The effect of whole body vibration exposure on muscle or bone morphology and function in older adults: A systematic review of the literature

Context and objective

The aim of this study was to examine the effect of whole body vibration (WBV), a novel exercise modality, on muscle or bone morphology and function in older adults.

Methods

A literature search of published randomised controlled trials (RCTs) was conducted using multiple databases and hand searching for study designs reporting the effects of WBV in older adults on any outcomes related to muscle function, or muscle or bone morphology. Concomitant exercise was only included if the control group performed the same exercise as the active WBV group, but without vibration.

Results

Six RCTs met the inclusion criteria of this review, three reporting measures of muscle only, two assessing bone measures only and one detailing measures of both bone and muscle. Study design varied greatly across the six trials and only six of 35 musculoskeletal outcomes analysed were statistically significant. All statistically significant improvements were of muscle function.

Conclusions

The published literature to date provides only weak support for the efficacy of WBV exposure for muscle function, muscle morphology, or bone architecture in older adults. Irregularities in study design and WBV protocols across the literature and poor quality trials contribute to this inconsistency, revealing the need for more uniformity in future trials. Future research should be more robust in design, include larger cohorts, longer interventions and standardisation of protocols. They should also investigate the optimal dose–response relationships and variation in vibration characteristics, to determine the true efficacy, clinical relevance, and underlying mechanisms of muscle and bone adaptations.     

Effect of whole body vibration exercise on muscle strength and proprioception in females with knee osteoarthritis

The purpose of this study was to assess the effect of whole body vibration (WBV) exercise on muscle strength and proprioception in female patients with osteoarthritis in the knee (knee-OA). A single blinded, randomised, controlled trial was performed in an outpatient clinic on 52 female patients diagnosed with knee-OA (mean age 60.4 years ± 9.6). They were randomly assigned to one of 3 groups: 1. WBV-exercise on a stable platform (VibM; n = 17 (mean age, 61.5 ± 9.2)), WBV-exercise on a balance board (VibF; n = 18 (mean age, 58.7 ± 11.0)), or control group (Con; n = 18 (mean age, 61.1 ± 8.5)).The WBV groups trained twice a week for 8 weeks, with a progressively increasing intensity. The WBV groups performed unloaded static WBV exercise.The following were measured: knee muscle strength (extension/flexion) and proprioception (threshold for detection of passive movement (TDPM)). Self-reported disease status was measured using WOMAC.It was found that muscle strength increased significantly (p < 0.001) in VibM compared to Con. Isometric knee-extension significantly increased (p = 0.021) in VibM compared to Con. TDPM was significantly improved (p = 0.033) in VibF compared to Con, while there was a tendency (p = 0.051) for VibM to perform better compared to Con. There were no effects in the self-reported disease status measures.This study showed that the WBV-exercise regime on a stable platform (VibM) yielded increased muscle strength, while the WBV-exercise on a balance board (VibF) showed improved TDPM. The WBV-exercise is a time-saving and safe method for rehabilitation of women with knee-OA.     

The effect of muscle vibration on human position sense during movements controlled by lengthening muscle contraction

Summary Muscle vibration studies suggest that during voluntary movement limb position is coded by muscle spindle information derived from the lengthening, antagonist muscle. However, these investigations have been limited to movements controlled by shortening contractions. This study further examined this property of kinesthesia during movements controlled by lengthening contraction. Subjects performed a horizontal flexion of the right forearm to a mechanical stop randomly positioned at 30, 50 and 70° from the starting position. The movement was performed against a flexor load (1 kg) requiring contraction of the triceps muscle. Vision was occluded and movements were performed under three conditions: no vibration, vibration of the right biceps and vibration of the right triceps. The perceived position of the right forearm was assessed by instructing subjects to simultaneously match the right limb position with the left limb. Vibration of the shortening biceps muscle had no effect on limb matching accuracy. However, triceps vibration resulted in significant overestimation of the vibrated limb position (10–13°). The variability in movement distance was uninfluenced by muscle vibration. During movements controlled by lengthening contraction, there is a concurrent gamma dynamic fusimotor input that would enhance primary afferent discharge. Despite this additional regulating input to the muscle spindle, it appears that muscle spindle information from the lengthening muscle is important for the accurate perception of limb movement and/or position.     

Influence of muscle activation dynamics on reaction time in the elderly

The aim of this investigation was to determine whether age-related changes in the dynamics of muscle activation were, in part, responsible for longer reaction times (RT) in the elderly. A group of 12 young (mean age, 20.6 years) and 12 elderly (mean age, 64.3 years) women performed a series of ballistic forearm supination movements in response to an auditory stimulus while using a simple reaction time test. Surface electromyographic waveforms from biceps brachii (agonist) and pronator teres (antagonist) muscles were recorded, together with the angle-time curves representing the motion of the forearm, on to an IBM compatible microcomputer. The results showed that an age-related increase (P<0.05) in motor reaction time (MRT) contributed to longer RT in the elderly. In addition, the longer (P<0.05) MRTs in the elderly were associated with a significantly slower rate (P<0.05) of biceps brachii muscle activation and a significantly increased proportion (P<0.05) of the initial biceps brachii muscle burst required to initiate the movement. This data suggested that an important part of the slowing of motor behaviour, commonly observed with increasing age, may be due to either decreases in the ability of aged skeletal muscle to rapidly generate tension or to a reduction in motor drive.     

The influence of primary health care professionals in encouraging exercise and physical activity uptake among White and South Asian older adults: Experiences of young older adults

Objective

To explore the influence of primary health care professionals in increasing exercise and physical activity among 60–70-year-old White and South Asian community dwellers.

Method

Fifteen focus groups and 40 in-depth interviews with community dwelling White and South Asian 60–70-year olds. The sample was selected to include people with very different experiences of participation and non-participation in exercise and physical activity. Data were analysed using framework analysis.

Results

Primary health care professionals’ advice and support was found to be a motivator to the initiation of exercise and physical activity. However, this was usually in relation to advice on weight reduction, cardiac conditions and mobility issues, but not generally to improve or increase activity levels. An underlying attitude of genuine interest and empathy was valued and shaped decisions about initiating and/or increasing activity levels.

Conclusion

Primary health care professionals should be encouraged to show interest and empathy with older people about the positive benefits of exercise and physical activity to them individually. This advice needs to be tailored to the older adult's symptoms.

Practice implications

Primary health care professionals need to be able to provide specific advice as to the quantity (frequency, duration, intensity and type) of exercise or physical activity to undertake. Practitioners need to listen to their patients’ needs, show empathy and avoid ageism during consultations.     

静态拉伸与下肢肌力锻炼在老年平衡能力中的意义

背景：进入老龄化社会后,通过改善老年人的平衡能力来预防跌倒,减少骨折等意外伤害的发生已经受到了各方面的广泛重视。 目的：设计适合老年人的静态拉伸和下肢肌力相结合的运动方案并借以研究其对老年人平衡能力的影响。 方法：对28名符合入选标准的老年人进行为期3个月的静态拉伸和下肢肌力训练,3次/周,60 min/次。训练前后分别用PRO-KIN 平衡仪进行睁、闭眼双脚站立静态平衡能力评估;用闭目原地踏步和反复坐起测试进行动态平衡能力和下肢肌力的评估。对比分析前后两次测试结果。 结果与结论：在睁眼状态下,锻炼前后的压力中心的X轴平均坐标、运动椭圆面积差异均有非常显著性意义(P < 0.01);左右方向平均运动速度差异有显著性意义(P < 0.05);闭目原地踏步测试脚触线时间和反复坐起时间均差异有非常显著性意义(P < 0.01)。结果表明,静态拉伸与下肢肌力锻炼相结合能够有效提高老年人的平衡能力,可作为预防老年人跌倒的有效锻炼方式。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Platform accelerations of three different whole-body vibration devices and the transmission of vertical vibrations to the lower limbs

Physical whole-body vibration (WBV) exercises become available at various levels of intensity. In a first series of measurements, we investigated 3-dimensional platform accelerations of three different WBV devices without and with three volunteers of different weight (62, 81 and 100 kg) in squat position (150° knee flexion). The devices tested were two professional devices, the PowerPlate and the Galileo-Fitness, and one home-use device, the PowerMaxx. In a second series of measurements, the transmission of vertical platform accelerations of each device to the lower limbs was tested in eight healthy volunteers in squat position (100° knee flexion). The first series showed that the platforms of two professional devices vibrated in an almost perfect vertical sine wave at frequencies between 25–50 and 5–40 Hz, respectively. The platform accelerations were slightly influenced by body weight. The PowerMaxx platform mainly vibrated in the horizontal plane at frequencies between 22 and 32 Hz, with minimal accelerations in the vertical direction. The weight of the volunteers reduced the platform accelerations in the horizontal plane but amplified those in the vertical direction about eight times. The vertical accelerations were highest in the Galileo (15 units of g) and the PowerPlate (8 units of g) and lowest in the PowerMaxx (2 units of g). The second series showed that the transmission of vertical accelerations at a common preset vibration frequency of 25 Hz were largest in the ankle and that transmission of acceleration reduced 10 times at the knee and hip. We conclude that large variation in 3-dimensional accelerations exist in commercially available devices. The results suggest that these differences in mechanical behaviour induce variations in transmissibility of vertical vibrations to the (lower) body.     

Effects of vibration and resistance training on neuromuscular and hormonal measures

The aim was to study whether whole body vibration (WBV) combined with conventional resistance training (CRT) induces a higher increase in neuromuscular and hormonal measures compared with CRT or WBV, respectively. Twenty-eight young men were randomized in three groups; squat only (S), combination of WBV and squat (S+V) and WBV only (V). S+V performed six sets with eight repetitions with corresponding eight repetition maximum (RM) loads on the vibrating platform, whereas S and V performed the same protocol without WBV and resistance, respectively. Maximal isometric voluntary contraction (MVC) with electromyography (EMG) measurements during leg press, counter movement jump (CMJ) measures (mechanical performance) including jump height, mean power (P _mean), peak power (P _peak) and velocity at P _peak (V _ppeak) and acute hormonal responses to training sessions were measured before and after a 9-week training period. ANOVA showed no significant changes between the three groups after training in any neuromuscular variable measured [except P _mean, S higher than V (P<0.05)]. However, applying t tests within each group revealed that MVC increased in S and S+V after training (P<0.05). Jump height, P _mean and P _peak increased only in S, concomitantly with increased V _ppeak in all groups (P<0.05). Testosterone increased during training sessions in S and S+V (P<0.05). Growth hormone (GH) increased in all groups but S+V showed higher responses than S and V (P<0.05). Cortisol increased only in S+V (P<0.05). We conclude that combined WBV and CRT did not additionally increase MVC and mechanical performance compared with CRT alone. Furthermore, WBV alone did not increase MVC and mechanical performance in spite of increased GH.     

Physical activity monitoring by use of accelerometer-based body-worn sensors in older adults: a systematic literature review of current knowledge and applications

Objectives

To systematically review the literature on physical activity variables derived from body-worn sensors during long term monitoring in healthy and in-care older adults.

Methods

Using pre-designed inclusion and exclusion criteria, a PubMed search strategy was designed to trace relevant reports of studies. Last search date was March 8, 2011.

Study selection

Studies that included persons with mean or median age of >65 years, used accelerometer-based body-worn sensors with a monitoring length of >24 h, and reported values on physical activity in the samples assessed.

Results

1403 abstracts were revealed and 134 full-text papers included in the final review. A variety of variables derived from activity counts or recognition of performed activities were reported in healthy older adults as well as in in-care older adults. Three variables were possible to compare across studies, level of Energy Expenditure in kcal per day and activity recognition in terms of total time in walking and total activity. However, physical activity measured by these variables demonstrated large variation between studies and did not distinguish activity between healthy and in-care samples.

Conclusion

There is a rich variety in methods used for data collection and analysis as well as in reported variables. Different aspects of physical activity can be described, but the variety makes it challenging to compare across studies. There is an urgent need for developing consensus on activity monitoring protocols and which variables to report.     

Kinaesthetic role of muscle afferents in man,studied by tendon vibration and microneurography

Summary The characteristics of vibration-induced illusory joint movements were studied in healthy human subjects. Unseen by the subject, constant frequency vibration trains applied to the distal tendon of the Triceps or Biceps induced an almost constant velocity illusory movement of the elbow whose direction corresponded to that of a joint rotation stretching the vibrated muscle. Vibration trains of the same duration and frequency applied alternatively to the Biceps and Triceps evoked alternating flexion-extension illusory movements.During successive application of vibration trains at frequencies from 10 to 120 Hz, the perceived velocity of the illusory movements increased progressively from 10 to 70–80 Hz, then decreased from 80 to 120 Hz. The maximal perceived velocity was three times higher during alternating vibration of the Biceps and Triceps than during single muscle stimulation.Unit activity from 15 muscle spindle primary endings and five secondary endings located in Tibialis anterior and Extensor digitorum longus muscles were recorded using microneurography in order to study their responses to tendon vibration and passive and active movements of the ankle.Primary endings were all activated by low amplitude tendon vibration (0.2–0.5 mm) previously used to induce illusory movements of the elbow. The discharge of some was phase-locked with the vibration cycle up to 120 Hz, while others responded one-to-one to the vibration cycle up to 30–50 Hz, then fired in a sub-harmonic manner at higher frequencies. Secondary endings were much less sensitive to low amplitude tendon vibration.Primary and secondary ending responses to ramp and sinusoïdal movements of the ankle joint were compared. During the movement, the primary ending discharge frequency was almost constant, while the secondary ending activity progressively increased. During ankle movements the primary ending discharge appeared mainly related to velocity, while some secondary activities seemed related to both movement velocity and joint angle position.Muscle spindle sensory ending responses to active and passive ankle movements stretching the receptor-bearing muscle (plantar flexion) were qualitatively and quantitatively similar. During passive reverse movements (dorsiflexion) most of the sensory endings stopped firing when their muscle shortened. Active muscle shortening (isotonic contraction) modulated differently the muscle spindle sensory ending discharge, which could stop completely, decrease or some times increase during active ankle dorsiflexion. During isometric contraction most of the muscle spindle sensory endings were activated.The characteristics of the vibration-induced illusory movements and the muscle spindle responses to tendon vibration and to active and passive joint movements strengthened the possibility of the contribution of primary endings to kinaesthesia, as suggested by several previous works. Moreover, the present results led us to attribute to proprioception in the muscle stretched during joint movement a predominant, but not exclusive, role in this kind of perception.     

The effect of exercise training on glycogen,glycogen synthase and phosphorylase in muscle and liver

Summary It is thought that exercise training in both man and the rat results in a protective effect against the depletion of carbohydrate stores during exercise (glycogen-sparing). However there has been no comprehensive study of the effects of training on glycogen anabolic and catabolic enzymes with liver or muscle. The aim of this study was to examine whether changes in these enzymes occur and whether these changes may provide an explanation for the glycogen-sparing which results from exercise training.Male rats were trained by a treadmill running program at three different workloads. In addition, there were three control groups: free eating (SF), food restricted (SR), and one SF with a single bout of exercise prior to sacrifice.Exercise training was associated with a 60–150% increase in glycogen synthase and phosphorylase and a 50–70% increase in glycogen content in soleus, an intermediate muscle, but not in extensor digitorum longus (EDL), a white muscle nor in liver. The increase in glycogen synthase and phosphorylase in intermediate muscle was proportional to the degree of training and there was a significant correlation between glycogen content, glycogen synthase, and phosphorylase activity in intermediate muscle. Cytochrome c oxidase activity, an indicator of respiratory capacity, increased 50% in gastrocnemius of trained rats and was significantly correlated with glycogen synthase and phosphorylase in soleus.These results indicate a significant effect of exercise training on glycogen anabolic and catabolic enzymes in intermediate muscle, with no significant effects in white muscle or liver. The changes do not provide an explanation for glycogen-sparing, but are consistent with improved capacity of intermediate muscle for rapid glycogen mobilisation and repletion.     

The effects of wrist muscle vibration on human voluntary elbow flexion-extension movements

Summary The effect of forearm muscle tendon vibration during alternating step flexion-extension movements about the elbow was studied in normal humans. In one experiment, a vibrator was mounted over either the forearm flexor or the extensor muscle. In a second experiment, a vibrator was mounted over either the forearm muscle or the biceps muscle. In both experiments, vibration was applied either to a single muscle or simultaneously to both muscles during elbow flexion-extension movements. After a period of practice, subjects learned the required movements and were able to make them with their eyes closed. Application of vibration to the forearm and the biceps muscle during extension movements produced an undershoot of the required end movement position. Moreover, application of high frequency vibration (100 Hz) to the forearm extensor and flexor muscle produced an overshoot of the required end-movement position. The observed results are consistent with vibration induced activation of muscle spindle receptors not only in the lengthening muscle during movement but also in the forearm muscles. It is suggested that the pattern of distribution of muscle spindle afferent from the forearm muscle onto -motoneurons of muscles acting at the elbow has played an important role of alternating step flexion-extension movements.     

Effect of concurrent aerobic and resistance circuit exercise training on fitness in older adults

The purpose of this study was to determine the physiological effects of a programmed accommodating circuit exercise (PACE) program consisting of aerobic exercise and hydraulic-resistance exercise (HRE) on fitness in older adults. Thirty-five volunteers were randomly divided into two groups [PACE group (PG) 8 men and 10 women, 68.3 (4.9) years, and non-exercise control group (CG) 7 men and 10 women, 68.0 (3.4) years). The PG participated in a 12-week, 3 days per week supervised program consisting of 10 min warm-up and 30 min of PACE (moderate intensity HRE and aerobic movements at 70% of peak heart rate) followed by 10 min cool-down exercise. PACE increased (P<0.05) oxygen uptake (O₂) at lactate threshold [PG, pre 0.79 (0.20) l min^–1, post 1.02 (0.22) l min^–1, 29%; CG, pre 0.87 (0.14) l min^–1, post 0.85 (0.15) l min^–1, –2%] and at peak O₂ [PG, pre 1.36 (0.24) l min^–1, post 1.56 (0.28) l min^–1, 15%; CG, pre 1.32 (0.29) l min^–1, post 1.37 (0.37) l min^–1, 4%] in PG measured using an incremental cycle ergometer. Muscular strength evaluated by a HRE machine increased at low to high resistance dial settings for knee extension (9–52%), knee flexion (14–76%), back extension (18–92%) and flexion (50–70%), chest pull (6–28%) and press (3–17%), shoulder press (18–31%) and pull (26–85%), and leg press (21%). Body fat (sum of three skinfolds) decreased (16%), and high-density lipoprotein cholesterol (HDLC) increased (10.9 mg dl^–1) for PG. There were no changes in any variables for CG. These results indicate that PACE training incorporating aerobic exercise and HRE elicits significant improvements in cardiorespiratory fitness, muscular strength, body composition, and HDLC for older adults. Therefore, PACE training is an effective well-rounded exercise program that can be utilized as a means to improve health-related components of fitness in older adults.     

The effect of pedaling frequency on glycogen depletion rates in type I and type II quadriceps muscle fibers during submaximal cycling exercise

Summary This study was conducted to determine whether the pedaling frequency of cycling at a constant metabolic cost contributes to the pattern of fiber-type glycogen depletion. On 2 separate days, eight men cycled for 30 min at approximately 85% of individual aerobic capacity at pedaling frequencies of either 50 or 100 rev·min^–1. Muscle biopsy samples (vastus lateralis) were taken immediately prior to and after exercise. Individual fibers were classified as type I (slow twitch), or type II (fast twitch), using a myosin adenosine triphosphatase stain, and their glycogen content immediately prior to and after exercise quantified via microphotometry of periodic acid-Schiff stain. The 30-min exercise bout resulted in a 46% decrease in the mean optical density (D) of type I fibers during the 50 rev·min^–1 condition [0.52 (0.07) to 0.28 (0.04)D units; mean (SEM)] which was not different (P>0.05) from the 35% decrease during the 100 rev · min^–1 condition [0.48 (0.04) to 0.31 (0.05)D units]. In contrast, the meanD in type II fibers decreased 49% during the 50 rev·min^–1 condition [0.53 (0.06) to 0.27 (0.04) units]. This decrease was greater (P<0.05) than the 33% decrease observed in the 100 rev·min –1 condition [0.48 (0.04) to 0.32 (0.06) units). In conclusion, cycling at the same metabolic cost at 50 rather than 100 rev·min^–1 results in greater type II fiber glycogen depletion. This is attributed to the increased muscle force required to meet the higher resistance per cycle at the lower pedal frequency. These data are consistent with the view that force development as opposed to velocity of contraction determines the degree of type II fiber recruitment when the metabolic cost of exercise is held constant.     

The added value of therapist communication on the effect of physical therapy treatment in older adults; a systematic review and meta-analysis

Objective

Lower physical activity levels in older adults are associated with increased co-morbidities and disability. Physical therapists have a critical role in facilitating increases in physical activity. The communication they use may impact their effectiveness. This study investigates the additional value of therapist’s communication during physical therapy on older adults’ physical activity levels.

Types of exercise and training duration on depressive symptoms among older adults in long-term care facilities

BackgroundDepression is associated with a greater risk of disability, cognitive impairment, and suicide. Older adults in long-term care facilities (LTCFs) are more likely to develop depression due to changes in family roles and separation from family members. The aim of this study was to synthesize and analyze the effects of different types of exercise and training duration on depressive symptoms of older adults in LTCFs.MethodsRelevant peer-reviewed journal articles published in English were identified through a search of six electronic databases up to June 2021.ResultsA total of 25 studies were included in the systematic review and 22 in the meta-analysis. The results of meta-analysis showed that exercise interventions reduced depression in cognitively intact older adults and in cognitively impaired older adults. Both exercising less than 150 min per week or more than 150 min per week, reduced depressive symptoms of older adults. In terms of exercise types, mind-body exercises, exergames, and strength training reduced depressive symptoms.ConclusionExercise has a positive effect on reducing depressive symptoms with mind-body exercises, exergames, and strength training producing the best effect. Regardless of cognitive impairment, older adults in LTCFs benefited from exercise in reducing depressive symptoms.     

Underrepresentation of older adults in clinical trials on COVID-19 vaccines: A systematic review

During the COVID-19 pandemic older subjects have been disproportionately affected by the disease. Vaccination is a fundamental intervention to prevent the negative consequences of COVID-19, but it is not known if the needs and vulnerabilities of older people are adequately addressed by their inclusion in randomized clinical trials (RCTs) evaluating the efficacy of vaccines for COVID-19. Given this background, we aimed to evaluate if current and ongoing phase II-III RCTs evaluating the efficacy of COVID-19 vaccines included a representative sample of older people. A systematic literature search in PubMed and Clinicaltrials.gov was performed until May 01st, 2021. Among 474 abstracts initially retrieved, 20 RCTs (ten already published, ten ongoing) were included. In the ten studies already published, the mean age of participants was 45.2 ± 11.9 years and only 9.83% of the participants were more than 65 years, 1.66% more than 75 years and less than 1% (0.55%) more than 85 years. In the ten ongoing RCTs, many of the studies aimed at including participants older than 18 years, with one study including participants between 18 and 84 years, and two between 21 and 100 years. In conclusion, our systematic review demonstrates that in published and ongoing phase II-III randomized clinical trials evaluating the efficacy of COVID-19 vaccines only a tiny fraction of the most vulnerable group of older people was included, although they clearly were the first population that had to be vaccinated.