Vigorous physical activity patterns affect bone growth during early puberty in boys.

This study aims to analyze the impact of participation in vigorous physical activity as it can promote a healthy bone development. Adolescents who increased their participation in vigorous physical activity showed higher improvements in bone parameters compared to those who did not, which highlights the relevance of vigorous physical activity engagement. INTRODUCTION: The main purpose of the study was to analyze the effects of different patterns of vigorous physical activity (VPA) on bone development. METHODS: One-week accelerometry registers and dual-energy X-ray absorptiometry scans at the whole body, hip, and lumbar spine of 140 healthy male adolescents (11-13 years, at baseline) were performed twice with a 1-year interval between measurements. Four patterns of VPA evolution ("low-low," "low-high," "high-low," and "high-high") and three patterns of bone growth ("optimal," "mean," and "reduced") were defined according to the median participation in VPA and a cluster analysis of the longitudinal changes in BMC and BMD in all sites measured, respectively. Bone mineral parameters were adjusted for skeletal age and body weight prior to statistical comparison among groups. RESULTS: Participants in the "low-high" group had greater adjusted BMD increases at both the femoral neck and lumbar spine when compared to the "low-low" group (estimated mean (95% CI) 0.066 (0.047-0.085) vs. 0.034 (0.021-0.047) g/cm2 and 0.074 (0.054-0.093) vs. 0.049 (0.035-0.062) g/cm2 respectively, both p < 0.05). Femoral neck BMD adjusted increase was also different between the "high-high" and the "high-low" groups (0.053 (0.041-0.066) vs. 0.030 (0.011-0.049) g/cm2, p < 0.05). Additionally, a higher percentage of "optimal" growth was found in the "low-high" group than in the "low-low" and "high-low" categories (36.3, 12.5 and 13.6% respectively, p < 0.05). CONCLUSIONS: Engaging in VPA as well as maintaining high levels of VPA during puberty is associated with greater gains in bone mass, which can have an impact in future bone health.

Longitudinal associations of android and gynoid fat mass on cardiovascular disease risk factors in normal weight and overweight boys during puberty.

OBJECTIVES: The aim of this longitudinal study was to assess associations between android and gynoid fat distribution and different cardiovascular disease risk factors in normal weight as well as overweight/obese boys during the pubertal period. METHODS: In total, 146 boys (baseline age 11.9 ±0.6 years) were recruited for a 2-year longitudinal study. Total body fat percentage and android-gynoid fat distribution were measured using DXA. In addition, waist and hip circumference was measured and body mass index (BMI) was calculated. Total cholesterol, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol, triglycerides, insulin and glucose were measured, and homeostatic model assessment-insulin resistance (HOMA-IR) was calculated. Tanner stage and physical activity were assessed as covariates. RESULTS: Overweight subjects had worse values for most of the measured blood parameters (P <0.05). Higher android, gynoid fat mass (FM), and android/gynoid FM ratio were longitudinally associated with higher insulin and HOMA-IR values in both normal weight and overweight boys (P <0.05). In addition, higher android FM and gynoid FM were associated with worse values in HDL cholesterol, LDL cholesterol, and triglycerides in overweight boys (P <0.05). CONCLUSIONS: Our results suggest that higher android as well as gynoid fat have a strong impact on cardiovascular disease risk factors in both normal weight and overweight boys during the pubertal period. It can be suggested that measurement of fat distribution as android and gynoid fat is important for the assessment of the development or burden of metabolic diseases in boys with different weight statuses.

Low fitness is associated with metabolic risk independently of central adiposity in a cohort of 18-year-olds.

It is unclear whether cardiorespiratory fitness (CRF) remains associated with metabolic risk if controlled for central adiposity and other confounders; thus, the aim of this study was to investigate the independent effect of CRF on metabolic syndrome risk factors in relatively homogeneous age group of young adults. In this cross-sectional study, 828 participants performed CRF test on a cycle ergometer (Wmax kg ) and were categorized into sex-specific tertiles. Continuous metabolic syndrome risk score (MetS-score) was calculated as the sum of standardized scores of five metabolic syndrome risk factors: glucose, mean arterial pressure, low-density lipoprotein cholesterol, triglycerides, and total cholesterol/high-density lipoprotein cholesterol ratio. Low fitness group had higher values in all measured metabolic syndrome parameters, except for cholesterol parameters, compared to high fitness group. The unadjusted model indicated that CRF was negatively associated with clustered metabolic risk (ß = -0.116, P = .001). After the adjustment of smoking habits, sports training participation, and waist circumference, the association between CRF and MetS-score slightly increased (ß = -0.126; P < .001). Low CRF was associated with increased risk (OR = 2.58 (95% CI 1.50-4.41)) for higher MetS-score after adjustment for potential confounders and waist circumference. The results of our study indicate that being highly fit increases the likelihood of having lower MetS-score for approximately 2 and 2.5 times independently of central adiposity compared to average and low fitness, respectively. In conclusion, it is highly important to improve CRF through regular exercise, not focusing just on body composition in young adulthood in every weight status group.

VO2 Kinetics in All-out Arm Stroke, Leg Kick and Whole Stroke Front Crawl 100-m Swimming.

The VO2 response to extreme-intensity exercise and its relationship with sports performance are largely unexplored. This study investigated the pulmonary VO2 kinetics during all-out 100-m front crawl whole stroke swimming (S), arm stroke (A) and leg kick (L). 26 male and 10 female competitive swimmers performed an all-out S trial followed by A and L of equal duration in random order. Breath-by-breath VO2 was measured using a snorkel attached to a portable gas analyzer. Mean (±SD) primary component parameters and peak blood lactate (Lapeak) during S, A, and L were, respectively: time delay (s), 14.2 ± 4.7, 14.3 ± 4.5, 15.6 ± 5.1; amplitude (ml·kg(-1)·min(-1)), 46.8 ± 6.1, 37.3 ± 6.9, 41.0 ± 4.7; time constant (τ, s): 9.2 ± 3.2, 12.4 ± 4.7, 10.1 ± 3.2; Lapeak (mmol·l(-1)), 6.8 ± 3.1, 6.3 ± 2.5, 7.9 ± 2.8. During A and L respectively, 80% and 87% of amplitude in S was reached, whereas A+L were 68% greater than in S. 100-m performance was associated to shorter cardiodynamic phase and greater VO2 amplitude and Lapeak (accounting up to 61% of performance variance), but not to τ. We conclude that (i) VO2 gain was proportional to exercise intensity and muscle mass involved, (ii) kicking is metabolically less efficient, and (iii) the main limiting factor of peak VO2 appears to be O2 delivery and not muscle extraction.

Better economy in field running than on the treadmill: evidence from high-level distance runners.

Given the ongoing interest in ways to improve the specificity of testing elite athletes in their natural environment, portable metabolic systems provide an opportunity to assess metabolic demand of exercise in sport-specific settings. Running economy (RE) and maximal oxygen uptake ([Formula: see text]O2max) were compared between track and treadmill (1% inclination) conditions in competitive level European distance runners who were fully habituated to treadmill running (n = 13). All runners performed an exercise test on running track and on treadmill. While [Formula: see text]O2max was similar on the track and on the treadmill (68.5 ± 5.3 vs. 71.4 ± 6.4 ml·kg(-1)·min(-1), p = 0.105, respectively), superior RE was found on the track compared to the treadmill (215.4 ± 12.4 vs. 236.8 ± 18.0 O2 ml·kg(-1)·km(-1), p < 0.001). RE on the track was strongly correlated with RE on the treadmill (r = 0.719, p = 0.006). The present findings indicate that high-level distance runners have significantly better RE but not [Formula: see text]O2max on the track compared to treadmill. This difference may be due to biomechanical adjustments. As RE is strongly correlated between the two conditions, it would be reasonable to assume that interventions affecting RE on the treadmill will also affect RE on the track.

Serum interferon gamma concentration is associated with bone mineral density in overweight boys.

UNLABELLED: Childhood obesity has recently been linked to low-grade inflammation. Overweight children have slightly different processes of bone accumulation than normal weight children. The possible links between inflammation and bone accumulation have not previously been assessed in overweight children. AIMS: An exploratory study to assess whether common inflammatory markers are associated with the development of obesity and bone accumulation in childhood. METHODS: Thirteen different inflammatory markers in serum were measured in 38 boys with BMI >85th centile (overweight) and 38 boys with normal BMI (normal weight), aged 10-11 years. Total body (TB) and lumbar spine (LS) bone mineral density (BMD), bone mineral content (BMC) were measured by DXA. TB BMC for height, TB and LS bone mineral apparent density (BMAD) were calculated. RESULTS: Overweight boys had higher mean TB and LS BMD, TB BMC and TB BMC for height, but lower mean TB BMAD (all p < 0.05) than normal weight boys. Serum interferon gamma (IFNγ) concentration was significantly (p < 0.05) correlated with TB BMD (r = 0.36), TB BMC (r = 0.38) and TB BMC for height (r = 0.53) in the broader overweight group (n = 38). In obese boys (BMI > 95 centile, n = 36) IFNγ was correlated with LS BMD (r = 0.38). CONCLUSION: The positive correlation between serum INFγ concentration and BMD suggests that the inflammatory process, already involved in the early stage of obesity, may also affect bone accumulation. Further studies are needed to clarify the role of INFγ as a possible link between adipose tissue and bone health.

Anthropometry and somatotypes of competitive DanceSport participants: a comparison of three different styles.

Anthropometry in dance and aesthetic sports has been shown to play an important role in selection and performance criteria. The aim of the present study was to examine variations in somatotype and anthropometry in three different competitive dance styles: DanceSport Standard, Latin American and Ten Dance. Anthropometry and somatotype data were collected from thirty couples competing in Standard (n=24 individuals), Latin American (n=14) and Ten Dance (n=22) styles. A single tester (ISAK Level 1) carried out all anthropometric measurements using the Heath-Carter protocol and somatotypes were calculated using the Heath-Carter's decimal equations. Results indicated that the mean somatotype for the male dancers was 2.4-3.9-3.2, whilst for females it was 2.7-2.7-3.5. Factorial analysis reported Standard dancers scored significantly higher for ectomorphy, sitting height and arm span than Latin dancers (p<0.05). Correlation analysis with the Standard dancer's International Ranking highlighted moderate positive correlation with mesomorphy (r=0.434, p<0.05) and negative correlation with ectomorphy (r=-0.546, p<0.001). The findings of this study show that somatotypes differ among DanceSport participants by dance style. Compared with other aesthetic sports, male and female dancers were less mesomorphic and more ectomorphic. Standard dancers tend to be more ectomorphic with greater height, longer arm span and greater sitting height compared with Latin American dancers. Although Standard dancers were ectomorphic, those dancers who had higher mesomorphic ranking had higher places in the dancers' international ranking.

Running economy and body composition between competitive and recreational level distance runners.

The aim of the present study was to compare running economy between competitive and recreational level athletes at their individual ventilatory thresholds on track and to compare body composition parameters that are related to the individual running economy measured on track. We performed a cross-sectional analysis of a total 45 male runners classified as competitive runners (CR; n = 28) and recreational runners (RR; n = 17). All runners performed an incremental test on treadmill until voluntary exhaustion and at least 48 h later a 2 × 2000 m test at indoor track with intensities according to ventilatory threshold 1, ventilator threshold 2. During the running tests, athletes wore portable oxygen analyzer. Body composition was measured with Dual energy X-ray absorptiometry (DXA) method. Running economy at the first ventilatory threshold was not significantly related to any of the measured body composition values or leg mass ratios either in the competitive or in the recreational runners group. This study showed that there was no difference in the running economy between distance runners with different performance level when running on track, while there was a difference in the second ventilatory threshold speed in different groups of distance runners. Differences in running economy between competitive and recreational athletes cannot be explained by body composition and/or different leg mass ratios.

Elevated serum IL-6, IL-8, MCP-1, CRP, and IFN-γ levels in 10- to 11-year-old boys with increased BMI.

BACKGROUND/AIMS: Many inflammation parameters are associated with obesity, but few comparable data are found in youth. This study aims to characterize the differences in serum levels of 13 biochemical inflammatory markers between boys with increased BMI and boys with normal BMI, and examine the relationships between inflammation markers, skinfold thicknesses, and body composition. PARTICIPANTS/METHODS: The participants were 38 boys (BMI above 85th percentile) and 38 boys (normal BMI) at the age of 10-11 years. Measurements included BMI, 9 skinfold thicknesses, waist and hip circumferences, and total body and trunk fat mass and percentage as indices of obesity, fasting insulin, glucose, and serum concentrations of IL-2, IL-4, IL-6, IL-8, IL-10, VEGF, IFN-γ, TNF-α, IL-1α, IL-1ß, monocyte chemoattractant protein-1 (MCP-1), epidermal growth factor, and CRP. RESULTS: Overweight boys (OWB) were taller and more frequently in puberty than normal-weight boys (NWB). Skinfold thicknesses and body composition parameters were higher in OWB. They had significantly higher serum IL-6, IL-8, IFN-γ, MCP-1, and CRP values compared to NWB. CONCLUSIONS: Six of 13 measured biochemical markers were significantly increased in OWB, indicating that many low-grade inflammatory processes are already involved in the development of obesity in childhood.

The effect of 4-week training period on plasma neuropeptide Y, leptin and ghrelin responses in male rowers.

The aim was to investigate the effect of high-volume low intensity resistance training protocol combined with endurance training on plasma neuropeptide Y (NPY) concentration in rowers. Additionally, leptin and ghrelin, as markers for body energy balance concentrations, were monitored. 12 highly trained national and international level male rowers participated in this study. The participants were tested three times--after reference week (T1), after 2 weeks of high-volume training (T2) and after a recovery week (T3) for aerobic performance, energy intake and expenditure, and blood biochemical parameters. The submaximal rowing performance decreased significantly (P = 0.019) at T2. Fasting leptin decreased significantly (from 2.05 ± 0.88 to 1.28 ± 0.53 ng/mL; P = 0.009) at T2 and increased significantly (from 1.28 ± 0.53 to 1.79 ± 0.79 ng/mL; P = 0.002) at T3. Fasting ghrelin decreased significantly (from 980 ± 300.2 to 873.35 ± 198.6 pg/mL; P = 0.036) at T3 compared to T2, while no changes were found in fasting NPY. Significant decreases in exercise-induced leptin were observed at T2 (from 1.13 ± 0.5 to 1.08 ± 0.5 ng/mL; P = 0.012), PRE and POST test leptin values at T2 were significantly decreased compared to T1(1.40 ± 0.9 to 1.13 ± 0.5 and 1.44 ± 0.8 to 1.08 ± 0.5, respectively). Acute exercise-induced increases in NPY were found at T2 (from 128.1 ± 23.2 to 155.1 ± 28.9 pmol/L; P = 0.002) and at T3 (from 131.3 ± 20.5 to 159.7 ± 32.8 pmol/L, P = 0.004). In conclusion, the combination of high-volume training protocol and energy imbalance induces significant post-exercise changes in NPY, leptin, and ghrelin concentrations and decreases fasting leptin.

Interactions between adipose, bone, and muscle tissue markers during acute negative energy balance in male rowers.

AIM: The purpose of this investigation was to study the influence of prolonged low-intensity single scull rowing exercise on plasma adipocytokine and osteokine concentrations in trained male rowers. Nine single scull rowers (age: 20.1±1.6 yrs; height: 184.1±4.6 cm; body mass: 81.2±5.3 kg; %body fat: 11.1±3.9) participated in this study. METHODS: Venous blood samples were obtained before and after a ~2 h constant load on-water sculling training session (distance: 20.6±1.5 km; HR: 133±4 bpm; intensity: 80.3±1.7% of the HR turn-point). RESULTS: The training session created an energy deficit of 1 200-1 500 kcal. Plasma adiponectin increased (+12.2%; P<0.05) while leptin decreased (-23.1%; P<0.05) at 30 min postexercise. Plasma osteocalcin (+23.7%; P<0.05) and type I carboxyterminal telopeptide (ICTP) (+28.6%; P<0.05) were increased on completion of the training session. Plasma IL-6 concentration was increased (P<0.05) about four-fold while insulin concentration was decreased (P<0.05) more than three-fold upon completion of exercise. There were no differences in TNF-α, glucose, testosterone and cortisol concentrations over time. Plasma adiponectin (r=0.59) and osteocalcin (r=0.57) concentrations measured immediately after the training session were related (P<0.05) to the distance covered. CONCLUSION: Acute negative energy balance induced by a single endurance rowing training session elicited an inverse metabolic response in adiponectin and osteocalcin concentrations in male rowers. Our results suggest that peripheral markers of negative energy balance, such as adiponectin and osteocalcin, may serve as signals for metabolic reaction to the energy cost of acute exercise in athletes.

Adiponectin and bone metabolism markers in female rowers: eumenorrheic and oral contraceptive users.

This study investigated whether adiponectin, bone formation (osteocalcin) and bone resorption [type I carboxyterminal telopeptide (ICTP)] values are influenced by menstrual cycle phase and oral contraceptive use in female rowers. Twenty-four rowers divided into normally cycling athletes (NOC; no.=15) and athletes taking oral contraceptive pills (OC; no.=9) participated in this study. Fasting blood samples, body composition and aerobic capacity measurements were taken during the follicular (FP) and the luteal (LP) phases of the menstrual cycle. Adiponectin, insulin, glucose, insulin resistance, body composition and aerobic capacity did not fluctuate significantly during menstrual cycle in both groups. Osteocalcin and ICTP were lower (p<0.05) in OC compared with NOC, but did not change significantly across menstrual cycle phases in both groups. Estradiol and progesterone were not related to adiponectin, osteocalcin or ICTP (r<0.147; p>0.05). Adiponectin was correlated (p<0.05) with osteocalcin (r=0.452) and fat free mass (r=0.428), and osteocalcin was related (p<0.05) to insulin (r=-0.413), glucose (r=-0.486) and insulin resistance (r=-0.528). In conclusion, adiponectin was not affected by menstrual cycle phase and OC use in female rowers, while bone metabolism markers were lower in OC compared to NOC groups. Adiponectin and osteocalcin were interrelated and may characterise energy homeostasis in female athletes.

Performance improvement is associated with higher postexercise responses in interleukin-6 and tumor necrosis factor concentrations.

AIM: The aim of this study was to investigate the postexercise concentrations in IL-6 and TNF-α during maximal 6000 meter time trial in conditions with improved performance capacity. METHODS: Nine highly trained male rowers (age 19.67±1.0; height 190.67±4.24 cm; weight 91.07±6.24 kg) participated. Subjects were asked for body composition measurement and two 6000 meter all-out rowing ergometer trial separated by one year. RESULTS: The 6000 meter rowing ergometer performance was significantly improved during one year period from from Test 1 to Test 2 (from 330.3±21.9 W to 349.2±20.3 W, P<0.05). No significant changes were observed in the anthropometrical parameters. Postexercise cortisol and IL-6 were significantly increased during both testing sessions, while TNF-α was only increased after Test 2 when compared to pretest values. Postexercise and post 30 values of TNF-α were significantly higher at Test 2 compared to Test 1, while only Post 30 values of IL-6 were significantly higher at Test 2 compared to Test 1. There were no significant relationship between postexercise IL-6 and TNF-α concentrations and the 6000 meter rowing ergometer performance (r=-0.101 - -0.617; P>0.05) and no signigficant relationships between the measured body compositional and blood biochemical parameters. Postexercise changes in IL-6 concentration were significantly related to changes in performance (r=-0.667 and r=-0.865 for POST and POST 30, respectively; P<0.05). CONCLUSION: In conclusion improvements in performance resulted in higher postexercise concentrations of IL-6 and TNF-α in highly trained male rowers.

HRTP, prolonged ergometer exercise, and single sculling.

The use of the heart rate turn point (HRTP) to set target heart rate (THR) for prolonged rowing ergometer (E) and single scull rowing (R) was evaluated. Ten trained subjects (age 21.3 +/- 4.0 yrs; VO (2max) 4.77 +/- 0.62 l . min-1) performed incremental exercise tests and 30-min prolonged E and R. Expired air and heart rate (HR) were measured continuously. During E and R, blood lactate concentration (La) was measured at rest and after 5, 10, 20, and 30 min. HRTP and V (E)TP (2) were determined as the deflection point of the heart rate performance curve and the second TP in minute ventilation (V. (E)). No significant differences were found for work rate (W), HR, and VO (2) between HRTP and V. (E)TP (2) and they were significantly related (r = 0.94, p < 0.001; r = 0.96, p < 0.001). Mean HR, VO (2), VCO (2), and V. (E) were not significantly different between E and R. La remained at a steady state in both E and R but was slightly higher in E. Tidal volume (V (T)) was found to be lower and breathing rate (BR) was significantly higher in R. HR at HRTP from an incremental rowing ergometer exercise test is valid to establish a THR consistent with constant metabolic training intensity in prolonged ergometer and single scull rowing.

Plasma adiponectin response to sculling exercise at individual anaerobic threshold in college level male rowers.

The purpose of the investigation was to study plasma adiponectin response to a single exercise session in male rowers. Eight college level, single scull rowers (VO2max: 5.01+/-0.43 l.min-1; age: 21.5+/-4.5 yrs; height: 184.9+/-5.0 cm; body mass: 78.5+/-8.4 kg; body fat: 11.8+/-1.2%) participated in this study. Venous blood samples were obtained before, immediately after, and following the first 30 min of recovery of constant load on-water rowing over a distance of 6.5 km (approximately 30 min) at the individual anaerobic threshold (75.2+/-2.9% of VO2max). Adiponectin was unchanged (p>0.05) immediately after the exercise. However, adiponectin was significantly increased above the resting value after the first 30 min of recovery (+14.7%; p<0.05). Similarly, leptin was unchanged immediately after exercise and was significantly decreased after the first 30 min of recovery (-18.2%; p<0.05). Plasma insulin was significantly reduced immediately after exercise and remained significantly lower during the first 30 min of recovery period. Glucose increased with exercise and returned to the pre-exercise level after the first 30 min of recovery. Basal adiponectin was significantly related to VO2max (r=-0.62; p=0.034). However, there was no relationship between basal adiponectin and other measured variables. Similarly, basal leptin demonstrated no relationship with other measured variables. In conclusion, the results of the present study suggest that plasma adiponectin is sensitive in the first 30 min of recovery to the effects of relatively short-term exercise at individual anaerobic threshold when all major muscle parts are involved.

Hormonal response to maximal rowing before and after heavy increase in training volume in highly trained male rowers.

AIM: The aim of this study was to investigate the hormonal response at rest and during maximal 2,000 m rowing ergometer test in 12 highly trained male rowers before and after 3 week heavy training, and after 2 week tapering periods. METHODS: Venous blood samples were obtained before, immediately after and after 30 min of recovery of the rowing performance test. Testosterone, cortisol and sex hormone binding globulin were measured, and free testosterone and the free testosterone: cortisol ratio calculated. RESULTS: Mean training time was about 100% higher during the heavy training period (17.5 h x week(-1)) compared to the tapering period (8.9 h x week(-1)). Two thousand meter rowing ergometer performance parameters were not different between 3 tests. Resting testosterone and cortisol values were not different between 3 tests. Three week heavy training period induced significant reductions in resting free testosterone and free testosterone: cortisol ratio. Resting free testosterone and free testosterone: cortisol ratio were increased to the pretraining level after 2 week tapering period. A significantly (p<0.05) lower maximal exercise-induced increase of the free testosterone level was measured after heavy training period. The response of cortisol was unchanged and free testosterone: cortisol ratio demonstrated a trend (p>0.05) for a decrease after heavy training period. CONCLUSIONS: Our findings indicate that the first sign of decreased adaptivity in athletes is a decreased resting level of free testosterone and a lower maximal exercise-induced increase in free testosterone concentration. In addition, heavy training load higher than 1,000 min per week can be sustained for 3 weeks when sufficient tapering period is followed in highly trained male rowers.

Changes in stress and recovery after heavy training in rowers.

In this study, the effect of rapidly increased training volume on performance, recovery-stress state and stress hormones over a six-day training camp were investigated in competitive male rowers (n=21). The training regimen consisted mainly of low-intensity on-water rowing and resistance training, in total 19.6+/-3.8 hrs, corresponding to approximately 100% increase in training load. Two thousand metre rowing ergometer performance time worsened by the end of a heavy training period. The resting blood testosterone decreased and cortisol remained unchanged. The Recovery-Stress-Questionnaire for Athletes (RESTQ-Sport) revealed an increase in somatic components of stress (Fatigue, Somatic Complaints, Fitness/Injury) and a decrease in recovery factors (Success, Social Relaxation, Sleep Quality, Being in Shape, Self-Efficacy). Relationships were observed between training volume, and Fatigue (r=0.49), Somatic Complaints (r=0.50) and Sleep Quality (r=-0.58) at the end of heavy training. In addition, relationships were also observed between cortisol and Fatigue (r=0.48) at the end of heavy training as well as between changes in cortisol and changes in Fatigue (r=0.57) and Social Stress (r=0.51). In conclusion, changes in specific stress and recovery scales of the RESTQ-Sport for athletes and changes in stress hormone values indicated a state of heavy training stress and incomplete recovery at the end of a six-day heavy training period.

Hormonal reactions during heavy training stress and following tapering in highly trained male rowers.

The purpose of this study was to determine whether fasting plasma leptin, cortisol, testosterone and growth hormone concentrations were altered with a heavy increase in training stress followed by a reduced stress in highly trained male rowers. Twelve male national standard rowers (age 20.5 +/- 3.0 years, height 187.9 +/- 6.1 cm, body mass 87.1 +/- 8.3 kg, percent body fat 10.4 +/- 3.2 %) underwent a three-week period of maximally increased training stress followed by a two-week tapering period. The fasting blood samples were obtained every week after the rest day. In addition, the maximal 2000-meter rowing ergometer performance time was assessed before and immediately after the exhaustive training period as well as after the tapering period. A 22 % increase in training stress caused a significant decrease (by 8 %) and increase (by 9 %) in leptin and testosterone, respectively. A further increase in training volume by 25 % significantly reduced leptin further by 35 %. At the same time, no changes were observed in testosterone. Growth hormone was significantly elevated only after the first week of heavy training stress compared to the pretraining level. In the first tapering week, where the physical stress was reduced by 50 %, leptin only significantly increased by 29 %. Testosterone and growth hormone were significantly reduced to almost pretraining levels by the end of the second tapering week. Leptin was further significantly increased during the second tapering week. Cortisol remained relatively constant during the whole study period. Similarly, rowing performance was not significantly changed. We conclude that leptin is more sensitive to the rapid and pronounced changes in training stress compared to measured stress hormones in athletes. In addition, fasting plasma leptin could be regarded as a key signal for metabolic adaptation to exhaustive training stress in highly trained male rowers.