The short and explosive push-off needs a specific pattern of motor unit recruitment. Some mixture of slow twitch (to sustain skating posture) and fast twitch fibres (to effect push off) in the hip and knee extensors seems necessary for optimal skating performance.
Anthony Sargeant moved to the Netherlands in 1985 as Professor and Head of Department with a joint appointment in the University of Amsterdam and the Vrije University of Amsterdam. The passion for Speed skating was ubiquitous and he contributed some physiological insights into this research review which sought to describe the peculiar nature of this form of locomotion. Peculiar because paradoxically it crucially depends upon muscles not shortening doing work and generating muscle power but rather remaining in a fixed isometric contraction. It is the ability to sustain a low aerodynamic profile during the long glide element of the cycle which is the key to success. As the skater fatigues and can no longer maintain a low profile the body position rises and this leads to greater air-resistance and hence a slower speed in the long glide phase.
Journal of Sports Science
J Sports Sci. 1987 Winter;5(3):249-59