Hypoxia matters: comparison of external and internal training load markers during an 8-week resistance training program in normoxia, normobaric hypoxia and hypobaric hypoxia.

PURPOSE: To compare external and internal training load markers during resistance training (RT) in normoxia (N), intermittent hypobaric hypoxia (HH), and intermittent normobaric hypoxia (NH). METHODS: Thirty-three volunteers were assigned an 8-week RT program in either N (690 m, n = 10), HH (2320 m, n = 10), or NH (inspired fraction of oxygen = 15.9%; ~ 2320 m, n = 13). The RT program (3x/week) consisted of six exercises, with three sets of six to 12 repetitions at ~ 70% of one repetition maximum (1RM) with the first session of each week used for analysis. 1RM in back squat and bench press was used to evaluate muscle strength before and after the program. External load was assessed by the volume load relative to body mass (RVL, kg·kg-1). Internal load was assessed by the ratings of perceived exertion (RPE) and heart rate (HR). RESULTS: Smaller relative improvements were found for the back squat in the N group (11.5 ± 8.8%) when compared to the NH group (22.2 ± 8.2%, P = 0.01) and the HH group (22 ± 8.1%, P = 0.02). All groups showed similar RVL, HR responses and RPE across the program (P˃0.05). However, reduced HR recovery values, calculated as the difference between the highest HR value (HRpeak) and the resting heart rate after a two min rest, were seen in the N and NH groups across the program (P < 0.05). CONCLUSION: It seems that 8 weeks of intermittent RT in hypoxic environments could maximize time-efficiency when aiming to improve strength levels in back squat without evoking higher levels of physiological stress. Performing RT at hypobaric hypoxia may improve the cardiorespiratory response, which in turn could speed recovery.

Adherence to the physical activity guideline beyond the recommended minimum weekly amount: impacts on indicators of physical function in older adults.

Introduction: The extent to which additional health benefits of accumulating twice the minimum amount of time in moderate-to-vigorous physical activity (MVPA) affects indicators of physical function in older adults is unclear. Therefore, the aim of the present study was to assess indicators of physical function in older adults who accumulate at least 150 but less than 300 min/week of MVPA compared to those accumulating at least 300 min/week. Methods: Indicators of physical function, including handgrip strength, 5 times sit-to-stand test (5-STS), squat jump and 6-min walk test (6MWT) were assessed in a sample of 193 older men (n = 71, 67 ± 2 years), and women (n = 122, 67 ± 2 years), who all accumulated at least 150 weekly minutes of MVPA. Time in MVPA was assessed by accelerometry during 1 week and engagement in muscle strengthening activities (MSA) was assessed by self-report. Protein intake was assessed by a food-frequency-questionnaire. Participants were classified as physically active (≥150 but <300 min of MVPA per week) or as highly physically active (≥300 min of MVPA per week). Results: Factorial analysis of variance revealed that older adults accumulating at least 300 min of MVPA per week had a significantly (p < 0.05) better 6MWT performance and overall physical function compared to the less active group. These findings remained significant after further adjustment for MSA, sex, waist circumference and protein intake. In contrast, no significant differences in indicators of muscle strength were observed between the two groups. Discussion: Adherence to twice the recommended minimum amount of weekly MVPA time is related to a better physical function, evidenced by a better walking performance compared to adherence to the minimum weekly amount of MVPA. This finding emphasizes the benefits of accumulating daily MVPA beyond the minimum recommended amount to optimize the ability to perform activities of daily living, thus reducing the burden of physical disability and related health-care costs.

Acute Exposure to Normobaric Hypoxia Impairs Balance Performance in Sub-elite but Not Elite Basketball Players.

Although high and simulated altitude training has become an increasingly popular training method, no study has investigated the influence of acute hypoxic exposure on balance in team-sport athletes. Therefore, the purpose of this study was to investigate whether acute exposure to normobaric hypoxia is detrimental to balance performance in highly-trained basketball players. Nine elite and nine sub-elite male basketball players participated in a randomized, single-blinded, cross-over study. Subjects performed repeated trials of a single-leg balance test (SLBT) in an altitude chamber in normoxia (NOR; approximately sea level) with FiO2 20.9% and PiO2 ranging from 146.7 to 150.4 mmHg and in normobaric hypoxia (HYP; ~3,800 m above sea level) with FiO2 13.0% and PiO2 ranging from 90.9 to 94.6 mmHg. The SLBT was performed three times: 15 min after entering the environmental chamber in NOR or HYP, then two times more interspersed by 3-min rest. Peripheral oxygen saturation (SpO2) and heart rate (HR) were recorded at four time points: after the initial 15-min rest inside the chamber and immediately after each SLBT. Across the cohort, the balance performance was 7.1% better during NOR than HYP (P < 0.01, η p 2 = 0.58). However, the performance of the elite group was not impaired by HYP, whereas the sub-elite group performed worse in the HYP condition on both legs (DL: P = 0.02, d = 1.23; NDL: P = 0.01, d = 1.43). SpO2 was lower in HYP than NOR (P < 0.001, η p 2 = 0.99) with a significant decline over time during HYP. HR was higher in HYP than NOR (P = 0.04, η p 2 = 0.25) with a significant increase over time. Acute exposure to normobaric hypoxia detrimentally affected the balance performance in sub-elite but not elite basketball players.

Hook Breathing Facilitates SaO2 Recovery After Deep Dives in Freedivers With Slow Recovery.

To facilitate recovery from hypoxia, many freedivers use a breathing method called "hook breathing" (HB) after diving, involving an interrupted exhale to build up intrapulmonary pressure. Some divers experience a delay in recovery of arterial oxygen saturation (SaO2) after diving, interpreted as symptoms of mild pulmonary edema, and facilitated recovery may be especially important in this group to avoid hypoxic "blackout." We examined the influence of HB on recovery of SaO2 in freedivers with slow recovery (SR) and fast recovery (FR) of SaO2 after deep "free immersion" (FIM) apnea dives to 30 m depth. Twenty-two male freedivers, with a mean (SD) personal best in the discipline FIM of 57(26) m, performed two 30 m deep dives, one followed by HB and one using normal breathing (NB) during recovery, at different days and weighted order. SaO2 and heart rate (HR) were measured via pulse oximetry during recovery. The SR group (n = 5) had a faster SaO2 recovery using HB, while the FR group (n = 17) showed no difference between breathing techniques. At 105 s, the SR group reached a mean (SD) SaO2 of 95(5)% using HB, while using NB, their SaO2 was 87(5)% (p < 0.05), and 105-120 s after surfacing SaO2 was higher with HB (p < 0.05). In SR subjects, the average time needed to reach 95% SaO2 with HB was 60 s, while it was 120 s at NB (p < 0.05). HR was similar in the SR group, while it was initially elevated at HB in the FR group (p < 0.05). We conclude that HB efficiently increases SaO2 recovery in SR individuals, but not in the FR group. The proposed mechanism is that increased pulmonary pressure with HB will reverse any pulmonary edema and facilitate oxygen uptake in divers with delayed recovery.

Physiological demands of standing and wheelchair fencing in able-bodied fencers.

BACKGROUND: The purpose of this study was to determine the cardiorespiratory demands of standing and wheelchair (seated) fencing in a group of able-bodied fencers during simulated competitive bouts. METHODS: Participants were ten male able-bodied fencers of regional level with previous training experience in wheelchair fencing. After a standardized warm-up, participants performed two series of simulated competitive épée bouts (5 and 15 touches) in a random order, either while standing or while sitting in a wheelchair. Expired gas was analyzed for oxygen consumption (V̇O2) and respiratory exchange ratio (RER) and heart rate were continually monitored. Energy expenditure (EE) was subsequently calculated. RESULTS: V̇O2, HR and EE peak responses were greater during standing than seated fencing (P<0.05). Mean V̇O2 during all ST bouts (5- and 15-touch) was 43% greater than in wheelchair fencing (44.2±7.8 vs. 25.1±5.4 mL/kg/min). Mean HR during the standing 5- and 15-touch bouts was 91±20% and 84±7%, respectively, of that recorded during the seated bouts. HR, V̇O2 and EE data also indicated that the 15-touch bouts were more physiologically demanding than the 5-touch bouts (P<0.01). The HR-V̇O2 relationship was similar between both fencing modes. The duration of the 5- and 15-touch bouts were shorter for the seated than the standing bouts (P<0.01). CONCLUSIONS: The physiological demands of wheelchair fencing are lower than those for standing fencing. Furthermore, the physiology of 5 versus 15-touch bouts, similar to those undertaken in fencing competition, also differs.

Heart-Rate Variability in Elite Synchronized Swimmers.

PURPOSE: To determine whether heart-rate variability (HRV) was correlated with other training-load and training-tolerance markers for monitoring the effect of a training session on elite synchronized swimmers. METHODS: The authors recorded the resting HRV of 12 elite swimmers (mean age = 21.5 [3.5] y) 3 times over 1 wk with a cadence of 48 h prior to the 2015 World Swimming Championships. They continuously monitored heart rate and obtained salivary cortisol (SC) samples before and after the last training session of the week. The authors measured capillary blood lactate (La) 2, 4, and 8 min after the last training session and monitored recovery HRV. They assessed rating of perceived exertion (RPE) over the entire session and tested the association between the highest La concentration (Lapeak), SC, and RPE and relative changes (Δ%) in the natural logarithm of the root-mean-square successive difference of intervals (LnRMSSD). The authors also calculated the smallest worthwhile change of the averaged pre and post LnRMSSD measurements. RESULTS: There were periods of pronounced bradycardia (60.5 [16.7] beats/min) during training exercises corresponding to apneic exercise. The magnitude-based inferences showed nonclinically meaningful changes of LnRMSSD. Lapeak (6.8 [2.7] mmol/L) correlated positively with Δ%LnRMSSD and Δ%SC (r = .89, P = .001 and r = .61, P = .04, respectively). CONCLUSIONS: There was no change in LnRMSSD and Lapeak, Δ%SC, and RPE indicated reduced sympathetic activation and positive adaptation to the stress imposed by the session. Isolated HRV assessment may reveal a controversial interpretation of autonomic nervous system status or the training tolerance in elite synchronized swimming athletes due to the influence of the diving response.

Mean Propulsive Velocity Is a Viable Method for Adjusting the Resistance-Training Load at Moderate Altitude.

We examined the viability of using mean propulsive velocity (MPV) to adjust the load in the countermovement jump (CMJ) at moderate altitude. Twenty-four volunteers were assigned to a 4-week power-oriented resistance training (RT) program in either normoxia (N, 690 m) or intermittent hypobaric hypoxia (IH, 2,320 m). The load was adjusted to maintain execution velocity of CMJ at 1m·s-1 of MPV. Relative peak power output (Prel), and percentage of velocity loss throughout the sets (VL) were determined for each session. The internal load was measured by the rating of perceived exertion (RPE). The absolute load lifted was higher in IH compared to N (75.6 ± 8.4 vs. 58.5 ± 12.3 kg P < 0.001). However, similar relative increases for both groups were found when comparing the final values (IH: 8.2%, P = 0.007; N: 9.8%, P = 0.03) with no changes in VL between groups (P = 0.36). Post-study Prel improved significantly only in IH (+7% W·kg-1, P = 0.002). Mean RPE was greater in IH vs. N (6.8 ± 1.5 vs. 5.6 ± 2, P < 0.001). The MPV seems to be a viable method for adjusting external load during RT at moderate altitude. However, given that RT at moderate altitude increases RPE, it is prudent to monitor internal load when using the MPV to best determine the actual physiological stress of the session.

Blood lactate accumulation during competitive freediving and synchronized swimming.

A number of competitive water sports are performed while breath-holding (apnea). Such performances put large demands on the anaerobic system, but the study of lactate accumulation in apneic sports is limited. We therefore aimed to determine and compare the net lactate accumulation (NLA) during competition events in six disciplines of competitive freediving (FD) and three disciplines of synchronized swimming (SSW). The FD disciplines were: static apnea (STA; n = 14); dynamic apnea (DYN; n = 19); dynamic apnea no fins (DNF; n = 16); constant weight (CWT; n = 12); constant weight no fins (CNF; n = 8); free immersion (FIM; n =10). The SSW disciplines were solo (n = 21), duet (n = 31) and team (n = 34). Capillary blood lactate concentration was measured before and three minutes after competition performances, and apneic duration and performance variables were recorded. In all nine disciplines NLA was observed. The highest mean (SD) NLA (mmol·L-1) was found in CNF at 6.3 (2.2), followed by CWT at 5.9 (2.3) and SSW solo at 5 (1.9). STA showed the lowest NLA 0.7 (0.7) mmol·L-1 compared to all other disciplines (P ⟨ 0.001). The NLA recorded shows that sports involving apnea involve high levels of anaerobic activity. The highest NLA was related to both work done by large muscle groups and long apneic periods, suggesting that NLA is influenced by both the type of work and apnea duration, with lower NLA in SSW due to shorter apneic episodes with intermittent breathing.

Bioelectrical impedance vector analysis (BIVA) for measuring the hydration status in young elite synchronized swimmers.

PURPOSE: The assessment of body hydration is a complex process, and no measurement is valid for all situations. Bioelectrical impedance vector analysis (BIVA) has emerged as a relatively novel technique for assessing hydration status in sports. We applied BIVA a) to determine hydration changes evoked by an intense synchronized swimming (SS) training session; b) to characterize the sample of young elite swimmers in relation with a nonathletic reference population; and c) to generate its 50%, 75% and 95% percentiles of the bioelectrical variables. METHODS: Forty-nine elite SS female swimmers of two age categories, comen (Co: 13.9 ± 0.9 years, n = 34) and junior (Jr: 16.3 ± 0.6 years, n = 15), performed a long, high intensity training session. Body mass (BM) and bioelectrical variables (R, resistance; Xc, reactance; PA, phase angle; and Z, impedance module) were assessed pre- and post-training. BIVA was used to characterize 1) the distribution pattern of the bioelectrical vector (BIA vector) for both age groups, and 2) pre- to post-training BIA vector migration. Bioelectrical variables were also correlated with BM change values. RESULTS: Most swimmers were mostly located outside the 75% and some beyond the 95% percentile of the bioelectrical tolerance ellipses of the general population. The BIA vector showed statistically significant differences in both Co (T2 = 134.7, p = 0.0001) and Jr (T2 = 126.2, p < 0.001). Both groups were also bioelectrically different (T2 = 17.6, p < 0.001). After the training session, a decrease in BM (p = 0.0001) and an increase in BIA variables (p = 0.01) was observed. BIVA also showed a significant pre-post vector migration both in Co (T2 = 82.1; p < 0.001) and Jr (T2 = 41.8; p < 0.001). No correlations were observed between BM changes and bioelectrical variables. CONCLUSIONS: BIVA showed specific bioelectrical characteristics in young elite SS athletes. Considering the decrease in BM and the migration of the BIA vector, we conclude that the homeostatic hydration status of these young elite female swimmers was affected by the execution of intense training sessions. From a methodological perspective, BIVA appears to be sensitive enough to detect subtle hydration changes, but further research is needed to ensure its validity and reliability. Moreover, these findings highlight the importance of ensuring adequate fluid intake during training in young SS athletes.

Diversificación de patrones en rutinas de solo en natación sincronizada de alto nivel / Patterns of solo routines in high-performance synchronized swimming

El objetivo del presente estudio es determinar y caracterizar la existencia de diferencias estructurales y T-Patterns en la disposición corporal entre las rutinas de solo técnico y libre en la natación sincronizada de alto nivel. Se utilizó un diseño observacional puntual, nomotético y multidimensional. El instrumento de registro fue el programa LINCE v. 1.1. La fiabilidad en la observación se determinó mediante el grado de concordancia intra e interobservador con valores de 0,9 en el índice Kappa. Se analizaron 15 nadadoras finalistas del campeonato del Mundo y 11 del campeonato de España), en 19 rutinas de solo técnico) y 23 de solo libre). Se realizó un análisis descriptivo e inferencial de los registros, así como una detección de T-Patterns, mediante Theme 6 Edu. Se detectó un mayor número de T-Patterns en el solo técnico que en el solo libre. El 69,3 fi (±5,7) del tiempo total de rutina, las nadadoras están en fase de apnea, siendo mayores estos porcentajes en la rutina técnica que en la libre (p <0,05). Se encontraron diferencias significativas entre los tipos de rutina en el análisis de la posición corporal y los niveles de inmersión. En conclusión, podemos afirmar que existen diferencias significativas entre las rutinas de solo libre y solo técnico tanto en la estructura temporal como en los T-Patterns detectados. Los programas técnicos se caracterizan por mayores porcentajes temporales en fases de apnea, elementos en baja inmersión y ejecuciones en posición inferior, así como en la cantidad de T-Patterns detectados (AU)

The aim of the present study is to identify and characterize the structural diHerences and T-Patterns of body posture in technical and free solo routines of high-performance synchronized swimming. 6e study is observational, punctual, nomotetic and multidimensional. Data were registered using LINCE v.1.1. with a fiability intra- and inter-observer of 90fi (Kappa index). The participants were 26 female swimmers (15 finalists in the World Championship 2011 and 11 finalists from the Spanish Championship) and the sample are 19 routines of technical solo and 23 routines of free solo. A descriptive and an inferential analysis were performed, as well as a pattern analysis according to THEME 6 Edu. More T-patterns were detected in the technical solo routines than in the free solo. Results show that in 69,3fi (± 5,7) of the routine’s time, swimmers are in apnea, and this percentage is higher in technical routines than in free routines (p <0,05). Significant diHerences were also found in the body posture and levels of immersion between the two types of routines considered. In conclusion, results suggest that free solo and technical solo routines present significant diHerences in regard to the temporal structure and in the sequential patterns detected. 6e technical routines are characterized by longer apnea episodes, more elements in low immersion and more performances in inferior positions, and more T-patterns (AU)

O objetivo do presente estudo foi caracterizar e determina a existência de diferenças estruturais e de T-Patterns na disposição corporal entre os esquemas técnicos e livres de natação sincronizada de alto nível. Foi utilizado um desenho observacional do tipo: pontual, nomotético e multidimensional. O instrumento de registo utilizado foi o programa LINCE v.1.1. A fiabilidade da observação foi determinadas pelo grau de concordância intra e inter observador com valores de 0,9 no índice Kappa. Foram analisadas 15 nadadoras finalistas do campeonato do Mundo e 11 do campeonato de Espanha, em 19 rotinas de técnicas individuais e 23 individuais livres. Realizou-se uma análise descritiva e inferência dos registos, assim como uma de padrões, mediante o 6eme6 Edu. Foi detetado um maior número de T-Patterns nos esquemas individuais técnicos que nos esquemas livres. Em 69,3fi (±5,7) do tempo total da rotina, as nadadoras estavam em fase de apneia, sendo maiores estas percentagens nas rotinas técnicas que nas livres (p <0,05). Foram encontradas diferenças significativas entre os tipos de rotina na análise da posição corporal e nos níveis de imersão. Em conclusão, podemos afirmar que existem diferenças significativas entre os esquemas livres e os esquemas técnicos tanto na estrutura temporal como nos padrões sequenciais detetados. Os programas técnicos caracterizam-se por maiores percentagens temporais em fases de apneia, elementos em baixa imersão e execuções em posição inferior, assim como na quantidade de T- -Patterns detetados (AU)

Análisis multidimensional de la estructura de las rutinas competitivas en natación sincronizada / Análise multidimensional da estrutura das rotinas competitivas na natação sincronizada / Multidimensional analysis of the structure of competitive routines in synchronized swimming

El objetivo de este estudio fue caracterizar la estructura de las rutinas de solo y dúo de natación sincronizada. Para ello se utilizó un diseño observacional puntual, nomotético y multidimensional. El instrumento observacional ad hoc fue validado por 12 especialistas. Se utilizó como instrumento de registro el programa LINCE. La fiabilidad en la observación se determinó mediante el grado de concordancia intra e interobservador. Dieciocho nadadoras (seis medallistas olímpicas) participaron en el estudio. Se analizaron 39 rutinas: solo técnico (n = 9), solo libre (n = 11), dúo técnico (n = 10) y dúo libre (n = 9). El 61.6 ± 6.4 %) del tiempo de competición las nadadoras estaban con la cara dentro del agua, con apneas máximas de 21.1 ± 4.0 s. La posición más utilizada en el conjunto de rutinas fue la inferior (43.2 ± 5.3 %), siendo la fase de inmersión alta inferior la más reproducida (35.3 ± 5.0 %). En conclusión: 1) se dispone de una herramienta válida para el análisis de la estructura de las rutinas en natación sincronizada, 2) existen diferencias significativas en la estructura de las rutinas atendiendo a la duración total, las fases relativas de apnea y a la inmersión en distintas posiciones corporales

The aim of this study was to characterize the structure of solo and duet-based synchronized swimming routines. This was done using a specific nomothetic multidimensional observational design. The ad hoc observational instrument was validated by 12 specialists. The data was recorded using LINCE software, and observational reliability was determined by calculating the degree of intra-observer and inter-observer agreement. The participants were 18 female swimmers (including six Olympic medallists), and 39 routines were analysed: technical solos (n = 9), free solos (n = 11), technical duets (n = 10) and free duets (n = 9). The swimmers spent 61.6 ± 6.4 % of the competition time with their faces immersed in the water, with maximum apnea of 21.1 ± 4.0 s. The inverted-vertical position was the most widely taken in routines (43.2 ± 5.3 %), with the phase of deep immersion in that position being the most commonly reproduced (35.3 ± 5.0 %). In conclusion: 1) the observational instrument is a valid tool for analysing the structure of routines in synchronized swimming; and 2) there are significant differences in the structure of routines as regards their total duration, episodes of apnea, and the degree of immersion in different body positions

Natação sincronizada, Metodologia observacional, Apneia, Posição corporal, Imersão. RESUMO: O objectivo deste estudo foi caracterizar a estrutura das rotinas individuais e duplas de natação sincronizada. Para tal foi utilizado um delineamento observacional pontual, nomotético e multidimensional. O instrumento observacional ad hoc foi validado por 12 especialistas. Utilizou-se como instrumento de registo o programa LINCE. A fidelidade na observação foi determinada mediante o grau de concordância intra e interobservador. Dezoito nadadoras (seis medalhistas olímpicas) participaram no estudo. Foram analisadas 39 rotinas; solo técnico (n = 9), solo livre (n = 11), duo técnico (n = 10) e duo livre (n = 9). As nadadoras estavam totalmente imersas na água em 61.6 % (± 6.4 %) do tempo de competição, com apneias máximas de 21.1 ± 4.0 s. A posição mais utilizada no conjunto de rotinas foi a imersão inferior (43.2 ± 5.3 %), sendo a fase de imersão total a mais reproduzida (35.3 ± 5.0 %). Em suma: 1) dispõem-se de uma ferramenta válida para a análise da estructura das rotinas na natação sincronizada, 2) existem diferenças significativas na estructura das rotinas atendendo à duração total, às fases relativas de apneia e à imersão em distintas posições corporais

Monitoring internal load parameters during competitive synchronized swimming duet routines in elite athletes.

The aim of the study is to compare the heart rate (HR) and rate of perceived exertion (RPE) responses as internal load indicators while performing duet routines during training and competition, both in the technical and free programs of synchronized swimming (SS). Participants were 10 SS Olympic medalists (age, 17.4 ± 3.0 years; height, 164.0 ± 6.1 cm; body mass, 52.0 ± 6.4 kg; training, 36.3 ± 6.2 h·wk; experience, 9.2 ± 2.6 years). They were monitored while performing the same technical duet or free duet, during a training session (T) and during an official competition (C). Heart rate was continuously monitored. Rate of perceived exertion was assessed using the Borg CR10 scale. Heart rate responses during T and C were almost identical: pre-exercise mean HR (b·min) was 130.5 ± 13.9 (T) and 133.6 ± 7.7 (C) and quickly increased yielding mean peak values of 184.8 ± 5.8 (T) and 184.8 ± 6.6 (C), with interspersed bradycardic events down to 86.6 ± 4 (T) and 86.3 ± 5 (C). Routines were perceived as "hard" to "extremely hard" by the swimmers in both conditions, and mean RPE scores (0-10+) were equally high during C (7.9 ± 1.2) and T (7.5 ± 1.2) (p = 0.223). Rate of perceived exertion inversely correlated with minimum (R = -0.545; p = 0.008) and mean HR (R = -0.452; p = 0.026) and positively correlated with HRrange (R = 0.520; p = 0.011). The internal load imposed by SS duets performed during training is virtually identical to that elicited in a real competitive situation. Therefore, practicing competitive routines is suitable for developing and maintaining the cardiovascular fitness that is needed for specific conditioning in elite synchronized swimmers, with the added value of favoring exercise automaticity, interindividual coordination, and artistic expression simultaneously.

Physiological responses in relation to performance during competition in elite synchronized swimmers.

PURPOSE: We aimed to characterize the cardiovascular, lactate and perceived exertion responses in relation to performance during competition in junior and senior elite synchronized swimmers. METHODS: 34 high level senior (21.4 ± 3.6 years) and junior (15.9 ± 1.0) synchronized swimmers were monitored while performing a total of 96 routines during an official national championship in the technical and free solo, duet and team competitive programs. Heart rate was continuously monitored. Peak blood lactate was obtained from serial capillary samples during recovery. Post-exercise rate of perceived exertion was assessed using the Borg CR-10 scale. Total competition scores were obtained from official records. RESULTS: Data collection was complete in 54 cases. Pre-exercise mean heart rate (beats·min(-1)) was 129.1 ± 13.1, and quickly increased during the exercise to attain mean peak values of 191.7 ± 8.7, with interspersed bradycardic events down to 88.8 ± 28.5. Mean peak blood lactate (mmol·L(-1)) was highest in the free solo (8.5 ± 1.8) and free duet (7.6 ± 1.8) and lowest at the free team (6.2 ± 1.9). Mean RPE (0-10+) was higher in juniors (7.8 ± 0.9) than in seniors (7.1 ± 1.4). Multivariate analysis revealed that heart rate before and minimum heart rate during the routine predicted 26% of variability in final total score. CONCLUSIONS: Cardiovascular responses during competition are characterized by intense anticipatory pre-activation and rapidly developing tachycardia up to maximal levels with interspersed periods of marked bradycardia during the exercise bouts performed in apnea. Moderate blood lactate accumulation suggests an adaptive metabolic response as a result of the specific training adaptations attributed to influence of the diving response in synchronized swimmers. Competitive routines are perceived as very to extremely intense, particularly in the free solo and duets. The magnitude of anticipatory heart rate activation and bradycardic response appear to be related to performance variability.