This document summarizes research on shoulder strength and flexibility ratios. It discusses key muscles involved in scapula stability and presents data on ideal pull to push ratios and rotator cuff strength ratios. Sample exercise progressions are provided to develop posture, scapula control, stability, and strength in a balanced manner. Program design should focus on control before strength and simplify movements until proper patterns are established to prevent muscle imbalances and injury.

1. Mark McKean PhD CSCS Upper Body Structural Balance RESEARCH

2. Session Summary This session will cover Shoulder strength & flexibility research The relative ratios for shoulder strength & flexibility. Key issues for program design

3. Research summary

4. Research Areas Scapula position/stability Shoulder strength Shoulder flexibility Other notes

5. Scapula position/stability

6. Muscles Involved Trapezius and serratus anterior most important stabilisers acting on scapula thoracic joint (Mottram 1997) The external rotators function in a synchronised pattern, with the deltoids to creata force couple necessary for normal, unrestricted motion (Kolber 2009). The deltoid provides dynamic stability with the arm in the scapular plane. (Lee 2002)

7. The rotator cuff and biceps are active 0.092–0.215 s prior to the initiation of the actual movement and 0.112–0.034 s prior to onset of deltoid and pectoralis major activity when performing shoulder rotations (David 2000) The infraspinatus, subscapularis, and latissimus dorsi act as stabilizers during flexion; the subscapularis acts as a stabilizer during external rotation and the supraspinatus during extension. (Kronberg 1990)

8. Program Design Exercise routines that emphasise the deltoid musculature and neglect the rotator cuff may create an imbalance of the deltoid–rotator cuff force couple, leading to altered muscle coordination, restricted AROM, and impingement of the shoulder complex during arm elevation (Kolber 2009) Increases in rotator cuff muscle forces tended to improve stability whereas increases in deltoid or pectoralis major muscle forces tended to further decrease stability (Labrioloa 2005)

9. The mid and posterior heads of deltoid should be strengthened vigorously in anterior shoulder instability...., because they provide more stability generating higher compressive force and lower shear force... (lee 2002)

10. Scapula stability exercises and thoracic curve correction should be done before rotator cuff exercises (Kibler 1998) Ideal scapula position yet to be determined but it is not in its inner range of lower traps, and “down and back” is not an appropriate command (Mottram 1997)

11. Imbalances Overhead athletes with impingement symptoms demonstrated strength deficits and muscular imbalance in the scapular muscles compared with uninjured athletes. (Cools 2005) Significant difference in awareness of scapula position between dominant and non-dominant shoulders. (Boyar 2007)

12. Shoulder strength

13. Pull:Push Ratio Rugby players – bench press to pull ups 1:1(Baker 2004) Kayak paddlers – bench press to pull ups females - 1:1.47, & males 1:1.29 (McKean 2009) Normal population – pull:push ratio using dynamometer 1:1.12 (Peebles 2003)

14. Shoulder Strength Ratios If use a key predictor exercise - 1RM Pull up = 100% (kayakers – McKean 2009) 8 RM Shoulder press - Deltoid – 18% 8 RM External rotation - External rotators – 9% 8 RM Bent over trap 3 raise - Lower Traps – 6%

15. Suggested rotator cuff ratio of internal to external strength is approx 1.3 to 1.6. (Codine 1997, Niederbracht 2008, Barlow 2002, Hughes 1999) Deltoid : External Rotators : Lower Traps 3 : 1.5 : 1 ratio of strength (McKean 2009)

16. Flexion:extension – 1.26-2.22 (depending on angle isometric measure taken 30-60-90 degrees flexed - Hughes 1999) Abduction:adduction – 1.53-2.63 (depending on angle isometric measure taken 30-60-90 degrees abducted - Hughes 1999) Both ratios above increased to a higher ratio with age. i.e. Both extension and adduction movements became proportionally weaker

17. Other RatiosNot published

18. Based on key predictor exercise

19. based on Different predictor exercises

20. Strength Summary A few key issues to remember Upper body structural balance not solely based on numbers but also posture and movement Aim to achieve a steady and progressive change in loads across all lifts Every sport has a different ratio outcome but try and keep Traps and Rotators relatively strong for improved shoulder stability

21. Shoulder flexibility

22. ranges of movement about the shoulder Based on position of assessment done at 900 abduction

23. Other Notes

24. Push pull movements/stabilising showed postural adjustments were initiatedshortly before all focal movements (Cordo 1990) Isometric strength was significantly lower for the Scapula Protracted position compared with the Scapula Neutral position and Scapula retracted position (Smith 2002) By increasing the eccentric external total exercise capacity without a subsequent increase in the concentric internal total exercise capacity, it potentially decreases shoulder rotator muscle imbalances and the risk for shoulder injuries (Niederbracht 2008)

25. Bodybuilders showed an overall loss of shoulder rotation ROM (1660 vs. 1880) and a significantly decreased internal rotation ROM (-110) compared with the control group, and were significantly weaker in lower trapezius strength when expressed as a percentage of body weight. (Barlow 2002)

26. Changes in Shoulder Posture

27. 2007

28. 2010

29. April 2008

31. Oct 2008

33. Key issues for program design

34. Posture Ensure thoracic curve close to ideal before you address shoulder related strength problems Must reinforce correct thoracic curve at all times for all upper body exercises Need to negate the associated and exaggerated movement of thoracic hyperextension when pulling

35. Pattern Control must occur before strength Practice makes permanent – not always perfect Simplify pattern until it can be controlled and perfected Poor movement patterns are the main cause of most muscle balance related issues – i.e. Trying to go too heavy, too quickly, too dynamic, too early before good patterns established

36. Proprioception Teach client to “feel” the exercise, the movement, the stress, and the response of the body Unstable surface and complex movement training is often applied too quickly before client can “feel” a posture or pattern and once complicated by increased proprioceptive demand, loses “control” of the pattern and is unable to develop proper force output

37. Pushing Exercise Progressions Chest press pw Change grip Chest press pl Use 1 arm Change grip BB chest press Change angle Change grip/line DB chest press Change grip Change angle Use 1 arm

38. Sample progression Chest press pin weight Chest press plate loaded – horizontal grip Seated chest press pin weight Chest press plate loaded – vertical grip Chest press plate loaded – alternate push BB chest press – close grip BB incline chest press BB incline chest press mid grip – high bar DB chest press – neutral grip DB incline chest press – horizontal grip DB chest press – alternate arms DB chest press 1 arm

39. Pulling Exercise Progressions Lat pulldown RG Lat pulldown CG Seated row Use 1 arm Assisted pull ups Single arm DB row Change support Pull ups Change angle BB row

42. Sample progression Straight arm wall sags and press Wall/floor angles up and down Bent over trap 3 raise Shoulder rotations – scap controlled – limited ROM Side arm scaption raises - partial to match control Single arm DB scaption press - partials to match ROM control Chest press/lat pulldown/seated row – partials to match ROM control

43. Program Management Develop awareness of posture and ROM client can control Assess ROM, strength ratios either via real testing or subjective assessment depending on stage of client Progress clients according to ability and regress when required

44. Suggested progressions 0 - 6 months 8-15 reps 2-4 sets Up to 70% efforts Slower tempos to develop control eg 4020 Aim for control of shoulder movements and stability as a priority 6-18 months 6-15 reps 3-5 sets Up to 90% efforts Tempos can range up to 2010 still keeping slower eccentric Aim for proper strength ratios and good ROM

45. Program samples

51. Mark McKean Post Doctoral Research Fellow Australian Institute of Fitness Research University of Sunshine Coast mmckean@usc.edu.au