Muscular Activity inMaximum Voluntary Contraction of M.Quadriceps Femoris～Testing with Mechanical Vibration (Mechanomyogram: MMG)～
1,2 Toshifumi Dakeshita, 1Hiroya Kudo, 1Koichi Wakimoto, 1Yoshihiro Uchida,1Atsuo Kato,
2Akira Kubo, 3Kazuyoshi Sakamoto
1 Seisen Clinic of Orthopedics, Shizuoka, Japan

Email: dakeshita@seisen.info
2 International University of Health and Welfare, Graduate school
3 Center of Promotion of Alliances with Region, Industry and Government, The University of Electro-Communications, Tokyo, Japan

Background & Introduction

Therapeutic exercise ＝Muscle strength assessment ⇒ exercise prescription

Physiological data in muscle contraction includes action potential or electromyogram (EMG) and mechanomyogram（MMG）,where EMG and MMG are the electric vibration before muscular contraction and the mechanical vibration after muscular
contraction, respectively. Many researchers had reported correlation between action potential and muscle strength, but not
between MMG and muscle strength.

Aim
How to move the Quadriceps Femoris in muscle contruction?
What is the relationship between muscle strength and MMG?
Our research focused on MMG or mechanical vibrations in muscle construction.

Material＆Method
15 men13 womenaverage age 28.9±7.7

Both MMG and muscular strength were measured concurrently
at six points:②①CCI 3D accelerometer

BIODEX System 3Analysis

Respective two places on three muscles of vastus medialis, rectus femoris,
and vastus lateralis, where two places were taken by 5 cm and 10 cm fromthe upper edge of patella.

The power spectrum was calculated by auto-regression (AR) model with four degrees. Total power (TP) was determined bymultiplying sum of power spectrum within the specified frequency range by fundamental frequency. Simple correlation
coefficient was used to find correlation between MMG and muscle strengthResultY(G2)8060(G2)②①8060XZ

TP 4020TP400X

YZ

3D accelerometer20

r＝0.4425

1800

The maximum mechanical vibrations
were obtained in the horizontal direction.

VM1

VM2

RF1

RF2

VL1

VL2

Position

The maximum TP in MMG was obtained atthe point in the vastus medialis muscle
located approximately 5 cm from the upperedge of the patella.

Conclusion

140Muscle
strength100(G2)The significant positive correlation was
found between MMG and muscle
strength.

60
50100

150200MMG

Andriacchi (1984) showed that in knee extension in isometric contraction, the maximum action potential was obtained in thevastus medialis muscle. Likewise, the maximum MMG was obtained there in our research. This demonstrates that knee joint
extension correlates with the vastus medialis muscle. In addition, the maximum MMG was obtained in the horizontal direction
rather than the front/back or vertical direction. That was probably because amplitude was more limited in the front/back orvertical direction due to the tendon or skin under tension caused by the fully stretched anterior femur. Many things are still
unknown regarding muscle contraction when full muscular strength is delivered. However, the findings from our research maylead to the discovery of new muscle functions. In addition, the significant positive correlation between MMG and muscularstrength means that MMG may become new indicator to test isometric muscular strength.