Supertraining

--- In [EMAIL PROTECTED], "Mark" <[EMAIL PROTECTED]> wrote:
>
> Can someone point me in the direction of a good analysis of elbow 
> position during bench press?  Thanks.
> 

****
Dr McLaughlin's book "Bench Press More Now" is very good.  

Website link: 
http://www.usapowerlifting.com/newsletter/13/coaching/coaching.html

Absracts (A number of which were from David Sandler):
 
Wagner, et. al., 1992
– Optimal grip distance appears to be at 200% of biacromial distance
– Earlier studies reported that arms should be at 90o elbow flexion 
and 90o arm abduction (frontal plane), this agrees with this study 
finding near the 200% mark
– Experienced lifters prefer wider grips and show greater force 
production
– No correlation between anthropometric measurements and optimal 
position
– Grip width inversely related to bar-shoulder displacement, directly 
affecting shoulder moment,however, may not be a factor in 
inexperienced lifters
– Sticking region is shorter at optimal grip, later on at closer grip 
and earlier at wider grip

Madsen N, McLaughlin T 
Kinematic factors influencing performance and injury risk in the 
bench press exercise 
Med & Science in Sports & Exercise. 16(4):376-81, Aug 1984. 
The purpose of this research was to identify kinematic factors that 
could be relevant to performance and injury risk in the bench press. 
The methods used included: use of high-speed, 2D cinematographic 
procedures to record the performances of 36 subjects (19 experts and 
17 novices), determination of the kinematic and kinetic differences 
between the groups, and identification of a rationale describing how 
those kinematic differences could lead to the kinetic differences. 

Kinematic factors so identified could influence performance and 
injury risk. 
In addition to the fact that experts were able to lift 79% more 
weight than the novices, the pertinent KINETIC DIFFERENCES included 
the following: 

1. the difference in peak force exerted while lowering the bar was 
only 43%; 
2. the difference in peak force exerted while raising the bar was 
only 45%; 
3. the difference in minimum force exerted while raising the bar was 
87%. 

There was no significant difference in torque required at the 
shoulder. 

The relevant KINEMATIC DIFFERENCES were: 
1. the expert group maintained a smaller bar speed while lowering the 
bar, 
2. the expert group used a bar path closer to the shoulders; and 
3. the expert group used a different sequence of bar movements. 
The roles of these kinematic factors in the bench press merit further 
investigation. 

===========================

Biomechanics of Bench Pressing
• Wretenberg, et. al., 1996
– Several muscle groups and joints work together during the movement.
– Combined force causes the bar to travel vertically
– Synergistic segments work together to produce force.
– Learned patterns of muscle contraction for proper technique.
– Force is not produced at a constant rate.

========================

• McLaughlin, et. al., 1977
– It has been well established that these variations are due to 
an "unweighting" that occurs as the bar velocity
changes due to acceleration
–Force applied to the bar drops due to multisegment leverages and the 
interaction of single and dual joint muscle

=================

McLaughlin and Madsen, 1984
– Shoulder torque much greater in larger lifters
– The larger lifter touches the chest lower on the sternum
• These differences may be attributed to the grip width restriction
• Does not mean that wider grip reduces shoulders torques
– Larger lifters generated more power by the velocity component (not 
by increased load)
• However, segmental lengths were not considered against vertical bar 
distance
–Not Discussed, but graphs reveal longer force application by 
experienced lifters

====================

Madsen and McLaughlin, 1984
– Bar path position relative to shoulders
• Even with much greater loads, shoulder moments were not greater in 
advanced lifters – a modified movement must be made to avoid this
– Sequence of muscle group force production contributing to bar 
movement during ascent
– Degree of control in lowering the bar
– There is a sticking point
–Grip may also play a role

=====================

Wilson, Elliot and Kerr, 1989
– Many muscles interact with one another and the nature of the joint 
itself, will cause a non-linear motion.
– A more linear path is recommended
• expert bench pressers modified the bar path and body position so 
that the muscles involved were able to work more effectively
throughout the movement (Madsen & McLaughlin, 1984).
– EMG data showed the pectoralis muscle continues to exert force 
throughout the motion.
– Triceps and deltoid lose force production.
• This indicates that there is a transition period where the muscle 
is at a disadvantageous force producing position.
–Greater loads showed increased triceps and deltoid activity

====================

Wilson, Elliot & Wood 1991,
– Elastic energy is stored in series elastic components (SEC) during 
delay periods cross-bridge linkages detach and thus elastic strain 
energy dissipates as the cross bridges pull apart after a certain 
length of time.
– Dissipation of stored energy can be calculated and was tested by 
imposing different delay periods
– 35% force reduction in SPBP as compared to the RBP and even greater 
reduction in LPBP
– 14.5% greater load to be used for the RBP as compared with the PCBP 
lift
– A pause duration of 0.35s would cause about a 25% decay in prior 
stretch augmentation and that a 0.9s delay would cause a 52% decay

==================
Jamie Carruthers
Wakefield, UK