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1.
The aim of this study was to examine the effect of swimming speed on leg-to-arm coordination in competitive unilateral arm amputee front crawl swimmers. Thirteen well-trained swimmers were videotaped underwater during three 25-m front crawl trials (400 m, 100 m and 50 m pace). The number, duration and timing of leg kicks in relation to arm stroke phases were identified by video analysis. Within the group, a six-beat kick was predominantly used (n = 10) although some swimmers used a four-beat (n = 2) or eight-beat kick (n = 1). Swimming speed had no significant effect on the relative duration of arm stroke and leg kick phases. At all speeds, arm stroke phases were significantly different (P < 0.05) between the affected and unaffected sides. In contrast, the kicking phases of both legs were not different. Consequently, leg-to-arm coordination was asymmetrical. The instant when the leg kicks ended on the affected side corresponded with particular positions of the unaffected arm, but not with the same positions of the affected arm. In conclusion, the ability to dissociate the movements of the arms from the legs demonstrates that, because of their physical impairment, unilateral arm amputee swimmers functionally adapt their motor organisation to swim front crawl.  相似文献   

2.
Ballet training includes exercises of high and moderate intensities, which require breathing control for a good performance. This study describes the thoracoabdominal motion of professional dancers and compares the breathing patterns between professional dancers and non-dancers. Participants of this study were four male and four female (30.33 ± 4.64 years) professional dancers and four male and four female (22.75 ± 1.49 years) non-dancers. The participants executed two breathing manoeuvres while sitting motionless: quiet breathing (QB) and vital capacity (VC). The 3D coordinates of 32 retro-reflective markers positioned on the trunk were used to calculate the volume of the superior thorax, inferior thorax and abdomen. Principal component analysis was applied in the volume variation of each trunk compartment to search for dominant independent variables in a breathing motion pattern. The correlation coefficient was calculated to verify the coordination between the compartments during the breathing manoeuvres. A predominance of the superior thorax or abdomen movement was found in both groups. The professional ballet dancers have an efficient breathing pattern and maintain the same breathing pattern in QB and VC manoeuvres. On the other hand, the non-dancers group showed relevant changes of the breathing pattern to respond to a greater breathing effort, like in VC.  相似文献   

3.
Task-specific auditory training can improve sensorimotor processing times of the auditory reaction time (RT). The majority of competitive swimmers do not conduct habitual start training with the electronic horn used to commence a race. We examined the effect of four week dive training interventions on RT and block time (BT) of 10 male adolescent swimmers (age 14.0 ± 1.4 years): dive training with auditory components (speaker and electronic horn) (n = 5) and dive training without auditory components (n = 5). Auditory stimulus dive training significantly reduced swimming start RT, compared with dive training without auditory components (p < 0.01), with a group mean RT reduction of 13 ± 9 ms. Four of the five swimmers that received auditory stimulus training showed medium to large effect size reductions in RT (d = 0.74; 1.32; 1.40; 1.81). No significant changes to swimmers’ BTs were evident in either dive training intervention. The adolescent swimmers’ results were compared against six male elite swimmers (age 19.8 ± 1.0 years). The elite swimmers had significantly shorter BTs (p < 0.05) but no significant difference in RTs. Auditory stimulus dive training should be explored further as a mechanism for improving swimming start performance in elite swimmers who have pre-established optimal BTs.  相似文献   

4.
Exercise and treating hyperlipidaemia with statins are two integral components of the American Heart Association guidelines to reduce cardiovascular risk in adults. Since statins can cause myalgias and myopathies, they could affect the duration or intensity of an exercise regimen. To determine the impact of statin use in adult masters swimmers, a survey was distributed to examine the association between swimming performance and statin usage in adult swimmers (≥35 years). After excluding those with chronic diseases or taking drugs that reduce physical capacity, 749 swimmers (118 taking statins, 73 not taking statins to control elevated cholesterol and 558 controls) were included in a regression model to determine the factors significantly affecting the duration and intensity of swimming workouts. Age and gender were significantly (P ≤ 0.001) associated with the distance swam per 60 min. Younger, male swimmers completed more yards per 60-min workout. Use of statins was not significantly associated with yards swam per 60-min workout. Nor did statin usage affect the number of swim sessions per month or the length of swim session. Evidently, statins do not cause enough fatigue or pain in masters swimmers to require a decrease in the duration or intensity of workouts.  相似文献   

5.
The aim of this study was to examine the performance characteristics of male and female finalists in the 100-m distance at the 2016 European Championships in swimming (long-course-metre). The performances of all 64 (32-males and 32-females) were analysed (8 swimmers per event; Freestyle, Backstroke, Breaststroke and Butterfly). A set of start and turn parameters were analysed. In the start main outcome, male swimmers were faster in Butterfly (5.71 ± 0.14s) and females in Freestyle (6.68 ± 0.28s). In the turn main outcome, male and female swimmers were faster in Freestyle (males: 9.55 ± 0.13s; females: 10.78 ± 0.28s). A significant and strong stroke effect was noted in the start and turn main outcome, in both sexes. In the start plus the turn combined, males and females were faster in Freestyle (males: 15.40 ± 0.20s; females: 17.45 ± 0.54s). The start and the turn combined accounted almost one-third of the total race time in all events, and non-significant differences (p > 0.05) were noted across the four swim strokes. Once this research made evident the high relevance of start and turns, it is suggested that coaches and swimmers should dedicate an expressive portion of the training perfecting these actions.  相似文献   

6.
The present study aimed to examine how high- and low-speed swimmers organise biomechanical, energetic and coordinative factors throughout extreme intensity swim. Sixteen swimmers (eight high- and eight low-speed) performed, in free condition, 100-m front crawl at maximal intensity and 25, 50 and 75-m bouts (at same pace as the previous 100-m), and 100-m maximal front crawl on the measuring active drag system (MAD-system). A 3D dual-media optoelectronic system was used to assess speed, stroke frequency, stroke length, propelling efficiency and index of coordination (IdC), with power assessed by MAD-system and energy cost by quantifying oxygen consumption plus blood lactate. Both groups presented a similar profile in speed, power output, stroke frequency, stroke length, propelling efficiency and energy cost along the effort, while a distinct coordination profile was observed (F(3, 42) = 3.59, P = 0.04). Speed, power, stroke frequency and propelling efficiency (not significant, only a tendency) were higher in high-speed swimmers, while stroke length and energy cost were similar between groups. Performing at extreme intensity led better level swimmers to achieve superior speed due to higher power and propelling efficiency, with consequent ability to swim at higher stroke frequencies. This imposes specific constraints, resulting in a distinct IdC magnitude and profile between groups.  相似文献   

7.
The aim of this study was to propose a new force parameter, associated with swimmers’ technique and performance. Twelve swimmers performed five repetitions of 25 m sprint crawl and a tethered swimming test with maximal effort. The parameters calculated were: the mean swimming velocity for crawl sprint, the mean propulsive force of the tethered swimming test as well as an oscillation parameter calculated from force fluctuation. The oscillation parameter evaluates the force variation around the mean force during the tethered test as a measure of swimming technique. Two parameters showed significant correlations with swimming velocity: the mean force during the tethered swimming (r = 0.85) and the product of the mean force square root and the oscillation (r = 0.86). However, the intercept coefficient was significantly different from zero only for the mean force, suggesting that although the correlation coefficient of the parameters was similar, part of the mean velocity magnitude that was not associated with the mean force was associated with the product of the mean force square root and the oscillation. Thus, force fluctuation during tethered swimming can be used as a quantitative index of swimmers’ technique.  相似文献   

8.
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9.
Abstract

The purpose of this study was to examine the adequacy of “multi-age” classification systems in youth sports with a specific focus on the unisex multi-age-groupings used by USA Swimming. In addition, we offer an analytical rationale for the multi-age-groupings and potential alternatives. We examined the top 100 US swim performances for three years (2005, 2006, and 2007) for girls and boys in 15 age-groups (7 to 20 years and a singular group of 21 years and older). Data for each age and sex were pooled over the three years and means were calculated for each of seven competitive swim events. Swim times differed among each age up to the 14-year age-group in girls (F 14,30885 = 183.9, P < 0.01, Cohen's d = 1.19–3.72, large effect) and 16-year age-group in boys (F 14,30885 = 308.7, P < 0.01, Cohen's d = 0.81–3.64, large effect) for all events. Age-related differences in swim times continued later in boys than girls likely due to differences between the sexes in timing of growth and maturation. Because of the differences in swim performance in contemporary multi-age-groups, stratifying swimmers by a single age is the best means to ensure competitive fairness and equality, although there is no rationale for swimmers under the age of 8 years to compete in separate unisex competitive groups.  相似文献   

10.
Abstract

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.  相似文献   

11.
Abstract

Throughout adolescence, swimmers begin to carry out demanding endurance and high-intensity training sets, the effect of which on redox status is largely unknown. The aim of the present study was to investigate the effects of 2000-m continuous swimming and 6 × 50-m maximal swimming on the redox status of adolescent swimmers. Fifteen male and 15 female swimmers, aged 14–18 years, provided blood samples before, immediately after, 1 h after, and 24 h after each exercise for the determination of redox status parameters. Oxidative damage was short-lived and manifest as increases in 8-hydroxy-2?-deoxyguanosine (8-OHdG) 1 h after high-intensity exercise (39%, P < 0.001) and in malondialdehyde immediately after both exercises (65%, P < 0.001). Alterations in antioxidant parameters were sustained during recovery: reduced glutathione decreased 24 h post-exercise (11%, P = 0.001), uric acid increased gradually after high-intensity exercise (29%, P < 0.001) and bilirubin peaked 24 h post-exercise (29%, P < 0.001). Males had higher 8-OHdG (49%, P = 0.001) and uric acid (29%, P < 0.001) concentrations than females. However, females showed higher values of malondialdehyde than males immediately post-exercise (30%, P = 0.039), despite lower pre-exercise values. In conclusion, both endurance and high-intensity exercise perturbed the redox balance without inducing prolonged oxidative damage in trained adolescent male and female swimmers. These swimming training trials were not found to be detrimental to the redox homeostasis of adolescents.  相似文献   

12.
Abstract

The purpose of the study was to determine whether there are differences in kinematics between sprint and distance front crawl specialists when swimming at a distance pace using a six beat kick. Seven sprint and eight distance male specialists performed one maximum 400 m swim through a 6.75 m3 calibrated space recorded by six gen-locked cameras. The following variables were calculated: average swim velocity, stroke length, stroke frequency, upper limb and foot displacement, elbow angle, the shoulder and hip roll angle, duration of the stroke phases and time corresponding to particular events within the stroke cycle relative to hand entry. Differences between the groups were assessed by an independent t-test and effect size (d) calculations for each variable. The groups only differed significantly with respect to the average swim velocity, with the distance swimmers maintaining a greater velocity throughout the 400 m. However, effect sizes were moderate for elbow angle range during the pull phase (d = 0.78) and the total hip roll magnitude (d = 0.76). There was little evidence to suggest that sprint and distance swimmers using a six beat kick pattern differ in technique when swimming at a distance pace and therefore coaches should not encourage the development of different techniques between these groups.  相似文献   

13.
Abstract

The continuous execution of swimming techniques may cause muscle imbalances in shoulder rotators leading to injury. However, there is a lack of published research studies on this topic. The aim of this study was to analyze the influence of a competitive swim period on the shoulder rotator–cuff balance in young swimmers. A randomized controlled pretest–posttest design was used, with two measurements performed during the first macrocycle of the swimming season (baseline and 16 weeks). Twenty-seven young male swimmers (experimental group) and 22 male students who were not involved in swim training (control group) with the same characteristics were evaluated. Peak torque of shoulder internal and external rotators was assessed. Concentric action at 1.04 rad s?1 (3 repetitions) and 3.14 rad s?1 (20 repetitions) was measured using an isokinetic dynamometer (Biodex System 3). External/internal rotators strength ratios were also obtained. For both protocols, there were significant training effects on internal rotator strength and external/internal rotator ratios (p ≤ .05). This trend was the same for both shoulders. Within-group analysis showed significant changes from baseline to 16 weeks for internal rotators strength and unilateral ratios of the experimental group. Swimmers' internal rotator strength levels increased significantly. In contrast, a significant decrease of the unilateral ratios was observed. Findings suggest that a competitive swim macrocycle leads to an increase in muscular imbalances in the shoulder rotators of young competitive swimmers. Swimming coaches should consider implementing a compensatory strength-training program.  相似文献   

14.
Recent advances in miniaturized waterproof accelerometers have allowed their use as a tool in examining swim stroke characteristics (Ohgi et al. JPSE Int J 45:960–966, 2002; Sports Eng 6:113–123, 2003). A better use for this technology, however, might be to quantify characteristics of competitive swim training. The purpose of this study was thus to examine commercial accelerometers’ ability to track and quantify swim training variables common to all swim training programs: speed and distance. Swimmers (n = 43) were fitted with two accelerometer monitors on their right wrist and ankle. From this output, regression analyses were performed as a means to describe swim distance and speed. Ten additional swimmers (experimental group, n = 10) were then utilized to cross validate these equations as being useful to predict swim distance and speed. The results demonstrated a positive, significant relationship between activity counts and actual swim distance (r = 0.90, p < 0.05), actual swim speed (r = 0.80; p < 0.05), and cross validation confirmed the accuracy of the prediction equations. The findings of the present study suggest that commercial accelerometer-based activity monitors have the ability to quantify important characteristics of competitive swim training.  相似文献   

15.
The purpose of this study was to compare arm–leg coordination and kinematics during 100 m breaststroke in 26 (8 female; 18 male) specialist breaststroke swimmers. Laps were recorded using three 50-Hz underwater cameras. Heart rate and blood lactate were measured pre- and post-swim. Arm–leg coordination was defined using coordination phases describing continuity between recovery and propulsive phases of upper and lower limbs: coordination phase 1 (time between end of leg kick and start of the arm pull phases); and coordination phase 2 (time between end of arm pull and start of leg kick phases). Duration of stroke phases, coordination phases, swim velocity, stroke length (SL), stroke rate (SR) and stroke index (SI) were analysed during the last three strokes of each lap that were unaffected by turning or finishing. Significant changes in velocity, SI and SL (P < 0.05) were found between laps. Both sexes showed significant increase (P < 0.05) in heart rate and blood lactate pre- to post-swim. Males had significantly (P < 0.01) faster swim velocities resulting from longer SLs (P = 0.016) with no difference in SR (P = 0.064). Sex differences in kinematic parameters can be explained by anthropometric differences providing males with increased propelling efficiency.  相似文献   

16.
Pacing strategies of elite swimmers have been consistently characterised from the average lap velocities. In the present study, we examined the racing strategies of 200 m world class-level swimmers with regard to their underwater and surface lap components. The finals and semi-finals of the 200 m races at the 2013 World Swimming Championships (Barcelona, Spain) were analysed by an innovative image-processing system (InThePool® 2.0). Free swimming velocities of elite swimmers typically decreased throughout the 200 m race laps (?0.12 m · s–1, 95% CI ?0.11 to ?0.14 m · s–1, P = 0.001, η2 = 0.81), whereas underwater velocities, which were faster than free swimming, were not meaningfully affected by the race progress (0.02 m · s–1, ?0.01 to 0.04 m · s–1, P = 0.01, η2 = 0.04). When swimming underwater, elite swimmers typically travelled less distance (?0.66 m, ?0.83 to ?0.49 m, P = 0.001, η2 = 0.34) from the first to the third turn of the race, although underwater distances were maintained on the backstroke and butterfly races. These strategies allowed swimmers to maintain their average velocity in the last lap despite a decrease in the free swimming velocity. Elite coaches and swimmers are advised to model their racing strategies by considering both underwater and surface race components.  相似文献   

17.
The present study aimed to compare muscle coordination strategies of the upper and lower limb muscles between beginners and elite breaststroke swimmers. Surface electromyography (EMG) of eight muscles was recorded in 16 swimmers (8 elite, 8 beginners) during a 25 m swimming breaststroke at 100% of maximal effort. A decomposition algorithm was used to identify the muscle synergies that represent the temporal and spatial organisation of muscle coordination. Between-groups indices of similarity and lag times were calculated. Individual muscle patterns were moderately to highly similar between groups (between-group indices range: 0.61 to 0.84). Significant differences were found in terms of lag time for pectoralis major (P < 0.05), biceps brachii, rectus femoris and tibialis anterior (P < 0.01), indicating an earlier activation for these muscles in beginners compared to elites (range: ?13.2 to ?3.8% of the swimming cycle). Three muscle synergies were identified for both beginners and elites. Although their composition was similar between populations, the third synergy exhibited a high within-group variability. Moderate to high indices of similarity were found for the shape of synergy activation coefficients (range: 0.63 to 0.88) but there was a significant backward shift (?8.4% of the swimming cycle) in synergy #2 for beginners compared to elites. This time shift suggested differences in the global arm-to-leg coordination. These results indicate that the synergistic organisation of muscle coordination during breaststroke swimming is not profoundly affected by expertise. However, specific timing adjustments were observed between lower and upper limbs.  相似文献   

18.
The aim of this study was to investigate the effect of pre-induced inspiratory muscle fatigue (IMF) on race-paced swimming and acid-base status. Twenty-one collegiate swimmers performed two discontinuous 400-m race-paced swims on separate days, with (IMF trial) and without (control trial) pre-induced IMF. Swimming characteristics, inspiratory and expiratory mouth pressures, and blood parameters were recorded. IMF and expiratory muscle fatigue (P < 0.05) were evident after both trials and swimming time was slower (P < 0.05) from 150-m following IMF inducement. Pre-induced IMF increased pH before the swim (P < 0.01) and reduced bicarbonate (P < 0.05) and the pressure of carbon dioxide (PCO2) (P < 0.05). pH (P < 0.05), bicarbonate (P < 0.01) and PCO2 (P < 0.05) were lower during swimming in the IMF trial. Blood lactate was similar before both trials (P > 0.05) but was higher (P < 0.01) in the IMF trial after swimming. Pre-induced IMF induced respiratory alkalosis, reduced bicarbonate buffering capacity and slowed swimming speed. Pre-induced and propulsion-induced IMF reflected metabolic acidosis arising from dual role breathing and propulsion muscle fatigue.  相似文献   

19.
Pacing strategies have been investigated for elite-standard freestyle swimmers, but little is known about pacing in age-group freestyle swimmers. We investigated changes in swimming time across distances in 4,481 women and men swimmers who competed in 100, 200, 400, and 800 m freestyle age groups from 25–29 years to 90–94 years in the FINA World Masters Championships 2014. In 100 to 800 m, there was a small lap×sex interaction (P < 0.001, 0.033 ≤ η2 ≤ 0.045) whereby women had larger lap-to-lap changes in swimming time than men. From 100 to 800 m, there were moderate to large lap×age group interactions (P < 0.001, 0.054 ≤ η2 ≤ 0.235), i.e., pacing patterns differed by age groups. There were small main effects of lap on time in 100, 200, 400 and 800 m freestyle events (P < 0.001, 0.033 ≤ η2 ≤ 0.045). In summary, (i) the largest increase in swimming time occurred during the second lap and a decrease in time occurred during the last lap, except in the 100 m, and (ii) the effect of participants’ sex on lap time indicated larger percentage changes of pacing in women than in men. These findings should help coaches to develop age- and event-tailored pacing strategies.  相似文献   

20.
This study examined the validity of isometric strength tests for evidence-based classification in Para swimming. Thirty non-disabled participants and forty-two Para swimmers with physical impairment completed an isometric strength test battery designed to explain activity limitation in the freestyle discipline. Measures pertaining to dominant and non-dominant limb strength and symmetry were derived from four strength tests that were found to be reliable in a cohort of non-disabled participants (ICC = 0.85–0.97; CV = 6.4–9.1%). Para swimmers had lower scores in strength tests compared with non-disabled participants (d = 0.14–1.00) and the strength test battery successfully classified 95% of Para swimmers with physical impairment using random forest algorithm. Most of the strength measures had low to moderate correlations (r = 0.32 to 0.53; p ≤ 0.05) with maximal freestyle swim speed in Para swimmers. Although, fewer correlations were found when Para swimmers with hypertonia or impaired muscle power were analysed independently, highlighting the impairment-specific nature of activity limitation in Para swimming. Collectively, the strength test battery has utility in Para swimming classification to infer loss of strength in Para swimmers, guide minimum eligibility criteria, and to define the impact that strength impairment has on Para swimming performance.  相似文献   

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