Browsing by Author "Lopes, Tiago J."
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- Analysis of upper limb propulsion in young swimmers in front-crawl through Statistical Parametric MappingPublication . Morais, J.E.; Barbosa, Tiago M.; Lopes, Tiago J.; Gourgoulis, Vassilios; Nikodelis, Thomas; Marinho, D.A.This study aimed to: (i) verify the within-subject effect of the dominant and non-dominant upper limb propulsion during consecutive arm-pulls through discrete (average) and continuous analysis (SPM), and; (ii) compare young swimmers’ propulsion between both upper limbs through discrete (average) and continuous analysis (Statistical Parametric Mapping – SPM). The sample consisted of 17 young male swimmers (age = 16.02 ± 0.61-years) who regularly participate in national and international level competitions. A set of kinematic and propulsion variables were measured during a 25-m maximal trial in front-crawl. Statistical analysis of propulsion was performed using discrete variables and through SPM. Swimming velocity showed a significant decrease over time. A significant interaction between the “time” (consecutive arm-pulls) and “side” (dominant vs. non-dominant) effects was observed in both statistical analyzes. Only the dominant upper limb demonstrated a significant “time” effect with a significant difference (p < 0.05) between the first and third arm-pulls. SPM indicated that the “time” effect was observed between the ~ 34% and ~ 42% of the arm-pull. The differences between the first and third arm-pull were verified between the ~ 32% and ~ 43% of the arm-pull. A non-significant “side” effect was verified in both analyzes. Therefore, SPM analysis provided more sensitive and accurate outputs than discrete analysis. This will allow coaches to design specific training drills focused on specific moments of the arm-pull
- Comparison of swimming velocity between age-group swimmers through discrete variables and continuous variables by Statistical Parametric MappingPublication . Morais, J.E.; Barbosa, Tiago M.; Lopes, Tiago J.; Moriyama, Shin-Ichiro; Marinho, D.A.The aim of this study was to compare the swimming velocity in frontcrawl between age-group swimmers using discrete variables against Statistical Parametric Mapping (SPM). The sample consisted of 30 young male swimmers divided into three groups (each with 10 swimmers) based on their age (group #1: 13.60 ± 0.84 years; group #2: 15.40 ± 0.32 years; group 3: 16.39 ± 0.69 years). Swimmers performed three maximal trials in front-crawl. The best performance was used for analysis. Comparison of swimming velocity between groups was analysed using discrete variables and as a continuous variable (SPM). As a discrete variable, the mean swimming velocity showed a significant difference between groups (p < 0.05). Moreover, when analysed by SPM, swimming velocity showed a significant difference (p = 0.021) between the ~ 44% and ~ 51% of the stroke cycle (transition of the propulsion phases between sides). Post-hoc comparison revealed a significant difference between group #1 and group #3 only in SPM analysis. Researchers, coaches, and practitioners should know that both measurement approaches can be used simultaneously. However, SPM offers more sensitive and accurate results about the swimmers’ stroke cycle.
- Comparison of the Active Drag and Passive Drag Coefficients at the same Swimming Speed Through Experimental MethodsPublication . Lopes, Tiago J.; Pinto, Mafalda P.; Oliveira, João P.; Marinho, Daniel A.; Morais, J. E.; Sampaio, TatianaStudies about drag in swimming usually report or put the focus on its absolute value. However, it is being claimed that the drag coefficient better represents the hydrodynamic profile of a swimmer. Drag is strongly dependent on speed. Thus, increases in speed will lead to increases in drag. This could lead to misleading interpretations since drag is the water resistance that makes the swimmers’ displacement difficult. Conversely, the drag coefficient is less dependent on speed, which can be seen as a more appropriate measure of the swimmers’ hydrodynamic profile. This study used a complete experimental methodology (experimental and cross-sectional study) to determine the resistive forces in crawl swimming at the same speed (i.e., 1.00, 1.05, 1.10 m/s, etc.). In 10 proficient non-competitive adult swimmers (seven men and three women), the drag coefficient (CD ) was compared and the difference between using the technical drag index (TDI) with drag (D, passive or active) or with its respective CD 's. Measurements of active drag (DA ), passive drag (DP ) and CD (CDA and CDP ) were carried out. The TDI was calculated as a measure of swimming efficiency and the frontal surface area (FSA) obtained in active conditions. The active FSA was 20.73 ± 5.56% greater than the passive FSA (large effect size), the propulsion was 58.29 ± 69.61% greater than drag and CDA was 24.60 ± 46.55% greater than CDP (moderate effect size). TDI was significantly lower, but with a small effect size when measured with CD values compared to drag. TDID vs TDICD revealed strong agreement (> 80% of plots were within IC95). This study concludes that proficient swimmers presented a CDA greater than the CDP, but with strong agreement between them, probably due to FSA during active conditions. CD data appears to be a more absolute indicator of drag than TDI.
- Numerical and experimental methods used to evaluate active drag in swimming: a systematic narrative reviewPublication . Lopes, Tiago J.; Morais, J.E.; Pinto, Mafalda P.; Marinho, D.A.In swimming, it is necessary to understand and identify the main factors that are important to reduce active drag and, consequently, improve the performance of swimmers. However, there is no up-to-date review in the literature clarifying this topic. Thus, a systematic narrative review was performed to update the body of knowledge on active drag in swimming through numerical and experimental methods.
- Race analysis of the men’s 50 m events at the 2021 LEN European ChampionshipsPublication . Morais, J.E.; Barbosa, Tiago M.; Lopes, Tiago J.; Simbaña-Escobar, David; Marinho, D.A.The aim of this study was to: (i) characterise the stroke kinematics’ stability of the male swimmers competing in the four 50 m events at the 2021 European Championships, and; (ii) understand the speed–time relationship in the four race events. All male swimmers who participated in the 50 m events (backstroke: 78 swimmers; breaststroke: 79 swimmers; butterfly: 89 swimmers; freestyle: 95 swimmers) were evaluated. In each swimming stroke swimmers were split in two groups (better and poorer performances). Significant variances (p < 0.05) were observed in both groups in all variables and for all swimming strokes. Swimming speed was the variable with the highest variance in both groups and strokes. Overall, better swimmers presented a low to high normative stability, and poorer swimmers a moderate-to-high. Speed–time curve fitting for all swimming strokes and groups suggested a cubic relationship. It can be considered that elite male swimmers racing 50 m sprint events at major competitions present an all-out trend. The present data provide coaches with substantial information about the main trend in the 50 m sprint events, specifically in each section of the race.
- Race level comparison and variability analysis of 100 m freestyle sprinters competing in the 2019 European championshipsPublication . Morais, J.E.; Barbosa, Tiago M.; Lopes, Tiago J.; Marinho, D.A.This study aimed to (i) compare the race performance of the swimmers with better performances and poorer performances during all sections of a 100 m freestyle event and (ii) compare stroke kinematics variables between tiers and analyse their stability in each tier. The sample was composed of 88 swimmers that participated in the 100 m Freestyle event at the 2019 LEN European Junior Championships. Speed achieved the largest difference between tiers in section (S) S0-15 m of lap #1 (mean difference = -0.109 s, p < 0.001). During the clean swim and finish phases, the stroke length and stroke index presented significant differences (p < 0.05) between tiers in all sections of the race (stroke frequency did not). Significant variances were noted for both tiers in all variables in both laps. Swimmers in tier #1 were significantly faster than swimmers in tier #2 especially in sections related to the push-off against a solid (block or wall), and finish. A significant variance was noted by both tiers during the race with a moderate-to-high normative stability. Coaches are advised to analyse and understand the swimmers' within-lap stability, which can give deeper details about their swimmers' behaviour during the 100 m freestyle race.
- Smartpaddle® as a new tool for monitoring swimmers’ kinematic and kinetic variables in real timePublication . Marinho, D.A.; Barbosa, Tiago M.; Auvinen, Ari; Lopes, Tiago J.; Silva, A.J.; Morais, J.E.Smart technology, such as wearables, applied to sports analysis is essential for performance enhancement. New technological equipment can promote the interaction between researchers, coaches, and athletes, facilitating information exchange in real time. Objective: The aim of this study was to present new wearable equipment (SmartPaddle®) to measure kinematic and kinetic variables in swimming and understand the agreement of the propulsive force variable with a pressure sensor system. Methods: Four male university swimmers (18.75±0.50 years old, 71.55±6.80 kg of body mass, and 175.00±5.94 cm of height) were analyzed. The SmartPaddle® and a pressure sensor system were used to collect the kinetic data (propulsive force). The comparison between the propulsive force methods was based on t-test paired samples, simple linear regression, and Bland-Altman plots. Results: SmartPaddle® is a system that consists of (i) a wearable device, (ii) the Trainesense Session Manager mobile application for recording, and; (iii) the Analysis Center for analysis and data storage. It records a set of kinematic and kinetic parameters useful for coaches daily. The comparison between the different methods revealed non-significant differences and a very-high relationship. Conclusion: SmartPaddle® is a feasible wearable device that swimmersswimmers can use can use to provide immediate data about their kinematic and kinetic profile. Coaches can easily monitor these parameters and give immediate suggestions to their swimmers on a daily basis.
- Using statistical parametric mapping to compare the propulsion of age-group swimmers in front crawl acquired with the Aquanex systemPublication . Morais, J.E.; Marinho, D.A.; Oliveira, João P.; Sampaio, Tatiana; Lopes, Tiago J.; Barbosa, Tiago M.Understanding the difference in each upper limb between age groups can provide deeper insights into swimmers’ propulsion. This study aimed to: (1) compare swimming velocity and a set of kinematical variables between junior and juvenile swimmers and (2) compare the propulsion outputs through discrete and continuous analyses (Statistical Parametric Mapping—SPM) between junior and juvenile swimmers for each upper limb (i.e., dominant and non-dominant). The sample was composed of 22 male swimmers (12 juniors with 16.35 0.74 years; 10 juveniles with 15.40 0.32 years). A set of kinematic and propulsion variables was measured at maximum swimming velocity. Statistical Parametric Mapping was used as a continuous analysis approach to identify differences in the propulsion of both upper limbs between junior and juvenile swimmers. Junior swimmers were significantly faster than juveniles (p = 0.04, d = 0.86). Although juniors showed higher propulsion values, the SPM did not reveal significant differences (p < 0.05) for dominant and non-dominant upper limbs between the two age groups. This indicates that other factors (such as drag) may be responsible for the difference in swimming velocity. Coaches and swimmers should be aware that an increase in propulsion alone may not immediately lead to an increase in swimming velocity.
- Using wearables to monitor swimmers’ propulsive force to get real-time feedback and understand its relationship to swimming velocityPublication . Lopes, Tiago J.; Sampaio, Tatiana; Oliveira, João P.; Pinto, Mafalda P.; Marinho, D.A.; Morais, J.E.Evidence on the role of propulsion compared to drag in swimming, based on experimental settings, is still lacking. However, higher levels of propulsion seem to lead to faster swimming veloci- ties. The aim of this study was to understand the variation in a set of kinematic and kinetic variables between two swimming sections and their relationship to swimming velocity. The sample consisted of 15 young adult recreational swimmers (8 males: 20.84 ± 2.03 years; 7 females: 20.13 ± 1.90 years). Maximum swimming velocity and a set of kinematic and kinetic variables were measured during two consecutive sections of the swimming pool. Differences between sections were measured and the determinants of swimming velocity were analyzed. Swimming velocity, propulsive force, and the other kinematic and kinetic variables did not change significantly (p < 0.05) between sections (only the intra-cyclic fluctuation of swimming velocity decreased significantly, p = 0.005). The modeling identified the propulsive force, stroke length, and active drag coefficient as the determinants of swimming velocity. Swimming velocity was determined by the interaction of kinematic and kinetic variables, specifically propulsive force and active drag coefficient