The associations between the changes in serum inflammatory markers and bone mineral accrual in boys with overweight and obesity during pubertal maturation: a 3-year longitudinal study in Estonian boys.

Adipose tissue produces different inflammatory cytokines which compromise bone mineral accrual during puberty. Vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), interleukin (IL)-8, and interferon-gamma (IFN-γ) are significantly related to bone mineral accrual during pubertal maturation in boys with different BMI values. INTRODUCTION: This longitudinal study aims to identify the inflammatory markers that most strongly associate with pubertal bone mineral density (BMD) increment in boys with overweight and obesity (OWB). METHODS: Twenty-six OWB and 29 normal-weight boys were followed yearly for 3 years to measure changes in 12 serum inflammatory markers, BMD (by DXA), and apparent volumetric BMD. The OWB group was further divided into two subgroups according to their BMI gain during the 3-year period. Data through time points presented as slopes were used to calculate correlation coefficients to explore the possible relationships between variables of interest. In the whole study group, linear mixed effects (LME) models were also used. RESULTS: Increment in serum VEGF concentration was inversely associated with an increase in total body (TB) BMD (r = - 0.82, P = 0.02) and TB bone mineral content (BMC)/height (r = - 0.82, P = 0.02) in those OWB whose BMI gain was higher during pubertal years. In the whole study group, the LME model confirmed the inverse association between VEGF and TB BMC/height (P < 0.05). EGF was inversely associated with LS BMD and LS BMAD (P < 0.05), whereas there was a positive association between IL-8 and TB BMAD and between IFN-γ and LS BMD (P < 0.05). CONCLUSIONS: Lower increment in BMD in OWB with higher BMI gain is associated with increasing serum VEGF concentration during pubertal maturation. VEGF, EGF, IL-8, and IFN-γ are significantly associated with BMD during pubertal maturation in boys with different BMI values.

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.

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.

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.

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.

A longitudinal assessment of ghrelin and bone mineral density with advancing pubertal maturation in adolescent female athletes.

AIM: The aim of the present study was to investigate changes in ghrelin and bone mineral density (BMD) during further biological maturation after onset of puberty in female adolescent swimmers. METHODS: Swimmers (n=17) were tested once a year during a two year study period. At the first year, swimmers were at pubertal stages 2 & 3. Fasting plasma ghrelin, leptin, estradiol, insulin-like growth factor-1 (IGF-I) and BMD of the total body, lumbar spine and femoral neck were measured. RESULTS: Ghrelin did not change during the further pubertal development after onset of puberty. No differences in leptin were also seen during the study period. Estradiol and IGF-I were increased during further pubertal development. Total and lumbar spine BMD increased along with further biological maturation. In contrast, further pubertal development had no effect on femoral neck BMD in adolescent female swimmers. Ghrelin was not related to measured BMD values after adjusting for pubertal status at any measurement time. CONCLUSION: Ghrelin concentration did not change with advancing age and pubertal stage after onset of puberty and had no direct influence on bone mineralisation in adolescent female swimmers.

Effect of pubertal development and physical activity on plasma ghrelin concentration in boys.

The aim of the present study was to assess the influence of regular physical activity on plasma ghrelin concentration in pre-pubertal and pubertal boys. In addition, the impact of ghrelin concentration on bone mineral density (BMD) was examined. In total, 56 healthy schoolboys aged between 10 and 16 yr were divided into the swimming (no.=28) and the control (no.=28) groups. The subjects were matched by age and body mass index (BMI), generating 9 matched pairs in pubertal group I (Tanner stage 1), 11 pairs in group II (Tanner stages 2 and 3), and 8 pairs in group III (Tanner stages 4 and 5). Swimmers in pubertal groups II and III had significantly (both p<0.05) higher mean ghrelin levels than the controls (group II: 1126.8+/-406.0 vs 868.3+/-411.2 pg/ml; group III: 1105.5+/-337.5 vs 850.8+/-306.0 pg/ml, respectively), whereas no difference was seen in the pubertal group I (1230.8+/-386.0 vs 1272.7+/-424.4 pg/ml). Ghrelin was the most important hormonal determinant for total BMD and lumbar apparent volumetric BMD (BMAD) (R2=27.2% and R2=19.8%, respectively) in swimmers, whereas in control boys, plasma IGF-I was the most important hormonal predictor accounting for 41.8% of the variability of total BMD and 20.4% of the variability of lumbar BMAD. In conclusion, ghrelin concentration decreased during puberty in physically inactive boys, while in regularly physically active boys it remained relatively unchanged. Ghrelin appears to be an important hormonal predictor for BMD in physically active boys, while BMD is mostly determined by IGF-I in physically inactive boys.

Influence of puberty on ghrelin and BMD in athletes.

The aim of our study was to examine the influence of elevated energy expenditure on ghrelin and BMD in young male competitive swimmers advancing from prepubertal to pubertal maturation levels. The study included 19 healthy swimmers (pubertal stage 1) aged between 10 and 12 years. The participants were at the pubertal stages 2 and 3, and 3 and 4 at the second and third year, respectively. Ghrelin was decreased only after the first year. No changes were observed in leptin during the study period. Testosterone increased according to the pubertal development at each measurements. IGF-I was increased at the third measurement compared to the first two measurements. Total and lumbar spine BMDs increased according to the pubertal development in all boys at each measurements, while no changes in femoral neck BMD were observed. Ghrelin was not related to BMD after adjusting for pubertal status. We conclude that ghrelin was decreased at onset of puberty, while no further changes in ghrelin were seen with advancing pubertal stage. Total and lumbar spine BMD increased, while no changes in femoral neck BMD occurred. Ghrelin did not appear to have a direct influence on BMD in young male competitive swimmers.

Adiponectin and osteocalcin responses to rowing exercise, and the relationship to substrate oxidation in female rowers.

This study investigated the effects of acute exercise and menstrual phase on adiponectin and osteocalcin concentrations, and the possible role of these biomarkers in exercise-induced substrate oxidation in rowers. Thirteen female rowers (19.3 ± 2.3 years; height: 172.7 ± 3.9 cm; body mass: 66.5 ± 7.9 kg) performed 1-h rowing ergometer exercise at 70% of maximal oxygen consumption (VO2max) during follicular phase and luteal phase of the menstrual cycle. Oxygen consumption (VO2), total energy expenditure (EE), carbohydrate EE, and lipid EE were assessed during the exercise. Venous blood samples were collected before and after ergometer exercise. No differences (p > 0.05) were observed in substrate oxidation values during exercise across menstrual cycle. Exercise resulted in an acute rise in osteocalcin and no changes in adiponectin at both menstrual cycle phases. Adiponectin and osteocalcin were not related across phase or time (r < 0.211; p > 0.05). Post-exercise adiponectin was related (p < 0.05) to mean VO2 (r = 0.459) and total EE rate (r = 0.598), while post-exercise osteocalcin was correlated (p < 0.05) with mean total (r = 0.411) and lipid (r = 0.557) EE rates. In conclusion, menstrual cycle phase had no effect on substrate oxidation, and adiponectin and osteocalcin responses to acute exercise. It appears that adiponectin and osteocalcin may serve as signals for metabolic reaction to the energy cost of the acute exercise in female 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.

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.

Relationships between finger-length ratios, ghrelin, leptin, IGF axis, and sex steroids in young male and female swimmers.

The aim of this study was to investigate possible relationships between different right-hand finger-length ratios and different fasting hormone concentrations in young swimmers. Fifty-five young swimmers participated in this study (26 boys and 29 girls, aged 10-17 years). The original method of Visnapuu and Jürimäe (J Strength Cond Res 21:923-929, 2007) was used for the measurement of length parameters of the hand. The following finger-length ratios were calculated: 1D:2D, 1D:3D, 1D:4D, 1D:5D, 2D:3D, 2D:4D, 2D:5D, 3D:4D, 3D:5D, and 4D:5D. All finger-length ratios were significantly higher in girls compared with boys. Ghrelin, leptin, testosterone in boys, estradiol in girls, insulin-like growth-factor I (IGF-I), IGFBP-3, and insulin were analyzed. Leptin and insulin concentrations were lower in boys compared with girls. In both groups, the relationships between finger-length ratios and basic anthropometric parameters were not significant. In girls, estradiol correlated negatively with 2D:3D (r = -0.51) and 2D:4D (r = -0.49) finger ratios. In boys, ghrelin concentration correlated with most of the finger-length ratios (r = 0.37-0.40). In girls, the relationship of ghrelin with the 2D:3D (r = 0.45) and 2D:4D (r = 0.48) finger ratios was significant. In boys, but not in girls, IGF-I (r = 0.42) and IGFBP-3 (r = 0.44) correlated only with the 2D:4D finger ratio. Leptin and insulin did not correlate with the finger-length ratios. In boys, the most important hormone to characterize several finger-length ratios was ghrelin (13.7-15.6% variance accounted for). Ghrelin and testosterone together accounted for 20.3% (R (2) x 100) of the variance in the 2D:4D ratio. In girls, estradiol was correlated with the 2D:3D ratio (25.7%) and estradiol in combination with ghrelin with the 2D:4D ratio (30.0%). In conclusion, ghrelin appears to be a further biochemical parameter in addition to the sex steroids which correlated with different digit-length ratios at least in boys.

Effect of prolonged training period on plasma adiponectin in elite male rowers.

Adiponectin is secreted by adipocytes and has been implicated in the regulation of energy homeostasis. Vigorous training program represents a physical stress condition in which heavy changes in energy expenditure might increase adiponectin concentration in athletes. Therefore, the aim of the present study was to investigate if there are changes in fasting adiponectin concentration during preparatory period in elite male rowers. Twelve rowers (mean and SD; age: 20.8+/-3.0 years; height: 192.9+/-4.7 cm; body mass: 91.9+/-5.3 kg; body fat percentage: 11.9+/-1.4%) were tested seven times over a 24-week training season. In addition to adiponectin, leptin, insulin, growth hormone, and glucose values were evaluated. Maximal oxygen consumption (VO (2 max)) and aerobic power (Pa (max)) were determined before and after the training period. Training was mainly organized as low-intensity prolonged training. Significant increases in VO (2 max) (by 3.2+/-1.8%; from 6.2+/-0.5 to 6.4+/-0.4 l/min), VO (2 max/kg) (by 2.2+/-2.0%; from 67.9+/-3.0 to 69.4+/-3.0 ml/min/kg) and Pa (max) (by 4.6+/-6.3%; from 444.6+/-39.1 to 465.8+/-25.0 W) were observed after the 24-week period. All measured body compositional values were similar to pretraining values after the training period. Fasting adiponectin did not change during the preparatory period. Likewise, leptin, insulin, growth hormone, and glucose values were not significantly changed after the training period. Adiponectin concentration was significantly correlated (all p<0.05) with body mass (r=-0.40), body fat mass (r=-0.33), body fat free mass (r=0.38), and leptin (r=-0.31) values. In conclusion, fasting adiponectin does not change throughout the prolonged training period in elite male rowers despite substantial changes in training volume. Further studies are needed to clarify possible mechanisms by which adiponectin might influence energy homeostasis during heavy training in elite athletes.

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.

Hormonal and psychological adaptation in elite male rowers during prolonged training.

In this study, we examined possible hormonal and psychological changes in elite male rowers during a 24-week preparatory period. Eleven elite male rowers were tested on seven occasions over the 6-month training season. Fasting testosterone, growth hormone, cortisol, and creatine kinase activity, together with perceived recovery-stress state were evaluated after a day of rest. Maximal oxygen consumption (VO2max) was determined before and after the training period. Training was mainly organized as low-intensity prolonged training sessions. Significant increases in VO2max (from 6.2 +/- 0.5 to 6.4 +/- 0.6 l x min(-1)) were observed as a result of training. The overall perceived recovery-stress index did not change during the preparatory period. Standardized recovery and stress scores changed during the course of training in comparison with pre-training values. When basal hormone concentrations were compared with the first measurement, significant changes in testosterone and cortisol were observed together with changes in mean weekly training volume. Basal testosterone (r = 0.416; P = 0.010) and cortisol (r = 0.527; P = 0.001) were related to mean weekly training volume. Basal growth hormone did not change during the training. Changes in creatine kinase activity demonstrated similar pattern with changes in mean weekly training volume. The overall perceived recovery-stress index was related to testosterone, cortisol, growth hormone, and creatine kinase activity (r > 0.299; P < 0.015). Our findings indicate that testosterone and cortisol are more sensitive to changes in training volume than either growth hormone or perceived recovery-stress state in elite rowing training. Increases in these stress hormone concentrations represent a positive adaptation to current training load. Significant relationships between hormonal and perceived recovery-stress state suggest that metabolic and psychological changes should be carefully monitored to avoid a negative effect on the training status of elite rowers.

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.

Plasma testosterone and cortisol responses to prolonged sculling in male competitive rowers.

In this study, we examined anabolic and catabolic hormone responses to a single endurance rowing training session in 12 male competitive single scull rowers. A work intensity eliciting a blood lactate concentration of 4 mmol(-1) was determined on a rowing ergometer during an endurance rowing training session lasting about 2 h (7891+/-761 s; distance covered 22.6+/-2.5 km; heart rate 136+/-7 beats x min(-1); intensity 77.4+/-3.8% of anaerobic threshold; mean +/- s). Venous blood samples were obtained before and after on-water rowing. Cortisol, testosterone and sex hormone binding globulin were measured and free testosterone and the free testosterone: cortisol ratio calculated. Blood lactate concentration did not change significantly during training (from 1.7+/-0.4 to 1.9+/-0.4 mmol x l(-1)); however, body mass was reduced (from 82.0+/-10.8 to 80.6+/-11.2 kg) and was related to the distance covered (r = -0.75). The concentrations of cortisol and testosterone did not change significantly during rowing or in the first 2 h of recovery. Free testosterone was reduced in the first 2 h of recovery, but no significant changes were observed in the free testosterone: cortisol ratio. Immediately after rowing, the concentrations of cortisol (r = 0.49) and free testosterone (r = -0.58) were related to the distance covered. Our findings indicate that a prolonged low-intensity training session results in a similar anabolic and catabolic hormone stimulus for trained rowers.