**2.3. Our previous study 2**

When vibration stimulation is applied on skeletal muscle, the amount of output and muscle activity of the stimulated skeletal muscle is decreased. This finding should help to bring on a change in the pattern of muscle activity during action (Table 1).

on the nervous system. It is anticipated that further effects that vibration stimulation has on

Evoked EMG Makes Measurement of Muscle Tone Possible by Analysis of the H/M Ratio

http://dx.doi.org/10.5772/55783

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*2.4.2. Muscle activity and the amount of skeletal muscle output are reduced by more than 20 minutes*

Vibration stimulation on a sustained maximum muscle contraction case can reduce the firing frequency of the nerve cells involved in the maximum contraction, and subsequently the muscle output will decrease. In addition, more than 20 minutes of vibration stimulation on quadriceps femoris muscle can bring on a reduction in the peak torque and integrated EMG. If you apply these findings clinically, it is possible to suppress the excessive and abnormal muscle activity that occurs as a compensatory motion during action, and subsequently to let

However, in patients with osteoarthritis of the knee and also in patients who have undergone ACL reconstruction and therefore need onerous training, no decrease of the peak torque and integrated EMG occurs after the vibration stimulation. Abnormal gamma motor neurons are believed to be involved, and the abnormality results from reduced afferent nerve activity of

All in all, clinical application of vibration stimulation on patients with musculoskeletal

This section provides an overview of the effects of inhibition and facilitation by physical stimuli on skeletal muscle of healthy subjects. We shall then consider the current state surrounding

A decreased H/M ratio was observed by air pressure in the splint on triceps surae muscle of the lower limb (Robichaud et al., 1992) and radiocarpal flexor muscle of the upper limb

Pressure stimulation causes a decrease in blood flow, leads to the state of lack of oxygen, and adversely affects the site of compression of the cell, tissue, or organ. What then would be an appropriate duration and compression strength to apply without bringing on undesirable effects? In a study of healthy Japanese youths, the condition of 5 minutes at 50 mmHg was recommended as appropriate (Miura et al., 2011). A pressure of up to 50 mmHg did not result in any statistically significant differences in blood flow compared with no-addition pressure stimuli. But at this time the excitability of soleus muscle motor neurons was inhibited in the

**3. Inhibitory and facilitative effects of muscle tone in normal healthy**

disorders awaits further trials because there remain some unsettled issues.

spastic muscle in stroke patients will be revealed in the near future.

*of vibration stimulation*

the joints.

**subjects**

spinal cord.

the patient have efficient training.

the physical stimulus in the field.

(Agostinucci et al., 2006) both in healthy subjects.

**3.1. Pressure stimulation**

It may be possible to facilitate the activity of the muscle that is important to knee joint extension, namely vastus lateralis muscle, when vibration stimulation decreases its activity. In fact, we have confirmed that, when vastus lateralis muscle was stimulated by vibration, the reduction in the amount of muscle activity was observed in only vastus lateralis muscle among quadri‐ ceps femoris muscles (Table 2).

There may be a possibility of enhancing the activity of inner muscles, which were long assumed to be unsusceptible to strengthening, provided that you can selectively suppress just those muscles you want to suppress. It is hoped that our future studies will clarify this issue as well.


**Table 1.** Muscle force of quadriceps femoris muscle before and after vibration stimulation (%BW).


\*p<0.05: pre-vibration vs post-vibration

Mean±standard deviation

**Table 2.** Muscle activity of quadriceps femoris muscle before and after vibration stimulation (%iEMG).

### **2.4. Previous studies by other authors**

#### *2.4.1. Spasticity of upper limb in stroke patients is suppressed by 5 to 10 minutes of vibration stimulation*

If vibration stimulation of about 5 to 10 minutes is applied on the spastic muscle of a stroke patient's upper limb, the following will be observed: a decrease in the H/M ratio indicative of the excitability level of anterior horn cells in the spinal cord; improvement of motor function and of Modified Ashworth Scale indicative of the degree of spasticity; and improvement of Functional Ability Scale using Wolf Motor Function Test. In some treatment cases, an imme‐ diate effect was recorded after the intervention.

The nervous system of a spastic stroke patient may be restructured and/or strengthened by adjusting the level of CNS excitability using a vibration stimulus in combination with training on the nervous system. It is anticipated that further effects that vibration stimulation has on spastic muscle in stroke patients will be revealed in the near future.
