VO₂ kinetics and metabolic contributions during full and upper body extreme swimming intensity

Sprinting to the top: comparing quality of distance variety and specialization between swimmers and runners

Objectives

To compare performance progression and variety in race distances of comparable lengths (timewise) between pool swimming and track running. Quality of within-sport variety was determined as the performance differences between individual athletes' main and secondary race distances across (top-) elite and (highly-) trained swimmers and runners.

Methods

A total of 3,827,947 race times were used to calculate performance points (race times relative to the world record) for freestyle swimmers (n = 12,588 males and n = 7,561 females) and track runners (n = 9,230 males and n = 5,841 females). Athletes were ranked based on their personal best at peak performance age, then annual best times were retrospectively traced throughout adolescence.

Results

Performance of world-class swimmers differentiates at an earlier age from their lower ranked peers (15-16 vs. 17-20 year age categories, P < 0.05), but also plateaus earlier towards senior age compared to runners (19-20 vs. 23 + year age category, P < 0.05), respectively. Performance development of swimmers shows a logarithmic pattern, while runners develop linearly. While swimmers compete in more secondary race distances (larger within-sport variety), runners specialize in either sprint, middle- or long-distance early in their career and compete in only 2, 4 or 3 other race distances, respectively. In both sports, sprinters specialize the most (P < 0.05). Distance-variety of middle-distance swimmers covers more longer rather than sprint race distances. Therefore, at peak performance age, (top-) elite female 200 m swimmers show significantly slower sprint performances, i.e., 50 m (P < 0.001) and 100 m (P < 0.001), but not long-distance performances, i.e., 800 m (P = 0.99) and 1,500 m (P = 0.99). In contrast, (top-) elite female 800 m middle-distance runners show significantly slower performances in all their secondary race distances (P < 0.001). (Top-) elite female athletes specialize more than (highly-) trained athletes in both sports (P < 0.05).

Conclusions

The comparison to track running and lower ranked swimmers, the early performance plateau towards senior age, and the maintenance of a large within-sport distance variety indicates that (top-) elite sprint swimmers benefit from greater within-sport specialization.

Training zones in competitive swimming: a biophysical approach

Since swimming performance depends on both physical conditioning and technical proficiency, training zones should be built based on physiology and biomechanics inputs to dispose of structured and effective training programs. This paper presents a zone-based swimming training, supported by the oxygen uptake (V ˙ O2) kinetics at low, moderate, heavy, severe and extreme intensities concurrently with lactate and heart rate values. Since technique is vital for efficiently moving through the water, upper limbs frequency and length should also be targeted during the workouts. The index of coordination was also added to our proposal since upper limbs synchronization is a key technical factor. To better establish and characterize a wide range of swimming intensities, the training methods and corresponding contents that better fit each training zone will be suggested. It will be shown that when under/at the anaerobic threshold (at low-to-moderate intensities), swimmers are at homeostasis and can maintain stable internal and external load indicators. However, above that boundary (at heavy and severe intensities), the physiological stable state is no longer observed and the anaerobic metabolism starts contributing significantly, with a technical degradation being more evident when performing near/at the V ˙ O2max intensity. Then, when performing above aerobic power, on typical anaerobic intensities, V ˙ O2 kinetics presents a very evident fast rise, ending abruptly due to exhaustion caused by muscle acidosis. This overall knowledge allows advancing toward more objective training programs and highlights the importance of systematic training control and swimmers' evaluation and advice.

Effect of the Fran CrossFit Workout on Oxygen Uptake Kinetics, Energetics, and Postexercise Muscle Function in Trained CrossFitters

PURPOSE

Fran is one of the most popular CrossFit benchmark workouts used to control CrossFitters' improvements. Detailed physiological characterization of Fran is needed for a more specific evaluation of CrossFitters' training performance improvements. The aim of the study was to analyze the oxygen uptake (V˙O2) kinetics and characterize the energy system contributions and the degree of postexercise fatigue of the unbroken Fran.

METHODS

Twenty trained CrossFitters performed Fran at maximal exertion. V˙O2 and heart-rate kinetics were assessed at baseline and during and post-Fran. Blood lactate and glucose concentrations and muscular fatigue were measured at baseline and in the recovery period.

RESULTS

A marked increase in V˙O2 kinetics was observed at the beginning of Fran, remaining elevated until the end (V˙O2peak: 49.2 [3.7] mL·kg-1·min-1, V˙O2 amplitude: 35.8 [5.2] mL·kg-1·min-1, time delay: 4.7 [2.5] s and time constant: 23.7 [11.1] s; mean [SD]). Aerobic, anaerobic lactic, and alactic pathways accounted for 62% (4%), 26% (4%), and 12% (2%) of energy contribution. Reduction in muscle function in jumping ability (jump height: 8% [6%], peak force: 6% [4%], and maximum velocity: 4% [2%]) and plank prone test (46% [20%]) was observed in the recovery period.

CONCLUSIONS

The Fran unbroken workout is a high-intensity effort associated with an elevated metabolic response. This pattern of energy response highlights the primary contribution of aerobic energy metabolism, even during short and very intense CrossFit workouts, and that recovery can take >24 hours due to cumulative fatigue.

Mechanics and Energetic Analysis of Rowing with Big Blades with Randall Foils

Empirical observations support that the addition of a plastic strip - also known as Randall foils - on the top edge of a rowing blade improves rowing efficiency during the cycle propulsive phase. The aim of the current study was to analyze the effect of using big blades with and without Randall foils on rowing performance. Twenty experienced rowers performed two 90 s tethered rowing bouts (with and without Randall foils) to assess their impact on force production and physiologic variables. All tests were randomized and a repeated measure design was used to compare experimental conditions. Higher values of peak and mean peak forces (479.4±134.7 vs. 423.2±153.0, d=0.83 and 376.5±101.4 vs. 337.1±113.3 N, d=0.68), peak oxygen uptake (47.9±7.5 vs. 45.3±7.3 mL∙kg-1∙min-1, d=0.19), peak blood lactate concentration (7.9±1.6 vs. 6.9±1.7 mmol∙L-1, d=0.16), blood lactate increasing speed (0.08±0.01 vs. 0.07±0.06 [(mmol·L-1)·s-1], d=0.27) and lactic anaerobic energy (27.4±7.9 vs. 23.4±8.1 kJ, d=0.23) were found for big blades with vs. without Randall foils, p<0.05. The current data suggest that the Randall foils can positively affect rowing performance.

Oxygen uptake kinetics and biological age in relation to pulling force and 400-m front crawl performance in young swimmers

Background: The study aimed to assess differences in the biological age (BA) of 13-year-old swimmers and show their ability, as biologically younger-late mature or older-early mature, to develop fast 60-s oxygen uptake (V ˙ O 2 ) kinetics and tethered swimming strength. Furthermore, the interplay between swimming strength, V ˙ O 2 , and 400-m front crawl race performance was examined. Methods: The study involved 36 competitive young male swimmers (metrical age: 12.9 ± 0.56 years). Depending on BA examination, the group was divided into early-mature (BA: 15.8 ± 1.18 years, n = 13) and late-mature (BA: 12.9 ± 0.60 years, n = 23) participants, especially for the purpose of comparing tethered swimming indices, i.e., average values of force (F ave) and V ˙ O 2 (breath-by-breath analysis) kinetic indices, measured simultaneously in 1-min tethered front crawl swimming. From the 400-m racing stroke rate, stroke length kinematics was retrieved. Results: In the 1-min tethered front crawl test, early-mature swimmers obtained higher results of absolute values of V ˙ O 2 and F ave. Conversely, when V ˙ O 2 was present relatively to body mass and pulling force (in ml∙min-1∙kg-1∙N-1), late-mature swimmers showed higher O 2 relative usage. Late-mature swimmers generally exhibited a slower increase in V ˙ O 2 during the first 30 s of 60 s. V ˙ O 2 , F ave, BA, and basic swimming kinematic stroke length were significantly interrelated and influenced 400-m swimming performance. Conclusion: The 1-min tethered swimming test revealed significant differences in the homogeneous calendar age/heterogeneous BA group of swimmers. These were distinguished by the higher level of V ˙ O 2 kinetics and pulling force in early-mature individuals and lower efficiency per unit of body mass per unit of force aerobic system in late-mature peers. The higher V ˙ O 2 kinetics and tethered swimming force were further translated into 400-m front crawl speed and stroke length kinematics.

Swimming sprint performance depends on upper/lower limbs strength and swimmers level

Swimming performance is likely influenced by strength, but differences between butterfly, backstroke, breaststroke and front crawl, as well as between novice and expert swimmers, are unclear. We have examined the associations between sprint performances, upper and lower limb strength, and anthropometric characteristics in 14 (six males and eight females) non-elite and 16 (nine males and seven females) elite-level swimmers. After an anthropometric characterisation, participants performed four 25 m maximal swims (one per technique) with 10 min intervals, right and left shoulder flexion/extension isokinetic testing at 90 and 300º/s angular velocities and three countermovement jumps. Pearson correlation analysis showed that sprint times were moderate-largely negatively correlated with upper and lower limb strength and power (r ± 95%CI = 0.39 ± 0.26-0.77 ± 0.13, p < 0.05). Elite swimmers higher strength levels were associated with longer stroke length in butterfly and front crawl, and with higher stroke rate in backstroke and breaststroke (r ± 95%CI = 0.37 ± 0.32-0.68 ± 0.21; p < 0.05). Butterfly, backstroke and front crawl sprint times were moderate-largely negatively related with arm span (r ± 95%CI = 0.37 ± 0.26, 0.39 ± 0.25 and 0.69 ± 0.17, p < 0.05). The predictive model indicated that higher dry-land strength values distinguished elite from non-elite swimmers (r2 = 0.67-0.81; p < 0.001). This association was not observed per performance level and per sex, confirming that sprint swimming performance levels can be differentiated by dry-land strength testing.

Reliability and Validity of a Flume-Based Maximal Oxygen Uptake Swimming Test

A mode-specific swimming protocol to assess maximal aerobic uptake (VO₂max_sw) is vital to accurately evaluate swimming performance. A need exists for reliable and valid swimming protocols that assess VO₂max_sw in a flume environment. The purpose was to assess: (a) reliability and (b) "performance" validity of a VO₂max_sw flume protocol using the 457-m freestyle pool performance swim (PS) test as the criterion. Nineteen males (n = 9) and females (n = 10) (age, 28.5 ± 8.3 years.; height, 174.7 ± 8.2 cm; mass, 72.9 ± 12.5 kg; %body fat, 21.4 ± 5.9) performed two flume VO₂max_sw tests (VO₂max_swA and VO₂max_swB) and one PS test [457 m (469.4 ± 94.7 s)]. For test-retest reliability (Trials A vs. B), moderately strong relationships were established for VO₂max_sw (mL·kg^-1·min^-1)(r= 0.628, p = 0.002), O₂pulse (mL O₂·beat^-1)(r = 0.502, p = 0.014), VEmax (L·min^-1) (r = 0.671, p = 0.001), final test time (sec) (0.608, p = 0.004), and immediate post-test blood lactate (IPE (BLa)) (0.716, p = 0.001). For performance validity, moderately strong relationships (p < 0.05) were found between VO₂max_swA (r =-0.648, p = 0.005), O₂pulse (r= -0.623, p = 0.008), VEmax (r = -0.509 p = 0.037), and 457-m swim times. The swimming flume protocol examined is a reliable and valid assessment of VO₂max_sw., and offers an alternative for military, open water, or those seeking complementary forms of training to improve swimming performance.

Usefulness of V˙O2 Kinetics and Biomechanical Parameters as Predictors of Athlete's Performance in 800 m Running Race

Incremental tests to exhaustion have been usually employed as the “gold standard” to establish the fitness level of athletes. However, during real competition in many sport disciplines, exertion is not characterized by an increasing effort until failure. The purpose of this preliminary study was to add new evidence regarding the usability of parameters obtained from an on-field testing in 800 m running athletes. V˙O2 kinetics (mean, amplitude, phase time, and phase start time) and biomechanical parameters (velocity, stride frequency, and stride length) were analyzed in eight athletes during a maximal 800 m running race test. Our results showed that only the peak of blood lactate concentration after the 800 m test was correlated with the race time (p = 0.047). The race time was positively associated with both the phase duration and phase start time (all p-values < 0.05). Conversely, race time was negatively correlated with velocity, stride frequency, and amplitude (p-values < 0.05). Our results reveal that jointly studying the V˙O2 kinetics and biomechanical parameters during a maximal 800 m running race test is a useful tool to predict the athlete’s upcoming performance and improve the planning and control of the training process of 800 m running athletes.

Lower fatigue and faster recovery of ultra-short race pace swimming training sessions

Ultra-short race-pace training (USRPT) is a high-intensity training modality used in swimming for the development of specific race-technique. However, there is little information about the fatigue associated to this modality. In a crossover design, acute responses of two volume-equated sessions (1000-m) were compared on 14 national swimmers: i) USRPT: 20×50-m; ii) RPT: 10×100-m. Both protocols followed an equivalent work-recovery ratio (1:1) based on individual 200-m race-pace. The swimming times and the arm-strokes count were monitored on each set and compared by mixed-models. Blood lactate [La^-] and countermovement jump-height (CMJ) were compared within and between conditions 2 and 5 min after the protocols. The last bouts in RPT were 1.5-3% slower than the target pace, entailing an arm-strokes increase of ~0.22 for every second increase in swimming time. USRPT produced lower [La^-] ([Mean ± standard deviation], 2 min: 8.2±2.4 [p = 0.021]; 5 min: 6.9±2.8 mM/L [p = 0.008]), than RPT (2 min: 10.9±2.3; 5 min: 9.9±2.4 mM/L). CMJ was lowered at min 2 after RPT (-11.09%) and USRPT (-5.89%), but returned to baseline in USRPT at min 5 of recovery (4.07%). In conclusion, lower fatigue and better recovery were achieved during USRPT compared to traditional high-volume set.

Manipulation of Stroke Rate in Swimming: Effects on Oxygen Uptake Kinetics

The study aimed to assess the effect of different front crawl stroke rates (SRs) in the oxygen uptake (̇VO₂) kinetics and ̇VO₂ peak, the total time to exhaustion (TTE), and blood lactate concentration ([La]) at 95% of the 400-m front crawl test (T400) mean speed (S400). Twelve endurance swimmers performed a T400 and four trials at 95% of the S400: (i) free SR, (ii) fixed SR (100% of the average free SR trial), (iii) reduced SR (90% of the average free SR trial), and (iv) increased SR (110% of the average free SR trial). ̇VO₂ was accessed continuously with breath-by-breath analysis. The results highlighted: (i) the time constant at increased SR (13.3±4.2 s) was lower than in the reduced SR condition (19.5±2.6 s); (ii) the amplitude of the primary phase of ̇VO₂ kinetics in the fixed SR (44.0±5.8 ml·kg^-1·min^-1) was higher than in the increased SR condition (39.5±6.4 ml·kg^-1·min^-1); and (iii) TTE was lower in the fixed SR (396.1±189.7 s) than the increased SR condition (743.0±340.0 s). The results indicate that controlled SR could be considered a swimming training strategy, focusing on physiological parameters overload.

V ˙ O 2 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 V ˙ O 2 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 ± 0.9 years 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 V ˙ O 2 : 31-60, 41-60, and 51-60 and F _max, F _ave , and I _ave of tethered swimming, while 41-60 and 51-60 V ˙ O 2 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 V ˙ O 2 fast is essential for a swimmer's energy production at short- and middle-distance events. Reaching a high level of V ˙ O 2 significantly determines tethered strength and swimming kinematics. The level of V ˙ O 2 influences the maintenance of a proper pulling force and the stroke technique of front crawl swimming in young male swimmers.

Associations Between Selected Biological Features and Absolute and Relative Swimming Performance of Prepubescent Boys Over a 3-Year Swimming Training Program: A Longitudinal Study

The study aimed to investigate the effect of 3-year swimming training on selected biological variables in prepubescent male swimmers and to determine the best predictors of absolute (VS_a) and relative (VS_r) swimming velocity for 50 m and 400 m front crawl. Twenty-one 10-year old boys subjected to endurance swimming training (4 x 70 min per week) and 18 boys consisting a control group were assessed semi-annually for basic anthropometric and respiratory characteristics, breath-hold time (BHT), VO_2max, leg explosiveness (HJ), and abdominal strength endurance (ASE). After three years of training, BHT (p < 0.001), VO_2max (p < 0.01), HJ (p < 0.01) and ASE (p < 0.01) were greater in the swimmers than in the controls. VS_a and VS_r expressed as a percentage of baseline velocity increased more for the 50 m than for the 400 m distance (p < 0.001 and p < 0.01, respectively). The 50 m VS_a and VS_r positively correlated with those obtained for the distance of 400 m (in both cases p < 0.001). Baseline VS_a was negatively correlated with the increase in absolute swimming velocity for both distances (50 m: r = -0.684, p < 0.001 and 400 m: r = -0.673, p < 0.001). The best predictors of VS_a for 50 m and 400 m front crawl were HJ (r₂ = 0.388; p < 0.001) and VO_2max (r₂ = 0.333; p < 0.001), respectively. The key predictors of VS_r for both distances were age (50 m: r² = 0.340, p < 0.001 and 400 m: r² = 0.207, p < 0.001) and, after excluding it from analysis, HJ (50 m: r² = 0.176, p < 0.001 and 400 m: r² = 0.104, p < 0.001). These results suggest that regardless of prepubescent boys’ initial abilities and exercise capacity, improvement in their swimming performance mainly depends on increases in power and neuromuscular coordination.

Biophysical Impact of 5-Week Training Cessation on Sprint Swimming Performance

PURPOSE

To assess changes in swimming performance, anthropometrics, kinematics, energetics, and strength after 5-week training cessation.

METHODS

Twenty-one trained and highly trained swimmers (13 males: 17.4 [3.1] y; 50-m front crawl 463 [77] FINA points; 8 females: 16.7 [1.7] y; 50-m front crawl 535 [48] FINA points) performed a 50-m front-crawl all-out swim test, dryland and pool-based strength tests, and 10-, 15-, 20-, and 25-m front-crawl all-out efforts for anaerobic critical velocity assessment before and after a 5-week training cessation. Heart rate and oxygen uptake (V˙O2) were continuously measured before and after the 50-m swim test (off-kinetics).

RESULTS

Performance was impaired 1.9% (0.54 s) for males (P = .007, d = 0.91) and 2.9% (0.89 s) for females (P = .033, d = 0.93). Neither the anthropometrical changes (males: r2 = .516, P = .077; females: r2 = .096, P = .930) nor the physical activities that each participant performed during the off-season (males: r2 = .060, P = .900; females: r2 = .250, P = .734) attenuated performance impairments. Stroke rate and clean swimming speed decreased (P < .05), despite similar stroke length and stroke index (P > .05). Blood lactate concentrations remained similar (P > .05), but V˙O2 peak decreased in females (P = .04, d = 0.85). Both sexes showed higher heart rate before and after the 50-m swim test after 5 weeks (P < .05). Anaerobic metabolic power deterioration was only observed in males (P = .035, d = 0.65). Lower in-water force during tethered swimming at zero speed was observed in males (P = .033, d = 0.69). Regarding dryland strength, lower-body impairments were observed for males, while females showed upper-body impairments (P < .05).

CONCLUSIONS

A 5-week training cessation yielded higher heart rate in the 50-m front crawl, anaerobic pathways, and dryland strength impairments. Coaches should find alternatives to minimize detraining effects during the off-season.

Physiological Responses and Stroke Variables during Arm Stroke Swimming Using Critical Stroke Rate in Competitive Swimmers

The current study examined the physiological responses and stroke variables at critical stroke rate (CSR), 105% CSR, and 110% CSR in order to utilize CSR for prescription arm stroke swimming. Nine male national-level collegiate swimmers performed an all-out 200 m and 400 m for determining the CSR. Participants performed three sets of 6 × 100 m (with 10 s of rest between each bout), the stroke rate for each set was enforced at CSR, 105% CSR, and 110% CSR. Mean swimming velocity, heart rate, and rate of perceived exertion were found to increase with each set (p < 0.05). Blood lactate concentration did not differ between the CSR and the 105% CSR (3.3 ± 1.4 vs. 3.5 ± 1.5 mmol/L) but was higher in 110% CSR (5.1 ± 1.6 mmol/L) than in the other two sets (p < 0.05). There was no difference in the stroke rate between all bouts in each set, and the stroke length did not change from the second to sixth bout in each set. This study suggested that training intensity for CSR and 105% CSR correspond to threshold level, and 110% CSR corresponds to high-intensity training level. It was also suggested that training in the CSR−110% CSR range could be performed without regard to SL reduction.

Relevance of a Sprint Interval Swim Training Set to the 100-Meter Freestyle Event Based on Blood Lactate and Kinematic Variables

Sprint interval training (SIT) sets are commonly used by coaches in the training routine of swimmers competing in short-distance events; however, data regarding their relevance to competitive events are scarce. The aim of this study was to examine whether performance variables differed or correlated between a 4 × 50-m maximal swimming set (with a work-to-rest ratio of 1:4) and the 100-m freestyle event. Eleven male and 16 female competitive swimmers aged 16.1 ± 1.1 years participated in the study. All swimmers trained at least six times a week and had training experience of more than 4 years. They completed the two freestyle tests on different days, in random and counterbalanced order. In each test, speed, blood lactate, stroke rate (SR), and stroke index (SI) were measured. Speed, blood lactate, and SR were higher at the 4 × 50 m compared to the 100 m and were positively correlated between tests (p < 0.001). The SI did not differ significantly, but was positively correlated between tests. Males were faster and had a higher SI than females, but genders did not differ in lactate. Since performance variables were better in the SIT set and correlated with those in the 100-m bout, we suggest that the 4 × 50-m set can be used to improve performance in the 100-m freestyle event. Moreover, this set can help coaches identify which swimmers will swim fastest in the event.

Stroking Rates of Open Water Swimmers during the 2019 FINA World Swimming Championships

The aim of the present research was to examine the stroking rate (SR) values of successful and non-successful swimmers in the 10 km and 25 km races of the FINA 2019 World Swimming Championships. Data from 175 participants (95 men and 80 female) were classified according to their finishing positions. There were no meaningful differences in the overall SR values displayed by successful or non-successful participants during the 10 km and 25 km open water races of the FINA 2019 World Swimming Championships. However, there were changes in the SR throughout the races that depended on the swimmer’s performance group and gender. Successful swimmers in the 10 km event typically displayed even SR in the first 5 km but, unlike the remaining performance groups, increased their SR at some point in the second 5 km of the race. In the 25 km race, successful female swimmers presented an even SR profile for most of the race, whereas successful males presented a more variable profile. Nevertheless, no relationships between partial or average SR and finishing positions occurred, either in the 10 km or in the 25 km race. Changes in the SR values should be included in the race plan of open water swimmers according to tactical and pacing strategies.

Change in short distance swimming performance following inspiratory muscle fatigue

BACKGROUND

Inspiratory muscle fatigue (IMF) may impair performance in a subsequent exercise. A few studies have reported that IMF decreased swimming performance in sub-maximal intensity or severe intensity domain. However, the impact of IMF on high-intensity short-duration swimming is not clear. The purpose of this study was to clarify the effect of pre-induced IMF on extreme intensity domain swimming.

METHODS

Seven male competitive swimmers swam two 100-m all-out front crawl swimming trials with and without pre-induced IMF. Maximal inspiratory and expiratory mouth pressure (PImax and PEmax, respectively) was used as indicators of inspiratory and expiratory muscle strength before and after swimming, and stroke parameters during swimming were measured. IMF was achieved by having the subjects breathe against an inspiratory pressure threshold load while generating 40% of their predetermined PImax for 10 min.

RESULTS

After the induction of IMF, swimming time (55.94 ± 1.15 s) was significantly slower compared with that in control swimming without IMF (54.09 ± 0.91 s) (p < 0.05). During swimming followed IMF, a significant decrease in stroke rate and a significant increase in stroke length were observed in the latter half of the 100-m swimming trial. In addition, the sense of dyspnea was significantly higher in swimming in the IMF condition than in control condition.

CONCLUSIONS

IMF prior to swimming negatively affects swimming performance in the extreme intensity domain. It is suggested that due to the dual use of respiration and generate propulsion in accessory respiratory muscles, IMF affected swimmers' ability to maintain swimming velocity.

Impact of COVID-19 on Swimming Training: Practical Recommendations during Home Confinement/Isolation

The COVID-19 pandemic has had severe effects on communities globally, leading to significant restrictions on all aspects of society, including in sports. Several significant decisions were made to postpone or cancel major swimming events by FINA (Fédération Internationale de Natation). Swimmers were no longer allowed to continue their usual training in swimming pools and were confined to their homes. These unusual circumstances may represent a good opportunity to strengthen different areas of swimmer preparation and potentially enhance performance when resuming regular aquatic training. We searched major databases for relevant information, and the present article provides practical information on home-based training for swimmers of all ages. The COVID-19 crisis and its consequences on the swimming community have created a myriad of challenges for swimmers around the world, including maintaining their fitness level and preparing to return optimally and safely to pool training and competitions. Unfortunately, the mental consequences that might arise after the pandemic may also have an impact. We strongly recommend encouraging the swimmers to consider quarantine as an opportunity for development in specific areas of preparation and learn how to best cope with this special situation of self-isolation and/or "physical distancing" for their mental health and in case a similar situation is faced again in the future.

Pre-exercise skin temperature evolution is not related with 100 m front crawl performance

During the transition between warm-up and competition there is a change in core, muscle and (eventually) skin temperature that may affect swimming performance. We have aimed to assess skin temperature evolution during transition phases of different durations before a typical front crawl effort and to investigate its relationship with performance. Following a standardized warm-up, nine adolescent male swimmers performed three maximal randomized 100 m maximum front crawl trials after 10, 20 and 45 min transition phases. Skin temperature, performance (time, stroke frequency, length and index, and propelling efficiency), heart rate, lactate and perceived effort were assessed. Data showed a skin temperature log increase over time (R² > 0.96, p < 0.01) without differences from the 15 min with the following instants. Performance and psychophysiological variables were similar between transition phases. However, skin temperature at the end of the transition periods, i.e., just before the 100 m trials, was lower in the 10 min than the 20 and 45 min transitions (32.0 ± 0.6 vs 33.0 ± 0.4 and 33.5 ± 0.5 °C, respectively). The main finding was that no relevant relationships were observed between pre-test skin temperature and performance times (|r| < 0.6, p > 0.05) for the studied transition phases. We have concluded that transitions longer than 10 min will not present thermal changes and that, within the physiologic limits studied, pre-exercise skin temperature does not influence swimming performance.

Impact of Mild Hypohydration on 100 m Front Crawl Performance and Starting Block Peak Force Production in Competitive University-Level Swimmers

Unstructured, ad libitum drinking may predispose some athletes to start exercise already slightly hypohydrated (decreased body water). The impact of pre-exercise mild hypohydration on subsequent swimming performance is still unknown. Hence, the goal of this study was to examine its effect on peak force production on the starting block and 100 m front crawl swimming performance in competitive university-level swimmers. At least one hour after having been passively exposed to heat where a body mass loss of 1.5% was induced or euhydration (normal body water) maintained, nine participants (age: 22 ± 2 years) underwent an assessment of their peak force production on the starting block and 100 m front crawl performance. One hour following hypohydration, rectal temperature had returned to baseline in each condition. Urine osmolality and specific gravity were higher (p < 0.05) with hypohydration than euhydration (995 ± 65 vs. 428 ± 345 mOsmol/kg; 1.027 ± 0.003 vs. 1.016 ± 0.007 g/mL) prior to exercise testing, as was perceived thirst. Swimming performance (p = 0.86) and peak force production (p = 0.72) on the starting block did not differ between the hypohydration and euhydrated condition (63.00 ± 4.26 vs. 63.09 ± 4.52 s; 1322 ± 236 vs. 1315 ± 230 N). The current results indicate that mild hypohydration, which may occur with ad libitum drinking, does not impede peak force production on the starting block and 100 m front crawl performance in university-level competitive swimmers. Planned drinking is not required prior to such an event.

Relationship between thrust, anthropometrics, and dry-land strength in a national junior swimming team

Objectives: This study aimed to (i) assess an anthropometric and thrust inter-limb asymmetry, and; (ii) determine the contribution of anthropometrics, and dry-land upper-body strength and power to the thrust of talented adolescent swimmers. Methods: Eighteen talented adolescent swimmers (12 boys and 6 girls: 15.81 ± 1.62 years old) were evaluated. A set of anthropometric, dry-land upper-body strength and power, and in-water thrust were assessed. Results: Despite the fact that the dominant side presented higher values in anthropometrics (except for the hand surface area) and thrust, non-significant inter-limb differences were found. The symmetry index indicated a symmetry between upper-limbs. Hierarchical linear modeling retained as main predictors of each upper-limb thrust the respective hand surface area (dominant upper limb: estimate = 0.293, 95CI: 0.117; 0.469, p = 0.005; non-dominant upper limb: estimate = 0.295, 95CI: 0.063; 0.526, p = 0.025). The full stroke cycle retained the upper-body dry-land strength as main predictor (estimate = 0.397, 95CI: 0.189; 0.605, p = 0.002). Conclusion: The hand surface area and upper-body strength were the main predictors of each upper-limb and full stroke cycle thrust, respectively. Hence, coaches and practitioners should aim to carefully maximize the hand surface area (by finger spreading) while performing the stroke, as well as dry-land upper-body strength in order to enhance the performance.

5 km front crawl in pool and open water swimming: breath-by-breath energy expenditure and kinematic analysis

PURPOSE

Breath-by-breath energy expenditure during open water swimming has not yet been explored in an ecological environment. This study aimed to investigate and compare energetics and kinematics of 5 km swimming, in both swimming pool and open water conditions.

METHODS

Through four independent studies, oxygen uptake ([Formula: see text]₂) kinetics, heart rate (HR), blood lactate concentration ([La^-]) and glucose level (BGL), metabolic power ([Formula: see text]), energy cost (C) and kinematics were assessed during 5 km front crawl trials in a swimming pool and open water conditions. A total of 38 competitive open water swimmers aged 16-27 years volunteered for this four part investigation: Study A (pool, ten females, 11 males), Study B (pool, four females, six males), Study C (pool case study, one female) and Study D (open water, three females, four males).

RESULTS

In the swimming pool, swimmers started with an above average swimming speed (v), losing efficiency along the 5 km, despite apparent homeostasis for [La^-], BGL, [Formula: see text]₂, [Formula: see text] and C. In open water, swimmers started the 5 km with a below average v, increasing the stroke rate (SR) in the last 1000 m. In open water, [Formula: see text]₂ kinetics parameters, HR, [La^-], BGL, respiratory exchange ratio and C were affected by the v and SR fluctuations along the 5 km.

CONCLUSIONS

Small fluctuations were observed for energetic variables in both conditions, but changes in C were lower in swimming pool than in open water. Coaches should adjust the training plan accordingly to the specificity of open water swimming.

[Formula: see text] kinetics and energy contribution in simulated maximal performance during short and middle distance-trials in swimming

PURPOSE

This study aims to analyze swimmers' oxygen uptake kinetics ([Formula: see text]K) and bioenergetic profiles in 50, 100, and 200 m simulated swimming events and determine which physiological variables relate with performance.

METHODS

Twenty-eight well-trained swimmers completed an incremental test for maximal oxygen uptake (Peak-[Formula: see text]) and maximal aerobic velocity (MAV) assessment. Maximal trials (MT) of 50, 100, and 200-m in front crawl swimming were performed for [Formula: see text]K and bioenergetic profile. [Formula: see text]K parameters were calculated through monoexponential modeling and by a new growth rate method. The recovery phase was used along with the blood lactate concentration for bioenergetics profiling.

RESULTS

Peak-[Formula: see text] (57.47 ± 5.7 ml kg^-1 min^-1 for male and 53.53 ± 4.21 ml kg^-1 min^-1 for female) did not differ from [Formula: see text]_peak attained at the 200-MT for female and at the 100 and 200-MT for male. From the 50-MT to 100-MT and to the 200-MT the [Formula: see text]K presented slower time constants (8.6 ± 2.3 s, 11.5 ± 2.4 s and 16.7 ± 5.5 s, respectively), the aerobic contribution increased (~ 34%, 54% and 71%, respectively) and the anaerobic decreased (~ 66%, 46% and 29%, respectively), presenting a cross-over in the 100-MT. Both energy systems, MAV, Peak-[Formula: see text], and [Formula: see text] peak of the MT's were correlated with swimming performance.

DISCUSSION

The aerobic energy contribution is an important factor for performance in 50, 100, and 200-m, regardless of the time taken to adjust the absolute oxidative response, when considering the effect on a mixed-group regarding sex. [Formula: see text]K speeding could be explained by a faster initial pacing strategy used in the shorter distances, that contributed for a more rapid increase of the oxidative contribution to the energy turnover.

Human thrust in aquatic environment: The effect of post-activation potentiation on flutter kick

Herein, we analyse by experimental techniques the human kicking thrust and measure the effect of a warm-up routine that includes post-activation potentiation (PAP) sets on front-crawl flutter kick thrust, kinematics, and performance. Sixteen male competitive swimmers with 22.13 ± 3.84 years of age were randomly assigned in a crossover manner to undergo a standard warm-up (non-PAP; control condition) and a warm-up that included PAP sets (PAP; experimental condition) consisting in 2 × 5 repetitions of unloaded countermovement jump. Participants performed a 25 m all-out trial in front-crawl with only flutter kicks eight min after each warm-up. Kinetics (i.e., peak thrust, mean thrust, and thrust-time integral) and kinematics (i.e., speed, speed fluctuation and kicking frequency) were experimentally collected by an in-house customized system composed of differential pressure sensors, speedo-meter, and underwater camera. Peak thrust (P = 0.02, d = 0.66) and mean thrust (P = 0.10, d = 0.40) were increased by 15% in PAP compared to non-PAP. Large and significant differences were noted in speed (P = 0.01, d = 0.54) and speed fluctuation (P = 0.02, d = 0.58), which improved by 10% in PAP compared with non-PAP. In conclusion, a warm-up that includes PAP sets improves kicking thrust, kinematics and performance.

The energy cost of swimming and its determinants

The energy expended to transport the body over a given distance (C, the energy cost) increases with speed both on land and in water. At any given speed, C is lower on land (e.g., running or cycling) than in water (e.g., swimming or kayaking) and this difference can be easily understood when one considers that energy should be expended (among the others) to overcome resistive forces since these, at any given speed, are far larger in water (hydrodynamic resistance, drag) than on land (aerodynamic resistance). Another reason for the differences in C between water and land locomotion is the lower capability to exert useful forces in water than on land (e.g., a lower propelling efficiency in the former case). These two parameters (drag and efficiency) not only can explain the differences in C between land and water locomotion but can also explain the differences in C within a given form of locomotion (swimming at the surface, which is the topic of this review): e.g., differences between strokes or between swimmers of different age, sex, and technical level. In this review, the determinants of C (drag and efficiency, as well as energy expenditure in its aerobic and anaerobic components) will, thus, be described and discussed. In aquatic locomotion it is difficult to obtain quantitative measures of drag and efficiency and only a comprehensive (biophysical) approach could allow to understand which estimates are "reasonable" and which are not. Examples of these calculations are also reported and discussed.

Physiological Responses and Swimming Technique During Upper Limb Critical Stroke Rate Training in Competitive Swimmers

The aim of this study was to examine how arm stroke swimming with critical stroke rate (CSR) control would influence physiological responses and stroke variables in an effort to identify a new swimming training method. Seven well-trained male competitive swimmers (19.9 ± 1.4 years of age) performed maximal 200 and 400 m front crawl swims to determine the CSR and critical swimming velocity (CV), respectively. Thereafter, they were instructed to perform tests with 4 × 400 m swimming bouts at the CSR and CV. The swimming time (CSR test: 278.96 ± 2.70 to 280.87 ± 2.57 s, CV test: 276.17 ± 3.36 to 277.06 ± 3.64 s), heart rate, and rated perceived exertion did not differ significantly between tests for all bouts. Blood lactate concentration after the fourth bout was significantly lower in the CSR test than in the CV test (3.16 ± 1.43 vs. 3.77 ± 1.52 mmol/l, p < 0.05). The stroke rate and stroke length remained stable across bouts in the CSR test, whereas the stroke rate increased with decreased stroke length across bouts in the CV test (p < 0.05). There were significant differences in the stroke rate (39.27 ± 1.22 vs. 41.47 ± 1.22 cycles/min, p < 0.05) and stroke length (2.20 ± 0.07 vs. 2.10 ± 0.04 m/stroke, p < 0.05) between the CSR and CV tests in the fourth bout. These results indicate that the CSR could provide the optimal intensity for improving aerobic capacity during arm stroke swimming, and it may also help stabilize stroke technique.

Skillful Swimming in Age-Groups Is Determined by Anthropometrics, Biomechanics and Energetics

The aim was to compare the anthropometrics, biomechanics and energetics in young swimmers of different competitive levels. Seventy-five boys aged between 11 and 13 years-old with a broad range of performances were ranked based on their personal best time in the men’s 100m freestyle event and then split-up into three tiers (Tier-1, i.e., top-tier, best performers; Tier-2, mid-tier; Tier-3, lower-tier). A set of anthropometric features was measured (height, body mass, arm span and trunk transverse surface area). Stroke kinematics (speed, stroke length, stroke frequency) was assessed by a Speedo-meter. Swim efficiency was then estimated (stroke index, speed fluctuation, Froude efficiency). Hydrodynamics assessment encompassed the estimation of active drag and drag coefficient by velocity perturbation method and a set of dimensionless numbers (Froude, hull speed, Reynolds). Mechanical power (to overcome drag, transfer of kinetic energy to water, external power) and power input were derived. There was a significant variation with moderate effect sizes in all anthropometric features but the trunk transverse surface area. Tier-1 swimmers were taller, heavier and with longer limbs than remaining counterparts. There were also significant variations in the stroke kinematics with moderate-large effect sizes. Tier-1 swimmers showed higher stroke frequency, stroke length, speed, stroke index and propelling efficiency but lower speed fluctuations. Reynold number, Froude number and hull speed were significantly higher in Tier-1 swimmers, denoting large effect sizes. The mechanical power and power input delivered were significantly higher in tier-1 swimmers, showing moderate effect sizes. As a conclusion, it was noted significant variations, with moderate-large effect sizes, among the three tiers, for the vast majority of the selected variables. The better performances by tier-1 swimmers were related to their anthropometrics, biomechanics and energetics.

VO₂FITTING: A Free and Open-Source Software for Modelling Oxygen Uptake Kinetics in Swimming and other Exercise Modalities

The assessment of oxygen uptake (VO₂) kinetics is a valuable non-invasive way to evaluate cardiorespiratory and metabolic response to exercise. The aim of the study was to develop, describe and evaluate an online VO₂ fitting tool (VO₂FITTING) for dynamically editing, processing, filtering and modelling VO₂ responses to exercise. VO₂FITTING was developed in Shiny, a web application framework for R language. Validation VO₂ datasets with both noisy and non-noisy data were developed and applied to widely-used models (n = 7) for describing different intensity transitions to verify concurrent validity. Subsequently, we then conducted an experiment with age-group swimmers as an example, illustrating how VO₂FITTING can be used to model VO₂ kinetics. Perfect fits were observed, and parameter estimates perfectly matched the known inputted values for all available models (standard error = 0; p < 0.001). The VO₂FITTING is a valid, free and open-source software for characterizing VO₂ kinetics in exercise, which was developed to help the research and performance analysis communities.

The Impact of Resistance Training on Swimming Performance: A Systematic Review

BACKGROUND

The majority of propulsive forces in swimming are produced from the upper body, with strong correlations between upper body strength and sprint performance. There are significant gaps in the literature relating to the impact of resistance training on swimming performance, specifically the transfer to swimming performance.

OBJECTIVE

The aims of this systematic literature review are to (1) explore the transfer of resistance-training modalities to swimming performance, and (2) examine the effects of resistance training on technical aspects of swimming.

METHODS

Four online databases were searched with the following inclusion criteria: (1) journal articles with outcome measures related to swimming performance, and (2) competitive swimmers participating in a structured resistance-training programme. Exclusion criteria were (1) participants with a mean age <16 years; (2) untrained, novice, masters and paraplegic swimmers; (3) triathletes and waterpolo players; (4) swimmers with injuries or illness; and (5) studies of starts and turns specifically. Data were extracted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the Physiotherapy Evidence Database (PEDro) scale was applied.

RESULTS

For optimal transfer, specific, low-volume, high-velocity/force resistance-training programmes are optimal. Stroke length is best achieved through resistance training with low repetitions at a high velocity/force. Resisted swims are the most appropriate training modality for improving stroke rate.

CONCLUSION

Future research is needed with respect to the effects of long-term resistance-training interventions on both technical parameters of swimming and overall swimming performance. The results of such work will be highly informative for the scientific community, coaches and athletes.

Improvement of Flutter-Kick Performance in Novice Surface Combat Swimmers With Increased Hip Strength

PURPOSE

To examine strength, range of motion, anthropometric, and physiological contributions to novice surface-combat-swimming (sCS) performance and establish differences from freestyle-swimming (FS) performance to further understand the transition of FS to sCS performance.

METHODS

A total of 13 competitive swimmers (7 male and 6 female; 27.7 [2.3] y; 176.2 [2.6] cm; 75.4 [3.9] kg) completed 8 testing sessions consisting of the following: physiological land-based measurements for maximal anaerobic and aerobic capacity and upper- and lower-extremity strength and range of motion, an sCS anaerobic capacity swim test measuring peak and mean force and fatigue index, 2 aerobic capacity tests measuring maximal aerobic capacity for both FS and sCS, and four 500-m performance swims for time, 1 FS, and 3 sCS. Separate multiple linear-regression analysis was used to analyze predictors of both sCS and FS performance models.

RESULTS

FS performance was predicted by the final FS maximal oxygen uptake with an R2 of 42.03% (F1,10 = 7.25; P = .0226), whereas sCS performance was predicted by isometric hip-extension peak strength with an R2 of 41.46% (F1,11 = 7.79; P = .0176).

CONCLUSIONS

Results demonstrate that different physiological characteristics predict performance, suggesting that an altered strategy is used for novice sCS than FS. It is suggested that this may be due to the added constraints as mandated by mission requirements including boots, weighted gear, and clandestine requirements with hips lowered beneath the surface. Further research should examine the kinematics of the sCS flutter kick to improve performance by developing training strategies specific for the task.

Effect of leg kick on active drag in front-crawl swimming: Comparison of whole stroke and arms-only stroke during front-crawl and the streamlined position

The purpose of this study was to examine the effect of leg kick on the resistance force in front-crawl swimming. The active drag in front-crawl swimming with and without leg motion was evaluated using measured values of residual thrust (MRT method) and compared with the passive drag of the streamlined position (SP) for the same swimmers. Seven male competitive swimmers participated in this study, and the testing was conducted in a swimming flume. Each swimmer performed front-crawl under two conditions: using arms and legs (whole stroke: WS) and using arms only (arms-only stroke: AS). Active drag and passive drag were measured at swimming velocities of 1.1 and 1.3 m s^-1 using load cells connected to the swimmer via wires. We calculated a drag coefficient to compare the resistances of the WS, AS and SP at each velocity. For both the WS and AS at both swimming velocities, active drag coefficient was found to be about 1.6-1.9 times larger than that in passive conditions. In contrast, although leg movement did not cause a difference in drag coefficient for front-crawl swimming, there was a large effect size (d = 1.43) at 1.3 m s^-1. Therefore, although upper and lower limb movements increase resistance compared to the passive condition, the effect of leg kick on drag may depend on swimming velocity.

Underwater near-infrared spectroscopy can measure training adaptations in adolescent swimmers

The development of an underwater near-infrared spectroscopy (uNIRS) device has enabled previously unattainable measurements of peripheral muscle hemodynamics and oxygenation to be taken within the natural aquatic environment. The purposes of this study were (i) to trial the use of uNIRS, in a real world training study, and (ii) to monitor the effects of a swim training program upon muscle oxygenation status in short distance swimming. A total of 14 junior club level swimmers completed a repeated swim sprint test before and after an eight week endurance training program. A waterproof, portable Near-Infrared Spectroscopy device was attached to the vastus lateralis. uNIRS successfully measured changes in muscle oxygenation and blood volume in all individuals; rapid sub-second time resolution of the device was able to demonstrate muscle oxygenation changes during the characteristic swim movements. Post training heart rate recovery and swim performance time were significantly improved. uNIRS data also showed significant changes. A larger rise in deoxyhemoglobin during individual sprints suggested training induced an increase in muscle oxygen extraction; a faster recovery time for muscle oxygenation suggested positive training induced changes and significant changes in muscle blood flow also occur. As a strong correlation was seen between an increased reoxygenation rate and an improved swim performance time, these findings support the use of uNIRS as a new performance analysis tool in swimming.

Warm-up for Sprint Swimming: Race-Pace or Aerobic Stimulation? A Randomized Study

Neiva, HP, Marques, MC, Barbosa, TM, Izquierdo, M, Viana, JL, Teixeira, AM, and Marinho, DA. Warm-up for sprint swimming: race-pace or aerobic stimulation? A randomized study. J Strength Cond Res 31(9): 2423-2431, 2017-The aim of this study was to compare the effects of 2 different warm-up intensities on 100-m swimming performance in a randomized controlled trial. Thirteen competitive swimmers performed two 100-m freestyle time-trials on separate days after either control or experimental warm-up in a randomized design. The control warm-up included a typical race-pace set (4 × 25 m), whereas the experimental warm-up included an aerobic set (8 × 50 m at 98-102% of critical velocity). Cortisol, testosterone, blood lactate ([La]), oxygen uptake (V[Combining Dot Above]O2), heart rate, core (Tcore and Tcorenet) and tympanic temperatures, and rating of perceived exertion (RPE) were monitored. Stroke length (SL), stroke frequency (SF), stroke index (SI), and propelling efficiency (ηp) were assessed for each 50-m lap. We found that V[Combining Dot Above]O2, heart rate, and Tcorenet were higher after experimental warm-up (d > 0.73), but only the positive effect for Tcorenet was maintained until the trial. Performance was not different between conditions (d = 0.07). Experimental warm-up was found to slow SF (mean change ±90% CL = 2.06 ± 1.48%) and increase SL (1.65 ± 1.40%) and ηp (1.87 ± 1.33%) in the first lap. After the time-trials, this warm-up had a positive effect on Tcorenet (d = 0.69) and a negative effect on [La] (d = 0.56). Although the warm-ups had similar outcomes in the 100-m freestyle, performance was achieved through different biomechanical strategies. Stroke length and efficiency were higher in the first lap after the experimental warm-up, whereas SF was higher after control warm-up. Physiological adaptations were observed mainly through an increased Tcore after experimental warm-up. In this condition, the lower [La] after the trial suggests lower dependency on anaerobic metabolism.

Physiological demands of a swimming-based video game: Influence of gender, swimming background, and exergame experience

Active video games (exergames) may provide short-term increase in energy expenditure. We explored the effects of gender and prior experience on aerobic and anaerobic energy systems contributions, and the activity profiles of 40 participants playing with a swimming exergame. We recorded oxygen consumption and assessed blood lactate after each swimming technique. We also filmed participants’ gameplays, divided them into different phases and tagged them as active or inactive. Anaerobic pathway accounted for 8.9 ± 5.6% of total energy expenditure and although experienced players were less active compared to novice counterparts (η² < 0.15, p < 0.05), physiological measures were not different between performing groups. However, players with real-swimming experience during the first technique had higher heart rate (partial-η² = 0.09, p < 0.05). Our results suggest that short-term increase in physiological measures might happen in the beginning of gameplay because of unfamiliarity with the game mechanics. Despite low levels of activity compared to real sport, both aerobic and anaerobic energy systems should be considered in the evaluation of exergames. Game mechanics (involving the whole body) and strategies to minimize pragmatic play might be used for effective and meaningful game experience.

Biomechanics, energetics and coordination during extreme swimming intensity: effect of performance level

The present study aimed to examine how high- and low-speed swimmers organise biomechanical, energetic and coordinative factors throughout extreme intensity swim. Sixteen swimmers (eight high- and eight low-speed) performed, in free condition, 100-m front crawl at maximal intensity and 25, 50 and 75-m bouts (at same pace as the previous 100-m), and 100-m maximal front crawl on the measuring active drag system (MAD-system). A 3D dual-media optoelectronic system was used to assess speed, stroke frequency, stroke length, propelling efficiency and index of coordination (IdC), with power assessed by MAD-system and energy cost by quantifying oxygen consumption plus blood lactate. Both groups presented a similar profile in speed, power output, stroke frequency, stroke length, propelling efficiency and energy cost along the effort, while a distinct coordination profile was observed (F_{(3, 42)} = 3.59, P = 0.04). Speed, power, stroke frequency and propelling efficiency (not significant, only a tendency) were higher in high-speed swimmers, while stroke length and energy cost were similar between groups. Performing at extreme intensity led better level swimmers to achieve superior speed due to higher power and propelling efficiency, with consequent ability to swim at higher stroke frequencies. This imposes specific constraints, resulting in a distinct IdC magnitude and profile between groups.

The Effects of Different Warm-up Volumes on the 100-m Swimming Performance: A Randomized Crossover Study

The aim of this study was to compare the effect of 3 different warm-up (WU) volumes on 100-m swimming performance. Eleven male swimmers at the national level completed 3 time trials of 100-m freestyle on separate days and after a standard WU, a short WU (SWU), or a long WU (LWU) in a randomized sequence. All of them replicated some usual sets and drills, and the WU totaled 1,200 m, the SWU totaled 600 m, and the LWU totaled 1,800 m. The swimmers were faster after the WU (59.29 seconds; confidence interval [CI] 95%, 57.98-60.61) and after the SWU (59.38 seconds; CI 95%, 57.92-60.84) compared with the LWU (60.18 seconds; CI 95%, 58.53-61.83). The second 50-m lap after the WU was performed with a higher stroke length (effect size [ES] = 0.77), stroke index (ES = 1.26), and propelling efficiency (ES = 0.78) than that after the SWU. Both WU and SWU resulted in higher pretrial values of blood lactate concentrations [La] compared with LWU (ES = 1.58 and 0.74, respectively), and the testosterone:cortisol levels were increased in WU compared with LWU (ES = 0.86). In addition, the trial after WU caused higher [La] (ES ≥ 0.68) and testosterone:cortisol values compared with the LWU (ES = 0.93). These results suggest that an LWU could impair 100-m freestyle performance. The swimmers showed higher efficiency during the race after a 1200-m WU, suggesting a favorable situation. It highlighted the importance of the [La] and hormonal responses to each particular WU, possibly influencing performance and biomechanical responses during a 100-m race.

Velocity, aerobic power and metabolic cost of whole body and arms only front crawl swimming at various stroke rates

PURPOSE

Stroke rate (SR) has not been considered in previous research examining the relative roles of the limbs in front-crawl performance. This study compared velocity, aerobic power ([Formula: see text]) and metabolic cost (C) between whole body (WB) and arms only (AO) front-crawl swimming across various intensities while controlling SR.

METHODS

Twenty Australian national swimmers performed six 200 m front-crawl efforts under two conditions: (1) WB swimming and, (2) AO swimming. Participants completed the 200 m trials under three SR conditions: "low" (22-26 stroke-cycles min(-1)), "moderate" (30-34 stroke-cycles min(-1) and "high" (38-42 stroke-cycles min(-1)). [Formula: see text] was continuously measured, with C, velocity, SR, and kick rate calculated for each effort.

RESULTS

Regardless of the SR condition and sex, AO velocity was consistently lower than WB velocity by ~11.0 % (p < 0.01). AO [Formula: see text] was lower than WB [Formula: see text] at all SR conditions for females (p < 0.01) and at the "high" SR for males (p < 0.01). C did not differ between WB and AO at any SR for both sexes (p > 0.01). When C was expressed as a function of velocity, WB and AO regression equations differed for males (p = 0.01) but not for females (p = 0.087). Kick rate increased as SR increased (p < 0.01), though the kick-to-stroke rate ratio remained constant.

CONCLUSION

Elite swimmers gain ~11 % in velocity from their kick and, when used in conjunction with the arm stroke at the swimmers' preferred frequency, the metabolic cost of WB and AO swimming is the same. Coaches should consider these results when prescribing AO sets if their intention is to reduce the metabolic load.