Repetitive Motion

[Audio] In this session, we will be discussing repetitive motion, what it is, what the risk factors are, and the interventions that can be taken to avoid developing musculoskeletal disorders from it..

[Audio] Hence, the objectives of this lecture are for you to be able to assess tasks that require repetitive motion of the upper limbs; understand the common risk factors in repetitive work; and propose possible interventions to prevent and control musculoskeletal disorders from repetitive movements..

[Audio] You have learned in Module 2 the different risk factors in the development of work-related musculoskeletal disorders. As a review, the risk factors are postural stresses, forceful work, contact stress, vibration, and repetitive motion, among others. So, what is then repetitive motion?.

[Audio] Repetitive motions. Repetitive Motion. Work that requires: The use of same group of muscles over and over again during the working day, or Frequent movement to be performed for prolonged periods Contributing factors include: Duration and speed of repetitive movements Number of muscles involved Required force.

[Audio] Two conditions will occur if we are doing repetitive tasks: depletion of energy and build up of metabolic wastes and changes in the soft tissues. These two will lead to muscle fatigue. Without proper rest, the muscle will eventually be damaged, which is an increased risk in developing work-related musculoskeletal disorders (WMSDs). If the repetitive task is rapid and prolonged, there will be no sufficient time for recovery of the muscles..

undefined. Examples. Repetitive exertions Repeated hammering.

[Audio] A tool that we can use to assess risks due to repetitive task or motion is the Assessment of Repetitive Tasks (ART) Tool. This is developed by Health and Safety Executive. The ART Tool is designed to help assess tasks that require repetitive movements of the upper limbs (arms and hands). It is also helpful in assessing some of the common risk factors associated with the development of upper limb disorders..

[Audio] The ART Tool is suitable for tasks that involve the upper limbs, hence the name "assessment of repetitive tasks of the upper limbs". Also, this is suitable for tasks that are repeatedly done every few minutes and that occur for at least one to two hours per day or shift. This tool is not intended to be used for the assessment of Display Screen Equipment or DSE. REMINDER: It is important to remember that while there are existing ergonomic tools, aside from that we should be knowledgeable in how to use it, we need to know its scope (kung para saang task/s lang ba ito), applicability (kung may specific task ba or specific group of workers or specific industry), and limitations (saan hindi pwedeng gamitin). We should also know if the source of these tools are from legitimate sources or from the right authority/ies..

ART Tool. Repetitive tasks are typically found in: Assembly Production Processing Packaging Packing Sorting Work involving the regular use of hand tools.

ART Tool. Assessment guide Repetitive tasks are made up of a soqtn•rce of limb actons, of fairty short dÄtn. whiah are repeated over and 0'v•er agdn. and Ere almost atways tre sarne (og stitchirg a piece of cbt-t. rranufacturing one part, packaging cro item). • ART is most suited for tasks that: • irtvdve actions of I-oper limbs; • every minutes. or more freqæntty; and • occu for at least day or shift. • The tasks are typeaey fourd in assgnbly. production, processng pac*aging. pækjng and sating vork, well as work irrvo\'ing regular use of hand toes. • ART is not for display screen equipment (DSE) assessments..

ART Tool. Composed of three sections: Flow Chart Provides an overview of the assessment process..

ART Tool. Composed of three sections: Task Description Form and Score Sheet Provides a place to record information about the task and findings of the assessment..

[Audio] The assessment guide is split into four stages: Frequency and repetition of movements Force Awkward postures Additional factors For each stage, determine the level of risk for each risk factor. The levels of risk are color-coded according to its classification: Green for low level, Amber for medium level, and Red for high level. Each level has its corresponding numerical score, which is important to be noted during the assessment as these will be computed at the end of the process..

[Audio] For the repetition of the movement of the arm and hand, it is important to remember that movement of the fingers is NOT INCLUDED in the assessment..

[Audio] The second stage of the assessment guide is the force, which is classified to light, moderate, strong, and very strong. Unlike Stage A, Stage B involves actions that require muscle effort of the arm, hand, or fingers. We can ask the worker the level of force involved in each action..

[Audio] The level of force exerted may also be determined by using these written descriptions as guide..

[Audio] RECAP: In the Work Posture module, it was mentioned that neutral postures should be maintained as awkward postures put stress on the worker's muscles and joints, which can lead to fatigue. The third stage in the assessment guide is on awkward postures. In this stage, the amount of time a worker spent in awkward postures are being determined. The specific body parts that are assessed are the: Head/neck Back Arm Wrist Hand/finger grip You may find this easier to assess we also did this yesterday sa RULA worksheet..

[Audio] When can we say that the neck is in an awkward position? [Referring to the photo] If the neck is bent or twisted (side arrows) and is not in its neutral position (dashed line). If in an almost neutral position: 0 Bent or twisted (15 to 30% of the time): 1 Bent or twisted more than half of the time (more than 50%): 2.

[Audio] Back posture is awkward if there is a twisting or bending of more than 20° angle..

[Audio] The arm is in awkward position if the elbow is raised to around chest height and if the arm is unsupported..

Assessment Guide Stages C. Awkward Postures. C4. Wrist.

C5. Hand/finger grip. Assessment Guide Stages C. Awkward Postures.

Breaks Work pace Other factors Duration Psychosocial factors.

Assessment Guide Stages D. Additional Factors. D1. Breaks Significant changes or pauses in arm or hand activity, including Structured breaks, e.g., meal breaks Time spend performing other tasks that do not involve similar repetitive arm movements, e.g., visual inspection task.

[Audio] This factor is subjective as we can only know this by interviewing or talking with the worker/s involved. If the score is 1 or 2, ask for more information about this work aspect..

Assessment Guide Stages D. Additional Factors. D3. Other factors, L and R arm Examples: Gloves affecting grip Tool, workpiece, or workstation that causes compression Exposure to cold or draughts Inadequate lighting levels.

Assessment Guide Stages D. Additional Factors. D4. Duration Amount of time a worker performs a repetitive task in a typical day or shift, including breaks.

Assessment Guide Stages D. Additional Factors. D5. Psychosocial factors Not given a score, but should be considered and recorded in the score sheet, if present Examples: Little control over how the work is done Monotonous work High levels of attention and concentration Lack of support from supervisors or co-workers Excessive work demands Insufficient training.

Flow chart Stage A Frequency/repetition START hfrequent SCYTE hta-mittent Frequent (eg reg_iar movement some pauses) Vay contiru»us SiniW rnotion gÄta-ns rFai 10 rnn_Jte cr Ess motion patterns r+eated f 1 to 20 tines minute Sinilz rnotion pdtarB more ttH120 tines per mi-ute Stage B Force See grid page 5 of the See grid cm page 5 of the assessment guide See grid 5 of the zsæsrnalt glü Stage A Frequency score A1 A2 Left hand Right hand Stage C Awkward postures Stage D Additional factors Left Right Left Right 6-12 -12 c ck ger A&-rxzt Bant cr twisted part of time Bent twistexi rTue ttw-' half ttE tine rmRrd Bant forward. sideways cr ed pat of the time Bant foruard, twisted rrx:re half tine Ebon close to the body the am is ra away body part of the time EDH away frun ttE txxiy rmre ten of the Anst ranrd/stra@t Balt cr ±viated part of tirne Balt rrue ttw-' of the tine Powa g*:) ro at*vard or wide fing« part of the the Fhh v.'i& fu mae theri time Stage C Posture score —I Left Right fifi c tors Less thul 1 ca-itru:us work f to less than 2 hours of inuous work to less than g of 3 to Ess 4 turs wuk 4 rrx:re tours of Nev« to with the v.ork metirnes difficult to ke%) up with the work Offen cfiffx:un to up with the vork No factcrs f factor present 2 n-ue Wors Less 2 hars 2 to less than 4 hours 4 to 8 ours More than 8 hours Stage B Force score Stage D Additional factors Dl 02 D3 Task score Duration Left Right x 0.5 x 0.75 x 1.5 Exposure score.

[Audio] In the score sheet, we have to indicate the color band and its corresponding numerical score in each of the stated risk factor. Then we have to compute for the task score. This can be done by adding the scores of A1, A2, B, C1, C2, C3, C4, C5, D1, D2, and D3. Do not combine the scores for the left and right arm. It should be kept separate! The exposure score can be computed by multiplying the calculated Task Score and the Duration Multiplier. The Duration Multiplier is same score as D4..

Interpreting the Exposure Score. Exposure Score Proposed Exposure Level Interpretation 0 – 11 Low Consider individual circumstances e.g., new and expectant mothers, new workers, returning to work, etc. 12 – 21 Medium Further investigation is required >22 High Further investigation is required urgently.

[Audio] Again, the purpose of the ART Tool is to identify the significant risks and reduce the level of risks. In the previous slide, we knew how to compute for the task score and exposure score. But why is it important to know these scores? Because it help us to prioritize the tasks that need the most urgent attention. It can also help us to check the effectiveness of any improvements..

Interventions. If the tasks require attention, look for “higher order” solutions.

Interventions. Simple and cost-effective preventive measures Examples: Changing the height of the workstation Placement of work items that can allow or facilitate better arm postures Involve the workers exposed to repetitive tasks in the development and implementation of risk-reduction measures Develop systems for early reporting of symptoms, proper treatment, rehabilitation, and return to work.

Let’s Practice!.

Case. Luz works in a food manufacturing company that operates from 08:00 AM to 05:00 PM, six days a week. In an eight-hour shift, workers are provided with 1.5-hours working break. On one occasion, she went to the clinic and asked for medication for back pain. She mentioned to the nurse that it sometimes make it difficult to keep up with her work..

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[Audio] In this case scenario, we are going to assess both the right and left arms. What did we notice with the arm movements? Almost continuous… In fact, we can see that there is almost an equal time interval for each movement. Is the movement of the right arm same with the left? Yes. What will be our score then? Let's now assess the repetitiveness of the motion. The same motion or movement is repeated for more than 20 times for both arms. So our score would be….

[Audio] Let's proceed with Stage B or force. Assuming that we were not able to interview the worker, we would just have to look at the actions of either her arm, hand, or fingers. Based on the video we had earlier and from this snippet, we can see that she pinches the dough bread until it forms into a croissant. The level of force exerted is… MODERATE. And since this action is being done almost all the time, the score we will give is 8..

[Audio] We will then assess for awkward postures. We observed that the head and back is almost in its neutral position, so our score would be 0..

Red. 4. Red. Score sheet Enter fre cdour band md nun-ercal score for each risk fætor in t±le below. Follow tt-e instrucbons on page 10 to determine the task score and exposure msk factors Ad A2 C2 CS C4 CS 01 02 03 04 06 Arm Repetition Hed'reck posture Back posüe Arm postwe Wrist posture Hmd.lfinw yip Breaks Other factors Left arm Task score x Right arm x Exposure score Psychosocial factors.

Eight-hour shift, with 1.5 hours working break.. Red.

Other factors present? Prolonged standing Noise Fine, precise movements of the hands and fingers Cold temperature.

Task score = A1 + A2 + B + C1 + C2 + C3 + C4 + C5 + D1 + D2 + D3.

Exposure Score = Task Score x Duration Multiplier = 39 x 1 Exposure Score = 39.