241 research outputs found
Comparison of the World and European Records in the 100m Dash by a Quasi-Physical Model
The aim was to employ a quasi-physical model to analyse the performance and biomechanics of the World and European records at the 100m
dash in Athletics. At the time of this research, the World record was hold by Usain Bolt (Jamaica) with 9.58s and the European record 9.86s by
Francis Obikwelu (Portugal). The analysis of the performance employs a quasi-physical model that feature the drive, maintenance, velocity and
drag terms. Obikwelu showed a slower start (drive term) and Bolt a lower rate of deceleration over the race (propulsive term). The velocity and
drag terms were higher for Bolt. Correcting the race time for a hypothetical null wind speed, BoltÂŽs time would have been 9.62s (i.e. a 0.04s
impairment) and 9.89s for Obikwelu (i.e. a 0.03s impairment).info:eu-repo/semantics/publishedVersio
The determination of drag in the gliding phase in swimming
The hydrodynamic drag forces produced by the swimmer during the sub aquatic gliding have been analyzed appealing to experimental investigation methods (e.g., Lyttle et al., 2000). However, the obtained results varied, which can translate some of the main inherent difficulties involved in the experimental studies. Thus, through application of a numerical method of Computational Fluid Dynamics (CFD), we intended to study the hydrodynamic drag forces, created during the displacement of the swimmer in different gliding positions, attempting to address some practical concerns to swimmers and coaches
Physiological assessment of head-out aquatic exercises in healthy subjects: a qualitative review
In the last decades head-out aquatic exercises became one of the
most important physical activities within the health system.
Massive research has been produced throughout these decades
in order to better understand the role of head-out aquatic exercises
in populationsâ health. Such studies aimed to obtain comprehensive
knowledge about the acute and chronic response of
subjects performing head-out aquatic exercises. For that, it is
assumed that chronic adaptations represent the accumulation of
acute responses during each aquatic session. The purpose of this
study was to describe the âstate of the artâ about physiological
assessment of head-out aquatic exercises based on acute and
chronic adaptations in healthy subjects based on a qualitative
review. The main findings about acute response of head-out
aquatic exercise according to water temperature, water depth,
type of exercise, additional equipment used, body segments
exercising and music cadence will be described. In what concerns
chronic adaptations, the main results related to cardiovascular
and metabolic adaptations, muscular strength, flexibility
and body composition improvements will be reported
Training evaluation in male age-group swimmers
Monitoring the training process represents an important task during sports preparation. However, not always the applied protocols help to address the coachesâ concerns, namely regarding its complexity and difficulty to be used in large samples. Therefore, the aim of this study was to apply a simple protocol to control the training process in a group of male age-group swimmer
âYoungâ masters vs. elite swimmers: comparison of performance, energetics, kinematics and efficiency
Competition in masters swimming is getting tougher. Athletes are dedicating more time and effort to excel in masters competitions than they use to. Research question: What are the factors associated with masters and elite swimmers performance? Type of study: A cohort group comparison (young master versus elite swimmers) and a correlational study (association between selected variables and performance) were conducted. Purpose: The aim was to identify the energetics, kinematics and efficiency variables associated with young masters (former elite) and elite swimmers performance as well as compare it between both cohort groups. Methods: Twenty male swimmers (masters: N=8, 29.75±3.80-y; elite: N=12, 20.41±3.20-yld) performed a 7x200m freestyle swim. The performance (200m freestyle at official competition), velocity at which the 4 mmol.l-1 of blood lactate was assessed (V4), peak blood lactate concentrations (Lapeak), peak oxygen up-take (VO2peak), minimum velocity to elicited VO2peak (vVO2peak), total energy expenditure (Ätot), stroke frequency (SF), stroke length (SL), mean swimming velocity (v), energy cost (C), stroke index (SI) and propelling efficiency (p) to check whether this was achieved. Results: Elite swimmers presented a better performance. V4, VO2peak, vVO2peak, Ätot , SF, v and SI were significantly higher in elite swimmers. For both groups performance was associated with the V4, vVO2peak and v. In addition, elite swimmersâ performance was impaired with regard to the Lapeak. Conclusions: Young masters swimmers presented impairment in performance related to a decrease in the energetics profile and biomechanical behaviour. Nevertheless, their previous background as elite swimmers allowed them to maintain high swimming efficiency
Effects of musical cadence in the acute physiologic adaptations to head-out aquatic exercises
The purpose of this study was to
analyze the relationships between musical cadence and the
physiologic adaptations to basic head-out aquatic exercises.
Fifteen young and clinically healthy women performed, immersed
to the breast, a cardiovascular aquatic exercise called
the âârocking horse.ââ The study design included an intermittent
and progressive protocol starting at a 90 b min21 rhythm and
increasing every 6 minutes, by 15 b min21, up to 195 b min21 or
exhaustion. The rating of perceived effort (RPE) at the maximal
heart rate achieved during each bout (HRmax), the percentage
of the maximal theoretical heart rate estimated (%HRmax), and
the blood lactate concentration ([La-]) were evaluated. The
musical cadence was also calculated at 4 mmol L21 of blood
lactate (R4), the RPE at R4 (RPE@R4), the HR at R4 (HR@R4),
and the %HRmax at R4 (%HRmax@R4). Strong relationships
were verified between the musical cadence and the RPE
(R2 = 0.85; p , 0.01), the HRmax (R2 = 0.66; p , 0.01), the
%HRmax (R2 = 0.61; p , 0.01), and the [La-] (R2 = 0.54;
p , 0.01). The R4 was 148.13 6 17.53 b min21, the RPE@R4
was 14.53 6 2.53, the HR@R4 was 169.33 6 12.06 b min21,
and the %HRmax@R4 was 85.53 6 5.72%. The main conclusion
is that increasing musical cadence created an increase
in the physiologic response. Therefore, instructors must choose
musical cadences according to the goals of the session they
are conducting to achieve the desired intensity
Longitudinal assessment of swimming performance in the 200 m freestyle event
Several studies have been carried
out in order to identify the factors
that can predict swimming performance.
However, all these studies only
analyzed determinant factors in a
single moment. It was not taken into
account the longitudinal stability and
changes, as a result of individual development,
new training methods
and technological sophistication
Longitudinal assessment of elite swimmers performance leading to 2008 Beijing Olympic Games
The aim of this research was to track and analyze the stability of 400-m freestyle performance throughout elite swimmers preparation to the 2008 Beijing Olympic Game
Tracking the 2004-2008 Olympic cycle performance in long distance freestyle events
Swimming seems to be one of the
most studied sport among Sport Sciences
community. Researchers are
constantly attempting to identify and
understand the factors that can predict
swimming performance with a
higher accuracy (e.g., Silva et al.,
2007)
100m and 200m front crawl performance prediction based on anthropometric and physiological measurements
Background: The identification of the variables that are able to predict swimming performance is one of the main purposes of the âswimming scienceâ community. Research question: The aims of the study were: (i) to compare the anthropometric and physiological profiles of 100m and 200m front crawl swimmers and; (ii) to identify anthropometric and physiological variables that account for the prediction of the swimming performance at the 100m and 200m front crawl events. Methods: Twenty-six male swimmers were divided in two groups (12 for 100m group and 14 to 200m group). The swimmersâ personal best performance for the 100m and the 200m front crawl was converted to FINA points. The subjects performed a graded swimming test and an all-out test (100 or 200m maximal swims) in different days, in which physiological measures were evaluated. Forward step-by-step linear regression models were computed to predict swimming performance. The subjectsâ performances (season best and all-out test) were taken as dependent variables. The age, physiological and anthropometric measures were selected as independent variables. Results: Anthropometric and physiological profiles of 100 and 200m swimmers are different and the mean oxygen uptake during exercise combined with training experience may explain 200m front crawl best season performance with a high precision (â2% error). The models computed were able to predict from 44 % (i.e. 200m all-out bout) to 61 % (i.e. 200m season best) swimming performance. Predictive power of the models was less accurate in the 100m event (error > 10%). Conclusions: The authors conclude that the extent to which the physiological and anthropometric variables combine to predict performance probable is group-specific
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