Le Sacre du printemps is undoubtedly the work which opened a new era in pulse structure. When it was first performed in 1913, composers were already adopting irrational time units in some of their works: e.g. Tchaikovsky’s 5/4 movement in his Symphony no. 5, Holst in ‘Mars’ from The Planets Suite. Important as these innovations were, the rapid tempo of Stravinsky’s ‘Danse sacrale’ created a new dimension in pulse for music that was conducted. There was nothing new in the principle of irregular units being used in music. The rhythmic structure of Latin syllables in medieval plainchant sometimes fell into irregular stresses:

In the sixteenth century Claude Le Jeune was creatively involved in the experiments deployed by French poets and musicians of the Académie Française. One of his chansons was designed on the oscillation between subdivisions of two and three, creating a variable metre:

What was innovatory in Le Sacre du printemps was the requirement of the conductor to use rapid signals of irregular pulse, which a large orchestra had to respond to. It is puzzling that Monteux’s colossal achievement in conducting the premiere did not induce him to like the work.

In the ‘Glorification de l’élue’ and in the ‘Danse sacrale’ from Le Sacre du printemps the constant oscillation between beats of two and three subdivisions requires a technical solution. Relying on the fundamental principles discussed it is very important to avoid the ‘preparatory upbeat’ syndrome. Simply lift the arm as if taking a breath with the main pulse value in mind. Control of the flexible units is achieved by varying the height of the beat of the two pulse values. It is useful to practise by simply deploying only downbeats at first. The exercise is governed by beating the main units (.) while articulating the varying subdivisions of each beat verbally. Putting this into practise at Stravinsky’s metronome mark of i( = 144 in the ‘Glorification de l’élue’ it will be discovered that the dotted crotchet beat is considerably higher than the crotchet, and that the bouncing ball principle is especially noticeable as the dotted crotchet becomes much slower at the peak than that of the crotchet.