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The current study aimed to determine the effect of an 11-week sprint resisted swimming training programme on the swimming performance and the orientation angles of the hand. Fourteen young female swimmers were divided into two equivalent groups and were trained with specific sprint training sets. The experimental group performed these sets using a swimming parachute. For the evaluation of the intervention, before and at the end of the 11 weeks period both groups performed 50 m front crawl with maximal intensity and their underwater motion was recorded using four cameras. Their underwater movements were manually digitised using the Ariel Performance Analysis System and the statistical treatment of the data revealed a significant increase of the mean swimming velocity (3.76 ± 0.04 %) and stroke rate (3.09 ± 0.08 %) only in the experimental group. Moreover, a significant reduction of the total stroke duration (-4.26 ± 0.09 %) and the relative duration of the non-propulsive phases (-12.70 ± 0.23 %) was also observed only in the experimental group. The resultant velocity of the hand, and the pitch and sweepback angles of the hand remained unaffected in both groups during the pull and push phases. However, a significant decrease of the pitch angle (-47.44 ± 3.37 %) during the entry & catch phase was observed only in the experimental group. The increased performance and the higher mean swimming velocity after the current sprint resisted training programme was mainly due to the temporal modifications of the stroke, along with the pitch angle reduction during the entry & catch phase., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The purpose was to assess the effect of an 11-week resisted swim training program using a water parachute on the inter-arm coordination in front crawl swimming. Fourteen female swimmers were divided into a control and an experimental group, and followed the same training program, except for the use of a water parachute by the experimental group in specific sprint sets. Before and after the intervention, the underwater motion of the swimmers was recorded using four camcorders and the digitisation process was undertaken manually. The two-way repeated measures analyses of variance revealed a significant increase of the swimming velocity, due to a significant increased stroke rate, because of the significant reduction of the total stroke duration, only in the experimental group. Moreover, their absolute and relative duration of the propulsive pull and push phases increased significantly, while the absolute and relative duration of their non-propulsive entry & catch and recovery phases decreased significantly. These modifications caused a significant increase in the index of coordination. Thus, this 11-week sprint resisted intervention program seems to improve the propulsion continuity and could be considered as an effective form of training, increasing the stroke rate and consequently the swimming velocity.

The aim of the current study was to compare the arm-stroke kinematics during maximal and sub-maximal breaststroke swimming using both discrete and continuous data analysis. Nine male breaststrokers swam 2 × 25 m with maximal and sub-maximal intensity and their full body 3-D kinematics were obtained using eight video cameras. The arm-stroke was divided into five phases: recovery, glide, out-sweep, in & down-sweep and in & up-sweep. The statistical treatment of selected discrete variables was conducted using t-test, while the analysis of their equivalent time series, when applicable, was conducted using Statistical Parametric Mapping. Sub-maximal trial, compared to maximal, presented lower swimming velocity, greater stroke length and less stroke rate. Moreover, the absolute and relative duration of the glide phase was longer, while the relative duration of all the other phases was shorter. The resultant hand velocity during the arm recovery was slower, as well as the hand velocity time series in the transverse and longitudinal axis which were slower from ∼ 45 % to ∼ 60 % and from ∼ 5 % to ∼ 15 % of the stroke cycle, respectively. Both discrete and continuous data analysis revealed that the main discriminating factor between the two conditions concerns to the adjustment of the glide and the recovery phase and consequently the continuation of the propulsive movements., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

This study investigated the effects of a 4-week training with hand paddles (HPD) on front-crawl swimming performance (SP), clean swimming speed (SPEED), stroke rate (SR), stroke length (SL) and tethered force (TF). Twenty swimmers (10 men and 10 women) were paired according to performance and gender, and were randomly assigned to control (CON, 22.4 ± 2.3 years) or HPD (21.8 ± 1.9 years) groups. During 4 weeks both groups performed the same training, except for a sprint training set (3 times/week, 10 × 10 strokes all-out, 1-min rest) completed with (HPD = 320 cm 2 ) and without (CON) paddles. Afterwards, both groups performed the same training over a 2-week taper period. SP, SPEED, SR, SL and TF were assessed before (PRE) and after the 4-week period (POST), after the first (T1) and second taper weeks (T2). Swimmers rated their perceived exertion for the sprint training set (RPE TS ) and the training session for determining internal training load (ITL). SP, SPEED, SR, SL and TF did not change from PRE to POST, T1 and T2. ITL and RPE TS were not different between groups. Training 4 weeks with HPD does not affect swimming performance, so the use of HPD remains unsupported in such period.

Gourgoulis, V, Valkoumas, I, Boli, A, Aggeloussis, N, and Antoniou, P. Effect of an 11-week in-water training program with increased resistance on the swimming performance and the basic kinematic characteristics of the front crawl stroke. J Strength Cond Res 33(1): 95-103, 2019-The purpose of the study was to assess the effect of an 11-week in-water training program with increased resistance on the swimming performance and the basic kinematic characteristics of the front crawl stroke in young female swimmers. Twelve swimmers were matched in pairs according to their best performance in 50-m front crawl swimming and then were randomly assigned to an experimental or to a control group. Both groups followed exactly the same swimming training program. The only exception was that the experimental group performed a sprint training section with increased resistance pulling a water parachute, whereas the control group performed the same section without parachute. Before and after the intervention program, the best performance of both groups in 50-, 100-, and 200-m front crawl swimming were assessed. Moreover, the basic kinematic characteristics of the stroke were calculated during 50-m front crawl swimming with maximal intensity. Two-way repeated measures analyses of variance revealed significant improvement in the best performance in all swimming distances only in the experimental group (3.22-7.26%). As far as the basic kinematic characteristics of the stroke are concerned, significant modifications were found only in the mean swimming velocity in the experimental group (2.18%), whereas no significant changes were observed in the stroke length, the stroke rate, and the duration of the propulsive, and nonpropulsive phases in both groups. Thus, the findings of the current study revealed a positive effect of the in-water resistance training program in the swimming performance of young female swimmers of moderate performance level, without any negative influence in the basic kinematic characteristics of the stroke.

Gourgoulis, V, Koulexidis, S, Gketzenis, P, and Tzouras, G. Intra-cyclic velocity variation of the center of mass and hip in breaststroke swimming with maximal intensity. J Strength Cond Res 32(3): 830-840, 2018-The aim of the study was to compare the center of mass (CM) and hip (HIP) intracyclic velocity variation in breaststroke swimming using 3-dimensional kinematic analysis. Nine male breaststrokes, of moderate performance level, swam 25-m breaststroke with maximal intensity, and their movements were recorded, both under and above the water surface, using 8 digital cameras. Their CM and HIP velocities and their intracyclic variations were estimated after manual digitization of 28 selected points on the body in a complete arm and leg breaststroke cycle. Paired sample t-tests or Wilcoxon tests, when the assumption of normality was broken, were used for statistical analyses. In both, CM and HIP velocity-time curves, the results revealed a similar pattern of 2 clear peaks associated with the leg and arm propulsive phases and 2 minimal velocities that corresponded to the arm and leg recovery phase and the lag time between the leg and arm propulsive phases, respectively. However, despite this similar general pattern, the HIP minimum resultant velocity was significantly lower, whereas its maximal value was significantly greater, than the corresponding CM values. Consequently, the HIP intracyclic swimming velocity fluctuation significantly overestimates the actual variation of the swimmer's velocity in breaststroke swimming.

The aim of this study was to assess the effect of the hand's acceleration on the propulsive forces and the relative contribution of the drag and lift on their resultant force in the separate phases of the front crawl underwater arm stroke. Ten female swimmers swam one trial of all-out 25-m front crawl. The underwater motion of each swimmer's right hand was recorded using four camcorders and four periscope systems. Anatomical landmarks were digitised, and the propulsive forces generated by the swimmer's hand were estimated from the kinematic data in conjunction with hydrodynamic coefficients. When the hand's acceleration was taken into account, the magnitude of the propulsive forces was greater, with the exception of the mean drag force during the final part of the underwater arm stroke. The mean drag force was greater than the mean lift force in the middle part, while the mean lift force was greater than the mean drag force in the final part of the underwater arm stroke. Thus, swimmers should accelerate their hands from the beginning of their backward motion, press the water with large pitch angles during the middle part and sweep with small pitch angles during the final part of their underwater arm stroke.

The aim of this study was to examine the influence of leg kick on the pattern, the orientation and the propulsive forces produced by the hand, the efficiency of the arm stroke, the trunk inclination, the inter-arm coordination and the intra-cyclic horizontal velocity variation of the hip in sprint front crawl swimming. Nine female swimmers swam two maximal trials of 25 m front crawl, with and without leg kick. Four camcorders were used to record the underwater movements. Using the legs, the mean swimming velocity increased significantly. On the contrary, the velocity and the orientation of the hand, the magnitude and the direction of the propulsive forces, as well as the Froude efficiency of the arm stroke were not modified. The hip intra-cyclic horizontal velocity variation was also not changed, while the index of coordination decreased significantly. A significant decrease (13%) was also observed in the inclination of the trunk. Thus, the positive effect of leg kick on the swimming speed, besides the obvious direct generation of propulsive forces from the legs, could probably be attributed to the reduction of the body's inclination, while the generation of the propulsive forces and the efficiency of the arm stroke seem not to be significantly affected.

Aim: The aim of the study was to assess the acute effect of front crawl sprint resisted swimming on the inter-arm coordination and the fluctuation of the swimming velocity., Methods: Nine female swimmers swam four all-out trials of 25 m, without and with low, moderate and high added resistance. Four camcorders were used to record the underwater movement. The inter-arm coordination was quantified using the index of coordination and the hip intra-cyclic velocity variation was analysed by calculating the coefficient of variation and the difference between the maximum and minimum velocities normalized for the mean stroke cycle velocity., Results: One-way repeated measures analyses of variance showed that swimmers change their inter-arm coordination from a "catch up" toward an "opposition" mode. Concerning the hip horizontal intra-cyclic velocity variation, it was increased significantly during resisted swimming., Conclusion: These findings indicate that although resisted swimming cause an increase in the index of coordination and consequently it could be speculated a better propulsive continuity, the velocity fluctuations of the hip within a stroke cycle are not decreased, probably due to the inability of the swimmers to overcome effectively the concrete added resistances used in this study. Thus, at least concerning its acute effect, the hypothesis that the sprint resisted swimming could led to a technical improvement can not be satisfied.

The purpose of the study was to examine the physiological responses, the stroke-parameter changes, and the ability to sustain a velocity corresponding to critical velocity (CV) during interval swimming on female swimmers of different age groups. Eight children (C; age: 10.4 ± 0.6 years), 11 young (Y; age: 13.1 ± 0.4 years), and 7 adults (A; age: 19.9 ± 4.6 years) swam all-out efforts of 50, 100, 200, 400 m for CV and critical stroke rate (CSR) calculation. Subsequently, the swimmers performed an interval training set of 5 × 300-m (C) and 5 × 400-m repetitions (Y and A) at a velocity corresponding to CV. The CV was higher in the Y and A compared with the C group (C: 0.962 ± 0.05, Y: 1.168 ± 0.09, A: 1.217 ± 0.05 m·s(-1), p < 0.05). The velocity of 5 × 300 and 5 × 400 m was not different compared with CV (C: 100 ± 2%, Y: 98 ± 3%, A: 98 ± 3% of CV, p > 0.05). The blood lactate concentration was similar between groups and was maintained steady within each group (C: 4.5 ± 1.4, Y: 4.9 ± 1.4, A: 3.9 ± 1.3 mmol·L(-1), p > 0.05). Heart rate was higher in the C and Y compared with the A group during the last 100 m of each repetition (p < 0.05). Stroke rate remained unchanged during the repetitions and was similar between groups and no different to the CSR (p > 0.05). Stroke length of the fifth repetition was 4.5 ± 4.0% shorter compared with the second repetition in the Y and 5.3 ± 2.0% shorter compared with the first repetition in the A group (p < 0.05). During the 28- to 31-minute duration intermittent swimming, children and young and adult female swimmers were able to sustain CV with a steady and similar blood lactate concentration. Decreased stroke length may indicate an earlier fatigue in young and adult swimmers.

Objectives: The purpose of this study was to examine the physiological responses on three interval training sets performed at intensities relative to the critical velocity which was calculated from two different combinations of distances using a 2-parameter linear model., Methods: In a controlled repeated measures design, ten male well trained swimmers (age: 15.2 ± 1.2 years) swam 5 × 400-m, 10 × 200-m and 20 × 100-m on separate days with rest to swimming ratio 1:8, aiming to maintain the critical velocity calculated from distances of 50, 100, 200, 400-m (CV(4)) or 200, 400-m (CV(200-400))., Results: The sustained velocity on the 5 × 400-m was lower compared to CV(4) and velocity on the 20 × 100-m was higher compared to CV(200-400). The velocity on the 10 × 200-m was kept similar to both CV(4) and CV(200-400) (5 × 400-m: 1.27 ± 0.07 vs. CV(4): 1.33 ± 0.09 ms(-1), p<0.05; 20 × 100-m: 1.32 ± 0.02 vs. CV(200-400): 1.28 ± 0.09 ms(-1), p < 0.05; 10 × 200-m: 1.30 ± 0.10 ms(-1) vs. CV(4) and CV(200-400), p > 0.05). The blood lactate concentration increased after 1200 compared to 400-m (4.45 ± 0.23 vs. 5.82 ± 0.24 mmol l(-1), p < 0.05) and was no different between sets (p > 0.05). Stroke rate and stroke length were not different between and within conditions (p>0.05). Heart rate during the recovery periods was lower in the 5 × 400-m compared to 10 × 200-m and 20 × 100-m training set (p < 0.05)., Conclusion: Interval swimming pace can be adjusted in relation to critical velocity calculated from distances of 200 and 400-m or from distance of 50, 100, 200, 400 m. When the distance of repetitions is increased from 100 to 200 and 400-m the velocity should be reduced by 2% to achieve similar metabolic responses., (Copyright © 2011 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

The aim of this study was to examine the acute effect of front crawl sprint resisted swimming with different added resistances on the kinematic characteristics of the stroke and the orientation of the hand. Ten female swimmers swam four maximal trials (25 m) with small, moderate, large, and no added resistance respectively. Four camcorders were used to record the underwater motion of the right hand and digitizing was undertaken using the Ariel Performance Analysis System. Stroke rate, the stroke length, and mean swimming velocity were significantly decreased, whereas the total duration of the stroke and the relative duration of the pull and push phases were significantly increased during resisted swimming. The increase in the total duration of the stroke was accompanied by an increase in absolute pull length, while no alterations were observed in relative pull length or medial-lateral displacements of the hand. Moreover, the mean resultant velocity of the hand, as well as the pitch and the sweepback angles of the hand were not modified. In conclusion, resisted swimming appears to be a specific form of training, at least regarding its acute effect, although long-term effects should be investigated further.

The purpose of the research was to determine the influence of hand paddles on the arm coordination in female front crawl swimmers. Ten female swimmers swam at a maximal intensity 25 m without, with small hand paddles (116 cm), and with large hand paddles (286 cm). Four S-VHS cameras were used to record the underwater motion of both arms, and the digitizing of selected points onto the subject's body was undertaken using the Ariel Performance Analysis System. The mean swimming velocity, the stroke length, the stroke rate, the relative duration of the separate phases of the stroke, and the index of coordination were then calculated. The index of coordination was defined as the time interval between the propulsive phases of the 2 arms expressed as a percentage of the mean duration of the stroke cycle. The results showed that when the hand paddles were worn, the mean swimming velocity (p < 0.05) and the stroke length (p < 0.05) were significantly increased, whereas the stroke rate was significantly decreased (p < 0.05). When large paddles were worn, the relative duration of the whole propulsive phase was significantly decreased (p < 0.05), and the relative duration of the nonpropulsive phase was significantly increased (p < 0.05). However, the index of coordination was remained unchanged under the 3 measurement conditions (p = 0.895). It was concluded that in front crawl hand-paddled swimming, significant increases of the swimming velocity was not caused by modifications in the pattern of arm coordination. Thus, hand-paddled swimming should not be used as a tool to alter the time sequence of the application of propulsive forces generated from the 2 arms.

The aim of this research was to study the effect of hand paddles on the pitch, the sweepback angles and other stroke kinematic characteristics of the hand during front crawl swimming. Ten female competitive swimmers swam without and with small (116 cm (2)) and large (268 cm (2)) paddles. Four cameras (60 Hz) were used to record the underwater strokes and the digitizing was undertaken using the Ariel Performance Analysis System. When the size of the paddles increased, the stroke length, the mean swimming velocity and the total duration of the stroke were significantly increased (p < 0.05), while the average velocity of the hand during the pull and the push phases were significantly decreased (p < 0.05). The stroke rate was decreased significantly (p < 0.05) only when using large paddles. The relative duration of the separate phases of the stroke, the magnitude of the medial-lateral displacements and the pitch and sweepback angles of the hand were not modified, indicating that the use of hand paddles did not caused significant alterations in the orientation and the movement of the hand during the underwater stroke in front crawl swimming.

Accuracy of kinematic data is of decisive importance in motion analysis particularly when they are to be used for the calculation of kinetic parameters, like the propulsive forces in swimming. The present study investigated the accuracy of underwater three-dimensional (3-D) kinematic analysis using periscope systems and calibration volumes with different size. Two analogue cameras (60Hz) were used to record the images, along with two stationary periscope systems for the underwater recordings. The calibration of the recording space was performed using two different-sized calibration frames. The reconstruction accuracy was determined in static and dynamic conditions, both under water and out of the water. In static conditions, the reconstruction accuracy was determined by calculating the root mean square (RMS) error for the reconstruction of eight validation points on the calibration frames, and in dynamic conditions it was determined by the percentage of RMS error of the reconstructed length of a moving rod. The results revealed that in static conditions the RMS error was greater during underwater analysis, due to refraction, and it was increased particularly in the longitudinal axis as the dimensions of the calibration volume were increased. The reconstruction errors observed during underwater recordings with both calibration volumes (transverse axis, 1.61-2.35mm; longitudinal, 2.99-4.64mm; vertical, 2.83-2.59mm) may be considered suitable for three-dimensional kinematic analysis of swimming.

The aim of the study was to investigate possible modifications caused by hand paddles in the relative contribution of the lift and drag forces of the hand and in the propelling efficiency, during front crawl swimming. Eight female swimmers swam 25 m with maximal intensity without paddles, with small (116 cm(2)) and with large paddles (268 cm(2)). Four cameras operating at 60 Hz were used to record the images and the Ariel Performance Analysis System was used for the digitisation. The results showed that, although during swimming with hand paddles the hand's velocity decreased, the greater propulsive area of the hand paddle caused an increase in the drag, lift, resultant and effective forces of the hand. However, the relative contribution of lift and drag forces on swimming propulsion was not modified, nor was the direction of the resultant force. Hand paddles also increased the propelling efficiency, the stroke length and the swimming velocity, mainly because of the larger propulsive areas of the hand in comparison with free swimming. However, the significant decrease of the stroke rate, might argue the effectiveness of hand paddle training, particularly when large paddles are used in front crawl swimming.

Aim: The purpose of the present study was to determine the effect of two different sized hand paddles on the three-dimensional underwater stroke pattern of front crawl swimming at a fixed stroke rate., Methods: Nine male adolescent competitive freestyle swimmers participated in the study. Each subject swam a series of 25 m trials at a constant stroke rate, without and with hand paddles of two different cross sectional areas (small paddles: 116 cm(2), large paddles: 311 cm(2)). An acoustic metronome connected with a sound amplifier was used to help the subject keep the stroke rate constant. Stroke rate was calculated for each subject using the time for 3 complete right arm stroke cycles. The underwater motion of each subject's right arm was filmed using two S-VHS cameras, operating at 60 fields/s, which were located behind two underwater viewing windows. The spatial coordinates of selected points on the right arm and the hip were calculated using the DLT procedure with 30 control points and after the digital filtering of the raw data with a cut-off frequency of 6 Hz, the hand's linear displacements and velocities, as well as the mean swimming velocity, were calculated. Moreover, the displacement of the hip in the direction of propulsion, from the right hand's entry to the next entry of the same hand, was calculated in order to determine the stroke length. For the statistical treatment of the data the analysis of variance for dependent samples was used., Results: The analysis of the data revealed that when hand paddles were worn, the stroke length (F(2,16)=10.329; P<0.05) and the mean swimming velocity (F(2),16=5.076; P<0.05) were significantly increased, while the temporal characteristics of the underwater stroke and the displacement of the hand were not significantly altered. On the other hand, the peak backward hand speeds during the insweep (F(2,16)=4.794; P<0.05) and the push phase (F(2,16)=5.827; P<0.05) were greatly reduced. These modifications were greater when large paddles were worn., Conclusions: From the results of the present study it was concluded that the movement pattern was not significantly modified when swimmers swam with hand paddles, at a constant stroke rate. However, large hand paddles caused a decrease in their hand velocities during the underwater stroke.