Elite Male Swimmers Research Articles

Effects of Exercise-Induced Muscles Damage on Regulation of Glucose Metabolism and Cytokines Regulation

This study was aimed to investigate the effects of exercise-induced muscle damage on the changes in blood glucose, serum insulin, creatine kinase (CK) and cytokines during five days post recovery period. Ten male elite swimmers of a school team were recruited as subjects in this study. All the subjects were under detraining for ten days, and the blood samples were collected before the single training as baseline levels. Subjects were asked to be trained under a designed program with an experienced trainer and the blood samples were collected after training and also one day, three days and five days after training. Blood glucose metabolism, bio-indicators such as CK, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were analyzed as the indexes in post recovery period. One-way ANOVA has been used to determine the significance between baseline and different recovery time periods. In the analysis of glucose metabolism test, fasting blood glucose, serum insulin, and HOMAIR which were seen as insulin resistance indexes were significantly higher (p＜.05) on the first day of the post recovery period. But the insulin resistance status was not continuously found in the third and fifth day after training. Meanwhile, the CK levels were truly higher (p＜.05) from the first day to the fifth day of recovery period. The pro-inflammatory cytokine IL-6 known as energy sensor in muscle was elevated significantly (p＜.05) from the first day to the end of the recovery period, and TNF-α was increased significantly (p＜.05) as IL-6 after single bout of high intensity training. These results conclude that acute intense training-induced muscle damage causes a short term of insulin resistance from exhausting of muscle glycogen. Monitoring of cytokines such as IL-6 and TNF-α could be biomarkers that indicated the recovery status of during the post training period. In the beginning of the muscle damage, high quality protein intakes should promote the muscle repairing, and then high carbohydrate consumption could help with glycogen replenish in the recovery period.

Oxygen Kinetics In A 200-m Front Crawl Maximal Swimming Effort

Oxygen uptake (VO2) assessment is of particular interest in training and performance diagnosis, as well as in swimming bioenergetics. However, studies of VO2 kinetics conducted in real swimming pool conditions are scarce mostly due to environmental and instrumental restrictions. PURPOSE: To describe the VO2 kinetics during a maximal 200m crawl effort, and to establish whether VO2peak is a good predictor of performance. METHODS: Seven crawl elite male swimmers (20.0±1.9 yrs, 76.4±6.0 kg and 185.6±6.2 cm) performed an all-out 200m crawl swim in a 25m pool. VO2 was measured using a telemetric portable gas analyzer connected to the swimmer by a low resistance respiratory snorkel and valve system. Gas exchange parameters were measured breath-by-breath and values averaged every 5 s. VO2 kinetics parameters were determined by nonlinear monoexponential fitting (the cardiodynamic phase was not considered). RESULTS: On-VO2 kinetics started by a sudden and exponential increase in VO2 at the onset of the effort. The mean value of the amplitude of VO2 fast component was 39.7±6.5 mL.kg-1.min-1. No on-VO2 slow component was observed. Figure 1 shows a sample VO2 curve, being observed that the swimmers were not able to maintain the higher values of VO2 till the end of the 200m effort. Off-VO2 kinetics showed the typical two-phase decrease in VO2. Mean VO2peak (70.3±5.6 mL·kg-1·min-1) was related with mean 200m velocity (1.43±0.03 m.s-1, r=0.90, p<0.01).Fig 1: On and off-VO2 kinetics of one swimmer during and after a 200-m maximal swim, being identified the amplitude, time delay and time constant of the fast component.CONCLUSION: Besides characterizing the VO2 on-kinetics of a 200m maximal swim, these results suggest that VO2peak is a good predictor of 200m crawl swimming performance, confirming the relevance of the aerobic contribution to energy demands in middle distance events. Supported by PTDC/DES/101224/2008.

Does Breathing Disturb Coordination in Butterfly?

This study quantified the effects of breathing compared to non-breathing and "race pace" on arm to leg coordination in the butterfly stroke. Twelve elite male swimmers swam at four paces: 400 m, 200 m, 100 m and 50 m. The arm and leg stroke phases were identified by video analysis to calculate the total time gap (TTG), which is the sum of T1 (hands' entry in the water/high point of first kick), T2 (beginning of the hands' backward movement/low point of first kick), T3 (hands' arrival in a vertical plane to the shoulders/high point of second kick) and T4 (hands' release from the water/low point of second kick). Two strokes with breathing were compared to two strokes with breath-holding. The TTG was greater with breathing (23.3% VS. 19%), showing less propulsive continuity between arm and leg actions (p<0.05). This was due to the shorter downward leg kick and longer arm catch and upward leg kick that led to longer glide time. Conversely, breathing leads to greater coupling between the hand exit and the end of leg propulsion, which was due to a shorter arm push phase to facilitate the head exit to breathe.

Associations of n-6 and n-3 polyunsaturated fatty acids and tocopherols with proxies of membrane stability and subcutaneous fat sites in male elite swimmers

We hypothesize that membrane stability of elite swimmers adapted to chronic intense training is dependent on polyunsaturated fatty acids (PUFAs) and tocopherols in blood pools and that the composition of PUFA in plasma nonesterified fatty acids (NEFAs) might be associated with specific subcutaneous fat sites. Our aims were to investigate in male elite swimmers the associations of n-6 and n-3 PUFA and alpha- and gamma-tocopherols with proxies of membrane stability (phase angle and erythrocyte osmotic fragility) and of PUFA in plasma NEFA with specific skinfolds. Brazilian male elite swimmers (n = 20) under regular training for an average of 4.1 h/d and 6.1 d/wk took part in the study. Blood samples were obtained once after 18-hour rest and an overnight fast. Fatty acids were determined in plasma NEFA and erythrocytes by gas chromatolography and tocopherols were determined in plasma and erythrocytes by high-performance liquid chromatography. The status of PUFA was assessed as mean melting point, PUFA index [(Sigman-6 + Sigman-3) / (Sigman-7 + Sigman-9)] and docosahexaenoic acid indices (22:5n-6/22:4n-6 and 22:6n-3/22:5n-6 ratios) calculated from erythrocyte fatty acids. Phase angle was associated with an index of docosahexaenoic acid inadequacy (22:5n-6/22:4n-6; r = -0.53, P = .019) and with 22:5n-3 in erythrocytes (r = 0.51, P = .024), and erythrocyte osmotic fragility was associated with plasma alpha-tocopherol (r = -0.51, P = .05), which is a biomarker of vitamin E status. Plasma NEFAs 18:3n-3 and 20:4n-6 were positively associated with skinfolds of the trunk and arms (r = 0.49-0.59, P = .011-.043). The data presented indicate that n-3 PUFA and vitamin E states possibly improve membrane stability in elite swimmers and that the extent of specific anatomic sites of subcutaneous adipose tissue in the upper body might contribute to the composition of NEFA in the resting state.

Modelling spatial–temporal and coordinative parameters in swimming

This study modelled the changes in spatial–temporal and coordinative parameters through race paces in the four swimming strokes. The arm and leg phases in simultaneous strokes (butterfly and breaststroke) and the inter-arm phases in alternating strokes (crawl and backstroke) were identified by video analysis to calculate the time gaps between propulsive phases. The relationships among velocity, stroke rate, stroke length and coordination were modelled by polynomial regression. Twelve elite male swimmers swam at four race paces. Quadratic regression modelled the changes in spatial–temporal and coordinative parameters with velocity increases for all four strokes. First, the quadratic regression between coordination and velocity showed changes common to all four strokes. Notably, the time gaps between the key points defining the beginning and end of the stroke phases decreased with increases in velocity, which led to decreases in glide times and increases in the continuity between propulsive phases. Conjointly, the quadratic regression among stroke rate, stroke length and velocity was similar to the changes in coordination, suggesting that these parameters may influence coordination. The main practical application for coaches and scientists is that ineffective time gaps can be distinguished from those that simply reflect an individual swimmer's profile by monitoring the glide times within a stroke cycle. In the case of ineffective time gaps, targeted training could improve the swimmer's management of glide time.

Arm coordination in elite backstroke swimmers

In this study, we assessed arm coordination in the backstroke over increasing speeds by adapting the index of coordination originally used in the front crawl. Fourteen elite male backstroke swimmers swam four trials of 25 m at the speeds corresponding to the 400-m, 200-m, 100-m, and 50-m events. The six phases of the arm stroke were identified by video analysis and then used to calculate the index of coordination, which corresponded to the time between the propulsive phases of the two arms. With increases in speed, the elite swimmers increased the stroke rate, the relative duration of their arm pull, and their index of coordination, and decreased the distance per stroke (P < 0.05). Arm coordination was always in catch-up (index of coordination of −12.9%) because the alternating body-roll and the small shoulder flexibility did not allow the opposition or superposition coordination seen in the front crawl. This new method also quantified the relative duration of the hand's lag time at the thigh, which did not change (∼2%) with increasing speed for the elite swimmers. The index of coordination enables coaches to assess mistakes in backstroke coordination, particularly in the hand's lag time at the thigh.

Comparison of the carnosine and taurine contents of vastus lateralis of elderly Korean males, with impaired glucose tolerance, and young elite Korean swimmers

The carnosine and taurine contents of the vastus lateralis of two diverse groups of Korean male subjects (elderly and impaired glucose-tolerant (IGT) subjects and young elite swimmers at a national sport university) having a similar national diet, were examined. Despite marked differences in age, fitness and clinical status the two groups showed almost identical muscle carnosine and taurine contents. In the case of carnosine, the results suggest a similar contribution to intracellular buffering capacity in the two groups of subjects, with no evidence of a reduction of this in elderly IGT subjects. In addition, both groups showed the same inverse relationship between the muscle carnosine and taurine contents; the spread of values between subjects, within-groups, most likely reflect variations in the type I (low carnosine, high taurine) or type II (high carnosine, low taurine) composition of the vastus lateralis. The relationship is consistent with a role of taurine in osmoregulation, compensating for variations between fibre types in the carnosine content.

Effects of Sodium Bicarbonate, Caffeine, and Their Combination on Repeated 200-m Freestyle Performance

The purpose of this study was to investigate the effects of sodium bicarbonate (NaHCO(3)), caffeine, and their combination on repeated 200-m freestyle performance. Six elite male freestyle swimmers ingested NaHCO(3) (0.3 g/kg; B), caffeine (6.2 +/- 0.3 mg/kg; C), a combination of both (B+C), and placebo (P) on 4 separate occasions before completing 2 maximal 200-m freestyle time trials (TT1 and TT2) separated by 30 min. No significant differences (p = .06) were observed for performance in TT1 (B 2:03.01 +/- 0:03.68 min, C 2:02.42 +/- 0:03.17 min, B+C 2:01.69 +/- 0:03.19 min, P 2:03.77 +/- 0:03.21 min) or TT2 (B 2:02.62 +/- 0:04.16 min, C 2:03.90 +/- 0:03.58 min, B+C 2:01.70 +/- 0:02.84 min, P 2:04.22 +/- 0:03.75 min). The drop-off in performance time from TT1 to TT2, however, was significantly greater when C was ingested than with B (-1.5%, p = .002) or B+C (-1.2%, p = .024). This is likely because of the lower blood pH and slower recovery of blood HCO(3) post-TT1 after C ingestion. These findings suggest that the ergogenic benefit of taking C alone for repeated 200-m swimming performance appears limited. When combined with NaHCO(3), however, its negative impact on repeated maximal exercise performance is reversed.

The critical velocity in swimming

In supra-maximal exercise to exhaustion, the critical velocity (cv) is conventionally calculated from the slope of the distance (d) versus time (t) relationship: d = I + St. I is assumed to be the distance covered at the expense of the anaerobic capacity, S the speed maintained on the basis of the subject's maximal O(2) uptake (VO2max) This approach is based on two assumptions: (1) the energy cost of locomotion per unit distance (C) is constant and (2) VO2max is attained at the onset of exercise. Here we show that cv and the anaerobic distance (d (anaer)) can be calculated also in swimming, where C increases with the velocity, provided that VO2max its on-response, and the C versus v relationship are known. d (anaer) and cv were calculated from published data on maximal swims for the four strokes over 45.7, 91.4 and 182.9 m, on 20 elite male swimmers (18.9 +/- 0.9 years, 75.9 +/- 6.4 kg), whose VO2max and C versus speed relationship were determined, and compared to I and S obtained from the conventional approach. cv was lower than S (4, 16, 7 and 11% in butterfly, backstroke, breaststroke and front crawl) and I (=11.6 m on average in the four strokes) was lower than d (anaer). The latter increased with the distance: average, for all strokes: 38.1, 60.6 and 81.3 m over 45.7, 91.4 and 182.9 m. It is concluded that the d versus t relationship should be utilised with some caution when evaluating performance in swimmers.

Sodium Bicarbonate Supplementation Improves 200 m Freestyle Performance in Elite Male Swimmers

Sodium Bicarbonate Supplementation Improves 200 m Freestyle Performance in Elite Male Swimmers

Monitoring Changes in Lean Mass of Elite Male and Female Swimmers

To characterize within-subject changes in anthropometric characteristics of elite swimmers within and between seasons. The subjects were 77 elite swimmers (31 females, 46 males, age 15 to 30 years) monitored over 0.4 to 9.2 years. One anthropometrist recorded their body mass (M) and sum of 7 skinfold thicknesses (S) on 2042 occasions over 14 years from phase to phase within a season and over consecutive seasons. We estimated change in lean mass using a newly derived index (LMI) that tracked changes in M controlled for changes in S. The LMI is M/Sx, where x = 0.16 +/- 0.04 for females and 0.15 +/- 0.05 for males (mean +/- SD). The LMI of males increased 1.1% (95% confidence limits +/- 0.2%) between preseason and taper phases, almost twice as much as that of females (0.6% +/- 0.3%). During the same period, M and S fell by approximately 1% and approximately 11%, respectively. From season to season LMI increased by 0.9% (0.8% to 1.0%) for males and 0.5% (0.3% to 0.7%) for females. All these within-subject effects on LMI were well defined (+/-approximately 0.3%). The typical variation (SD) of an individual's LMI was 1.2% for assessments within a season and 1.9% between seasons, with a short-term technical error of measurement of approximately 0.5%. Coaches and conditioners should typically expect a twofold greater increase in lean mass in male swimmers within and between seasons than in females. An LMI of the form M/Sx should be useful for monitoring individual swimmers and athletes in other sports in which body composition affects performance.

Cardiovascular Responses to Swimming

The authors examined cardiovascular responses to long-distance fin swimming as compared to freestyle swimming. Elite male fin swimmers (n = 17) swam 8 km in the open sea (group A) and 17 top freestyle endurance swimmers (group B) swam 6 km in the open sea. The swimming times of the 2 groups did not differ significantly. The heart rate and mean blood pressure were higher in group B than in group A after exercise. As estimated from the systolic time intervals (STI), total electromechanical systole index (QS(2)I) and electrical systole index (QTI) increased and QT-QS(2) decreased in both types of swimming. These changes were more marked in fin swimmers. Moreover, the preejection period (PEPI) and the preejection period to left ventricular ejection time ratio (PEP/LVET) significantly decreased in both groups, while LVET remained constant in the 2 swimming events. Likewise, the amount of change in PEP/LVET was more pronounced in group A. Finally, only the QT-QS(2) changes were associated with performance efforts in both groups. Therefore, there are quantitative cardiovascular differences between these types of swimming that should be primarily attributed to the different muscle mass effort involved.

Arm to Leg Coordination in Elite Butterfly Swimmers

This study proposed the use of four time gaps to assess arm-to-leg coordination in the butterfly stroke at increasing race paces. Fourteen elite male swimmers swam at four velocities corresponding to the appropriate paces for, respectively, the 400-m, 200-m, 100-m, and 50-m events. The different stroke phases of the arm and leg were identified by video analysis and then used to calculate four time gaps (T1: time gap between entry of the hands in the water and the high break-even point of the first undulation; T2: time gap between the beginning of the hands' backward movement and the low break-even point of the first undulation; T3: time gap between the hands' arrival in a vertical plane to the shoulders and the high break-even point of the second undulation; T4: time gap between the hands' release from the water and the low break-even point of the second undulation), the values of which described the changing relationship of arm to leg movements over an entire stroke cycle. With increases in pace, elite swimmers increased the stroke rate, the relative duration of the arm pull, the recovery and the first downward movement of the legs, and decreased the stroke length, the relative duration of the arm catch phase and the body glide with arms forward (measured by T2), until continuity in the propulsive actions was achieved. Whatever the paces, the T1, T3, and T4 values were close to zero and revealed a high degree of synchronisation at key motor points of the arm and leg actions. This new method to assess butterfly coordination could facilitate learning and coaching by situating the place of the leg undulation in relation with the arm stroke.

Energy cost of swimming of elite long-distance swimmers

The aim of this study was: (1) to assess the energy cost of swimming (C(s), kJ km(-1)) in a group of male (n = 5) and female (n = 5) elite swimmers specialised in long-distance competitions; (2) to evaluate the possible effect of a 2-km trial on the absolute value of C(s). C(s) was assessed during three consecutive 400-m trials covered in a 50-m pool at increasing speeds (v1, v2, v3). After these experiments the subjects swam a 2-km trial at the 10-km race speed (v2km) after which the three 400-m trials were repeated at the same speed as before (v5 = v1, v6 = v2, v7 = v3). C(s) was calculated by dividing the net oxygen uptake at steady state VO2ss by the corresponding average speed (v, m s(-1)). VO2ss was estimated by using back extrapolation technique from breath-to-breath VO2 recorded during the first 30 s of recovery after each test. C(s) increased (from 0.69 kJ m(-1) to 1.27 kJ m(-1)) as a function of v (from 1.29 m s(-1) to 1.50 m s(-1)), its values being comparable to those measured in elite short distance swimmers at similar speeds. In both groups of subjects the speed maintained during the 2-km trial (v2km) was on the average only 1.2% faster than of v2 and v6 (P>0.05), whereas C(s) assessed at the end of the 2-km trial (v2km) turned out to be 21 +/- 26% larger than that assessed at v2 and v6 (P<0.05); the average stroke frequency (SF, cycles min(-1)) during the 2-km trial turned to be about 6% (P<0.05) faster than that assessed at v2 and v6. At v5, C(s) turned out to be 19 +/- 9% (P<0.05) and 22 +/- 27% (0.1 < P = 0.05) larger than at v1 in male and female subjects (respectively). SF was significantly faster (P<0.05, in male subjects) and the distance per stroke (Ds = v/SF) significantly shorter (P<0.05) in female subjects at v5 and v6 than at v1 and v2. These data suggest that the increase of C(s) found after the 2-km trial was likely related to a decrease in propelling efficiency, since the latter is related to the distance per stroke.

Breaststroke Skills In Male Elite Swimmers Detected By Means Of A Speed Meter

A speed meter was developed that can measure the moving velocity of a competitive swimmer. The athlete swims a distance of 25m pulling a fine wire line out from a reel. The wire passed over a generator that was interfaced with a computer so the speed and distance of the wire line movement could be converted into velocity in m/sec (Maglischo, 2003.). With the speed meter, changes in velocity during one or more stroke cycles could be measured and analyzed. PURPOSE The purpose of this study was to determine if the speed meter could be used for analysis and improvement of breaststroke swimming performance. METHODS The velocity curves were compared for five male competitive breaststroke swimmers (18 to 23 years of age). One swimmer was an international competitor, two others had reached the national but not international level, and the final two swimmers were members of a University collegiate team but had not reached national or international levels of achievement. RESULTS The velocity curves of the lower achieving swimmers were compared to those of the high achievers and the following differences were noted. At one point in each stroke cycle the minimum velocity slowed almost to 0 for the lower achieving subjects but did not decline as much for the international and national level swimmers. The peak velocity during the kick phase was greater for the high achieving swimmers (Jonckheere-Terpstra Test, p <0.001). CONCLUSION These results suggest that improvements in breaststroke performance were dependent upon increasing the minimum velocities within each stroke cycle and improving the peak velocity of the breaststroke kick.

Breaststroke Skills In Male Elite Swimmers Detected By Means Of A Speed Meter

A speed meter was developed that can measure the moving velocity of a competitive swimmer. The athlete swims a distance of 25m pulling a fine wire line out from a reel. The wire passed over a generator that was interfaced with a computer so the speed and distance of the wire line movement could be converted into velocity in m/sec (Maglischo, 2003.). With the speed meter, changes in velocity during one or more stroke cycles could be measured and analyzed. PURPOSE The purpose of this study was to determine if the speed meter could be used for analysis and improvement of breaststroke swimming performance. METHODS The velocity curves were compared for five male competitive breaststroke swimmers (18 to 23 years of age). One swimmer was an international competitor, two others had reached the national but not international level, and the final two swimmers were members of a University collegiate team but had not reached national or international levels of achievement. RESULTS The velocity curves of the lower achieving swimmers were compared to those of the high achievers and the following differences were noted. At one point in each stroke cycle the minimum velocity slowed almost to 0 for the lower achieving subjects but did not decline as much for the international and national level swimmers. The peak velocity during the kick phase was greater for the high achieving swimmers (Jonckheere-Terpstra Test, p <0.001). CONCLUSION These results suggest that improvements in breaststroke performance were dependent upon increasing the minimum velocities within each stroke cycle and improving the peak velocity of the breaststroke kick.

Plasma Glutamine Changes After High-Intensity Exercise in Elite Male Swimmers

The aim of this study was to establish the pattern and time course of plasma glutamine recovery after acute, high-intensity exercise in well-trained swimmers. In Study 1, elite male swimmers (n = 8) performed 15 × 100m swimming intervals (ITS) at 70% and 95% of maximal 100m freestyle time. Resting plasma glutamine levels were determined on a nonexercise control day (0% ITS). Venous blood samples were obtained prior to, immediately after, and 30, 60, 120, and 150 min postexercise. In Study 2, the 95% ITS was repeated in elite male swimmers (n = 8), while control subjects (n = 8) did not exercise, to test for any diurnal variation in plasma glutamine levels. Venous blood samples were obtained prior to and 2, 4, 6, and 8 h postexercise. In Study 1, no change was observed in plasma glutamine following the 0% (control) and 70% ITS, but following the 95% ITS glutamine decreased significantly (p < 0.01) over the recovery period. In Study 2, plasma glutamine again decreased over the recovery period in the swimmers, but no changes were observed in the controls. It was concluded that intensive swim training results in postexercise decreases in plasma glutamine levels. Because glutamine has been suggested as a marker of overtraining, a need to measure glutamine at standard times within training programs is indicated.

The Spatial-Temporal and Coordinative Structures in Elite Male 100-m Front Crawl Swimmers

This study analysed the spatial-temporal and coordinative structures in 12 elite male 100-m front crawl swimmers. Swim performance was analysed over each length of a 25-m pool divided into five zones of 5 m. Velocity (V), stroke rate (SR), and stroke length (SL) were calculated for each zone and each length. Four stroke phases were identified by video analysis and the Index of Coordination (IdC) was established. Three modes of coordination were identified: catch-up (IdC < 0), opposition (IdC = 0), and superposition (IdC > 0). The swimmers tended to reduce the decrease in V and SR over the course of the 100 m by maintaining a stable SL. In fact, these spatial-temporal values were stable during the time spent stroking and were higher or lower during the start, the turns (in and out), and the finish. Thus the spatial-temporal changes did not occur within the lengths, but between them. Conversely, the evolution in the IdC showed that the swimmers had to install the stroke at the beginning and only reached a stable coordination in the second part of the race. Moreover, the IdC increased throughout the different zones of each 25-m length, indicating changes in motor organisation, particularly increases in the push or pull phases. The IdC values corresponded to a superposition of the arms, linked to a six-beat leg kick. Achievement of an effective superposition coordination occurred by boosting the stroke just after the turn-out until the end of the length. Regarding the spatial-temporal and coordinative structures of a 100-m front crawl, great swimming skill was reflected by both high and stable data.

Effect of swimming velocity on arm coordination in the front crawl: a dynamic analysis

We examined the preferred mode of arm coordination in 14 elite male front-crawl swimmers. Each swimmer performed eight successive swim trials in which target velocity increased from the swimmer's usual 3000-m velocity to his maximal velocity. Actual swim velocity, stroke rate, stroke length and the different arm stroke phases were then calculated from video analysis. Arm coordination was quantified by an index of coordination based on the lag time between the propulsive phases of each arm. The index expressed the three coordination modes in the front crawl: opposition, catch-up and superposition. First, in line with the dynamic approach to movement coordination, the index of coordination could be considered as an order parameter that qualitatively captured arm coordination. Second, two coordination modes were observed: a catch-up pattern (index of coordination = −8.43%) consisting of a lag time between the propulsive phases of each arm, and a relative opposition pattern (index of coordination = 0.89%) in which the propulsive phase of one arm ended when the propulsive phase of the other arm began. An abrupt change in the coordination pattern occurred at the critical velocity of 1.8 m · s−1, which corresponded to the 100-m pace: the swimmers switched from catch-up to relative opposition. This change in coordination resulted in a reorganization of the arm phases: the duration of the entry and catch phase decreased, while the duration of the pull and push phases increased in relation to the whole stroke. Third, these changes were coupled to increased stroke rate and decreased stroke length, indicating that stroke rate, stroke length, the stroke rate/stroke length ratio, as well as velocity, could be considered as control parameters. The control parameters can be manipulated to facilitate the emergence of specific coordination modes, which is highly relevant to training and learning. By adjusting the control and order parameters within the context of a specific race distance, both coach and swimmer will be able to detect the best adapted pattern for a given race pace and follow how arm coordination changes over the course of training.

우수 중거리 경영선수들의 200m 전력 수영과 회복기 동안 생리학적 변인들의 변화

To determine whether the concentration of fatigue-associated metabolites will be determinant of degree of the fatigue in middle distance swimmers during maximal swimming exercise conditions, we measured heart rate (HR), and lactic acid(LA), ammonia(AM), phosphorus(PHs), uric acid(UA), pH and glucose(Glu) in blood. For this study we recruited elite male middle distance swimmers(n=6) who have been participated about 30 hrs/wk for their routine training programs, and all subjects performed 200M time-trial swimming at similar pace with their ever best records. The resting HR was 54.00±1.84 beat/min, and the HR increased immediately(PostEx-0) after 200M swimming (122.83±1.80/sec) and gradually decreased during 30 min recovery(PostEx-30). The LA was also increased at cessation of exercise, but it was reached a peak value(8.01±0.48mM) after 3-5 min exercise finished. It was not the same pattern shown between HR and plasma LA during recovery period. Blood pH, measured both in plasma and whole, was significantly decreased immediately after swimming, and somewhat(but not completely) recovered with 10 min recovery. Plasma AM was elevated with 200M maximal effort swimming, and significantly decreased(but not completely recovered) after 10min recovery. The pattern of changes in blood pH and plasma AM concentration were similar immediately after swimming and during 10 recovery(p.05). Unlike plasma AM and blood pH responses, UA was not notably changed following exercise, but it was increased at PostEx-10(9.57±1.14㎎/㎗). Plasma Glu was significantly increased(p.001) at the cessation of maximal effort of swimming but it was returned to resting values with 10 minutes recovery. The results of this study indicated that physiological profiles could be an efficient marker for monitoring the impact of training and competition performance in 200m elite swimmer.