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Start time to 15 m of each participant across the season in the respective phases of the swim start.
Source publication
This study aimed to (1) track changes in body composition, lower body force-time characteristics, and swim start performance over a competitive season, and (2) investigate the intra-individual associations between changes in body composition and lower body force-time characteristics to swim start performance in five high performance swimmers (three...
Citations
... This shows that the higher a person's leg muscle strength, the better their performance in butterfly swimming starts. As in research (Thng et al., 2022), that provides some insight into the potential magnitude of change in body composition, lower body force-time characteristics, and swim start performance in high-performance swimmers within a season. By increasing leg muscle strength, it will influence better swimming start results. ...
This study aims to explore the relationship between leg muscle strength, leg power, and leg flexibility with the butterfly swimming start ability. A descriptive method with correlational study technique was used with a population consisting of Swimming Association athletes, and a sample of 12 male athletes who met the age and swimming ability criteria set. Data were collected through surveys, tests, and measurements, then analyzed using the product moment correlation technique and test-retest for validity and reliability. The results showed a significant relationship between leg muscle strength, leg power, and leg flexibility with the butterfly swimming start ability, with leg power showing the strongest relationship. Specifically, leg muscle strength had a correlation of 66.67%, leg power had a correlation of 83.33%, and leg flexibility had a correlation of 50.00% with the butterfly swimming start ability. These findings provide valuable insights for coaches and athletes in designing more effective training programs to enhance butterfly swimming start ability. Keywords: strength, power, flexibility, swimming start
... PT of muscle activation was more related to different competitive sports. In those sports requiring high explosive power, sporters needed to overcome the inertial resistance, so there exhibited shorter PT in rapid motion [42], while sporters in aquatic, swimming, road cycling fields and so on needed to overcome fluid resistance [43]. The compliance of fluid resistance was reflected in longer PT [44]. ...
In view of the importance of neck strength training and the lack of adequate training equipment, this study designed a new oscillating hydraulic trainer (OHT) of neck based on oscillating hydraulic damper. We used surface electromyography (sEMG) and subjective ratings to evaluate the neck OHT and compared the results with a simple hat trainer (HATT) and traditional weight trainer (TWT) to verify the feasibility and validity of the OHT. Under similar exercise conditions, 12 subjects performed a set of neck flexion and extension exercise with these 3 trainers. The sEMG signals of targeted muscles were collected in real time, and subjects were asked to complete subjective evaluations of product usability after exercise. The results showed that the root mean square (RMS%) of sEMG indicated that the OHT could provide two-way resistance and train the flexors and extensors simultaneously. The overall degree of muscle activation with OHT was higher than that with the other two trainers in one movement cycle. In terms of resistance characteristics exhibited by the sEMG waveform, duration (D) with OHT was significantly longer than HATT and TWT when exercising at a high speed, while Peak Timing (PT) was later. The ratings of product usability and performing usability of OHT were remarkably higher than that of HATT and TWT. Based on the above results, the OHT was proved to be more suitable for strength training, such as neck muscles, which were getting more attention gradually, but lacked mature and special training equipment.
... Concerning the low adiposity index, it can be justified by the aerobic demand of swimming training, which promotes a greater degradation of body fat. On the other hand, the biomechanical effort produced against the resistance of the water contributes to the predominance of lean body mass in swimmers of both sexes (Moraes et al., Thng et al., 2021). ...
Body morphology, due to its simple applicability, is used to help coaches make decisions during the process of identifying and selecting talent in sports. Objective: to analyze the discriminative kinanthropometric patterns of young Brazilian athletes in different sports. Materials and Methods: We evaluated 83 young males (age: 13.1 ± 2.4), 60 of whom were athletes (16-soccer, 11-tennis, 20-swimming, and 13-rowing) and 23 non-athletes (Control group). We evaluated the kinanthropometric profile by dual-energyx-ray emission absorptiometry and by anthropometry. Subsequently, through algorithms programmed in “R” language, a discriminant model was created based on the circumference variables: biceps, hips, waist, and leg; the bone diameters of the humerus and femur, and the components of body composition: total lean mass, total fat mass, bone mineral density, bone mineral content, triceps skinfold, and body adiposity index. Results: Discriminant model was able to discriminate soccer athletes in 93.8% (F:32.098; p=0.000), tennis athletes in 81.8% (F:24.060; p=0.0004), rowing athletes in 80% (F:28.031; p=0.0001), swimming at 100% (F:41.899; p<0.000) and the control group at 91.3% (F:30.132; p<0.0001). In addition, the high bone mineral density was important for the discrimination of soccer athletes (p<0.001), the low body adiposity index for the discrimination of swimming athletes (p<0.001), and the high levels of lean mass for the discrimination of rowers (p<0.001). Conclusion: We conclude that morphological patternscan be used safely, helping to discriminate young athletes from different sports; thus, one more tool to be used in the processes of detection and guidance of young people with talent in the sport.
... However, lap time can only reflect the swimmer's overall progress and not their phase-based performance. The use of biomechanical parameters such as stroke rate, stroke length, and stroke index (product of average velocity and stroke length) (Morais et al., 2013) or body composition (Thng et al., 2022) are other methods proposed by researchers to track swimmer's progress. ...
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.
Introduction
The purpose of this study was to investigate the effect of environmental conditions on body composition, upper body power, and lower body power throughout a ∼4-week military mountain training exercise. We hypothesized that countermovement jump and ballistic push-up performance would decrease as a result of extended mountain field training and that winter (cold) conditions would result in greater decrements compared to fall (temperate) conditions. We also expected to observe a strong positive correlation between changes in performance and changes in skeletal muscle mass. Finally, we expected acute changes in performance upon altitude exposure.
Materials and Methods
A total of 111 U.S. Infantry Marines (110 M; 1 F) provided written informed consent to participate in this study according to a protocol approved by the Naval Health Research Center. There were 54 participants in the fall cohort and 57 in the winter cohort. Maximum effort countermovement jump and ballistic push-up performance were assessed at different timepoints: (1) baseline at the sea level, (2) before training at ∼2100 m, (3) midpoint of training at ∼2100 m, (4) end of training at ∼2100 m, and (5) after 3 to 4 weeks of recovery at the sea level. The fall cohort trained at moderate temperatures (average day/night, 20°C/3°C), whereas the winter cohort trained under snowy winter conditions (7°C/−14°C).
Results
The results suggested that seasonal conditions did not significantly affect changes in body composition or physical performance. Furthermore, no acute effects of altitude on physical performance were detected. Training exercise did, however, cause performance decrements in countermovement jump height, countermovement jump peak power, and ballistic push-up height. Repeated measure correlation analyses suggested that there was a weak positive correlation between the decrease in skeletal muscle mass and the decrease in countermovement jump peak power throughout the training.
Conclusions
The results of our study suggest that explosive movements are negatively affected by extended military training, seemingly independent of environmental training conditions or temperature. Planning and execution of military training should account for the likelihood that warfighter physical power will decline and may not return to pretraining levels within the month following the training event. It may also be advised to consider targeted exercises to aid in recovery of muscular strength and power. Future work should consider additional factors that likely influenced the decrease in physical performance that occurs during extended military training, such as nutrition, sleep, and psychological and cognitive stresses.
The aims of this study were to: (1) analyze and compare the stroke kinematics between junior and senior elite male swimmers in every section of the race during the 50-m freestyle event, and; (2) identify stroke frequency (SF)–stroke length (SL) combinations on swim speed independently for junior and senior swimmers in each section of the 50-m freestyle event. Eighty-six junior swimmers (2019) and 95 seniors (2021) competing in the 50-m long course meter LEN Championships were analyzed. The t-test independent samples (p ≤ 0.05) were used to compare juniors and seniors. The SF and SL combinations on swim speed were explored using three-way ANOVAs. Senior swimmers were significantly faster in the 50-m race than juniors (p < 0.001). Speed presented the largest significant difference (p < 0.001) in section S0-15 m (start until the 15th meter mark) being seniors fastest. Both junior and senior swimmers revealed a significant categorization (p < 0.001) by stroke length and stroke frequency in each race section. It was possible to model several SF–SL combinations for seniors and juniors in each section. The fastest swim speed in each section, for seniors and juniors independently, was achieved by a SF–SL combination that may not be the fastest SF or the longest SL. Coaches and swimmers must be aware that despite the 50-m event being an all-out bout, several SF–SL combinations were observed (independently for juniors and seniors), and they differ between race sections.
Stadnyk, M, Sepehri, M, Cook, M, Adeeb, S, and Westover, L. Quantifying asymmetry and performance of lower limb mechanical muscle function in varsity athletes-using non-countermovement jumps. J Strength Cond Res 37(1): 98-106, 2023-The ability to automatically quantify jump performance and lower limb muscle function in athletes would be beneficial for both training and rehabilitation purposes. Countermovement jumps (CMJs) and non-CMJs (NCMJs) are simple, quick, and require relatively inexpensive equipment to effectively and reliably monitor lower limb function. In a previous study, CMJ characteristics were assessed across different varsity sports. This study is a follow-up study to incorporate NCMJs into assessing jump characteristics of the same sports and investigate the additional information provided by the complementary jump type. The main objective of this study was to look at a means of quantifying the lower limb mechanical muscle function automatically to provide information for rehabilitation and performance purposes in athletes of specific sports. Male and female varsity athletes from 4 different sports completed 5 trials of an NCMJ on dual force plates. An analysis program was developed using Wolfram Mathematica to analyze force-time jump data. Various parameters of interest were generated, including peak force, force-time curve shape classification, jump phase lengths, phase-specific kinetic impulse, asymmetry index, takeoff velocity, jump height, phase-specific center of mass displacements, and reactive strength index modified. Results obtained indicate that similar jump characteristics to the CMJ study can be quantified, which can be used for performance enhancement or injury rehabilitation. Additional data found, such as the ability of an athlete to hold a steady squat during an NCMJ, could also be meaningful in aiding trainers to design programs tailored for athletes.
