Constructive Resistance

A necessary form of practice to learn effective techniques because without adequate resistance, a novice practitioner will not know if the technique is working. Constructive resistance provides uke-and-tori with appropriate feedback and guidance, a hallmark of the uke-tori relationship in training and practice, necessary to deal effectively with the reality of physical conflict. 

Constrictive resistance is only constructive if it creates scenarios that are close to reality, provide growth and improvement in technique and spirit. The level of resistance must be controlled by the senpai, as the more experienced, so that it is not excessive and allows the practitioner to complete a technique with progressive difficulty. If a practitioner cannot complete a technique under resistance then they never learn it. 

It is also incumbent on the role of sempai to provide negative resistance in a manner that guides the kohai to perform proper movement according the fundamental principles of martial systems, i.e. with alignment, etc. This promotes proper and effective learning of a technique of combination of techniques. 

Another aspect of this type of training is to achieve mastery over many of the fundamental principles such as economic motion, balance, rhythm, positive relaxation, etc. It is about moving from muscular power, i.e. muscling it, to these principles of martial systems that lead to master of the entire system. It is vital to any martial training, and provides those steps or levels one has to travel to reach higher levels - ultimate master. 

Addendum:

PRINCIPLES OF THEORY

Universality, Control, Efficiency, Lengthen Our Line, Percentage Principle, Std of Infinite Measure, Power Paradox, Ratio, Simplicity, Natural Action, Michelangelo Principle, Reciprocity, Opponents as Illusions, Reflexive Action, Training Truth, Imperception and Deception.

PRINCIPLES OF PHYSIOKINETIC

Breathing, Posture, Triangle Guard, Centerline, Primary Gate, Spinal Alignment, Axis, Minor Axis, Structure, Heaviness, Relaxation, Wave Energy, Convergence, Centeredness, Triangulation Point, The Dynamic Sphere, Body-Mind, Void, Centripetal Force, Centrifugal Force, Sequential Locking & Sequential Relaxation, Peripheral Vision, Tactile Sensitivity, Rooting.

PRINCIPLES OF TECHNIQUE

Techniques vs. Technique, Equal Rights, Compliment, Kobo Ichi, Economical Motion, Active Movement, Positioning, Angling, Leading Control, Complex Forces, Indirect Pressure, Live Energy & Dead Energy, Torsion & Pinning, Speed, Timing, Rhythm, Balance, Reactive Control, Natural & Unnatural Motion, Weak Link, Non-Telegraphing, Extension and Penetration.

PRINCIPLES OF PHILOSOPHY

Mind, Mushin, Kime, Non-intention, Yin-Yang, Oneness, Zanshin & Being, Non-action, Character, The Empty Cup.

Bibliography:

Perlman, Steven J. "The Book of Martial Power: The Universal Guide to the Combative Arts." New York. The Overlook Press. 2006.

Alexander, David. "The Four Levels of Aikido Training." CFA, Vol.2 No.25 (Issue #48).