Race Dynamics in Triathlon Mixed-Team-Relay Meaningfully Changes with The New Regulation Towards Paris 2024.

Mixed-Team-Relay (MTR) triathlon is a novel Olympic discipline whose performance determinants and tactical behaviors have barely been studied. Additionally, a regulatory change has been made to the male and female relay order for the Paris 2024 Olympics. Therefore, this study aimed to determine the performance determinants and race dynamics as a function of competitive level on the new regulated MTR triathlon. Results from 129 national teams, (516 elite triathletes) across five MTR World Triathlon Series and two MTR European Championships in 2022 and 2023, were analyzed. Split times, average speeds, time behind the race leader (gap), partial and finishing positions, pack position as well as the rank positions of every segment, relay leg, and overall race were computed. Decision tree analyses were conducted as a predictive method for the overall results, and correspondence analyses were conducted to examine the relationship between the different relay legs and segments and the finishing positions. The performance of the fourth leg was the most relevant for overall result (30%), as well as the fourth running leg (16%) and the female legs performance (7%). Medallist relay teams were characterized by displaying a differential speed lower than 0.5 and 0.83 km/h, respectively, from the best-ranking athletes in the Legs 1 and 4. Furthermore, staying in the front pack after the second swimming leg showed a great relationship with achieving a medal position. New MTR triathlon rules shift race dynamics, emphasizing individual efforts in cycling and swimming, while maintaining the crucial importance of running.

Vision-Based System for Automated Estimation of the Frontal Area of Swimmers: Towards the Determination of the Instant Active Drag: A Pilot Study.

Swimmers take great advantage by reducing the drag forces either in passive or active conditions. The purpose of this work is to determine the frontal area of swimmers by means of an automated vision system. The proposed algorithm is automated and also allows to determine lateral pose of the swimmer for training purposes. In this way, a step towards the determination of the instantaneous active drag is reached that could be obtained by correlating the effective frontal area of the swimmer to the velocity. This article shows a novel algorithm for estimating the frontal and lateral area in comparison with other models. The computing time allows to obtain a reasonable online representation of the results. The development of an automated method to obtain the frontal surface area during swimming increases the knowledge of the temporal fluctuation of the frontal surface area in swimming. It would allow the best monitoring of a swimmer in their swimming training sessions. Further works will present the complete device, which allows to track the swimmer while acquiring the images and a more realistic model of conventional active drag ones.

Periodization and Block Periodization in Sports: Emphasis on Strength-Power Training-A Provocative and Challenging Narrative.

ABSTRACT: Stone, MH, Hornsby, WG, Haff, GG, Fry, AC, Suarez, DG, Liu, J, Gonzalez-Rave, JM, and Pierce, KC. Periodization and block periodization in sports: emphasis on strength-power training-a provocative and challenging narrative. J Strength Cond Res 35(8): 2351-2371, 2021-Periodization can be defined as a logical sequential, phasic method of manipulating fitness and recovery phases to increase the potential for achieving specific performance goals while minimizing the potential for nonfunctional over-reaching, overtraining, and injury. Periodization deals with the micromanagement of timelines and fitness phases and is cyclic in nature. On the other hand, programming deals with the micromanagement of the training process and deals with exercise selection, volume, intensity, etc. Evidence indicates that a periodized training process coupled with appropriate programming can produce superior athletic enhancement compared with nonperiodized process. There are 2 models of periodization, traditional and block. Traditional can take different forms (i.e., reverse). Block periodization has 2 subtypes, single goal or factor (individual sports) and multiple goals or factors (team sports). Both models have strengths and weaknesses but can be "tailored" through creative programming to produce excellent results for specific sports.

SwimOne. New Device for Determining Instantaneous Power and Propulsive Forces in Swimming.

The propulsive forces and instantaneous power that are generated by a swimmer have a great influence on the swimming performance. This works presents a new device, called SwimOne, for measuring propulsive force and estimating the instantaneous power of the swimmer. In addition, the detailed prototype is able to exert a customizable opposition force to the swimmer for training purpose. The conceptual idea is presented by describing the differential equation of the swimmer and the protocol for a factible estimation of the instantaneous power. The variables that are to be measured and estimated are identified and, consequently, the sensor and actuator systems can be selected. The high-level and detailed designs of the prototype are presented together with the protocol that is carried out in order to validate the sensor and actuation systems. The device is able to monitor the variables of interest of the swimmer together with the propulsive force and instant power. Finally, some experiments are carried out providing the results of several participants swimming in crawl, backstroke, butterfly, and breaststroke styles in the presence of different opposition force. The preliminary results show that SwimOne is valid for measuring instantaneous force and power with different loads in swimming.

Effects of Continuous and Interval Training on Running Economy, Maximal Aerobic Speed and Gait Kinematics in Recreational Runners.

The purpose of this study was to evaluate the effects on running economy (RE), V[Combining Dot Above]O2max, maximal aerobic speed (MAS), and gait kinematics (step length [SL] and frequency, flight and contact time [CT]) in recreational athletes, with 2 different training methods, Interval and Continuous (CON). Eleven participants were randomly distributed in an interval training group (INT; n = 6) or CON training group (CON; n = 5). Interval training and CON performed 2 different training programs (95-110% and 70-75% of MAS, respectively), which consisted of 3 sessions per week during 6 weeks with the same external workload (%MAS × duration). An incremental test to exhaustion was performed to obtain V[Combining Dot Above]O2max, MAS, RE, and gait variables (high speed camera) before and after the training intervention. There was a significant improvement (p ≤ 0.05) in RE at 60 and 90% of MAS by the CON group; without changes in gait. The INT group significantly increased MAS and higher stride length at 80, 90, and 100% of MAS and lower CT at 100% of MAS. As expected, training adaptations are highly specific to the overload applied with CON producing improvements in RE at lower percentage of MAS whereas INT produces improvements in MAS. The significantly increased stride length and decreased CT for the INT group are an important outcome of favorable changes in running gait.

Optimization of Sprint Training Among European Coaches: Quality Over Quantity.

PURPOSE: To describe how high-level European sprint coaches (from 100 to 400 m) work to improve important factors associated with the quality of the holistic training process and the quality of the specific training session. METHODS: A descriptive analysis was conducted using questionnaires from 31 European elite sprint coaches (ie, training athletes defined as tiers 3, 4, and 5) who participated voluntarily. RESULTS: The coaches used traditional periodization (45%) with a 10- to 15-day tapering phase (48%) that includes a reduction in volume, maintenance of intensity, and focus on correct technical execution. In the 3 mesophases, coaches prioritized the basic development of strength and sprint work in the first phases of the season and emphasized more sprint-specific work in the competitive phase. Before sessions, adjustments were made based on factors such as psychological (77%), technical (48%), and physical (39%) parameters. In-session load management relies on a combination of objective and subjective measures (55%), in which the dialogue with athletes (65%) was regarded as the main resource. Feedback during and after sessions covers technical (54%), psychological (48%), and physical (35%) aspects. Recovery protocols after sessions mainly involve rest and professional guidance (42%). For performance assessment and testing, coaches utilize countermovement jump (52%), force-velocity profile (45%), and 30-m flying (61%) as main tools. CONCLUSIONS: European sprint coaches demonstrated a comprehensive approach to planning and management, shedding light on the multifaceted nature of their training methodologies and the diverse tools employed for athlete testing and monitoring.

Countermovement-Jump and Pull-Up Performance Before and After a Swimming Race in Preparatory and Competitive Phases of a Swimming Season.

PURPOSE: Monitoring performance athletes' training responses can be efficiently completed at competitive events. This study aimed to explore the changes in swimming, countermovement-jump (CMJ), and pull-up (PU) performance following training across a competitive phase, as well as immediately before and after each race. METHODS: Fourteen well-trained male sprint/middle-distance swimmers (height 179 [7] cm, mass 70 [8] kg, age 18 [2] y), from 3 regional training groups, completed CMJ and PU tests before and after the national competitions in October and May, when race performance was also assessed. RESULTS: Swimming race performance was significantly improved from before the national competitions in October to after the national competitions in May (1.8% [3.2%], P = .044, d = 0.60, moderate effect). Although there were no significant changes in PU velocity, CMJ performance significantly improved from before the national competitions in October to after the national competitions in May (mean difference 2.29 cm, P = .004, d = 3.52) and showed before-to-after race decreases (mean difference -1.64 cm, P = .04, d = 2.28). CONCLUSION: Swimming performance and CMJ performance improved as the season progressed, although these improvements were not directly correlated. PU performance did not appear to be sensitive to training or race-induced fatigue, in contrast to CMJ, in this group of male swimmers.

Body Composition and Dietary Intake Profiles of Elite Iranian Swimmers and Water Polo Athletes.

BACKGROUND: This study aimed to conduct a detailed and comparative analysis of body composition and dietary habits in elite swimming and water polo athletes. Through the examination of these key parameters, this study seeks to compare the dietary intake of these two distinct aquatic sports disciplines. METHODS: A total of 10 top-level swimmers and 13 water polo athletes participated in anthropometric and body composition assessments, as well as a detailed analysis of nutritional intake. To compare the two groups, an independent samples t-test was used, and variance homogeneity was checked using Levene's test. The effect size of the group differences was evaluated using Hedges' g. RESULTS: Water polo athletes showed significantly greater height (189.4 ± 2.9 vs. 186.5 ± 2.0 cm, p = 0.013), body mass index (24.3 ± 1.4 vs. 22.1 ± 0.5 kg/m2, p < 0.001), fat-free mass (62.9 ± 1.4 vs. 61.1 ± 1.38 kg, p < 0.001), skeletal muscle mass (47.1 ± 1.3 vs. 43.9 ± 1.6 kg, p < 0.001), and overall weight (86.9 ± 6.9 vs. 76.7 ± 2.2 kg, p < 0.001) in comparison to swimmers. Swimmers consumed greater amounts of mean daily energy (60.0 ± 1.0 vs. 39.0 ± 1.0 kcal/kg, p < 0.001), carbohydrate (7.8 ± 0.3 vs. 4.4 ± 0.5 g/kg, p < 0.001), protein (1.7 ± 0.5 vs. 1.4 ± 0.5 g/kg, p < 0.001), and fat (2.4 ± 0.5 vs. 1.7 ± 0.5 g/kg, p < 0.001) compared to water polo athletes. CONCLUSION: Our findings highlight the need for differentiated targeted nutritional interventions to enhance athletic performance in different types of water sports. Compared to water polo athletes, swimmers consumed significantly higher amounts of calories, matching their increased calorie demand from their specific training regime. However, this is an observational study and the differential needs of energy and macronutrients in water sports should be confirmed by studies with energy expenditure measurements.

Efficacy of two different stretch training programs (passive vs. proprioceptive neuromuscular facilitation) on shoulder and hip range of motion in older people.

The aim of this study was to determine the influence of 2 methods of stretch training (passive and proprioceptive neuromuscular facilitation [PNF]) on range of motion (ROM) in older people between the age of 60 and 70 years over a period of 13 weeks. Fifty-four participants (39 women and 15 men) were divided into 3 groups: passive (n = 17; 66.5 ± 6.5 years), PNF (n = 17; age, 64.7 ± 4.0 years old), and control (n = 17; age, 66.4 ± 4.5 years). The subjects trained 2 times per week on nonconsecutive days for 13 weeks. Each training session included 2 flexibility exercises focused on the shoulder and hip joints. The PNF group performed 6 seconds of passive stretching, 3 seconds of muscular contractions, and 2 seconds of relaxation. The passive group performed 10 seconds of stretching and 5 seconds of relaxation. This sequence was repeated 3 times by each group. The control group did not perform any stretching. In the PNF group, there was an increase in hip ROM (p < 0.001) between pretest and posttest in the passive group and an improvement (p < 0.001) was observed between pretest and posttest, whereas in the control group, there was a significant decrease (p < 0.01) in hip ROM between pretest and posttest. In shoulder ROM, there was an increase (p < 0.001) between pretest and posttest in the passive group and an improvement (p < 0.001) was observed between pretest and posttest in the PNF group. There were no changes in shoulder ROM between pretest and posttest in the control group. The analysis of variance showed significant differences in hip and shoulder ROM between passive and control groups and PNF and control groups, but no significant differences were found between passive and PNF. The main finding was that the ability of physically active older people to increase ROM in response to stretching techniques is similar for both passive and PNF techniques.

Reverse Periodization for Improving Sports Performance: A Systematic Review.

BACKGROUND: Reverse periodization is commonly touted as a salient planning strategy to improve sport performance in athletes, but benefits have not been clearly described. OBJECTIVES: We sought to identify the main characteristics of reverse periodization, and the influence of training volume and periodization models on enhancing physiological measures and sports performance. DESIGN: Systematic review. METHODS: The electronic databases Scopus, PubMed and Web of Science were searched using a comprehensive list of relevant terms. RESULTS: A total of 925 studies were identified, and after removal of duplicates and studies based on title and abstract screening, 17 studies remained, and 11 finally included in the systematic review. There was a total of 200 athletes in the included studies. Reverse periodization does not provide superior performance improvements in swimming, running, muscular endurance, maximum strength, or maximal oxygen uptake, compared to traditional or block periodization. The quality of evidence levels for the reverse periodization studies was 1b (individual randomized controlled trial) for two investigations, 2b (individual cohort study) for the remaining studies and a mean of 4.9 points in the PEDro scale (range 0-7). CONCLUSIONS: It appears that reverse periodization is no more effective than other forms of periodization in improving sports performance. More comparative studies on this alternative version of periodization are required to verify its effectiveness and utility across a range of endurance sports.

Which variables may affect underwater glide performance after a swimming start?

The underwater phase is perhaps the most important phase of the swimming start. To improve performance during the underwater phase, it is necessary to improve our understanding of the key variables affecting this phase. The main aim of this study was to identify key kinematic variables that are associated with the performance of an underwater glide of a swimming start, when performed at streamlined position without underwater undulatory swimming. Sixteen experienced swimmers performed 48 track starts and 20 kinematic variables were analysed. A multiple linear regression analysis was carried out to explore the relationship between glide performance (defined as glide distance) and the variables that may affect glide performance. Four variables in the regression model were identified as good predictors of glide distance: flight distance; average velocity between 5 m and 10 m; and maximum depth of the hip. The results of the present study help improve our understanding of underwater glide optimisation and could potentially facilitate improvement of overall start performance.

Seasonal changes in jump performance and body composition in women volleyball players.

The present study aimed to evaluate the effects of different resistance training programs on jump performance and body composition of female volleyball players of the highest Spanish division league over 24 weeks of training. Ten female volleyball players (27.41 ± 4.94 years; 72.2 ± 8.5 kg; 179.7 ± 6.4 cm) completed 24 weeks of training and testing using a linear periodization, progressing from general conditioning (weeks 1-4), to hypertrophy (weeks 5-8), then to maximum strength and power (weeks 9-16) and concluding with a specific strength training (weeks 17-24). Body composition was measured using bioelectrical-impedance analysis, and neuromuscular capacity was estimated by squat jump, countermovement jump, Abalakov jump, and 2 repetition maxima (2RM). After initial evaluation (PRE), the players were tested on 3 different occasions (POST: fourth week, POST 1: eighth week and POST 2: 24th week) of the training cycle. Muscle mass increased on (4.5%, p < 0.05) and fat-free mass (4.38%, p < 0.05), whereas fat percent decreased (13.90%, p < 0.05). All neuromuscular performance tests were increased from PRE to POST 2 (ranging from 17.64 to 20.89%, p < 0.01) and from POST 1 to POST 2 (ranging from 4.62 to 7.56% p < 0.01). The results suggest that the volleyball players studied continued improving power and strength capacity together with body composition during the course of the study. Finally, as major application, these data provide normative and performance standards for female volleyball players.

Changes in vertical jump height, anthropometric characteristics, and biochemical parameters after contrast training in master athletes and physically active older people.

The purpose of this study was to determine the effects of 16 weeks of contrast training (CT) on older adults (with different levels of physical conditioning) in vertical jump performance (squat jump [SJ], countermovement jump [CMJ], CMJ during 15 seconds [CMJ15], depth jump [DJ]), body weight, fat percentage, muscle mass (MM), muscle cross-sectional area ([CSA] of the arm and thigh) and biochemical parameters (creatine kinase [CK], creatinine, and urea). Sixteen older (63.55 ± 6.89 years) recreational master runners (A) and 16 physically active older people (60.30 ± 5.18 years) though not athletes (NA), participated in the CT using a combination of heavy-resistance and explosive exercise. The dependent variables were measured pretraining and posttraining. The CT resulted in significant improvements (α = 0.05) for both groups in jump performance. The SJ height improved in NA by 21.68% and in A by 21.81%, the CMJ height increased in NA by 21.51% and in A by 14.81%, the DJ height increased in NA by 26.45% and in A by 7.43%, and CMJ15 increased in NA by 6.20% and in A by 6.17%). Significant improvements in MM (16.44% in NA and 14.78% in A), thigh CSA (19.68% in NA and 21.67% in A), and arm CSA (7.43% in NA and 5.52% in A), and significant decreases in creatinine (8.65%) and CK (25.49%) in A were observed. In conclusion, CT improved vertical jump performance and MM in both groups, regardless of the training history and current physical activity of each group. These improvements were accompanied by a slight decrease in body fat but no changes in total body weight. These findings suggest that CT can have a significant effect on maximal jump height and MM in NA and A.

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.

Older or Wiser? Age and Experience Trends in 20 Years of Olympic and World Swimming Championships Open Water 10-km Races.

The aims of the present research were to estimate the age of peak performance (APP) and to examine the role of previous experience at the world-level open water race performances. Finishing positions and age of swimmers (639 females and 738 males) in the 10-km events of World Championship (WCH) and Olympic Games (OG) from 2000 to 2019 were obtained from the official results websites. Years of previous experience were computed using the number of previous participations in WCH or OG. APP was estimated using quadratic models of the 10th percentile top race positions and resulted in 28.94 years old for males (R2 = 0.551) and 27.40 years old for females (R2 = 0.613). Regression analysis revealed an improvement of 1.36 or 8.19 finishing positions for each additional year of age or experience, respectively (R2 = 0.157). However, significant differences (p < 0.001) between age and experience showed that the swimmer's age became less relevant for performance as years of experience increased. These results, in terms of age, are in line with other mass-start disciplines of similar duration (≈2 h) and, in terms of experience, confirm the importance of previous participation in improving tactical decision making during open water races.

Periodization and Programming for Individual 400 m Medley Swimmers.

Knowledge in the scientific domain of individual medley (IM) swimming training over a competitive season is limited. The purpose of this study was to propose a detailed coaching framework incorporating the key elements of a periodized training regimen for a 400 m IM swimmer. This framework was based on the available coaching and scientific literature and the practical experience and expertise of the collaborating authors. The season has been divided in two or three macrocycles, further divided in three mesocycles each (six or nine mesocycles in total), in alignment with the two or three main competitions in each macrocycle. The principal training contents to develop during the season expressed in blood lactate zones are: aerobic training (~2 mmol·L-1), lactate threshold pace (~4 mmol·L-1) and VO2max (maximum oxygen uptake) (~6 mmol·L-1). Strength training should focus on maximum strength, power and speed endurance during the season. Altitude training camps can be placed strategically within the training season to promote physiological adaptation and improvements in performance. A well-constructed technical framework will permit development of training strategies for the 400 m IM swimmer to improve both training and competitive performance.

Effects of Dry-Land Training Programs on Swimming Turn Performance: A Systematic Review.

Swimming coaches have prescribed dry-land training programs over the years to improve the overall swimming performance (starts, clean swimming, turns and finish). The main aim of the present systematic review was to examine the effects of dry-land strength and conditioning programs on swimming turns. Four online databases were scrutinised, data were extracted using the Preferred PRISMA guidelines and the PEDro scale was applied. A total of 1259 articles were retrieved from database searches. From the 19 studies which were full-text evaluated, six studies were included in the review process. The review indicated that plyometric, strength, ballistic and core training programs were implemented for improving swimming turn performance. Strength, ballistic and plyometric training focusing on neural enhancement seem to be effective for improving swimming turn performance. The data related to training of the core were not conclusive. Coaches should consider incorporating exercises focusing on improving the neuromuscular factor of the leg-extensor muscles into their daily dry-land training programs. More researches are needed to provide a better understanding of the training methods effects and training organisations for improving swimming turn performance.

The Effects of Interval and Continuous Training on the Oxygen Cost of Running in Recreational Runners: A Systematic Review and Meta-analysis.

BACKGROUND: Oxygen cost of running is largely influenced by endurance training strategies, including interval and continuous training. However, which training method better reduces the oxygen cost remains unknown. OBJECTIVE: This study aimed to systematically review the scientific literature and performs a meta-analysis to address the effects of different endurance training modalities on the oxygen cost of running. METHODS: A literature search on 3 databases (MEDLINE, SPORTDiscus and Web of Science) was conducted on February 28, 2019. After analysing 8028 resultant articles, studies were included if they met the following inclusion criteria: (a) studies were randomised controlled trials, (b) studies included trained runners without previous injuries (c) interventions lasted at least 6 weeks, with participants allocated to Interval (INT) or Continuous (CON) groups, and (d) oxygen cost was assessed pre- and post-training intervention. Six studies (seven trials) met the inclusion criteria and were included in the meta-analysis. This resulted in 295 participants (n = 200 INT; n = 95 CON training method). Standardised mean difference with 95% confidence intervals (CI) between INT and CON conditions and effect sizes were calculated. To assess the potential effects of moderator variables (such as, age, VO2max of participants, number of weeks of intervention) on main outcome (oxygen cost of running), subgroup analyses were performed. RESULTS: Comparing changes from pre- to post-intervention, oxygen cost improved to a greater extent in CON when compared to INT interventions (0.28 [95% CI 0.01, 0.54], Z = 2.05, p = 0.04, I2 = 30%). Oxygen cost improvements were larger in participants with higher VO2max (≥ 52.3 ml kg-1 min-1) (0.39 [95% CI 0.06, 0.72], Z = 2.34, p = 0.02), and in programs greater or equal to 8 weeks (0.35 [95% CI 0.03, 0.67], Z = 2.13, p = 0.03). When the total volume per week of INT was ≥ 23.2 min, there was a significant improvement favorable to CON (0.34 [95% CI 0.01, 0.61], Z = 2.02, p = 0.04). CONCLUSION: Continuous training seems, overall, a better strategy than interval training to reduce the oxygen cost in recreational endurance runners. However, oxygen cost reductions are influenced by several variables including the duration of the program, runners' aerobic capacity, the intervals duration and the volume of interval training per week. Practitioners and coaches should construct training programs that include both endurance training methods shown to be effective in reducing the oxygen cost of running.

Differences in force production and EMG activity on underwater and dry land conditions in swimmers and non-swimmers.

This research aims to provide a better understanding of the swimming push-off specificity comparing force production and electromyographic (EMG) activity on squat-jumps (SJ) and countermovement-jumps (CMJ) performed underwater (similar to swimming turns push-off) and dryland conditions on two different level of expertise participants (swimmers and non-swimmers). Thirteen male swimmers and nine non-trained male sport sciences students participated in this study. Each subject carried out 10 CMJ and 10 SJ jumps in dryland (vertical) and underwater (horizontal). During these trials, force production was recorded by force platforms and muscular activity of Vastus Lateralis, Biceps Femoris, Gastrocnemius Medialis and Tibialis Anterior was analysed through EMG. A three-way ANOVA showed that swimmers increased the differences in values obtained from SJ to CMJ between dry and underwater conditions during the first impulse phase-Impulse 1 (p < 0.01), the second phase of impulse-Impulse 2 (p < 0.001) and duration from peak force to take off (p < 0.001) in contrast to non-swimmers. Patterns relating to force production and EMG were non-consistent between muscles. Jumping performance was not significantly correlated between dry land and underwater conditions; nevertheless, results emphasise that environmental constraints are decisive to define the neuro-motor response to apparently similar tasks performed in different contexts.

Assessment of sensory sensitivity through critical flicker fusion frequency thresholds after a maximum voluntary apnoea.

INTRODUCTION: The influence of acute exercise on sensory sensitivity (SS) differs according to the type and duration of exercise performed. In the present study, we assessed changes on SS soon after a maximal dynamic apnoea. METHODS: Thirty-nine experienced male breath-hold divers were recruited. Critical flicker fusion frequency (CFFF) thresholds were used to measure SS. Thresholds were determined before and after a maximal dynamic apnoea. Immediately after surfacing, heart rate and oxygen saturation (SpO2) were recorded for two minutes. RESULTS: After maximal dynamic apnoea, SpO2 was significantly decreased (from mean 97.3% pre-dive to mean 63.1% post-dive; P < 0.0001; η2 P = 0.86), but this acute hypoxaemia did not trigger changes in SS (post-dive value 102% of baseline; P = 0.22; η2 P = 0.03). Pearson correlation analysis revealed a moderate association between SS with swimming speed (r = 0.423) and apnoea time (r = -0.404). CONCLUSIONS: A maximal dynamic apnoea did not produce changes in central nervous system fatigue or cortical arousal. We found no relationship between the hypoxaemia level reached after a maximal apnoea and changes in the CFFF thresholds. This study suggests that the time of exposure to hypoxia during a maximal voluntary apnoea is not enough to produce changes in SS.