I was ploughing my way through Supertraining again and came across this interesting piece of information.
The training effect from performing isometrics at long muscle lengths is significantly greater and crosses over to a larger angle range.
Is this another arguement for deep squatting where the gleutes and vasti (but not the hamstrings or rectus fem) are on stretch? Additionally, how many quarter squats are required to equal the time under tension of one full squat?
it looks to me, the time under tension would be greater, but the rate/speed of movement would be slower because if there is tension from the bands the entire length of movement then where is the emphasis on the quick movement of the hips as to train specifically. The full squat looks to be an option for total devolpment but to devolp/train the hips to fire under greater loads (tension/weight). then one could use a progression as the season went on. but not for extended periods say a month with bands? then could integrate the full squats again possibly
Why do you want to maximise CNS stress?
I think this is one of the reasons for Jay Schroeder using isometrics in extreme positions.
Why the somewhat excessive periods in the position holds (i.e., 1-3mins)? e.g., the iso-hold lunge.
greater “overload”
Why more overload; isn’t such counterproductive?:
Medvedev et al. have reported that static exercises can have a negative impact on dynamic exercises due to the differences in neuromuscular “regulation.”
Some authors have also suggested including Zatsiorsky, Ivenov (1974), Siff, Verkhoshanky that in non-explosive isometrics should be no longer than 6-8 secs after that one’s ability to sustain force decreases. Bondarchuk also states:
‘The duration of these exercises (referring to static work) using any level of internal muscle tension stops at 5-6sec…When using isometric exercise one should employ body positions that correspond to the competition movements hardest segments…’
Furthermore, if Schroeder is holding the positions in extreme positions as one of the members has noted, isn’t this a form of static stretching? We know that the latter causes a decrease in one’s ability to produce force and RFD. Tidas and Shoemaker (1995) also found that following isometric exercise there is a decrease of muscle power by up to 60-70%. Don’t have the full study:(
Why does Schroeder include static work prior to dynamic work? Vorobyev included isometrics prior to dynamic work, but not for such long periods and at varying positions? Isometrics do tax the neuromuscular system.
To add further confusion Ivenov (1974) reported in Medvedev that if the static tensions are included in the general training, they should be done after technique exercises; and, after each static contraction, one should do a relaxation exercise? Might isometrics recruit differing muscle groups (Basmajian, 1978).
Why does Schroeder also do ice massage after static work as well if it precedes dynamic work (i.e., rebounds)? We know that muscles optimally function at certain temperatures – surely such is contraindicated to preceding dynamic work? Siff et al. have reported dynamic exercises take place more efficiently at higher temperatures?
What are the structural benefits are gained from these ‘long hold’ isometrics? There is little lactate accumulation / blood flow? Muscle breakdown?
Yes - I think the reccomended is within 15 deg. of the max ROM?
Correct me if I’m wrong - JS is using isometrics etc to develop footballers and team players for situation where dynamaic and ballistic forces are the norm.
Almost every explosive, agile movement wherether contact or collioson enforced is preceded by a rapid absorbtion (eccentric) phase and very short pause (isometric), thus the focus is on this transferral of energy.
I am only going by what I have read - so I know less than others - but hthis is my understanding -
Exerting a force as in isometrics is a little different from normal static stretching.
I think it is more a case of ‘Dynamic work FOLLOWING isometric work’ rather than the other way around, so that the cyclical energy transferral pattern is preserved and the isometric phase of the sports specific action doesn’t lengthen in practice.
As I understand ice is used during eccentric training not statics and is used to permit extensive ecc work and prevent inflamation.
This is an ‘example’ of one of Jays programs
PRIMARY METHODICS SCHEDULE
Isometric : 1-3 Minutes
Ice Massage: 3 - 5 Minutes
Rest 4 -6 Minutes: Specialized Drinks
Rebound Technique: 3 Minutes Total Performance [No Rest Time Included]
Rest 4 - 6 Minutes: Self Massage
3 x 1 x 80% 10 Count Eccentric, Followed By Rapid Concentric Phase. Use
Vibrator Massage Between Sets
3 x 2 x 90% Manual Overspeed, Normal Eccentric Phase,[ Concentric Phase Must
Be Performed in 25% Of Normal Performance Time]
ANCILLIARY METHODICS SCHEDULE
Perform A Normal Eccentric and Then Hold For 3 - 10 Counts And Perform A Fast
Concentric, For A Total Of 3 Sets Of 3 Reps
Perform the Following Ancillary Exercises: Russian Twist, Glute-Ham Raise,
Barbell Row, Barbell Curl
Perform These Exercises On Monday, Tuesday, Friday, Saturday
MASTER PERFORMANCE SCHEDULE
Weeks 1 and 2 Perform As Is Written
Weeks 3 and 4: Drop Slow Eccentric On 80% Performance, Manual
Overspeed Increases To 105%
Weeks 5 and 6: Drop The Isometric
Weeks 7 and 8: Perform 2 X 1 X 95%, 2 X 1 X 105%, 2 X 1 X 110% With No
Ancillary Work
WEEKLY PERFORMANCE SCHEDULE
Isometric
Rebound
Primary
Monday:
One Legged Squat
Russian Lunge
Squat
Double Bounce
Tuesday:
Wide Dip
Close Grip Bench
Bench Press
Top & Bottom
Wednesday:
Deadlift In Cage
Low Squat Foot Jump
Deadlift
Top & Bottom
Thursday:
Off - Restorative Measures, Active Rest
Friday
All E.D.I., All Primary - 5 Sets
Saturday:
Rebound Push-Ups,
Russian Lunge - 200 Of Each, Perform Throughout The Day
Sunday:
Off Restorative Measures
Again - this is for a rugby team I think and possibily taken out of context.
There is no protocol for the ice massage elements etc. - so only limited definite conclusions can be drawn from this.
There is alot of unexplaned elements -
For example - specialised drinks - this basically covers every liquid except water - most proabably a very soln low protein and carb drink though.
What are menat by the following - rebound technque, EDI, is the ice and rest mutally exclusive, top and bottom???
Jay always follows iso holds with an explosive dynamic movement.
Iso holds improve immediately follwing dynamic movements - Static Dynamic principal
Probbaly to do with muscular/tendon unit stiffening - at a guess.
All eccentric/concentric switching always has a phase of isometics before the reversal begins.This is what he is probably targeting
As far as overload goes - instead of using extra weight Jay uses greater duration to serve the same purpose
in the iso holds. Well it must work for him 
Well I did read somewhere that Jay learnt a lot from Yessis, so maybe we should ask him about this 
Each motor regime (EF,IF,CF) has to be developed separately and simultaneously, then intergrated to function as one corresponding unit. They are separate entities that are stored individually within the CNS, thus they need to be developed in this manner. This is the beauty of the Conjugate Sequence System (CJSS), since Yuri Verkhoshancki originally designed it specifically for this reason.
When training these regimes one has to remember that there is no correlation between max strength and speed, and static and dynamic strengths. They are on opposite ends of the spectrum. But traits or regimes located close to one another, correlate more directly. For example, max speed(0-20%), starting strength (20-40%), transitional strength-to much variability here for anyone to quantify (40-60%), accelerative strength (60-80%), and max strength (80-100%). From these regimes, traits arise through an accumulation of training-effects. For example, max strength and accelerative strength are easier developed then starting strength (SS). But when SS is effectively developed and combined with reactive ability, these traits converge to form a brand new neurological regime called explosive strength. A lag in the development of one area throws the whole system out of whack, and delays the onset of explosive strength. Another ex/myotatic stretch reflex correlates highly with eccentric strength.
Your on the right track with your thinking but I would teach the movement backwards. Zakharyents (1962) said, “the better trained the athlete, the more precise and efficient the use of the reflex muscle tension (feed-foward) during eccentic work.” First, teach them to deform their muscle and store elastic energy. (EX/a bow- in order for a bow to propel an arrow it first must be deformed by pulling it in the opposite direction. This creates strain energy. In the drawn position, the arrow contains potential energy and upon release it has kinetic energy.) I would do this by teaching the landing first in an athletic position iso-squat hold. Teach the glutes/hams/calves to accept and store the strain energy. Until this is accomplished, kinetic energy can’t be fully utilized. Then progress to variations of single response VJ landings and practice “landing soft (to absorb force)” and “sticking the landing (to break the eccentric descent).” Eventually progress to a low-lying box for the altitude landings and increase box height as performance warrants (.7m to 1.2m).
But with this said, Dyhre-Poulson et al (1991) stated, “… the enhancement of positive power (CF) and economy of positive work immediately after eccentric-stretch and dissipation of energy of the body to protect passive anatomical structures appear to be conflicting demands, and maximizing one property would lead to compromising the other.” In other words, BALANCE your EF and CF jumps. So train them simultaneously, thus the beauty of the CJSS.
I recommend highly looking at explosive isometric tension! This is result of combining neurological regimes, and a different post.