Crawl Swimming Research Articles

Scapulohumeral kinematics and neuromuscular control during scaption are associated with passive stiffness and strength of periscapular muscles in competitive adolescent swimmers

The passive stiffness and strength of periscapular muscles may affect scapulohumeral control, especially in overhead athletes due to sports-specific training. This study tried to assess the relationship between the passive stiffness and strength of periscapular muscles, scapulohumeral kinematics and neuromuscular control during scaption in swimmers. Ten male adolescent competitive front-crawl swimmers were recruited. The passive stiffness and strength of periscapular muscles were measured in standard postures by a hand-held myotonometer and dynamometer, respectively. Surface electromyography and electromagnetic tracking systems were synchronized to record the muscle activities and scapulohumeral kinematics during scaption. Correlations between the passive stiffness or strength of periscapular muscles and the kinematics or muscle activity were examined by Spearman's rank correlation coefficient. The maximal strength of periscapular muscles correlated positively with the ranges of upward and external rotation of the scapula and negatively with muscle activity during scaption. Passive stiffness of periscapular muscles was associated with the downward rotation of the scapula and triggered an increase in muscle activity. Increased passive stiffness or decreased strength in the periscapular muscles may affect their role in controlling the scapular rotation and contribute to compensation from adjacent muscles. Our findings suggest that when attempting to evaluate scapular behavior, it may be beneficial to examine muscle strength and passive stiffness of periscapular muscles.

Underwater and surface tethered swimming, lower limb strength, and somatic traits as the basic indices of young swimmers' sprint performance.

Purpose: The ability to swim fast underwater is believed to be connected to lower limb strength and some somatic traits. The main purpose of the study was to evaluate strength and speed parameters based on the relationship between the strength of underwater dolphin kicks and the countermovement jump test (CMJ) among adolescent swimmers. Methods: 48 adolescent male swimmers (13.47 ± 0.84 years) were examined for muscle mass of arms (m m arms), trunk (m m trunk), and legs (m m legs), body height (BH), and biological age (BA). An underwater tethered dolphin kicking test was conducted in a pool; average force (5F ave) and impulse per single cycle (5I ave) in the 5-second period were measured. Force indices (20F ave - average force from 20 seconds and 20I ave - average impulse per single cycle from 20 seconds) were also measured in 20-second tethered front crawl swimming. During CMJ testing, general lower body muscle motor capabilities were evaluated by extracting the work (CMJw [J]) and height (CMJh [m]) of the jump. Results: The strongest correlations were observed between: (a) 5F ave and BH, m m arms and CMJw; (b) CMJw, m m arms, and 20F ave; (c) indices of swimming speed and 5I ave (BA control); (d) total swimming velocity and average tethered swimming force (BA control). Moderate partial correlations (BA control) were noted between speed indices of swimming race and CMJ. Conclusions: The underwater tethered dolphin kick test is a useful predictor test of 50-m front crawl performance in young male swimmers, with better specificity for swimmers than CMJ results themselves.

The level of nutritional behavior and its relationship to physical condition and crawl swimming achievement among students of the Sports Sciences School at the University of Jordan

هدفت هذه الدراسة التعرف إلى العلاقة بين مستوى السلوك الغذائي مع الحالة البدنية والإنجاز الرقمي في سباحة الزحف على البطن(25م)، و(50م)، و(100م) لدى طلاب مساق سباحة (2) كلية علوم الرياضة بالجامعة الأردنية، تم استخدام المنهج الوصفي، وتكونت عينة الدراسة من (15) طالب من طلاب مساق سباحة (2) بكلية علوم الرياضة بالجامعة الأردنية، ولجمع البيانات تم استخدام استبيان السلوك الغذائي المكون من (3) مجالات وهي: (تنظيم السلوك الغذائي، وكمية الغذاء، ونوعية الغذاء) و(40) فقرة، واختبار الحالة البدنية المكون من (5) أبعاد وهي: (القوة العضلية، والتحمل، والسرعة، والمرونة، والرشاقة)، واختبار مكون من (30) عبارة، واختبار زمن سباحة (25م)، و(50م)، و(100م) زحف على البطن لقياس السرعة، وتم معالجة البيانات إحصائياً باستخدام المتوسطات الحسابية، والانحرافات المعيارية، والنسب المئوية، ومعادلة كرونباخ الفا، ومعامل الارتباط بيرسون، وأشارت نتائج الدراسة أنه كلما تحسن مستوى السلوك الغذائي زاد مستوى الحالة البدنية الكلية وأبعادها وهي: (حالة القوة العضلية، وحالة التحمل وحالة السرعة ولحالة المرونة ولحالة الرشاقة)، وأنه كلما تحسن السلوك الغذائي زاد مستوى الإنجاز الرقمي في سباحة الزحف على البطن(25م)، و(50م)، و(100م) لدى طلاب مساق سباحة (2) كلية علوم الرياضة بالجامعة الأردنية، وأوصى الباحثون بتكثيف برامج التوعية الغذائية لطلاب كلية علوم الرياضة وبيان عادات السلوك الغذائي المناسبة والحث على الالتزام بها وخاصة أثناء فترات الدراسة وعند وجود محاضرات السباحة العملية.     الكلمات المفتاحية: (كمية ونوعية الغذاء، مفهوم الذات للحالة البدنية، زمن سباحة الزحف على البطن).

MODEL PEMBELAJARAN RENANG GAYA BEBAS UNTUK PEMULA

The objective of research and development is to develop a model for crawl swimming for beginners. Additionally, extensive data on the following topics are gathered through research and development: the creation and application of beginner Basic models, in addition to assessing the child's efficiency, attractiveness, and effectiveness. This technique was created through innovative work (R and D) led by Borg and nerve. The research and development subjects are 88 elementary school students. The stages of research and development are as follows: The questionnaire and a crawl swimming test, both instruments used in research and development, are used to collect data rates from primary school-aged children: 1) specifications for the analysis; 2) evaluation by experts (the initial product evaluation); 3) restricted to a small group (testing); and the primary test, which is the fourth one. Determine the crawl level of primary school-aged children prior to administering treatments in the form of models developed to crawl swimming, as well as the crawl level of elementary school-age children following treatment or treatments that crawl swimming model to development, in order to determine the model's effectiveness. After receiving specific treatment in the form of crawl swimming models, primary school students achieved a crawl swimming proficiency of 1387, while those who took the initial tests achieved a crawl swimming proficiency of 901. As a result, crawl swimming is a good way for elementary school students to improve their crawl swimming abilities. The outcomes of the development can be used to draw the following conclusions: 1) Grade young models can be created and used in real-world training to further develop skills. 2) Information about the primary young models that have been created demonstrated their viability and improvement results creep swimming for beginners.

The Impact of Wetsuit Use on Swimming Performance, Physiology and Biomechanics: A Systematic Review

This systematic review aims to summarize the effects of wearing different types of wetsuits and swimsuits in front crawl swimming performance and physiological- and biomechanical-related variables. The Web of Science, PubMed, Scopus and the Proceedings of the International Symposium on Biomechanics and Medicine in Swimming databases were searched from inception to 25th March 2022. From the 1398 studies initially found, 26 studies were included in the review. The quality assessment and inter-rater reliability between researchers were conducted. The full body was the most studied wetsuit, with its use allowing 3.2–12.9% velocity increments in distances ranging from 25 to 1500 m, in incremental tests, in 5 and 30 min continuous swimming and in open water events. The sleeveless long vs. the full-body wetsuit led to a 400–800 m performance enhancement. Higher stroke rate, stroke length and stroke index were observed while using three different covered body part wetsuits vs. a regular swimsuit, with a lower energy cost being observed when swimming with the full-body wetsuit compared to a swimsuit. These findings provide useful information for coaches, swimmers and triathletes about the full-body and sleeveless long/short wetsuit use, since these three wetsuits allow improving swimming performance in different distances in diverse aquatic environments.

Which of the Physiological vs. Critical Speed Is a Determinant of Modern Pentathlon 200 m Front Crawl Swimming Performance: The Influence of Protocol and Ergometer vs. Swimming Pool Conditions.

Modern pentathlon includes horse riding, fencing, swimming, shooting and cross-country running. Events can last many hours during which the athletes face almost maximal energy and physiological demands, and fatigue. Early recognition and prevention of injuries and overuse syndromes can be achieved by refining the individual training loads. The purpose of the study was to determine which parameter could be the most accurate predictor of swimming working capacity determinants in pentathletes. Fourteen male pentathletes performed a continuous maximal incremental test in the swimming flume ergometer to measure peak oxygen uptake (VO2peak), and five swimming tests in a 50 m swimming pool to detect critical velocity (CV); velocity at 2 and 4 mM·L-1 of blood lactate (v2, v4) and energy cost (EC). The 200 m swimming time was 2:18-2:32 m:s (340 FINA points). CV was 1.21 ± 0.04 m·s-1, v2 was 1.14 ± 0.09 and v4 1.23 ± 0.08 m·s-1. VO2peak was 3540.1 ± 306.2 mL·min-1 or 48.8 ± 4.6 mL·kg-1·min-1. EC at 1.24 m·s-1 was 45.7 ± 2.4 mL·kg-1·min-1. Our main finding was the large correlation of CV with 200 m swimming performance; Conclusions: Among all the protocols analysed, CV is the most predictive and discriminative of individual swimming performance in this group of pentathletes. It appears as the most suitable test to constantly refine their swimming training loads for both performance enhancement and health promotion.

Kinetics and tethered strength influence the 200-m front crawl stroke kinematics and speed in young male swimmers.

Background: The aim of this research was to examine the relationship between the fast component of oxygen consumption developed in 1-min and force indices both measured in tethered swimming test and to assess the influence of the gathered indices on speed and swimming kinematics in 200-m front crawl race. Methods: Forty-eight male swimmers (aged 13.5 ± 0.9years old) participated in this study. Testing included 1) 1-min all-out front crawl tethered swimming while oxygen consumption (breath by breath) and tethered forces were measured, 2) 200-m front crawl race-like swimming featuring kinematic analysis, and 3) biological age (BA) examination. Results: During the 1-min all-out tethered swimming test, a linear increase in oxygen consumption was observed. There were moderate to high partial correlations between particular periods of seconds in the 1-min : 31-60, 41-60, and 51-60 and F max, F ave , and I ave of tethered swimming, while 41-60 and 51-60 were moderately to highly interrelated with all the swimming speed indices and SI. The swimming speed indices significantly interplayed with SL, SI, F max, F ave , and I ave . Partial correlations were computed with BA control. Conclusion: The ability of reaching a high level of fast is essential for a swimmer's energy production at short- and middle-distance events. Reaching a high level of significantly determines tethered strength and swimming kinematics. The level of influences the maintenance of a proper pulling force and the stroke technique of front crawl swimming in young male swimmers.

The Mechanical and Efficiency Constraints When Swimming Front Crawl with the Aquanex System.

The aim of this study was to compare the mechanical and efficiency constraints between free swim and swimming with differential pressure sensors (Aquanex System). These conditions were also analysed to understand the differences between sexes. Thirty young swimmers, 14 boys and 16 girls (12.31 ± 0.67 years) performed three 25-m front crawl maximal bouts under each condition: free swim and swimming with sensors. Under the condition with sensors, swimmers carried the Aquanex System composed of two hand pressure sensors (v.4.1, Model DU2, Type A, Swimming Technology Research, Richmond, VA, USA). The 25-m time (T25) was assessed as a swimming performance variable. The swimming velocity (v), stroke rate (SR), and stroke length (SL) were assessed and calculated as stroke mechanics variables. Thereafter, the stroke index (SI) and arm stroke efficiency (η F) were estimated for swimming efficiency. Statistical significance was set at p ≤ 0.05. Swimming performance was impaired when swimmers swam with sensors (overall: p = 0.03, d = 0.14; Δ = 1.30%) and a significant decrease in v was found for overall (p = 0.04, d = 0.14; Δ = 1.42%) and the girls' group (p < 0.01, d = 0.39; Δ = -1.99%). The remaining stroke mechanics variables showed no differences between conditions, as well as for swimming efficiency. Furthermore, there were no differences between girls and boys in free swim and with sensors for all variables. Swimming with the Aquanex System seems not to impose constraints in the mechanics and efficiency of young swimmers, despite differences in swimming performance and v.

ОСОБЕННОСТИ ПРИМЕНЕНИЯ ТРЕНАЖЕРА ДЛЯ ТРЕНИРОВКИ ПЛАВАТЕЛЬНОГО ГРЕБКА СПОРТСМЕНА

Statement of the problem. The theoretical analysis of the data presented in the previously carried out studies in the field of the current topic allowed us to state the need for a more detailed treatment of the topic. According to most experts, this topic is relevant from the point of view of sports achievements in competitive swimmers’ activities, i.e., the use of special technical devices (simulators) for scientifically based methodological support of a training process in the framework of sports training. The insufficiency in scientific developments and performance indicators for the use of simulators allowed us to formulate the problem, topic and purpose of the study. The purpose of the article is to consider one of the special devices (simulator) for stroke training and to identify its advantages in the training process of a swimmer. Research methodology. The research methodology is based on a set of methods adequate to it: theoretical analysis and generalization of literature, analysis of Internet resources, pedagogical observation. The experimental part of the study was carried out using a special training device (simulator). Research results. As a result of the research activity carried out, a brief description of the simulator for training swimming stroke, including blocks of nodes and instrumental methods of motion control for adjustable resistance, should be considered. In addition, the article presents an electromyographic analysis of shoulder muscles and arm muscles during training on land and under water when performing crawl swimming movements. Conclusion. The material presented in the article, obtained personally by the author, can be used in organizing sports training of swimmers as part of a training process throughout the entire annual cycle.

Kontribusi Kekuatan Otot Lengan Dan Kekuatan Otot Tungkai Terhadap Kecepatan Renang Gaya Bebas 50 Meter

Based on observations, the problem in this study is the lack of 50 meter swimming front crawl athletes in Padang. So this study aims to determine the contribution of the strength of the arm, leg muscles to the speed of 50 swimming front crawl. This research is a type of correlation with a sample of 11 athletes consisting of 6 boys and 5 girls. Sampling was done by purposive sampling. The instruments used are push ups, leg dynamometers and use a 50 meter swimming front crawl speed test in seconds. The data analysis technique used is a simple Pearson product moment multiple correlation analysis. The results showed that there was a contribution between arm muscle strength and swimming speed for male athletes by 77.9%, female athletes by 98.8%. Leg muscle strength to swimming speed for male athletes is 55.9%, female athletes are 97%. Then, the arm muscle strength and leg muscle strength together to the 50 meter swimming front crawl speed in male athletes are 72.3%, female athletes are 90.3%.

Markerless Optical Motion Capture System for Asymmetrical Swimming Stroke

This work presents the development of a markerless optical motion capture system of the front-crawl swimming stroke. The system only uses one underwater camera to record swimming motion in the sagittal plane. The participant in this experiment was a swimmer who is active in the university’s swimming club. The recorded images were then segmented to obtain silhouettes of the participant by a Gaussian Mixture Model. One of the swimming images was employed to generate a human body model that consists of 15 segments. The silhouette and model of the participant were subjected to an image matching process. The shape of the body segment was used as the feature in the image matching. The model was transformed to estimate the pose of the participant. The intraclass correlation coefficient between the results of the developed system and references were evaluated. In general, all body segments, except head and trunk, had a correlation coefficient higher than 0.95. Then, dynamics analysis by SWUM was conducted based on the joint angle acquired by the present work. The simulation implied that the developed system was suitable for daily training of athletes and coaches due to its simplicity and accuracy.

Novel Method for Estimating Propulsive Force Generated by Swimmers' Hands Using Inertial Measurement Units and Pressure Sensors.

Propulsive force is a determinant of swimming performance. Several methods have been proposed to estimate the propulsive force in human swimming; however, their practical use in coaching is limited. Herein, we propose a novel method for estimating the propulsive force generated by swimmers’ hands using an inertial measurement unit (IMU) and pressure sensors. In Experiment 1, we use a hand model to examine the effect of a hand-mounted IMU on pressure around the hand model at several flow velocities and water flow directions. In Experiment 2, we compare the propulsive force estimated using the IMU and pressure sensors () via an underwater motion-capture system and pressure sensors (). Five swimmers had markers, pressure sensors, and IMUs attached to their hands and performed front crawl swimming for 25 m twice at each of nine different swimming speeds. The results show that the hand-mounted IMU affects the resultant force; however, the effect of the hand-mounted IMU varies with the flow direction. The mean values of and are similar (19.59 ± 7.66 N and 19.36 ± 7.86 N, respectively; intraclass correlation coefficient(2,1) = 0.966), and their waveforms are similar (coefficient of multiple correlation = 0.99). These results indicate that the IMU can estimate the same level of propulsive force as an underwater motion-capture system.

Tethered force at lower limbs and swimming during a 30 s exercise bout and its association with 50 m front crawl performance

BACKGROUND: The capacity to produce force should be promoted especially for the fastest swimming events. AIM: This study aimed to analyze the effects of different test periods in mean, maximal and coefficient of force variation and to correlate the coefficient of force variation and 50m front crawl time. METHOD: Twelve well trained swimmers (age: 22.33±8.08 years, 1.69±0.48 m height, body mass 56.08±7.86 kg) randomly performed three maximal 30s repetitions of full swimming and lower limbs actions in front crawl swimming technique with ~15min resting period. A load cell system permitted the continuous measurement of exerted tethered forces, and 50m time was registered as the best time obtained at 12 months before the test. RESULTS: Mean swimming force was greater at 10s compared to 20 and 30s period (26.40 [20.66-54.20], 25.33 [21.70-52.35] and 21.39 [17.91-43.98] respectively, p&lt;0.05). Mean, maximal and force coefficient variation at tethered test with full swimming were higher than lower limbs (24.37 vs. 12.71, 77.97 vs. 39.78, 0.77 vs. 0.49 respectively, p&lt;0.05). Strong and inverse correlations were noticed between coefficient of force variation at 10 s during full swimming, at 20s during kicking and performance (28.75s [26.20-30.68s];r=-0.75;p&lt;0.01). Very strong correlation was noticed between coefficient of force variation during swimming at 20s, 30s and performance (r=-0.91 and -0.92;p&lt;0.0001). CONCLUSION: Mean swimming force at full swim and lower limbs is affected by the period of the 30s maximal tethered swimming test and is associated with performance.Data reported may be used as reference for setting training strategies at short distance events.

Biomechanical framework for the inverse dynamic analysis of swimming using hydrodynamic forces from swumsuit

This study aims to integrate an open-source software capable of estimating hydrodynamic forces solely from kinematic data with a full-body biomechanical model of the human body to enable inverse dynamic analyses of swimmers. To demonstrate the methodology, intersegmental forces and joint torques of the lower limbs were computed for a six-beat front crawl swimming motion, acquired at LABIOMEP-UP. The hydrodynamic forces obtained compare well with existing numerical literature. The intersegmental forces and joint torques obtained increase from distal to proximal joints. Overall, the results are consistent with the limited literature on swimming biomechanics, which provides confidence in the presented methodology.

Monitoring weekly progress of front crawl swimmers using IMU-based performance evaluation goal metrics.

Technical evaluation of swimming performance is an essential factor in preparing elite swimmers for their competitions. Inertial measurement units (IMUs) have attracted much attention recently because they can provide coaches with a detailed analysis of swimmers’ performance during training. A coach can obtain a quantitative and objective evaluation from IMU. The purpose of this study was to validate the use of a new phase-based performance assessment with a single IMU worn on the sacrum during training sessions. Sixteen competitive swimmers performed five one-way front crawl trials at their maximum speed wearing an IMU on the sacrum. The coach recorded the lap time for each trial, as it remains the gold standard for swimmer’s performance in competition. The measurement was carried out once a week for 10 consecutive weeks to monitor the improvement in the swimmers’ performance. Meaningful progress was defined as a time decrease of at least 0.5 s over a 25 m lap. Using validated algorithms, we estimated five goal metrics from the IMU signals representing the swimmer’s performance in the swimming phases (wall push-off, glide, stroke preparation, free-swimming) and in the entire lap. The results showed that the goal metrics for free-swimming phase and the entire lap predicted the swimmer’s progress well (e.g., accuracy, precision, sensitivity, and specificity of 0.91, 0.89, 0.94, and 0.95 for the lap goal metric, respectively). As the goal metrics for initial phases (wall push-off, glide, stroke preparation) achieved high precision and specificity (≥0.79) in progress detection, the coach can use them for swimmers with satisfactory free-swimming phase performance and make further improvements in initial phases. Changes in the values of the goal metrics have been shown to be correlated with changes in lap time when there is meaningful progress. The results of this study show that goal metrics provided by the phase-based performance evaluation with a single IMU can help monitoring swimming progress. Average velocity of the lap can replace traditional lap time measurement, while phase-based goal metrics provide more information about the swimmer’s performance in each phase. This evaluation can help the coach quantitatively monitor the swimmer’s performance and train them more efficiently.

Repeatability of ventilatory, metabolic and biomechanical responses to an intermittent incremental swimming protocol

Objective. This study aimed to determine the repeatability of ventilatory, metabolic and biomechanical variables assessed at a large spectrum of front crawl swimming intensities. We hypothesized a strong agreement (combined with a small range of variation) between a typical step protocol performed in two experimental moments. Approach. Forty competitive swimmers performed a 7 × 200 m front crawl intermittent incremental protocol (0.05 m·s−1 velocity rises and 30 s intervals) on two different occasions (48–72 h apart). Pulmonary gas exchange and ventilation were continuously measured breath-by-breath, metabolic variables were assessed during the intervals and biomechanical analysis was done at every protocol step. Main results. Concomitantly with the velocity increment, oxygen uptake, carbon dioxide production, ventilation, respiratory frequency, respiratory exchange ratio, averaged expiratory concentrations, end tidal oxygen and ventilatory equivalents for oxygen and carbon dioxide and blood lactate concentrations rose (p < 0.001), averaged expiratory concentrations and end tidal carbon dioxide and duration of inspiration, expiration and total breathing cycle decreased (p < 0.001), while tidal volume and volumes of oxygen and carbon dioxide expired maintained constant. Stroke frequency and stroke length increased and decreased (respectively) with the swimming velocity raise. No differences between experimental moments were observed in most of the assessed variables (p > 0.05), with a low dispersion (0.49%–9.94%) except for lactate concentrations and inspiration and expiration durations (11.00%–17.16%). Moderate-nearly perfect direct relationships and a good-excellent degree of reliability between moments were verified for all the assessed variables (r = 0.50–1.00, ICC = 0.76–1.00, p < 0.001), except for respiratory exchange ratio. Significance. The reliability analysis confirmed the repeatability of the assessed ventilatory, metabolic and biomechanical variables, with the obtained data well representing swimmers physiological condition when monitoring performance through a commonly used step protocol.

Contribution of biological maturation and power of upper and lower limbs to crawl swim performance in adolescent athletes

PurposeThere is no consensus in literature data about the influence of biological maturation (BM) on swim performance in young athletes. We analysed the relationship of BM, upper-limb power (ULP), and lower-limb power (LLP) with adolescent athletes’ performance in crawl swim.MethodsThis observational study determined the BM of 16 competitive swimmers (50% males and 50% females; 12.90 ± 0.88 years) by a mathematical model based on bone age and anthropometric measures. ULP and LLP were established by the horizontal launch test and the vertical and countermovement jump tests on a force platform, respectively. Swim performance was evaluated by the average speed in a 100-m crawl sprint.ResultsBM was related to ULP (males: &lt;i&gt;r&lt;/i&gt; = 0.76, &lt;i&gt;p&lt;/i&gt; = 0.001; females: &lt;i&gt;r&lt;/i&gt; = 0.39, &lt;i&gt;p&lt;/i&gt; = 0.02), LLP (males: vertical jump &lt;i&gt;r&lt;/i&gt; = 0.80, &lt;i&gt;p&lt;/i&gt; = 0.02, countermovement jump &lt;i&gt;r&lt;/i&gt; = 0.48, &lt;i&gt;p&lt;/i&gt; = 0.02; females: vertical jump &lt;i&gt;r&lt;/i&gt; = 0.30, &lt;i&gt;p&lt;/i&gt; = 0.04, countermovement jump &lt;i&gt;r&lt;/i&gt; = 0.80, &lt;i&gt;p&lt;/i&gt; = 0.01), and crawl swim performance (males: &lt;i&gt;r&lt;/i&gt; = –0.91, &lt;i&gt;p&lt;/i&gt; = 0.001; females: &lt;i&gt;r&lt;/i&gt; = –0.72, &lt;i&gt;p&lt;/i&gt; = 0.04). BM had a 87% contribution to crawl swim performance in males and a 66% contribution in females. ULP and LLP showed &lt; 50% contribution to crawl swim performance in both females and males.ConclusionsBM was associated with crawl swim performance of adolescent athletes of both sexes. BM exhibited a stronger contribution to crawl swim performance than ULP and LLP in adolescent swimmers at the puberty window.

Prevalence of exercise-induced bronchoconstriction in younger swimmers’ asthmatics and non-asthmatics in a 200 meters front crawl swimming

Background: Exercise-induced bronchospasm (EIB) present a very high prevalence among asthmatics and an increased prevalence in athletes, particularly swimmers. EIB prevalence is even higher in children. However, whether a swimming competition of 200 meters front crawl could lead to EIB in preadolescents and adolescent’s asthmatic and non-asthmatic is unknown. Objectives: Test whether a swimming competition of 200 meters front crawl could lead or detect EIB in preadolescents and adolescent’s asthmatic and non-asthmatic. Methods: Nineteen preadolescents and adolescents agreed to participate in the study, which occurred during the swimming championship of the state of Goiás. Lung function was evaluated by spirometry (FVC, FEV1, FEV1/FVC, FEF25-75%) using the Koko PFT spirometer, before and after the 200 meters front crawl. Results: The results demonstrated that for male and females, independent if there were asthmatics or not, did not present any signal of EIB or even any alteration in the lung function parameters, such as FVC, FEV1, FEV1/FVC, and FEF25-75%. Conclusions: The 200 meters front crawl, which is performed in around 2,3 minutes, did not result in exercise-induced bronchospasm in asthmatic and non-asthmatic preadolescents and adolescents.

An external focusing strategy was beneficial in experienced children but not in novices: The effect of external focus, internal focus, and holistic attention strategies

External focus (attention directed to an intended effect) has been shown to improve motor performance compared to internal focus (attention directed to body movements). Recently, holistic attention (attention directed to the overall feeling) has been discussed as an effective alternative. We hypothesized that a less specific cue (e.g. holistic attention) may be more effective than an external focus in experienced individuals. Therefore, the present study examined the effect of external focus, internal focus, and holistic attention on 14 experienced children-athletes ( Mage, 14.35 ± 1.98 years; Mheight, 171.28 ± 9.53 cm; Mweight, 58.28 ± 10.28 kg) and 14 novice children ( Mage, 14.21 ± 1.92 years; Mheight, 170.92 ± 12.40 cm; Mweight, 62.14 ± 15.62 kg). Participants completed a 16-meter front crawl swimming task with assigned instructions for three trials per condition. The results showed main effects of skill level ( p &lt; 0.001), condition ( p = 0.006), and the skill level/condition interaction ( p = 0.003). Post hoc tests revealed that external focus was superior to internal focus ( p &lt; 0.001), with no difference between holistic attention and internal focus ( p = 0.158) or holistic attention and external focus ( p = 0.05) in the experienced athletes, while none of the conditions were different in novices. The benefits of attentional focus may be influenced by the level of experience.

Intra- and inter-cycle velocity variations in sprint front crawl swimming

ABSTRACT Intra- and inter-cycle velocity variations are of utmost importance for achieving enhanced swimming performances. However, intra-cycle events can impact and interfere with the subsequent cycles, making relevant to study several consecutive cycles allowing a better understanding of this possibility. We have assessed front crawl intra- and inter-cyclic velocity variations and overall biomechanical variables in sprint front crawl swimming. Twenty-seven elite swimmers performed 25 m all-out front crawl, were videotaped using moving cameras placed at the sagittal plane and were grouped according to their sprint mean velocity. Coefficient of variation, root mean square error and mean velocity differences between two consecutive paired cycles allowed assessing intra- and inter-cycle velocity variations. Visual inspection was performed to analyse possible variability causes and independent-measures t-test allowed comparing groups. Sprint front crawl was characterised by intra- (11.12 ± 2.98) and inter-cycle velocity variation (2.27 ± 0.80 of inter-cycle velocity coefficient of variation and 0.031 ± 0.014 of root mean square error), with no differences between fastest and slowest swimmers. Front crawl intra-cycle velocity variation was not related to mean velocity and cycle sequence but considered swimmers’ personal strategy. Despite some abnormal oscillations within cycles, inter-cycle velocity variation was not caused by intra-cycle velocity variation, mean velocity or cycle sequence.