The purpose of this study was to investigate the characteristics of racing pattern adopted by elite male speed skaters in official 5000m race. Twenty-four male skaters, who participated at the World Single Distances Speed Skating Championships 2008, were recorded using video camera (60Hz). The top group (top12 ranked skaters) was significantly faster than the 2nd group (13th to 24th ranked skaters) from 350m line to the finishing line (

Fujii, Norihisa

Takenaka, Shunsuke

Yuki, Masahiro

English

ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive

393ISBS 2011 Porto, PortugalVilas-Boas, Machado, Kim, Veloso (eds.) Biomechanics in Sports 29Portuguese Journal of Sport Sciences11 (Suppl. 2), 2011  THE ANALYSIS OF RACE PACING IN ELITE COMPETITIVE LONG-DISTANCE SPEED SKATING  Shunsuke Takenaka1, Masahiro Yuki2 and Norihisa Fujii3  Doctoral Program in Physical Education, Health and Sport Sciences,  University of Tsukuba, Tsukuba, Japan1 Faculty of Education, Shinshu University, Nagano, Japan2 Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan3   The purpose of this study was to investigate the characteristics of racing pattern adopted by elite male speed skaters in official 5000m race. Twenty-four male skaters, who participated at the World Single Distances Speed Skating Championships 2008, were recorded using video camera (60Hz). The top group (top12 ranked skaters) was significantly faster than the 2nd group (13th to 24th ranked skaters) from 350m line to the finishing line (p<0.001~0.05). The variations of speed in curve sectors were smaller for the top group than the 2nd group (Lap2nd & 8th, p<0.05), and also smaller in straight sectors (Lap8th & 9th, p<0.01~0.05). These results suggest that it is important to adopt a "positive pacing strategy" and to distribute skating speed evenly as possible within each lap, especially not to decrease skating speed excessively in straight sectors at that time.  KEY WORDS: ice skating, competition, racing pattern, strategy, 5000m.  INTRODUCTION: It is known that there are several pacing strategies, which affect the performance in Long-distance speed skating. According to the previous studies, almost of elite male skaters observed during the competitive 5000m races adopted a similar strategy by starting fast before pace gradually declined throughout the duration of the race (Yuda et al., 2002, Thomas et al., 2010). This pacing pattern is called ”positive pacing strategy”. However, little attention has been given to the difference in skating speed at each curve and straight sectors during the whole race. The present study aimed to investigate the characteristics of racing pattern adopted by elite male speed skaters in official 5000m race.   METHODS: Twenty-four elite male speed skaters, who participated at the World Single Distance Speed Skating Championships in 2007/2008 season, were videotaped with two video cameras (60Hz) during the whole course of the men’s 5000m race. They were divided into two groups according to the final standings, the top group (top12 ranked skaters) and the 2nd group (13th-24th ranked skaters). The average speed and skating cycle frequency for six sectors (included two curves and four straights) were calculated at each lap based on the temporal data collected by the timer counter superimposed on the video images. The rate of decline (%) in skating speed was defined as “(1 - (time of Lap1st to 6th) / (time of Lap7th to 12th)) ×100” (Yuki et al., 1999, Yuda et al., 2002). The unpaired t-test was used to assess the significant differences between two variables for the both groups. The level of significance was set at =0.05. Values are shown as mean ± SD.  RESULTS AND DISCUSSION: The mean total time of the top group was 6:29.93 ± 6.26 seconds (6:17.24 ~ 6:38.01) and that of the 2nd group was 6:43.80 ± 3.95 seconds (6:39.41 ~ 6:51.74) (p<0.001). Figure 1 shows the means skating speed at each sector during the whole race. The top group was significantly faster from 350m line to the finishing line than the 2nd group (p<0.001~0.05). The skaters of the both groups adopted a similar strategy by starting fast before pace gradually declined throughout the duration of the race so-called “positive pacing strategy”. These results were similar to previous studies (Yuda, et al.,2002, Thomas et al., 2010). The rate of decline in speed of the top group was significantly lower than the 2nd group (2.00 ± 1.98% vs. 3.88 ± 2.11%, p<0.05). The range of sector speeds at each lap of the top group were smaller than the 2nd group, and a significant difference was detected at Lap9th (p<0.001, Figure 2). All skaters accelerated in curve sectors and decelerated in 3rd Straight  to the left side. These results related to asymmetry are in accordance to Seifert et al (2005), whom noticed that the most of the front crawl adult swimmers adopted asymmetric arm coordination suggested that asymmetry may thus be a true coordination mode and not just a functional error (Tourny-Chollet et al, 2009). According to these authors (Seifert et al, 2005; Tourny-Chollet et al, 2009) this asymmetry could be as a result of the unilateral breathing usually reinforced by learning and training.  Regarding to the arm left and right phases, the difference between genders in left push phase could explain this asymmetry. This longer phase showed by boys lead them to exhibited slightly high values (although not statistical significant) of IdCright compared with girls. In this sense, boys try to maximize the strength of the right arm, which could be their dominant arm, to increase propulsion.  CONCLUSION: Only catch up mode was resisted in young swimmers when swimming front crawl at very high intensity. The observed lower relative duration of the propulsive phases was due to the higher time spent during the entry/catch phase. An asymmetry to the right side for boys and to the left side for girls were registered, which could be the result of the unilateral breathing usually reinforced by learning and training (as noticed before by Nikodelis et al., 2005 and Tourny-Chollet et al., 2009), but also due to the fact that young swimmers are in the middle of their maturational development.   REFERENCES: Chollet, D., Charlies, S. & Chatard, C. (2000). A New Index of Coordination for the Crawl Description and Usefulness. International Journal of Sports Medicine, 21, 54-59. Herzog, W., Nig, B.M., Read L.J., Olsson E. (1989). Asymmetries in ground reaction force patterns in normal human gait. Medicine Science Sports Exercice, 21, 110-114. Millet, G.P., Chollet, D., Chalies, S. & Chatard, J.C. (2002). Coordination in Front Crawl in Elite Triathletes and Elite Swimmers. International Journal of Sports Medicine, 23, 99-104. Nikodelis, T., Kollias, I., & Hatzitaki, V. (2005). Bilateral inter-arm coordination in Freestyle swimming: Effect of skill leveland swimming speed. Journal of Sports Science,  23, 737 – 745. Robinson, R. O., Herzog, W., & Nigg B. M. (1987). Use of force platsform variables to quantify the effects of chiropractic manipulation on gait symmetry. Journal Manipulation Physical Therapy, 10, 172-176. Schnitzler C., Seifert, L., Ernwein, V. & Chollet, D. (2007). Arm Coordination Adaptation Assessment in Swimming. International Journal of Sports Medicine, 28, 1-7. Seifert, L., Boulesteix, L. & Chollet, D. (2003). Effect of Gender on the Adaptation of Arm Coordination in Front Crawl. International Journal of Sports Medicine, 25, 217-223.  Seifert, L., Chollet, D. & Allard, P. (2005). Arm Coordination Symmetry and breathing effect in front crawl. Human Movement Science, 24, 234-256. Seifert, L., Chollet, D. & Bardy, B. G. (2003b). Effect of swimming velocity on arm coordination in the front crawl: a dynamic analysis. Journal of Sports Science, 22, 651-660. Seifert, L., Chollet, D. & Rouard, A. (2006). Swimming constraints and arm coordination. Human Movement Science, 26, 68-86. Tourny-Chollet, C., Seifert, L. & Chollet, D. (2009). Effect of Force Symmetry on Coordination in Crawl. International Journal of Sports Medicine, 30, 182-187. Vorontsov, A. (2010). Strength and Power Training in Swimming. Nova Science Publishers, Inc., 16, 1-31.    394ISBS 2011 Porto, PortugalVilas-Boas, Machado, Kim, Veloso (eds.) Biomechanics in Sports 29Portuguese Journal of Sport Sciences11 (Suppl. 2), 2011STRIDE REGULATION AT THE APPROACH PHASE OF LONG JUMP IN VISUALLY IMPAIRED (F13) ATHLETES  Apostolos Theodorou1, Skordilis Emmanouil1, Evagelos Tasoulas2, Flora Panteli1, Athanasia Smirniotou1 and Paradisis Georgios1   National and Kapodistrian University of Athens – TEFAA, Greece1 International Paralympic Committee, Greece2  The present work studied whether visually impaired (VI) class F13 long jumpers showed at the approach run the same pattern of variability in footfall placement across trials as their non-VI counterparts. The long jump finalists (men and women), of the IBSA 2009 European Athletics Championship were recorded. VI long jumpers demonstrated an initial ascending variability followed by a descending one suggesting some type of regulation. This control emerged on the 5th and 4th stride prior to take-off and at a mean distance of 8.8±1.9m and 8.3±2.6m from the take-off board for men and women respectively. TBD variability reached a maximum value of 30.0±18.9cm and 25.2± 14.4cm and was finally reduced to 7.73cm (± 6.65cm) and 8.2± 2.6cm for males and females respectively. The striding pattern observed was similar to that reported in the literature for non-VI athletes.   KEY WORDS: Long jump, stride regulation, visually impaired.  INTRODUCTION: The approach phase and the technical skill of placing the take-off foot on the board with accuracy, speed and right technique during a long jump constitutes a demanding task for the performer. The successful completion of this task depends heavily on the constancy of the run up distance, number of strides and the ability of the athlete to reach maximal controllable horizontal velocity in a similar fashion across all tries. Many studies using a vast range of performers (elite, high class, skilled, unskilled, novices) (Berg & Mark 2005; Berg, Wade & Greer, 1994; Bradshow 2005; Hay, 1988; Hay & Koh 1988; Scott, Li & Davids, 1997) suggested that the final fraction of the long jump’s run-up is visually regulated and that this regulation constitutes an ever-present element of the event’s performance.  Long jump is one of the events of the International Blind Sport Association (IBSA) and Paralympics competition programme and among the ones that attract a large number of high level competitors. Competing athletes are classified in three distinct categories according to their respective visual impairment (F11, F12 & F13). Visually impaired (VI) athletes participating in class F13 have visual acuity of above 2/60 up to visual acuity of 6/60 and/or visual field of more than 5 degrees and less than 20 degrees (IBSA 2009). Visual acuity of 2/60 or 6/60 means that the person cannot see, at a distance of 2 or 6 meters, the object which a person with normal eyesight would be able to see at 60 meters. The long jump event in this category (F13) is performed according to the relevant IAAF competition rules applied for non-VI impaired athletes (IBSA 2009). The assimilation between non VI and VI long jumping provided us with the reasoning for conducting the present study. The purpose of the present study was to report if class F13 VI long jumpers demonstrate step length regulation in the approach run as reported in main literature for their non VI counterparts.   METHODS: The four finalists of the men’s long jump and the six finalist of the women’s long jump (class F13), of the International Blind Sport Association (IBSA) 2009 European Athletics Championship were recorded during the competition. The set up of the experimental procedure was according to the protocols described by most of the visual regulation studies so far (Berg & Mark 2005; Berg, Wade & Greer, 1994; Bradshow 2005; Hay, 1988; Hay & Koh 1988; Scott, Li & Davids, 1997). Forty (40) 1.0 meter zones were established on the runway and were designated by white markers placed at 1m intervals on either side of the runway and parallel to its long axis. This was to enable calculation of the horizontal distance between the toe and take-off board (toe-board distance). The approach phase of each long jump was recorded using a high definition digital video camera (SONY HDR-SR10) operating   straight sectors. Figure 3 shows the variations of skating speed in curve and straight sector at each lap. The top group was smaller than the 2nd group in curve sectors (Lap2nd & 8th, p<0.05) and also in straight sectors (Lap8th , p<0.05; Lap9th, p<0.01). There were significant positive relationships between the variations of skating speed and the cycle frequency in curve sectors (Lap2nd, p<0.05), also in straight sectors (Lap5th, p<0.01; Lap9th to 11th, p<0.05).    Figure 1: Means skating speed at each sector during the 5000m race.    Figure 2:   Ranges of sector speed within each lap during the 5000m race. Figure 3:   Variations of skating speed in curve and straight sector at each lap.  CONCLUSION: These results suggest that it is important to adopt a "positive pacing strategy" and to distribute skating speed evenly as possible within each lap, especially not to decrease skating speed excessively in straight sectors at that time.  REFERENCES:  Thomas, M., Stefan, P. & Christian, S. (2010). Pacing pattern and speed skating performance in competitive long-distance events. Journal of Strength and Conditioning Research.  24(1), 114-119. Yuda, J., Yuki. M., Fujii, N. & Ae, M. (2002). Analysis of the race pace for elite long distance speed skaters in 5000m race. Japanese Journal of Sport and Exercise. 6(2), 116-124 (in Japanese). Yuki, M., Hirano, T., Morioka, Y. & Ae, M. (1999). Analysis of men’s 1000m race-pattern in 1993 world sprint speed skate championships. Japanese Journal of Sport and Exercise. 3(4), 270-276 (in Japanese).  Acknowledgement The data of this study were accumulated with the cooperation of the Japanese Olympic Committee and Coca-Cola (Japan) Co., Ltd. We sincerely express our gratitude to those people. 

THE ANALYSIS OF RACE PACING IN ELITE COMPETITIVE LONG-DISTANCE  SPEED SKATING

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THE ANALYSIS OF RACE PACING IN ELITE COMPETITIVE LONG-DISTANCE SPEED SKATING

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