Match Running Performance Profile and Heart Rate Response in Amputee Soccer Players.

INTRODUCTION: The purpose of this study was (a) to create a profile of the running performances of male amputee soccer players in different speed zones, (b) to investigate the relationship between heart rate (HR) and running distance in two soccer matches, and (c) to study the effect of the level of amputation on the running distance covered during a match. MATERIAL AND METHODS: The participants were male amputee soccer players (n = 10, Greek, n = 5; Belgian, n = 5) who played two international, friendly matches. Distances were measured using a global positioning system, and HRs were recorded using a Polar Team Pro. RESULTS: No differences in the distances covered were observed between participants with different levels of amputation (p > 0.05). Nevertheless, there was a trend that participants with a below-the-knee amputation tended to cover longer distances in total (difference +262.3 m, Cohen's d = 0.40) and in zones 2 (+324.4 m, d = 0.79), 3 (+ 7.1 m, d = 0.65), 4 (+22.7 m, d = 0.43), and 5 (+0.4 m, d = 0.20) and less distance in zone 1 (-207.2 m, d = 0.88). They also tended to perform more accelerations (+3.9, d = 0.89) and decelerations (+4.2, d = 0.87) and had a higher mean HR (+8.4%, d = 2.04) than those with an above-the-knee amputation. Moreover, the mean HR corresponded to 83.3% of the HRmax and did not correlate with distance in any speed zone. CONCLUSIONS: It was concluded that the level of amputation might influence running performance and acute physiological response during a soccer match.

Construct validity of gymnastics-specific assessment on the neuromuscular function of shoulder flexor and extensor muscles.

The present study examined the construct validity of gymnastics-specific measurements of the shoulder flexor and extensor neuromuscular function. Fifteen male gymnasts and 18 male physical education (PE) students participated voluntarily. The electromyogram (EMG) of 3 flexor and 3 extensor shoulder muscles was assessed during isometric (45, 90, and 135º) and isokinetic (concentric and eccentric 60, 180, and 300º/s) shoulder flexion/extension. Peak torque (PT) and neuromuscular function in terms of neuromuscular efficiency (NME, i.e. torque to EMG ratio) and antagonist/agonist coactivation index were evaluated. The construct validity of the measurements was supported by the ability to discriminate between gymnasts and physical education (PE) students, taking into consideration the shoulders' neuromuscular function parameters (37%-57% of the variability explained). After accounting for the limitations of the study, these findings may assist gymnastics coaches and researchers to develop and evaluate more effective training methods for athletes related to shoulder joint physiological characteristics and level of expertise.

Repeated sprint ability in young football players according to the position and formation of the team: the effect of a specific training program.

BACKGROUND: The aim of this study was to investigate the effect of a specific training program for 12-weeks (twice a week) on the repeated sprint ability (RSA), according to the position of the football player in the formation of the team. METHODS: Two groups of U-17 football players (experimental-group, N.=22 and control-group, N.=19) and five positions (central-defenders, wide-defenders, central-midfielders, wingers, and central-attackers) according to the position in the formation (1-4-3-3) were studied. Sexual maturation was classified according to Tanner's stages. RSA and isokinetic strength were measured pre- and after the training program. RESULTS: The results showed that in RSA were differences in the factor time in the best (F=9.316, η2=0.383, P=0.008) and mean time (F=8.002, η2=0.348, P=0.013), but there were no differences between the groups. In strength, differences were observed in the time, mostly in the extensors at the three angular velocities (60°, 180°, 300°·sec-1) with differences in the group only in the maximum force (F=8.090, η2=0.366, P=0.013). No differences between players' positions were observed. CONCLUSIONS: A specific training program seems to affect players' performance on repeated sprint ability and the specific training in the players' position according to the team formation has a positive effect on the muscle power of football players.

Surface Electromyographic Activity of the Rectus Abdominis and External Oblique during Isometric and Dynamic Exercises.

Exercises for the abdominal muscles are widely used in athletic activities for strength training and prevention of low back disorders. The timing and volume of muscle activation for various movements have not yet been clarified. The purpose of this research was to evaluate the surface electromyographic activity from the upper (RAU) and lower part (RAL) of the rectus abdominis and the external oblique (EO) muscles during eleven abdominal muscle strength training exercises. Thirty-five healthy male university students with a subspecialty in soccer participated in the study. They performed exercises involving isometric, concentric, and eccentric muscle contractions. The electromyographic recordings were amplified by a factor of 1000, rectified, and integrated. Mean integrated values were calculated by dividing the elapsed time for the five repetitions, to provide the mean integrated electromyographic values for each exercise. Leg movements from a long lying position showed higher activity of the rectus abdominis, compared to the EO (p < 0.001). The dynamic sit-ups showed an obvious dominant activity of the EO, compared to the rectus abdominis (p < 0.001). During eccentric exercise, higher activity was found in the RAU, compared to the RAL (p < 0.001). The results could serve as a basis for improving the design and specification of training exercises. Pre-exercises should be performed before testing abdominal muscle strength.

A Novel mHealth Monitoring System during Cycling in Elite Athletes.

BACKGROUND: Cycling is a very demanding physical activity that may create various health disorders during an athlete's career. Recently, smart mobile and wearable technologies have been used to monitor physiological responses and possible disturbances during physical activity. Thus, the application of mHealth methods in sports poses a challenge today. This study used a novel mobile-Health method to monitor athletes' physiological responses and to detect health disorders early during cycling in elite athletes. METHODS: Sixteen high-level cyclists participated in this study, which included a series of measurements in the laboratory; health and performance assessments; and then application in the field of mHealth monitoring in two training seasons, at the beginning of their training period and in the race season. A field monitoring test took place during 30 min of uphill cycling with the participant's heart rate at the ventilatory threshold. During monitoring periods, heart rate, oxygen saturation, respiratory rate, and electrocardiogram were monitored via the mHealth system. Moreover, the SpO2 was estimated continuously, and the symptoms during effort were reported. RESULTS: A significant correlation was found between the symptoms reported by the athletes in the two field tests and the findings recorded with the application of the mHealth monitoring method. However, from the pre-participation screening in the laboratory and from the spiroergometric tests, no abnormal findings were detected that were to blame for the appearance of the symptoms. CONCLUSIONS: The application of mHealth monitoring during competitive cycling is a very useful method for the early recording of cardiac and other health disorders of athletes, whose untimely evaluation could lead to unforeseen events.

Effects of soccer training in muscular strength: a comparative study in trained youth soccer players and untrained boys of the same biological age.

BACKGROUND: It is not clear if soccer training affected the development of muscle strength positively in children. We hypothesize that soccer training could positively affect the isokinetic concentric muscle strength and anthropometric characteristics in different ages of adolescents of the same biological age. METHODS: A total of 126 young soccer players (N.=66) and untrained boys (N.=60) throughout the developmental ages of 12, 14 and 16 years volunteered to participate in the study. Sexual maturation was classified according to Tanner's stages. Soccer players, except from their school's physical education program, participate also in a soccer training program. All participants underwent anthropometric measurements. The isokinetic-concentric peak torque values of the hamstrings (H) and quadriceps (Q), as well as the conventional strength ratios of H:Q, were measured on an isokinetic dynamometer at angular velocities of 60, 180, and 300°·s-1. RESULTS: Anthropometric differences in the same age group, between trained and untrained, were presented only for 12-year-olds (height, P<0.001 and BMI, P<0.01). Between groups, differences were observed in almost all anthropometric measurements, probably as result of development. The absolute isokinetic-concentric muscle strength was significantly higher (P<0.001) in the 12- and 16-year-old trained group, compared to untrained, for the knee-flexors and knee-extensors. However, no significant differences were found between the trained and untrained 14-year-olds, for the muscle groups of Q and H. The H:Q strength ratios did not differ between groups at all angular velocities. CONCLUSIONS: The results of this study showed that systematic soccer training has a positive effect in the peripheral system, expressed as an increased lower limb muscle strength; specifically, Q and H.

The effects of soccer training in aerobic capacity between trained and untrained adolescent boys of the same biological age.

BACKROUND: The purpose of this study was to examine the effects of soccer training on maximal oxygen uptake and anthropometric characteristics in different ages of soccer players and untrained adolescents of the same biological age. METHODS: A total of one hundred and twenty-six (N.=126) young soccer players and untrained boys throughout the developmental ages of 12 (soccer players N.=22; untrained boys = 22) 14 (soccer players N.=20; untrained boys = 18) and 16 (soccer players N.=22; untrained boys = 22) volunteered to participate in the study. Sexual maturation was classified according to Tanner's stages. Soccer players participated both in their school's physical education program and in a soccer training program, while the untrained participated only in their school's physical education program. All participants underwent anthropometric measurements and performed a maximal exercise test on a motor driven treadmill to determine maximal oxygen uptake (V̇O2max) and cardiorespiratory indices. Blood lactate (BL) concentration was determined in the 5th minute of recovery using a lactate photometer. RESULTS: The trained group showed significantly higher V̇O2max, in absolute and relative values (P<0.001), BLmax (P<0.05) and maximal respiratory exchange ratio (RERmax) (P<0.05) compared to the untrained group. Resting heart rate (HR) and systolic blood pressure were significantly lower (P<0.05) for the trained compared to untrained. CONCLUSIONS: The results of this study showed that systematic soccer training has a positive effect in the central cardiovascular system expressed as V̇O2max, HR and blood pressure.

Myosin heavy chain isoform composition in the deltoid and vastus lateralis muscles of elite handball players.

The purpose of the present study was to compare the myosin heavy chain (MHC) isoform composition of the deltoid and vastus lateralis muscles of the dominant and non-dominant limbs in handball players. Eleven male Greek elite handball players (age 22.6 ± 1.9 yrs, training experience 10.6 ± 2.1 yrs, height 184.1 ± 4.1 cm, and weight 81.0 ± 12.5 kg) participated in the study. Four muscle biopsies were obtained from the dominant and non-dominant deltoid and vastus lateralis muscles during the in-season period. The MHC composition was determined using SDS-PAGE. No significant difference was found between the dominant and non-dominant muscles; Deltoid muscle: MHC I [(95%CI = -1.22, 0.33), P = 0.228], MHC ΙΙa [(95%CI = -0.32, 1.59), P = 0.168] and MHC IIx [(95%CI = -1.49, 1.10), P = 0.749]; Vastus lateralis muscle: MHC I [(95%CI = -0.38, 0.63), P = 0.586], MHC ΙΙa [(95%CI = -0.50, 0.65), P = 0.783] and MHC IIx [(95%CI = -1.08, 0.42), P = 0.355]. The findings of the present study indicate that the greater use of the dominant limbs for throwing actions and body movements in handball do not lead to altered MHC isoform composition compared to the non-dominant limbs.

Effects of Exercise and an Integrated Neuromuscular Inhibition Technique Program in the Management of Chronic Mechanical Neck Pain: A Randomized Controlled Trial.

OBJECTIVE: The aim of this study was to evaluate the effect of adding the integrated neuromuscular inhibition technique (INIT) to therapeutic exercise (TE) in individuals with chronic mechanical neck pain (CMNP). METHODS: In this 34-week, assessor-blind randomized controlled trial, 40 participants (men and women) with CMNP with active or latent myofascial trigger points on the neck muscles were divided into 2 groups. The participants followed 4 treatments per week for 10 weeks. The intervention group followed a TE program in combination with the INIT, whereas the control group followed the same program without the INIT. Both protocols were applied by physiotherapists. Pain, disability, pressure pain threshold, active range of motion, and health-related quality of life were evaluated before, during, and after the intervention, whereas patients were followed for 6 months after completion of treatment. Repeated-measures ANOVA was applied. RESULTS: Both groups showed a significant improvement in all dependent measures after the intervention (P < .05). However, the intervention group showed greater improvement in the visual analog scale and neck disability index score, in the neck muscles pressure pain threshold, in the range of motion, and in the 36-Item Short Form Health Survey score, than the control group. In many of the above variables this improvement was seen from the second week and was maintained for 6 months after the intervention. CONCLUSION: The results of this preliminary study suggest that the addition of the INIT to a TE program had a positive effect on pain, functionality, and the quality of life in individuals with CMNP.

Muscle-tendon morphology and function following long-term exposure to repeated and strenuous mechanical loading.

We mapped structural and functional characteristics of muscle-tendon units in a population exposed to very long-term routine overloading. Twenty-eight military academy cadets (age = 21.00 ± 1.1 years; height = 176.1 ± 4.8 cm; mass = 73.8 ± 7.0 kg) exposed for over 24 months to repetitive overloading were profiled via ultrasonography with a senior subgroup of them (n = 11; age = 21.4 ± 1.0 years; height = 176.5 ± 4.8 cm; mass = 71.4 ± 6.6 kg) also tested while walking and marching on a treadmill. A group of eleven ethnicity- and age-matched civilians (age = 21.6 ± 0.7 years; height = 176.8 ± 4.3 cm; mass = 74.6 ± 5.6 kg) was also profiled and tested. Cadets and civilians exhibited similar morphology (muscle and tendon thickness and cross-sectional area, pennation angle, fascicle length) in 26 out of 29 sites including the Achilles tendon. However, patellar tendon thickness along the entire tendon was greater (P < .05) by a mean of 16% for the senior cadets compared with civilians. Dynamically, cadets showed significantly smaller ranges of fascicle length change and lower shortening velocity in medial gastrocnemius during walking (44.0% and 47.6%, P < .05-.01) and marching (27.5% and 34.3%, P < .05-.01) than civilians. Furthermore, cadets showed lower normalized soleus electrical activity during walking (22.7%, P < .05) and marching (27.0%, P < .05). Therefore, 24-36 months of continuous overloading, primarily occurring under aerobic conditions, leads to more efficient neural and mechanical behavior in the triceps surae complex, without any major macroscopic alterations in key anatomical structures.

Effects of an integrated neuromuscular inhibition technique program on neck muscle strength and endurance in individuals with chronic mechanical neck pain.

BACKGROUND: The aim of this study was to investigate whether the application of the integrated neuromuscular inhibition technique (INIT) combined with therapeutic exercise (TE) can provide faster and greater improvement in maximum isometric strength and isometric endurance of the neck muscles in patients with chronic mechanical neck pain (CMNP). METHODS: In this 10-week, single-blind clinical trial, 40 participants (men and women) with CMNP were divided into two groups. The intervention group (IG) followed a TE program in combination with the INIT, while the control group (CG) followed the same TE program without the INIT technique. Changes in maximum isometric strength and isometric endurance of the neck muscles were evaluated before, during, and after the intervention, with follow-up measurements taken at 1, 3, and 6 months after the intervention. Analysis of variance with repeated measures was applied. RESULTS: Both groups showed a significant improvement in all dependent measures after the intervention (p < .05). These changes were maintained for both groups 6 months after the intervention. However, the IG showed a greater improvement in the maximum isometric strength of neck flexion and an improved craniocervical flexion test score compared with the CG. CONCLUSION: The combination of TE and INIT had a positive effect on neck muscle strength and endurance in individuals suffering from CMNP as compared with TE alone.

Correlation of Fiber-Type Composition and Sprint Performance in Youth Soccer Players.

Metaxas, T, Mandroukas, A, Michailidis, Y, Koutlianos, N, Christoulas, K, and Ekblom, B. Correlation of fiber-type composition and sprint performance in youth soccer players. J Strength Cond Res 33(10): 2629-2634, 2019-The aim of this study was to examine the correlation between muscle fiber type and sprint performance in elite young soccer players of different age groups of the same team. Twenty-eight young players participated in this study (group U15, n = 8; group U13, n = 9; and group U11, n = 11). Anthropometric assessments, acceleration (10 m), and Bangsbo modified sprint test (30 m) were performed. Muscle biopsies were obtained from the vastus lateralis, and after that, fiber-type composition was determined by immunohistochemistry. No significant correlations were found between the sprint test and muscle fiber distribution for the groups U13 and U11 (p > 0.05). Also, no correlations were found between cross-sectional areas in the types of fibers with the sprint test in all groups (p > 0.05). A positive correlation was found between type I fibers and the performance in the acceleration test (10 m) (r = 0.77, p < 0.05) was found only in group U15 and a negative correlation between type IIA fibers and the performance in the acceleration test (10 m) (r = -0.89, p < 0.05). The correlations were observed only in group U15, which may indicate that the duration and the intensity of the soccer systematic training can affect the plasticity of the muscle fibers. Specific soccer training in youth is one of the factors that can affect fiber-type plasticity. The specific training programs and status of U15 are more intensive, and the exercises are oriented more to improve physical fitness.

Inspiratory muscle training effects on oxygen saturation and performance in hypoxemic rowers: Effect of sex.

Exercise-induced arterial hypoxemia (EIAH) has been consistently reported in elite endurance athletes. This study examined the effects of an inspiratory muscle training protocol (IMT) on resting pulmonary function, end-exercise arterial oxygen saturation and performance in hypoxemic rowers. Twenty male and sixteen female well-trained hypoxemic rowers were divided into four groups: IMT-male, control-male, IMT-female and control-female. The IMT groups, additionally to the regular training, performed IMT (30 min/day, 5 times/week, 6 weeks). Before and after training, groups underwent an incremental rowing test, a 2000-m time trial and a 5-min "all-out" race. IMT increased respiratory strength in the IMT-male (135 ± 31 vs. 180 ± 22 cmH2O) and IMT-female (93 ± 19 vs. 142 ± 22 cmH2O) (P < 0.05). The IMT-female group exhibited lower EIAH and improved rowing performance in the 2000-m time trial (487 ± 32 vs. 461 ± 34 sec) and in the 5-min "all-out" test (1,285 ± 28 vs. 1,310 ± 36m) (P < 0.05). IMT protocol improved performance in IMT-male only in the 5-min test (1,651 ± 31 vs. 1,746 ± 37m) (P < 0.05). IMT may be a useful tool for increasing respiratory strength and enhancing performance in hypoxemic rowers, especially for women. Abbreviations: EIAH: Exercise-induced arterial hypoxemia; IMT: inspiratory muscle training protocol; PaO2: partial pressure of arterial oxygen; SaO2: arterial oxyhemoglobin saturation; VO2max: maximal oxygen consumption; [(A-a)DO2]: alveolar-to-arterial oxygen difference; VA/Q: ventilation-perfusion inequality/mismatching; PImax: maximal inspiratory pressure; BMI: body mass index; BSA: body surface area; FVC: vital capacity; FEV1: forced expiratory volume in 1 sec; VCin: vital capacity; MVV12: maximal voluntary ventilation in 12 sec.

Effects of sprint interval exercise dose and sex on circulating irisin and redox status markers in adolescent swimmers.

Irisin and redox status markers seem to share common pathways of exercise-induced upregulation. The aim of the present study was to assess the effects of sprint interval swimming exercise dose and sex on the circulating levels of irisin and redox status markers in adolescent swimmers. Sixteen male and 16 female adolescent swimmers completed two sets of 4 × 50 m maximal freestyle swimming with a send-off time of 90 s, separated by 10 min of passive recovery. Venous blood samples were obtained pre-exercise (Pre), after the first set (Post1) and after the second set (Post2). Males had higher irisin levels than females. Reduced glutathione (GSH, µmol g Hb-1) increased from 8.6 (2.2) [pooled males and females, mean (SD) throughout] at Pre to 9.4 (2.1) at Post1 and Post2. Total antioxidant capacity (µmol DPPH mL-1) increased from 0.89 (0.17) at Post1 to 0.94 (0.16) at Post2. 8-hydroxy-2´-deoxyguanosine (ng mL-1) increased from 20.9 (6.9) at Pre and 21.5 (7.1) at Post1 to 25.0 (10.9) at Post2. Overall, sprint interval swimming exercise induced small but potentially effective changes in the studied parameters. Exercise dose influenced the GSH and 8-OHdG responses, and sex affected irisin levels.

Fitness effects of one-year soccer training of 8-10 and 10-12-year-old school children.

BACKGROUND: The purpose of the study was to investigate the effect of one-year soccer training on physical fitness performance, of under ten (U10) and under twelve (U12) youth levels. METHODS: The study included 28, 10-year-old children, and 28, 12-year-old children. In the U12 group, 19 children participated only in the physical fitness sessions at school (control group) and 9 children in four extra soccer trainings (soccer group). In the U10 group, 11 children participated only in the physical fitness sessions at school (control group) and 17 children in four extra soccer trainings (soccer group). Height, body weight, body fat, standing long jump, 30 m sprint, sit and reach test, abdominal test and Yo-Yo IE1 tests were performed at the beginning and at the end of the season. RESULTS: School physical education programs and soccer training cannot affect anthropometric characteristics like body fat and Body Mass Index. Soccer groups improve their performances at all fitness tests (P<0.05). The U10 control group did not increase its performance in abdominal test and the U12 level control group did not improve in the abdominal test nor Yo-Yo IE1 Test. Soccer groups in all ages indicated greater improvements than control groups (P<0.05). CONCLUSIONS: In conclusion soccer training four times per week can improve the physical fitness of U10 and U12 children.

The effect of beach volleyball training on muscle performance of indoor volleyball players.

BACKGROUND: Beach volleyball is frequently used as a conditioning activity for indoor volleyball players, but little information exists regarding any performance benefits when transitioning from sand to hard court. The present study examined the effect of 12 weeks beach volleyball training on muscle performance of indoor volleyball players. METHODS: Eleven athletes who completed an indoor volleyball season and were willing to train and compete at beach volleyball, participated in the study. Muscle endurance of knee extensors and plantar flexors (torque at 120°·s-1 following 40 contractions), muscle strength of knee extensors/ flexors (60, 180, 300°·s-1), dorsi/plantar flexors (torque at 60, 120, 180°·s-1) trunk flexors (60, 90, 180°·s-1) and power (squat [SJ] and countermovement [CMJ] jumps performed on sand and hard court surfaces) were assessed pre- and post-12 weeks of beach volleyball training. RESULTS: Knee extensors and plantar flexors endurance was higher post-12 weeks, as less torque decrease was found after 40 contractions for both muscle groups at post-12-week-time points. Knee extensors strength was higher post-12-weeks for 60 and 300°·s-1, while dorsi flexors strength was higher post-12 weeks for all speeds. SJ and CMJ vertical jump height was improved when measured on sand and on hard court. CONCLUSIONS: Twelve weeks of systematic training and competition at beach volleyball can improve muscular endurance of lower limbs and jumping height in indoor volleyball players. More importantly, these improvements are transferrable to hard court, making beach volleyball a very attractive alternative for conditioning indoor volleyball players during the off-indoor volleyball season.

Effects of Different Exercise Modes on the Urinary Metabolic Fingerprint of Men with and without Metabolic Syndrome.

Exercise is important in the prevention and treatment of the metabolic syndrome (MetS), a cluster of risk factors that raises morbidity. Metabolomics can facilitate the optimization of exercise prescription. This study aimed to investigate whether the response of the human urinary metabolic fingerprint to exercise depends on the presence of MetS or exercise mode. Twenty-three sedentary men (MetS, n = 9, and Healthy, n = 14) completed four trials: resting, high-intensity interval exercise (HIIE), continuous moderate-intensity exercise (CME), and resistance exercise (RE). Urine samples were collected pre-exercise and at 2, 4, and 24 h for targeted analysis by liquid chromatography-mass spectrometry. Time exerted the strongest differentiating effect, followed by exercise mode and health status. The greatest changes were observed in the first post-exercise samples, with a gradual return to baseline at 24 h. RE caused the greatest responses overall, followed by HIIE, while CME had minimal effect. The metabolic fingerprints of the two groups were separated at 2 h, after HIIE and RE; and at 4 h, after HIIE, with evidence of blunted response to exercise in MetS. Our findings show diverse responses of the urinary metabolic fingerprint to different exercise modes in men with and without metabolic syndrome.

Knee Muscles Isokinetic Evaluation after a Six-Month Regular Combined Swim and Dry-Land Strength Training Period in Adolescent Competitive Swimmers.

Previous studies demonstrated significant increases in the shoulder internal rotators' peak torque values and unilateral muscular imbalances of the shoulder rotators after a competitive swim period. However, there are no similar data concerning the knee muscles. The purpose of the current study was to examine the effects of a six-month training period on knee flexor and extensor peak torque values, examine a possible bilateral strength deficit and evaluate the unilateral strength balance in competitive swimmers. Eleven male adolescent swimmers (age: 14.82 ± 0.45 years) were tested for concentric knee extension and flexion peak torque (60°/s) with an isokinetic dynamometer, before and after a regular combined swim and dry-land strength training period. A trend towards greater improvements in the knee extensor compared to flexor muscles peak torque was observed. Furthermore, the bilateral strength deficit remained almost unchanged, whereas unilateral strength imbalance was increased for both limbs. However, all results were non-significant (p > 0.05). According to the data presented, a six-month regular combined swim and dry-land strength training period caused non-significant alterations for all the parameters evaluated during isokinetic testing. This study highlights the fact that competitive adolescent swimmers demonstrated unilateral knee strength imbalances throughout a long period of their yearly training macrocycle.

Cardiorespiratory and metabolic alterations during exercise and passive recovery after three modes of exercise.

The objective of this study was to investigate the potential variations in cardiorespiratory and metabolic parameters and running performance among 3 modes of exercise of the same duration, namely, intermittent running with active recovery (AR) or passive recovery (PR) and continuous running (CR) and whether these variations could affect passive recovery time (PRT). Fifteen male physical education students with a subspecialty in soccer were studied (mean age 22.3 ± 2.5 years, training experience 12.3 ± 2.5 years) in the middle of the playing season. The results showed that during exercise, the highest heart rate (HR) and VO2 values were observed in CR, whereas the lowest values in PR followed by AR. Blood lactate (BLa) concentration was higher in PR by 38% compared to that in AR (p < 0.05). The exercise duration was similar between PR and AR tests and longer than in CR. With regard to PRT, the highest HR (186 ± 9 b · min(-1)), VO2 (55.5 ± 5.2 ml · kg(-1) · min(-1)), and BLa (5.1 ± 1.7 mmol · L(-1)) values were found in CR. No differences in HR and VO2 between PR and AR were detected. However, despite the differences in BLa concentration between AR and PR during exercise, the PRT BLa values between these 2 exercise modes were not different. Among the 3 running protocols, only CR appeared to have fully challenged the cardiorespiratory system inducing maximal HR and VO2 responses during exercise and high BLa values in PRT, yet these responses were not associated with better exercise performance compared to intermittent running. Therefore, intermittent exercise, regardless of implementing passive or active interval, might be the preferable exercise mode particularly in activities extended over 30 minutes.

The effect of different exercise-testing protocols on atrial natriuretic peptide.

The aim of this study was to examine and to compare alterations in the secretion of atrial natriuretic peptide (ANP) during different exercise-testing protocols in moderately trained men. Fifteen healthy male physical education students were studied (mean age 22·3 ± 2·5 years, training experience 12·3 ± 2·5 years, height 1·80 ± 0·06 m, weight 77·4 ± 8·2 kg). Participants performed an initial graded maximal exercise testing on a treadmill for the determination of VO(2max) (duration 7·45-9·3 min and VO(2max) 55·05 ± 3·13 ml kg(-1) min(-1) ) and were examined with active recovery (AR), passive recovery (PR) and continuous running (CR) in random order. Blood samples for plasma ANP concentration were taken at rest (baseline measurement), immediately after the end of exercise as well as after 30 min in passive recovery time (PRT). The plasma ANP concentration was determined by radioimmunoassay (RIA). The results showed that ANP plasma values increased significantly from the rest period to maximal values. In the short-term graded maximal exercise testing the ANP plasma values increased by 56·2% (44·8 ± 10·4 pg ml(-1) versus 102·3 ± 31·3 pg ml(-1) , P<0.001) and in the CR testing the ANP levels increased by 29·2% (44·8 ± 10·4 pg ml(-1) versus 63·3 ± 19·8 pg ml(-1) , P<0.001) compared to the baseline measurement. Moreover, the values of ANP decreased significantly (range 46·4-51·2%, P<0.001) in PRT after the end of the four different exercise modes. However, no significant difference was evident when ANP values at rest and after AR and PR were compared. It is concluded that the exercise testing protocol may affect the plasma ANP concentrations. Particularly, short-term maximal exercise significantly increases ANP values, while the intermittent exercise form of active and passive recovery decreases ANP concentrations.