Acute effects of dryland muscular endurance and maximum strength training on sprint swimming performance in young swimmers.

The study examined acute effects of dryland muscular endurance (ME) and maximum strength (MS) sessions on performance, physiological, and biomechanical variables during a subsequent sprint swimming session. Twenty-seven swimmers (16.5 ± 2.6 yrs) completed three experimental conditions including: i) ME, 55% of 1-repetition maximum, ii) MS, 90% of 1-repetition maximum, and iii) control (CON, no dry-land). Twenty minutes following ME, MS and CON sessions swimmers performed a 10-s tethered swimming sprint, four by 50-m (4 × 50-m), and a 100-m front crawl sprints. Performance time, blood lactate, heart rate (HR), stroke rate (SR), stroke length (SL), stroke index (SI), and stroke efficiency (ηF) were measured during 4 × 50-m and 100-m. Hand grip strength (HG), and shoulder muscles isometric strength (ISO) were measured after each session. Mean 4 × 50-m time increased in ME compared to CON by 1.7 ± 2.7% (p = 0.01), while 100-m time was similar among conditions (p > 0.05). ISO was lower after dry-land training in all conditions (p = 0.01). Tethered force, HG, HR, SR, SL, SI, and ηF were no different between conditions (p > 0.05). Dryland ME session decrease swimming performance; however, ME and MS sessions did not affect technical ability during a subsequent maximum intensity swimming.

Effects of an International Tournament on Heart Rate Variability and Perceived Recovery in Elite Water Polo Players.

ABSTRACT: Botonis, PG, Smilios, I, Platanou, TI, and Toubekis, AG. Effects of an international tournament on heart rate variability and perceived recovery in elite water polo players. J Strength Cond Res 36(8): 2313-2317, 2022-The purpose of the study was to evaluate the effects of an international tournament participation in vagal-related heart rate variability and perceived recovery among elite water polo players. Nine elite water polo players participated in an intensified training week (pretournament) and then traveled abroad to take part in an international tournament including 3 high-competitive matches during a 4-day period. Internal workload was measured after training or competition. Morning, postwakening natural logarithm of the root mean square of successive differences (lnRMSSD) and measures of perceived recovery were obtained pretournament and daily during the tournament. Logarithm of the root mean square of successive differences was also measured 30 minutes after the completion of each match of the tournament. Logarithm of the root mean square of successive differences was suppressed after the first match ( p = 0.03, d = -0.75), compared with the first morning of the tournament, rebounded the following morning ( p = 0.03, d = 0.87), and remained unaltered until the third match. In the last morning of the tournament, LnRMSSD was higher compared with the first postmatch measurement ( p = 0.002, d = 1.57) and tended to be higher than pretournament ( p = 0.09, d = 0.81). Perceived recovery and internal workloads were lower in the tournament days compared with pretournament ( p < 0.001, d = 2.0 and p < 0.001, d = 14.0, respectively). In conclusion, heart rate variability may stabilize and progressively increase by the end of a tournament, as compared with a pretournament training period, reflecting an enhanced parasympathetic reactivation may be due to the reduced training load. By contrast, perceived recovery was suppressed indicating that other factors may also influence the overall recovery of the players.

Effect of exercise training on functional capacity and body composition in myotonic dystrophy type 2 patients.

BACKGROUND: Myotonic dystrophy type 2 (DM2) is a neuromuscular disorder characterized by myotonia and muscle weakness, with no medical treatment to prevent a decline in decline. It is unknown whether exercise training is effective in DM2. The aim of this study was to investigate the effect of exercise training on functional capacity and body composition in these patients. METHODS: Body composition and functional capacity were evaluated at the beginning (T1) and end (T2) of a 12 wk control period, and again after 16 wk of exercise training (T3) in 10 patients. RESULTS: No changes were recorded after the control period. Handgrip strength, 5× sit to stand, timed up and go, 6 min walk distance, lean body mass (LBM), and bone mineral density (BMD) increased while arterial pressure decreased after training. CONCLUSIONS: These results suggest that supervised exercise training improves functional capacity, LBM, and BMD in ambulatory DM2 patients.

The impact of daytime napping on athletic performance - A narrative review.

Mid-day napping has been recommended as a countermeasure against sleep debt and an effective method for recovery, regardless of nocturnal sleep duration. Herein, we summarize the available evidence regarding the influence of napping on exercise and cognitive performance as well as the effects of napping on athletes' perceptual responses prior to or during exercise. The existing studies investigating the influence of napping on athletic performance have revealed equivocal results. Prevailing findings indicate that following a normal sleep night or after a night of sleep loss, a mid-day nap may enhance or restore several exercise and cognitive performance aspects, while concomitantly provide benefits on athletes' perceptual responses. Most, but not all, findings suggest that compared to short-term naps (20-30 min), long-term ones (>35-90 min) appear to provide superior benefits to the athletes. The underlying mechanisms behind athletic performance enhancement following a night of normal sleep or the restoration after a night of sleep loss are not clear yet. However, the absence of benefits or even the deterioration of performance following napping in some studies is likely the result of sleep inertia. The present review sheds light on the predisposing factors that influence the post-nap outcome, such as nocturnal sleep time, mid-day nap duration and the time elapsed between the end of napping and the subsequent testing, discusses practical solutions and stimulates further research on this area.

Lactate Threshold Evaluation in Swimmers: The Importance of Age and Method.

The purpose of the study was to define the most appropriate method for the calculation of the speed corresponding to lactate threshold (sLT) in male swimmers. Eight boys and eight adolescents (age: 11.4±0.5 and 15.8±0.8 years) performed 7×200-m swimming front-crawl and after drawing the speed vs. lactate curve, the sLTs were calculated using five methods: i) the intersection of two linear regression lines, ii) visual inspection, iii) D-max, iv) D-max modified, v) intersection of combined linear and exponential regression lines. All methods were compared to the speed corresponding to maximal lactate steady state (sMLSS). Two to four 30-min efforts of continuous swimming at imposed constant pace were used for sMLSS calculation. In both groups, speed of D-max modified was similar to sMLSS (children, 1.061±0.073 vs. sMLSS: 1.071±0.072 m·s-1; p>0.05; effect size: ES=0.15, small; adolescents, 1.318±0.060 vs. sMLSS: 1.284±0.047 m·s-1; p>0.05; ES=0.64, medium). In adolescents, sLT calculated by intersection of two regression lines and by visual inspection presented medium ES (0.22-0.24) and were no different to sMLSS (1.296 ± 0.051, 1.295±0.053 m·s-1, p>0.05). When testing children, D-max modified is the most appropriate method to estimate sMLSS. The intersection of the linear regression lines and visual inspection are suggested for sMLSS determination in adolescents.

The Effect of a Surface Combat Swimming Training Program on Swimming Performance.

In this study the effect of a surface combat swimming (sCS) training program on performance in freestyle swimming and sCS was examined. Forty-five officer cadets were divided into three equivalent groups: a control group (CG), a group that was trained only with a swimsuit and fins (SF), and a group that was trained with combat uniform and equipment (UE). Groups SF and UE followed a 60-min training program with sCS for 4 weeks, 4 times per week. Before and after the training program all groups performed 4×50 and 400-m freestyle swimming, 250-m sCS with a uniform and equipment, 350-m with a swimsuit and fins, and 300-m with a swimsuit. The UE group showed improved performance in 4×50-m (mean±SD 14±9 s) and in 250-m sCS (24±14 s) (p<0.01). Both the SF group and the UE group improved in 300-m sCS, in 350-m sCS and in 400-m freestyle (p<0.05). We conclude that the training adaptations seemed to be specific, not only with regard to the activity performed, but also in terms of the actual conditions of an operation, which also include equipment.

Acute and long-term effects of two different static stretching training protocols on range of motion and vertical jump in preadolescent athletes.

This study examined the acute and long-term effects of two static stretching protocols of equal duration, performed either as a single stretch or multiple shorter duration repetitions on hip hyperextension range of motion (ROM) and single leg countermovement jump height (CMJ). Thirty female gymnasts were randomly assigned to stretching (SG) or control groups (CG). The SG performed two different protocols of static stretching, three times per week for 9 weeks. One leg performed repeated stretching (3 × 30 s with 30 s rest) while the other leg performed a single stretch (90 s). The CG continued regular training. ROM and CMJ were measured pre- and 2 min post-stretching on weeks 0, 3, 6, 9, and 3 weeks into detraining. CMJ height increased over time irrespective of group (main effect time, p = 0.001), with no statistical difference between groups (main effect group, p = 0.272). Three-way ANOVA showed that, CMJ height after stretching was not affected by either stretching protocol at any time point (p = 0.503 to 0.996). Both stretching protocols equally increased ROM on weeks 6 (10.9 ± 13.4%, p < 0.001, d = 0.42), and 9 (21.5 ± 13.4%, p < 0.001, d = 0.78), and this increase was maintained during detraining (17.0 ± 15.0%, p < 0.001, d = 0.68). No increase in ROM was observed in the CG (p > 0.874). Static stretching of long duration applied either as single or multiple bouts of equal duration, results in similar acute and long-term improvements in ROM. Furthermore, both stretching protocols do not acutely affect subsequent CMJ performance, and this effect is not influenced by the large increase in ROM and CMJ overtime.

Effect of a Carbohydrate-Electrolyte Solution on Fluid Balance and Performance at a Thermoneutral Environment in International-Level Fencers.

Chryssanthopoulos, C, Tsolakis, C, Bottoms, L, Toubekis, A, Zacharogiannis, E, Pafili, Z, and Maridaki, M. Effect of a carbohydrate-electrolyte solution on fluid balance and performance at a thermoneutral environment in international-level fencers. J Strength Cond Res 34(1): 152-161, 2020-The purpose of the study was to examine a possible effect of a carbohydrate-electrolyte (CHO-E) solution on fluid balance and performance in fencing at a thermoneutral environment. Sixteen fencers performed two 120-minute training sessions separated by 7-14 days under similar environmental conditions (temperature: 20.3° C and humidity: 45-47%). Each session consisted of 60-minute conditioning exercises followed by 10 bouts of 3 minutes against the same opponent with 3-minute interval between each bout. Participants ingested at regular intervals either a 6% CHO-E solution or an artificially sweetened water (PL) in a counterbalanced order. No difference was observed between conditions in the heart rate responses, perceived exertion, changes in plasma volume, urine specific gravity, number of bouts won or lost, or points for and against. Considerable variability was observed in body mass changes that revealed significant differences at the time level (i.e., pre- vs. post-exercise) (F1,15 = 9.31, p = 0.008, η = 0.38), whereas no difference was found between conditions (i.e., CHO-E vs. PL) (F1,15 = 0.43, p = 0.52, η = 0.03) and conditions × time interaction (F1,15 = 3.57, p = 0.078, η = 0.19). Fluid loss was not significantly different between conditions (p = 0.08, d = 0.47). The blood glucose level was higher (p < 0.01) after exercise in CHO-E, whereas the blood lactate level was similar between conditions. In conclusion, the CHO-E solution was as effective as the artificially sweetened water in terms of fluid balance and fencing performance at a thermoneutral environment. Because of large individual variability, fencers should monitor their fluid intake and body fluid loss in training and competition.

Effects of detraining in age-group swimmers performance, energetics and kinematics.

Changes in performance, energetics and kinematics during age-group swimmers off-season inform the prescription of training for the following season. Age-group swimmers (n = 15, age 14.3 ± 0.7 years) of equal maturational stage performed a 400-m front crawl (T400) before and after a four-weeks training cessation period. Performance-related energetic and kinematic variables were obtained controlling for anthropometric changes and non-swimming specific physical activities during off-season. T400 time decreased 3.8% (95%CI 1.4 to 6.1%; p < 0.01; d = 0.90) with non-specific physical activities (1814 ± 1989 MET-min·wk-1) accounting for ~40% of the underlying variance (p = 0.01; η2 = 0.40). Stroke rate and stroke index decreased despite similar stroke length and index of coordination values. Although mean response time, amplitude, maximal oxygen uptake, heart rate, total energy expenditure, metabolic power and energy cost were similar, aerobic contribution decreased by ~1.8% (-2.7 to -0.9%; p < 0.01; d = -1.19) and anaerobic lactic contribution increased by ~1.6% (0.8 to 2.5%; p < 0.01; d = 1.08) over the off-season. Impaired performance was mainly associated with a decreased stroke rate (r = -0.85 to -0.61; p ≤ 0.02), increased peak blood lactate (r = -0.52; p = 0.05) and fewer non-swimming specific physical activities performed during the off-season (r = -0.58; p = 0.03). The end-of-season cessation of training yielded moderate impairments in age-group swimmers performance-related energetic and kinematic factors, however non-specific physical activities can minimise fitness losses.

Physiological and Tactical On-court Demands of Water Polo.

Botonis, PG, Toubekis, AG, and Platanou, TI. Physiological and tactical on-court demands of water polo. J Strength Cond Res 33(11): 3188-3199, 2019-The purpose of the present review is to provide a quantification of the specific game's activities performed by elite water polo players and a comprehensive overview of the physiological requirements reflecting physical and tactical on-court demands in water polo. Game analysis demonstrates that various swimming movements occur throughout a match play, although approximately 50% of these are recorded in horizontal body position. The various offensive and defensive tactical actions transiently modify the playing intensity, which overall corresponds to the players' lactate threshold. Even play corresponds to 60% of total game actions, whereas the respective percentage of power-play and counterattacks may exceed 30%. The ability to perform high-intensity activities with short recovery periods is critical for water polo players. Elite water polo players present a high level of aerobic power and endurance as indicated by their maximal oxygen uptake and speed at the lactate threshold. Depending on the positional roles, outfield players are characterized as centers or peripherals. The overall physiological load seems to be similar between players at various positions, despite that centers execute more dynamic body contacts, whereas peripherals more swimming bouts. Despite limitations concerning the experimental setting, the current findings indicate that the incidence of fatigue deteriorates playing intensity and performance. Nonetheless, data from the reviewed studies should be cautiously interpreted because in some of the studies, players' substitutions were not allowed. A high conditioning level is essential for water polo, as it is associated with superior technical and tactical efficacy and lower decline of physical or technical performance within the game.

Reliability and Validity of Tethered Swimming Lactate Minimum Test and Their Relationship With Performance in Young Swimmers.

PURPOSE: To test the reliability and validity of tethered swimming lactate minimum test in young swimmers. METHODS: Lactate minimum test was performed twice to test the reliability (experiment 1; n = 13). In addition, the validity was investigated through lactate minimum test relationships with tethered swimming lactate threshold and peak force obtained during graded exercise test (experiment 2; n = 11). Finally, the correlations with mean speeds observed during 200-m (s200m) and 30-minute continuous efforts (s30min) were also analyzed (experiment 3; n = 15). In all experiments, the lactate minimum test began with 3-minute all-out effort to induce lactatemia, followed by an exhaustive graded exercise test. RESULTS: The lactate minimum intensity and mean force during the entire 3-minute all-out effort (MF) showed high reliability (coefficient of variation < 8.9% and intraclass correlation coefficient > .93). The lactate minimum intensity was not different compared with lactate threshold (P = .22), presenting high correlations (r = .92) and agreement (95% limits of agreement = ±7.9 N). The mean force during the entire 3-minute all-out effort was similar to peak force obtained during graded exercise test (P = .41), presenting significant correlations (r = .88) and high indices of agreement (95% limits of agreement = ±11.3 N). In addition, lactate minimum test parameters correlated both with mean speeds observed during 200-m (r > .74) and 30-minute continuous efforts (r > .70). CONCLUSION: Thus, tethered swimming lactate minimum test can be used for training recommendations and to monitor aerobic adaptations in young swimmers.

Flexibility training in preadolescent female athletes: Acute and long-term effects of intermittent and continuous static stretching.

This study compared the acute and long-term effects of intermittent and continuous static stretching training on straight leg raise range of motion (ROM). Seventy-seven preadolescent female gymnasts were divided into a stretching (n = 57), and a control group (n = 20). The stretching group performed static stretching of the hip extensors of both legs, three times per week for 15 weeks. One leg performed intermittent (3 × 30 s with 30 s rest) while the other leg performed continuous stretching (90 s). ROM pre- and post-stretching was measured at baseline, on weeks 3, 6, 9, 12, 15 and after 2 weeks of detraining. ROM was increased during both intermittent and continuous stretching training, but remained unchanged in the control group. Intermittent stretching conferred a larger improvement in ROM compared to both continuous stretching and control from week 3, until the end of training, and following detraining (p = 0.045 to 0.001 and d = 0.80 to 1.41). During detraining, ROM after the intermittent protocol decreased (p = 0.001), while it was maintained after the continuous protocol (p = 0.36). Acute increases in ROM following the intermittent stretching were also larger than in the continuous (p = 0.038). Intermittent stretching was more effective than continuous, for both long-term and acute ROM enhancement in preadolescent female athletes.

The Effects of Recovery Duration During High-Intensity Interval Exercise on Time Spent at High Rates of Oxygen Consumption, Oxygen Kinetics, and Blood Lactate.

Smilios, I, Myrkos, A, Zafeiridis, A, Toubekis, A, Spassis, A, and Tokmakidis, SP. The effects of recovery duration during high-intensity interval exercise on time spent at high rates of oxygen consumption, oxygen kinetics, and blood lactate. J Strength Cond Res 32(8): 2183-2189, 2018-The recovery duration and the work-to-recovery ratio are important aspects to consider when designing a high-intensity aerobic interval exercise (HIIE). This study examined the effects of recovery duration on total exercise time performed above 80, 90, and 95% of maximum oxygen consumption (V[Combining Dot Above]O2max) and heart rate (HRmax) during a single-bout HIIE. We also evaluated the effects on V[Combining Dot Above]O2 and HR kinetics, blood lactate concentration, and rating of perceived exertion (RPE). Eleven moderately trained men (22.1 ± 1 year) executed, on 3 separate sessions, 4 × 4-minute runs at 90% of maximal aerobic velocity (MAV) with 2, 3, and 4 minutes of active recovery. Recovery duration did not affect the percentage of V[Combining Dot Above]O2max attained and the total exercise time above 80, 90, and 95% of V[Combining Dot Above]O2max. Exercise time above 80 and 90% of HRmax was longer with 2 and 3 minutes (p ≤ 0.05) as compared with the 4-minute recovery. Oxygen uptake and HR amplitude were lower, mean response time slower (p ≤ 0.05), and blood lactate and RPE higher with 2 minutes compared with 4-minute recovery (p ≤ 0.05). In conclusion, aerobic metabolism attains its upper functional limits with either 2, or 3 or 4 minutes of recovery during the 4 × 4-minute HIIE; thus, all rest durations could be used for the enhancement of aerobic capacity in sports, fitness, and clinical settings. The short (2 minutes) compared with longer (4 minutes) recovery, however, evokes greater cardiovascular and metabolic stress and activates to a greater extent anaerobic glycolysis and hence, could be used by athletes to induce greater overall physiological challenge.

Severe hypoxemia induced by prolonged expiration and reduced frequency breathing during submaximal swimming.

The purpose of this study was to examine the metabolic responses during submaximal swimming with self-selected normal breathing (N) and prolonged expiration along with reduced frequency breathing (RB). Ten male swimmers (age: 23.1 ± 2.2 years; VO2max: 47.3 ± 7.2 ml · kg-1 · min-1) performed 75-, 100-, 175-, 200-, 275-, 300-, 375- and 400-m trials with N and RB at intensity corresponding to 90% of the critical speed. In RB condition, all trials longer than 75 m were interspersed with 25 m of self-selected N in regular intervals. In RB, oxygen saturation during recovery was decreased compared to starting values after 75, 100, 175, 275 and 375 m (78-91%, P < 0.05), while it remained unchanged after all trials in N condition (98 ± 2%, P > 0.05). Lactate concentration was higher in RB than in N after 400 m (4.3 ± 1.5 vs. 3.3 ± 1.7 mmol · l-1, P < 0.05). During recovery after the 375-m trial, partial pressure of carbon dioxide was increased and pH was decreased in RB compared to N condition. Prolonged expiration along with RB provokes severe hypoxemia during the recovery period after swimming, which is restored with self-selected N during submaximal swimming.

Concurrent Strength and Interval Endurance Training in Elite Water Polo Players.

This study compared the effects of different high-intensity interval training (HIIT) intervals performed concurrently with strength and specific water polo training on performance indices of elite players. During the precompetition season, 2 water polo clubs were assigned to either HIIT of 4 × 4 minutes (n = 7, HIIT4 × 4) or HIIT of 16 × 100-m swimming efforts (n = 7, HIIT16 × 100). Both clubs applied the swimming (6% above the speed corresponding to blood lactate concentration of 4.0 mmol · L) and strength training (85-90% of 1 repetition maximum, 5 repetitions, 4 sets) twice per week concurrently with specific water polo training. Before and after the 8-week intervention period, maximal bench press strength was measured and a speed-lactate test (5 × 200 m) was performed to determine the speed corresponding to lactate concentration of 4.0, 5.0, and 10.0 mmol · L(-1). Maximal strength was improved in both groups (HIIT4 × 4: 14 ± 4% vs. HIIT16 × 100: 19 ± 10%). Improvements in speed corresponding to 4.0, 5.0, and 10.0 mmol · L(-1) were shown only after HIIT4 × 4 (9 ± 5, 8 ± 3, 7 ± 2%, respectively; p < 0.01). However, HIIT16 × 100 was more effective in the differential velocity between 10.0 and 5.0 mmol · L(-) development (19 ± 20%, p = 0.03). During the precompetition season, HIIT and strength training together with specific water polo training performed concurrently improves muscle strength and allows specific adaptations enhancing swimming performance of elite water polo players.

Performance Decrement and Skill Deterioration During a Water Polo Game are Linked With the Conditioning Level of the Athletes.

The aim of the study was to examine whether physical and technical performance deterioration after a water polo game is related to the athletes' conditioning level. Blood lactate concentration was measured during a 5 × 200-m incremental swimming test in 10 male water polo athletes to calculate the velocities corresponding to 4.0, 5.0, and 10.0 mmol·L lactate concentration (V4, V5, and V10, respectively) and define their conditioning level. All athletes participated in 5 competitive water polo games. Before (Pre), at half time (Mid), and after (Post) the first 2 games, handgrip strength and repeated sprint ability (8 × 20-m) were measured. Pre and Post the next 2 games, ball throwing velocity, shooting accuracy, and 400-m swim were evaluated. Pre, Mid, and Post the last game, the eggbeater kick test was performed. Handgrip strength, repeated sprint ability, 400-m swim performance, and ball shooting accuracy decreased after the game (8.4 ± 6.2%, 6.3 ± 3.4%, 7.0 ± 4.1%, and 20.3 ± 23.4%, respectively, p ≤ 0.05). V4, V5, and V10 were not significantly correlated with changes in physical or technical performance after the game. Performance in 400-m swim correlated with V4 and V5 whereas changes in 400-m swim Pre-Post, correlated with changes in ball shooting accuracy and throwing velocity (r = 0.73 and r = 0.80, p ≤ 0.05). These data suggest that V4, V5, and V10 may not correlate with performance decline in water polo. Interestingly, the 400-m swim test is connected with the decline in repeated sprints, ball shooting accuracy, and throwing velocity after a water polo game in well-trained athletes.

Effects of Short-Interval and Long-Interval Swimming Protocols on Performance, Aerobic Adaptations, and Technical Parameters: A Training Study.

Dalamitros, AA, Zafeiridis, AS, Toubekis, AG, Tsalis, GA, Pelarigo, JG, Manou, V, and Kellis, S. Effects of short-interval and long-interval swimming protocols on performance, aerobic adaptations, and technical parameters: A training study. J Strength Cond Res 30(10): 2871-2879, 2016-This study compared 2-interval swimming training programs of different work interval durations, matched for total distance and exercise intensity, on swimming performance, aerobic adaptations, and technical parameters. Twenty-four former swimmers were equally divided to short-interval training group (INT50, 12-16 × 50 m with 15 seconds rest), long-interval training group (INT100, 6-8 × 100 m with 30 seconds rest), and a control group (CON). The 2 experimental groups followed the specified swimming training program for 8 weeks. Before and after training, swimming performance, technical parameters, and indices of aerobic adaptations were assessed. ΙΝΤ50 and ΙΝΤ100 improved swimming performance in 100 and 400-m tests and the maximal aerobic speed (p ≤ 0.05); the performance in the 50-m swim did not change. Posttraining V[Combining Dot Above]O2max values were higher compared with pretraining values in both training groups (p ≤ 0.05), whereas peak aerobic power output increased only in INT100 (p ≤ 0.05). The 1-minute heart rate and blood lactate recovery values decreased after training in both groups (p < 0.01). Stroke length increased in 100 and 400-m swimming tests after training in both groups (p ≤ 0.05); no changes were observed in stroke rate after training. Comparisons between groups on posttraining mean values, after adjusting for pretraining values, revealed no significant differences between ΙΝΤ50 and ΙΝΤ100 for all variables; however, all measures were improved vs. the respective values in the CON (p < 0.001-0.05). In conclusion, when matched for distance and exercise intensity, the short-interval (50 m) and long-interval (100 m) protocols confer analogous improvements in swimming performance, in stroke cycle parameters, and in indices of aerobic adaptations after 8 weeks of training.

Aerobic, resistance and combined training and detraining on body composition, muscle strength, lipid profile and inflammation in coronary artery disease patients.

Fifty-six elderly individuals diagnosed with coronary artery disease participated in the study and were divided into four groups: an aerobic exercise group, a resistance exercise group, a combined (aerobic + resistance) exercise group and a control group. The three exercise groups participated in 8 months of exercise training. Before, at 4 and at 8 months of the training period as well as at 1, 2 and 3 months after training cessation, muscle strength was measured and blood samples were collected. The resistance exercise caused significant increases mainly in muscle strength whereas aerobic exercise caused favourable effects mostly on lipid and apolipoprotein profiles. On the other hand, combined exercise caused significant favourable effects on both physiological (i.e. muscle strength) and biochemical (i.e. lipid and apolipoprotein profile and inflammation status) parameters, while the return to baseline values during the detraining period was slower compared to the other exercise modalities.

The influence of the hand's acceleration and the relative contribution of drag and lift forces in front crawl swimming.

The aim of this study was to assess the effect of the hand's acceleration on the propulsive forces and the relative contribution of the drag and lift on their resultant force in the separate phases of the front crawl underwater arm stroke. Ten female swimmers swam one trial of all-out 25-m front crawl. The underwater motion of each swimmer's right hand was recorded using four camcorders and four periscope systems. Anatomical landmarks were digitised, and the propulsive forces generated by the swimmer's hand were estimated from the kinematic data in conjunction with hydrodynamic coefficients. When the hand's acceleration was taken into account, the magnitude of the propulsive forces was greater, with the exception of the mean drag force during the final part of the underwater arm stroke. The mean drag force was greater than the mean lift force in the middle part, while the mean lift force was greater than the mean drag force in the final part of the underwater arm stroke. Thus, swimmers should accelerate their hands from the beginning of their backward motion, press the water with large pitch angles during the middle part and sweep with small pitch angles during the final part of their underwater arm stroke.

Is Speed Reserve Related to Critical Speed and Anaerobic Distance Capacity in Swimming?

This study examines the relationship between speed reserve (SRes), critical swimming speed (CSS), and anaerobic distance capacity (ADC) and their efficacy in determining training adaptations. Swimmers with previous competitive experience participated in an 8-week aerobic training program (experimental group: E; n = 15, age: 22.29 ± 0.95 years) and a control group refrained from training during the same period (C; n = 6, age: 22.25 ± 2.22 years). Speed reserve was determined before and after training from the speed difference between the 50 and 400 m maximum tests. Both CSS and ADC were calculated using 2 different combinations of distances (50 and 400 m: CSS2/ADC2; 50, 100, and 400 m: CSS3/ADC3) by applying the distance-time linear regression model. CSS2 and CSS3 of the E group showed a negative correlation, whereas ADC2 and ADC3 showed a positive correlation, with SRes before and after the training period (r ≥ -0.66, r ≥ 0.88, p ≤ 0.05). CSS2 and CSS3 increased by 5.5 ± 3.2 and 6.0 ± 3.2%, whereas ADC2, ADC3, and SRes decreased by 12.0 ± 9.4, 9.0 ± 11.2, and 8.1 ± 8.4% with the training program (p ≤ 0.05). These findings suggest that SRes, as calculated from distances of 50 and 400 m, shows strong relationships with CSS and ADC and may be used as an indicator of training-induced changes. This information is expected to facilitate training control and evaluation in a day-to-day basis.