindicate high-intensity exercise. 24 The safety of BFR for older adults has been confirmed in both clinic and at-home use with extremely low rates of adverse events. 25
To our knowledge, few have examined the use of BFR for improving balance and no studies have combined BFR with dance classes or online exercise classes. This randomized controlled trial investigates whether 12-weeks of online ballet-modern dance classes combined with BFR can produce improvements in the strength and dynamic balance of women aged 65 years and above.
Methods
Participants and Study Design
Women above the age of 65 were recruited for a 12-week randomized controlled trial with pre-, mid- and post-testing. Recruitment ads were distributed through local community centers and a mailing list of past participants. A total of 30 individuals contacted the research team, but one did not meet eligibility criteria as listed in Table 1. 29 enrolled in the study and 18 completed it, as shown in the CONSORT diagram (Figure 1). A priori power analysis was not conducted due to logistical constraints, as well as the exploratory nature of this first BFR study for dance. Participant characteristics for the 18 participants who completed the study can be found in Table 2.
Inclusion and Exclusion Criteria for Participants.
CONSORT diagram of participant enrollment and study completion.
Median (Interquartile Range) of Participant Characteristics, PASE Scores and Attendance.
Abbreviations: BFR, blood flow restriction; BMI, body mass index; IQR, interquartile range; Med, median; P, P-value; PASE, Physical Activity Scale for the Elderly; r, effect size; U, Mann-Whitney U; Z, Z-score.
Stratified randomization into BFR and control groups occurred by matching those with similar physical activity levels and then drawing participant numbers. Baseline physical activity levels were obtained using the Physical Activity Scale for the Elderly (PASE) which was included in the study enrollment questionnaire.
Prior to allocation and pre-testing, Certification of Ethical Acceptability for Research Involving Human Subjects (#30016017) was received from the Human Research Ethics Committee of Concordia University and informed consent was obtained. This trial was registered with ClinicalTrials.gov NCT07011784.
Dance Intervention
Two 75-minute dance classes were held over Zoom every week, for 12 weeks. Exercises were designed by an exercise science graduate student who also worked as a dance instructor for more than 7 years, teaching ballet and modern dance to adult recreational dancers. Two sections of the 12-week program existed, each with their own instructor. The instructors used the same exercises in-class and met weekly to discuss, practice and match their teaching styles.
Each session started with a 15-minute warm-up, followed by pliés, tendus, Graham and Limón modern-dance exercises, and a 5-minute seated stretch recovery (see YouTube Link for archived exercises). Movements emphasized transfer of weight, dynamic balance while standing on one leg, bringing the body off center, fall recovery and strengthening of the lower limbs and core. A helper was present for each Zoom class to track attendance and ensure participants’ safety and participants. All participants were required to keep their webcams on. Recordings of the class were provided to anyone who was absent and completion of the recordings was added to the attendance form.
Blood Flow Restriction Parameters
At the end of the pre-test, participants in the BFR group were given 2-inch-wide elasticized BFR cuffs (manufactured by AEON athletics) and the researcher provided instruction on how to place them on the proximal portion of their thighs. In keeping with Wilson et al, 23 participants were asked to pull the BFR cuffs tight to a perceived tightness of 7/10, characterized by feeling mild discomfort but no pain. Using perceived tightness of 7/10, Gaspar et al 26 found a 41.5% reduction in blood flow volume measured by doppler ultrasound; this diminution of blood flow showed no statistical difference to pneumatic cuffs (set to ~55.3% of arterial occlusion pressure). A mark was put on the cuffs to make it easier to standardize tightness at home. At mid-testing participants were asked to bring the cuffs so that proper placement and use could be checked and the level of tightness could be adjusted. The cuffs were put on before class began and taken off before stretching.
Data Collection
At each lab visit, participants began with the modified Star Excursion Balance Test (mSEBT) followed by strength assessments of 30-Second Sit-to-Stand (30STS) and Calf Raise Senior (CRS).
Dynamic balance
The Star Excursion Balance Test (SEBT) has been used to assess dynamic balance and ankle stability, given its excellent test-retest reliability in older adults (ICC = 0.91-0.95) 27 and its demonstrated ability to predict dynamic balance deficits. 28 Participants stood with their hands on their hips and balanced on their non-dominant leg at the center of an eight-line star, with each line spaced 45° apart and marked on the floor with tape. They were asked to hover their dominant leg above the line as far as possible before lightly tapping the foot on the line and then returning to the center. To ensure safety, as well as reduce fatigue and apprehension, a modification was made to allow a tap of their foot upon returning to the center. After touching the center, participants were instructed to continue to reach the next line. Participants began with the anterior line and moved clockwise to finish with the anterior-medial line. As this modification was made, the cited validity and reliability metrics may not directly represent this test procedure. The results of our modified SEBT will be labeled with acronym “mSEBT”.
Two practice trials were granted and the third was recorded by placing marks on the lines where the participant tapped. The distances from the center to the marks were measured to the nearest 0.50 cm and then normalized by dividing by the participant’s limb length, measured from anterior superior iliac spine to the medial malleolus. If the participant lost balance or shifted their supporting foot, that distance was not recorded and they were allowed to restart at the next line. A helper was present to ensure safety.
30-Second Sit-to-Stand
The 30STS was used to measure lower limb strength as it shows strong correlations to maximal weight adjusted leg press (r = 0.71, 95%CI = 0.53-0.84) and strong test-retest reliability among older adults (ICC = 0.92, 95%CI = 0.87-0.95). 29 The procedure described by Jones et al 29 was followed and the number of repetitions in 30 seconds was recorded.
Calf Raise Senior
The CRS, which has good correlations to isokinetic dynamometry (r = 0.86, P < .001), was used to evaluate plantar flexor strength. Participants were asked to complete the tests according to instructions outlined by André et al 30 and the number of repetitions within 30 seconds was recorded. The mean difference of 3.5 repetitions was used to determine clinical significance. 31
Statistical Analysis
Descriptive statistics were calculated, and normality assumptions were not met when assessed using the Shapiro-Wilk test; therefore, non-parametric tests were employed for statistical analysis. Baseline differences between BFR and Control groups were evaluated using Mann-Whitney U test for demographic variables and pre-test values of all assessments. Time effects among each group were assessed using the Friedman’s test with Wilcoxon Signed-Rank test post hoc. As a mixed ANOVA could not be performed to gain interaction effects, a Mann-Whitney U test was conducted on pre-post percent-change scores (change = ((post-pre)/pre) × 100). All statistical analyses were performed on SPSS-30® (IBM) with an alpha value of 0.05 (P ≤ 0.05).
Results
Baseline Differences and Participation Rate
Table 2 summarizes participant characteristics showing no statistically significant differences between groups at pre-testing. Participants in both BFR and control groups displayed substantial participation with medians of 91.7% (IQR = 33.33; MeanBFR = 79.2% ± 19.77) and 91.7% (IQR = 20.83; MeanControl = 80.6% ± 20.19) respectively.
Dynamic Balance
As shown in Table 3 and Figure 2, statistically significant changes in normalized reach distance were observed in the Control group primarily during the early phase (pre-mid). Significant improvements were detected in the anterior (P = 0.038), anterior-lateral (P = 0.038), lateral (P = 0.008), and posterior-lateral (P = 0.012) directions. These improvements remained statistically significant at post-testing for the anterior-lateral (P = 0.015), lateral (P = 0.011), and posterior-lateral (P = 0.008) directions, but not for the anterior direction (P = 0.093).
Distances Reached as a Ratio of Limb Length During the Modified SEBT Pre, Mid and Post 12-Weeks of Online Dance Classes.
Abbreviations: BFR, blood flow restriction; IQR, interquartile range; Med, median; n/a, not applicable; P, P-value; Z, Z-score; χ2, Chi squared.
The bold entries were included to highlight the significant values.
Normalized distances reached on the mSEBT following 12-weeks of online dance classes with and without BFR.
In the BFR group, statistically significant changes in normalized reach distance were observed later in the intervention. Improvements were identified in the anterior (mid-post: P = 0.038; pre-post: P = 0.012) and lateral (mid-post: P = 0.025; pre-post: P = 0.021) directions. Additional significant changes were observed in the medial half of the mSEBT, including the posterior-medial (pre-mid: P = 0.015; pre-post: P = 0.008; mid-post: P = 0.051), medial (mid-post: P = 0.021), and anterior-medial (pre-post: P = 0.021) directions (Table 3 and Figure 2).
Between-group comparisons of pre-post percent change in normalized reach distance revealed no statistically significant differences in any direction (U = 22.0-38.0, P = 0.145-0.847, Z = 0.22-1.46, r = 0.05-0.34).
Strength
A significantly greater number of repetitions in the 30STS was observed in the BFR group from pre- to mid-intervention (P = 0.012), and this improvement was maintained from pre- to post-intervention (P = 0.020) (Table 4). No significant within-group changes were detected in the control group, and no between-group differences were observed when comparing percent-change scores (U = 39.0, P = 0.894, Z = 0.13, r = 0.03).
Number of Repetitions on Strength Assessments Pre, Mid and Post 12-Weeks of Online Dance Classes With and Without BFR.
Abbreviations: 30STS, 30 Second Sit-to-Stand; BFR, blood flow restriction; CRS, Calf Raise Senior; IQR, interquartile range; Med, median; n/a, not applicable; P, P-value; Z, Z-score; χ2, Chi squared.
The bold entries were included to highlight the significant values.
For the CRS, both groups demonstrated significant increases in repetitions from pre- to post-intervention (BFR: P = 0.005; Control: P = 0.008) and from mid- to post-intervention (BFR: P = 0.018; Control: P = 0.012) (Table 4). These improvements were clinically meaningful in the control group for both mid- to post- (Mdiff = 5.7) and pre- to post-intervention (Mdiff = 9.0), whereas in the BFR group, only the pre- to post-intervention change reached clinical significance (Mdiff = 5.9). No significant between-group differences were identified in percent-change scores (U = 32.0, P = 0.453, Z = 0.75, r = 0.18).
Discussion
Attendance and Safety
This study confirmed the safety and feasibility of using BFR during dance classes and online exercise trials. The BFR group showed similar participation rates to the control group throughout the intervention. This resemblance suggests that BFR was an acceptable addition to the dance classes. The engagement in our classes (including recordings) is consistent with other dance for postural stability research included in a meta-analysis by Clifford et al 19 which showed high attendance rates of above 80%. Our findings in the BFR group were also consistent with Harper et al 32 randomized control trials of BFR walking for older adults which demonstrated 81.4% attendance.
One adverse event of discomfort and “throbbing” in the veins was noted by a participant in the BFR group. It was revealed that she had varicose veins, a contraindication that was not disclosed on her eligibility forms or in the first assessment, though expressly asked. She was asked to stop using the BFR cuffs but completed the final 6 weeks of dance classes. She was not included in the data analysis. No other side effects from the BFR cuffs were reported, highlighting the safety of BFR when used among appropriate participants.
Dynamic Balance
Participants in the Control group reached greater distances from pre-post in the lateral half of the mSEBT. This result is consistent with other online ballet-modern based studies which suggested improvements may result from practice effects. 18 A tendu, which is a fundamental movement in ballet, involves extending the foot out along the floor while keeping the bodyweight supported on a standing leg. Tendus are performed in anterior, lateral and posterior directions, consistent with the progress in the Control group. The BFR group also exhibited significant improvements in anterior and lateral directions but at a later phase (mid-post and pre-post).
Unlike the Control group, the BFR group extended further in the medial half of the mSEBT. Hertel et al 33 demonstrated that short reaches in posterior-medial, medial and anterior-medial directions are important indicators for chronic ankle instability. These gains in posterior-medial and medial distances seem to indicate that the combination of online dance classes with BFR strengthened the muscles involved in ankle control and allowed participants in the BFR group to reach further. Findings by Earl and Hertel 34 indicate that posterior-medial reaches and medial reaches require the greatest tibialis anterior activation. Furthermore, these directions, along with anterior-medial, require the highest degrees of knee and ankle flexion. 34 During the dance classes, the plié exercise (the movement of bending and extending the knees) utilized knee flexors and tibialis anterior and could have contributed to strength increases needed for farther reaching. 35
Progress in posterior-medial and medial reaches may have clinical and practical implications as they are indicators for improved ankle stability. 33 With greater stability, particularly related to dorsiflexors, older women benefit from support during the swing phase of stepping and shifting the center of gravity about the ankle joint when unbalanced. 36
The results suggest that BFR may be important in driving the strength adaptations necessary for mSEBT performance. With mSEBT improvements only occurring after 6 weeks, it mirrors the increases in repetitions on the 30STS. With greater strength, participants may feel more confident to bend their supporting knee and extend their reaching leg further while maintaining their balance.
Lower Limb Strength
The hypothesis that greater strength facilitates mSEBT performance is supported by results for lower limb strength. While both BFR and Control participants showed statistically and clinically significant gains in plantarflexor strength, only the BFR group increased their number of repetitions on the 30STS, demonstrating the added efficacy of online dance classes with BFR for building strength. These findings are consistent with Clarkson et al, 37 who reported that older adults who engaged in twice-weekly BFR walking significantly increased their 30STS repetitions after 6 weeks and demonstrated greater improvements than a walking-only control group. The increase in strength may be explained by Abe’s team who found greater muscle strength and thigh muscle volume after only 3-weeks of BFR-walking, and improved performance on isokinetic knee extensor tests after 6 weeks.21,38,39 BFR may be specifically beneficial to short tests such as the 30STS as during BFR, distal muscles – in this case the knee extensors – experience a hypoxic environment which simulates utilization of glycolytic pathways and promotes fast-twitch Type II fibers.22,40
The observed increase in knee extensor strength is much quicker than in previous studies of dance for older adults which required a minimum of three classes per week for 10-weeks. 17 Furthermore, dance interventions have found inconsistent results for strength gains when compared to other interventions. In a meta-analysis by Clifford et al, 19 dance did not augment strength when compared to no intervention. Our findings indicate that the addition of BFR is an easy and effective way to safely simulate an increase in intensity during online dance classes and to build strength. Further, these improvements in knee extensor strength may aid in making larger hip adjustments when unbalanced. 1
Limitations
A primary limitation of the study is the inability to measure and standardize occlusion pressure using the BFR cuffs. Elastic cuffs do not include a way to measure the restriction of blood flow, and thus a commonly used perceived tightness of 7/10 was selected. While the exact reduction in flow for each participant is unknown, 7/10 of tightness shows comparable occlusive ability to approximately 55.3% arterial occlusion pressure with a sphygmomanometer cuff. 26 The at-home use of BFR also limited the researchers’ ability to ensure 7/10 tightness was maintained throughout the entire session. While participants were reminded at the start of each class to tighten their bands to a 7/10, it is still possible that there was still variability between participants, and consequentially variation in the BFR intervention dose.
A second limitation is the use of a modification for the SEBT. As the test was originally designed for athletes, the modification of tapping the foot to the center was made to cater to our older participants and reduce apprehension and fatigue. While Stockert and Barakatt 27 have validated the use of the SEBT for older adult populations, our modification has not been investigated and therefore limits our ability to directly compare our results to other studies.
Due to the non-normality of the data, it was not possible to obtain group*time interaction effects from a mixed ANOVA. The lack of interaction effects limits the ability to draw conclusions about the magnitude or pattern of change when comparing the BFR and control group. While the results of this study appear to support the addition of BFR to online dance classes, they should be interpreted with caution as no significant differences were found between groups when comparing percent-change scores.
A final limitation is the inability to collect long-term fall tracking on those who completed the intervention. Also, due to difficulties during data collection, it was not possible to record postural stability which would have provided additional insight into the fall risk of the participants.
Strengths and Practical Applications
To date, there are few studies investigating the potential of BFR for improving balance and reducing the risk of falls among older adults. The low rate of adverse events, along with high class participation rate underscore the safety, feasibility and efficacy of using BFR during online dance classes to maximize gains in knee extensor strength and dynamic balance. The low cost of elastic BFR bands makes them a simple addition to ongoing dance for health programs, without compromising the enjoyment of classes. These promising results provide an avenue for further research which aim to extend independence as women age.
Additionally, the remote nature of this intervention allows participants in isolated communities or with caregiver roles at home the opportunity to exercise and express themselves creatively. This accessibility promotes increase in physical activity levels, particularly among underserved individuals, which ultimately serve to reduce risk of falls and increase quality of life.
Conclusion
The addition of BFR to online dance classes provides a safe and positive method to overcome limitations on intensity and stimulate adaptations in muscle strength and dynamic balance. The accessibility and cost-efficiency of this program may allow for older women, regardless of location, to improve their fitness, reduce their risk of falls, and increase their independence and quality of life.
Footnotes
Acknowledgements
We would like to thank our participants as this project would not be possible without their interest and support. We additionally thank Angelika Gnanpragasam, Mike Lagendyk and Mohamed Sangaré for all their help.
Ethical Considerations
Prior to allocation and pre-testing, Certification of Ethical Acceptability for Research Involving Human Subjects (30016017) was received from the Human Research Ethics Committee of Concordia University.
Consent to Participate
Informed consent was obtained from all participants before the intervention and testing. This trial was registered with ClinicalTrials.gov NCT07011784.
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: EHC was supported by the Canadian Graduate Scholarship – Master’s Program Canadian Institutes of Health Research/Instituts de recherche en santé du Canada; Fonds de Recherche Santé Québec – Formation de Maîtrise.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Data Availability Statement
Data is available upon reasonable request.