Swimming performance: lateral thinking for better starts

In pool swimming, every aspect of performance needs to be optimized to achieve victory, particularly at more elite levels of competition. Obviously, swimming fitness, stroke technique, pacing and efficient turns are all essential for maximizing performance. However, relative to its duration, the start technique is particularly important. Depending on the race length, the starting phase of swim race is reported as contributing from 0.8% to 26.1% of the total event duration⁽¹⁾. Unsurprisingly therefore, the swim start – everything from the initial leap off the blocks, to the flight through the air, water entry and underwater glide – has come under a great deal of scrutiny for ways to make any of these elements more efficient in order to shave even tenths of a second off race times.

Analyzing water entry

One of the elements that has received particular attention in recent years is the technique of water entry – ie the angle, orientation and depth of water penetration following initial contact with the water surface. In a 2018 study, researchers compared two different commonly-used entry styles: the flat and the pike style⁽²⁾. The flat style has a quick entry into the water using a flatter body position and earlier stroking, whereas the pike style creates a smaller hole for water entry with less friction and higher velocity due to the influence of gravity. It found that there were pros and cons to both, but that what matter most for performance was the total flight distance through the air (more being better), which in turn depended or excellent impulse and power off the block.

Lateral thinking

When discussing water entry technique, it’s invariably the angle of entry (shallow or deeper) that is considered the key variable. Last year however, an international team of researchers from China and New Zealand proposed a radically different approach – a so-called ‘lateral entry’ technique⁽³⁾. In a conventional water entry, the vertical angle of entry varies but entry is always parallel to the water surface. However, in a lateral entry technique, the swimmer rotates his or her body during the process of leaving the start block so that the entry to the water can approach anything up to a 90-degree rotation (see figure 1). Seen from head on, the swimmer’s shoulders would not remain parallel to the water surface but instead be aligned at an angle anything up to right angles with the water surface!

Figure 1: Standard vs. lateral water entry