[FONT="]The Affect of Grip Width Performance on Bench Press Performance & Risk of Injury[/FONT]
[FONT="](Green & Comfort)[/FONT]
[FONT="]1.[/FONT][FONT="] What does the musculoskeletal system of the glenohumeral joint act to do during the action of the bench press?
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-[FONT="]Provides a base of support for the motion of the barbell
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[FONT="]2.[/FONT][FONT="] Performance of the bench press may place the glenohumeral joint in a position approaching high risk of injury. Define this position.
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-[FONT="]90 degrees of abduction combined with end-range external rotation of the shoulder during bench press and associated exercises may increase the risk of acute and chronic shoulder injuries
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[FONT="]3. [/FONT][FONT="]What is the definition of biacromial width? And how does this relate to the at risk position?
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-[FONT="]Biacromial width is the distance between acromion processes. A bench press grip of >2 biacomial width increases shoulder abduction above 75° placing the shoulder near the compromised ‘at risk position’. However a grip spacing of <1.5 maintains shoulder abduction below 45°.
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[FONT="]4.[/FONT][FONT="] List some chest & shoulder exercises that have been reported to produce pain? What do they all have in common
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-[FONT="]Military press behind the neck, incline flyes and wide grip bench press all place the humerus into abduction and external rotation.
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[FONT="]5.[/FONT][FONT="] What resistance training methods can further increase the risk of injury and why?
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-[FONT="]Use of forced repetitions, supersets, compound sets, eccentric contractions and multiple set chest exercise variations increase the loading on the skeletal and musculo-tendinous structures will increase the risk of injury especially if used regularly.
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[FONT="]6.[/FONT][FONT="]Which of the aforementioned training methods may place the pectoralis major at considerable risk of rupture and why?
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-[FONT="]Regular use of eccentric repetitions may increase the risk of rupture because pec major is most susceptible at the musculo-tendinous junction during eccentric loading.
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[FONT="]7.[/FONT][FONT="] How does altering grip width from wide to narrow affect muscle recruitment?
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-[FONT="]Reducing grip width from 190% biacromial width to 100% doesn’t significantly affect pec major or anterior deltoid recruitment however the reduction in width significantly improves triceps brachii recruitment.[/FONT][FONT="]
8. What is the IGHL and what is its funtion?[/FONT]
-[FONT="]The Inferior Glenohumeral ligament attaches to the inferior aspect of the humeral head and the anterior glenoid and labrum. It is responsible for providing anterior stability by maintaining the humeral head in the gleniod fossa but more importantly restraining anterior translation at 90° abduction. Damage to the IGHL reduces anterior stability.
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[FONT="]9. [/FONT][FONT="]Define atraumatic osteolysis of the distal clavicle.[/FONT]
-[FONT="]A stress-failure syndrome; a pathological process of bone destruction to the subchondral bone of the distal clavicle.
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[FONT="]10.[/FONT][FONT="] What may contribute to osteolysis of the distal clavicle?
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-[FONT="]The excessive stresses on the acromioclavicular joint via the extension mechanism of the shoulder during the eccentric phase of the bench press and repetitive microtrauma during weight lifting. More specifically repetitive movements performed with the shoulder at 90 degrees abduction, a grip width >1.5 times biacromial width and external rotation appear to cause this injury.
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[FONT="]11.[/FONT][FONT="] What portion of the Pectoralis major fibres are most at risk of rupture and why?
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-[FONT="]The inferior fibres of the pec major are most at risk of rupture due to their twisting orientation that converges on the proximal aspect of the humerus.
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[FONT="]12.[/FONT][FONT="] At what point of bench press execution do ruptures of the pectoralis major occur?
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-[FONT="]The injury occurs during the beginning of the concentric phase following eccentric lowering stressing the inferior fibres. Ruptures occur at the tendinous insertion on the humerous when the pec major is stretched and contracted.[/FONT][FONT="]
13. Describe the correct bench press technique to minimise injury
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-[FONT="]<1.5 biacromial width[/FONT]
-[FONT="]Controlled descent to lower portion of pectorals (reduce abduction & external rotation)[/FONT]
-[FONT="]The bar should move through same plane of motion in ascent, albeit more rapidly.[/FONT][FONT="]
14. What difference does altering wide to close grip have on bench press 1RM performance and muscle EMG results?
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-[FONT="]Non-significant difference was noted between 100% & 200% biacromial widths. No difference in pec major sternocostal head EMG results however the narrow grip improved the activity of both the clavicular head of the pec major and the triceps brachii.[/FONT][FONT="]
15. What does research suggest about incline bench press on muscle activation?
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-[FONT="]The clavicular head doesn’t show greater muscle activation during incline press however the activation of the sternocostal head is diminished, suggesting that this exercise may be un-necessary unless specific for sports performance.[/FONT]