COACHING
SWIMMING TECHNIQUE CONCEPTS BY ROD HAVRILUK , Ph.D.
MAXIMIZING SWIMMING VELOCITY (Part 3):
MINIMIZING THE ARM ENTRY PHASE TIME IN FREESTYLE AND BUTTERFLY
T
he previous article (SW June 2021) in this series showed that with an increase in swimming velocity, there was a decrease in the time duration of all four phases of the stroke cycle for all four strokes. However, even at the fastest velocity, there was still a substantial amount of non-propulsive time in every stroke cycle, as shown in the data from four studies (Fig. 1): butterfly (Chollet, Seifert, Boulesteix, Carter, 2006), backstroke (Chollet, Seifert & Carter, 2008), breaststroke (Leblanc, Seifert, Baudry & Chollet, 2005) and freestyle (Seifert, Chollet & Bardy, 2004). The non-propulsive time in a stroke cycle consists of the time for the entry phase and the recovery phase. This article presents strategies to minimize the entry phase time for freestyle and butterfly so that a swimmer can decrease stroke cycle time, increase stroke rate and increase swimming velocity. FREESTYLE ENTRY PHASE To swim fast, swimmers must minimize the entry phase time. However, even when sprinting, there is usually at least 2-tenths of a second of non-propulsive time before the arm begins to generate propulsion. The graph in Fig. 2 shows the consistency in the entry phase time for 10 groups of elite swimmers from eight studies (only the first author is listed: Chollet, 2000; Guignard, 2020; Millet, 2002; Potdevin, 2006; Seifert, 2003, 2004; Schnitzler, 2008, 2010). The non-propulsive time on the arm entry is primarily due to the time required to move the arm from the position when it submerges to the position when it begins to generate propulsion. Research shows that when sprinting, male swimmers typically complete the arm entry parallel to the surface with the hand level with the shoulder, as shown by the male position in Fig. 3 (Havriluk, 2014). Female swimmers typically complete the entry with the hand above the shoulder, as shown by the female position. With either a typical male or female arm entry, time is required for a swimmer to move the arm below the shoulder to a position where propulsion can begin (i.e., the optimal position). If, instead, the arm submerged below the shoulder to the optimal position as it entered, the entry phase time would be minimized.
FIG. 1 >The graph shows the time duration of propulsive and non-propulsive phases of the stroke cycle for all four strokes.
FIG. 2 > The graph shows the entry phase time for swimmers from eight studies. The letters above the bars indicate the sex of the study participants (M = males, F = females, MF = males and females).
BUTTERFLY ENTRY PHASE Similar to freestyle, there is usually considerable excess time in the butterfly arm entry phase. For example, a typical butterfly arm entry for an elite swimmer is shown in the left image of Fig. 4. 20
JULY 2021
SWIMMINGWORLD.COM
The swimmer’s hands are just below the surface, and her shoulders are submerged far below her hands. She required almost 2-tenths of a second of entry phase time to submerge her hands below her shoulders to a position where she could begin to generate propulsion, as shown in the right image. The butterfly entry phase time was evaluated in a study of 23 university female swimmers (Becker & Havriluk, 2010). The group
