The energy cost of swimming and its determinants

Abstract

The energy expended to transport the body over a given distance (C, the energy cost) increases with speed both on land and in water. At any given speed, Cis lower on land (e.g. running or cycling) than in water (e.g. swimming or kayaking) and this difference can be easily understood when one considers that energy should be expended (among the others) to overcome resistive forces since these, at any given speed, are far larger in water (hydrodynamic resistance, drag) than on land (aerodynamic resistance). Another reason of the differences in Cbetween water and land locomotion is the lower capability to exert useful forces in water than on land (e.g. a lower propelling efficiency in the former case). These two parameters (drag and efficiency) not only can explain the differences in Cbetween land and water locomotion but can also explain the differences in Cwithin a given form of locomotion (swimming, which is the topic of this review): e.g. differences between strokes or between swimmers of different age, sex and technical level. In this review, the determinants of C(drag and efficiency, as well as energy expenditure in its aerobic and anaerobic components) will, thus, be described and discussed. In aquatic locomotion it is difficult to obtain quantitative measures of drag and efficiency and only a comprehensive (biophysical) approach could allow to understand which estimates are "reasonable" and which are not. Examples of these calculations are also reported and discussed.

Passive Drag in Young Swimmers: Effects of Body Composition, Morphology and Gliding Position

“…The swimmer's body position in water is affected by the buoyancy of body masses. During the streamline attitude, a typical position of swimming gliding, underwater torque force acts on the body and causes the legs to sink [10]. The body density has been demonstrated to affect the body torque and the literature agrees to assert that individual body density and morphology can impact the Dp [11].…”

The Influence of the Coaches’ Demographics on Young Swimmers’ Performance and Technical Determinants

“…where η F is the Froude efficiency (%), v the swim velocity (m•s −1 ), SF the stroke frequency (Hz), and l the shoulder to hand average distance (m) (Zamparo et al, 2020). The l was measured between the acromion and tip of the third finger, on dry land, whereas the swimmer was simulating a stroke cycle by digital photogrammetry (Morais et al, 2012).…”

Variation in competition performance, number of races, and age: Long-term athlete development in elite female swimmers

“…travelling [33] athletes may benefit from swimming more races in the competitions they are participating in, rather than increasing the number of competitions. Probably due to the high technical demand of swimming [34], physiological capacity and mental skills can be more readily transferred over various distances, compared to technical skills, which are more difficult to adapt between strokes [9]. Therefore, swimmers are trained for a specific swimming stroke rather than race distance [9].…”

“…This theory is hardly discussed among experts in the field [20,21,[39][40][41][42][43] and talent development most probably involves multiple factors [44]. Still, the high technical demand and specifics of in-water locomotion [9,34] may favour volume based training approaches and accumulated practice over time to achieve elite performance [45]. With the usual talent pathway, children start competitive swimming at the age of 8-10 [46].…”