Effects of moderate- vs. high-intensity interval training on physical fitness, enjoyment, and affective valence in overweight/obese female adolescents: a pre-/post-test study.

OBJECTIVE: The aim of this study was to compare the effects of 12-week moderate-intensity interval training (MIIT) vs. high-intensity interval training (HIIT) on body composition, physical fitness, and psychological valence in overweight/obese (OW/OB) female adolescents. PATIENTS AND METHODS: Thirty-eight OW/OB female students were randomized into HIIT (n=13), MIIT (n=13) or control (n=12) groups. The participants underwent a 12-week interval-training program at 100% to 110% and 60% to 75% of maximal aerobic speed for HIIT and MIIT, respectively. The control group kept their usual physical activity without completing the training program. Pre- and post-training measurements were performed to assess body composition, aerobic capacity, and anaerobic performance (using selected tests evaluating speed, jumping ability, and strength). Ratings of perceived exertion and the feeling scale were evaluated every three weeks. Enjoyment was measured at the end of the program. A two-way analysis of variance with repeated measurements was applied to test for "group×time" interactions for body composition, physical fitness, and affective variables. RESULTS: Significant "group×time" interactions were detected for aerobic and anaerobic performance, body composition indices, and the feeling scale. HIIT resulted in more noticeable improvements in body composition and physical performance than MIIT, while no significant changes were found in the control group. Throughout the program, the feeling score has progressively increased in the MIIT group but decreased in the HIIT group. Ratings of the perceived exertion have increased in both groups, more noticeably in the HIIT group. At the end of the program, the MIIT group showed a higher enjoyment score. CONCLUSIONS: Despite offering better body composition improvement and physical fitness enhancement, HIIT offered lesser enjoyment and affective valence than MIIT in OW/OB female adolescents. MIIT might be an alternative time-efficient protocol for improving health in this population.

Skinfold thickness variation and associations with cardiorespiratory fitness in male soccer players of different ages.

OBJECTIVE: The aim of the present study was to examine skinfold thickness (SKF) distribution in youth and adult male soccer players regarding cardiorespiratory fitness (CRF) and the role of age. PATIENTS AND METHODS: Participants were youth [n=83, age 16.2 (1.0) years, mean (standard deviation)] and adult male soccer players [n=121, 23.2 (4.3) years], who were tested for SKF on 10 anatomical sites and Conconi test was used to assess velocity at maximal oxygen uptake (vVO2max). RESULTS: A between-within-subjects analysis of variance revealed a small interaction between the anatomical site and age group on SKF (p=0.006, η2=0.022), where adolescents had larger cheek (+0.7 mm; p=0.022; 95% confidence intervals - CI  - 0.1, 1.3), triceps (+0.9 mm; p=0.017; 95% CI 0.2, 1.6) and calf (+0.9 mm; p=0.014; 95% CI 0.2, 1.5) SKF, while adults had larger chin (+0.5 mm; p=0.007; 95% CI 0.1, 0.8) SKF, and no difference was observed for the rest of the anatomical sites. No difference between adolescent and adult age groups was observed in average SKF (SKFavg) [9.0 (2.7) vs. 9.1 (2.5) mm; difference -0.1 mm; 95% CI, -0.8, 0.6; p=0.738]. Compared to adults, adolescents had a lower SKF coefficient of variation (SKFcv) [0.34 (0.10) vs. 0.37 (0.09); difference-0.03; 95% CI, -0.06, -0.01; p=0.020] and subscapular-to-triceps ration (STR) [1.08 (0.28) vs. 1.29 (0.37); difference-0.21; 95% CI, -0.31, -0.12; p<0.001]. The largest Pearson moment correlation coefficient between vVO2max and SKF was shown in the subscapular (r=-0.411; 95% CI, -0.537, -0.284; p<0.001) and the smallest in the patellar anatomical site (r=-0.221; 95% CI, -0.356, -0.085; p=0.002). In addition, vVO2max correlated moderately with SKFavg (r=-0.390; 95% CI, -0.517, -0.262; p<0.001) and SKFcv (r=-0.334; 95% CI, -0.464, -0.203; p<0.001). CONCLUSIONS: In summary, CRF was related to the thickness of specific SKF and the magnitude of thickness variation by the anatomical site (i.e., the smaller the variation, the better the CRF). Considering the relevance of specific SKF for CRF, their further use would be recommended for monitoring physical fitness in soccer players.

How to end up on the podium after running a 6-days-run with type 1 diabetes mellitus - A case study and literature review.

BACKGROUND: An increasing number of people living with type 1 diabetes mellitus (T1DM) are pushing their physical limits to compete at the sport's highest level. Muscle, liver, and glycogen metabolism can be normal in athletes with diabetes with good glucose management, and modifications to insulin dose and nutrition can facilitate exercise performance. CASE PRESENTATION: We report on a 66-year-old runner with insulin-dependent T1DM. He has run over 90 marathons and ultra-marathons. Thanks to an insulin pump and continuous glucose monitoring, he has completed forty-eight 24-hour runs with an average performance of 133.8 km. Over the years, the runner increased his monthly running volume significantly and decreased his glycated Hemoglobin type A1C (hba1c) levels. Meanwhile, a significant association between monthly running kilometers and hba1c levels could be shown. At the age of 66 years, he finished his sixth 6-day-run in third place overall by covering a total distance of 467.424 km. CONCLUSIONS: These findings show that it is possible to participate in ultra-endurance events while suffering from T1DM without glucose derailing. With a good understanding of the disease and its impact on an individual's body, we can curtail the preparation and execution phases of ultra-endurance events to allow athletes to compete with minimal risk.

Performance improvement in sport through vitamin D - a narrative review.

OBJECTIVE: It is well known that vitamin D deficiency can lead to various health problems. However, it is not common knowledge among athletes and doctors that vitamin D deficiency is prevalent in sports. This deficiency can severely impact performance, while vitamin D supplementation can alleviate this effect and potentially improve performance. MATERIALS AND METHODS: This narrative review aims to compile the current state of knowledge about the importance of vitamin D in increasing performance for active people. To this end, we searched the 'Scopus' and 'PubMed' databases for the terms 'vitamin D - athlete - performance' with an end date of 30 June 2022. RESULTS: Study results indicated that the therapeutic impact of vitamin D on aerobic capacity, recovery, strength and sprint performance remains controversial. CONCLUSIONS: Based on the previous findings on recovery, strength and performance, 4,000-5,000 IU of vitamin D per day may be a safe dose that can improve athletic performance.

Factors associated with perceived performance drops and musculoskeletal injuries in Brazilian recreational triathletes.

OBJECTIVE: The aim of the study was to investigate sleep characteristics, use of supplements, and training volume of recreational triathletes, and to verify possible associations with perceived performance drops and occurrence of injuries. MATERIALS AND METHODS: Recreational triathletes (n=942) answered a questionnaire inquiring about their demographic characteristics, performance, injuries and training volume. RESULTS: When comparing athletes who slept more (9-10 hours) with those who slept less, less sleep was associated with a higher prevalence of perceived performance drops. Regarding difficulties in initiating sleep, the absence of initiating difficulties (p<0.001) was a protective factor against perceived performance drops. Regarding weekly training volume, compared to those who trained more than 20 hours, training less than 3 hours (p<0.001), 3-5 hours (p<0.001), or 12-14 hours (p<0.001) were protective factors against perceived performance drops. Concerning training volume and injuries, we found that compared to those who trained more than 20 hours, training 18-20 hours (p<0.001), 15-17 hours (p<0.001), 12-14 hours (p<0.001), 6-8 hours (p<0.001), or 3-5 hours (p<0.001) were protective factors against injuries. CONCLUSIONS: Triathletes with a lower sleep quantity and those who have difficulties initiating sleep frequently experience drops in performance. Training volumes can influence both performance and the likelihood of injuries.

Differences in pacing during cycling and running in ultra-triathlons - The example of 'Swissultra'.

OBJECTIVE: The knowledge of the most predictive split discipline and the pacing during a triathlon race is of utmost importance for planning an ultra-triathlon race. This study aimed at investigating the pacing during cycling and running splits in three different multi-stage ultra-triathlon race formats (i.e., Quintuple, Deca, and Double Deca Iron ultra-triathlon with 5x, 10x and 20x the daily distance of a full Ironman-distance triathlon). SUBJECTS AND METHODS: A total of 48 male ultra-triathletes competing in Quintuple (n=14), Deca (n=25), and Double Deca (n=9) Iron ultra-triathlon "swissultra" between 2016 and 2019 in Switzerland were analyzed. For each race day, we calculated the total performance (sum of all laps time), average individual performance (average of all laps time within a race day) and pacing variation (coefficient of variation of race laps time) for cycling and running. Discipline (cycling and running) and race distance (Quintuple, Deca, and Double Deca Iron ultra-triathlon) were used as independent parameters. The primary outcome variables were the time performance (daily and total) and the pacing variation. We applied two general linear models (GLM): the first model was a one-way ANOVA comparing total and daily performance by race distance, and the second model was a two-way ANOVA (race distance´ discipline) using pacing variation (average pace oscillation) as a dependent variable. RESULTS: The first GLM identified a significant race distance effect for total performance in both cycling (F = 375.6; p < 0.001; ηp2 = 0.943) and running (F = 267.8; p < 0.001; ηp2 = 0.922) with Double Deca Iron ultra-triathlon being the fastest and Quintuple Iron ultra-triathlon the slowest. The GLM for daily average performance showed no significant effect of race distance on cycling performance (F = 0.171; p = 0.843; ηp2 = 0.008), but on running performance (F = 6.408; p = 0.004; ηp2 = 0.222). The two-way GLM comparing pacing variation showed a significant effect for race distance (F = 11.81; p<0.001; ηp2 = 0.344) with Deca presenting larger pace variation than Quintuple and Double Deca Iron ultra-triathlon in both cycling and running, but not for discipline (F = 0.067; p=0.797; ηp2 = 0.001), nor for interaction (F = 1.469; p=0.241; ηp2 = 0.061). CONCLUSIONS: Athletes achieved a stable cycling performance independent of the length of the race, and the cycling split had an influence on the subsequent running split depending upon the length of the race.

Association between lowering restriction levels during the coronavirus outbreak and physical activity among adults: a longitudinal observational study in Brazil.

OBJECTIVE: The COVID-19 pandemic has had significant consequences on public health and lifestyle and has negatively affected mental health and the level of physical activity worldwide. This study examined the impact of reopening fitness centers and nonessential services and introducing flexible measures to ensure social distancing on physical activity and mental health. MATERIALS AND METHODS: This was a longitudinal study. A self-administered questionnaire, including personal, behavioral, physical activity, perception of health, and mood state disorder information, was answered by 128 Brazilians in June 2020 (during severe restrictive measures) and again in April 2021 (after fitness centers and nonessential services were reopened). RESULTS: The restriction level adopted in April 2021 was significantly lower than that in June 2020 (p<0.001). The level of physical activity (p<0.001) and health status perception (p<0.001) decreased from June 2020 to April 2021. The median values for depression and anxiety did not differ across the study period. CONCLUSIONS: The level of physical activity was reduced during the COVID-19 pandemic, and anxiety and depression were not improved following less restrictive social distancing measures and the reopening of fitness centers. Thus, the return to a prepandemic level of physical activity and mental health status may not be automatic. The results presented herein suggest that the decrease in physical activity observed in the population may be challenging in the postpandemic period.

Comparison of sleep characteristics during the first and second period of restrictive measures due to COVID-19 pandemic in Greece.

OBJECTIVE: The first wave of coronavirus pandemic and concomitant restrictive measures affected sleep. We slept more than usual, but the quality was worse. As the pandemic continues, a second period of restrictive measures was initiated, and no data exist about their impact on sleep. The aim of this study was to compare quantity and quality of sleep between the two periods of restrictive measures, due to the Coronavirus Disease-19 (COVID-19) pandemic in Greece. MATERIALS AND METHODS: A web-based survey using a short 13-item questionnaire was created and was distributed online. This included information about demographic and professional data, quantitative and qualitative characteristics of sleep, degree of abidance in lockdown measures, and data about COVID-19 infection or close contact with active confirmed cases. RESULTS: A total of 1,078 questionnaires were evaluated (first period, n=963; second period, n=115). Sleep duration was shorter during the second lockdown (mean difference -0.51h; 95% confidence interval, (CI), -0.82, -0.19, p=0.002). Compared to usual habits, sleep increased in first wave (mean difference +0.37h; 95% CI, 0.26, 0.47; p<0.001) and decreased in second wave (mean difference -0.35h; 95% CI, -0.60, -0.09; p=0.009). Regarding quality of sleep, less participants reported good quality of sleep during the second wave compared to the first (p=0.006). Finally, compliance to restriction measures was lower and the prevalence of confirmed illness or close contact with COVID-19 cases among participants was higher during the second period than during the first one (p<0.001 and p=0.028, respectively). CONCLUSIONS: Our data showed that sleep duration increased during the first lockdown and decreased in the second one, when compared to usual habits. Moreover, sleep quality progressively deteriorated, as the restrictive measures due to coronavirus pandemic continued.

Swimming during COVID-19: Operational recommendations and considerations for South African swimming venues.

Swimming is one of the most popular recreational activities in South Africa. Since the emergence of the Coronavirus disease 2019 (COVID-19), South Africa imposed one of the strictest lockdown measures to contain and control the spread of the virus. These measures included the closure of gyms, fitness centres and swimming pools across the country. However, as the restrictions begin to ease, it is important to consider how swimming facilities can reopen whilst simultaneously ensuring appropriate measures are in place to reduce COVID-19 infections. Outlined are recommendations and considerations for swimming facilities in South Africa. Currently there is no evidence to suggest that COVID-19 transmission to humans is possible through water, making swimming one of the safer options for physical activity indoors. However, participation is still not without risk and compliance with government mandates and public health officials take precedent over the recommendations outlined in this article.

Sex- and age-related differences in half-marathon performance and competitiveness in the world's largest half-marathon - the GöteborgsVarvet.

In road runners, the age-related performance decline has been well investigated for marathoners, but little is known for half-marathoners. We analysed data from 138,616 runners (48,148 women and 90,469 men) competing between 2014 and 2016 in GöteborgsVarvet, the world's largest half-marathon. The men-to-women ratio in participants increased with age, the fastest race times were observed in age groups ˂35 and 35-39 years in women and in age group 35-39 years in men, the main effect of sex and the sex × age group interaction on race time were trivial, and the competitiveness was denser in men and in the younger age groups. In summary, in half-marathon running in the largest half-marathon in the world, the GöteborgsVarvet, women achieved the fastest race time at an earlier age compared to men where the fastest race times were observed in women in age groups ˂35 and 35-39 years and in men in age group 35-39 years.

Performance trends in age-group runners from 100 m to marathon-The World Championships from 1975 to 2015.

This study examined changes in performance in age-group track runners across years from 1975 to 2015 for 100, 200, 400, 800, 1500, 5000, 10 000 m, and marathon and the corresponding sex differences. Athletes were ranked in 5-year age-group intervals from 35-39 to 95-99 years. For all races and all years, the eight female and male finalists for each age-group were included. Men were faster than women and this observation was more pronounced in the shorter distances. The younger age-groups were faster than the older age-groups and age exerted the largest effect on speed in 800 m and the smallest in marathon. There was a small variation of speed by calendar years. The competition density varied by sex and race distance. Half of participants were from USA, Germany, Australia, and Great Britain, but the participants' nationality varied by sex and race distance. In summary, the variation of competitiveness by sex in short race distances might be important for athletes and coaches. Considering the event's competitiveness and that athletes are participating in both 100 and 200 m or in 200 and 400 m, master women should be oriented to 200 m and master men should be oriented to 100 and 400 m.

Who runs the fastest? Anthropometric and physiological correlates of 20 m sprint performance in male soccer players.

The aim of the present study was to examine the relationship of 20 m sprint performance with anthropometrical and physiological parameters in male soccer players. A hundred and 81 soccer players from the region of Athens (age 23.4 ± 5.0 yrs, body mass 73.4 ± 7.7 kg, height 180.0 ± 5.9 cm, body fat (BF) 14.4 ± 3.6%), classified into quartiles according to 20 m sprint time (group A, 2.84-3.03 s; group B, 3.04-3.09 s; group C, 3.10-3.18 s; group D, 3.19-3.61 s), participated. Soccer players in group A were younger and had better performance in vertical jumps and in the Wingate anaerobic test (WAnT, p < 0.05). Sprint time correlated to age (r = 0.27), body mass (r = 0.23), body height (r = 0.20), BF (r = 0.23), vertical jumps (-0.58 ≤ r ≤ -0.50) and the WAnT (-0.45 ≤ r ≤ -0.30, p < 0.05). In summary, the magnitude of correlations of sprint time with measures of lower limbs muscle strength and power (WAnT and jumps) was larger than with anthropometric measures (body mass and BF).

THE EFFECT OF MATURITY ON HEART RATE RESPONSES DURING TRAINING AND TESTING IN POSTPUBESCENT FEMALE VOLLEYBALL PLAYERS.

The aim of this study was to examine the effect of maturity, assessed as difference between chronological age and age at peak height velocity, on heart rate (HR) responses to maximal and submaximal laboratory and field exercises. Twenty-eight postpubescent female volleyball players participated in the present study (age 13.8 (0.6) yr, body mass 62.5 (8.2) kg and height 1.73 (0.05) m; mean (standard deviation)). They were divided into two groups with regards to their maturation: less matured (LM) and more matured (MM). In laboratory, HR was recorded during 5 min rest, physical working capacity in heart rate 170 bpm, 3 min step test, 30 s Bosco test and Wingate anaerobic test (WAnT) were performed. In field, a 70 min training session (consisted by three parts: warm-up, 1 x 1 drills and team drills) was monitored and 20 m shuttle run endurance test was performed. There was significant difference between LM and MM groups over HR responses (%HR reserve, %HRR) to exercise training (F(2,21) = 6.08, p = 0.008, η2 = 0.37). There was a main effect of part session of exercise program on HR responses with the highest intensity recorded in 1 x 1 drills (-75% HRR) and the lowest in team drills (-60% HRR in LM and -65% HRR in MM). There was also a moderate effect of maturity on HR during cycling against 90 W and in the WAnT, and small effect on HR during cycling against 60 W, in the end of the step test, Bosco test and running endurance test, where the highest scores were recorded in LM. Based on the findings of the present study, it was concluded that maturity exerted an effect of small to moderate magnitude on H R responses in a laboratory setting and this should be taken into account by coaches and trainers when evaluating physiological characteristics.

Physical and physiological characteristics in male team handball players by playing position - Does age matter?

AIM: The purpose of this study was to examine the variation in physical and physiological characteristics according to playing position in adolescent and adult male team handball (TH) players. METHODS: Adolescent (N.=57, aged 14.9±1.4 yr) and adult (N.=39, 26.6±5.7 yr) players were examined for anthropometric characteristics, somatotype and body composition, and performed the physical working capacity test, a force-velocity test, the Wingate anaerobic test (WAnT), sit-and-reach test, handgrip strength test, squat jump (SJ), countermovement vertical jump without (CMJ) and with arm-swing, and a 30-s Bosco test. Eccentric utilization ratio (EUR) was calculated as the ratio CMJ to SJ. RESULTS: In adult players, there were significant differences between wings and the other positions with regard to anthropometric and body composition parameters (body mass, -17.9% to -13.2%; height, -5.3% to -4.3%; and fat-free mass, -13.7% to -9.9%) and anaerobic power assessed by WAnT (peak power, -20.5% to -15.2%; and mean power, -20% to -14.8%); however, these characteristics did not differ significantly in adolescents, in which the only statistically significant difference was found between goalkeepers and the other positions in EUR (+8.1%). CONCLUSION: Therefore, the differences in physical and physiological characteristics between playing positions are age-dependent. As adult players in this study were taken from players competing in the top Greek league, findings could serve as a base for talent identification and development for future studies. Moreover, knowledge about positional differences might enhance the ability to make tailored position-specific training programs among adult and adolescent players in the future.

Relationship between Nutrition Knowledge and Physical Fitness in Semiprofessional Soccer Players.

Whereas nutrition has a crucial role on sport performance, it is not clear to what extent nutrition knowledge is associated with physical fitness. The aim of this study was to examine the current level of nutrition knowledge of soccer players and whether this level is associated with physical fitness. Soccer players (n = 185, aged 21.3 ± 4.9 yr, weight 72.3 ± 8.4 kg, and height 177.5 ± 6.4 cm) performed a battery of physical fitness tests (sit-and-reach test, SAR; physical working capacity in heart rate 170, PWC170; and Wingate anaerobic test, WAnT) and completed an 11-item nutrition knowledge questionnaire (NKQ). Low to moderate Pearson correlations (0.15 < r < 0.34, p < 0.05) of NKQ with age, weight, height, fat free mass (FFM), SAR, peak power, and mean power of WAnT were observed. Soccer players with high score in NKQ were older (4.4 yr (2.2; 6.6), mean difference (95% confidence intervals)) and heavier (4.5 kg (0.6; 8.3)) with higher FFM (4.0 kg (1.1; 6.8)) and peak power (59 W (2; 116)) than their counterparts with low score. The moderate score in the NKQ suggests that soccer players should be targeted for nutrition education. Although the association between NKQ and physical fitness was low to moderate, there were indications that better nutrition knowledge might result in higher physical fitness and, consequently, soccer performance.

The relationship between body mass index and physical fitness in adolescent and adult male team handball players.

The main objective of this study is to examine the relationship between elevated Body Mass Index (BMI) and selected physical fitness variables in male handball players. In addition, we investigated whether this relationship is age-dependent, i.e., whether a higher BMI has the same implications for physical fitness in adolescents as in adult players. Therefore, adolescent (n = 57, aged 14.9 +/- 1.4 yr) and adult (n = 39, 26.6 +/- 5.7 yr) participants performed a series of anthropometric and physical fitness measures. In adolescent players, BMI was inversely related with countermovement jump (r = -0.26, P < 0.05), mean power during a 30-s Bosco test (r = -0.30, P < 0.001) and handgrip muscle strength (r = -0.52, P < 0.001). Further, BMI was in direct relationship with fatigue index of the Wingate anaerobic test (r = 0.29, P < 0.05). Correspondingly lower and non-significant correlations were found in adult players. Also, in the latter players, there was an inverse association between BMI and maximal anaerobic power during the force-velocity test (r = -0.34, P < 0.05). The present findings indicate that elevated BMI is more strongly inversely related to physical fitness in adolescent compared to adult team handball players.

Overweight and obesity in male adolescent soccer players.

AIM: In spite of the increasing scientific interest in the epidemiology of overweight and obesity in children and adolescents, less attention was paid to the prevalence of these disorders in sport setting. The aim of this study was to investigate the prevalence of overweight and obesity in adolescent soccer players. METHODS: Male adolescent (N.=297 aged 12.01-20.98 y), classified in nine one-year age-groups, children (control group, N.=16 aged 7.34-11.97 y) and adult players (control group, N.=29 aged 21.01-31.59 y), all members of competitive soccer clubs, performed a series of anthropometric measures (body mass, height, skinfolds and circumferences), from which body mass index (BMI), percentage of fat (BF), fat mass (FM), fat free mass (FFM) and waist-to-hip ratio (WHR) were calculated. RESULTS: After having partitioned out the effect of age on the parameters of body composition, BMI was associated moderately to strongly with BF, FM and FFM (r=0.74, r=0.88 and r=0.68, P<0.001), while there was no corresponding relationship between WHR and BF (r=0.03, P=0.64). The prevalence of overweight/obese ranged 13.3-32.4%. Although there was no difference between adolescent age groups, the difference between adult and child control group (χ2=7.09, P<0.05; higher prevalence in children than in adults) indicated an attenuation of this prevalence with development. CONCLUSION: Based on these findings, the prevalence of overweight/obesity in adolescence was confirmed. However, what was novel was that this phenomenon was identified in adolescent sport setting and, consequently, exercise interventions with proper mode, duration and intensity, targeting this phenomenon, should be applied by coaches and fitness trainers.

Cardiorespiratory power across adolescence in male soccer players.

Despite the recognition of the beneficial role of cardiorespiratory power (CRP) for health and sport performance, the development of this physical fitness parameter in adolescent soccer players was not well studied. Aim of this cross-sectional study was to investigate the effect of age on CRP of adolescent soccer players, the influence of anthropometric characteristics and body composition on it, and to establish normative data. Male adolescent (N=274; aged 12.07-20.98 y), classified in nine one-year age-groups, child (N=12, aged 7.71-11.8 y) and adult players (N=22; aged 21.12-31.59 y), all members of competitive soccer clubs, were examined for anthropometric characteristics and body composition and they performed Physical Working Capacity in heart rate 170 test (PWC170) on cycle ergometer. Analysis of variance revealed significant difference between age groups with respect to PWC170 in absolute (F10.297 = 29.58, P < 0.001, eta2 = 0.5), relative to body mass (F10.297 = 5.28, P < 0.001, eta2 = 0.15) and relative to fat free mass values (F10.297 = 4.98, P < 0.001, eta12 = 0.14). In addition, age was in positive association with these parameters (r = 0.6, P < 0.001, r = 0.24, P < 0.001 and r = 0.23, P < 0.001, correspondingly). The main finding of this study was that CRP increased during developmental period in soccer players, even when it was adjusted to body mass or FFM, which increased during development. This documentation of the development of CRP provided useful tool for coaches and fitness trainers in order to apply optimal exercise interventions for health and performance.