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A well-planned periodized approach endeavors to allow road cyclists to achieve peak performance when their most important competitions are held. Purpose: To identify the main characteristics of periodization models and physiological parameters of trained road cyclists as described by discernable training intensity distribution (TID), volume, and periodization models. Methods: The electronic databases Scopus, PubMed, and Web of Science were searched using a comprehensive list of relevant terms. Studies that investigated the effect of the periodization of training in cyclists and described training load (volume, TID) and periodization details were included in the systematic review. Results: Seven studies met the inclusion criteria. Block periodization (characterized by employment of highly concentrated training workload phases) ranged between 1- and 8-week blocks of high-, medium-, or low-intensity training. Training volume ranged from 8.75 to 11.68 h·wk–1 and both pyramidal and polarized TID were used. Traditional periodization (characterized by a first period of high-volume/low-intensity training, before reducing volume and increasing the proportion of high-intensity training) was characterized by a cyclic progressive increase in training load, the training volume ranged from 7.5 to 10.76 h·wk–1, and pyramidal TID was used. Block periodization improved maximum oxygen uptake (VO2max), peak aerobic power, lactate, and ventilatory thresholds, while traditional periodization improved VO2max, peak aerobic power, and lactate thresholds. In addition, a day-by-day programming approach improved VO2max and ventilatory thresholds. Conclusions: No evidence is currently available favoring a specific periodization model during 8 to 12 weeks in trained road cyclists. However, few studies have examined seasonal impact of different periodization models in a systematic way.

Purpose: This review aimed to determine (1) performance and training characteristics such as training intensity distribution (TID), volume, periodization, and methods in highly trained/elite distance runners and (2) differences in training volume and TID between event distances in highly trained/elite distance runners. Methods: A systematic review of the literature was carried out using the PubMed/MEDLINE, Scopus, and Web of Science databases. Results: Ten articles met the inclusion criteria. Highly trained/elite distance runners typically follow a pyramidal TID approach, characterized by a decreasing training volume from zone 1 (at or below speed at first ventilatory/lactate threshold [LT]) to zone 2 (between speeds associated with either both ventilatory thresholds or 2 and 4 mmol·L−1 LTs [vLT1 and vLT2, respectively]) and zone 3 (speed above vVT2/vLT2). Continuous-tempo runs or interval training sessions at vLT2 in zone 2 (ie, medium and long aerobic intervals) and those in zone 3 (ie, anaerobic or short-interval training) were both used at least once per week each in elite runners, and they were used to increase the number of either vLT2 or z3 sessions to adopt either a pyramidal or a polarized approach, respectively. More pyramidal- and polarized-oriented approaches were used by marathoners and 1500-m runners, respectively. Conclusions: Highly trained and elite middle- and long-distance runners are encouraged to adopt a traditional periodization pattern with a hard day–easy day basis, consisting in a shift from a pyramidal TID used during the preparatory and precompetitive periods toward a polarized TID during the competitive period.

BACKGROUND: The determination of critical power (CP) during training is a useful tool monitoring performance progression and to demarcate training intensity zones. The aims of this study were: 1) to compare CP with varied effort short, medium and long intervals (SML-INT) with a field CP test; 2) to assess if SML-INT is an effective way to improve CP.METHODS: Seven male cyclists completed a 4-week training period. Before and after the training period, an assessment of CP was conducted using a 2 and 3-parameter model. Furthermore, during the training period, mean maximal power (MMP) achieved during 30-s, 1-, 3- and 7-min intervals, were used to calculate CP.RESULTS: CP was increased by 5% after four weeks. A significant difference in CP and W' (the finite amount of work which can be performed above CP) in pre-test values and all power outputs analyzed (P

This study aimed to address the effects of increased longitudinal bending stiffness (LBS) on running economy (RE) and running biomechanics. A systematic search on four electronic databases (Pubmed, WOS, Medline and Scopus) was conducted on 26 May 2021. Twelve studies met the inclusion criteria and were included. Standardised mean difference with 95% confidence intervals (CI) between footwear with increased LBS vs. non-increased LBS conditions and effect sizes were calculated. To assess the potential effects of moderator variables (type and length plate, increased LBS, shoe mass and running speed) on the main outcome variable (i.e. RE), subgroup analyses were performed. Increased LBS improved RE (SMD = -0.43 [95% CI -0.58, -0.28], Z = 5.60, p < 0.001) compared to non-increased LBS. Significant increases of stride length (SMD = 0.29 [95% CI 0.10, 0.49], Z = 2.93, p = 0.003) and contact time (SMD = 0.17 [95% CI 0.03, 0.31], Z = 2.32, p = 0.02) were found when LBS was increased. RE improved to a greater degree at higher running speeds with footwear with increased LBS. RE improved 3.45% with curve plate compared to no-plate condition without improvements with flat plate shoes. When shoe mass was matched between footwear with increased LBS vs. non-increased LBS conditions, RE improved (3.15%). However, when shoe mass was not controlled (experimental condition with ∼35 grams extra), a significant small improvement was found. These RE improvements appear along with an increase of stride length and contact time. Shoe mass, type of plate (flat or curve) and running speed should be taken into consideration when designing a shoe aimed at improving long-distance running performance.

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. pre-print 153 KB

A well-planned periodized approach allows swimmers to achieve peak performance at the major national and international competitions. Purpose: To identify the main characteristics of endurance training for highly trained swimmers described by the training intensity distribution (TID), volume, and periodization models. Methods: The electronic databases Scopus, PubMed, and Web of Science were searched using a comprehensive list of relevant terms. Studies that investigated the effect of the periodization of training in swimming, with the training load (volume, TID) and periodization reported, were included in the systematic review. Results: A total of 3487 studies were identified, and after removal of duplicates and elimination of papers based on title and abstract screening, 17 articles remained. A further 8 articles were excluded after full text review, leaving a final total of 9 studies in the systematic review. The evidence levels were 1b for intervention studies (n = 3) and 2b for (observational) retrospective studies (n = 6). The sprint swimmers typically followed a polarized and threshold TID, the middle-distance swimmers followed a threshold and pyramidal TID, and the long-distance swimmers primarily followed a pyramidal TID. The periodization model identified in the majority of studies selected is characterized by wave-like cycles in units like mesocycles to promote physiological adaptations and skill acquisition. Conclusions: Highly trained swimmers follow a training volume and TID based on their primary event. There is a need for further experimental studies on the effects of block and reverse periodization models on swimming performance. Although observational studies of training have limited evidence, it is unclear whether a different training/periodization approach would yield better results.

A breakpoint in a portable near-infrared spectroscopy (NIRS) derived deoxygenated haemoglobin (deoxy[Hb]) signal during an incremental VO2max running test has been associated with the second ventilatory threshold (VT2) in healthy participants. Thus, the aim was to examine the association between this breakpoint (NIRS) and VT2 in well-trained runners. Gas exchange and NIRS data were collected during an incremental VO2max running test for 10 well-trained runners. The breakpoint calculated in oxygen saturation (StO2) and the VT2 were determined and compared in terms relative to %VO2max, absolute speed, VO2, and maximum heart rate (HRmax). There were no significant differences (p>0.05) between the breakpoint in StO2 and VT2 relative to %VO2max (87.00±6.14 and 88.28 ± 3.98 %), absolute speed (15.70±1.42 and 16.10±1.66 km·h−1), VO2 (53.71±15.17 and 54.66±15.57 ml·kg−1·min−1), and%HRmax (90.90±4.17 and 91.84±3.70%). There were large and significant correlations between instruments relative to%VO2max (r=0.68, p

The aim of this study was to assess the effect of recovery period during long interval training (IT) on mechanical, physiological, perceptive, and neuromuscular parameters. Six men and six women trained runners (23.82 ± 7.83years; 56.27 ± 8.95kg; 167.55 ± 9.77cm) performed three treadmill interval sessions (4x4min) at 1% incline with 1min, 2min or self-selected recovery periods (SSrecovery) at highest possible average running speed. Velocity and distance increased by 2.5% (p

The aim of this study was to determine the influence of running wide on bends regarding intermediate changes of position, dispersion of athletes, and speed relative to season best (SB) between medalists and non-medalists in men’s and women’s 800 m championship finals. Extra distance covered on bends was measured using official videos. The total distance run was calculated and described as the minimum calculable distance. Theoretical mean speeds, theoretical finishing times and theoretical finishing positions were calculated. In addition, intermediate and total changes of position (on bends and straights) and dispersion between athletes in each 100-m segment were calculated. Finishing times and segment times were calculated relative to SB. Theoretical finishing times were faster than official finishing times (p

Objetivo: Analizar la influencia de diferentes intensidades de nado en los sectores de ciclismo y carrera a pie y en el rendimiento final del triatlón sprint. Métodos: Siete triatletas sub23 y Absolutos (altura de 1,74 ± 0,04 m, peso de 70,82 ± 6,76 kg, edad de 23,42 ± 3,25 años, VO2 max de 63,54 ± 5,23 ml·kg-1·min-1) participaron en este estudio. Realizaron tres triatlones completos a intensidades de nado diferentes (70%, 80% y 90% de un test de 750m previo). Se midió la frecuencia cardíaca y el lactato al finalizar cada sector y el triatlón completo. Resultados: La intensidad de nado del 90% obtuvo el mejor rendimiento final. El lactato y frecuencia cardíaca en el sector de nado para esta condición incrementó significativamente, sin diferencias en los sectores siguientes. Conclusiones: Basándonos en la muestra estudiada, el rendimiento final en un triatlón sprint parece estar condicionado por la intensidad de nado, siendo el 90% la mejor intensidad observada en triatletas moderadamente entrenados.

Critical power (CP) has been redefined as the new ‘gold standard’ that represents the boundary between the heavy- and severe-exercise intensity domains and hence the maximal metabolic steady state (MMSS). However, several other “thresholds”, for instance, the maximal lactate steady state [MLSS], ventilatory thresholds [VT1, VT2] and respiratory compensation point [RCP]) have been considered synonymous with CP. This study aimed to systematically review the scientific literature and perform a meta-analysis to determine the degree of correspondence/difference between CP and MLSS, VT1, VT2 and RCP. A literature search on 2 databases (Scopus and Web of Science) was conducted on October 2, 2019. After analyzing 356 resultant articles, studies were included if they met the following inclusion criteria: (a) studies were randomized controlled trials, (b) studies included interrelations between CP and VT1, VT2, MLSS, RCP. Articles were excluded if they constituted duplicate articles or did not meet the inclusion criteria. Nine studies met the inclusion criteria and were included in this meta-analysis. This resulted in 104 participants. A random effects weighted meta-analysis with correlation coefficients was used to pool the results. The pooled correlation coefficient of CP and all thresholds analyzed was r = 0.73 (p > 0.00001). The subgroup analysis for each threshold with CP demonstrated significant correlation coefficients of r = 0.80 (95% CI [0.40; 1.21], Z = 3.90, p = 0.0001) for CP & RCP; r = 0.77 (CI 95% = [0.36; 1.18], Z = 3.71, p = 0.0002) for CP & MLSS; r = 0.76 (CI 95% = [0.31; 1.21], Z = 3.32, p = 0.0009) for CP & VT1. However, CP & VT2, r = 0.39 (CI 95% = [− 0.37; 1.15], Z = 1.01, p = 0.31) were not significantly correlated. Despite the significant correlations between CP and VT1, MLSS and RCP these variables and VT2 under- (VT1, 30%; MLSS, 11%) or over-estimated (RCP, 6%; VT2, 21%) CP. Regardless of the presence of significant correlations among CP and ventilatory or metabolic thresholds CP differs significantly from each. Thus, logically, if CP represents the best estimate of the heavy-severe exercise intensity transition none of the thresholds considered (i.e., VT1, VT2, MLSS, RCP), at least as determined in the studies analyzed herein, should be considered synonymous with such.

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.

In Spain, students pursuing a career in athletic training, physical education, or scientific evaluation of sports enroll in a bachelor’s degree in sports sciences. This degree provides knowledge and skills in a broad array of sports settings and promotes research-based interdisciplinary knowledge. However, the student’s syllabus rarely includes specific academic training on anti-doping regulations or doping prevention. The purpose of this study was to assess the anti-doping knowledge of the students undertaking a bachelor’s degree in sports sciences in Spanish universities. One thousand two hundred and thirty-three bachelor students in sport science (907 males, 322 females, and 4 participants with non-binary sex) from 26 Spanish universities completed a validated questionnaire about general anti-doping knowledge. The questionnaire is an adapted version of the Play True Quiz of the World Anti-Doping Agency and contains 37 multiple-choice questions. The score obtained in the questionnaire was transformed into a 0–100-point scale. The questionnaire was distributed among students within each university by a faculty member and it was filled out online. Students obtained a score of 65.8 ± 10.10 points (range = 32–92 points). There was an effect of the course in the score obtained (p < 0.001). Students of the first course (63.6 ± 9.5 points) had lower scores than the remaining courses (p < 0.037) while the students of the fourth course obtained the highest scores (68.7 ± 9.5 points; p < 0.019). The students with an itinerary on sports performance were the respondents with the highest anti-doping knowledge (67.2 ± 10.2) points, followed by the students with an itinerary on health (66.7 ± 9.5 points). The knowledge of basic anti-doping rules and doping prevention strategies of the bachelor students in sports sciences in Spain was suboptimal. Increasing doping prevention information in the syllabus of the bachelor’s degree in sports sciences is essential as these future professionals will directly work with populations at risk of doping.

The purpose of this analysis was to quantify the probability of achieving a top-3 finishing position during 800-m races at a global championship, based on dispersion of the runners during the first and second laps and the difference in split times between laps. Overall race times, intermediate and finishing positions and 400 m split times were obtained for 43 races over 800 m (21 men’s and 22 women’s) comprising 334 individual performances, 128 of which resulted in higher positions (top-3) and 206 the remaining positions. Intermediate and final positions along with times, the dispersion of the runners during the intermediate and final splits (SS1 and SS2), as well as differences between the two split times (Dsplits) were calculated. A logistic regression model was created to determine the influence of these factors in achieving a top-3 position. The final position was most strongly associated with SS2, but also with SS1 and Dsplits. The Global Significance Test showed that the model was significant (p < 0.001) with a predictive ability of 91.08% and an area under the curve coefficient of 0.9598. The values of sensitivity and specificity were 96.8% and 82.5%, respectively. The model demonstrated that SS1, SS2 and Dplits explained the finishing position in the 800-m event in global championships.

We present a case study of the periodized training by a world-class 400-m Individual Medley (IM) swimmer (4

The present study examines the association between the success at junior and senior level for British swimmers in World Championships (WCs). It also explores the relationships between swimming performance and the swimmers’ gender, swim stroke, distance, status (finalist, semifinalist and heats) and swimming category. Data were collected for swimmers participating in junior and/or senior World Championships (29,000 entries: 5585 swimmers) from 2006–2017. The final filtered database included only swimmers from the United Kingdom (836 entries: 141 swimmers). A descriptive analysis was made to characterize the swimmers who reached elite status in the senior category. A lineal regression model was run by gender to predict the influence of category, swim stroke, and distance in the results reached in the senior category. The results showed that the ratio of conversion from junior to senior was quite low. Females who participated in both junior and senior WCs were likely to reach top positions in the senior category. Overall, few British swimmers participated in a junior category before the senior level, but female swimmers participating in both junior and senior WCs were likely to reach top positions in the senior category. post-print 335 KB

The aim of this study was to determine the influence of body weight or lean body mass-based load on Wingate Anaerobic Test performance in male and female endurance trained individuals. Thirty-one participants (22 male cyclists and triathletes and 9 female triathletes) completed two randomized Wingate Anaerobic Test (body weight and lean body mass loads) in stationary start. There were no significant differences in power outputs variables between loads in any group. However, when comparing specific groups within the sample (e. g. cyclists vs cyclists) medium to large effect sizes were observed for Relative Mean Power Output (ES=0.53), Relative Lowest Power (ES=0.99) and Relative Power Muscle Mass (ES=0.54). Regarding gender differences, male cyclists and triathletes displayed higher relative and absolute power outputs (p

This study used a power rack device to evaluate the effects of 2 different approaches to resisted swim training loads on swimming strength and performance. Sixteen male, youth national-level swimmers (mean age, 16.22 ± 2.63 years; body height, 169 ± 10.20 cm; body mass, 61.33 ± 9.90 kg) completed a 6-week specific strength-training program, and were then randomly assigned to one of the two groups: a standard training group (GS, n = 8) and a flat pyramid-loading pattern group (GP, n = 8). Strength and power tests along with specific swimming tests (50-m crawl and 50-m competition-style time trials) were conducted at baseline (pre-test), before the third week (mid-test), and after 6 weeks of intervention (post-test). Isokinetic swim bench tests were conducted to obtain measurements of force production and power, and 1RM tests with the power rack system were conducted to measure the maximum drag load (MDL) and specific swimming power. Following 6 weeks of intervention, the mean MDL increased (p < 0.05) by 13.94%. Scores for the 50-m competition style and 50-m crawl time trials improved by 0.32% and 0.78%, respectively, in the GP; however, those changes were not statistically significant. The GS significantly increased their time in the 50-m competition style by 2.59%, and their isokinetic force production decreased by 14.47% (p < 0.05). The 6-week strength-training program performed with the power rack device in a pyramidal organization was more effective than a standard linear load organization in terms of producing improvements in the MDL; however, it did not produce significant improvements in performance. The use of a strength-training program with a pyramidal organization can be recommended for specific strength-training in young swimmers during a preparatory period. However, in our study, that program did not produce significant changes in 50-m crawl and main competition style performance.

The aims of the current study were to compare the pacing patterns of all-time 800 m, 1500 m and mile running world records (WRs) and to determine whether differences exist between sexes, and if 800 m and 1500 m WRs were broken during championship or meet races. Overall and lap times for men and women’s 800 m, 1500 m, and mile WRs from World Athletics were collected when available and subsequently compared. A fast initial 200 m segment and a decrease in speed throughout was found during 800 m WRs. Accordingly, the first 200 m and 400 m were faster than the last 200 m and 400 m, respectively (p < 0.001, 0.77 ≤ ES ≤ 1.86). The first 400 m and 409 m for 1500 m and mile WRs, respectively, were faster than the second lap (p < 0.001, 0.74 ≤ ES ≤ 1.46). The third 400 m lap was slower than the last 300 m lap and 400 m lap for 1500 m and mile WRs, respectively (p < 0.001, 0.48 ≤ ES ≤ 1.09). No relevant sex-based differences in pacing strategy were found in any event. However, the first 409 m lap was faster than the last 400 m lap for men but not for women during mile WRs. Women achieved a greater % of WRs than men during championships (80% vs. 45.83% in the 800 m, and 63.63% vs. 31.58% in the 1500 m, respectively). In conclusion, positive, reverse J-shaped and U-shaped pacing profiles were used to break 800 m, men’s mile and 1500 m, and women’s mile WRs, respectively. WRs are more prone to be broken during championships by women than men.

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. post-print 626 KB

This study compared the association between Foster’s and Banister’s TRIMP methods for quantifying internal training load and training stimuli responses. Methods: A group of twenty-two Taekwondo competitors were divided by gender and level of expertise. The athletes practiced three different types of exercises to develop the following skills: a) speed, b) power, and c) aerobic power. Results: A significant correlation was obtained between the Foster’s and Banister’s TRIMP methods for developing aerobic capacity (r =0.60, p = 0.004) and power (r = 0.52, p = 0.014). No significant correlation was suggested between training methods andspeed training (r = 0.20, p = 0.377). Conclusion: Lactate and heart rate responses to different types of exercises suggested the need for aerobic and anaerobic-based training sessions. The use of rating of perceived exertion scale-based measurements to monitor workload is recommended for Taekwondo competitors. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Centro de Investigación en Ciencias del Movimiento Humano (CIMOHU) UCR::Vicerrectoría de Docencia::Ciencias Sociales::Facultad de Educación::Escuela de Educación Física

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. 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. 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. 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). 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.

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 (SpO(2)) were recorded for two minutes. RESULTS: After maximal dynamic apnoea, SpO(2) was significantly decreased (from mean 97.3% pre-dive to mean 63.1% post-dive; P < 0.0001; η(2) 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). CONCLUSION: 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.

BACKGROUND:\ud The effect of short-term interventions using high-velocity isokinetic or plyometric exercises has not been thoroughly investigated.\ud \ud OBJECTIVE:\ud The aim of this study was to compare the effect of a lower body 3-week protocol using an isokinetic or a plyometric exercise program on strength and jump performance.\ud \ud METHODS:\ud Thirty-six non-trained men were randomly allocated to the following three groups: (i) Isokinetic only (ISO, n= 12), performed 6 sets of 10 repetitions of concentric leg extension and flexion at 300∘⋅s-1 using an isokinetic dynamometer (Biodex-System-3); (ii) Plyometric only (PLY, n= 12) performed 6 sets of 10 repetitions of vertical jump; and (iii) Control, non-training group (n= 12). A 3-week training program involving two weekly workout sessions was implemented. Pre and post intervention measurements of knee extensor and flexor maximal peak torque, total work and average power at 300∘⋅s-1 and vertical jump performance were determined.\ud \ud RESULTS:\ud Compared to baseline ISO significantly (p< 0.05) increased knee extension peak torque and average power. No other significant differences were observed at post-intervention or between groups. CONCLUSIONS: Compared to performing plyometric exercise alone, a 3-week intervention using only isokinetic training enhanced knee extensors strength. A more effective and specific neural adaptations driven by the isokinetic protocol over a short period of time could explain the observed responses.

The objective of this study was to determine the effects of high-intensity warm-ups (WUs) on performance, physiological, neuromuscular and biomechanical parameters. Three randomized cross-over 105%vVO2max time limit trials (TLimT) were performed by 11 well-trained runners following three different WU protocols. These included two experimental high-intensity variants and one control WU variant: (i) 9x20-sec level strides (105%vVO2max; 1% gradient) with 60 s of recovery (level); (ii) 6x6-sec uphill strides (105%vVO2max; 5% gradient), with the same recovery (uphill) and (iii) 7 min at 60%vVO2max as control condition (control). The uphill and level WUs resulted in a greater performance during TLimT (160.0±6.62 s and 152.64±10.88 s, respectively) compared to control WUs (144.82±6.60 s). All WU conditions reduced the energy cost (EC) of running, respiratory exchange ratio, and step frequency (SF) after the experimental and control phases of WU, while blood lactate (BLC) increased in uphill and level WUs and decreased in control WUs. Changes in kinematic variables were found without differences between WU conditions during TLimT. BLC rose at conclusion of TLimT without differences between WU conditions. Both high-intensity WUs show a longer TLimT. EC is deteriorated after the high-intensity WU exercise due to a change of substrate utilization, increase of BLC and SF. A long transient phase (18 min) is necessary to avoid impairing the performance.

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.