Enhancing Balance and Strength in Older Adults: The Impact of Pilates and Vibro-Swing Exercises

Abstract

Background

The Vibro-Swing system consists of 2 spiraled tubes containing 4 steel balls that move to generate a vibrational musculoskeletal and nervous system stimulus. This study included 45 older adults and aimed to compare balance, muscle strength, and proprioception with and without a 6-week program of Pilates training using the Vibro-Swing system.

Material/Methods

The present study included 45 older adults (mean age: 78.31±4.50). The experimental group (n=24) underwent a Pilates with Vibro-Swing exercise. The control group (n=21) participated in regular Pilates exercise. Both groups engaged in exercise for 40–50 minutes per session, twice a week, for 6 weeks, resulting in a total of 12 intervention sessions. Assessments were conducted before and after the intervention. The pre-post test evaluated balance (gait analysis, 10-meter walk test [10 MWT], functional reach test [FRT]), muscle strength (Five Times Sit-to-Stand Test [FTSS], grip strength), and proprioception (wrist joint position sense [WRT_30°]).

Results

The experimental group exhibited statistically significant differences in velocity, cadence, 10MWT, FRT, FTSS, right grip, left grip, and wrist joint position sense (extension 30°) between the pre- and post-test (P>0.05). The experimental group exhibited statistically significant differences in gait velocity, cadence, 10 MWT, FTSS, right grip strength, FRT, and [WRT_30°] results compared with the control group (P>0.05).

Conclusions

The Pilates with Vibro-Swing exercise resulted in greater improvements in balance, muscle strength, and wrist joint proprioception.

Introduction

The global population is aging rapidly because of improvements in healthcare and living standards. Currently, people aged 60 years or older constitute 11% of the total world population. The proportion of the elderly population is expected to increase gradually, reaching 22% by 2050 [1,2]. Aging can lead to declines in physical and cognitive functioning of humans and is accompanied by the possibility of developing age-related diseases [3]. In the context of healthy living for older adults, maintaining balance and mobility is crucial for enhancing the quality of life, and impairment of these abilities increases the risk of falling [4]. It is estimated that 13% of individuals aged 65–69 years who self-report balance problems actually have a balance disorder, increasing to 46% for those aged 85 and older [5,6]. If the upper extremities are functional, the sensorimotor system, including proprioception, is intact, and a fall occurs, the likelihood severe injury decreases [7,8]. It is estimated that approximately 28–35% of people over the age of 65 experience falls each year [9]. More than one-third of them had a blow to the head during a fall. Of these, 75% tried unsuccessfully to use their arms to prevent impact [10]. If the postural control system is intact, including appropriate upper-extremity responses, a fall from standing height in an adult is rarely associated with severe injury [11,12].

Strengthening core muscles provides stability to the surrounding muscles, including the core, which can improve an individual’s ability to maintain balance [13,14]. In particular, Pilates is a method of exercise that focuses on stabilizing the center of the body and activating deep trunk muscles [15,16]. A 2015 study by Barker et al found that strengthening core muscles through Pilates exercises can improve balance, which is an important risk factor for falls in older adults [17].

Pilates exercises are not limited to mat exercises; they can also be performed using a variety of tools [18]. Pilates also can be performed using a Smovey ring^® that allows for Vibro-Swing movements. As the beads move across the corrugated hose, they generate vibrations of approximately 0–60 Hz [19]. The Vibro-Swing exercise with the Smovey ring^® requires a significant degree of core muscle engagement to maintain center and balance, as the user holds the tool and swings the distal limb in an arc motion. Another advantage of this approach is that it allows individuals to regulate exercise intensity by adjusting their posture and movements. This enables them to perform exercise correctly without the risk of injury [19,20].

Pilates and Vibro-Swing exercises have been recommended as exercise programs for older and middle-aged adults because they are can be suitably adapted to appropriate exercise intensity through the use of exercise postures, movements, and tools, thus facilitating the achievement of numerous exercise outcomes [19,20]. However, there is a paucity of research investigating the combination of these 2 exercises and their application in older adults. Therefore, this study included 45 older adults and aimed to compare balance, muscle strength, and proprioception with and without a 6-week program of Pilates training using the Vibro-Swing system.

Material and Methods

The study protocol was approved by the Institute Review Board of the University (SYU 2023-07-008-005). Before the study began, participants were informed of the purpose, procedures, and expected effects of the study. All subjects signed a consent form before beginning the study. All methods were performed in accordance with the relevant guidelines and regulations. The study followed CONSORT guidelines for randomized controlled research. The study was registered at the Clinical Research Information Service (CRIS) (KCT0009319).

Participants

The subjects in this study were older people who attended a senior welfare center in Seoul, South Korea. The G*Power 3.1 program was used to calculate the sample size. A two-tailed t test with statistical power (1−β)=0.8, significance level (α)=0.05, and effect size (ɖ)=0.8 indicated that each group required at least 21 subjects. The using the following inclusion criteria: (1) age 65 years or older; (2) no upper-extremity function problems; no neurological or musculoskeletal conditions that would interfere with exercise performance; (3) ability to communicate and understand the exercise process; (4) ability to perform a series of exercises without difficulty; and (5) ability to read and write. Participants were also screened using the following exclusion criteria: (1) shoulder and wrist joint surgery within the last 6 months; (2) limited or painful upper-extremity range of motion; (3) neurological or musculoskeletal conditions that can interfere with exercise performance; (4) difficulty in reading and understanding written language; (4) visual, vestibular, or somatosensory problems, or dizziness. To perform the randomization procedure for each group of subjects, the subjects were divided by random sampling using random numbers generated by a computer program (Microsoft Co., Redmond, WA, USA) (Figure 1). A total of 60 subjects were recruited and randomly assigned to 2 groups, with 30 subjects in each group. However, 15 participants were unable to complete the study due to reasons related to their personal health problems and other factors. The 2 groups were homogeneous with respect to their general characteristics. Age, height, and weight were compared between the 2 groups, but no significant differences were observed (Table 1).

Figure 1.

Flow diagram of the study.

Table 1.

General characteristics of subjects (N=45).

	EG (n=24)	CG (n=21)	t(p)
Gender (Male/Female)	24 (0/24)	21 (1/20)	1.071 (0. 290)
Age (year)	78.46±5.12	78.14±3.9	0.230 (0.819)
Height (cm)	152.12±1.07	154.62±8.77	−1.156 (0.254)
Weight (kg)	60.0±5.11	56.0±8.7	1.586 (0.120)

EG – Experimental group; CG – Control group; Values are expressed as mean±standard deviation.

Intervention

Both groups participated in a 6-week intervention program, which consisted of twice-weekly sessions, with a total of 12 sessions and 40–50 minutes per session. The program was divided into 3 distinct phases: warm-up, main, and cool-down. The exercise included a 10-minute warm-up, 20-minute main exercise, and 10-minute cool-down exercise. Rest periods were incorporated between movement changes. The experimental group engaged in a Pilates exercise utilizing the Smovey ring^®, whereas the control group participated in a mat Pilates exercise. The pre-post test evaluated balance (Gait analysis, 10-meter walk test [10 MWT], functional reach test [FRT]), muscle strength (Five Times Sit-to-Stand Test [FTSS], grip strength), and proprioception (wrist joint position sense [WRT_30°]).

Experimental Group

The exercise program used Pilates movements (eg, Dead bug, Bridge, Bird dog, Spine twist) and added swinging movements using the Smovey ring^® (Figures 2, 3). The Pilates movement was based on a previous study [21,22]. A qualified Pilates instructor conducted an exercise program at the senior welfare center.

Figure 2.

Smovey ring^®.

Figure 3.

The Pilates group exercise utilized the Smovey ring^®.

Control Group

The control group engaged in the same movements and exercise program as the experimental group. The control group also had a Pilates instructor lead an exercise program. The control group engaged in range-of-motion exercises (ROM) or clapping in lieu of the Vibro-Swing movements.

Outcome Measurements

Dynamic Balance

Gait analysis

The gait analysis was conducted using the GAITRite^® (GaitRite, CIR system, Inc, USA, 2008). In this study, the subjects were asked to continue walking on the mat without slowing down. We emphasized walking at a comfortable pace and used the average of the 3 measurements. All subjects wore the same type of closed-toe indoor shoes [23,24]. The test has a reliability of r=.90 [25].

10 Meter Walk Test (10 MWT)

For the 10 MWT, the subjects were instructed to walk at a comfortable pace along a straight line with an extension of 2 m before and 2 m after the 10-m distance to avoid assessing deceleration and acceleration of walking speed. The evaluator measured with a second hand at the point where the subject passed 2 m and the 10-m walk test began. The stopwatch was stopped at 10 meters. Depending on the subject’s condition, an orthosis may be used, and post-assessment should be performed using the same orthosis [26]. For this study, the average of 3 measurements was used. The reliability of 10 MWT is 0.96–0.98 (ICC=0.96–0.98) [27].

Static Balance

Functional Reach Test (FRT)

A ruler was placed horizontally on the wall at shoulder height, and the subject stood on a fixed surface approximately 10 cm from the wall with feet shoulder width apart and the arm raised parallel to the ruler. The position of the end of the metacarpophalangeal joint and the distance travelled by the end of the metacarpophalangeal joint were measured by having the subject extend the arm forward as far as possible while maintaining the base of support. For this study, the average of 3 measurements was used. Test-retest and inter-rater reliability was high, with r=.89 and r=.98, respectively [28].

Muscle Strength

Five Times Sit to Stand Test (FTSS)

At the start of the test, the subjects sat on a chair with a standardized seat height (46 cm) and leaned back until they could bend their knees comfortably. The subjects were asked to sit with their feet on the floor and arms crossed. The time taken to move between sitting and standing positions was recorded 5 times as quickly as possible. The time was measured with a stopwatch. For this study, the average of 3 measurements was used. The test–retest reliability was ICC=0.95 [29,30].

Handgrip Strength

Handgrip strength was measured in a seated position using an adjustable Jamar dynamometer (J00105, Jamar, USA, 2015). The participants were instructed to hold the dynamometer in a position of 90° flexion of the elbow joint, with the forearm in a neutral position. The left and right hands were assessed alternately, with a 1-minute rest between assessments. Two measurements were taken on each of the right and left hands, and the mean value was calculated. The test–retest reliability was ICC=0.97 [31].

Proprioception

Joint position Sense Test

Proprioception of wrist joint position sense was assessed using Goniometers (Goniometer PVC; Anymedi, South Korea, 2008). To measure the wrist joint position sensation, the subject placed the palm of the hand, with the third finger as a reference point on the moving arm and the fixed arm on the distal forearm. The examiner asked the subject to close his/her eyes and passively extend the wrist (extension angle: 30°) and hold it for approximately 3 seconds, reminding the subject to remember the joint angle. The subject was then asked to return to the resting position and move to that angle that he or she remembered. For this study, the average of 3 measurements was used. The test-retest reliability of this test was ICC >0.75 [32,33].

Statistical Analysis

The data were analyzed using SPSS version 22.0 for Windows 10 (IBM, Inc., Armonk, NY, USA). The normality of continuous variables was tested using the Kolmogorov-Smirnov test. The general characteristics of the participants were analyzed using the chi-squared test and independent t test. An independent t test was used to determine differences between the groups, and a paired t test was used to compare pre- and post-intervention differences within each group. All statistical significance levels were set at P<0.05.

Results

Dynamic balance

Gait

In the experimental group, gait velocity increased from 115.30 m/s to 120.19 m/s, cadence increased from 119.57 strides/min to 122.74 strides/min, right foot step time (step time_R) decreased from 0.50 m/s to 0.49 m/s, and left foot step time (step time_L) decreased from 0.51 m/s to 0.50 m/s (P<0.05). A comparison of the 2 groups revealed significant differences in gait velocity and cadence in the experimental group (p<0.05) (Table 2).

Table 2.

Gait and 10 meter walk test between groups (N=45).

	Group	Pre-exercise	Post-exercise	t (p)
Velocity (m/s)	EG	115.30±21.37	120.19±12.18*	2.303 (0.026)*
	CG	119.63±25.70	120.70±19.74
Cadence (steps/min)	EG	119.57±10.16	122.74±10.02*	2.210 (0.032)*
	CG	120.33±14.21	120.22±10.73
Right step time (sec)	EG	0.50±0.42	0.49±0.04*	1.208 (0.233)
	CG	0.51±0.08	0.50±0.05
Left step time (sec)	EG	0.51±0.42	0.50±0.41*	−0.136 (0.893)
	CG	0.51±0.07	0.51±0.51
10 MWT(s)	EG	11.08±2.40	9.72±1.72*	2.077 (0.044)*
	CG	10.94±1.40	10.26±1.54*

Values are mean±SD; EG – Experimental group; CG – Control group;

^*was significant difference within group (^* p<0.05).

10 MWT

In the 10 MWT, the speed of the experimental group increased from 11.08 to 9.72 seconds when comparing before and after the intervention, with a significant difference in the experimental group (P<0.05). The pre-post comparison for the control group changed from 10.94 seconds to 10.26 seconds, and the difference was statistically significant (P<0.05). A comparison of the experimental and control groups revealed a significant difference in the 10MWT in the experimental group (P<0.05) (Table 2).

Static Balance

FRT

The static balance FRT in the experimental group increased from 22.48 cm to 48.95 cm after the experiment, which was statistically significant (P<0.05). When comparing the 2 groups after the intervention, the difference in the experimental group was significantly more than in the control group (P<0.05) (Table 3).

Table 3.

Functional reach test between groups (N=45).

	Group	Pre-exercise	Post-exercise	t (p)
FRT (cm)	EG	22.48±8.80	48.95±11.20*	9.695 (0.00)*
	CG	32.62±8.87	31.84±7.24*

Values are mean±SD; EG – Experimental group; CG – Control group; FRT – functional reach test;

^*was significant difference within group (^* p<0.05).

Muscle Strength

FTSS

The pre-post difference for the FTSS in the experimental group was significant, from 13.23 seconds to 10.17 seconds (P<0.05). The pre-post difference in the control group changed from 7.62 to 6.96 seconds but was not significant. The between-group comparison between the experimental and control groups revealed a significant difference (P<0.05) (Table 4).

Table 4.

Muscle strength test between groups (N=45).

	Group	Pre-exercise	Post-exercise	t (p)
FTSS (sec)	EG	13.23±4.42	10.17±2.07*	2.833 (0.007)*
	CG	7.62±1.69	6.96±1.71
Right grip (kg)	EG	17.80±3.16	20.56±3.43*	2.995 (0.005)*
	CG	23.24±7.99	22.74±6.46
Left grip (kg)	EG	17.60±3.77	20.00±3.36*	1.856 (0.071)
	CG	23.73±7.65	23.90±6.63

Values are mean±SD; EG – Experimental group; CG – Control group; FTSS – five times sit to stand;

^*was significant difference within group (^* p<0.05).

Grip

For grip strength, there was a significant difference between pre-post intervention for the experimental group, from 17.80 kg to 20.56 kg for the right grip and from 17.60 kg to 20.00 kg for the left grip (P<0.05). A comparison of the experimental and control groups revealed a significant difference in the strength of the right grip in the experimental group (P<0.05) (Table 4).

Proprioception

The absolute value of the angle away from the wrist reference angle of 30° was used. The experimental group showed a decreased from 5.56° to 3.56° from pre- to post-intervention. A comparison of the 2 groups revealed significant differences in WRT_30° in the experimental group (P<0.05) (Table 5).

Table 5.

Wrist joint position sense test between groups (N=45).

	Group	Pre-exercise	Post-exercise	t (p)
WRT_30 (°)	EG	5.56±3.17	3.56±2.49*	−2.15 (0.037)*
	CG	7.06±4.62	6.19±5.40

Values are mean±SD; EG – Experimental group; CG – Control group; WRT – wrist joint position sense test;

^*was significant difference within group (^* p<0.05).

Discussion

The aim of this study was to examine the impact of a 6-week Pilates program incorporating Vibro-Swing exercises on balance and physical performance in older adults. Significant improvements were observed in gait speed, cadence, 10MWT, FRT, FTSS, right grip strength, and wrist position sense test (30° extension) in the experimental group compared to the control group.

Balance is the ability of the body to maintain a desired posture in a fixed position or perform functional tasks with purposeful movement without compromising the established base of support; it is the activity of shifting the center of gravity in response to muscle activity [34,35]. Pilates is a widely used exercise that activates the muscles of the core. The method focuses on strengthening the deep core stabilizer muscles through control and conscious movements, which allows practitioners to improve fitness, muscle tone, posture, flexibility, and balance [15,36,37]. Granacher et al [38] studied 32 older adults who performed core muscle strengthening exercises for 9 weeks. A previous study reported that strengthening unstable core muscles improves spinal mobility, which may subsequently affect postural control and functional task performance. In addition, these effects could improve the negative symptoms related to balance and functional mobility that occur with age [38].

The experimental group used a Smovey ring^® to perform the Vibro-Swing exercises in this study. This exercise tool is users to perform a swinging motion with their upper limbs. This exercise strengthens the core muscles by requiring the user to maintain body alignment [39,40]. This enables the subject to undertake more rigorous stability training exercises to maintain balance. This contributed to stronger and more effective exercise performance in the experimental group than in the control group [41]. Consequently, Vibro-Swing exercises with a Smovey ring^® can enhance the efficacy of core muscles, which can mitigate functional issues resulting from core muscle weakness [19,34,42,43].

Increased strength improves neural adaptations such as physical function, activation of the prime mover (the muscle most responsible for a joint action under load), and cooperation of synergists [44]. The results of the FTSS test, which indicates lower-extremity strength, were found to be statistically significant in both the pre- and post-assessment of this study. When comparing the 2 groups, the experimental group showed significant values. The more significant values in the experimental group were due to upper-limb swinging movements. A 2004 study by Huang and Ferris examined neuromuscular recruitment and activation between the upper and lower extremities when subjects were lying down and performing externally-driven and self-driven gait movements [45]. They found muscle activation in the lower limb increased during voluntary upper-limb movement and that the amplitude of electromyography (EMG) increased with increasing resistance and movement of the upper limb. In addition, EMG activation was observed over the same time period during voluntary upper-limb movement. These results suggest that active upper-limb movements increase lower-limb neuromuscular activation during cyclic stepping. Furthermore, rhythmic upper-limb movements during gait increase lower-limb neuromuscular recruitment and lower-limb muscle activity [46]. Prior research has suggested that this could be the result of spinal cord connections within the gait neural network, which control the movements of the body’s upper and lower limbs, or neural cross-talk at the level of spinal cord nerves, resulting in mirror movements or contralateral irradiation, where muscle activity on one side causes unintended muscle activity on the other side [45,47,48].

The results of the present study show that the strength of both the right and left grips was improved in the experimental group when comparing pre-post, and that the right grip strength was significantly improved in the experimental group when comparing the experimental and control groups (P>0.05). Grip strength can be used as a proxy for physical function and as a biomarker for aging. Grip strength is indicative of overall body strength and has been suggested as a predictor of falls, disease-related mortality, bone density, fractures, cognition, depression, and hospitalization [49,50]. These results suggest that the experimental group used the Vibro-Swing exercise tool to perform stronger exercises than the control group, and that gripping and swinging movements of the hand, or the exercise itself, contributed to the improvement in grip strength [51]. Also, vibration is transmitted to the tendons at the same time as involuntary contraction, and the activity of the muscles gradually increases, while the activity of the antagonist muscle decreases, further increasing the effectiveness of the exercise [52].

When comparing the proprioception of the wrist joint between the experimental group and the control group in our study, a significant value was found at 30° of wrist extension in the experimental group. A 2016 study by Cuppone et al (2016) showed similar results; the proprioceptive training group with vibrotactile feedback (VTF) showed a 38% improvement in the proprioceptive accuracy of wrist joint position sensation compared to the group with no proprioceptive training and the group with proprioceptive training alone, resulting in higher gains and significantly less dependence on training devices when performing motor tasks [53]. Similarly, the results of this study suggest that the vibration stimulus provided by shaking the Smovey ring^® can enhance sensory information transfer or provide error feedback related to movement, which may enhance motor learning and reduce the error range.

This study has several limitations. First, a larger sample size is required to generalize our findings. Second, the 6-week duration of the Pilates program was not long enough to determine the value of expected benefits, and there was no measurement of the persistence of the effects afterward. Third, the study did not control for each individual’s daily life habits, which may have influenced the results. Future studies should be more objective and accurate with more subjects and standardized variables.

Conclusions

The findings of this study indicate that Pilates with Vibro-Swing exercise results in the leads to improvements in dynamic balance, static balance, strength, and wrist joint proprioception. Pilates with Vibro-Swing is an exercise that can promote independent living, fall prevention, and upper-extremity function in older adults by improving balance, strength, and physical function. Therefore, it can be recommended as a safe and appropriately intense exercise program for older adults who need to improve their balance, muscle strength, and joint proprioception.