Biomechanics and Medicine in Swimming XI

Figure 3. SV and SR of respective strokes in each subjective effort.
Table 1 shows the SV and SR of both strokes for each grading level.
Significant interaction was apparent in SV, but no significant interaction
was found for SR. The second finding is that both strokes have the same
ratio of SR increase when stepping up the subjective effort, but not the
same ratio of SV increase. Results show that the degree of SV increase
by increasing SR in BR was less than in FC, which might be attributed
to technical characteristics: the difference between the alternate arm
stroke in FC and the simultaneous arms stroke in BR.
Table 1. SV and SR of both strokes for each grading level, in % of max
Effort(%) FC-SV(%) BR-SV(%) interaction FC-SR(%) BR-SR(%) interaction
70 89.3±4.8 93.5±4.2 74.4±5.8 76.6±9.1
80 93.7±3.6 96.3±2.9 84.2±6.3 85.5±6.4
90 97.5±2.4 98.8±1.8 92.2±3.3 93.3±4.5
100 100 100 p = 0.011 100 100 p = 0.821
Note. SV, swimming velocity; SR, stroke rate;
FC, front crawl stroke; BR, breaststroke
Figure 4 presents the respective contribution of stroke phases of the
whole stroke duration. The FC showed almost identical percentages for
the three phases. With an increase of the grading level in FC, Phase 1
tended to decrease (from 39.1% to 33.2%), although Phase 2 increased
(from 37.1% to 42.9%). The percentage of Phase 3 (about 24%) did not
change at each grading level. These results might be attributable to alternate
strokeing in FC. In contrast, BR showed an especially large Phase
1 and a small Phase 2. With an increased grading level in BR, Phase 1
(from 59.9% to 51.0%) tended to decrease greatly, although both Phase
2 (from 13.8% to 16.8%) and Phase 3 (from 26.3% to 32.2%) increased.
These results might explain why BR gets more propulsion from kicking
than from arm strokes with simultaneous arm and leg motion.
Figure 4. Ratio of the time of each stroke phase to the whole stroke
duration.
chaPter4.trainingandPerformance
conclusIon
In conclusion, increasing and decreasing the swimming velocity depends
mostly upon SR, not only in FC but also in BR. However, the degree
of SV increase by SR increase in BR is expected to be less than in FC.
These results suggest that changing the swim speed by changing the
subjective effort in a race or in training can be considered a change of
coordination (style).
reFerences
Goya, T., Nomura, T. & Sugiura, K. (2005). The relationship between
stroke motion and output intensity for velocity during 50 m crawl
swimming in female. The Japan Journal of Sport Methodology, 18(1),
75-83.
Goya, T., Nomura, T. & Matsui, A. (2008). The relationship between
stroke motion and output intensity for velocity during 50 m crawl
swimming in male. Journal of Training Science for Exercise and Sport,
20(1), 33-42.
Leblanc, H. Seifert, L. & Chollet, D. (2009). Arm-leg coordination in
recreational and competitive breaststroke swimmers. Journal of Science
and Medicine in Sport, 12, 352-356.
Takagi, H. Sugimoto, S Miyashita, M, Nomura, T. Wakayoshi, K. Okuno,
K. Ogita, F. Ikuta, Y. & Wilson, B. (2002). Arm and leg coordination
during breast stroke: Analysis of 9th Fina World Swimming
Championships, Fukuoka 2001. Biomechanics and Medicine in Swimming,
IX, 301-306.
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