Surface electromyography (SEMG)

Report

Prepared by

Dr. Kathy Ermler

Dr. Mike Butler

Dr. Paul Luebbers

For

Trikke Company

August 24, 2007

Trikke EMG Report

Testing Protocol

All testing was done with a Noraxon Myotrace 400. The Myotrace 400 is a portable surface

electromyography (SEMG), which is used to detect the electric activity of a muscle.

Electrodes were placed on the skin directly on the muscle belly and parallel to the grain of

the muscle fibers.

Summary of Findings

It must be stated that the summary that follows is not representative of extensive SEMG

testing, but represents the initial findings of SEMG testing on Trikke riding. At this point

there are more questions that have been raised than specific answers with regards to

muscle activity and Trikke riding. The general findings include:

1. The parts of the body that are most used for the following types of riding:

a. Arms Easy – Arms, shoulders, upper leg and lower leg. The Triceps or the

back of the upper arm is particularly active during arms easy. This type of

riding would be characteristic of a beginning rider. In this particular riding

style, there was a difference between John and Gildo in the use of various

muscles. John used his quadriceps (VLO and Rectus Femoris) and Hamstrings

(Biceps Femoris) more than Gildo. Gildo appeared to use his lower legs

(Gastracnemius (lateral/medial) muscles more than the his quadriceps or

hamstrings.

b. Arms Hard – The arms hard style appears to be a good overall body workout

for many muscles in the body. Arms, shoulders, chest, abdomen, buttocks,

upper leg, lower leg. The primary muscular activity for Gildo was in the arms,

shoulders and lower leg. The primary muscular activity for John was in arms,

upper leg and back.

c. Speed – The speed style is very similar to the arms hard style with one

exception. In the speed style, both John and Gildo use more upper leg

(quadriceps and hamstrings) than on the arms hard. This style provides a

good overall body workout for all muscles of the body.

d. Squat – The squat style is more of an interval style that a riding style. In

other words, a person would not set out to ride long distances or for long

amounts of time using a squatting technique. However, the rider may use

this technique in short bursts during the ride. The primary muscle area that

is activity is the quadriceps. This style could be used to put additional stress

on the quadriceps during a ride.

e. Uphill and Downhill – Not enough data were collected to draw any conclusions

about uphill and downhill riding. However, it appears that on the data that

were collected, riding uphill greatly enhances the activity of the muscles.

2. One area of the body that does not seemed to be particularly active during any of

the types of rides is the abdominal area. Trikke riding may not provide sufficient

work to stress the abdominal muscles. Additional exercises outside of Trikke riding

may need to be done to develop the abdominal area.

3. Cardiovascular benefits –heart rate monitors were used by John and Gildo only one

time. Riding the Trikke put both John and Gildo into their target heart rate zones.

This is one area that needs to be pursued further.

Future questions

1. How do the SEMG patterns seen when riding a Trikke compare to a person’s

Maximum voluntary contractions?

2. How do the SEMG patterns seen when riding a Trikke compare to the same person

running, walking or biking?

3. Is the Trikke effective in improving cardiorespiratory fitness?

4. How do the SEMG patterns of a beginning Trikke rider different from an advanced or

intermediate rider?

5. Are the differences noted between Gildo and John characteristic of an efficient vs an

inefficient rider?

Muscles by Style and Rider

Please note the following charts show muscle activity during particular styles of riding. This

data must be interpreted with some caution since the muscle activity depicted in the style

charts is not necessarily comparable. The bars in the charts indicate the actual microvolts of

electrical activity that were detected with the surface EMG equipment. However, a certain

level of activity in one muscle only shows the degree to which that one muscle was active.

For instance, Gildo shows over 80 microvolts (mv) of activity in his triceps during the arms

easy style. Also, Gildo shows about 30 mv of activity in his brachioradials during the same

ride. One may be tempted to conclude that the triceps were over twice as active as the

brachioradials while riding in this style since the activity of the triceps at 80 mv is over twice

that of the brachioradials at 30 mv. However, these numbers share no common reference.

It is possible that the 80 mv in the triceps is less than half of the activity possible in the

triceps and that the 30 mv in the brachioradialis indicates a near maximal effort for that

muscle. For this reason, strong conclusions based on comparing these numbers should be

avoided. This problem can be resolved in future research by using percentages of maximal

effort or maximum voluntary contraction (MVC) (a relative measure), which will allow direct

comparisons.

On the other hand, it is entirely reasonable to compare the activity of a single muscle or

muscle group across the various styles to show which styles evoke the greatest activity in a

particular muscle or muscle group. This is presented after a consideration of the muscle

activity within each of the selected riding styles.

Arms Easy

In the arms easy style, the following muscles were used for John and for Gildo

Ranking (Top 5 muscles

used)

Gildo John

1 Triceps Vastus lateralis (Quadriceps)

Lateral Gastrocnemius Triceps

Medial Gastrocnemius Biceps Femoris

Brachioradialis Serratus Anterior

5 Vastus lateralis (Quadriceps) Middle Trapeziod

Arms Hard

In the arms hard style, the following muscles were used for John and for Gildo

Ranking (Top 5 muscles

used)

Gildo John

1 Triceps Vastus lateralis (Quadriceps)

Deltoid Triceps

Brachioradialis Middle Trapezoid

Medial Gastrocnemius Deltoid

5 Vastus lateralis (Quadriceps) Rectus Femoris

Speed

In the speed style, the following muscles were used for John and for Gildo

Ranking (Top 5 muscles

used)

Gildo John

1 Triceps Vastus lateralis (Quadriceps)

Rectus Femoris Rectus Femoris

Brachioradialis Triceps

Serratus Anterio Serratus Anterior

5 Lateral Gastrocnemius Deltoid

Squat

In the squat style, the following muscles were used for John and for Gildo

Ranking (Top 5 muscles

used)

Gildo John

1 Vastus lateralis (Quadriceps) Vastus lateralis (Quadriceps)

Rectus Femoris Rectus Femoris

Triceps Serratus Anterior

Biceps Femoris Middle Trapezoid

5 Brachioradialis Biceps Femoris

Uphill

In the Uphill style, the following muscles were used for John and for Gildo

Ranking (Top 5 muscles

used)

John

1 Rectus Femoris

Triceps

Medial Gastrocnemius

Brachioradialis

5 Deltoid

EMG Results by Individual Muscles

Arms

Muscles tested in upper and lower arms include Biceps, Triceps and Brachioradialis

Biceps

The biceps brachii is an elbow flexor and is more

efficient with this motion when the radioulnar joint

(forearm) is supinated. Typically, when riding a

Trikke, the forarms are pronated, so this position

would reduce the amount of biceps participation in

the action. In examining the SEMG patterns for

Biceps, the biceps are used primarily in advanced

types of riding (e.g., speed, punching, pulling

squatting). There was no data for John on the

biceps.

Biceps Brachi

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Triceps

The primary function of the Lateral Triceps is elbow

extension. Based on the SMEG patterns, it appears

that the Triceps are the primary muscles to be

activated in various types of riding, except for

pulling, punching and deep carving. Both John and

Gildo have similar activation patterns for the

Triceps except for uphill. It appears John is using

his Tricep muscles far more on uphills than Gildo.

Gildo uses his Triceps more on almost every type

of riding other than uphill. This may be one

significant difference between efficient and

inefficient Trikke riders. Although without further

SEMG testing, this conclusion is not based on

sufficient data.

Lat Triceps

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Brachioradialis

The brachioradialis is an elbow flexor. When the

forearm is pronated, the brachioradialis is more active

during elbow flexion since the biceps muscle is in a

mechanical disadvantage. Trikke riding requires the

rider to assume and maintain a pronated position.

Based on the SEMG patterns of John and Gildo, it

appears there is a difference in the use of the

brachioradialis muscles between an efficient and

inefficient rider. The lower arms are not used to any

significant degree in any type of riding except uphill

riding for John but are used relatively consistently

across types of ride for Gildo.

Brachiorad

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Brachioradialis

Chest Area

Pectoralis Major

The primary function of the Pectoralis Major is to move the

upper arm across the body (transverse flexion). Based on

the SEMG, a relatively consistent pattern of use between

John and Gildo can be seen. It appears that the pectoralis

major is activated but at a very low level and does not

seem to contribute to the motion of the trikke except when

riding up hill or uphill hard.

Pect Major

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Pectoralis

Major

Serratus Anterior

The Serratus Anterior draws the scapula forward, abducts

the scapula and stabilizes the vertebral border of the

scapula to the rib cage. Based on the SEMG pattern, it

appears that the Serratus Anterior is moderately active in

all forms of riding for both John and Gildo.

Serr Ant

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Shoulders

Anterior Deltoid

The function of the Deltoid muscle is essentially to move

the arm away from the body. The Anterior head raises

the arm away to the front of the body. The Anterior

Deltoid is active in all types of Trikke riding for both John

and Gildo; particularly arms hard and uphill riding.

Anterior Deltoid

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Anterior

Deltoid

Abdominal Area

Rectus Abdominus Upper and Lower

The Rectus Abdominus muscle is really one long muscle that runs

from the sternum to the pubic bone. It is commonly known as the

"six-pack" muscle of the abdominal area. The upper Rectus

Abdominus Upper (URA) muscle runs from the sternum to the

navel. The Rectus Abdominus Lower (LRA) muscle runs from the

navel to the pubic bone. The Rectus Abdominus muscle assists in

the flexion of the spine (bringing the rib cage closer to the pelvis

or pelvis closer to the rib cage).

In most of the riding styles, there is very little activity in either the

URA or the LRA. The greatest activity in the Rectus Abdominus

muscle is found in styles that include off Trikke work (e.g., skip jump). The increase in

muscle activation in the Rectus Abdominus muscle may be a function of a running motion

rather than the action of riding a Trikke. Gildo was not tested on the URA or LRA for uphill.

Rect Abd Upper

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Rect Abd Lower

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External Obliques

The External Obliques run diagonally

along the trunk. These muscles work to

rotate the torso and stabilize the

abdomen. According to the SEMG

pattern, very little activity is occurring in

the External Obliques in most riding

styles. This seems very surprising

considering the rotational aspect of the

Trikke motion.

Ext. Obliques

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External Obliques

Back

Middle Trapezius

The Trapezius (trap) muscle is a long, trapezoid-

shaped muscle that runs down the upper section

of the spinal cord, originating at the base of the

skull and attaching down in the middle to lower

back. The Trapezius muscle permits scapular

elevation (shrugging up), scapular adduction

(drawing the shoulder blades together) and

scapular depression (pulling the shoulder blades

down). Based on the SEMG, John appears to use

the Trapezius mucles significantly more than

Gildo in all types of riding. This difference could

again be the difference between an efficient and

an inefficient rider or differences in riding styles between these two riders.

Mid Trap

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Middle

Trapezius

Latissimus Dorsi

Latissimus Dorsi muscles are the largest muscles of

the back and are large, fan-shaped muscles located in

the middle of the back. The Latissiumus Dorsi

extends, adducts and medially rotates arm. It is

difficult to draw any conclusions between the two

individuals since no data was taken on John for arms

easy, hard, speed and uphill. However, based on very

limited data, it appears that the Latissimus Dorsi is used when riding a Trikke.

Lat Dorsi

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Latissimus

Dorsi

Erector spinae

The Erector spinae muscles run directly down the vertebrae and act to laterally flex and

extend the spine.

ES

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Buttock Gluteus max

The Gluteus Maximus muscle acts to externally rotate and

extend the hip. This muscle is the strongest muscle in the

human body. No activity was noticed in this muscle in arms

easy, arms hard and very little activity was noted in this

muscle in the squat or speed riding. This result is mostly

likely attributed to the functioning of the SEMG machine

and not a result of inactivity of the Gluteus Maximus

muscle; although this is to be determined with further

testing. This muscle acts to straighten the leg at the hip

when someone is walking or running. When a person is

Trikking, there is very little opportunity to flex and extend

at the hip during the ride.

Please note that “the equipment was not working to read properly on the gluteus muscles, as

riding has proven that these muscles are also activated while riding, though in this test the

equipment did not pick it up.”

Glut Max

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Gluteus Medius

The Gluteus Medius muscle lies partially under the Gluteus Maximus muscle and acts to

abduct the hip and rotate the leg medially. In all types of Trikke riding, this muscle is

moderately active. The rocking motion of the Trikke would uses abduction at the hip. Both

John and Gildo use this muscle relatively similarly and across all types of rides.

Glut Med

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Back of the Upper Legs - Hamstrings

Biceps Femoris

The Biceps Femoris muscles are located on the back of

upper legs. The Biceps Femoris flexes the knee, rotates

the tibia laterally; long head also extends the hip joint.

The Biceps Femoris were activated during all types of

riding for both Gildo and John. The greatest activation

of the Biceps Femoris occurred during the ski jump and

deep carving. Uphill and downhill were not tested.

Biceps Fem

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Semitendinous

The Semitendinous is located on the back of the upper leg. It extends the thigh and flexes

the knee, and also rotates the tibia medially, especially when the knee is flexed. Similar to

the Biceps Femoris, this Semitendinous muscle is activated during all types of riding for

both Gildo and John. The greatest activation of this muscle occurred during the ski jump

and deep carving.

Semi Tend

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Front of Upper Legs – Quadriceps

Rectus Femoris

The Rectus Femoris is one of four

muscles that make up the quadriceps

muscles in the upper leg. It acts to

extend the knee. This muscle is

activated in most types of Trikke

riding, but are highly active when

riding uphill.

Rect Fem

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Rectus

Femoris

Vastus Lateralis

The Vastus Lateralis is one of four muscles that make up the

quadriceps muscles in the upper leg. It acts to extend the knee.

This muscle is activated in most types of Trikke riding, but are

highly active when riding in a squat position or riding downhill.

VLO

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Lower Legs – Calf Muscles

Lateral and Medial Gastrocnemious

The Gastrocnemious muscle is located on

the back of the lower leg. It has two heads;

a lateral head and a medial head. Both

muscles act as a very powerful plantar

flexor of the foot; it also aids in flexion of

the knee. It appears that Gildo’s riding style

allows for more activation of the

Gastrocnemious muscle than John’s riding

style. Gildo uses a plantar flexion motion to

move the Trikke, while John remains more

flat footed doing the ride.

Lat Gastroc

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Med Gastroc

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Lateral and

Medial Gatronemious