Beurer EM41: ENGLISH

ENGLISH

Table of Contents

1. Getting to know your machine ............................................................... 17

7. Application ...............................................................................................26

1.1 What is Digital TENS/EMS and what can it do?..................................17

7.1 Advice on application ........................................................................26

1.2 Scope of supply ..................................................................................18

7.2 Procedure for TENS, EMS and MASSAGE programmes 01–10 .......26

7.3 Procedure for TENS/EMS programmes 11– 20 (ind. prog.) ............... 26

2. Important information ............................................................................. 18

7.4 Changes to settings .......................................................................... 27

3. Current parameters ................................................................................20

7.5 Doctor’s Function ..............................................................................27

3.1 Pulse shape ......................................................................................... 20

8. Cleaning and storage ...........................................................................27

3.2 Pulse frequency ...................................................................................20

3.3 Pulse width ..........................................................................................20

9. Disposal .................................................................................................27

3.4 Pulse intensity .....................................................................................20

10. Problems and solutions ........................................................................ 28

3.5 Cycle-controlled pulse parameter variation ........................................20

11. Technical details ...................................................................................28

4. Unit description .......................................................................................21

4.1 Description of components .................................................................21

4.2 Key functions ......................................................................................21

5. Start-up ....................................................................................................21

6. Programme overview .............................................................................. 22

6.1 Basic information ................................................................................22

6.2 TENS programmes .............................................................................. 23

6.3 EMS programmes ...............................................................................24

6.4 MASSAGE programmes ...................................................................... 25

6.5 Information on placing the electrodes ................................................25

16

Dear Customer,

TENS, transcutaneous electrical nerve stimulation, means electrical

stimu lation of nerves through the skin. TENS is recognised as a clinically prov-

Thank you for choosing one of our products. Our name stands for high-quality,

en, effective, non-medication method of treating pain from certain causes. It

thoroughly tested products for the applications in the areas of heat, weight,

is free from side-effects when used properly, and can also thereby be used as

blood pressure, body temperature, pulse, gentle therapy, massage and air.

a simple means of self-treatment. The pain-alleviating or suppressing effect

Please read these instructions for use carefully and keep them for later use, be

is also achieved by preventing pain from being passed on into nerve fibres

sure to make them accessible to other users and observe the information they

(above all through high-frequency pulses) and increasing the secretion of the

contain.

body’s own endorphines which reduce awareness of pain through their effect

on the central nervous system. The method is scientifically underpinned and

Best regards,

medically approved.

Your Beurer Team

Any symptoms indicating TENS application must be clarified with the doctor

1. Getting to know your machine

in charge of your treatment. The latter will also give you information on the

1.1 What is Digital TENS/EMS and what can it do?

respective benefits of TENS self-treatment.

TENS is clinically tested and approved with the following applications:

Digital TENS/EMS belongs to the group of electrical stimulation systems. It

•

Back pain, particularly also lumbar and cervical spine problems

has three basic functions, which can be used in combination:

•

Joint pain (e.g. knee joint, hip joint, shoulder)

1. Electrical stimulation of nerve tracts (TENS).

•

Neuralgia

2. Electrical stimulation of muscle tissue (EMS).

•

Headaches

3. A massage effect generated by electrical signals.

•

Women’s period pains

For this, the device has two independent stimulation channels and four self-

•

Pain after injuries to musculoskeletal system

adhesive electrodes. It has various versatile functions in order to increase

•

Pain with circulatory problems

general wellbeing, alleviate pain, maintain physical fitness, relaxation, revitalise

•

Chronic pain through various causes

muscles and combat fatigue. You can either select these functions from preset

Electrical muscle stimulation (EMS) is a widespread and generally recog-

programmes or determine them yourself according to your requirements.

nised method and has been used for years in sports and rehabilitation medi-

The operating principle of electrical stimulation equipment is based on

cine. In the sports and fitness field, one of the uses of EMS is as a supplement

simulating the body’s own pulses which are transmitted transcutaneously to

to conventional muscle training, in order to increase the efficiency of muscle

nerve or muscle fibres by means of electrodes. The electrodes can thereby

groups and adapt physical proportions to the desired aesthetic results. EMS

be attached to many parts of the body, whereby the electrical stimuli are

application goes in two directions. On the one hand, a targeted strengthening

safe and practically painless. You merely feel a gentle prickling or vibrating in

of musculature can be produced (activating application) and on the other hand

some applications. The electrical pulses transmitted to the tissue affect the

a relaxing, resting effect can also be achieved (relaxing application).

trans mission of stimulation in nerve conductions as well as neural nodes and

Active application includes the following:

muscle groups in the field of application.

•

Muscle training to improve endurance performance and/or

The effect of electrical stimulation is generally only recognisable after regularly

•

Muscle training to support the strengthening of certain muscles or muscle

repeated application. Electrical stimulation does not replace regular exercising

groups in order to achieve desired changes to body proportions.

of the muscle, but is able to reasonably supplement the effect thereof.

17

Relaxing application includes the following:

•

Muscle relaxation in order to loosen up muscular tension

2. Important Information

•

Improving muscular fatigue symptoms

Use of the machine does not replace medical consultation and treat-

•

Accelerating muscle regeneration after high muscular performance (e.g.

ment. In the event of any type of pain or illness, you must therefore

after a marathon).

always first ask your doctor.

Through integrated massage technology, Digital TENS/EMS also offers the

WARNING!

possibility of reducing muscular tension and combating fatigue symptoms

In order to prevent any damage to health, we would urgently

using a programme based on real massage in terms of sensation and effect.

advise against using the Digital TENS/EMS in the following

Using the positioning suggestions and programme charts in this manual, you

cases:

can determine the machine setting fast and easily for the respective applica-

•

With any implanted electrical devices (such as pacemakers)

tion (depending on the region of the body affected) in order to ensure the

•

If there are any metal implants

•

When using an insulin pump

desired effect.

•

In case of high fever (e.g. > 39 °C)

Through the two separately adjustable channels, the Digital TENS/EMS has

•

In case of known or acute cardiac arrhythmias and other disorders in

the advantage of adapting the intensity of the pulses independently of each

stimulus formation and conduction of the heart

other to two parts of the body to be treated, for example in order to cover

•

If suffering from attacks (e.g. epilepsy)

both sides of the body or ensure even stimulation of larger areas of tissue.

•

If pregnant

The individual intensity setting of each channel also allows you to treat two

•

In case of cancer

different parts of the body at the same time, whereby it is possible to save

•

After operations where increased muscle contractions

time compared with individual sequential treatment.

might impair the healing process

•

Never use near the heart. Stimulation electrodes should

1.2 Scope of supply

never be placed anywhere on the front of the thorax

– 1x Digital TENS/EMS machine (incl. belt clip)

(marked by ribs and breastbone), but above all not on the

– 2x connecting cable

two large pectoral muscles. Here it can increase the risk of

– 4x adhesive electrodes (45 x 45 mm)

ventricular fibrillation and lead to cardiac arrest

– 3x AAA batteries

•

On the bony part of the cranium, near the mouth, throat or larynx

– these instructions for use

•

Near the throat / carotid artery

– 1x brief instructions (suggestions on placing electrodes and fields of

•

Near the genitals

application)

•

On acutely or chronically diseased (injured or inflamed) skin (e.g. in the

– 1x storage bag

event of painful and painless inflammation, reddening, skin rashes (e.g.

Subsequent purchase articles

allergies), burns, bruises, swellings, open wounds and wounds in the

process of healing, on operation scars in the process of healing)

Back belt with 4 wear-free water contact electrodes, mat. no. 162.825

•

In environments with high humidity such as in the bathroom or when

8x adhesive electrodes (45 x 45 mm), Art. no. 661.02

having a bath or shower

4x adhesive electrodes (50 x 100 mm), Art. no. 661.01

•

Do not use after consuming alcohol

•

When a high frequency surgical device is connected at the same time

18

Before using the machine, you should consult with the doctor in charge

•

To remove or move the electrodes, first switch off the machine or the ap-

of your treatment in the event of the following:

propriate channel in order to avoid unwanted irritation.

•

Acute diseases, especially if hypertension is suspected or actually exists,

•

Never modify any electrodes (e.g. by cutting). This leads to a higher current

or blood-clotting disorders, tendency to thromboembolic diseases or in

density and can be dangerous (max. recommended output value for

case of malignant new masses

2

electrodes: 9 mA/cm

, an effective current density over 2 mA/cm² requires

•

All skin diseases

greater attention).

•

Chronic pain disorders which have not been clarified, regardless of the

•

Do not use when asleep, when driving a vehicle or at the same time as

region of the body

operating machinery.

•

Diabetes

•

Never use with any activities where an unforeseen reaction (e.g. increased

•

All sensitivity disorders with reduced pain awareness (such as metabolic

muscle contraction despite low intensity) may be dangerous.

disturbances)

•

Make sure that no metallic objects such as belt buckles or necklaces can

•

Medical treatments carried out simultaneously

come in contact with the electrodes during stimulation. If you wear any

•

Complaints arising as a result of the stimulation treatment

jewellery or piercings (e.g. belly piercing) near the application site, you

•

Constant skin irritation as a result of prolonged stimulation at the same

must remove these before using the machine as burning may otherwise

electrode point.

occur at some points.

•

Keep the device away from children to prevent any hazards.

IMPORTANT!

•

Do not confuse the electrode cables and contacts with your headphones

Use the Digital TENS/EMS solely:

or other devices, and do not connect the electrodes to other devices.

•

On humans

•

Do not use this machine at the same time as other equipment which sends

•

For the purpose for which it was developed and in the manner specified in

electrical pulses to your body.

these instructions for use. Any improper use can be hazardous.

•

Do not use it near any highly flammable substances, gases or explosives.

•

For external application.

•

Never use accumulators, always use the same types of battery.

•

With the original accessory parts which are supplied and can be re-ordered,

•

In the initial minutes, carry out the application sitting or lying down in order

otherwise the warranty becomes null and void.

to avoid any unnecessary risk of injury in the rare event of a vagal reaction

PRECAUTIONARY MEASURES:

(feeling of weakness). If you start feeling weak, switch the machine off

immediately and put your legs up (approx. 5–10 minutes).

•

Always remove the electrodes from the skin with a moderate pull in order

•

It is not advisable to apply any enriching creams or ointments to the skin

to avoid injury in the event of highly sensitive skin.

beforehand, as this greatly increases electrode wear or else unpleasant

•

Keep the machine away from heat sources and never use it near (~1 m)

current spikes may occur here.

short-wave or microwave equipment (e.g. mobile phones), as this may

lead to unpleasant current spikes.

Damage:

•

Do not expose the machine to direct sunlight or high temperatures.

•

If the machine is damaged, do not use it if you are in any doubt but rather

•

Protect the machine from dust, dirt and humidity. Never submerge the

contact your dealer or the customer service address indicated.

device in water or other liquids.

•

Check the device at regular intervals for signs of wear or damage. If you

•

The machine is suitable for private use.

find any such signs or if the device was used improperly, you must bring it

•

For reasons of hygiene, the electrodes should only be used on one person.

to the manufacturer or dealer before it is used again.

•

If the machine is not functioning properly, or if you start feeling unwell or

•

Switch off the device immediately if it is defective or if is not working properly.

there is any pain, stop the application immediately.

19

•

Do not, under any circumstances, attempt to open or repair the machine

while fast-response fibres only respond to frequencies over approx. 35 Hz.

yourself! Only have repairs carried out by the customer service department

With pulses of approx. 45–70 Hz, there is permanent tension in the muscle

or an authorized dealer. If these instructions are not heeded, the warranty

combined with premature muscle fatigue. Higher pulse frequencies can

becomes null and void.

therefore preferably be used for elasticity and maximum strength training.

•

The manufacturer assumes no liability for damage caused through im-

3.3 Pulse width

proper or wrong use.

Pulse width is used to indicate the duration of an indi-

Pulse width

Information on ESD (Electrostatic Discharge)

vidual pulse in microseconds. Pulse width also determines

Please note that jacks marked with the ESD warning label must not

the pene tration depth of the current whereby in general,

be touched.

the following applies: a greater muscle mass requires a

ESD protective measures:

greater pulse width.

– Do not touch plugs/jacks marked with the ESD warning label with fingers!

3.4 Pulse intensity

– Do not touch plugs/jacks marked with the ESD warning label with hand-

held tools!

Setting the degree of intensity is individually dependent

on the subjective feeling of each individual user and is

Further explanations on the ESD warning label, as well as possible training

determined by a number of parameters such as application

courses and their contents, are available on request from the customer

site, skin circulation, skin thickness as well as quality of elec-

service department.

trode contact. The actual setting should be effective but should never produce

3. Current parameters

any unpleasant sensations such as pain at the site of application. While a slight

tingling sensation indicates sufficient stimulation energy, any setting which leads

Electrical stimulation machines operate with the following current settings,

to pain must be avoided.

which will alter the stimulation effect depending on the setting.

With prolonged application, readjustment may be necessary due to time

3.1 Pulse shape

adjustment processes at the site of application.

This describes the time function of the excitation current.

monophase pulses

3.5 Cycle-controlled pulse parameter variation

whereby monophase pulse trains are differentiated from

pulse

intensity

In many cases it is necessary to cover the entirety of tissue structures at the

biphase. In monophase pulse trains the current flows in

time

site of application by using several pulse parameters. With the Digital TENS/

one direction, in biphase pulse trains the excitation current

biphase pulses

EMS unit, this is done by the existing programmes automatically making a

changes direction.

cyclical pulse parameter change. This also prevents individual muscle groups

In the Digital TENS/EMS unit, there are only biphase pulse

at the site of application from getting tired.

trains, as they reduce the strain on the muscle, leading to

With the Digital TENS/EMS unit there are useful presettings for current

less muscle fatigue as well as safer application.

para meters. During the application, however, you do have the possibility of

3.2 Pulse frequency

changing pulse intensity at any time and, with individual programmes, you

Frequency indicates the number of individual pulses per

periodic

time

can also alter pulse frequency beforehand in order implement the application

second, and is indicated in Hz (Hertz). It can be calculated

which is the most comfortable or promises the most success for you.

by working out the inverse value of the periodic time. The

respective frequency determines which types of muscle fibre preferably react.

Slow-response fibres tend to react to lower pulse frequencies up to 15 Hz,

20

4. Unit description

A

(2) The DOWN key  is used to reduce pulse intensity for both channels

during stimulation.

4.1 Description of components

Display (main menu):

MENU

E

A Pulse intensity

B

(1) Navigation between the submenus TENS, EMS and MASSAGE.

B Programme/cycle numbers

(2) Return to (A) programme selection window or (B) main menu.

C

F

C Frequency (Hz)

ENTER

D

G

D Low battery

(1) Menu selection.

E TENS/EMS/MASSAGE menus

(2)

To confirm a selection made with UP/DOWN, apart from channel intensity.

F Timer function (residual time indicator)

e

e

CH1+, CH1-, CH2+, CH2-

G Operating status display

Setting pulse intensity.

Keys:

a  UP and  DOWN selection keys

5. Start-up

a

c

b ENTER confirmation key

1. Remove the belt clip from the machine, if attached.

b

d

c ON/OFF key

2. Press on the battery cover at the back of the machine and

d MENU key

push it to the side.

e CH1+, CH1-, CH2+, CH2- intensity keys

3. Insert three AAA 1.5 V alkaline batteries. Make absolutely

sure that you insert the batteries with the correct polarity

Accessories:

as marked.

Fig. 1

•

2x connection cable

4. Replace the battery cover carefully (Fig. 1).

•

4x adhesive electrodes

5. Attach the connecting cable to the electrodes (Fig. 2).

(45 x 45 mm)

i

Note: The electrodes have a clip fastener to ensure

•

1x belt clip

easy connection.

4.2 Key functions

Every time a key is pressed, this is acknowledged by a signal tone in order to

Fig. 2

ensure that any unintentional pressing of a key is detected. This signal tone

cannot be switched off.

ON/OFF

(1)

Hit briefly to switch on the machine. If the key is held down for 10 seconds

when switching on, the unit automatically switches off again.

(2) Press once to interrupt stimulation treatment = pause mode.

(3) Hold ON/OFF key down (approx. 3 seconds) to switch off the machine.

 and 

(1) Select between (A) treatment programme, (B) frequency and (C) treatment

time.

21

6. Programme overview

6.1 Basic information

The Digital TENS/EMS unit has a total 50 programmes:

•

20 TENS programmes

•

20 EMS programmes

•

10 MASSAGE programmes

With all programmes, you can set the length of application and (for each of

the two channels) pulse intensity separately.

Besides this, with TENS and EMS programmes 11– 20, you can also change

the pulse frequency of the individual cycles in order to adapt the stimulation

effect to the structure of the site of application.

Cycles are the different sequences making up the programmes. They auto-

matically run one after the other and increase the efficacy of stimulation on

different types of muscle fibre and combat premature muscle fatigue.

You will find the standard stimulation parameter settings and information on

placing the electrodes in the following programme charts for TENS, EMS and

MASSAGE.

22

6.2 TENS programmes

Prog.

Reasonable areas of

Possible

Cycle 1 Cycle 2 Cycle 3 Cycle 4

No.

application

electrode

Cycle 5 Cycle 6 Cycle 7 Cycle 8

Indications

position

Width

Fre-

On

Off

Width

Fre-

On

Off

Width

Fre-

On

Off

Width

Fre-

On

Off

(µs)

quen-

Time

Time

(µs)

quen-

Time

Time

(µs)

quen-

Time

Time

(µs)

quen-

Time

Time

cy (Hz)

(sec.)

(sec.)

cy (Hz)

(sec.)

(sec.)

cy (Hz)

(sec.)

(sec.)

cy (Hz)

(sec.)

(sec.)

1 + 11 Neck pain, tension

01, 02, 13 250 4 30 0 250 4 30 0 250 5 30 0 250 5 30 0

headache

250 6 20 0 250 6 20 0 250 8 30 0 250 8 30 0

2 + 12 Back pain 03, 04, 05,

250 6 30 0 250 6 30 0 250 8 20 0 250 8 20 0

06, 15, 23

250 10 20 0 250 10 20 0

3 + 13 Shoulder pain 07, 14 250 2 10 0 250 4 8 0 250 6 6 0

4 + 14 Pain as a result of

See note 250 60 20 0 250 70 20 0 250 80 30 0 250 80 30 0

rheumatoid arthritis

5 + 15 Lumbar pain 22 250 80 20 0 250 80 20 0 250 75 4 0 250 10 20 0

250 70 4 0 250 65 4 0

6 + 16 Menstrual pain 08 250 40 30 0 250 45 30 0 250 55 30 0 250 60 30 0

7 + 17 Pain programme I See note 250 4 30 0 250 4 20 0 250 6 30 0 250 6 20 0

250 8 30 0 250 8 20 0 250 10 30 0 250 10 20 0

8 + 18 Knee pain

09, 10 250 40 5 0 250 6 10 0 250 50 5 0

Ankle joint pain,

capsular injuries

9 + 19

Pain programme II See note 250 75 0,25 0,25 250 2 0,5 0

(Burst)

10 + 20

Pain programme III See note 250 100 0,25 0,25

(Burst)

On-Time (sec.) = Cycle switch-on time in seconds (contraction) – Off-Time (sec.) = Cycle switch-off time in seconds (relaxation)

Note: Electrode position is supposed to surround the painful area. With painful muscle groups, the electrodes are grouped round the muscle affected. In case of joint pain, the joint

on the front/rear side of the joint and, if electrode distances permit, on the right and left sides of the joint, should be surrounded with electrodes.

Minimal electrode distance should not be less than 5 cm and not exceed 15 cm. See figure no. 9 an 10 for knee and ankle joint.

Burst programmes are suitable for all sites which should be treated with an alternating signal pattern (to ensure minimum habituation).

23

6.3 EMS programmes

Prog.

Reasonable areas of

Possible

Cycle 1 Cycle 2 Cycle 3 Cycle 4

No.

application

electrode

Cycle 5 Cycle 6 Cycle 7 Cycle 8

Indications

position

Width

Fre-

On

Off

Width

Fre-

On

Off

Width

Fre-

On

Off

Width

Fre-

On

Off

(µs)

quen-

Time

Time

(µs)

quen-

Time

Time

(µs)

quen-

Time

Time

(µs)

quen-

Time

Time

cy (Hz)

(sec.)

(sec.)

cy (Hz)

(sec.)

(sec.)

cy (Hz)

(sec.)

(sec.)

cy (Hz)

(sec.)

(sec.)

1 + 11 Shoulder muscles 07, 14 250 30 5 1 250 10 15 1 250 50 5 1

2 + 12 Middle and lower trapezius

01, 02, 03,

250 4 30 1 250 4 20 1 250 5 30 1 250 5 20 1

muscle, lattisimus dorsi

04, 05, 12,

250 6 30 1 250 6 20 1

muscle, neck muscles

15

3 + 13 Back musculature near

03, 06, 22,

250 2 10 1 250 4 10 1 250 6 10 1

spinal column, Prog. I

23

4 + 14 Front and back upper arm

16, 17, 18,

250 4 30 1 250 4 30 1 250 4 30 1 250 5 30 1

musculature (including

19

biceps), front and back

250 5 30 1

lower arm musculature

5 + 15 Straight and transverse

11, 20, 21 250 6 15 1 250 8 15 1 250 10 15 1

abdominal musculature

6 + 16 Back musculature near

03, 06, 22,

250 2 20 1 250 2 20 1 250 1 30 1 250 1 30 1

spinal column, Prog. II

23

7 + 17 Back musculature near

03, 06, 22,

250 4 30 1 250 4 20 1 250 6 30 1 250 6 20 1

spinal column, Prog. III

23

250 8 30 1 250 8 20 1

8 + 18 Posterior musculature 24 250 20 5 1 250 6 5 1 250 30 5 1

9 + 19 Front and back upper thigh

25, 26 250 20 5 1 250 6 8 1 250 25 5 1

musculature

10 + 20 Front and back lower thigh

27, 28 250 25 5 1 250 6 8 1 250 35 5 1

musculature

On-Time (sec.) = Cycle switch-on time in seconds (contraction) – Off-Time (sec.) = Cycle switch-off time in seconds (relaxation)

24

6.4 MASSAGE programmes

but stimulation is weaker. To increase stimulation, pulse intensity must then

be increased.

Prog. no. Massage form

The following guideline holds when selecting electrode distances:

1 Tap and grasp massage

•

most reasonable distance: approx. 5 –15 cm

•

below 5 cm, it is mainly surface structures which are strongly stimulated

2 Knead and grasp massage

•

over 15 cm, large-area and deep structures are stimulated very weakly

3 Tap massage

Electrode relationship to muscle fibre orientation

4 Side of hand/pressing massage

Choice of current flow direction must be adapted to the muscle fibre orien-

5 Side of hand/pressing massage

tation according to the desired muscle layer. If surface muscles are to be

6 Vibratory massage

reached, the electrodes must be placed parallel to the fibre orientation (P. 2,

Fig. 16; 1A-1B/2A-2B). If deep tissue layers are to be reached, the electrodes

7 Tap massage (switch between electrodes)

must be placed crosswise to the fibre orientation (P. 2, Fig. 16; 1A-2A/1B-

8 Massage jet (switch between electrodes)

2B). The latter arrangement can, for example, be achieved via the cross

9 Pressure massage jet (switch between electrodes)

electrode arrangement, such as P. 2, Fig. 16; 1A-2B/2A-1B.

10 Combination programme (switch between electrodes)

Channel allocation:

Channel 1 (CH1): connection left, intensity controller rocker switch left, pulse

Electrodes must be placed so that they surround the muscle segments in

intensity display left (CH1).

question. For optimal effect, electrode distance must not be greater than

Channel 2 (CH2): connection right, intensity controller rocker switch right,

approx. 15 cm.

pulse intensity display right (CH2).

The electrodes should not be applied to the anterior wall of the

i

In the treatment of pain (TENS) using the Digital TENS/EMS machine

thorax, i.e. never massage the left or right large pectoral muscle.

with its 2 separately controllable channels and in each case 2 adhesive elec-

trodes, it is advisable to either position the electrodes of one channel so that

6.5 Information on placing the electrodes

the pain spot lies between the electrodes or else you position one electrode

For the desired success of any stimulation application, it is important that

directly on the pain spot and the other at least 2 – 3 cm away.

electrodes are placed sensibly.

The electrodes of the second channel can be used to treat other pain spots

We advise you to coordinate with your doctor regarding the best electrode

simultaneously or else, however, together with the electrodes of the first

positions for your intended field of application.

channel, to surround the pain area (opposite). A cross arrangement is again

The electrode positions suggested inside the cover (Figs. 1– 28) serve as a

advisable here.

guide. The following applies when choosing electrode positions:

i

Massage function tip: always use all 4 electrodes to ensure optimal

Electrode distance

treatment.

The greater the electrode distance which is selected, the greater will be the

i

In order to extend the durability of the electrodes, use them on clean skin

volume of tissue that is stimulated. This applies to the area and the depth of

which is as free as possible from hair and grease. If necessary, clean the skin

the tissue volume. At the same time, however, the strength of tissue stimula-

with water before application and remove the hair.

tion decreases as the electrode distance becomes greater, which means

that, if a greater electrode distance is chosen, a greater volume is stimulated,

25