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Effects of whole-body vibration on blood flow and neuromuscular activity in spinal cord injury

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Crossover trial. To investigate the effects of whole-body vibration (WBV) on muscular activity and blood flow velocity after different vibration treatments in patients with spinal cord injury (SCI). Research Center on Physical Disability (Spain). Eight individuals with SCI received six 3-min WBV treatments depending on a combination of frequency (10, 20 or 30 Hz) and protocol (constant, that is, three consecutive minutes of WBV, or fragmented, that is, three sets of 1 min of WBV with 1 min of rest between the sets). Femoral artery blood flow velocity was registered at minutes 1, 2 and 3 of WBV, and at minutes 1 and 2 after the end of the stimulus. Electromyography activity (EMG) of vastus lateralis (VL) and vastus medialis (VM) was registered at baseline and during WBV. Peak blood velocity (PBV) increased after 1, 2 and 3 min of WBV. The 10 Hz frequency did not alter blood flow, whereas the 20 Hz frequency increased PBV after 2 and 3 min of WBV, and the 30 Hz frequency increased PBV after 1, 2 and 3 min of WBV and during the first minute after the end of the stimulus. No protocol effect was observed for blood parameters. EMG activity of VL and VM increased independently of the applied frequency or protocol. WBV is an effective method to increase leg blood flow and to activate muscle mass in SCI patients, and could be considered to be incorporated in their rehabilitation programs.
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UNCORRECTED PROOF
ORIGINAL ARTICLE
Effects of whole-body vibration on blood flow and neuromuscular
activity in spinal cord injury
AJ Herrero
1,2
, H Mene
´ndez
1
, L Gil
1
, J Martı
´n
1
, T Martı
´n
1
, D Garcı
´a-Lo
´pez
2
,A
´Gil-Agudo
3
and PJ Marı
´n
1,2
1
Research Center on Physical Disability, ASPAYM Castilla y Leo
´n, Valladolid, Spain;
2
Laboratory of Physiology, Faculty of Health
Sciences, Miguel de Cervantes European University, Valladolid, Spain and
3
Biomechanics and Technical Aids Unit, Physical Medicine
and Rehabilitation Department, National Hospital for Spinal Cord Injury, SESCAM, Toledo, Spain
Study design: Crossover trial.
Objectives: To investigate the effects of whole-body vibration (WBV) on muscular activity and blood
flow velocity after different vibration treatments in patients with spinal cord injury (SCI).
Setting: Research Center on Physical Disability (Spain).
Methods: Eight individuals with SCI received six 3-min WBV treatments depending on a combination
of frequency (10, 20 or 30 Hz) and protocol (constant, that is, three consecutive minutes of WBV, or
fragmented, that is, three sets of 1 min of WBV with 1 min of rest between the sets). Femoral artery
blood flow velocity was registered at minutes 1, 2 and 3 of WBV, and at minutes 1 and 2 after the end of
the stimulus. Electromyography activity (EMG) of vastus lateralis (VL) and vastus medialis (VM) was
registered at baseline and during WBV.
Results: Peak blood velocity (PBV) increased after 1, 2 and 3 min of WBV. The 10Hz frequency did not
alter blood flow, whereas the 20 Hz frequency increased PBV after 2 and 3 min of WBV, and the 30 Hz
frequency increased PBV after 1, 2 and 3 min of WBV and during the first minute after the end of the
stimulus. No protocol effect was observed for blood parameters. EMG activity of VL and VM increased
independently of the applied frequency or protocol.
Conclusion: WBV is an effective method to increase leg blood flow and to activate muscle mass in SCI
patients, and could be considered to be incorporated in their rehabilitation programs.
Spinal Cord (2010) 0, 000–000. doi:10.1038/sc.2010.151
Keywords: vibration frequency; oscillating platform; Doppler ultrasound; electromyography;
rehabilitation
Introduction
Spinal cord injury (SCI) has muscular and vascular con-
sequences below the level of the injury.
1
Regarding muscular
changes, these patients suffer a dramatic loss of muscle
mass.
2
Immediately after the injury and in the following
months, there is a preferential atrophy of type 2 fibers, but
past 7–10 months post injury, a significant shift of type 1
fibers to type 2B has been observed.
3
Regarding vascular
changes, there is a reduction in the thigh blood flow,
4
femoral artery diameter,
1
vascular reactivity,
1
and capillary
alterations.
3
It has been proposed that changes in the muscle
vascular function are parallel to the skeletal muscle atrophy
in SCI subjects,
1
and both changes increase the risk of
cardiovascular disease
5
and the development of pressure
ulcers.
6
Therefore, part of the rehabilitation of SCI patients
should focus on the activation of muscular and vascular
systems.
4
The application of whole-body vibration (WBV) with
platforms has been shown to improve muscular
7,8
and
vascular
9–11
functions. These effects are strongly dependent
on the type of platform, protocols and vibration parameters
(that is, frequency).
7
Specifically, greater vibration frequen-
cies induce higher-muscle activity
8
and greater blood flow
11
than lower frequencies. Moreover, the most common
protocol used to apply WBV consists of short bouts (30–
90 s) with B60 s rest between the sets. The effects induced by
the application of longer bouts (3 min) on peripheral
circulation have been poorly investigated.
The previously mentioned benefits of WBV have been
observed in healthy subjects; however, no study has focused
on the effects of WBV on the muscle and vascular responses
of SCI patients. Thus, the purpose of this study was to
investigate the effects of WBV on muscular activity and
blood flow velocity after different vibration treatments in
SCI patients.
Received 14 July 2010; revised 22 September 2010; accepted 28 September
2010
Correspondence: Dr AJ Herrero, Laboratory of Physiology, Faculty of Health
Sciences, Miguel de Cervantes European University, c/Padre Julio Chevalier,
Valladolid 47012, Spain.
E-mail: jaherrero@oficinas.aspaymcyl.org
Spinal Cord
(2010), 1–6
&
2010 International Spinal Cord Society All rights reserved 1362-4393/10
$
32.00
www.nature.com/sc
UNCORRECTED PROOF
Materials and methods
Subjects
Eight patients (six males and two females) volunteered to
participate in the study. All the patients had SCI and used
wheelchair for their locomotion. All the subjects were
classified as ASIA A
Q1 by the American Spinal Injury Associa-
tion.Table 1 summarizes the characteristics of the sample.
All the subjects received rehabilitation ten 2-h sessions per
month, which consisted of standing position (or tilt
position), passive movements, low intensity resistance
training or electrotherapy, and physiotherapy treatment.
Experimental treatments were applied to the subjects before
their rehabilitation routines. Subjects did not allow their
sleeping, eating and drinking habits to change throughout
study participation. We certify that all applicable institu-
tional and governmental regulations concerning the ethical
use of human volunteers were followed during the course of
this research.
Experimental design
Each subject was assessed in eight different sessions. In the
first two sessions, subjects were familiarized with the testing
treatments and vibration stimulus. Both sessions were
carried out within the same week separated with at least
48 h. The other six sessions were carried out on Monday,
Wednesday and Friday during the following two weeks. In
each session, a random WBV treatment was applied. The six
WBV treatments arise from the combination of the inde-
pendent variables frequency (10, 20 or 30 Hz) and protocol
(constant or fragmented). WBV was applied for three
consecutive minutes during the constant protocol
Q2 , whereas
three cycles of 1 min of WBV and 1min of resting period
were applied during the fragmented protocol (Figure 1).
Treatment protocol
Once a subject came to the laboratory, he or she was laid down
and fixed to a tilt table with straps (Figure 2). In the distal part
of the tilt table, just beneath the feet, a vibration platform was
placed (Galileo Home, Galileo, Novotec, Germany). Knee
angle was of 601flexion (considering 01the full knee
extension). Subsequently, the tilt table was placed at 451and
the subject was kept in that position for a period of 10 min
before the application of WBV. All the subjects were familiar-
ized with the tilt table and the chosen angle as they usually
maintain this position in their rehabilitation routines. In that
position, the subject was prepared to register electromyogra-
phy activity (EMG) and ultrasound variables. The frequency of
vibration was set at 10, 20 or 30 Hz. The amplitude of the
vibration was set by the position of the feet on the WBV plate
at 5 mm (peak– peak). Feet were placed paralle l to each other
38 cm apart (measured from the midlines of the feet). The
patients were exposed to the vibration each day for a total of
3 min continuous (constant) or fragmented (three bouts 60 s
exposures, separated by 60 s rests).
Ultrasound measurements
Blood parameters were registered through an ultrasound
system (MyLab 25, Esaote, Genoa, Italy) using a pulsed color
Doppler with a linear array transducer (LA 523, 7.5–12 MHz;
length, 50 mm; Esaote, Genua, Italy) in the femoral arter y as
previously described.
11
Blood parameters were analyzed at
baseline, at the end of minutes 1, 2 and 3 of WBV, and at the
end of minutes 1 and 2 of recovery after the stop of WBV
(Figure 1). Each image recorded by the ultrasound system
corresponded to a period of 4 s. In that period, there were
between 3 and 5 beats, and the mean of these beats was
analyzed to obtain: mean and peak systolic blood velocities
(MBV and PBV, respectively), as well as heart rate.
NP G _ S C _ SC 2 01 0151
Table 1 Descriptive characteristics of the study sample
Gender Age (years) Height (m) Mass (Kg) Years after injury Level of lesion ASIA score PBV (cm s
1
)
a
MBV (cm s
1
)
a
1 M 41 1.74 83 24 T5 A 80.4±8.4 36.5±3.7
2 M 32 1.85 80 4 T8 A 66.6±3.5 33.0±3.9
3 M 32 1.98 94 5 C6 A 47.5±6.8 25.1±5.1
4 M 39 1.87 82 3 T3 A 59.4±6.1 30.1±3.5
5 M 33 1.74 78 3 C6 A 82.2±7.7 35.7±4.4
6 M 32 1.73 76 2 C6 A 83.2±6.9 42.8±6.0
7 F 35 1.63 78 6 L1 A 49.2±4.1 26.2±3.5
8 F 45 1.71 70 22 C5 A 66.5±5.0 34.8±3.2
Mean 36.1 1.78 80.1 8.6
s.d. 5.0 0.11 6.9 9.0
Abbreviations: MBV, mean blood velocity; PBV, peak blood velocity.
a
Mean±s.d. of the control period values of the six sessions.
Figure 1 Sketch of the experimental phase in 10 s intervals showing the fragmented (top) and constant (bottom) protocols.
Electromyography (diamonds) and blood parameters (circles) were registered.
Whole body vibration in spinal cord injury
AJ Herrero et al
2
Spinal Cord
UNCORRECTED PROOF
Surface electromyographic activity
Muscle activity of the vastus medialis (VM) and vastus
lateralis (VL) was measured using EMG. One set (two
measuring electrodes) of surface electrodes (Ag/AgCl, Skin-
tact, Austria
Q3 ) was placed longitudinally to the direction of
the muscle fibers and approximately halfway from the motor
point area to the distal part of the muscle. An inter-electrode
distance of 2 cm was maintained. Before electrode place-
ment, the area was shaved, abraded and cleaned with
isopropyl alcohol in order to reduce skin impedance until
it was lower than 5 kO. The location of the electrodes on the
skin was marked with permanent ink in order to ensure the
same placement throughout the different sessions.
Myoelectric raw signals were detected with a two-channel
EMG device (MyoTrac Infiniti, Thought Technology, Mon-
tre
´al, Canada). EMG data analysis was performed with a
specific software (BioGraph Infiniti, Thought Technology,
Montre
´al, Canada). The last 10 s corresponding to the
control period and corresponding to the third minute of
WBV application were chosen for data analysis by the
aforementioned software (Figure 1). EMG raw data was
averaged by root mean square (EMG
RMS
) in order to obtain
the average amplitude of the EMG signal. On the basis
of the frequency analysis, a bandwidth of ±0.8 Hz around
each harmonic was excluded from the root mean square
calculation.
Statistical analysis
The normality of the dependent variables was checked and
subsequently confirmed using the Kolmogorov–Smirnov
test. A three-way repeated-measures analysis of variance in
frequency, protocol, and time was applied to analyze EMG
and blood parameters. When a significant F-value was
achieved, pair-wise comparisons were performed using the
Bonferroni post hoc procedure. The reliability and variability
of blood parameters were assessed with intraclass correlation
coefficient and coefficients of variation (that is,
CV ¼s.d.*100/mean). A paired t-test was used to analyze
differences between both basal values. Statistical significance
was set at Pp0.05. Effect size statistic, Z,
2
was analyzed to
determine the magnitude of the effect independent of
sample size. Values are expressed as mean±s.d.
Results
Blood parameters
Table 2 shows the statistical significance and effect sizes
of the analysis of variances. PBV increased after 1, 2 and
3 min of WBV (11.3±10.3%, Po0.05, 19.0±13.5% and
23.0±14.4%, Po0.01, respectively). At 1 and 2 min after
the stop of the stimulus, PBV decreased at minute 3 of WBV
(14.4±9.3% and 14.0±8.5%, Po0.05, respectively) and
Q4
was similar to baseline values. Regarding baseline values, the
10 Hz frequency did not modify PBV, whereas the 20 Hz
frequency increased PBV after 2 and 3 min of WBV, and the
30 Hz frequency increased PBV after 1, 2 and 3 min of WBV as
well as during the first minute after the end of the stimulus
(Figure 3).
MBV increased after 1, 2 and 3 min of WBV (22.0±10.1%,
31.1±11.0% and 36.0±12.7%, Po0.001, respectively). Like-
wise, MBV remained increased in respect to baseline 1 min
after the stop of the WBV (14.0±8.1%, Po0.05). The 30 Hz
frequency increased MBV more than the 10 Hz frequency
(26.8±8.1% in respect to 13.0±8.7%, Po0.001). However,
no differences were observed between the increment with
20 Hz (17.0±11.3%) and the other two frequencies. All the
frequencies increased the MBV in respect to baseline at
minutes 1, 2 and 3 of WBV (Figure 4). Furthermore, 30 Hz
NP G _ S C _ SC 2 01 0151
Figure 2 Placement of the subject on the tilt table during the
application of the whole-body vibration.
Table 2 Summary of the main effects analyzed with the ANOVAs for the dependent variables: PBV, MBV, HR, VM EMG
RMS
and VL EMG
RMS
Time Frequency Time*frequency Time*protocol
PBV ICC ¼0.962; CV ¼5.6 Po0.001; Z
2
¼0.567 NS Po0.001; Z
2
¼0.342 NS
MBV ICC ¼0.888; CV ¼8.4 Po0.001; Z
2
¼0.756 Po0.01; Z
2
¼0.403 Po0.01; Z
2
¼0.254 NS
HR ICC ¼0.973; CV ¼2.8 NS NS NS NS
VM EMG
RMS
Po0.05; Z
2
¼0.237 NS Po0.05; Z
2
¼0.321 Po0.05; Z
2
¼0.268
VL EMG
RMS
Po0.05; Z
2
¼0.268 NS Po0.01; Z
2
¼0.275 Po0.05; Z
2
¼0.293
Abbreviations: ANOVA, analysis of variance; CV, coefficient of variation; HR, heart rate; ICC, intraclass correlation coefficient; MBV, mean blood velocity; NS, non-
significant; PBV, peak blood velocity; VL EMG
RMS,
vastus lateralis EMG activity; VM EMG
RMS,
vastus medialis EMG activity.
For each effect, the statistical significance and effect sizes are shown. For the blood parameters, the ICC and CV are shown.
At the beginning and at the end of the control period, blood parameters were registered to analyze their reliability and to establish baseline level as the mean of
both values.
Whole body vibration in spinal cord injury
AJ Herrero et al
3
Spinal Cord
UNCORRECTED PROOF
increased MBV to a higher extent than 10 Hz and maintained
the MBV increased in respect to baseline values 1 min after
the end of the WBV. No protocol effect was observed for PBV
or MBV.
EMG
Regarding VM, EMG
RMS
was higher after 3 min of WBV in
respect to baseline values (26.0±9.9 in respect to
18.9±2.8 mV, Po0.05). Likewise, for each frequency,
EMG
RMS
was higher after 3 min of WBV in respect to
baseline values, but no differences in baseline values nor
after WBV were observed among frequencies. For both
protocols, EMG
RMS
was higher after 3 min of WBV in respect
to baseline values, no differences in baseline values were
observed between protocols, but after WBV, EMG
RMS
was
greater after the constant protocol (28.5±5.7 in respect to
23.5±3.3 mV, Po0.05).
Regarding the VL, EMG
RMS
was higher after 3 min of WBV
in respect to baseline values (26.2±5.8 in respect to
15.2±1.1 mV, Po0.05). For each frequency, EMG
RMS
was
higher after 3 min of WBV in respect to baseline values, but
no differences in baseline values nor after WBV were
observed among frequencies. Finally, for both protocols,
EMG
RMS
was higher after 3 min of WBV in respect to baseline
values, no differences in baseline values were observed
between protocols, but after WBV, EMG
RMS
was greater after
the constant protocol (29.7±7.5 in respect to 22.8±4.3 mV,
Po0.05).
Discussion
The main findings of the present study were that WBV alone
can significantly increase leg blood flow velocity and EMG
activity in SCI patients. Moreover, higher frequencies (that
is, 20 and 30 Hz) produced greater increase in leg blood flow
velocity, although a tendency to evoke higher increase in
blood flow velocity was observed with 30 Hz, which also
maintained this variable above basal values after the stop of
the stimulus. No difference was observed regarding the
application of the WBV in a constant or fragmented
protocol.
Leg blood flow velocity was increased during the applica-
tion of WBV in SCI patients. However, the magnitude of
blood flow response observed in our study is lower than in
others carried out with healthy subjects.
9,11
Using an
oscillating platform, Kerschan-Schindl
9
found a two-fold
increase in mean blood flow in the popliteal artery
and Lythgo et al.
11
found a four-fold increase in mean
blood velocity in the femoral artery. These greater responses
in comparison to our results could be due to the fact that:
(1) the tilt table provides weight unloading, and as blood
flow highly correlates with work output,
12
a reduction in
work output owing to unloaded weight may result in a
smaller increase in blood flow;
10
(2) greater the active tissue,
higher the metabolic demand; as muscle weakness is a
feature of SCI,
2
the O
2
demand should be reduced and
subsequently would elicit a reduced response; and (3) the
reduced femoral artery diameter and blood flow observed in
SCI patients
1
would limit the hemodynamic response
to exercise.
WBV leads to an increased metabolic demand measured by
oxygen uptake in a linear relationship with vibration
frequency,
13
which is in agreement with our results. As
higher the frequency used, the greater increase in blood flow
velocity was observed. Although there was no difference in
this variable between 20 and 30 Hz, a trend to produce
higher increase with 30 Hz was detected. Furthermore, 30 Hz
maintained the PBV above basal values 1 min after the stop
of the vibration. This would recommend using 30 Hz in order
to analyze the long-term effects of the application of WBV in
SCI patients.
To the best of our knowledge, this is the first study to apply
WBV on a tilt table on SCI patients. Other ways of applying
NP G _ S C _ SC 2 01 0151
-5
0
5
10
15
20
25
30
35
40
45
50
55
60
65
Changes on Mean Blood Velocity (%)
Time (s)
Whole body vibration
10 Hz
20 Hz
30 Hz
***
***
***
a
***
a
**
b
***
aaa
**
**
*** ***
B 60 120 180 240 300
Figure 4 Time course changes on mean blood velocity depending
on the frequency during and after the application of 3 min of whole-
body vibration and three cycles of 1 min of vibration and 1 min
resting period. **
,
*** different from baseline at Po0.01 and 0.001,
respectively.
a, aaa, b
different from 10 Hz at Po0.05, Po0.001 and
P¼0.08, respectively.
-5
0
5
10
15
20
25
30
35
40
45
50
Changes on Peak Blood Velocity (%)
Time (s)
Whole body vibration
10 Hz
20 Hz
30 Hz
**
**
**
**
a
**
**
aaa
B60
120 180 240 300
Figure 3 Time course changes on PBV depending on the frequency
during and after the application of 3min of whole-body vibration
and three cycles of 1 min of vibration and 1min of resting period.
** different from baseline at Po0.01.
a, aaa
different from 10 Hz at
Po0.05 and Po0.001, respectively.
Whole body vibration in spinal cord injury
AJ Herrero et al
4
Spinal Cord
UNCORRECTED PROOF
WBV on SCI patients have been through partial standing or
standing on the platform with the help of a specific device.
14
In the present study, the tilt table was fixed at an angle of 451
for the following reasons: (1) this angle unloads part of the
weight of the subject but less than a sitting position; (2) SCI
patients can experience episodes of orthostatic hypotension
and can faint if angles near to the vertical are reached
15
and
(3) all the participants were familiarized with this angle as
they used to maintain this position during 30 min in their
rehabilitation routines.
The improvement of lower-extremity circulation is a goal
of the rehabilitation of SCI patients.
4
Some of the traditional
exercises performed to achieve this goal have been passive
leg movements and passive cycling; however, there is
evidence supporting that these methods do not increase
leg blood flow in SCI patients.
16
As well as increasing
blood flow, the application of WBV during supine bed rest
for 52 days avoided a decrease of the diameter of the
common femoral artery in respect to a control group.
17
This
observation has not been reported in SCI patients but future
studies that combine WBV and Doppler ultrasound measures
should contrast if this preservation is possible in this
collective.
EMG
RMS
of VL and VM increased after the application of
WBV independently of frequency or protocol. In healthy
subjects, the same increases have been reported using
frequencies between 15 and 30 Hz.
18
In SCI patients,
we have not found any research that combines WBV and
EMG recordings, nevertheless the application of punctual
vibration on thigh muscles during locomotion increased the
muscle activity of SCI patients.
19
This increase in the
EMG
RMS
could be due to the fact that mechanical vibrations
applied to the muscle or tendon stimulate sensory
receptors and that activation of muscle spindles facilitates
the activation of a-motoneurons, leading to tonic vibration
reflex.
20
In our study, no significant difference was
noted depending on the frequency. It could be expected
that 30 Hz would increase EMG amplitude more than
10 Hz, as the acceleration of the platform is higher as the
frequency increases. Furthermore, in healthy subjects, great-
er EMG activity with high-frequency WBV training (40 and
45 Hz) has been reported when compared with lower
frequencies (25 and 30 Hz).
8
In our study, the lack of
differences in the EMG activity between frequencies could
be due to the reduced EMG response of SCI patients in
respect to healthy subjects,
21
as well as to the marked
difference in the EMG patterns among SCI subjects;
21
therefore, this lack of statistical significance could be due
to a type II error.
In conclusion, WBV represents an option to induce a reflex
muscle contraction in subjects with difficulties or inability to
evoke voluntary contractions such as SCI patients. Our
results show that WBV is an effective method to increase leg
blood flow and to activate muscle mass in these patients, and
could, therefore, be considered to be incorporated in
rehabilitation programs of this collective. Moreover, the
methodology proposed to apply SCI through the use of a tilt
table has been safe, easy to perform and welcomed by the
subjects and therapists.
Conflict of interest
The authors declare no conflict of interest.
Acknowledgements
This work was supported in part by a grant from the
IMSERSO (37/2008).
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Spinal Cord
... Although it was demonstrated that WBV could alter blood flow in the legs of healthy young adults (Kerschan-Schindl et al., 2001;Lythgo et al., 2009) and increase blood flow and activating muscles in the legs of patients with spinal cord injury (Herrero et al., 2011), the effectiveness of vibration stimulation in improving blood flow in the lower limbs and reducing hip and knee contracture in children with MMC is unknown. The purpose of this study was to investigate the effect of WBV training used in conjunction with conventional PT (i.e., WBV-assisted training) on blood flow in the lower limbs and the range of motion (ROM) of lower limb joints in children with MMC. ...
... WBV training with high-frequency/low-amplitude vibration in healthy individuals has been shown to induce muscle activity (Marin and Rhea, 2010), increase blood flow (Kerschan-Schindl et al., 2001), and enhance vascular functioning (Lythgo et al., 2009). In adult patients with spinal cord injury, WBV training increased both muscle mass and blood flow in the leg (Herrero et al., 2011). However, as there have been no studies investigating the effect of WBV on blood flow in the lower limbs of children with MMC, we are unable to validate our findings through comparisons with other work. ...
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This study investigated the effectiveness of whole-body vibration (WBV) training incorporated into a conventional physiotherapy (PT) program (WBV-assisted training) in improving blood flow in the lower limbs and range of motion in the lower limb joints of children with myelomeningocele (MMC). A total of 31 children with MMC (7–15 years old) underwent a 6 weeks treatment program consisting of 2 weeks of conventional PT followed by 4 weeks of WBV-assisted training. The assessment comprised two parts: evaluation of lower limb joint range of motion and Doppler ultrasonography of the superficial femoral, popliteal, and anterior tibial arteries and was performed three times for each of the participants (at baseline, after 10 sessions of PT but before WBV-assisted training, and after 20 sessions of WBV-assisted training). Our results showed that WBV-assisted training significantly improved lower limb circulation in patients with MMC, increasing velocity and reducing resistivity in all tested arteries. Moreover, WBV-assisted training alleviated lower-extremity contractures, especially of the knee. Thus, WBV-assisted training is effective as an adjunctive rehabilitation program for improving functional mobility in children with MMC.
... Whole-body vibration can induce sEMG activity of lower limb muscles independently of the applied frequency or protocol (Herrero et al., 2011), while similar results were evident for upper limb muscles (Da Silva et al., 2016). Nonetheless, long-term effects of whole-body vibration on muscle activation were not observed (Masani et al., 2014). ...
Article
Objective Surface electromyography (sEMG) is a common electrophysiological assessment used in clinical trials in individuals with spinal cord injury (SCI). This scoping review summarizes the most common sEMG techniques used to address clinically relevant neurorehabilitation questions. We focused on the role of sEMG assessments in the clinical practice and research studies on neurorehabilitation after SCI, and how sEMG reflects the changes observed with rehabilitation. Additionally, this review emphasizes the limitations and pitfalls of the sEMG assessments in the field of neurorehabilitation after SCI. Methods A comprehensive search of Medline (Ovid), Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Embase, Emcare, Cumulative Index to Nursing & Allied Health Literature, and PubMed was conducted to find peer-reviewed journal articles that included individuals post-SCI that participated in neurorehabilitation interventions using sEMG assessments. This is a scoping review using a systematic search (hybrid review). Results Of 4522 references captured in the primary database searches, 100 references were selected and included in the scoping review. The main focus of the studies was on neurorehabilitation using sEMG biofeedback, brain stimulation, locomotor training, neuromuscular electrical stimulation (NMES), paired-pulse stimulation, pharmacology, posture and balance training, spinal cord stimulation, upper limb training, vibration, and photobiomodulation. Conclusions Most studies employed sEMG amplitude to understand the effects of neurorehabilitation on muscle activation during volitional efforts or reduction of spontaneous muscle activity (e.g., spasms, spasticity, and hypertonia). Further studies are needed to understand the long-term reliability of sEMG amplitude, to circumvent normalization issues, and to provide a deeper physiological background to the different sEMG analyses. Significance This scoping review reveals the potential of sEMG in exploring promising neurorehabilitation strategies following SCI and discusses the barriers limiting its widespread use in the clinic.
... Esta resposta neuromuscular traduz um aumento no recrutamento de unidades motoras durante contrações voluntárias submáximas (Rittweger, 2010;Krol et al., 2011). Assim, ocorre uma indução maior da atividade muscular (Rittweger, 2010) acompanhado pelo aumento na oxigenação tecidual (Coza, Nigg e Dunn, 2011) e no fluxo sanguíneo muscular (Herrero et al., 2011). Desta forma, há o interesse nos EVCI como uma possibilidade adicional a ser incorporada no grupo de métodos de tratamento tradicionais de exercícios (Delecluse, Roelants e Verschueren, 2003). ...
... Apart from our studies, there has been no other investigation on the effects of WBV on the blood flow of the lower limbs of children with MMC; thus, it is not possible to compare our findings with other studies. Nonetheless, previous studies may have confirmed the positive influence on clinical features in individuals with MMC [8]. Specifically, these studies investigated the effects of WBV therapy on blood flow velocity and on muscular activity in adult patients with spinal cord injury and reported that WBV was an effective method to increase blood flow to the leg and could also activate the formation of muscle mass in these patients [9]. ...
Article
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The objective of the present study was to determine the effectiveness of a three-week Whole-Body Vibration (WBV) training on the vascular blood flow of the lower limbs in children with myelomeningocele. The secondary goal was to evaluate the effect of WBV on the ROM of lower limb joints in this population. A total of 30 children with MMC (7–16 years old) were enrolled in the study. Children were randomly allocated to two groups of equal numbers, using an envelope code. The experimental group underwent a 3-week WBV training, while the control group received a 3-week conventional physiotherapy (PT) program. The examination consisted of two parts: (1) Doppler USG examination of the lower limb vascular blood flow; (2) evaluation of ROM. The results obtained revealed three main findings. First, WBV training effectively improved blood flow by increasing flow velocities in all tested arteries, while the impact of the PT program was limited to a single parameter. Second, WBV training effectively improved vascular resistance in arteries of the lower legs, while the PT program did not achieve any significant differences. Third, both types of treatment intervention significantly improved ROM in all joints of the lower limbs in MMC participants.
... Thus, if anticoagulant therapy is necessary, a possibility is that the concomitant administration of DOACs and nintedanib-especially considering drug-monitored therapy-has been used in patients at high risk of bleeding complications [14]. These effects related to the DOAC/nintedanib may relevant if it is proposed an intervention with whole-body vibration (WBV) exercise due this type of intervention has been used to improve peripheral circulation in elderly individuals [15], the endothelial function in elderly patients with cardiovascular diseases [16], blood flow kinetics in different populations [17], blood flow in the legs of healthy young adults [18,19], and blood flow and activating muscles in the legs of patients with spinal cord injury [20]. Moreover, Szopa et al., 2021 [21] reported that WBV exercise improved lower limb cir-culation in myelomeningocele patients, increasing velocity and reducing resistivity in all tested arteries. ...
Article
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COVID-19 infection frequently leaves the infected subjects with impairments of multi-organs, the so-called post COVID-19 syndrome, which needs to be adequately addressed. The perspective of this narrative review is to verify the possible role of whole-body vibration exercise in the post-COVID-19 rehabilitation of these patients. Publications reporting the use of WBV exercises to counteract fatigue, muscle weakness, neurological manifestations, pain, quality of life, quality of sleep, lung commitments, and mental conditions in different clinical conditions were selected. Considering all the findings described in the current review, it seems that WBV exercise might be potentially useful and effective in the rehabilitation of post COVID-19 syndrome, being able to positively influence fatigue, muscle weakness, and quality of life without any side-effects. Controlled studies are mandatory to define the best protocols to be proposed, which need to be tailored to the individual and clinical characteristics.
... The effect can be different depending on different vibration frequencies, amplitudes, durations, regional or whole body, etc. When high-frequency (> 20 Hz) vibration is applied at rest (Lohman et al., 2011;Sanchez-Gonzalez et al., 2012;Wong et al., 2012) or during exercise (Figueroa et al., 2011;Kerschan-Schindl et al., 2001), arteriolar relaxation (Herrero et al., 2011;Kerschan-Schindl et al., 2001;Koutnik et al., 2014;Sanchez-Gonzalez et al., 2012;Wong et al., 2012) and skin microvascular expansion (Lohman et al., 2011) were observed by arterial pulse wave analysis and laser Doppler. There are few investigations concerning the effects of low-frequency (< 20 Hz) vibration on the cardiovascular system. ...
Article
It is important to use short breaks to accelerate post-exercise recovery in sports. Previous studies have revealed that vibration can reduce post-exercise muscle soreness. However, there is still high heterogeneity in the effects of vibration on cardiovascular autonomic activities, and most studies to date have focused on high-frequency vibration. This study aimed to investigate the effect of low-frequency lower-body vibration (LBV) on post-exercise changes in heart rate variability and peripheral arterial tone. Ten men and 9 women aged 20 to 25 were recruited for this study. Each subject visited the testing room three times with at least 2 days in between. Each time, the subject received one of the three different vibration frequencies (0, 5, and 15 Hz) in a random order in the sitting position for 10 minutes. LBV was performed immediately after a static standing (control) test and 3-min-step test. Heart rate variability and digital volume pulse wave were recorded during the vibration phase (V1: vibration 0-5 minutes; V2: 6-10 minutes) and the recovery phase (Rc1: recovery phase 11-15 minutes; Rc2: 16-20 minutes). The result of digital pulse wave analysis showed that the reflection index (RI) under 15 Hz decreased during V1. Heart rate of the 15-Hz group also decreased during Rc1 and Rc2. According to the analysis of heart rate variability, low-frequency power/high-frequency power (LF/HF) decreased and normalized high-frequency power (nHF) increased during V2, Rc1 and Rc2 under 15 Hz and, during Rc2 under 5 Hz vibration. This study confirmed that the application of low-frequency LBV after exercise can reduce peripheral vascular tone, accelerate heart rate recovery, decrease cardiac sympathetic nerve activity, and promote parasympathetic nerve activity. The effect was more pronounced at 15 Hz than at 5 Hz. The findings provide a method to accelerate cardiovascular autonomic recovery after exercise.
... [59][60][61] It has been promoted as an effective method to induce a reflex muscle contraction in subjects with difficulties to evoke voluntary contractions. 62 The mechanism behind the improvements may be that the vibration stimuli excite muscle spindles, and activate the tonic vibration reflex, which acts on alpha-motor neurons. This could potentially engage central motor command, which facilitates increased muscle activation and voluntary movements. ...
Article
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Objective To systematically review and summarise the evidence for the effects of neuromuscular training compared with any other therapy (conventional training/sham) on knee proprioception following anterior cruciate ligament (ACL) injury. Design Systematic Review. Data sources PubMed, CINAHL, SPORTDiscus, AMED, Scopus and Physical Education Index were searched from inception to February 2020. Eligibility criteria Randomised controlled trials (RCTs) and controlled clinical trials investigating the effects of neuromuscular training on knee-specific proprioception tests following a unilateral ACL injury were included. Data extraction and synthesis Two reviewers independently screened and extracted data and assessed risk of bias of the eligible studies using the Cochrane risk of bias 2 tool. Overall certainty in evidence was determined using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) tool. Results Of 2706 articles retrieved, only 9 RCTs, comprising 327 individuals with an ACL reconstruction (ACLR), met the inclusion criteria. Neuromuscular training interventions varied across studies: whole body vibration therapy, Nintendo-Wii-Fit training, balance training, sport-specific exercises, backward walking, etc. Outcome measures included joint position sense (JPS; n=7), thresholds to detect passive motion (TTDPM; n=3) or quadriceps force control (QFC; n=1). Overall, between-group mean differences indicated inconsistent findings with an increase or decrease of errors associated with JPS by ≤2°, TTDPM by ≤1.5° and QFC by ≤6 Nm in the ACLR knee following neuromuscular training. Owing to serious concerns with three or more GRADE domains (risk of bias, inconsistency, indirectness or imprecision associated with the findings) for each outcome of interest across studies, the certainty of evidence was very low. Conclusions The heterogeneity of interventions, methodological limitations, inconsistency of effects (on JPS/TTDPM/QFC) preclude recommendation of one optimal neuromuscular training intervention for improving proprioception following ACL injury in clinical practice. There is a need for methodologically robust RCTs with homogenous populations with ACL injury (managed conservatively or with reconstruction), novel/well-designed neuromuscular training and valid proprioception assessments, which also seem to be lacking. PROSPERO registration number CRD42018107349.
... WBV have been used as an active recovery because produce reflex neuromuscular stimulation, (Herrero et al., 2011) causing a lower heart rate during recovery time that could be associated by an increased venous return as result of an active muscle pump (Takahashi et al., 2005). ...
Article
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In the last years the nervous and cardiovascular response to exercise has taken on an important relevance, both in sport and health field. In this line, accelerating cardiovascular appears to play a key role in various sports fields. The study aims to examine and compare the acute effect of whole-body vibration (WBV) on cardiac autonomic response after maximal exercise in university runners and physical education student. Twenty men participated in a cross-over study, 10 university runners team (UR) and 10 physical education student (PES) with ages around 18 to 24 years. In each condition, was perform an incremental cardiopulmonary exercise test followed (i) active recovery time using WBV (25 Hz and peak displacement of four mm) and (ii) passive recovery period (no WBV; 0 Hz-0 mm), separated by seven days. Active recovery consisted in one minute seated using WBV and one minute no WBV by six times (12 minutes) more five minutes of passive recovery, and passive recovery consisted in 17 min seated on platform without vibration. Active recovery had significant differences compare to passive recovery (P<0.05). Furthermore, in active recovery, PES had better heart rate response than UR group, however results were not significative. There was not a clear relation between the lineal components of heart rate variability (HRV) in our results. WBV has positive effect in participant's recovery, however, is necessary establish protocols about the intensities and time adequate for allow accelerate recovery the parasympathetic reactivity, for that reason yet can't conclude clearly respect to the more effectivity intensity WBV depending to characteristic of subject. Resumen. En los últimos años la respuesta nerviosa y cardiovascular al ejercicio ha adquirido una relevancia importante, tanto en el ámbito del deporte como de la salud. Por tanto, la aceleración de la recuperación cardiovascular parece desempeñar un papel clave en varios campos. El objetivo del estudio es analizar y comparar el efecto agudo de la vibración de cuerpo completo (VCC), en la respuesta cardíaca autónoma después del ejercicio máximo en corredores universitarios (CU) y estudiantes de educación física (EEF). Veinte hombres participaron en un estudio cruzado, 10 CU y 10 EEF con edades entre 18 y 24 años. En cada evaluación, se realizó una prueba cardiopulmonar incremental seguida de (i) tiempo de recuperación activa usando VCC (25 Hz y desplazamiento máx. de cuatro mm) y (ii) período de recuperación pasiva (sin VCC; 0 Hz-0 mm), separados por siete días. La recuperación activa consistió en un minuto sentado usando WBV y un minuto sin WBV seis veces (12 min), más cinco minutos de recuperación pasiva; la recuperación pasiva y esta consistió en 17 minutos sentado en plataforma sin vibración. La recuperación activa tuvo diferencias significativas en comparación con recuperación pasiva (p <0.05). Además, en recuperación activa, EEF tuvo una mejor respuesta de frecuencia cardíaca que el grupo CU, sin embargo, los resultados no fueron significativos. Por último, no se logró establecer una relación clara entre los componentes lineales de la variabilidad del ritmo cardiaco (VRC) en nuestros resultados. La VCC tiene un efecto positivo en la recuperación de los sujetos, sin embargo, es necesario establecer protocolos sobre las intensidades y tiempo adecuado para permitir acelerar la recuperación de la reactividad parasimpática, por esa razón aún no se puede concluir claramente respecto al mejor protocolo VVC dependiendo de la característica del sujeto.
... Whole body vibrations at low frequencies (10-30 Hz) are an effective method to increase a leg's blood flow and to activate a muscle mass in patients [14]. They attributed the increased blood flow to the myogenic response in vasculature. ...
Article
Background: An automatic massage produces health improving effects. After a single automatic massage, patients admit a feeling of invigoration, and a sense of relaxation. Some quantitative characteristics of physical effects produced by the automatic massage on the body, including the work of a heart were unavailable at that moment. Objective: This study aims to find a quantitative impact of periodic low frequency mechanical vibrations on the relative change in a heart stroke volume. Material and methods: In this experimental study, the patients were exposed to the low frequency (12 Hz) planar mechanical vibrations. The blood pressures were measured before and after the automatic massage. Based on the measured values in the arterial blood pressure, a relative change in a stroke volume (SV) in patients was calculated. Results: The increased systolic blood pressure was 6.3±2.0 mm Hg in women and 11.1±2.7 mm Hg in men. The increased diastolic pressure was 1.9±1.2 mm Hg in women, and 4.9±1.5 mm Hg in men. The minor increase in heart rate for women was 1.2±1.0 beats per minute, and 1.2±2.0 beats per minute for men. The assessment of stroke volume changes provided 9.6% and 7.1% increase during systole and diastole in male patients, respectively, and corresponding 6.7% and 4.7% increases for female patients. Conclusion: The results of our work confirmed an increase in the systolic and diastolic blood pressures under the influence of periodic mechanical vibration of low frequency. We believe that the registered increase in blood pressure is a proof of the increase in a stroke volume (SV).
... Many studies show the benefits of full-body vibration therapy (WBV or whole-body vibration) in different diseases. Herrero et al. (26) assessed the effects of WBV on muscle activity, on the speed of blood flow in patients with spinal cord injury. WBV is effective in increasing leg, and restoring, muscle mass in patients with spinal injury. ...
Article
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Objective The primary aim of this review is to verify whether the warning against the use of electromedical instruments in the cosmetic professional or medical cancer patient settings is consistent with evident oncological risks supported by experimental in vitro / in vivo studies or anecdotal clinical reports, or any other reasonable statement. Methods MEDLINE, PubMed, Embase, AMED, Ovid, Cochrane Controlled Trials Register, and Google Scholar databases were electronically searched. Data relating to research design, sample population, type of electro-cosmetic devices used, were extracted. Results The search strategy identified 50 studies, 30 of which were potentially relevant. Conclusions Our research is in favor of moderate periodical use of cosmetic medical devices in patients bearing tumors, in any stage, like in healthy people. Special consideration is dedicated to massage, manipulation, and pressure delivery upon the cytoskeleton of cancer cells that has proven to be sensitive to mechanical stress at least in some specific locally relapsing cancers such as osteosarcoma.
Article
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Bone mineral density (BMD) loss is a medical concern for individuals with spinal cord injury (SCI). Concerns related to osteoporosis have lead researchers to use various interventions to address BMD loss within this population. Whole body vibration (WBV) has been reported to improve BMD for postmenopausal women and suggested for SCI. The purpose of this case study was to identify the effects of WBV on BMD for an individual with SCI. There were three progressive phases (standing only, partial standing, and combined stand with vibration), each lasting 10 weeks. Using the least significant change calculation, significant positive changes in BMD were reported at the trunk (0.46 g/cm(2)) and spine (.093 g/cm(2)) for phase 3 only. Increases in leg lean tissue mass and reduction in total body fat were noted in all three phases.
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The purpose of this meta-analysis was to attempt to gain a clear picture of the magnitude of strength improvements expected after acute and chronic vibration training and to identify specific factors that influence the treatment effects. Studies employing a strength training intervention and containing data necessary to calculate effect size (ES) were included in the analysis. A total of 31 studies met the inclusion criterion. Analysis of ES demonstrated that the type of vibration platform employed is a moderator of the treatment effect of vibration on strength development. Differences were noted in both acute and chronic changes in muscle strength when vertical vibration platforms are compared with oscillating platforms. Vertical platforms elicit a significantly larger treatment effect for chronic adaptations (ES = 1.24) compared with oscillating platforms (ES = -0.13). However, oscillating platforms elicit a greater treatment effect for acute effects (ES = 0.24) compared with vertical platforms (ES = -0.07). The data also show that gender, training status, and exercise protocol are moderators of the response to vibration exercise for strength development (vertical platforms). Based on the overall analysis, it is apparent that vibration exercise can be effective at eliciting chronic muscle strength adaptations. The vibration exercise can be used by exercise professionals to enhance muscular strength.
Article
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The effect of whole-body vibration dosage on leg blood flow was investigated. Nine healthy young adult males completed a set of 14 random vibration and non-vibration exercise bouts whilst squatting on a Galileo 900 plate. Six vibration frequencies ranging from 5 to 30 Hz (5 Hz increments) were used in combination with a 2.5 mm and 4.5 mm amplitude to produce twelve 1-min vibration bouts. Subjects also completed two 1-min bouts where no vibration was applied. Systolic and diastolic diameters of the common femoral artery and blood cell velocity were measured by an echo Doppler ultrasound in a standing or rest condition prior to the bouts and during and after each bout. Repeated measures MANOVAs were used in the statistical analysis. Compared with the standing condition, the exercise bouts produced a four-fold increase in mean blood cell velocity (P<0.001) and a two-fold increase in peak blood cell velocity (P<0.001). Compared to the non-vibration bouts, frequencies of 10-30 Hz increased mean blood cell velocity by approximately 33% (P<0.01) whereas 20-30 Hz increased peak blood cell velocity by approximately 27% (P<0.01). Amplitude was additive to frequency but only achieved significance at 30 Hz (P<0.05). Compared with the standing condition, squatting alone produced significant increases in mean and peak blood cell velocity (P<0.001). The results show leg blood flow increased during the squat or non-vibration bouts and systematically increased with frequency in the vibration bouts.
Article
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The purpose of this study was to determine the effect of vertical whole-body vibration (WBV) on heart rate (HR), mean arterial pressure (MAP), femoral artery blood flow (FBF), and leg skin temperature (LSk(temp)) during static exercise. These parameters were examined: seated next to the WBV device (passive, unloaded), with feet secured onto the WBV platform (knees 90 degrees flexion) and while standing in a semi-squat position (static, loaded, knees 120 degrees flexion); both with and without WBV. Conditions involved 1 min bouts separated by 1 min rest, repeated 15 times followed by 10 min recovery. WBV in the seated condition had no effect on the responses examined. The static semi-squat without WBV increased MAP 9 mmHg (P < 0.05) with no significant effect on HR, FBF, or LSk(temp). Similarly, WBV static semi-squat increased MAP 8-14 mmHg (P < 0.05), FBF 135-180 mL/min, and LSk(temp) 1.8-3.1 degrees C (P < 0.05). However, only the LSk(temp) was increased above the no-WBV semi-squat position (P < 0.05). The addition of WBV to repeated intermittent static semi-squats does not appear to be a significant cardiovascular stressor.
Article
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The brain motor control assessment (BMCA) protocol is a comprehensive multichannel surface EMG recording used to characterize motor control features in persons with upper motor neuron dysfunction. Key information is contained in the overall temporal pattern of motor unit activity, observed in the EMG (RMS) envelope. In paralysis, a rudimentary form of suprasegmental control of tonic and phasic reflexes can be demonstrated. EMG patterns evoked by voluntary and passive maneuvers and by volitional modulation of reflex responses reveal features of motor control not apparent in the clinical examination. Such subclinical findings may explain paradoxically different responses in apparently similar SCI subjects, and may be used to monitor spontaneous or induced changes. The recording protocol, examples of EMG patterns, and their prevalence in 40 spinal cord injured (SCI) subjects are presented, and compared with 5 healthy subjects.
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To test whether lower extremity blood flow and hyperemic responses to vascular occlusion differ among electrically stimulated exercise trained and sedentary tetraplegic persons and subjects without tetraplegia (control). Blinded cross-sectional comparison, control group. Academic medical center. Ten sedentary tetraplegic men, 10 tetraplegic persons previously habituated to electrically stimulated cycling exercise for 0.4 to 7 years, and 10 nondisabled controls. Subjects underwent quantitative Doppler ultrasound examination of the common femoral artery (CFA). End-diastolic arterial images and arterial flow-velocity profiles obtained at rest and following five minutes of suprasystolic thigh occlusion were computer digitized for analysis of heart rate (HR), CFA peak systolic velocity (PSV), CFA cross-sectional area (CSA), flow velocity integral (FVI), and computed CFA inflow volume (IV). No group main effects were observed for resting HR or FVI. At rest, trained tetraplegic men had 14.9% greater PSV, 29.8% larger CSA, and 51.3% greater IV (p values < .05) than sedentary tetraplegic subjects. Resting PSV and IV of the trained subjects did not differ from controls, although CSA was smaller than controls (p < .05). Following occlusion, PSV, CSA, and IV averaged 16.5%, 33.4%, and 65.1% greater for trained tetraplegics persons, respectively, than sedentary tetraplegic subjects (p values < .05). Only CSA differed between the control and the trained groups (p < .05). Tetraplegic persons conditioned by electrically stimulated cycling have greater lower extremity blood flow and hyperemic responses to occlusion than do their sedentary counterparts.
Article
The purpose of this study was to determine whether the muscle vibration applied to the quadriceps has potential for augmenting muscle activity during gait in spinal cord injured (SCI) individuals. The effects of muscle vibration on muscle activity during robotic-assisted walking were measured in 11 subjects with spinal cord injury (SCI) that could tolerate weight-supported walking, along with five neurologically intact individuals. Electromyographic (EMG) recordings were made from the tibialis anterior (TA), medial gastrocnemius (MG), rectus femoris (RF), vastus lateralis (VL), and medial hamstrings (MH) during gait. Vibration was applied to the anterior mid-thigh using a custom vibrator oscillating at 80 Hz. Five vibratory conditions were tested per session including vibration applied during: (1) swing phase, (2) stance phase, (3) stance-swing transitions, (4) swing-stance transitions, and (5) throughout the entire gait cycle. During all vibration conditions, a significant increase in EMG activity was observed across both SCI and control groups in the RF, VL, and MH of the ipsilateral leg. In the SCI subjects, the VL demonstrated a shift toward more appropriate muscle timing when vibration was applied during stance phase and transition to stance of the gait cycle. These observations suggest that the sensory feedback from quadriceps vibration caused increased muscle excitation that resulted in phase-dependent changes in the timing of muscle activation during gait.
Article
The prevalence of diseases associated with obesity, such as cardiovascular disease and diabetes mellitus, is higher in the spinal cord injury (SCI) population. Specifically, the mortality rate for cardiovascular disease is 228% higher in the SCI population. In addition, 100% of SCI individuals have osteoporosis in the paralysed extremities. These diseases are related to physical activity level, the level of the spinal cord lesion, and time post injury. Physically active SCI men and women have above-average fat mass (16 to 24% and 24 to 32%, respectively, compared with 15% for able-bodied men and 23% for able-bodied women), while sedentary SCI individuals have 'at-risk' levels of body fat (above 25% and 32%, respectively). The proportions and densities of the 3 main constituents comprising the fat-free body (mineral, protein and water) are altered following SCI. Bone mineral content decreases by 25 to 50%, and the magnitude of reduction is dependent on the level, completeness and duration of SCI. Because of denervation resulting in skeletal muscle atrophy, total body protein reduces by 30%, and total body water relative to bodyweight decreases by 15% following SCI. Indirect methods based on 2-component body composition models assume constant proportions and densities of mineral, protein, and water in the fat-free body. As a result, prediction equations based on 2-component models yield invalid estimates of fat and fat-free mass in the SCI population. Therefore, future research needs to directly quantify the proportions and densities of the constituents of the fat-free body in the SCI population relative to age, sex, physical activity level, level of the spinal cord lesion and time post injury, and to develop equations based on multicomponent body composition models.