p3 - ergo - biomechanics

7/30/2019 P3 - Ergo - Biomechanics

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(www.cdc.gov/niosh)

The two most prevalent m

problems are :

(fin

wrists, arms, and should


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Biomekanika adalah ilmu pengetahuan yang mempelajari interaksi

antara pekerja dengan mesin, material dan peralatan dengan tujua

meminimumkan keluhan pada sistem kerangka otot agar produktiv

dapat meningkat.

Pendekatan biomekanika tubuh manusia sebagai suatu sistem

terdiri dari elemen-elemen yang saling berkait dan terhubung satu

lain, melalui sendi-sendi dan jaringan otot yang ada.


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is a science concerned witmechanical behavior of musculoskeletal system and com

tissues when physical work is performed (Chaffin et.al, 19

Biomechanics analyzes the humanthat obeys laws of physics (Wickens et


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Static stre

voluntary

exertion le

Each lasts

with 30 to

provided b


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Dynamics strength data can vary considerably

depending on the dynamic of the task and the way

which the subjects perform it.


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TULANG (BONES)

investigasi padaL5/S1.

SAMBUNGAN (JOINTS) aplikasi teori

fisika (beban, massa, gaya, momen) pada

tubuh manusia.

OTOT (MUSCLE) aerobic & anaerobic

metabolism.


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206 bones in a human body Formed from the rigid skeletal structure

Function :

supportive body : long bones of the upper and lower

extremities protective body : skull (protects brain), rib cage (shields the

lungs and heart)


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Dalam banyak kegiatan

penanganan material seperti

mengangkat, membawa,

mendorong dan menarik,

gaya-gaya yang signifikan

terjadi pada tulang belakang

bagian bawah yaitu pada

, lokasi dimana sering

terjadi cedera punggung.


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Tendons

Dense, fibrous Attach muscle to

bones

Transmit the forces

exerted by muscles

Ligaments

Dense, fibrous Connect the

articular

extremities of

bones

Help stabilize thearticulations of

bones at joints

Cartilage

Translucent elastictissue

On some articularbony surfaces, ex :

nose, ear

Fascia

Coverstructsepara

from e


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Didalam melakukan analisa biomekanik, tubuh manusia dipandang sebag

sistem yang terdiri dari link(penghubung) danjoint(sambungan).

Menurut Ghaffin & Anderson (1984), tubuh manusia terdiri dari enam lin

Link lengan bawah yang dibatasi joint pergelangan tangan dan siku.

Link lengan atas yang dibatasi joint siku dan bahu.

Link punggung yang dibatasi joint bahu dan pinggul.

Link paha yang dibatasi joint pinggul dan lutut.

Link betis yang dibatasi joint lutut dan mata kaki.

Link kaki yang dibatasi joint mata kaki dan telapak kaki.


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Synovial joints : no tissue

exists between the highly

lubricated joint surfaces.

Fibrous joints : connecting

the bones of the skull

through fibrous tissues.

Cartilaginou

bridging verte

and inverteb


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About 400 muscles in a human body, which make up about 40%-5

body weight.

Muscles consume almost 50% of the bodys metabolism.

Muscles also supplies the energy for maintaining body posture, p

body motion, and generating heat/body temperature.

Muscles with larger cross-sections are able to exert larger force


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Concentric / isotonic : muscle while contracting and prod

constant internal muscle force.

Example : arm flexor muscle when object is lifted upward

Eccentric : muscle while contracting, which occurs when

force is greater than the internal muscle force.

Example : a person picks up a heavy object and unable to hold it in the desir

Isometric : the muscle length remains during the contra Example : a person pauses during lifting and holds the object in a static posit

Muscle contraction produces muscle force or tens

transmitted to bones through tendons and is used

body posture and perform physical work.


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Aerobic

Use of O2, efficient, high capacity

Anaerobic

No O2, inefficient, low capacity

Aerobic used during normal work (exercise) levels, anaerobicduring extreme demands

Anaerobic metabolism -> lactic acid (pain, cramps, tremors)


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Causes of bo

muscle fatigu

Excess am

The numbe

loadingForming a

/ forces


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Apply Newtons Law

Use RULA (Rapid Upper Limb Assessment)

Use REBA (Rapid Entire Body Assessment)

Apply advanced Newtons Law

Manual material handling (NIOSHs Law)

Simulation


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Biomechanical models are mathematical models of the mechanic

properties of the human body.

Biomechanical models allow one

quantitatively with established meth

physics and mechanical engineering and thus can serve as an an

tool to help job designers identify and avoid hazardous job situat


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1. A mass remains in uniform motion or at rest until acted on by a

unbalanced external force.

2. Force is proportional to the acceleration of a mass.

3. Any action is opposed by reaction of equal magnitude.

:

When a body or a

body segment is

not in motion

The sum of all external forces the object must be equal to

The sum of all external momen

on the object must be equal


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Suppose a person is holding

a load of 20-kg mass with

both hands in front of his

body and his forearms are

horizontal.

Calculate Relbow and Melbow !


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(forces at the elbow) = 0

-16 N 98N + Relbow = 0

Relbow = 114 N

(moments at the elbow) = 0

(-16N)(0.18m) + (-98N)(0.36m) + Me

Melbow = 38.16N/m

W = mg = 20 kg x 9.8 m/s2 = 196 N

Won-each hand = 98 N


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(Chaffin, et.al, 1999)

Mload-to-torso = Wload x h + Wtorso x b

h = the horizontal distance from the load to the L5/S1 disc

b = the horizontal distance from the center of mass of the torso to theL5/S1 disc

Fmuscle x 5 = Wload x h + Wtorso x b

(Suppose : h = 40 cm, b = 20 cm)

Fmuscle = Wload x (40/5) + Wtorso x (20/5)

Fmuscle = 8 x Wload + 4 x Wtorso

(Suppose : Wload = 450 N, Wtorso = 350 N, = 55)

Fmuscle = 8 x Wload + 4 x Wtorso = 5000 N

Fcompression = Wload x cos + Wtorso x cos + Fmuscle

= 450 x cos 55 + 350 x cos 55 + 5000

= 5458 N


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atau gangguan otot rangka me

kerusakan pada otot, saraf, tendon, ligament, persendian, kartilagdiscus invertebralis.

dapat berupa ketegangan otot, inflamasi, da

degenerasi.

Sedangkan dapat berupa memar, mikro fak

patah, atau terpelintir.


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yang disebabkan oleh frekperiode waktu yang lama

otot, dihubungkan dengan

atau usaha yang terus me

bagian tubuh yang sama m

tubuh yang statis;

yang

oleh aktivitas yang sangat

atau pergerakan yang tak


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peningkatan tegangan otot atau myalgia, leher miring atau kaku leher.

gejala nyeri punggung yang spesifik seperti herniasi lumbal, arthiritis

spasme otot.

kumpulan gejala yang mengenai tangan dan pergelangan t

diakibatkan iritasi dan nervus medianus.

Penyakit ini mengenai pergelangan tangan, ibu jari, dan

lengan bawah, disebabkan oleh inflamasi tenosinovium dan dua tendon yang berasa di ib

pergelangan tangan.

Merupakan keadaan yang mempengaruhi bahu, lengan, da

ditandai dengan nyeri, kelemahan, dan mati rasa pada daerah tersebut keadaan inflamasi tendon ekstensor, tendon yang berasal dari siku len

berjalan keluar ke pergelangan tangan.

terjadi apabila ada penekanan pada daerah lumbal yaitu L5 dan S1. A

pelaksanaan pekerjaan posisi tubuh membungkuk ke depan maka akan terjadi penekana


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p3 - ergo - biomechanics

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