In the course of Alexander evolving his technical language he used a number of interrelated terms such as ‘primary motive power’, ‘primary movement’ and ‘true primary movement’. This entry is only concerned with ‘primary movement’. The term first appeared in 1903 and last in CCC (1923).
‘Primary’ was applied to several words before it finally prefixed ‘control’ in UoS. In ‘Introduction to a New Method of Respiratory Vocal Re-Education’ (1906) he refers to ‘primary motive power’. In ‘The Dangers of Deep Breathing’ (1908) he refers to the ‘primary factor’. In MSI ‘movement’, ‘movements’, and ‘inhibition’ are sometimes primary (also ‘idea’ and ‘principle’, ‘factor’), in CCC several of these and ‘direction’ also appear as primary. In UoS the term ‘primary act’ appears.
There is no single stand-alone definition of ‘primary movement’: meaning has to be deduced from the context in which Alexander discusses it.
The term ‘primary movement’ first appears in 1903, in Alexander’s advertisement for a proposed book (which never materialised). In the advertisement, in describing his ‘new methods’, he mentions ‘a perfect system of physical development, having a correct and natural primary movement for each exercise’.
It would appear that between 1904 and 1907 ‘primary movement’ referred to ‘the proper expansion of the chest’, indicating an indirect way of breathing based on certain principles. A 1904 Daily Express (London) article relating a meeting between Alexander and the singer Violet Elliott also refers to ‘primary movement’. The article indicates that Alexander’s view is that the ‘primary movement of breathing must be thoracic – that is, the thorax or chest-box must be expanded naturally without drawing in any breath by suction’.
A similar view is expounded by Alexander in 1907:
Most people if asked to take a ‘deep breath’ will proceed to—I use the phrase spoken by thousands of people I have experimented upon—‘suck air into the lungs to expand the chest,’ whereas, of course, the proper expansion of the chest, as a primary movement, causes the alæ nasi to be dilated and the lungs to be instantly filled with air by atmospheric pressure, without any harmful lowering of the pressure. 
This view is repeated later in the same article:
Further, these expansions are primary movements in securing that increase in the capacity of the chest necessary to afford the normal oscillations of atmospheric pressure, without unduly lowering that pressure—[i.e.] opportunity to fill the lungs with air, while the contractions overcome the air pressure and force the air out of the lungs and, at the same time, constitute the controlling power of the speed and length of the expiration.
This ‘primary movement’ is preceded and shaped by the pupil’s mental attitude:
At the outset, let me point out that respiratory education or respiratory re-education will not prove successful unless the mind of the pupil is thoroughly imbued with the true principles which apply to atmospheric pressure, the equilibrium of the body, the centre of gravity, and to positions of mechanical advantage where the alternate expansions and contractions of the thorax are concerned. In other words, it is essential to have a proper mental attitude towards respiratory education or re-education, and the specific acts which constitute the exercises embodied in it, together with a proper knowledge and practical employment of the true primary movement in each and every act.
In the same article Alexander makes it clear that other movements follow the primary movement:
. . . (b) that a proper mental attitude towards respiration is at once inculcated, so that each and every respiratory act in the practice of the exercises is the direct result of volition, the primary, secondary, and other movements necessary to the proper performance of such act having first been definitely indicated to the pupil.
This emphasis on the pupil understanding the principles involved and hence having a ‘proper mental attitude’ becomes more apparent in 1908 with an emphasis on the ‘orders’ being primary for the purpose of dealing with ‘movements unconsciously performed’ which otherwise will become primary. The following is in connection with a pupil leaning backwards against a book:
I may briefly explain (a) [definite inhibition] by stating that the teacher will have to deal with incorrect movements unconsciously performed. These movements occurring at the moment when he dictates the orders necessary to bring about co-ordination of the different parts of the mechanism assert themselves and become primary, and hinder the performance of the correct and co-ordinated movements as ordered. It is, therefore, as necessary to order the inhibition of incorrect and unconsciously performed acts as to give orders which will secure the co-ordinated use of the mechanisms involved. Therefore, when the teacher has discovered the errors unconsciously committed by the pupil when beginning to rehearse the correct orders, he will draw attention to them, and give a definite order concerning what is not to be done, e.g. the peculiar bad habit, perhaps of a lifetime. This negative order must precede all positive commands. In other words, the order or orders concerning what is not to be done are to be considered as primary, and those concerning what is to be done as secondary.
Then the act of breathing is not as such primary in the whole arrangement, but becomes subsidiary to the organisation of the whole. From ‘Why we breathe incorrectly’ (1909):
Now here we have (a) the directive agent of the sphere of consciousness, and (b) the use of the muscular mechanisms—the combination causing certain expansions and contractions, and the result being what is known as breathing. It will at once be seen, therefore, that the act of breathing is not a primary, or even a secondary part of the process, which is really re-education of the kinæsthetic systems associated with correct bodily postures and respiration, and will be referred to universally as such in the near future. As a matter of fact, given the perfect co-ordination of parts as required by my system, breathing is a subordinate operation which will perform itself.
In the same article Alexander repeats that breathing alone should not be considered of primary importance:
. . .I regret his [Spicer’s] employment of the term ‘Back Breathing’ . . . since I consider it dangerous as suggesting to the pupil that the act of breathing is of primary importance, and that he is to perform it with a particular part of his body. As a matter of fact, given the perfect co-ordination of all the parts as acquired by my system, breathing is a subordinate operation which will perform itself.
In the 1911 MSI Addenda, when discussing the act of walking, Alexander refers to ‘the primary movements of allowing the body to incline forward’:
The whole physiology of walking is, indeed, perfectly simple when once these fundamental principles are understood. It is really resolved into the primary movements of allowing the body to incline forward from the ankle on which the weight is supported and then preventing oneself from falling by allowing the weight to be taken in turn by the foot which has been advanced.
This description was included in the 1918 MSI. This suggests that primary movement is not a specific movement, but is relative to what act is to be performed.
The last occurrence of primary movement is in CCC:
Co-ordinated use of the different parts during any evolution calls for the continuous, conscious projection of orders to the different parts involved, the primary order concerned with the guidance and control of the primary part of the act being continued whilst the orders connected with the secondary part of the movement are projected, and so on, however many orders are required (the number of these depending upon the demands of the processes concerned with a particular movement). Ordinarily, in attempts to use two or more parts in remedial work, the primary projection ends with the correct or incorrect use of the parts concerned with the primary movement.
From the above it would appear that ‘primary movement’ is best viewed in the context of the activity undertaken and in the context of conscious preparations such as mental attitude and orders (primary orders, secondary orders, etc.).
It is evident that Alexander was grappling with defining what is primary in importance and in time in any activity. This issue was resolved with the concept of the primary control where primary orders, motive power and movement (the first act now being the head going forward and up and the back lengthening and widening) may be said to be subsumed into a more comprehensive concept. Primary control first appears in 1925, after which there are no further references to primary movement. (However, there are still references to other concepts being primary, e.g. ‘primary direction’, ‘primary act’ in UoS.) See also Primary control.
Walter Carrington made several references to ‘primary movement’.    In Explaining the Alexander Technique Carrington considers ‘the true primary movement in each and every act’ (in ‘The Theory and Practice of a New Method of Respiratory Re-Education’ in MSI) as the ‘head has to go up’. Carrington agrees with the interviewer that the primary control is a later version of the primary movement.
Edward Maisel suggests that ‘primary movement’ refers to the ‘greatest lengthening of the spine possible in whatever we may be doing’.
Jeroen Staring suggests that ‘primary movement’ only refers to the ‘proper breathing-related movements’ in ‘Frederick Matthias Alexander, Born 150 Years Ago, on January 20, 1869. A Fierce Comment Regarding Interpretations of Alexander’s Texts by Alexander Technique Teachers’.
Bob Lada in ‘Teaching Alexander from “Yes”’ writes that he prefers the term ‘primary movement’ or ‘primary coordination’ to ‘primary control’.
Malcolm Williamson in ‘How did the concept of primary control evolve during Alexander's lifetime?’ takes the view that a wider reading of Alexander’s books suggests that the ‘true primary movement’ refers to overall use and functioning, in each and every act.
Halvard Heggdal suggests that ‘primary movement’ only means ‘thoracic movement in breathing’ in his blog ‘The primary movement’.