生田 泰志

This study aimed to estimate the factors that cause differences in competition level based on the competition performance structure among university student decathletes in Japan. The results of factor analysis using the maximum likelihood method (Oblimin rotation), assuming a five-factor structure estimated from parallel analysis and the information criterion, revealed the following competitive performance structures: "running speed and body projection,” "running endurance,” "rotational throwing power,” "translational throwing power,” and "vertical leaping power.” Some of these were similar to the competitive performance structures of the world’s top athletes, but they were found to have a unique structure: two throwing powers. The analysis results using latent rank theory allowed us to evaluate them on a seven-point scale. The calculated item reference profile, difficulty index, and discrimination index for each rank indicated that shot put and 100 and 400 m performance formed the basis of decathlon performance. In addition, high jump and pole vault, which fall under the category of "vertical leaping power," retained high difficulty and discrimination and were revealed to affect the stage of achievement of overall performance in the decathlon.

The study aims to test three hypotheses: (a) the rotation of the upper trunk consists of roll, pitch and yaw of frequencies harmonic to the stroke frequency of the front crawl stroke, (b) the rotation of the upper trunk generates back-and-forth movements of the shoulders, which enhances the movements of the stroking arms, and (c) the angular velocities of roll, pitch and yaw are associated with hand propulsion (HP). Front crawl strokes performed by twenty male swimmers were measured with a motion capture system. The roll, pitch and yaw angles about the three orthogonal axes embedded in the upper trunk were determined as three sequential Cardan angles and their angular velocities were determined as the three respective components of the angular velocity. HP and the drag and lift components of HP (HPD and HPL) were estimated by the hand positions and the data from twelve pressure sensors attached on hands. The roll, pitch, and yaw angles were altered in frequencies harmonic to the stroke frequency during the front crawl stroke. Shoulders alternately moved back and forth due to the upper trunk rotation. In the pull phase the angular velocity of roll was correlated with HPL (r = -0.62, p = 0.004). Based on the back-and-forth movements of the shoulders and roll motion relative to a hand movement, the arm-stroke technique of the front crawl swimming was discussed in terms of increasing the hand velocity and HP.

高アミロース米の血糖上昇抑制効果に関する報告は複数あるが、日本人を対象とした報告は少ない。そこで、日本人を対象に、高アミロース米「越のかおり」米飯摂取後の血糖応答について検討した。また、加水量を増やし柔らかく炊き上げた高アミロース米飯を用意し、水分量の違いが血糖応答に与える影響についても検証した。試験は健常成人を対象とした二重盲検の無作為化クロスオーバー試験とし、糖質50gを含む3種の米飯(通常加水コシヒカリ、通常加水越のかおり、高加水越のかおり)を用いた。通常加水越のかおりは通常加水コシヒカリと比較し、食後の血糖上昇を有意に抑えた。一方、高加水越のかおりには血糖上昇抑制効果が認められなかった。越のかおりは食後血糖値の急激な上昇を抑えることから糖尿病食事療法等に有用である可能性が示唆されたが、食味と機能性のバランスを両立させた調理方法については更なる検証が必要である。(著者抄録)

The purpose of this study was to examine the difference in muscle activation pattern and co-contraction of the rectus and biceps femoris in flutter-kick swimming between competitive and recreational swimmers, to better understand the mechanism of repetitive kicking movements during swimming. Ten competitive and 10 recreational swimmers swam using flutter kicks at three different velocities (100%, 90%, and 80% of their maximal velocity) in a swimming flume. Surface electromyographic signals (EMG) were obtained from the rectus (RF) and biceps femoris (BF), and lower limb kinematic data were obtained at the same time. The beginning and ending of one kick cycle was defined as when the right lateral malleolus reached its highest position in the vertical axis. The offset timing of muscle activation of RF in the recreational swimmers was significantly later at all velocities than in the competitive swimmers (47-48% and 26-33% of kick time of one cycle for recreational and competitive swimmers, respectively), although the kinematic data and other activation timing of RF and BF did not differ between groups. A higher integrated EMG of RF during hip extension and knee extension induced a higher level of muscle co-contraction between RF and BF in the recreational swimmers. These results suggest that long-term competitive swimming training can induce an effective muscle activation pattern in the upper legs. (c) 2015 Elsevier B.V. All rights reserved.

The aim of this study was to examine whether the intracyclic velocity variation (IVV) was lower in elite swimmers than in beginner swimmers at various velocities, and whether differences may be related to arm coordination. Seven elite and nine beginner male swimmers swam front crawl at four different swimming velocities (maximal velocity, 75%, 85%, and 95% of maximal swimming velocity). The index of arm coordination (IDC) was calculated as the lag time between the propulsive phases of each arm. IVV was determined from the coefficient of variation of horizontal velocity within one stroke cycle. IVV for elite swimmers was significantly lower (26%) than that for beginner swimmers at all swimming velocities (p< 0.01, 7.28 1.25% vs. 9.80 1.70%, respectively). In contrast, the IDC was similar between elite and beginner swimmers. These data suggest that IVV is a strong predictor of the skill level for front crawl, and that elite swimmers have techniques to decrease IVV. However, the IDC does not contribute to IVV differences between elite and beginner swimmers.

The purposes of this study were as follows: 1) to classify competitive swimmers on the basis of their stroke rate (SR) and stroke length (SL) by applying a factor analysis and a cluster analysis, 2) to derive discriminant functions by applying a multiple discriminant analysis of the stroke characteristics, and 3) to compare the race patterns of groups classified according to the results of the cluster analysis. 94 male swimmers who had participated in 100-m freestyle events held at the All Japan Swimming Championship from 2000 to 2004 were selected as subjects. The average value of their swimming velocity, SR, and SL in four swimming phases (15-25 m, 25-45 m, 57.5-75 m, and 75-95 m) were measured from videos captured. The subjects were classified according to their SR and SL by applying a factor analysis and a cluster analysis. Results showed that the competitive swimmers could be classified into Type1-4. Type1 showed high values of SR throughout the race, Type2 showed high values of SR in the first half and high values of SL in the second half, Type3 showed high values of SL in the first half and high values of SR in the second half, and Type4 showed high values of SL throughout the race. Although there was no difference in swimming records among the four groups, each group had different race patterns. These results suggest that the knowledge of race patterns might be useful to swimmers or coaches for planning race strategies. (Jpn. J. Phys. Fitness Sports Med. 2010, 59 : 465 similar to 474)

本研究では1997年度の日本代表・背泳選手について1996年度と1997年度のレース分析結果の比較および1997年度の競技結果から求められたレース各局面の所要時間の推定値と実測値との比較を行うことにより,記録の変化とその要因についての検討およびレースの特徴を把握することを目的とした。レースの局面分類および実験システムは日本水泳連盟医・科学委員会による従来の競泳レース分析法に従った。対象は1997年度パンパシフィック選手権および1997年度に行われた日本選手権大会における100m背泳の決勝レースのデータを採用した。また野村が作成した競技記録によるレース局面所要時間の推定式の100m背泳の係数を採用し,1997年度の競技結果における各局面の推定所要時間を求めた。その結果,記録が向上した3選手および記録の低下した1選手について,所要時間の短縮された局面と延長された局面の両方が存在していたことが判明した。また記録が向上した女子2選手についてはストローク長の延長が認められ,男子1選手についてはストローク頻度の向上が認められた。さらに野村による推定式を用いることでレースの特徴を把握することが可能であることが示された。The purpose of this investigation was to compare the important factors which may affect the swimming performance in All Japan Swimming Championship in 1996 and 1997, and to know the characteristics of the race pattern with the estimation method by Nomura, which is able to calculate each phase time to be taken during the swimming race. The subjects who participated in All Japan Swimming Championship in 1996 and 1997 and selected in National team in 1997 were 5 back stroke swimmers. Swimming races were classified 4 phases included start phase, stroke phase, turn phase and finish phase, and were analyzed on the video-tapes recorder by 4 cameras during the 100m back stroke races. In the present study, we utilized the time required on each phase, stroke rate and stroke length on stroke phase. As regards, 3 swimmers who improved their performance and 1 swimmer who could not improve, they all tended to both shorten and lengthen the time required. Moreover, 2 swimmers (female) who improved the performance tended to have longer stroke length than that of 1996, and 1 swimmer (male) who also improved the performance tended to increase storoke rate in 1997. These results suggested that we not only evaluate the record swimmers achieve, but we also need to evaluate the factors of all phases during the race. In addition, we suggested that it is possible to comprehend the characteristics of race pattern utilizing the estimation method by Nomura.

本研究では,1996年度および1997年度日本選手権大会において,100m自由形に出場した一流選手を対象に競泳のレース分析による各パラメータから検討を行った。分析の結果,1996年度および1997年度ともに決勝進出者は予選失格者よりも,競技レベルにおいて有意に優れていることが明らかになり,年度間の比較では,男女ともに統計的な差異は認められなかった。また,100m自由形レースにおいて,ターン局面は競技力向上に有効な要因となることが示唆された。スタート1回制については,1996年度と比較して1997年度のスタート局面速度の低下がみられ,特に決勝進出者は顕著に影響していることが散見された。ストロークの特徴を表すパラメータであるストローク長およびストローク頻度は,高い負の相関関係があり,それらは従来の方法よりも細部に分類する必要性が示唆された。The purpose of this investigation was to analyze of races and stroke characteristics for the Japanese elite swimmers who had participated in 100-m freestyle event at the 1996 and 1997 All Japan swimming championship. The performance of 32 male and 32 female swimmers in the event were analyzed to determine 14 parameters and to compare within each year and between 1996 and 1997, to asses the relationships between these parameters. The results as follows; 1) The female and male finalist swimmers were superior more than preriminary swimmers in swimming performance. 2) A statistical significant difference was not admited both female and male swimmers in the comparison of swimming performance at the 1996 term and 1997 term. 3) It was suggested that maintaining the 25-45m and 75-95m of stroke phase velocity become the factor of swimming performance improvement. 4) It was able to be comfirmed that the turn phase was also important in the race of 100-m Freestyle. 5) Stroke length and stroke rate showed a high negative correlation in this study was suggested from the current method of race analysis. 6) The once start system had the influence, especially, the finalist was remarkable.

本研究は,1991年度から1993年度までの日本選手権水泳競技大会男子200mバタフライに出場した116名を対象に,日本水泳連盟医・科学委員会によるレース分析結果からストローク局面のデータを用いて,競技レベルとレースパターンの関係を明らかにし,レース内容とレース展開について比較検討することを目的とした。その結果、泳速度はストローク長に大きく依存することが判明した。また,泳速度の変化パターンはストローク頻度の変化パターンに大きく依存することが判明した。さらに,ストローク頻度の変化パターンは,第2ラップを低下させ,その後第4ラップまで向上させることが有効であることが示唆された。The purpose of this investigation was to determine the rece pattern in competitive swimming,and to compare the rece pattern with performance level.The subjects who participated in All Japan Swimming Championship in 1991,1992 and 1993 were 116 elite swimmers of 200m butterfly stroke for men.The subjects were classified into 3 groups which were A group,B group and H group.A group,B group and H group indicated the swimmers who participated in final races,consolation final reces and couldn't participate in final races,respectively.Swimming reces were analyzed on the Video-tapes recorder by 4 cameras during the 200m butterfly reces,and were classified 4 phases included start phase,stroke phase,turn phase and finish phase.In the present study,we utilized swimming velocity,stroko rate and stroke length on the stroke phase.The results were summarized as follows:1.Stroke length of A group was longer than that of B and H group.Therefore there is a tendency that high performance swimmers has a longer stroke length comparison to low performance swimmers.2.The changing pattern of swimming velocity was affected by that of stroke rate.3.Although the high performance swimmers had a tendency decreasing stroke rate from Ist lap to 2nd lap,they increased stroke rate after 2nd lap in order to maintain swimming velocity.