scholarly journals Effects of different vibration frequencies, amplitudes and contraction levels on lower limb muscles during graded isometric contractions superimposed on whole body vibration stimulation

2019 ◽  
Vol 6 ◽  
pp. 205566831982746 ◽  
Author(s):  
Amit N Pujari ◽  
Richard D Neilson ◽  
Marco Cardinale

Background Indirect vibration stimulation, i.e., whole body vibration or upper limb vibration, has been investigated increasingly as an exercise intervention for rehabilitation applications. However, there is a lack of evidence regarding the effects of graded isometric contractions superimposed on whole body vibration stimulation. Hence, the objective of this study was to quantify and analyse the effects of variations in the vibration parameters and contraction levels on the neuromuscular responses to isometric exercise superimposed on whole body vibration stimulation. Methods In this study, we assessed the ‘neuromuscular effects’ of graded isometric contractions, of 20%, 40%, 60%, 80% and 100% of maximum voluntary contraction, superimposed on whole body vibration stimulation (V) and control (C), i.e., no-vibration in 12 healthy volunteers. Vibration stimuli tested were 30 Hz and 50 Hz frequencies and 0.5 mm and 1.5 mm amplitude. Surface electromyographic activity of the vastus lateralis, vastus medialis and biceps femoris were measured during V and C conditions with electromyographic root mean square and electromyographic mean frequency values used to quantify muscle activity and their fatigue levels, respectively. Results Both the prime mover (vastus lateralis) and the antagonist (biceps femoris) displayed significantly higher (P < 0.05) electromyographic activity with the V than the C condition with varying percentage increases in EMG root-mean-square (EMGrms) values ranging from 20% to 200%. For both the vastus lateralis and biceps femoris, the increase in mean EMGrms values depended on the frequency, amplitude and muscle contraction level with 50 Hz–0.5 mm stimulation inducing the largest neuromuscular activity. Conclusions These results show that the isometric contraction superimposed on vibration stimulation leads to higher neuromuscular activity compared to isometric contraction alone in the lower limbs. The combination of the vibration frequency with the amplitude and the muscle tension together grades the final neuromuscular output.

2018 ◽  
Author(s):  
Amit N. Pujari ◽  
Richard D. Neilson ◽  
Marco Cardinale

AbstractBackgroundIndirect vibration stimulation i.e. whole body vibration or upper limb vibration, has been suggested increasingly as an effective exercise intervention for sports and rehabilitation applications. However, there is a lack of evidence regarding the effects of whole body vibration (WBV) stimulation superimposed to graded isometric contractions superimposed on. For this scope, we investigated the effects of WBV superimposed to graded isometric contractions in the lower limbs on muscle activation. We also assessed the agonist-antagonist co-activation during this type of exercise.Twelve healthy volunteers were exposed to WBV superimposed to graded isometric contractions, at 20, 40, 60, 80 and 100% of the maximum voluntary contractions (V) or just isometric contractions performed on a custom designed horizontal leg press Control (C). Tested stimulation consisted of 30Hzand 50Hz frequencies and 0.5mm and 1.5mm amplitudes. Surface electromyographic activity of Vastus Lateralis (VL), Vastus Medialis (VM) and Biceps Femoris (BF) were measured during V and C conditions. Co-contraction activity of agonist-antagonist muscles was also quantified. The trials were performed in random order.ResultsBoth the prime mover, (VL) and the antagonist, (BF) displayed significantly higher (P < 0.05) EMG activity with the V than the C condition. For both the VL and BF, the increase in mean EMGrms values depended on the frequency, amplitude and muscle contraction level with 50Hz-0.5mm stimulation inducing the largest neuromuscular activity. 50Hz-0.5mm V condition also led to co-activation ratios significantly (P< 0.05) higher at 40, 80 and 100% of MVC than the C condition.ConclusionsOur results show that the isometric contraction superimposed on vibration stimulation leads to higher neuromuscular activity compared to isometric contraction alone in the lower limbs. Compared to the control condition, the vibratory stimulation leads to higher agonist-antagonist co-activation of the muscles around the knee joint in all vibration conditions and effort levels. The combination of vibration magnitude (frequency and amplitude) and the level of muscle contraction affect neuromuscular activity rather than vibration frequency alone. Results of this study suggest that more parameters need to be taken into consideration when designing vibration exercise programs for sports and rehabilitation purposes.


2020 ◽  
Vol 10 (12) ◽  
pp. 4302
Author(s):  
Eloá Moreira-Marconi ◽  
Ygor Teixeira-Silva ◽  
Alexandre Gonçalves de Meirelles ◽  
Marcia Cristina Moura-Fernandes ◽  
Patrícia Lopes-Souza ◽  
...  

Knee osteoarthritis (KOA) can cause functional disability. Neuromuscular function is relevant in the development and progression of KOA. It can be evaluated by the analysis of the surface electromyography (sEMG), which has an important role in the understanding of KOA. Whole-body vibration (WBV) is an intervention suggested to treat KOA. The objective of this work was to verify the effectiveness of WBV on the functionality of lower limbs by the electromyographic profile of the vastus lateralis (VL) muscles during the five-repetition chair stand test (5CST) in patients with KOA. This was a two-period crossover trial study (8-week washout). Nineteen patients with KOA were allocated to the group submitted to WBV (WBVG), with peak-to-peak displacement of 2.5 to 7.5 mm, frequency from 5 to 14 Hz, and acceleration peak from 0.12 to 2.95 g, or to the control group (0 Hz) (2 days per week for 5 weeks). The 5CST and the sEMG of the VL during 5CST were evaluated before and after the interventions. Results: Significant differences in 5CST were evident only in WBVG (p = 0.018), showing a decrease of the execution time. The sEMG profile showed no significative difference. Therefore, only 10 sessions of WBV with comfortable posture can bring about improvement in functionality of KOA patients without alteration of the muscle excitation.


2021 ◽  
Vol 25 ◽  
pp. 1-5
Author(s):  
Sâmara R.A. Gomes ◽  
Liane B. Macedo ◽  
Daniel T. Borges ◽  
Karinna S.A. Costa ◽  
Samara A. Melo ◽  
...  

2015 ◽  
Vol 32 (3) ◽  
pp. 243-247 ◽  
Author(s):  
Arrigo Giombini ◽  
Federica Menotti ◽  
Luca Laudani ◽  
Alberto Piccinini ◽  
Federica Fagnani ◽  
...  

Dose-Response ◽  
2020 ◽  
Vol 18 (2) ◽  
pp. 155932582093126
Author(s):  
Riccardo Di Giminiani ◽  
Nadia Rucci ◽  
Lorenzo Capuano ◽  
Marco Ponzetti ◽  
Federica Aielli ◽  
...  

Objective. We aimed to investigate the acute residual hormonal, biochemical, and neuromuscular responses to a single session of individualized whole-body vibration (WBV) while maintaining a half-squat position. Methods. Twenty male sport science students voluntarily participated in the present study and were randomly assigned to an individualized WBV group (with the acceleration load determined for each participant) or an isometric group (ISOM). A double-blind, controlled parallel study design with repeated measures was employed. Results. Testosterone and growth hormone increased significantly over time in the WBV group ( P < .05 and P < .01, respectively; effect size [ES] ranged from 1.00 to 1.23), whereas cortisol increased over time in both groups ( P < .01; ES ranged from 1.04 and 1.36). Interleukin-6 and creatine kinase increased significantly over time only in the WBV group ( P < .05; ES = 1.07). The maximal voluntary contraction decreased significantly over time in the ISOM group ( P = .019; ES = 0.42), whereas in the WBV group, the decrease did not reach a significant level ( P = .05). The ratio of electromyographic activity and power decreased significantly over time in the WBV group ( P < .01; ES ranged from 0.57 to 0.72). Conclusion. Individualized WBV increased serum hormonal concentrations, muscle damage, and inflammation to levels similar to those induced by resistance training and hypertrophy exercises.


2018 ◽  
Vol 6 (9a) ◽  
pp. 43
Author(s):  
İlbilge Özsu ◽  
Hayri Ertan ◽  
Deniz Şimşek ◽  
Bahtiyar Özçaldiran ◽  
Cem Kurt

A limited number of acute whole body vibration (WBV) studies have investigated the effects of WBV treatments which were applied with different vibration frequencies and amplitude combinations on lower extremity muscle activation of well-trained athletes from different sports branches. To compare the effects of WBV on lower extremity muscle activation via Surface Electromyography (sEMG) of well-trained athletes from different sports branches (soccer, basketball and swimming) during static and dynamic squat exercises. sEMG activities of Tibialis Anterior (TA), Gastrocnemius Medialis (GM), Vastus Medialis (VM), Rectus Femoris (RF), Vastus Lateralis (VL) and Biceps Femoris (BF) muscles of 7 male soccer players, 7 male basketball players, and 6 male swimmers were recorded during WBV applied in static squat and dynamic squat positions with different frequencies (30-35-40 Hz) and amplitude (2-4 mm) combinations separated from each other by 5 min passive rest periods. Each combination was applied for 30 sec. The highest muscle activation was determined in TA of the swimmers compared to soccer players during static squat with 4mm-30Hz WBV application (p=0.027). The lowest muscle activation was also determined in VL of the swimmers compared to soccer players during static squat with 2mm-40Hz WBV (p=0.049). During dynamic squat with 4mm-40Hz WBV, the highest muscle activity was determined in RF of the basketball players compared to swimmers (p=0.030). However, dynamic squat with 2mm-40Hz WBV application gave rise to the lowest muscle activation in VL of the basketball players compared to soccer players (p=0.042). Well-trained athletes from different sports branches demonstrated different neuromuscular responses to acute WBV treatments. WBV during dynamic squatting which was applied with 4mm-40 Hz may be more beneficial in enhancing neuromuscular performance acutely for well-trained male athletes since it resulted in higher levels of muscular activation responses according to the present study.


2015 ◽  
Vol 72 (7) ◽  
pp. 646-650
Author(s):  
Milan Pantovic ◽  
Dejan Madic ◽  
Boris Popovic ◽  
Maja Batez ◽  
Jelena Obradovic

Introduction. Skeletal muscle atrophy is a common adaptation after major muscle lesion of m. biceps femoris that results in numerous health-sport related complications. Resistance strength training and whole-body vibration (WBV) have been recognized as an effective tool, which attenuates atrophy and evokes hypertrophy. Case report. We presented a 13-year-old boy with a lesion of m. biceps femoris and posttraumatic calcification sustained in soccer training session 6 month prior participation in this study. The patient underwent training 3 times a week for 7 weeks, including unilateral progressive WBV + resistance training (RT) of the right hamstrings muscle group using WBV and weights. Hamstrings muscle strength was measured using a Cybex isokinetic dynamometer. At the end of week 4, the patient peak torque value of the involved leg increased from 39% body weight (BW) to 72% BW and bilateral deficit decreased from -64% to -35%; at the end of week 7 the participant?s peak torque value of the involved leg increased from 72% BW to 98% BW and bilateral deficit decreased from -35% to -3%, respectively. Conclusion. Unilateral WBV + RT protocol evokes strength increase in the hamstrings muscle group. This case study suggests that adding WBV, as well as the RT program have to be considered in the total management of strength disbalance. Further studies are needed to verify the efficiency of WBV + RT protocol over the classic physical therapy exercise program.


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