1. Speaker Name: Cindy Lawton Speaker Title: BCPE, PT, OCS, MA ( LA-UR-15-22284)

2. Outline Injury information – Glovebox worker data Shoulder anatomy and muscle length bio-mechanics Rotator cuff ratios and results Engineering solution

3. PersonWork Environment Stress/ Job satisfaction Money Habits Outside Activities Body Type Exercise Pre-existing Conditions Job Tasks Equipment Shift Breaks Communicating Needs Management Support Nutrition Who is going to get hurt?

4. LANL Glovebox 700 Operating Gloveboxes 400 trained glovebox workers 150-200 daily workers

5. 5 Pencil Drop – Typical GB Activity

6. Percentage of Workers Reporting Symptoms vs. Years as a Glovebxox Worker. Repetitive Injuries

7. Glovebox Injury Data

8. Injury Information Previous 18 months before 2006 – 18 recordable injuries Since 2004 – 57 recordable glovebox injuries

9. Shoulder and Elbow 1.Highest severity – surgery and career ending 2.Highest frequency ( 23 shoulders & 35 elbows) 3.Most costly :  Shoulder surgery direct and indirect cost $120,000 to $200,000 approximately  Elbow surgery direct/indirect cost $100,000 approximately

10. Muscle Length Tension

11. 11 Mid-range – muscle is capable of producing optimal force Shortened Muscle (Too much overlap) Mid-range Muscle (Optimal overlap) Lengthened Muscle (Too little overlap) Cross-Linking of Myofibrils

12. 12 GB worker - Muscles of the Mid-Back This is copyrighted© 1999 by Wesley Norman, PhD, DSc

13. GB Worker - The Rotator Cuff Most glovebox-related shoulder injuries involve the rotator cuff Slide 13

14. Strength Ratios Healthy shoulders - 1.5 : 1 or 3 : 2 ratio of internal rotator strength to external rotator strength

15. Testing Strength Ratios The arm position: 30º of forward flexion and 30º of abduction Worker pushed into force gauge/researcher stabilized arm Utilized the average of 3 trials for both Int Rot. and Ext Rot. to determine ratio.

16. Shoulder Ratio Results Glovebox workers have shoulder strength ratios significantly different from the healthy norm of 1.5 ( α = 0.0001 ) Range: 1.5 to 4.1 Mean: 2.7

17. Shoulder Ratio Results

18. Right shoulder ratios were more aberrant than left Right mean: 2.8 Left mean: 2.6 Slide 18

19. Shoulder Ratio Results – Symptoms The majority of workers with ratios ≤ 2.5 were asymptomatic Symptom incidence increased in workers with ratios ≥ 2.5 Slide 19

20. Ratios – symptoms – years GB work

21. Study Summary Glovebox workers have shoulder strength ratios significantly different from the healthy norm Only 2% of GB workers have the healthy 1.5 ratio Symptomatic workers have ratios that are more skewed than those of asymptomatic workers – especially early in career

22. Solution Development Glovebox tasks that stress the shoulders: Lateral transfer of items - passing items down the length of a glovebox Heavy lifting - items heavier than 15lbs Repetitive motions - cleaning windows  Activity at extreme range of motion - transferring items into/out of airlocks

23. Air lock – Transfer Tunnel Location of an airlock

24. Shoulder Position.

25. Air Lock Sliding Tray $ 175,000 to design and manufacture the trays.

26. Summary There is prevalent imbalance in shoulder strength ratios among GB workers. Symptoms are more prevalent among workers with more aberrant shoulder strength ratios. The abnormal ratios are most likely contributing to shoulder symptoms especially early in a GB workers career. Utilizing strength ratios can be utilized both as a medical screen as well as to initiate engineering control projects.