Effects of anthropometrics, thrust, and drag on stroke kinematics and 100 m performance of young swimmers using path-analysis modeling.

The aim of this study was to understand the interactions between anthropometric, kinetic, and kinematic variables and how they determine the 100 m freestyle performance in young swimmers. Twenty-five adolescent swimmers (15 male and 10 female, aged 15.75 ± 1.01 years) who regularly participated in regional and national competitions were recruited. The 100 m freestyle performance was chosen as the variable to be predicted. A series of anthropometric (hand surface area-HSA), kinetic (thrust and active drag coefficient (CDA )), and kinematic (stroke length (SL); stroke frequency (SF), and swimming speed) variables were measured. Structural equation modeling (via path analysis) was used to develop and test the model. The initial model predicted performance with 90.1% accuracy. All paths were significant (p < 0.05) except the thrust-SL. After deleting this non-significant path (thrust-SL) and recalculating, the model goodness-of-fit improved and all paths were significant (p < 0.05). The predicted performance was 90.2%. Anthropometrics had significant effects on kinetics, which had significant effects on kinematics, and consequently on the 100 m freestyle performance. The cascade of interactions based on this path-flow model allowed for a meaningful prediction of the 100 m freestyle performance. Based on these results, coaches and swimmers should be aware that the swimming predictors can first meaningfully interact with each other to ultimately predict the 100 m freestyle performance.

A Single Dose of Beetroot Juice not Enhance Performance during Intervallic Swimming Efforts.

Despite the numerous scientific evidence on the topic, there is no clear and consistent answer that clarifies the true effects of beetroot juice (BJ) supplementation on different types of physical performance. This study examined whether an acute intake of BJ improves swimming performance, physiological variables of anaerobic metabolism, or subjective measures during high-intensity interval exercise with incomplete rest in competitive swimmers. Eighteen competitive swimmers (nine females and nine males) participated in this cross-over randomized, placebo-controlled, double-blind and counterbalanced study. In two trials, swimmers ingested BJ (70 mL, 6.4 mmol/400 mg NO3-) or placebo (PLA) (70 mL, 0.04 mmol/3 mg NO3-) three hours before a 2×6×100 m maximal effort with 40 seconds rest between repetitions and three minutes between blocks. The 100 m times showed no differences between groups (p > 0.05), but there was an interaction between block×repetition×condition (F5 = 3.10; p = 0.046; ηp2 = 0.54), indicating that the BJ group decreased the time of the sixth repetition of block2 compared to block1 (p = 0.01). Lactate concentration showed no differences between conditions (p > 0.05), but there was a main effect of block (ηp2 = 0.60) and a block×repetition interaction (ηp2 = 0.70), indicating higher values in block2 and increasing values between repetitions in block1. The subjective scales, perception of exertion (RPE) and Total Quality Recovery (TQR), showed no effects of condition (p > 0.05), but BJ swimmers had a greater TQR in the last repetitions of each block. In conclusion, a single dose of BJ did not enhance intermittent swimming performance or modified the physiological (lactate and heart rate) or subjective (RPE and TQR) variables; although there was a possible positive effect on the exercise tolerance at the end of effort.

Identifying Differences in Swimming Speed Fluctuation in Age-Group Swimmers by Statistical Parametric Mapping: A Biomechanical Assessment for Performance Development.

The aim of this study was to compare the assessment of swimming speed processed as a discrete variable and as a continuous variable in young swimmers. One-hundred and twenty young swimmers (60 boys: age = 12.91 ± 0.86 years; 60 girls: age = 12.46 ± 0.94 years) were analysed. The dataset for each sex was divided into three tiers: (i) tier #1 - best-performing swimmers; (ii) tier #2: intermediate-performing swimmers, and; (iii) tier #3 - poorest-performing swimmers. As a discrete variable, swimming speed showed significant sex and tier effects, and a significant sex*tier interaction (p < 0.001). Speed fluctuation showed a non-significant sex effect (p > 0.05), a significant tier effect (p < 0.001), and a non-significant sex*tier interaction (p > 0.05). As a continuous variable, the swimming speed time-curve presented significant sex and tier effects (p < 0.001) throughout the stroke cycle, and a significant sex*tier interaction (p < 0.05) in some moments of the stroke cycle. Swimming speed fluctuation analysed as a discrete variable and as a continuous variable can be used in a complementary way. Nonetheless, SPM can provide deeper insight into differences within the stroke cycle. Thus, coaches and practitioners should be aware that different knowledge about the swimmers' stroke cycle can be learned by assessing swimming speed using both methods.

Race Analysis and Determination of Stroke Frequency - Stroke Length Combinations during the 50-M Freestyle Event.

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.

Profiling of elite male junior 50 m freestyle sprinters: Understanding the speed-time relationship.

The aim of this study was to (1) analyze and compare the race performance and stability between the fastest and slowest male swimmers during the 50 m freestyle event, and (2) to understand the speed-time relationship in this race. The performances (start, clean swim, and finish) of 86 swimmers (divided into two tiers: best and poorest performances) who competed in the 50 m freestyle event in the 2019 long course LEN European Junior Championships were analyzed. The swimming speed presented a significant difference between the groups (tier #1 vs tier #2) in all sections of the race, in which the start (S0-15 m: p < 0.001, d = 1.64) and finish sections (S45-50: p < 0.001, d = 1.63) showed the greatest differences. Significant variances over the race sections were noted for both groups in all variables, in which the swimming speed was the variable with the highest variance (tier #1: p < 0.001, η2  = 0.72; tier #2: p < 0.001, η2  = 0.82). Both groups exhibited a similar normative stability, with the fastest swimmers tending to be the best in all sections. The fit analysis produced a cubic speed-time relationship. Notwithstanding, junior swimmers who raced the 50 m freestyle can be considered to have an all-out pacing. This information is of paramount importance for coaches and swimmers to understand the intra-lap race performance in this short event.

Wearables in Swimming for Real-Time Feedback: A Systematic Review.

Nowadays, wearables are a must-have tool for athletes and coaches. Wearables can provide real-time feedback to athletes on their athletic performance and other training details as training load, for example. The aim of this study was to systematically review studies that assessed the accuracy of wearables providing real-time feedback in swimming. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were selected to identify relevant studies. After screening, 283 articles were analyzed and 18 related to the assessment of the accuracy of wearables providing real-time feedback in swimming were retained for qualitative synthesis. The quality index was 12.44 ± 2.71 in a range from 0 (lowest quality) to 16 (highest quality). Most articles assessed in-house built (n = 15; 83.3%) wearables in front-crawl stroke (n = 8; 44.4%), eleven articles (61.1%) analyzed the accuracy of measuring swimming kinematics, eight (44.4%) were placed on the lower back, and seven were placed on the head (38.9%). A limited number of studies analyzed wearables that are commercially available (n = 3, 16.7%). Eleven articles (61.1%) reported on the accuracy, measurement error, or consistency. From those eleven, nine (81.8%) noted that wearables are accurate.

Using Statistical Parametric Mapping to Compare the Propulsion of Age-Group Swimmers in Front Crawl Acquired with the Aquanex System.

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 Mapping­SPM) 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.

The Effects of 32 Weeks of Multicomponent Training with Different Exercises Order in Elderly Women's Functional Fitness and Body Composition.

Background and objectives: Starting the multicomponent training sessions with aerobic-based exercises or resistance-based exercises may have different effects on functional fitness and body composition. Thus, the aim of this study was to assess the effects of the order of exercises in elderly women's physical fitness and body composition by multicomponent training. Materials and Methods: A sample of 91 elderly females, aged between 60 and 81, were randomly divided into three groups (A, B, C). Each group performed the following order of exercises: Group A consisted of warm-up followed by aerobic training, strength training, stretching and cool down; Group B consisted of warm-up followed by strength training, aerobic training, stretching and cool down; while the control group (C) did not perform any exercise. Functional fitness and body composition were assessed at 3 moments of the 32 weeks (baseline and after each 16-week) intervention. One-way ANOVA for comparison between groups, ANOVA for repeated measures and multiple linear regression were used for statistical analysis. Results: The results showed that the functional fitness and body composition varied over the 32 weeks of multicomponent training. However, group A seems to show higher improvements in more variables. Conclusion: In the current study, group A obtained better results in most of the evaluated parameters. Thus, to improve functional fitness, warm-up, followed by aerobic training, strength training and relaxation may be the most suitable training for elderly women.

Effect of Blood Flow Restriction Technique on Delayed Onset Muscle Soreness: A Systematic Review.

Background and Objectives: The effect of the blood flow restriction technique (BFR) on delayed onset muscular soreness (DOMS) symptoms remains unclear. Since there is no consensus in the literature, the aim of the present study is to systematically identify and appraise the available evidence on the effects of the BFR technique on DOMS, in healthy subjects. Materials and Methods: Computerized literature search in the databases Pubmed, Google Scholar, EBSCO, Cochrane and PEDro to identify randomized controlled trials that assessed the effects of blood flow restriction on delayed onset muscular soreness symptoms. Results: Eight trials met the eligibility criteria and were included in this review, presenting the results of 118 participants, with a mean methodological rating of 6/10 on the PEDro scale. Conclusions: So far, there is not enough evidence to confirm or refute the influence of BFR on DOMS, and more studies with a good methodological basis are needed, in larger samples, to establish protocols and parameters of exercise and intervention. Data analysis suggests a tendency toward the proinflammatory effect of BFR during high restrictive pressures combined with eccentric exercises, while postconditioning BFR seems to have a protective effect on DOMS. Prospero ID record: 345457, title registration: "Effect of Blood Flow Restriction Technique on the Prevention of Delayed Onset Muscle Soreness: A Systematic Review".

Comparing the effects of plyometric and isometric strength training on dynamic and isometric force-time characteristics.

The purpose of the study was to compare the change in dynamic and isometric force-time characteristics after plyometric (PLYO) or isometric strength training (ISO). Twenty-two endurance runners (age = 37 ± 6 years, stature = 1.71 ± 0.05 m, body mass = 62.7 ± 8.6 kg, weekly mileage = 47.3 ± 10.8 km) performed a countermovement jump (CMJ) and isometric mid-thigh pull (IMTP) test during pre- and post-tests. They were then randomly assigned to either PLYO or ISO group and completed 12 sessions of intervention over six weeks. The PLYO included drop jump, single leg bounding and split jump, and the ISO included IMTP and isometric ankle plantar flexion. Significant and large time x group interactions were observed for CMJ countermovement depth (P = 0.037, ƞ²p = 0.21) and IMTP and relative peak force (PF) (P = 0.030, ƞ² p = 0.22). Significant and large main effects for time were observed in CMJ height, peak power, propulsive phase duration, countermovement depth, reactive strength index modified, IMTP PF and relative PF (P < 0.05, 0.20 ≤ ƞ²p ≤ 0.65). Effect for time showed small improvement in CMJ height for both PLYO (P < 0.001, d = 0.48) and ISO (P = 0.009, d = 0.47), small improvement in CMJ PP in PLYO (P = 0.020, d = 0.21), large increase in countermovement depth (P = 0.004, d = 1.02) and IMTP relative PF (P < 0.001, d = 0.87), and moderate increase in propulsive phase duration (P = 0.038, d = 0.65) and IMTP PF (P < 0.001, d = 0.55) in ISO. There were large differences between groups for percentage change in countermovement depth (P = 0.003, d = 0.96) and IMTP relative PF (P = 0.047, d = 0.90). In conclusion, both PLYO and ISO improved CMJ jump height via different mechanisms, while only ISO resulted in improved IMTP PF and relative PF.

Propulsive Force of Upper Limbs and its Relationship to Swim Velocity in the Butterfly Stroke.

The aims of this study were to: (1) verify the sex effect; (2) assess upper limb asymmetry in anthropometrics and propulsive force variables; and (3) identify the main determinants of butterfly swim velocity based on a set of anthropometrics, kinematics, and propulsive force variables. Twenty swimmers (10 males: 15.40±0.30 years; 10 females: 14.43±0.23 years) at the national level were recruited for analysis. A set of anthropometrics, kinematics, and propulsive force variables were measured. Overall, a significant sex effect was verified (p≤0.05). Non-significant differences between upper-limbs were noted for males and females in all variables, except for the dF in males (t=-2.66, p=0.026, d=0.66). Stroke frequency presented the highest contribution, where a one unit increase in the stroke frequency imposed an increase of 0.375 m·s-1 (95CI: 0.105;0.645, p=0.010) in the swim velocity. The swim velocity was predicted by the mean propulsive force, intra-cyclic variation of the swim velocity, and stroke frequency. Overall, swimmers exhibit non-significant differences in the variables assessed. Swim velocity in the butterfly stroke was determined by an interaction of propulsive force and kinematic variables in young swimmers.

Effects of Match Location, Quality of Opposition and Match Outcome on Match Running Performance in a Portuguese Professional Football Team.

The aim of this study was to analyze the effects of match location, quality of opposition and match outcome on match running performance according to playing position in a Portuguese professional football team. Twenty-three male professional football players were monitored from eighteen Portuguese Football League matches during the 2019-2020 season. Global positioning system technology (GPS) was used to collect time-motion data. The match running performance was obtained from five playing positions: central defenders (CD), fullbacks (FB), central midfielders (CM), wide midfielders (WM) and forwards (FW). Match running performance was analyzed within specific position and contextual factors using one-way analysis of variance (ANOVA) for repeated measures, standardized (Cohen) differences and smallest worthwhile change. CM and WM players covered significantly greater total distance (F = 15.45, p = 0.000, η2 = 0.334) and average speed (F = 12.79, p < 0.001, η2 = 0.294). WM and FB players covered higher distances at high-speed running (F = 16.93, p = 0.000, η2 = 0.355) and sprinting (F = 13.49; p < 0.001, η2 = 0.305). WM players covered the highest number of accelerations (F = 4.69, p < 0.001, η2 = 0.132) and decelerations (F = 12.21, p < 0.001, η2 = 0.284). The match running performance was influenced by match location (d = 0.06-2.04; CI: -0.42-2.31; SWC = 0.01-1.10), quality of opposition (d = 0.13-2.14; CI: -0.02-2.60; SWC = 0.01-1.55) and match outcome (d = 0.01-2.49; CI: -0.01-2.31; SWC = 0.01-0.35). Contextual factors influenced the match running performance with differential effects between playing positions. This study provides the first report about the contextual influence on match running performance in a Portuguese professional football team. Future research should also integrate tactical and technical key indicators when analyzing the match-related contextual influence on match running performance.

Relationship between fear of falling and balance factors in healthy elderly women: A confirmatory analysis.

The aim of this study was to develop a confirmatory model, using structural equation modeling, to describe and explain the fear of falling in elderly women. Forty-one participants (67.69 ± 5.30 years) were selected to test a theoretical model. The final model revealed that the fear of falling is related to impaired balance (dynamic and static). Strength has a positive effect on both dynamic and static balance. Strength depends on bone mineral density. In conclusion, more strength and bone mineral density and better body balance tend to decrease the fear of falling.

The Aerodynamics and Energy Cost Assessment of an Able-Bodied Cyclist and Amputated Models by Computer Fluid Dynamics.

Background and Objectives: The aim of this study was to assess and compare the drag and energy cost of three cyclists assessed by computational fluid dynamics (CFD) and analytical procedures. Materials and methods: A transradial (Tr) and transtibial (Tt) were compared to a full-body cyclist at different speeds. An elite male cyclist with 65 kg of mass and 1.72 m of height volunteered for this research with his competition cloths, helmet and bicycle with 5 kg of mass. A 3D model of the bicycle and cyclist in the upright position was obtained for numerical simulations. Upon that, two more models were created, simulating elbow and knee-disarticulated athletes. Numerical simulations by computational fluid dynamics and analytical procedures were computed to assess drag and energy cost, respectively. Results: One-Way ANOVA presented no significant differences between cyclists for drag (F = 0.041; p = 0.960; η2 = 0.002) and energy cost (F = 0.42; p = 0.908; η2 = 0.002). Linear regression presented a very high adjustment for absolute drag values between able-bodied and Tr (R2 = 1.000; Ra2 = 1.000; SEE = 0.200) and Tt (R2 = 1.00; Ra2 = 1.000; SEE = 0.160). The linear regression for energy cost presented a very high adjustment for absolute values between able-bodied and Tr (R2 = 1.000; Ra2 = 1.000; SEE = 0.570) and Tt (R2 = 1.00; Ra2 = 1.00; SEE = 0.778). Conclusions: This study suggests that drag and energy cost was lower in the able-bodied, followed by the Tr and Tt cyclists.

Comparison of the Start, Turn and Finish Performance of Elite Swimmers in 100 m and 200 m Races.

The main aim of this study was to compare the start, turn, and finish performance of 100 m and 200 m events in the four swimming strokes in elite swimmers of both sexes. The performances of all 128 finalists (64 males and 64 females) of the 100 m, and 200 m events at a major championship were analyzed. A set of variables related to the start, turn, and finish were assessed. In the start a significant and moderate race effect was verified in both sexes (100 m vs 200 m). It was highest in butterfly events (males: Δ = 9.81%, p = 0.046, η2 = 0.60; females: Δ = 7.96%, p < 0.001, η2 = 0.75). In the turn a significant and moderate-strong race effect was verified in all strokes in both sexes, the highest being in butterfly (males: Δ = 12.26%, p < 0.001, η2 = 0.93; females: Δ = 10.74%, p < 0.001, η2 = 0.92). The finish had a significant and moderate race effect in butterfly and in breaststroke (females). The underwater variables were found to be the main contributors to a faster start. Over the turn, key determinants were the surface variables. As for the finish, mixed results were observed. It can be suggested that the underwater profile was the main determinant in starting, whereas the surface profile was the main determinant in turning. Therefore, coaches are advised to focus on such race phases to enhance the total race time.

Schoolbag weight carriage in Portuguese children and adolescents: a cross-sectional study comparing possible influencing factors.

BACKGROUND: Schoolbags and the consequences of carrying them, particularly those associated with overload, are often studied as a health concern. Modifications in gait and posture were reported when children carried loads that corresponded to more than 10% of their body weight (BW). The aims of this study were to verify the load that is carried by Portuguese students and how it is influenced by factors such as school grade, school schedule, lunch site, physical education, sex and body mass index (BMI). Acquiring a more specific knowledge of the Portuguese context and understanding the influence of these factors may allow us to generate proposals to control them in ways that benefit students. METHODS: The load carried by students in the 5th grade (10.6 ± 0.4 years) and 9th grade (14.7 ± 0.6 years) were weighed with a luggage scale on all days of the week, resulting in 680 evaluations. Data related to the school day were also collected, such as the student's lunch site, how he or she got to school and his or her school schedule for that day. Individual height and weight were also assessed. RESULTS: The 5th grade students carried greater loads than the 9th grade students, resulting in a substantial difference relative to their BW. The school loads of the 5th grade students were mostly greater than 10% of their BWs. Girls tended to carry heavier loads than boys, and overweight students also tended to carry heavier loads. Students who could eat lunch at home carried less weight, and on physical education days, the total load carried increased, but the backpacks of the 5th grade students were lighter. CONCLUSIONS: The results of the current study describe excessive schoolbag weight among Portuguese students and expound on some of the factors that influence it, which can help researchers and professionals design a solution to decrease children's schoolbag loads.

Brief Review: Effects of Isometric Strength Training on Strength and Dynamic Performance.

This review used a narrative summary of findings from studies that focused on isometric strength training (IST), covering the training considerations that affect strength adaptations and its effects on sports related dynamic performances. IST has been shown to induce less fatigue and resulted in superior joint angle specific strength than dynamic strength training, and benefited sports related dynamic performances such as running, jumping and cycling. IST may be included into athletes' training regime to avoid getting overly fatigue while still acquiring positive neuromuscular adaptations; to improve the strength at a biomechanically disadvantaged joint position of a specific movement; to improve sports specific movements that require mainly isometric contraction; and when athletes have limited mobility due to injuries. To increase muscle hypertrophy, IST should be performed at 70-75% of maximum voluntary contraction (MVC) with sustained contraction of 3-30 s per repetition, and total contraction duration of>80-150 s per session for>36 sessions. To increase maximum strength, IST should be performed at 80-100% MVC with sustained contraction of 1-5 s, and total contraction time of 30-90 s per session, while adopting multiple joint angles or targeted joint angle. Performing IST in a ballistic manner can maximize the improvement of rate of force development.

Assessment of passive drag in swimming by numerical simulation and analytical procedure.

The aim was to compare the passive drag-gliding underwater by a numerical simulation and an analytical procedure. An Olympic swimmer was scanned by computer tomography and modelled gliding at a 0.75-m depth in the streamlined position. Steady-state computer fluid dynamics (CFD) analyses were performed on Fluent. A set of analytical procedures was selected concurrently. Friction drag (Df), pressure drag (Dpr), total passive drag force (Df+pr) and drag coefficient (CD) were computed between 1.3 and 2.5 m · s-1 by both techniques. Df+pr ranged from 45.44 to 144.06 N with CFD, from 46.03 to 167.06 N with the analytical procedure (differences: from 1.28% to 13.77%). CD ranged between 0.698 and 0.622 by CFD, 0.657 and 0.644 by analytical procedures (differences: 0.40-6.30%). Linear regression models showed a very high association for Df+pr plotted in absolute values (R2 = 0.98) and after log-log transformation (R2 = 0.99). The CD also obtained a very high adjustment for both absolute (R2 = 0.97) and log-log plots (R2 = 0.97). The bias for the Df+pr was 8.37 N and 0.076 N after logarithmic transformation. Df represented between 15.97% and 18.82% of the Df+pr by the CFD, 14.66% and 16.21% by the analytical procedures. Therefore, despite the bias, analytical procedures offer a feasible way of gathering insight on one's hydrodynamics characteristics.

Contribution of limbs' actions to the four competitive swimming strokes: a nonlinear approach.

The aim of our study was to assess the effect of the limbs' actions on the nonlinear properties of the four competitive swimming strokes. Forty-nine swimmers performed all-out sprints at front-crawl, backstroke, breaststroke and butterfly, each one at full stroke (FS), only the arms' stroke (AS), and only leg kicking (LK), in a total of 12 bouts, 6 per day. A speedo-meter cable was attached to the swimmer's hip, to collect the speed-time raw data (f = 50Hz). Velocity, speed fluctuation, sample entropy and fractal dimension were derived from the speed-time series. Significant and moderate-strong effects were noted for both stroke and condition in all variables in the study (p ≤ 0.001; 0,560<η2 < 0,952). The four competitive strokes and their three conditions exhibited nonlinear properties. The swimming pattern was less complex and more predictable for LK in comparison to AS and FS. Breaststroke and butterfly have more complex but more predictable patterns than backstroke and front-crawl.

The aging influence on cardiorespiratory, metabolic, and energy expenditure adaptations in head-out aquatic exercises: Differences between young and elderly women.

The purpose of this study was to: (1) establish the relationship between acute physiological responses and musical cadence; and (2) compare physiologic responses between young and older women. Eighteen older (mean = 65.06 ± 5.77 years) and 19 young (mean = 22.16 ± 2.63 years) women underwent an intermittent and progressive protocol performing the head-out aquatic exercise the "rocking horse." Results showed that older women demonstrated lower mean heart rate, blood lactate concentration (bLa), and oxygen uptake (VO2) at rest. Hierarchical linear modeling showed that variations in the rating of perceived effort and individual metabolic equivalent of task did not differ significantly by age group. However, during exercise, physiological responses of younger women were significantly different than for older women: in mean values, for each increased musical beat per minute, mean bLa was 0.003 mmol/l, VO2 was 0.024 ml/kg/min, and energy expenditure was 0.0001 kcal/kg/min higher for younger women. This study shows that increases in musical cadence increased the cardiorespiratory, metabolic, and energy expenditure responses. However, these responses during increasing intensity seemed to differ between young and older women, with lower values for the elderly group, when performing head-out aquatic exercises.