Peak performances in sport require the full deployment of all powers an athlete possesses. How factors like mechanical power output, technique, and drag each on itself, but also in concert determine swimming performance is subject of inquiry. This overview of swimming biomechanics focuses on three performance factors: (i) generation of propulsion in water, (ii) drag encountered by the body during swimming and (iii) propulsive efficiency. The theoretical considerations will be put to use by predicting individual power requirements for swimming a world record in the 50 m free style based on experimental data.

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The purpose of this study was to determine the effects of water temperature on rectal temperature and oxygen uptake during supine floating. Eight healthy males volunteered for this study. This study was performed in a supine position at rest on land and in three water conditions (25, 30 and 35 degrees Celsius). All experiments were performed for 35 minutes. Water conditions of immersion at 25 degrees Celsius resulted in a decrease in rectal temperature and an increase in oxygen uptake. The changes in rectal temperature differed among individuals. A significant correlation was observed between changes in rectal temperature and % body fat. However, the changes in rectal temperature were affected by other factors. These data suggest that the changes in rectal temperature during immersion at 25 degrees Celsius could be affected by other factors elaborated in this paper.

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This study aimed to examine a relationship between changing swimming direction and 25 m speed swimming. The changing swimming direction test was selected to measure coordination ability in water, and the 25 m speed swimming test to measure speed ability. The subjects were 36 competitive university swimmers including six water polo players. In both tests, they started by kicking the wall in the water. The intra-class correlation (ICC) between two trials was calculated to examine reliability. Pearson' s correlation coefficient was used to examine the relationship between both tests. Reliability in both tests was judged to be very high, because their ICCs were 0.98. Although both tests showed a significant, moderate correlation (r = 0.54), it was judged that their relationship is not very high because of a low degree of inter-contribution (under 30%). Factors other than swimming speed are considered to relate to the changing swimming direction test selected in this study. It is suggested that water polo players are excellent in changing swimming direction.

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This study aimed to determine a convenient method, applicable in a field setting, to evaluate starting technique for competitive swimmers. Five college swimmers volunteered as subjects for this study. This method calculated the swimming velocity at 50 cm intervals from video footage of the starting phase; that is from the start point to 15 m out. Reference points were marked on a course rope at 50 cm intervals. Video recording using a digital video camera (1/30 sec for a frame) was conducted traveling alongside the swimmer from the poolside. After the video recording, the time each reference point was passed and the swimming velocity for each 50 cm interval were calculated from the video footage. An autocorrelation coefficient was used to examine the intra-tester reliability of the passing time for each of the reference points calculated from the video footage, and the reproducibility of the starting performance of each swimmer. Autocorrelation coefficients for intra-tester reliability were high (0.79 to 0.98 with a lag of 0), as were those for reproducibility (0.84 to 0.93 with a lag of 0). The swimming velocity curve obtained using this method was considered to reflect the characteristics of the changes of swimming velocity caused by the swimmer's actions. Considering its convenience in a field setting, this study demonstrated the method's effectiveness.

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Recently, body height is considered as one of the major elements for synchronized swimmers to acquire high performance score. The aim of the study was to compare body height and proportion of Japanese female synchronized swimmers in elementary school to age-matched normal female Japanese or other Caucasian populations, by using charts of body height and proportion of girls in Japan. Subjects were nationwide synchronized swimmers of forth to sixth grade in elementary school, who participated in the audition for executing with the committee of synchronized swimming in Japan Swimming Federation. Body height and sitting height were measured for these athletes to evaluate body proportion. On the other hand, the data of girls in Japanese and Caucasian populations evaluated by the previous studies were used for comparison. As a result, body height and proportion in synchronized swimmers were similar and superior to those of general Japanese, respectively. However, those values were lower and inferior to those of general Caucasians, respectively. There were a limited number of Japanese athletes who had the comparable body shape to normal Caucasian.

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In this study, we propose the new technique to evaluate qualitatively the recovery motion of the arm in the crawl stroke which is the most fundamental swimming style. The recovery motion of the arm can be measured by the motion analysis using video camera. On the basis of the measuring result, the dynamic analysis is carried out using the 7-degree-of-freedom rigid body model on the upper limbs. By evaluating the load which affects the each arm joint from joint torque and joint force, and obtaining the power which shows the energy consumption of the joint, motion evaluation of some recovery actions is quantitatively carried out.
Our evaluation method will be useful for improvement of training and guidance methods in swimming.

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Supporting an event, water polo game analyses is executed by the scientific section of the Japanese Water Polo Committee, and the data is being offered to the athletes and the spectators at the venue. Moreover, the same data can be seen on a web site established for the game analyses. Also, statistical data of the games that aren't distributed at the venue has been uploaded to the web site.
The purpose of this study is to examine the utility value of the web site from the number of access hits and from a questionnaire survey.
1) The number of access hits increases rapidly from the first day of an event, and it continues to a high total until the statistical data is completely uploaded. Of course, depending on the event, there is a difference in the number of total access hits.
2) The web site user would prefer to see more detailed data rather than quickly uploaded data.
3) The web site user would like to see the uploading of game reviews and game broadcasts, in addition to the current contents.
4) It will be suggested to examine charging for the data sheets and the software for the game analysis in the future.

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At the World Swimming Championship Fukuoka 2001, which used a 3 meter depth pool, eight new world records were made in contrast to zero world records at the previous event which used a 2 m depth pool. Why the difference occurred was the motivation for this study. To determine whether “shallow water effect” occurs in a swimming pool, we measured the resistance of a life sized swimmer model in an experimental towing tank with three different water depths of 1.0, 2.0 and 3.5 meters.
The results were as follows;
1) When compared to 2.0 m depth condition, the resistance of towed model in the 1.0 m depth condition increased by 3.4 % at speed range 2 m/s and above. This can be recognized as “shallow water effect”.
2) Also compared to 2.0 m depth condition, the resistance in 3.5 m depth condition increased by 1.1 %. This may be regarded as a measurement error.
3) In conclusion, these experiments indicate that there is a “shallow water effect” in a swimming pool at a depth of about 1.0 m in the current competitive swimmers' speed range.

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We proposed a convenient method, applicable in a field setting, for evaluating starting techniques for competitive swimmers. This study aimed to examine whether a stopwatch is applicable in this evaluation method. Three procedures were used to measure the passing time at each reference point: (1) using a stopwatch (SW); (2) from video footage using the single frame step function in the video camera (VTR); (3) from video footage using a stopwatch (VTR+SW). Reference points were marked on a rope at 50 or 100 cm intervals in the starting phase; that is, from the start point to 15 m. Video recordings were made using a digital video camera (1/30 sec per frame), and video recordings and measurements of passing time using a stopwatch were conducted by traveling alongside the swimmer on the poolside. In both SW and VTR+SW, passing time could not be accurately measured at 50 cm intervals, while measurements at 100 cm intervals were possible with SW, but not VTR+SW. The autocorrelation coefficients between swimming velocity curves of the VTR and SW measurements at 100 cm intervals were 0.70 with a lag of 0 and 0.84 with a lag of 1, respectively. Thus, by using 100 cm intervals similar swimming velocity curves could be obtained using SW and VTR+SW. The swimming velocity curve calculated from 100 cm interval measurements provided an outline of starting techniques, although the amount of information decreased compared with the swimming velocity curve obtained with VTR at 50 cm intervals.

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