The influence of vibration type, frequency, body position and additional load on the neuromuscular activity during whole body vibration

The merit of superimposed vibration for flexibility and passive stiffness: A systematic review with multilevel meta-analysis

BACKGROUND

Due to its high relevance in sports and rehabilitation, the exploration of interventions to further optimize flexibility becomes paramount. While stretching might be the most common way to enhance range of motion, these increases could be optimized by imposing an additional activation of the muscle, such as mechanical vibratory stimulation. While several original articles provide promising findings, contradictory results on flexibility and underlying mechanisms (e.g., stiffness), reasonable effect size (ES) pooling remains scarce. With this work we systematically reviewed the available literature to explore the possibility of potentiating flexibility, stiffness, and passive torque adaptations by superimposing mechanical vibration stimulation.

METHODS

A systematic search of 4 databases (Web of Science, MEDLINE, Scopus, and Cochrane Public Library) was conducted until December 2023 to identify studies comparing mechanical vibratory interventions with passive controls or the same intervention without vibration (sham) on range of motion and passive muscle stiffness in acute (immediate effects after single session) and chronic conditions (multiple sessions over a period of time). ES pooling was conducted using robust variance estimation via R to account for multiple study outcomes. Potential moderators of effects were analyzed using meta regression.

RESULTS

Overall, 65 studies (acute: 1162 participants, chronic: 788 participants) were included. There was moderate certainty of evidence for acute flexibility (ES = 0.71, p < 0.001) and stiffness (ES = -0.89, p = 0.006) effects of mechanical vibration treatments vs. passive controls without meaningful results against the sham condition (flexibility: ES = 0.20, p < 0.001; stiffness: ES = -0.19, p = 0.076). Similarly, moderate certainty of evidence was found for chronic vibration effects on flexibility (control: ES = 0.64, p = 0.043; sham: ES = 0.65, p < 0.001). Lack of studies and large outcome heterogeneity prevented ES pooling for underlying mechanisms.

CONCLUSION

Vibration improved flexibility in acute and chronic interventions compared to the stand-alone intervention, which can possibly be attributed to an accumulated mechanical stimulus through vibration. However, studies on biological mechanisms are needed to explain flexibility and stiffness effects in response to specific vibration modalities and timing.

Unveiling whole body vibration squat intensity insight from oxygen consumption and heart rate response

This study explored the effects of training weight and amplitude in whole-body vibration (WBV) on exercise intensity, indicated by oxygen consumption (VO2) and heart rate. In LOAD-study: ten participants performed squats under non-WBV and WBV (30 Hz 2 mm) conditions at 0%, 40%, and 80% bodyweight (BW). In AMPLITUDE-study: eight participants performed squats under non-WBV, low-amplitude WBV (30 Hz 2 mm), and high-amplitude WBV (30 Hz 4 mm) conditions with 0% and 40%BW. heart rate and VO2 were continuously recorded. Metabolic equivalents (METs) for WBV squats with 0-40% BW were ~ 3.8-5.3, and ~ 7.3 for 80% BW. LOAD-study presented a significant vibration × training weight interaction effect for in-exercise VO2 (F = 3.171, P = 0.05, ηp2 = 0.105) and post-exercise VO2 (F = 4.156, P = 0.021, ηp2 = 0.133). In-exercise VO2 of 80%BW squat (P < 0.001) and post-exercise VO2 of both 40% (P = 0.049) and 80%BW squat (P < 0.001) under WBV were significantly higher than those under non-WBV. AMPLITUDE-study presented no significant amplitude × training weight interaction effect for VO2 and heart rate (P > 0.05). WBV squats are moderate-to-vigorous intensity exercise. 30 Hz 2 mm WBV is sufficient for evoking superior oxygen consumption during and after exercise under certain training weight, the response of heart rate to WBV was less pronounced. Increasing training weight could elicit greater oxygen consumption and heart rate under WBV condition.

The Clinical Utility of Whole Body Vibration: A Review of the Different Types and Dosing for Application in Metabolic Diseases

Whole body vibration (WBV) is an innovative exercise mimetic that utilizes a vibrating platform to transmit mechanical vibrations throughout the body. WBV has been a popular area of research in recent years due to its potential physiological and therapeutic benefits in both health and disease. The utility of WBV is rooted in the various parameters (i.e., frequency, amplitude, duration) that affect the overall dose of vibration delivered to the body. Each type of WBV, coupled with these aforementioned parameters, should be considered when evaluating the use of WBV in the clinical setting. Thus, the purpose of this review is to provide an overview of recent literature detailing the different types of WBV, the various parameters that contribute to WBV efficacy, and the evidence of WBV in metabolic disease. A systematic search was conducted using Medline, Embase, Cochrane, CINAHL, and PubMed. All types of study designs were considered, with exclusions made for animal studies, duplicates, and study protocols without data. Thirty-four studies were included. In conclusion, as a modern exercise mimetic with therapeutic potential for metabolic diseases, understanding the interplay between the types and dosing of WBV is critical for determining its utility and efficacy. Further studies are certainly needed to elucidate the full therapeutic potential of WBV in metabolic diseases.

Acute neuromuscular responses to whole-body vibration in healthy individuals: A systematic review

Whole-body vibration (WBV) training has been employed alongside conventional exercise like resistance training to enhance skeletal muscle strength and performance. This systematic review examines the evidence regarding the effect of WBV on muscle activity, strength, and performance in healthy individuals. The Academic Search Ultimate, CINAHL, Cochrane CENTRAL, PubMed, ProQuest One Academic and SCOPUS databases were searched from 1990 to April 2023 to retrieve relevant studies. Methodological quality was assessed using the Modified Downs and Black checklist, while the level of evidence was evaluated through the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool. Even though the quality of the included studies was moderate to high, the level of evidence was very low owing to serious concerns with three or more GRADE domains (risk of bias, inconsistency, indirectness, imprecision, and publication bias) for each outcome of interest across studies. The review suggests that in WBV training, using moderate to high vibration frequencies (25-40 Hz) and high magnitudes (3-6 mm) can enhance muscle activation and strength in pelvis and lower limb muscles. However, findings regarding WBV effect on muscle performance measures were inconsistent. Future research with robust methodology is necessary in this area to validate and support these findings.

Intervention Hypothesis for Training with Whole-Body Vibration to Improve Physical Fitness Levels: An Umbrella Review

Whole-body vibration (WBV) is a training modality, and it seems to be a safe and efficient exercise especially to improve different aspects of physical fitness in different populations. The protocols for WBV are still not standardized. The difficulty in comparing the data confuses the real efficacy of this instrument. Consequently, the objective of this umbrella review is to analyze the protocols previously adopted and eventually to propose a standard operating procedure for WBV training. Systematic review and meta-analysis of randomized controlled trials on WBV were searched on the electronic databases PubMed, Web of Science, and Scopus until 18 March 2024. A quality assessment of the studies included has been performed. A total of 20 studies were included in this umbrella review and frequency, magnitude, and amplitude intensity data were recorded. Detailed information about the protocols (static or dynamic exercises, barefoot or with shoes, intensity duration, weekly frequency, and vibration characteristics) was also collected. WBV presents widely different protocols. Consequently, a standard operating procedure has not been proposed for WBV training. A hypothesis of intervention was instead written in which parameters for frequency, amplitude, acceleration, and training mode were proposed.

Effectiveness of Proprioceptive Body Vibration Rehabilitation on Motor Function and Activities of Daily Living in Stroke Patients with Impaired Sensory Function

Stroke patients experience impaired sensory and motor functions, which impact their activities of daily living (ADL). The current study was designed to determine the best neurorehabilitation method to improve clinical outcomes, including the trunk-impairment scale (TIS), Berg balance scale (BBS), Fugl-Meyer assessment (FMA), and modified Barthel index (MBI), in stroke patients with impaired sensory function. Forty-four stroke survivors consistently underwent proprioceptive body vibration rehabilitation training (PBVT) or conventional physical therapy (CPT) for 30 min/session, 5 days a week for 8 weeks. Four clinical outcome variables-the FMA, TIS, BBS, and MBI-were examined pre- and post-intervention. We observed significant differences in the FMA, BBS, and MBI scores between the PBVT and CPT groups. PBVT and CPT showed significant improvements in FMA, BBS, TIS, and MBI scores. However, PVBT elicited more favorable results than CPT in patients with stroke and impaired sensory function. Collectively, this study provides the first clinical evidence of optimal neurorehabilitation in stroke patients with impaired sensory function.

Effectiveness of whole-body vibration in patients with cerebral palsy: A systematic review and meta-analysis

BACKGROUND

This study examined the effects of systemic vibration exercises on cerebral palsy patients.

METHODS

Literature published in Cumulated Index to Nursing and Allied Health Literature (CINAHL), Cochrane library, Embase, Physiotherapy Evidence Database (PEDro), and PubMed was reviewed. A total of 2978 studies were initially retrieved. After further reading of the full texts 17 articles were finally included. A quality assessment of the included studies was conducted using the risk of bias (RoB) 2.0, and the Funnel plot and the Egger test were conducted to confirm the publication bias. Subgroup analysis was carried out according to the dependent variables, the international classification of functioning, disability, and health (ICF), frequency, treatment period and age.

RESULTS

The overall effect size of homogeneity was 0.474 (CI = 0.148-0.801). The analysis of the dependent variables showed the following order of the effect size: balance, muscle strength, spasticity, bone density, range of motion of the joint, gait function, and motor function. In the ICF classification, the effect size was observed to follow the order of body structure and function, activity, and participation. The effect size in the intervention according to the treatment period showed the following order: 7 to 12 weeks, 1 to 6 weeks, and 14 to 24 weeks. The age-dependent classification showed the following order in the effect size: school age, adolescent and adult, and infant and school age.

CONCLUSIONS

Systemic vibration is the most effective intervention to improve the balance and gait in patients with cerebral palsy and improve the body structure and function according to the ICF.

Effects of whole-body vibration training in static and dynamic semi-squat patterns on the lower limb muscle activity

The decline in physical function and the deterioration of the neuromusculoskeletal system in older people can easily lead to reduced muscle strength and slower mobility in the joints of the lower limbs, increasing the incidence of chronic diseases such as muscle wasting disorders, osteoporosis, debilitation and fall and fracture. It may also affect the quality of life and functional independence of older people, and in serious cases, even directly threaten their health. This study was conducted to determine the differences in lower limb muscle activation characteristics between static semi-squat (SSS) and dynamic semi-squat (DSS) training in middle-aged and old women at different frequencies and amplitudes and to explore a personalized whole-body vibration (WBV) training instruction program suitable for them. Fifteen healthy middle-aged and old women (60.8 ± 4.18 years old) were recruited for SSS and DSS WBV training. Their muscle activity of the rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF) and gastrocnemius (GS) were calculated using the BTS FreeEMG300 wireless surface electromyography (EMG), which participants were completed that the two different contraction patterns of squats on WBV training. The knee flexion was maintained at 45° while the subjects were performing the SSS training, while during the DSS training, the knee flexion fluctuates between 10° and 45°. The SSS exercise requires the subject to remain stationary in the squatting position and the DSS to be performed at a rhythm of 4 s/repetition, with 2 s of squatting, 1 s of standing up, and 1 s intervals. The vibration frequencies and amplitudes were changed to the WBV training intensity, and the vibration frequencies were set to 0 Hz, 30 Hz and 40 Hz, and the amplitudes were set to 0 mm, 2 mm and 4 mm. Each subject is randomised to participate in WBV training with 5 combinations of frequency and amplitude in both static and dynamic semi-squat patterns. These were 0 Hz 0 mm, 30 Hz 2 mm, 30 Hz 4 mm, 40 Hz 2 mm, 40 Hz 4 mm for the static and dynamic demi-squat patterns of WBV training. A two-way repeated measures ANOVA was applied to compare the changes in surface EMG of the lower limb muscles in different modes of SSS and DSS with WBV training. (1) Our results showed significantly interaction effects in the frequency × amplitude of root mean square (EMGrms) in GS (P < 0.05), while no significant differences were observed in the interaction effects of SSS/DSS patterns, frequencies and amplitude of RF, VM, VL and BF (P > 0.05). (2) Comparisons between groups showed that the EMGrms of the RF were significantly higher for the DSS than the SSS (P < 0.05). Additionally, the EMGrms of VL and BF at 30 Hz and 40 Hz were greater than 0 Hz (P < 0.05). Also, The EMGrms at 4 mm for the VM, VL and BF were significantly higher than 0 mm, the EMGrms at 4 mm for the VM and VL were significantly higher than 2 mm (P < 0.05), and the EMGrms at 2 mm of VL and BF were significantly higher than 0 mm (P < 0.05). (3) The results showed that WBV stimulation significantly increased the EMGrms of the GS in the SSS compared with the vibration free semi-squat alone (P < 0.05). However, there were no significant differences between WBV training protocols for SSS patterns with different frequencies and amplitudes (frequencies and amplitudes not were 0 Hz and 0 mm) (P > 0.05). Comparison of EMGrms for WBV training of the GS in DSS patterns showed that 40 Hz/4 mm was significantly higher than 0 Hz/0 mm (P < 0.05), but there was no significant difference between the remaining vibration conditions (P > 0.05). WBV training for DSS can significantly improve the activation of the RF compared to SSS pattern. Compared with no vibration, WBV could significantly improv the activity of the lower limb muscles. Additionally, an increase in amplitude from 2 to 4 mm could significantly improve VM and VL activation, while no significant improvement on lower limb muscle activation was observed for increasing vibration frequency from 30 to 40 Hz.

Acute effects of blood flow restriction with whole-body vibration on sprint, muscle activation and metabolic accumulation in male sprinters

Purpose: The aim of this study was to explore the acute effects of Blood Flow Restriction Training (BFRT), Whole-Body Vibration (WBV), and BFRT + WBV on the 20 m sprint, muscle activation, and metabolic accumulation in male sprinters.

Method: Sixteen male sprinters randomly performed BFRT, WBV, or BFRT + WBV interventions with 72 h intervals. Electromyography (EMG) signals were collected before and during interventions. Fingertip blood was taken before, immediately after, and 15 min after the intervention. 20 m sprint was performed before and 3 min after the intervention.

Results: 1) 0–10m and 0–20 m sprint performance were significantly improved after WBV and BFRT + WBV interventions (p &lt; 0.05), 0–20 m sprint performance was significantly improved after all three interventions (p &lt; 0.05), 2) After BFRT + WBV intervention, the EMG amplitude of the vastus lateralis and soleus were significantly improved. Greater increases in EMG activity of the tibialis anterior muscle (p &lt; 0.05)and blood lactate (p &lt; 0.05)were observed following BFRT intervention compared to BFRT + WBV intervention.

Conclusion: For sprint performance, BFRT and WBV had similar post-activation enhancement effects to BFRT + WBV, and the metabolic accumulation immediately following the BFRT were higher than that following BFRT + WBV in male sprinters.

The Effects of Vibration Exposure on Lower-Limb Extensor Muscles' Stiffness, Elasticity, and Strength Responses in Untrained Young Individuals: A Randomized Controlled Trial

OBJECTIVES

The whole-body vibration (WBV) effects on muscle strength show inconsistent results. Moreover, there is no study about the WBV effect on stiffness, elasticity, and muscle strength. Therefore, the study aimed to examine the effect of WBV exposure with static squat posture on the stiffness, elasticity, and strength of the lower-limb extensor muscles.

MATERIAL AND METHODS

Forty healthy untrained young adults were divided into WBV and control groups. The experimental group received WBV exposure on 2 nonconsecutive days of the week, for 6 weeks. The MyotonPRO device was used for the assessment of the knee extensor and the ankle dorsiflexors' stiffness and elasticity. Isometric muscle strength was evaluated with a hand-held dynamometer. All measurements were done by the same assessor at baseline, and the following 6 weeks.

RESULTS

Significant group-by-time interactions were found for the elasticity scores of the right (d = 0.84, P = .01) and left (d = 0.77, P = .02) ankle dorsiflexors. Similar to the elasticity measurements, significant group-by-time interactions were observed in the muscle strength scores of the right (d = 0.45, P = .046) and left (d = 1.25, P < .001) ankle dorsiflexors. No significant effects were observed in any of the evaluated muscle stiffness measurements (P > .05), and there was no significant group-by-time interaction in knee-extensor muscle strength and elasticity scores (P > .05).

CONCLUSIONS

The study results indicate that if the ankle dorsiflexor strength and elasticity are desired to be increased, the 6-week WBV exposure in a static squat posture can be used in healthy individuals.

Short-term effects of side-alternating Whole-Body Vibration on cognitive function of young adults

Recent research in rodents and humans revealed that Whole-Body Vibration (WBV) is beneficial for cognitive functions. However, the optimal WBV conditions are not established: contrary to vertical WBV, side-alternating WBV was not investigated before. The present study investigated the short-term effects of side-alternating WBV in standing and sitting posture on specific cognitive function of young adults. We used a balanced cross-over design. Sixty healthy young adults (mean age 21.7 ± 2.0 years, 72% female) participated. They were exposed to three bouts of two-minute side-alternating WBV (frequency 27 Hz) and three control conditions in two different sessions. In one session a sitting posture was used and in the other session a standing (semi-squat) posture. After each condition selective attention and inhibition was measured with the incongruent condition of the Stroop Color-Word Interference Test. WBV significantly (p = 0.026) improved selective attention and inhibition in the sitting posture, but not in the standing posture. The sitting posture was perceived as more comfortable, joyous and less exhaustive as compared to the standing posture. This study demonstrated that side-alternating WBV in sitting posture improves selective attention and inhibition in healthy young adults. This indicates that posture moderates the cognitive effect of WBV, although the effects are still small. Future studies should focus on the working mechanisms and further optimization of settings, especially in individuals who are unable to perform active exercise.

Effect of whole-body vibration on neuromuscular activation and explosive power of lower limb: A systematic review and meta-analysis

OBJECTIVE

The review aimed to investigate the effects of whole-body vibration (WBV) on neuromuscular activation and explosive power.

METHODS

Keywords related to whole-body vibration, neuromuscular activation and explosive power were used to search four databases (PubMed, Web of Science, Google Scholar and EBSCO-MEDLINE) for relevant studies published between January 2000 and August 2021. The methodology of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses was used. The eligibility criteria for the meta-analysis were based on PICOST principles. Methodological assessment used the Cochrane scale. Heterogeneity and publication bias were assessed by I2 index and funnel plots, respectively. The WBV training cycle is a random effect model. Publication bias was also assessed based on funnel plots. This study was registered in PROSPERO (CRD42021279439).

RESULTS

A total of 156 participants data in 18 studies met the criteria and were included in the meta-analysis for quantitative synthesis. Results of the meta-analysis showed significant improvements in lower limb neuromuscular activation immediately after WBV compared with the baseline (SMD = 0.51; 95% CI: 0.26, 0.76; p<0.001), and no significant heterogeneity was observed (I2 = 38%, p = 0.07). In addition, the highest increase in lower limb explosive power was observed (SMD = 0.32; 95% CI: 0.11, 0.52; p = 0.002), and no significant heterogeneity (I2 = 0%, p = 0.80) was noted.

CONCLUSIONS

WBV training could improve neuromuscular activation and explosive power of the lower limb. However, due to different vibration conditions, further research should be conducted to determine standardized protocols targeting performance improvement in athletes and healthy personnel experienced in training.

Effects of whole body vibration exercise combined with weighted vest in older adults: a randomized controlled trial

BACKGROUND

To evaluate the training effects of whole body vibration (WBV) combined with weighted vest (WV) in older adults.

METHODS

This randomized controlled trial study was conducted in healthy older adults living in the community. Fifty-one participants were randomly allocated into 3 groups: group 1 (n = 17), WBV alone, training on WBV at a frequency 30 Hz, amplitude 2 mm, 10 sets of 1 min squats, with 60 s rest, group 2 (n = 15), WV alone, squat exercise, 10 sets of 1 min, with 60 s rest, while WV loaded with 10% body weight and group 3 (n = 19), WBV + WV, combining WBV exercise with the addition of a WV. All groups completed training 3 times per week for 8 weeks. The outcomes were total muscle mass, muscle thickness, maximal isometric strength, single-leg-stance and timed-up-and-go evaluated at baseline and after training.

RESULTS

As a result of training all groups improved their isometric muscle strength with little difference between groups. The single-leg-stance significantly improved only in WBV + WV group 25.1 ± 10.8 s (mean ± 95% CI, p < 0.01). The timed-up-and-go improved in all groups, but the improvement was significantly greater in the WBV + WV group (17.5 ± 6.9%) compared to the WV (8.5 ± 3.2%) and WBV groups (9.2 ± 5.4%, p = 0.043, 0.023 respectively). Rectus femoris muscle thickness and total muscle mass were significantly increased in all groups equally with little difference between groups.

CONCLUSION

The combined WBV + WV had a greater effect on the single-leg-stance and the timed-up-and-go compared to WV or WBV alone.

TRIAL REGISTRATION

TCTR20190306001. Thai Clinical Trials Registry ( www.thaiclinicaltrials.org ). Date of registration: 6 March 2019.

The effect of vibration on kinematics and muscle activation during cycling

Vibration has the potential to compromise performance in cycling. This study aimed to investigate the effects of vibration on full-body kinematics and muscle activation time series. Nineteen male amateur cyclists (mass 74.9 ± 5.9 kg, body height 1.82 ± 0.05 m, Vo2max 57 ± 9 ml/kg/min, age 27 ± 7 years) cycled (216 ± 16 W) with (Vib) and without (NoVib) vibration. Full-body kinematics and muscle activation time series were analysed. Vibration did not affect lower extremity joint kinematics significantly. The pelvic rotated with vibration towards the posterior direction (NoVib: 22.2 ± 4.8°, Vib: 23.1 ± 4.7°, p = 0.016, d = 0.20), upper body lean (NoVib: 157.8 ± 3.0°, Vib: 158.9 ± 3.4°, p = 0.001, d = 0.35) and elbow flexion (NoVib: 27.0 ± 8.2°, Vib: 29.4 ± 9.0°, p = 0.010, d = 0.28) increased significantly with vibration. The activation of lower extremity muscles (soleus, gastrocnemius lat., tibialis ant., vastus med., rectus fem., biceps fem.) increased significantly during varying phases of the crank cycle due to vibration. Vibration increased arm and shoulder muscle (triceps brachii, deltoideus pars scapularis) activation significantly over almost the entire crank cycle. The co-contraction of knee and ankle flexors and extensors (vastus med. - gastrocnemius lat., vastus med. - biceps fem., soleus - tibialis ant.) increased significantly with vibration. In conclusion vibrations influence main tasks such as propulsion and upper body stabilization on the bicycle to a different extent. The effect of vibration on the task of propulsion is limited due to unchanged lower body kinematics and only phase-specific increases of muscular activation during the crank cycle. Additional demands on upper body stabilization are indicated by adjusted upper body kinematics and increased muscle activation of the arm and shoulder muscles during major parts of the cranking cycle.

Effects of Whole-Body Vibration Training with Different Body Positions and Amplitudes on Lower Limb Muscle Activity in Middle-Aged and Older Women

Purpose

The present study was designed to investigate the electromyographic (EMG) response in leg muscles to whole-body vibration while using different body positions and vibration amplitudes.

Methods:

An experimental study with repeated measures design involved a group of community-dwelling middle-aged and older women (n = 15; mean age=60.8 ± 4.18 years). Muscle activity of the gluteus maximus (GM), rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), and gastrocnemius (GS) was measured by surface electromyography, which participants were performing three different body positions during three WBV amplitudes. The body positions included static semi-squat, static semi-squat with elastic band loading, and dynamic semi-squat. Vibration stimuli tested were 0 mm, 2 mm, and 4 mm amplitude and 30 Hz frequencies. And the maximum accelerations produced by vibration stimuli with amplitudes of 2 mm and 4 mm are approximately 1.83 g and 3.17 g.

Results:

Significantly greater muscle activity was recorded in VL, BF, and GS. When WBV was applied to training, compared with the same training without WBV (P < .05). There were significant main effects of body positions on EMGrms for the GM, RF, and VM (P < .05). Compared to static semi-squat, static semi-squat with elastic band significantly increased the EMGrms of GM, and dynamic semi-squat significantly increased the EMGrms of GM, RF and VM (P < .05). And there were significant main effects of amplitudes on EMGrms for the GM, RF, and VM (P < .05). The EMGrms of the VL, BF, and GS at 4 mm were significantly higher than 0 mm, and the EMGrms of the VL and BF at 4 mm were significantly higher than 2 mm. There was no significant body interaction between body positions and amplitudes (P > .05).

Conclusions:

The EMG amplitudes of most leg muscles tested were significantly greater during WBV exposure than in the no-WBV condition. The dynamic semi-squat 4 mm whole-body vibration training is recommended for middle-aged and older women to improve lower limb muscle strength and function.

[Physical activity in cancer - effectiveness of exercise therapy approaches]

The positive effects of oncological exercise therapy are sufficiently proven according to scientific studies. International evidence-based guidelines confirm this importance and recommend physical exercise as part of the standard therapy for cancer. The effects of physical activity on cancer-specific deficits are versatile ranging from positive impact on fatigue syndrome, mortality, incontinence, lymphoedema, CIPN, anxiety, depression to reduction of pain. According to current knowledge, sensorimotor training is recommended for the treatment of polyneuropathy. The actual effectiveness of vibration training in reducing symptom burden is undetermined. There are more than 100 randomized, controlled studies with the highest evidence rating for the management of CrF available. In this regard, exercise therapy is more effective than drug therapy in alleviating the symptomatology of CrF. In addition to the movement-therapeutic approach, a coordinated diet is necessary to avoid nutrition shortages.The evidence on physical activity in oncology must be considered not only in theory, but also in practice and be accepted as a general recommendation for oncology patients. The personalized OTT treatment concept represents a practical implementation and offers a targeted treatment option with low side effects.

Whole-body vibration training for inpatient children and adolescents receiving chemotherapy for first cancer diagnosis: an exploratory feasibility study

Whole-body vibration (WBV) is a feasible and potentially beneficial exercise strategy for managing neuromuscular impairments like decreased strength or flexibility, mobility limitations and bone health in pediatric cancer survivors. However, as starting rehabilitation as early as possible is recommended to preserve physical function, this study investigated the feasibility of WBV for patients receiving cancer treatment for first cancer diagnosis. Eleven patients (various types of cancer, ages 7–17) participated in the supervised WBV intervention concomitant to acute cancer treatment, which involved chemotherapy. Training was implemented as part of a general exercise program and offered 3 days per week during hospitalization (warm-up, four progressive training exercises comprising 60–120 s, 21–27 Hz, 2 mm peak-to-peak-displacement). Feasibility, which was defined as the absence of WBV-related serious adverse events leading to study dropout, was primarily evaluated. Training documentation was additionally analyzed. As a main result, no serious adverse events leading to study dropout were reported. However, two incidents of bleeding (adverse events) were observed in patients with bleeding tendencies and low platelets (thrombocytes < 30,000/μL). After adjusting the platelet count threshold for WBV participation to 30,000/μL, no further incidents occurred. Moreover, due to WBV-related side effects like physical exhaustion, 11% of all training sessions had to be stopped and another 11% required reductions in the vibration load. Patients participated in 48% of the planned sessions. While main reasons for non-attendance were medical issues (35%), only few WBV sessions were missed, not completed or needed modifications due to motivational issues. Consequently, WBV seems to be feasible for inpatient pediatric patients receiving chemotherapy for first cancer diagnosis, given a sufficiently high platelet count of at least 30,000/μL. Although WBV tolerance and training motivation appear high, patient’s reduced medical condition during hospitalization can negatively impact training progression and attendance. Future research is required to confirm our findings on feasibility and to assess efficiency of WBV training for pediatric cancer patients receiving cancer treatment.

Characterisation of the transient mechanical response and the electromyographical activation of lower leg muscles in whole body vibration training

The aim of this study is to characterise the transient mechanical response and the neuromuscular activation of lower limb muscles in subjects undergoing Whole Body Vibration (WBV) at different frequencies while holding two static postures, with focus on muscles involved in shaping postural responses. Twenty-five participants underwent WBV at 15, 20, 25 and 30 Hz while in hack squat or on fore feet. Surface electromyography and soft tissue accelerations were collected from Gastrocnemius Lateralis (GL), Soleus (SOL) and Tibialis Anterior (TA) muscles. Estimated displacement at muscle bellies revealed a pattern never highlighted before that differed across frequencies and postures (p < 0.001). After stimulation starts, muscle oscillation peaks, drops and further stabilises, suggesting the occurrence of a neuromuscular activation to reduce the vibration-induced oscillation. The oscillation attenuation at the SOL muscle correlated with its increased activation (rho = 0.29, p < 0.001). Furthermore, only specific WBV settings led to a significant increase in muscle contraction: WBV-induced activation of SOL and GL was maximal in fore-feet (p < 0.05) and in response to higher frequencies (30 Hz vs 15 Hz, p < 0.001). The analysis of the mechanical dynamics of lower leg muscles highlights a resonant response to WBVs, that for the SOL correlates to the increased muscle activation. Despite differing across frequencies and postures, this resonant behaviour seems to discourage the use of dynamic exercises on vibrating platforms. As for the most efficient WBV combination, calf muscle response to WBVs is maximised if those muscles are already pre-contracted and the stimulation frequencies are in the 25–30 Hz range.

Effect of Whole Body Vibration Conditions on Lower Limb Muscles during Sling Exercise

Exercising in an unstable environment, such as with the use of a sling, improves neuromuscular adaptation by providing effective training stimuli. Moreover, whole body vibration has been used to restore the physical function of patients with nervous system and musculoskeletal disorders. However, there have been few studies on the most appropriate exercise method of combining unstable surface and WBV. The purpose of this study was to investigate the effect of a sling and sonic vibration stimulation on muscle activation while performing a Bulgarian split squat (BSS). Twenty male subjects (age 25.95 ± 2.42 years old, height: 172.59 ± 5.56 cm, weight: 77.74 ± 10.82 kg) participated in the study. The participants randomly performed five types of BS using a sling and sonic vibration (BSS–0 Hz, BSS–4 Hz, BSS–8 Hz, BSS–12 Hz, BSS–20 Hz, and BSS–30 Hz). Each condition was repeated five times. A 60-s break was given for each condition to minimize muscle fatigue. We measured the muscular activities in the gluteus medius, biceps femoris, rectus femoris, vastus medialis, and vastus lateralis. It was observed that muscle activation increased during exercise conditions that provided a sling and sonic vibration in all muscles. In particular, the highest activation appeared in the condition wherein a vibration of 30 Hz was provided. Our results show that the sling exercise combined with a sonic vibration of 30 Hz during the BSS has positive effects on lower limb muscle activity.

EFFECT OF LOWER LIMB EXERCISE ON POSTURE STABILITY AND BRAIN ACTIVITY DURING WHOLE BODY VIBRATION FOR THE ELDERLY

This study aimed to investigate the effect of lower limb exercise on electroencephalogram (EEG) activity and posture stability during whole body vibration (WBV) for healthy elderly people. Subjects were composed of 20 elderly people who were over 60 years old and had no disease. They were subjected to WBV of 30[Formula: see text]Hz and strength intensity of 20 (total 5 sets, 20[Formula: see text]s/set, rest time: 20[Formula: see text]s, except for the final set). The subjects were grouped into two groups. One group of 11 subjects was WBVSt (WBV of upright stance) and the other group of nine subjects was WBVSq (WBV of squat posture). In the WBVSt group, the subjects were requested to maintain a standing position, whereas those in the WBVSq group were asked to perform 60∘-knee flexion squat at 2[Formula: see text]s intervals during WBV stimulation. In this study, the electromyography (EMG) was measured on the right and left erector spinae, rectus femoris, vastus lateralis, vastus medialis, tibialis anterior to evaluate lower limb muscle activity and postural stability during timed up and go (TUG) test before and after WBV. The EEG was measured on frontal (F3, F4, F7, F8), central (Cz, C3, C4), temporal (T3, T4, T5, T6), parietal (P3, P4), and occipital (O1, O2) lobes to evaluate brain activity during the check of mini-mental state examination for dementia screening (MMSE-DS) before and after WBV. The results of this study showed improved postural stability and muscle activation for the healthy elderly during lower limb and WVB exercises. The WBVSq group showed higher changes in TUG-test ([Formula: see text]) and iEMG analysis by EMG ([Formula: see text]) compared with the WBVSt group. However, there was no significant change in MMSE-DS ([Formula: see text]). Because of the increase in relative SMR power by EEG, the central (C4), frontal (F7) and parietal (P3, P4) lobes were activated in WBVSt group ([Formula: see text]); however, all regions, except the parietal lobe, were activated in WBVSq group ([Formula: see text]). Lower limb exercise with WBV stimulation improved postural stability, lower limb muscle, and brain activation for the elderly. These results may be helpful to the protocol of exercise using WBV for the healthy elderly.

The effect of whole body vibration on the sprint ability of Korean national bobsled and skeleton athletes

This study aims to find out whether whole body vibration has an effect on the sprint ability to shorten the time of bobsled-skeleton athletes. Seventeen bobsled-skeleton athletes (male = 11, female = 6) were recruited from Korea Winter Olympics National Team. Participants were randomly assigned to either a sprint immediately after whole body vibration or a sprint without whole body vibration protocol during two separate visits by a period of 3 months. To evaluate the effects of the sprint ability, measurements were performed 60-m sprint recorded test. In males, at the 45m (p<0.05) significant faster sprint section record after WBV more than Non-WBV. In females, at the 15m (p<0.05), 30m (p<0.01), 45m (p<0.05), and 60m (p<0.05) significant faster sprint section record after WBV more than Non-WBV. In males, at the 30m (p<0.05), 45m (p<0.05), and 50m (p<0.05) significant faster sprint cumulative record after WBV more than Non-WBV. In females, at the 15m (p<0.05), 30m (p<0.05), 45m (p<0.01), 50m (p<0.01), and 60m (p<0.01) significant faster sprint cumulative record after WBV more than Non-WBV. This study indicated that significant faster after WBV more than Non-WBV in males and females bobsled-skeleton athletes.

Reporting Guidelines for Whole-Body Vibration Studies in Humans, Animals and Cell Cultures: A Consensus Statement from an International Group of Experts

Simple Summary

Whole-body vibration (WBV) is an exercise or treatment method used in sports, physiotherapy, and rehabilitation. During WBV, people sit, stand, or exercise on a platform that generates vibrations. These vibrations generally occur between 20 and 60 times per second and have a magnitude of one or several millimeters. Research is focused on the effects of WBV on, for instance, physical and cognitive functions as well as the underlying mechanisms that may explain the effects. Research is not only done in humans but in animals and cell cultures as well. It is important to report the studies correctly, completely, and consistently. This way, researchers can interpret and compare each other’s studies, and data of different studies can be combined and analyzed together. To serve this goal, we developed new guidelines on how to report on WBV studies. The guidelines include checklists for human and animal/cell culture research, explanations, and examples of how to report. We included information about devices, vibrations, administration, general protocol, and subjects. The guidelines are WBV-specific and can be used by researchers alongside general guidelines for specific research designs.

Abstract

Whole-body vibration (WBV) is an exercise modality or treatment/prophylaxis method in which subjects (humans, animals, or cells) are exposed to mechanical vibrations through a vibrating platform or device. The vibrations are defined by their direction, frequency, magnitude, duration, and the number of daily bouts. Subjects can be exposed while performing exercises, hold postures, sitting, or lying down. Worldwide, WBV has attracted significant attention, and the number of studies is rising. To interpret, compare, and aggregate studies, the correct, complete, and consistent reporting of WBV-specific data (WBV parameters) is critical. Specific reporting guidelines aid in accomplishing this goal. There was a need to expand existing guidelines because of continuous developments in the field of WBV research, including but not limited to new outcome measures regarding brain function and cognition, modified designs of WBV platforms and attachments (e.g., mounting a chair on a platform), and comparisons of animal and cell culture studies with human studies. Based on Delphi studies among experts and using EQUATOR recommendations, we have developed extended reporting guidelines with checklists for human and animal/cell culture research, including information on devices, vibrations, administration, general protocol, and subjects. In addition, we provide explanations and examples of how to report. These new reporting guidelines are specific to WBV variables and do not target research designs in general. Researchers are encouraged to use the new WBV guidelines in addition to general design-specific guidelines.

sEMG Activity in Superimposed Vibration on Suspended Supine Bridge and Hamstring Curl

Traditionally in strength and conditioning environments, vibration has been transmitted using platforms, barbells, dumbbells, or cables but not suspension devices. This study aimed to examine the effects on the lower limb of applying superimposed vibration on a suspension device. Twenty-one physically active men and women performed supine bridge and hamstring curl exercises in three suspended conditions (non-vibration, vibration at 25 Hz, and vibration at 40 Hz). In each exercise condition, the perceived exertion scale for resistance exercise (OMNI-Res) was registered, and the electromyographic signal was assessed for gastrocnemius (medialis and lateralis), biceps femoris, semitendinosus, gluteus maximus, and rectus femoris. A linear mixed model indicated a significant fixed effect for vibration at 25 Hz and 40 Hz on muscle activity in suspended supine bridge (p < 0.05), but no effect for suspended hamstring curl (p > 0.05). Likewise, the Friedman test showed a significant main effect for vibration at 25 Hz and 40 Hz in suspended supine bridge (p < 0.05) but not for suspended hamstring curl (p > 0.05) on OMNI-Res. Post hoc analysis for suspended supine bridge with vibration at 25 Hz showed a significant activation increase in gastrocnemius lateralis (p = 0.008), gastrocnemius medialis (p = 0.000), semitendinosus (p = 0.003) activity, and for semitendinosus under 40 Hz condition (p = 0.001) compared to the non-vibration condition. Furthermore, OMNI-Res was significantly higher for the suspended supine bridge at 25 Hz (p = 0.003) and 40 Hz (p = 0.000) than for the non-vibration condition. Superimposed vibration at 25 Hz elicits a higher neuromuscular response during the suspended supine bridge, and the increase in vibration frequency also raises the OMNI-Res value.

The Therapeutic Effects of Whole-Body Vibration in Patients With Fibromyalgia. A Randomized Controlled Trial

Fibromyalgia is a chronic pain disease with few effective therapeutic options. We evaluated the efficacy of a 12-weeks therapy program that involves the use of whole body vibration in patients with fibromyalgia. The experimental group (N = 20 patients) participated in a neuromuscular training with a rotational whole body vibration platform for 12 weeks. The control group (N = 20 patients) received no physiotherapy treatment. The following variables were assessed before, after and 3 months after the therapy program: Fibromyalgia impact questionnaire, pain intensity, quality of life, sensitivity measurements (pressure pain thresholds, vibration thresholds), motor function tasks (Berg scale, 6-min walk test, isometric back muscle strength), and static and dynamic balance. We found improvements in the indexes of functional disability, static equilibrium and vibration sensitivity and a reduction of pain sensitivity. Our results showed that the intervention group improved almost all parameters immediately after the therapy program, in contrast to the control group that showed no changes. These improvements were not maintained in the follow-up. The whole body vibration therapy can be an effective therapy in patients with fibromyalgia and it can improve symptomatology and quality of life in these patients.

Feasibility of a combined supervised and home-based whole-body vibration intervention in children after inpatient oncological treatment

Purpose

Reduced physical performance due to therapy-related dysfunctions in children diagnosed with cancer contributes to insufficient physical activity levels. It is therefore essential that relevant functions are restored. Whole-body vibration (WBV) training, a neuromuscular stimulating exercise intervention, could have the potential to target those functions adequately. Therefore, the aim of this study was to evaluate the feasibility of a combined supervised and home-based WBV intervention with children after inpatient oncological treatment.

Methods

Eight children aged 6–21 years were included after cessation of their inpatient oncological treatment. They performed a 12-week WBV training including one supervised and two home-based sessions per week according to a standardized training protocol. Feasibility, adherence and compliance to the vibration protocol were documented. Subjective benefits and satisfaction were assessed using a questionnaire.

Results

Study participants attended 84.03 ± 13.09% of WBV sessions. No serious adverse events occurred. Some patients reported side effects partially resulting in modifications of the vibration protocol by therapists. Almost all children regarded the intervention as beneficial.

Conclusion

A combined supervised and home-based WBV intervention with children after inpatient oncological treatment is feasible and safe. The beneficial potential regarding relevant sensory and motor dysfunctions is now to be investigated.

Trial registration number and date of registration

DRKS00014713 15.05.2018

The Effect of Cycling-specific Vibration on Neuromuscular Performance

PURPOSE

This study aimed to provide an understanding of how surface-induced vibrations in cycling interfere with short-term neuromuscular performance.

METHODS

The study was conducted as a cross-sectional single cohort trial. Thirty trained cyclists participated (mass = 75.9 ± 8.9 kg, body height = 1.82 ± 0.05 m, V˙O2max = 63 ± 6.8 mL·kg-1⋅min-1). The experimental intervention included a systematic variation of the two independent variables: vibration (Vib: front dropout, 44 Hz, 4.1 mm; rear dropout, 38Hz, 3.5 mm; NoVib) and cranking power (LOW, 137 ± 14 W; MED, 221 ± 18 W; HIGH, 331 ± 65 W) from individual low to submaximal intensity. Dependent variables were transmitted accelerations to the body, muscular activation (gastrocnemius medialis, gastrocnemius lateralis, soleus, vastus lateralis, vastus medialis, rectus femoris, triceps brachii, flexor carpi ulnaris, and lumbar erector spinae), heart rate, and oxygen consumption.

RESULTS

The main findings show that the root-mean-square of local accelerations increased with vibration at the lower extremities, the torso, and the arms-shoulder system. The activation of gastrocnemius medialis, gastrocnemius lateralis, soleus, triceps brachii, and flexor carpi ulnaris increased significantly with vibration. The activation of vastus lateralis increased significantly with vibration only at HIGH cranking power. Oxygen consumption (+2.7%) and heart rate (+5%-7%) increased significantly in the presence of vibration.

CONCLUSIONS

Vibration is a full-body phenomenon. However, the impact of vibration on propulsion is limited as the main propulsive muscles at the thigh are not majorly affected. The demands on the cardiopulmonary and respiratory system increased slightly in the presence of vibration.

Effects of Whole-Body Vibration Therapy on Quadriceps Function in Patients With Anterior Cruciate Ligament Reconstruction: A Systematic Review

CONTEXT

Quadriceps dysfunction is common for patients after anterior cruciate ligament reconstruction (ACLR). Whole-body vibration (WBV) could effectively treat quadriceps dysfunction.

OBJECTIVE

To summarize WBV protocols for patients with ACLR and to evaluate the effects of WBV on quadriceps function.

DATA SOURCES

PubMed, CINAHL, SportDiscus, Web of Science, Medline, and Embase were searched from inception to January 2020.

STUDY SELECTION

Randomized controlled trials recruiting patients with ACLR, using WBV as intervention, and reporting at least 1 of the following outcomes, strength, rate of torque development (RTD), and voluntary activation ratio of quadriceps, were included.

STUDY DESIGN

Systematic review.

EVIDENCE LEVEL

Level 3.

METHODS

This systematic review was reported according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Quality of evidence was determined by PEDro criteria and GRADE system. Participant characteristics, interventions, and the relevant results of the included studies were extracted and synthesized in a narrative way.

RESULTS

In total, 8 studies were included. Of these, 2 studies had serious risk of bias. Five of 8 studies implemented a series of WBV program ranging from 2 to 10 weeks in duration, while the other 3 studies implemented a single session of WBV. Eight WBV protocols were reported. The reported outcomes consisted of quadriceps strength, RTD, and central activation ratio. WBV protocols were heterogeneous. Low quality of evidence supported that exclusive conventional rehabilitation was more effective than exclusive WBV therapy in increasing quadriceps strength. Low quality of evidence supported that WBV combined with conventional rehabilitation was more beneficial in increasing quadriceps strength when compared with conventional rehabilitation alone. Very low quality of evidence supported the efficacy of a single session of WBV on quadriceps function.

CONCLUSIONS

There is no standardized WBV protocol for patients with ACLR, and the effectiveness of WBV in rehabilitation on quadriceps function remains inconclusive.

Effect of Whole-Body Vibration Training on Muscle Activation for Individuals with Knee Osteoarthritis

Whole-body vibration (WBV) training may improve the strength of lower extremity muscles in patients with knee osteoarthritis (KOA), but the inconsistency in vibration parameters leads to differences in findings. This cross-sectional study is aimed at observing the effects of different vibration frequencies and knee flexion angles on the activation of lower extremity muscles in patients with KOA. Enrolled participants received WBV training at 0, 30, and 60° knee flexion angles with vibration frequencies of 0, 5, 10, and 20 Hz. Activation rates for vastus medialis, vastus lateralis, rectus femoris, biceps femoris, and semitendinosus in different combinations were collected through surface electromyography. The effects of frequency and angle on muscle activation rate were quantified by repeated measures ANOVA. Individual and synergistic effects of frequency and angle were also analysed. Twenty-six participants with KOA were included. Muscle activation increased with the vibration frequency in 0–20 Hz range and with knee flexion angle in 0–60° range. WBV training at 20 Hz was the most effective for knee muscle activation, and static squatting at 60° was the most suitable for WBV training. Therefore, WBV training can increase the activation rate of knee flexor and extensor muscles in patients with KOA, and the most efficient combination was 20 Hz vibration frequency and 60° knee flexion. When applying WBV to patients with KOA, individual differences and rehabilitation purposes should be considered in selecting vibration parameters and knee angle to effectively increase neuromuscular activity.

A Comparison of the Effect of Two Types of Whole Body Vibration Platforms on Fibromyalgia. A Randomized Controlled Trial

Whole body vibration has been proven to improve the health status of patients with fibromyalgia, providing an activation of the neuromuscular spindles, which are responsible for muscle contraction. The present study aimed to compare the effectiveness of two types of whole body vibrating platforms (vertical and rotational) during a 12-week training program. Sixty fibromyalgia patients (90% were women) were randomly assigned to one of the following groups: group A (n = 20), who performed the vibration training with a vertical platform; group B (n = 20), who did rotational platform training; or a control group C (n = 20), who did not do any training. Sensitivity measures (pressure pain and vibration thresholds), quality of life (Quality of Life Index), motor function tasks (Berg Scale, six-minute walking test, isometric back muscle strength), and static and dynamic balance (Romberg test and gait analysis) were assessed before, immediately after, and three months after the therapy program. Although both types of vibration appeared to have beneficial effects with respect to the control group, the training was more effective with the rotational than with vertical platform in some parameters, such as vibration thresholds (p < 0.001), motor function tasks (p < 0.001), mediolateral sway (p < 0.001), and gait speed (p < 0.05). Nevertheless, improvements disappeared in the follow-up in both types of vibration. Our study points out greater benefits with the use of rotational rather than vertical whole body vibration. The use of the rotational modality is recommended in the standard therapy program for patients with fibromyalgia. Due to the fact that the positive effects of both types of vibration disappeared during the follow-up, continuous or intermittent use is recommended.

A comparison between whole-body vibration and conventional training on pain and performance in athletes with patellofemoral pain

INTRODUCTION

Patellofemoral pain (PFP) is the most common cause of anterior knee pain in athletes, which affects their performance especially during single leg activities. The aim of this study was to compare the effects of whole-body vibration training (WBVT) and conventional training (CT) on pain and performance in athletes with PFP.

METHODS

30 athletes with unilateral PFP were randomly assigned to the WBVT (6 women, 9 men) or CT (7 women, 8 men) group. All participants received training for 4 weeks in 12 sessions. The outcomes of pain and performance were measured at three points in time: baseline, immediately after training and 2 weeks after training. Pain was assessed with the Numeric Pain Rating Scale (NPRS). Performance was measured with the leg-press test and the Kujala Patellofemoral Score (KPS).

RESULTS

In both groups, pain intensity decreased significantly (p < 0.001) and the KPS and number of leg presses increased significantly (p < 0.001) with time. There was no significant difference between groups for changes in the pain score (p = 0.896), KPS (p = 0.463) or leg press (p = 0.796) results.

CONCLUSION

Whole-body vibration training had the same effect as exercise therapy on pain reduction and on improvements in performance in athletes with PFP.

Managing Vibration Training Safety by Using Knee Flexion Angle and Rating Perceived Exertion

Whole-body vibration (WBV) is commonly applied in exercise and rehabilitation and its safety issues have been a major concern. Vibration measured using accelerometers can be used to further analyze the vibration transmissibility. Optimal bending angles and rating of perceived exertion (RPE) evaluations have not been sufficiently explored to mitigate the adverse effect. Therefore, the aims of this study were to investigate the effect of various knee flexion angles on the transmissibility to the head and knee, the RPE during WBV exposure, and the link between the transmissibility to the head and the RPE. Sixteen participants randomly performed static squats with knee flexion angles of 90, 110, 130, and 150 degrees on a WBV platform. Three accelerometers were fixed on the head, knee, and center of the vibration platform to provide data of platform-to-head and platform-to-knee transmissibilities. The results showed that the flexion angle of 110 degrees induced the lowest platform-to-head transmissibility and the lowest RPE (p < 0.01). A positive correlation between RPE and the platform-to-head transmissibility was observed. This study concluded that a knee flexion of about 110 degrees is most appropriate for reducing vibration transmissibility. The reported RPE could be used to reflect the vibration impact to the head.

Effects of different vibration frequencies on muscle strength, bone turnover and walking endurance in chronic stroke

This randomized controlled trial aimed to evaluate the effects of different whole body vibration (WBV) frequencies on concentric and eccentric leg muscle strength, bone turnover and walking endurance after stroke. The study involved eighty-four individuals with chronic stroke (mean age = 59.7 years, SD = 6.5) with mild to moderate motor impairment (Fugl-Meyer Assessment lower limb motor score: mean = 24.0, SD = 3.5) randomly assigned to either a 20 Hz or 30 Hz WBV intervention program. Both programs involved 3 training sessions per week for 8 weeks. Isokinetic knee concentric and eccentric extension strength, serum level of cross-linked N-telopeptides of type I collagen (NTx), and walking endurance (6-min walk test; 6MWT) were assessed at baseline and post-intervention. An intention-to-treat analysis revealed a significant time effect for all muscle strength outcomes and NTx, but not for 6MWT. The time-by-group interaction was only significant for the paretic eccentric knee extensor work, with a medium effect size (0.44; 95% CI: 0.01, 0.87). Both WBV protocols were effective in improving leg muscle strength and reducing bone resorption. Comparatively greater improvement in paretic eccentric leg strength was observed for the 30 Hz protocol.

Acute effect of whole-body vibration on acceleration transmission and jumping performance in children

BACKGROUND

Whole-body vibration (WBV) has emerged as a potential intervention paradigm for improving motor function and bone growth in children with disabilities. However, most evidence comes from adult studies. It is critical to understand the mechanisms of children with and without disabilities responding to different WBV conditions. This study aimed to systematically investigate the acute biomechanical and neuromuscular response in typically developing children aged 6-11 years to varying WBV frequencies and amplitudes.

METHODS

Seventeen subjects participated in this study (mean age 8.7 years, 10 M/7F). A total of six side-alternating WBV conditions combining three frequencies (20, 25, and 30 Hz) and two amplitudes (1 and 2 mm) were randomly presented for one minute. We estimated transmission of vertical acceleration across body segments during WBV as the average rectified acceleration of motion capture markers, as well as lower-body muscle activation using electromyography. Following WBV, subjects performed countermovement jumps to assess neuromuscular facilitation.

FINDINGS

Vertical acceleration decreased from the ankle to the head across all conditions, with the greatest damping occurring from the ankle to the knee. Acceleration transmission was lower at the high amplitude than at the low amplitude across body segments, and the knee decreased acceleration transmission with increasing frequency. In addition, muscle activation generally increased with frequency during WBV. There were no changes in jump height or muscle activation following WBV.

INTERPRETATION

WBV is most likely a safe intervention paradigm for typically developing children. Appropriate WBV intervention design for children with and without disabilities should consider WBV frequency and amplitude.

Effects of whole body vibration exercise on lumbar-abdominal muscles activation for patients with chronic low back pain

Background

Whole body vibration (WBV) training as an intervention method can cure chronic low back pain (CLBP). Different WBV parameters exert different effects on lumbar-abdominal muscle performance. Currently, there is a lack of study researched the influence of WBV training on patients with CLBP by lumbar–abdominal muscle activity. Therefore, this study aimed to investigate how WBV and exercise and their interactions influence lumbar-abdominal muscle activity in patients with CLBP.

Methods

a group of ambulatory patients with chronic low back pain. Muscle activities of the multifidus (MF), erector spinae (ES), abdominal oblique externus muscle (AOE) and the rectus abdominis muscle (RA) were measured by surface electromyography, whereas participants performed 4 different exercises (single bridge, plank, side stay and V crunch) during three whole body vibration conditions and a no-vibration condition in a single experimental session.

Results

Compared with the same exercises without whole body vibration, muscle activity increased when whole body vibration was added to the exercises. MF; the WBV frequency (P = 0.002,) and exercise (P < 0.001) presented significant effects on the root mean square of MF, whereas exercise * frequency (P = 0.044) also resulted in significant interaction effects. ES: the significant differences were detected at WBV frequency (P < 0.001), exercise (P < 0.001), the interaction effect of exercise and frequency (P = 0.225) was no significant. RA: the significant difference was detected at WBV frequency (P = 0.018), the effect of exercise (P = 0.590) and the exercise * frequency interaction (P = 0.572) were no significant. AOE: the significant difference was detected at WBV frequency (P < 0.001), the effect of exercise (P = 0.152) and the exercise * frequency interaction (P = 0.380) were no significant.

Conclusion

Adding whole body vibration to exercise could increase muscle activation of lumbar–abdominal muscle in patients with CLBP. The optimum frequency for lumbar–abdominal muscles is 15 Hz. The best exercises include plank for multifidus and erector spinae, V crunch for rectus abdominis and single bridge for abdominal oblique externus.

Clinical registration

Trial registration: ChiCTR-TRC-13003708. Registered 19 October 2013.

The code of ethical approval

2014008.

Effect of Long-Term Repeated Interval Rehabilitation on the Gross Motor Function Measure in Children with Cerebral Palsy

BACKGROUND

The efficacy of interventions for cerebral palsy (CP) has been frequently investigated with inconclusive results and motor function measured by the Gross Motor Function Measure (GMFM-66) is common.

OBJECTIVE

In this observational analysis, we quantify the GMFM-66 change scores of the second and third year of a multimodal rehabilitation program (interval rehabilitation including home-based, vibration-assisted training) in children with CP.

METHODS

The study was a retrospective analysis of children with CP (2-13 years) participating for a second (n = 262) and third year (n = 86) in the rehabilitation program with GMFM-66 scores at start (M0), after 4 months (M4) of intensive training, and after 8 months of follow-up (M12). A method was previously developed to differentiate between possible treatment effects and expected development under standard of care for GMFM-66 scores using Cohen's d effect size (ES; size of difference).

RESULTS

After the treatment phase of 4 months (M4) in the second year, 125 of 262 children were responder (ES ≥ 0.2) and 137 children nonresponder (ES < 0.2); mean ES for nonresponder was -0.212 (trivial) and for responder 0.836 (large). After M4 in the third year, 43 children of 86 were responder (ES = 0.881 [large]) and 43 nonresponder (ES = -0.124 [trivial]).

DISCUSSION AND CONCLUSION

Repeated rehabilitation shows a large additional treatment effect to standard of care in 50% of children which is likely due to the intervention, because in the follow-up period (standard of care), no additional treatment effect was observed and the children followed their expected development.

Effects of whole-body vibrations on neuromuscular fatigue: a study with sets of different durations

BACKGROUND

Whole body vibrations have been used as an exercise modality or as a tool to study neuromuscular integration. There is increasing evidence that longer WBV exposures (up to 10 minutes) induce an acute impairment in neuromuscular function. However, the magnitude and origin of WBV induced fatigue is poorly understood.

PURPOSE

The study aimed to investigate the magnitude and origin of neuromuscular fatigue induced by half-squat long-exposure whole-body vibration intervention (WBV) with sets of different duration and compare it to non-vibration (SHAM) conditions.

METHODS

Ten young, recreationally trained adults participated in six fatiguing trials, each consisting of maintaining a squatting position for several sets of the duration of 30, 60 or 180 seconds. The static squatting was superimposed with vibrations (WBV30, WBV60, WBV180) or without vibrations (SHAM30, SHAM60, SHAM180) for a total exercise exposure of 9-minutes in each trial. Maximum voluntary contraction (MVC), level of voluntary activation (%VA), low- (T20) and high-frequency (T100) doublets, low-to-high-frequency fatigue ratio (T20/100) and single twitch peak torque (TWPT) were assessed before, immediately after, then 15 and 30 minutes after each fatiguing protocol.

RESULT

Inferential statistics using RM ANOVA and post hoc tests revealed statistically significant declines from baseline values in MVC, T20, T100, T20/100 and TWPT in all trials, but not in %VA. No significant differences were found between WBV and SHAM conditions.

CONCLUSION

Our findings suggest that the origin of fatigue induced by WBV is not significantly different compared to control conditions without vibrations. The lack of significant differences in %VA and the significant decline in other assessed parameters suggest that fatiguing protocols used in this study induced peripheral fatigue of a similar magnitude in all trials.

The immediate effect of whole-body vibration on rectus abdominis muscle activity and cutaneous temperature: A randomized controlled trial

OBJECTIVES

To compare acute effects of isometric abdominal exercises performed with or without vibration on the electromyographic activity and cutaneous temperature in the abdominal region of physically active individuals.

METHODS

A randomized controlled crossover clinical trial was undertaken in thirty volunteers who completed one unique session of two different protocols of interventions apart from a week from each other, in a two-week study protocol. The subjects were randomly divided in to two groups of 15 volunteers; both were assigned to perform board exercise (30 s on the front, right and left lateral boards, with a rest interval of 2 min). The first group performed it on a vibrating platform at a frequency of 30 Hz for the first week, while the remaining participants executed the same exercise without stimulates vibration. In the second week the protocol was inverted. The outcome were surface electromyography (EMG) data for the rectus abdominis muscle (RAM) and cutaneous temperature (CT) of the abdominal region. Normality was accepted, and Student's t-tests were used to compare the measurements for dependents variables (P < 0.05).

RESULTS

There were no differences in RAM activation and CT between protocols with or without vibration (P > 0.05). CT increased (P = 0.001) after both the exercises with and without vibration.

CONCLUSION

The results suggest that there were no effects in cutaneous temperature or muscle activation through the use of vibration associated with isometric abdominal exercises.

Effects of whole-body vibration on muscle strength, quadriceps muscle thickness and functional capacity in kidney transplant recipients: A randomized controlled trial

BACKGROUND

Whole-body vibration (WBV) may be an alternative of physical training for kidney transplant recipients.

OBJECTIVE

To evaluate the effect of a training program on quadriceps muscle strength and thickness, distance walked in the 6-min walking test (6MWT), respiratory muscle strength and quality of life in adult kidney transplant recipients.

DESIGN

Randomized controlled clinical trial.

METHOD

Twelve kidney transplant recipients of both genders who underwent WBV training (35 Hz) twice a week for 12 weeks on alternate days (WBVG), and training with a Sham Group (SG) were evaluated before and after intervention.

RESULTS

No difference was observed in quadriceps muscle strength and thickness between groups, however a large (d = 0.81) and a small (d = 0.44) effect size were observed after the training, respectively. Both groups improved the execution time of Sit-to-Stand Test before and after analysis, but this effect did not show superiority between them, however there was a large effect size provided by training (d = 1.11). No changes were observed between groups in relation to inspiratory muscle strength, but training effects could be observed by the effect size after the study period (d = 0.59). No changes were observed regarding the distance walked in the 6MWT and the effect size was small (d = 0.31).

CONCLUSION

WBV program would induce physiological responses that must be taken into consideration in adults' kidney transplant recipients. Our results show considerable effect sizes were observed for muscle strength and quadriceps thickness, inspiratory muscle strength, and 6MWT walking distance, although no difference was observed between groups at the end of the study.

The effect of road-bike damping on neuromuscular short-term performance

The aim of this study was to understand if and how surface-induced vibrations and road bike damping affect short-term neuromuscular performance in cycling. Thirty cyclists (mass 75.9 ± 8.9 kg, height 1.82 ± 0.05 m, Vo2max 63.0 ± 6.8 ml/min/kg) performed steady-state and maximum effort tests with and without vibration exposure (front dropout: 44 Hz, 4.1 mm; rear dropout: 38 Hz, 3.5 mm) on a damped and a nondamped bike. Transmitted accelerations to the musculoskeletal system, activation of lower extremity muscles (gast. med., soleus, vast. med., rec. fem.) and upper body muscles (erec. spinae, deltoideus, tric. brachii), oxygen uptake, heart rate and crank power output were measured. The main findings indicate a transmission of vibration to the whole body, but since no major propulsive muscles increase their activation with vibration, the systemic energy demand increases only marginally with vibration. Damping reduces vibrations at the upper body, which indicates an increase in comfort, but has no effect on the vibration transfer to the lower extremities. Therefore, road bike damping does not affect neuromuscular response of the propulsive muscle groups and energy demand. Consequently, short-term power output does not increase with damping.

Effects of Whole-Body Vibration Training and Blood Flow Restriction on Muscle Adaptations in Women: A Randomized Controlled Trial

Centner, C, Ritzmann, R, Gollhofer, A, and König, D. Effects of whole-body vibration training and blood flow restriction on muscle adaptations in women: a randomized controlled trial. J Strength Cond Res 34(3): 603-608, 2020-The purpose of the present randomized controlled trial was to investigate potential synergistic effects of whole-body vibration (WBV) training combined with blood flow restriction (BFR) on muscle mass and strength, and jump performance. Fifty healthy women (26.1 ± 4.6 years) were randomly allocated to one of the following experimental groups: WBV training combined with BFR (WBV + BFR) or WBV only. Before and after the 10-week training intervention, muscle cross-sectional area (CSA) of the vastus lateralis (VL) and gastrocnemius medialis (GM) was evaluated. Additionally, changes in muscle strength and jump performance were assessed before and after the intervention. The level of significance was set to p < 0.05. Vastus lateralis muscle CSA increased in both groups (p < 0.05). The increase in CSA was less pronounced after WBV than WBV + BFR, although the difference was not significant (p = 0.30). Likewise, GM CSA demonstrated comparable increases in both groups with a significant main effect of time (p < 0.05) but no interaction effect (p = 0.89). Assessment of muscular strength (p = 0.70) and jump performance (p = 0.40) did not reveal significant differences between the groups. The results of the present study indicate that the combination of WBV training with BFR shows a noticeable trend toward higher increases in muscle CSA compared with WBV alone. Despite the lack of significance, the results imply clinical relevance particularly in populations showing contraindications toward high training loads. This, however, needs to be confirmed in future research.

Whole-Body Vibration for Individuals with Reconstructed Anterior Cruciate Ligament: A Systematic Review

Background

ACL ruptures are a prevalent condition, affecting daily living activities, associated with high financial burden.

Objective

To assess the effect of whole-body vibration (WBV) in the rehabilitation of patients with reconstructed anterior cruciate ligament. Methodology. An electronic search in Pubmed, Scopus, Web of Science, and PEDro databases was conducted and randomized controlled trials (RCTs) in humans that analysed the effects of WBV in patients with ACL injury subjected to reconstruction surgery, published in English, Portuguese, Spanish, Italian, or French were included. Records were identified through database search and reference screening by two reviewers, which independently examined titles and abstracts and irrelevant studies were excluded based in eligibility criteria. Relevant full texts were analysed for eligibility, and all relevant studies were included in the systematic review.

Results

Ten studies were included in the systematic review with a mean methodological quality score of 6. Results demonstrate positive effects of WBV in relevant outcomes such as knee function, electromyographic activity, balance, and muscle strength.

Conclusions

WBV demonstrated a positive effect in strength, balance, electromyographic activity, and knee function.

Potential Application of Whole Body Vibration Exercise For Improving The Clinical Conditions of COVID-19 Infected Individuals: A Narrative Review From the World Association of Vibration Exercise Experts (WAVex) Panel

COVID-19 is a highly infectious respiratory disease which leads to several clinical conditions related to the dysfunction of the respiratory system along with other physical and psychological complaints. Severely affected patients are referred to intensive care units (ICUs), limiting their possibilities for physical exercise. Whole body vibration (WBV) exercise is a non-invasive, physical therapy, that has been suggested as part of the procedures involved with pulmonary rehabilitation, even in ICU settings. Therefore, in the current review, the World Association of Vibration Exercise Experts (WAVEX) reviewed the potential of WBV exercise as a useful and safe intervention for the management of infected individuals with COVID-19 by mitigating the inactivity-related declines in physical condition and reducing the time in ICU. Recommendations regarding the reduction of fatigue and the risk of dyspnea, the improvement of the inflammatory and redox status favoring cellular homeostasis and the overall improvement in the quality of life are provided. Finally, practical applications for the use of this paradigm leading to a better prognosis in bed bound and ICU-bound subjects is proposed.

Urinary Incontinence in Women: Modern Methods of Physiotherapy as a Support for Surgical Treatment or Independent Therapy

Urinary incontinence (UI) is a common health problem affecting quality of life of nearly 420 million people, both women and men. Pelvic floor muscle (PFM) training and other physiotherapy techniques play an important role in non-surgical UI treatment, but their therapeutic effectiveness is limited to slight or moderate severity of UI. Higher UI severity requires surgical procedures with pre- and post-operative physiotherapy. Given that nearly 30%-40% of women without dysfunction and about 70% with pelvic floor dysfunction are unable to perform a correct PFM contraction, therefore, it is particularly important to implement physiotherapeutic techniques aimed at early activation of PFM. Presently, UI physiotherapy focuses primarily on PFM therapy and its proper cooperation with synergistic muscles, the respiratory diaphragm, and correction of improper everyday habits for better pelvic organ support and continence. The purpose of this work is a systematic review showing the possibilities of using physiotherapeutic techniques in the treatment of UI in women with attention to the techniques of PFM activation. Evidence of the effectiveness of well-known (e.g., PFM training, biofeedback, and electrostimulation) and less-known (e.g., magnetostimulation, vibration training) techniques will be presented here regarding the treatment of symptoms of urinary incontinence in women.

Whole-body vibration modulates leg muscle reflex and blood perfusion among people with chronic stroke: a randomized controlled crossover trial

This study aimed to investigate the acute effect of whole-body vibration (WBV) on the reflex and non-reflex components of spastic hypertonia and intramuscular blood perfusion among individuals with chronic stroke. Thirty-six people with chronic stroke (age: 61.4 ± 6.9 years) participated in this randomized controlled cross-over study. Each participant underwent two testing conditions: static standing for 5 minutes with WBV (30 Hz, 1.5 mm) or no-vibration. We assessed the soleus H-reflex, shear modulus (ultrasound elastography) and vascular index (color power Doppler ultrasound) of the medial gastrocnemius (MG) muscle on either paretic or non-paretic side at baseline and every 1-min post-intervention up to 5 minutes. The results revealed a significant inhibition of the H/M ratio bilaterally for the WBV condition (absolute change on paretic side: 0.61 ± 0.35, p = 0.001; non-paretic side: 0.34 ± 0.23, p = 0.001), but not the control condition. The inhibition of H-reflex was sustained up to 4 minutes and 3 minutes on the paretic and non-paretic side, respectively. The vascular index of MG muscle was significantly increased only for the WBV condition [paretic: from 0.55 ± 0.07 to 1.08 ± 0.18 (p = 0.001); non-paretic: from 0.82 ± 0.09 to 1.01 ± 0.13 (p < 0.001)], which lasted for 3 minutes and 5 minutes, respectively. No significant change of the shear modulus in the MG muscle was observed, regardless of the testing condition. Based on our results, WBV had an acute effect on modulating spastic hypertonia dominated by hyperreflexia in people with chronic stroke and facilitating greater intramuscular blood perfusion. No acute effect on passive muscle stiffness was observed.

Acute Effects of Whole-Body Vibration on the Postural Organization of Gait Initiation in Young Adults and Elderly: A Randomized Sham Intervention Study

Whole-body vibration (WBV) is a training method that exposes the entire body to mechanical oscillations while standing erect or seated on a vibrating platform. This method is nowadays commonly used by clinicians to improve specific motor outcomes in various sub-populations such as elderly and young healthy adults, either sedentary or well-trained. The present study investigated the effects of acute WBV application on the balance control mechanisms during gait initiation (GI) in young healthy adults and elderly. It was hypothesized that the balance control mechanisms at play during gait initiation may compensate each other in case one or several components are perturbed following acute WBV application, so that postural stability and/or motor performance can be maintained or even improved. It is further hypothesized that this capacity of adaptation is altered with aging. Main results showed that the effects of acute WBV application on the GI postural organization depended on the age of participants. Specifically, a positive effect was observed on dynamic stability in the young adults, while no effect was observed in the elderly. An increased stance leg stiffness was also observed in the young adults only. The positive effect of WBV on dynamic stability was ascribed to an increase in the mediolateral amplitude of "anticipatory postural adjustments" following WBV application, which did overcompensate the potentially destabilizing effect of the increased stance leg stiffness. In elderly, no such anticipatory (nor corrective) postural adaptation was required since acute WBV application did not elicit any change in the stance leg stiffness. These results suggest that WBV application may be effective in improving dynamic stability but at the condition that participants are able to develop adaptive changes in balance control mechanisms, as did the young adults. Globally, these findings are thus in agreement with the hypothesis that balance control mechanisms are interdependent within the postural system, i.e., they may compensate each other in case one component (here the leg stiffness) is perturbed.

The immediate influence of various whole-body vibration frequency on balance and walking ability in children with cerebral palsy: a pilot study

The purpose of this pilot study is to examine the immediate effect of interventions based on the frequency of whole-body vibration on children with cerebral palsy’s balance and walking abilities. A total of 12 were selected as subjects. All subjects measured 10-m walking test (10MWT), Timed Up and Go (TUG) test and measured sway length (SL) and limit of stability (LOS) by bio-rescue. And those were performed again after the frequencies of the 12, 18, and 26 Hz were applied respectively. To check the immediate effect, all subjects performed only one frequency of interventions per day and no other treatment was performed in parallel to control the foreign variables. After intervention, 10MWT were significantly increased in the 12 and 18 Hz groups (P<0.05). TUG test and LOS were significantly increased in the 18 Hz group (P<0.05). There were no significant differences on TUG, SL, and LOS in the 12 Hz group. There were no significant differences on 10MWT, TUG, SL, and LOS in the 26 Hz group. Looking at the results of this study, the immediate effect of whole-body vibration shows that the frequency of the 18 Hz group is the most effective interventions in promoting walking and balancing abilities in children with cerebral palsy than frequencies of the 12 and 26 Hz groups.

The effects of patellar tendon vibration on quadriceps strength in anterior cruciate ligament reconstructed knees

OBJECTIVES

To examine the immediate effects of prolonged patellar tendon vibration on quadriceps strength in anterior cruciate ligament reconstructed (ACLR) knees with bone-patellar tendon-bone (BTB) grafts and non-BTB grafts, and healthy control knees.

DESIGN

Pretest-posttest design.

SETTING

Laboratory.

PARTICIPANTS

Young adult participants were stratified into one of three groups: non-BTB graft (n = 25), BTB graft (n = 26), and controls without ACLR (n = 21).

MAIN OUTCOME MEASURES

Maximum voluntary isometric contraction (MVIC) knee extension torque was measured at baseline and following a 20-min vibration intervention applied locally to the patellar tendon.

RESULTS

Our findings suggest there was no difference in the effects of vibration on knee extension torque between the three groups. Knee extension torque significantly increased (effect size = 0.52 [0.18 to 0.81]) from baseline to post-vibration across all three groups (0.30 ± 0.26 Nm/kg, 21.8 ± 20.0%). Both ACLR groups demonstrated significantly lower knee extension torque compared the control group.

CONCLUSIONS

The vibration intervention had a net excitatory effect on quadriceps strength in all three groups and there were no differences in the magnitude of change between the three groups. Vibration could become a useful tool for enhancing quadriceps strength in ACLR and healthy knees.

Muscle activity of Bulgarian squat. Effects of additional vibration, suspension and unstable surface

Practitioners of strength and conditioning are increasingly using vibration and unstable environments to enhance training effects. However, little evidence has been found comparing the use of suspension devices and vibratory platforms used in the Bulgarian squat. The purpose of this cross-sectional study was to examine the effect of suspension devices (TRX®), unstable surfaces (BOSU®), and vibration plates on muscle activity and force during the Bulgarian squat. Twenty physically active male students (age = 24.40 ± 3.63 years) performed a set of five repetitions of Bulgarian squats, suspended lunges, suspended lunges-BOSU, suspended lunges-Vibro30, and suspended lunges-Vibro40 (vibration 30 Hz or 40 Hz and 4 mm of amplitude). A randomized within-subject design was used to compare leg muscle activity, vertical ground reaction forces, and force exerted on the strap across the five exercises. Results showed no significant differences in muscle activity between the Bulgarian squat and suspended lunge (p = 0.109, d = 2.84). However, the suspended lunge significantly decreased muscle activation compared to the suspended lunge-BOSU (p = 0.012, d = 0.47), suspended lunge-Vibro30 (p = 0.001, d = 1.26), and suspended lunge-Vibro40 (p = 0.000, d = 1.51). Likewise, the Bulgarian squat achieved lower activity than the suspended lunge-Vibro40 (p = 0.010, d = 0.96). The force on the strap significantly decreased in the suspended lunge-BOSU compared to the suspended lunge-Vibro30 (p = 0.009, d = 0.56). The suspended lunge achieved higher front leg force production than the Bulgarian squat (p = 0.006, d = 0.48). In conclusion, leaning the rear leg on a suspension device does not provoke an increase in the activation of the front leg during the Bulgarian squat but increases the vertical ground reaction forces. Thus, the use of unstable surfaces or vibration plates for the front leg increased muscular activity when performing a suspended lunge.