This study first explored the demographics, physical fitness, and quality of life of sarcopenic older persons living in institutions. Secondly, the research studied the longitudinal effect of whole-body vibration on the sarcopenic older persons’ SMMI, physical fitness, and quality of life. According to the results of this research, after the intervention of the 12-week whole-body vibration, the SMMI and physical fitness improved significantly, respectively. Meanwhile, the quality of life of the older people in the pretest and posttest, the improvements were also founded.
Demographics, SMMI, physical fitness, and quality of life among sarcopenic older people
Adults aged older than 65 who lived in nursing homes and had sarcopenia were included in this study. The results showed that their average age was 82 years, indicating that sarcopenia is more common among older adults. Chang and Lin [
8] conducted a systematic literature review and meta-analysis; they determined that sarcopenia is common among older adults and that the risk of death is higher for older adults with sarcopenia than for those without sarcopenia. Meanwhile, this study showed that male older people outnumbered female older people, which matched the results of Wu et al. [
25] and Chien, Huang, and Wu [
26]. In addition, the study revealed that concerning the different diseases that the older adults had, the most common was diabetes, followed by hypertension. Kim et al. [
27] studied 145 older adults (aged 65 years or above) with sarcopenia and found that 73% and 56% of them had diabetes and hypertension, respectively. Landi et al. [
28] studied 40 older adults (aged 70 years or above) with sarcopenia and who lived in nursing homes, in which they found that 66% and 18% of them had hypertension and diabetes, respectively. Ishii et al. [
29] conducted a muscle mass study and studied older adults with sarcopenia and who lived in communities, in which they found that 48.5% and 13% of the older adults had hypertension and diabetes, respectively. These studies showed that older adults with sarcopenia experience chronic diseases and that comorbidity regularly exists.
In the present study, more than half of the older people had previously experienced fall(s), which supported the results obtained from related studies (i.e., older adults with sarcopenia have a higher risk of falling). Yamada et al. [
30] studied 414 older adults with sarcopenia and found that they were afraid of falling and had previously experienced fall(s), and that fall(s) is a sarcopenia-related factor. The frailty assessment of the present study showed that 88.2% of the older people were in the prefrail stage. According to Morley et al. [
31], sarcopenia reduces muscle strength and walking speed, which decrease mobility and overall calorie consumption as well as increase the severity of frailty. Scholars have pointed out that sarcopenia is a manifestation of frailty and that both sarcopenia and frailty are related to musculoskeletal system ageing [
32].
Concerning the physical fitness in the present study, the results matched the results obtained from related studies. In the study of 414 older adults with sarcopenia conducted by Yamada et al. [
30], the male and female participants had a walking speed of ≤1.0 m/s and < 0.8 m/s, respectively; the female participants outperformed the male participants in terms of their flexibility; and the male and female participants had a mean grip strength of 22 kg and 15 kg, respectively. Lee et al. [
33] conducted a sarcopenia-related study on older adults over the age of 65 and living in Yilan’s communities, and found that the male and female participants displayed a mean torso muscle mass of 22.6 ± 3.0 and 16.0 ± 2.2, respectively, and a mean grip strength of > 26 kg and > 18 kg, respectively; both the male and female participants had a walking speed of > 1.0 m/s. These studies showed that the participants of the present study had worse physical fitness than older adults with sarcopenia and living in communities did, which may be because of the differences in the environments between institutions and communities, and that the older people lacked regular exercises and physical activities.
Although EQ-5D-5 L, consists of a descriptive system and a visual analog scale (VAS), and it has been proven to demonstrate high reliability and validity when used to assess all patient types including those with stroke, sarcopenia, cardiovascular diseases, respiratory diseases, depression, diabetes, liver diseases, personality disorders, and arthritis [
34‐
38]. However, in 2015, Beaudart et al. developed a sarcopenia-specific quality of life questionnaire (the SarQoL) [
39]. In 2017, they tested the psychometric properties (i.e., reliability and validity) of the research instruments, and the results showed that the research instruments exhibited favorable discriminative power, high internal consistency, consistent construct validity, and excellent test–retest reliability [
40,
41]. Therefore, they recommended that the SarQoL questionnaire should be used to assess the quality of life of older adults with sarcopenia.
The longitudinal effect of whole-body vibration on SMMI, physical fitness, and quality of life
After 12 weeks of whole-body vibration, the SMMI became significantly higher than those before the intervention of whole-body vibration. These results supported the finding obtained from related studies. Machado, López, Gallego and Garatachea [
42] introduced a 10-week-long whole-body vibration to older adults with sarcopenia, in which the result showed that the experimental group participants’ muscle mass increased significantly after the 10-week-long whole-body vibration. Bogaerts et al. [
43] and Verschueren et al. [
44] found that whole-body vibration can improve bone density, enhance muscle quality, and lower body fat. However, some studies showed that whole-body vibration did not significantly improve the muscle mass of older adults with sarcopenia [
45‐
47]. The results of these studies differed from those of the present study because the vibration amplitude, vibration frequency, rest interval, and intervention duration varied across the studies.
In this study, after the12-week-long whole-body vibration intervention, the older people showed significant improvements in their physical fitness. These results matched that obtained from related studies. Wei et al. [
46] introduced a 12-week-long whole-body vibration to older adults with sarcopenia, where the results showed that the older adults’ five repeated sit-to-stand time and 10 m walking speed improved significantly after the intervention of the whole-body vibration. Delecluse, Roelants, and Verschueren [
48] indicated that whole-body vibration creates mechanical vibrations and promotes the synergist and antagonist muscle effect. Wu, Chen, and Chen [
49] studied the effect of a 6-week-long whole-body vibration and stretching on the functional fitness of 30 female older adults. Result indicates that whole-body vibration and stretching can significantly improve female older adults’ lower limb muscle strength, agility, balance while moving, and flexibility. Kawanabe et al. [
50] provided 67 older adults with a 2-month-long whole-body vibration, where they found that the whole-body vibration group’s walking pace and standing on one foot time increased significantly, and that the amount of time for them to walk 10 m decreased significantly. Bosco et al. [
51] examined the effect of whole-body vibration on improving older adults’ body composition and physical fitness, in which the results showed that it significantly improved their lower limb muscle strength and balance.
Regarding the older persons’ healthy quality of life index, it increased significantly after the intervention of the 12-week-long whole-body vibration. This result matched that of related studies. Álvarez-Barbosa et al. [
52] investigated the risk of falling, daily living activities, and healthy quality of life of 29 older adults living in an institution after the intervention of an 8-week-long whole-body vibration. The results showed statistically significant differences in the EQ-5D-5 L healthy quality of life index and the visual analog scale between the pretest and posttest. Studies that recruited different test populations also showed that whole-body vibration can improve the EQ-5D-5 L index. Baumbach et al. [
53] introduced a 6-week-long whole-body vibration to 60 participants. The participants’ mean EQ-5D-5 L index in the posttest was significantly higher than that of the pretest.
Limitations
The present study is the first-ever study to investigate the effect of whole-body vibration on improving the SMMI, physical fitness, and quality of life of sarcopenic older adults living in long-term care facilities, thereby marking the innovativeness and importance of this study. Nevertheless, this study still encountered a few limitations: First, this study conducted quasi-experimental, only single-group, pretest-posttest designs. Therefore, research can not reach allocation concealment procedure. Meanwhile, because this study was conducted in a quasi-experimental design, the external validity had limited explanatory power to make inferences. Second, because of safety reasons, we did not ask the older adults to fast. Instead, we measured their SMMI 3 h after they ate; hence, food consumption by the participants might have influenced the SMMI measurement. Third, this study adopted a quasi-experimental, single-group pretest-posttest design method, which better matched the real life situations of natural studies and featured less variable controls. However, such a method lacked a control group to enable a comparison between participants who underwent whole-body vibration and those who did not. Finally, this study required the participants to spend a relatively long time (i.e., an average of 30–40 min) to complete the study tools, which may have affected the participants’ willingness to complete them as well as the credibility of the results. Therefore, future studies may consider simplifying the study tools or providing the participants with a place to rest during repeated assessments to ensure that the study data better match actual experiment results.