Effect of heavy increase in training stress on the plasma leptin concentration in highly trained male rowers

AIM: To characterize the effects of a heavy increase in training stress followed by a reduced stress on fasting plasma leptin levels in highly trained male rowers. METHODS: 12 rowers underwent a 3-week period of maximally increased training stress followed by a 2-week tapering period. RESULTS: A mean 22% increase in training stress caused a significant decrease (by 8%) in the leptin concentrations. A further increase in training stress by 25% significantly reduced leptin further by 35%. A 1st tapering week, during which the training stress was rapidly reduced by approximately 50%, significantly increased the plasma leptin concentrations by 29%. Plasma leptin was significantly increased further (by 4%) during the 2nd tapering week. CONCLUSION: Leptin is sensitive to pronounced changes in training stress in highly trained male rowers.     

Plasma ghrelin is altered after maximal exercise in elite male rowers

The aim of the present investigation was to investigate plasma ghrelin response to acute maximal exercise in elite male rowers. Eight elite male rowers performed a maximal 6000-m rowing ergometer test (mean performance time: 19 mins 52 secs; 1192.1 +/- 16.4 secs), and venous blood samples were obtained before, immediately after, and after 30 mins of recovery. In addition to ghrelin concentration, leptin, insulin, growth hormone, insulin-like growth factor-1 (IGF-1), testosterone, cortisol, and glucose values were measured. Ghrelin was significantly increased immediately after the exercise (+24.4%; P < 0.05) and was not significantly different than baseline after 30 mins of recovery. Leptin was significantly decreased immediately after the exercise (- 15.8%; P < 0.05) and remained significantly decreased after the first 30 mins of recovery. No changes occurred in insulin concentrations. Growth hormone, IGF-1, and testosterone values were significantly increased and decreased to the pre-exercise level immediately after the exercise and after the first 30 mins of recovery, respectively. Cortisol and glucose values were significantly increased immediately after the exercise and remained significantly increased during the first 30 mins of recovery. There were no relationships between plasma ghrelin and other measured blood parameters after the exercise, nor were changes in ghrelin related to changes in other measured blood biochemical values after the exercise. In conclusion, these results suggest that acute negative energy balance induced by specific maximal short-term exercise elicits a metabolic response with opposite changes in ghrelin and leptin concentrations in elite male athletes.     

Long-term training adaptations in elite male volleyball players

Several investigations have demonstrated differences in anthropometry, jump performance, and strength variables between developmental and elite-level volleyball players. However, within the elite level of play, the magnitude of change that can occur with training is unclear. The purpose of this investigation was to examine the anthropometric, vertical jump, and strength quality changes over 2 years in a group of national team volleyball players. Fourteen national team volleyball players (age, 23.0 ± 4.1 years; height, 1.98 ± 0.07 m; weight, 91.7 ± 7.9 kg) began and completed this study. Participants had all played international matches (representing Australia) before the examination time period and continued to do so during the international season. Anthropometry (stature, mass, and sum of 7 skinfolds), vertical jump measures (countermovement vertical jump; depth jump from 0.35 m, DJ; spike jump, SPJ, all including arm swing), and lower-body power (jump squat at body mass, and jump squat + 50% body weight, JS50) measures were tested before and at the conclusion of the investigation period. Significant (p < 0.05) improvements were observed in sum of 7 skinfolds, DJ, SPJ, and JS50 performance, with large magnitude changes (d > 0.70) in the sum of 7 skinfolds reduction, SPJ, and leg extensor power. This study has demonstrated that elite male volleyball players can improve leanness and power, which contribute to improvements in vertical jump.     

Exercise training intensity/volume affects plasma and tissue adiponectin concentrations in the male rat

The objective of the study was to determine the effects of exercise training intensity/volume on plasma total and high molecular weight (HMW) adiponectin and tissue total adiponectin concentrations. Thirty-two, eight week-old male Wistar rats (185 ± 5 g) were randomly assigned to one of four groups: high intensity (HI: 34 m/min ∼%80-%85 VO₂max), moderate intensity (MI: 28 m/min ∼%70-%75 VO₂max), low intensity (LI: 20m/min ∼ %50-%55 VO₂max), and sedentary control (SED). Experimental groups completed a 12-week exercise program of treadmill running at 0° slope, 1 h/day, 5 days/week. Since frequency and duration of exercise were identical among training groups, the volume of training was highest in the HI group followed by the MI and LI groups. Compared with SED animals, fasting plasma total and HMW adiponectin and adipose tissue total adiponectin concentrations were significantly higher in the HI and MI groups, but total adiponectin concentrations in liver and soleus muscle were not significantly lower than the SED rats. There were significantly lower plasma total testosterone levels in the HI group vs. SED group. Plasma total and HMW adiponectin were negatively correlated with HOMA-IR and insulin whereas total adiponectin was inversely related to TNF-α and HMW adiponectin was negatively correlated with total testosterone. Thus, data suggest there is a dose effect for exercise training intensity and accompanying volume for the adaptation of adipose tissue and circulating total and HMW adiponectin concentrations, whereas the changes of adiponectin concentrations in skeletal muscle and liver tissue may depend on the body's energy balance in the recovery 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.     

Serum hormone concentrations during prolonged training in elite endurance-trained and strength-trained athletes

A study of 1 year was performed on nine elite endurance-trained athletes (swimmers) and on eight elite strength-trained athletes (weightlifters) in order to examine the effects of training on the endocrine responses and on physical performance capacity. The measurements for the determination of serum hormone concentrations were performed at about 4-month intervals during the course of the year. The primary findings demonstrated that during the first and most intensive training period of the year in preparing for the primary competitions similar but statistically insignificant changes were observed in the concentrations of serum testosterone, free testosterone and cortisol in both the endurance-trained and strength-trained groups. After that period the changes in hormonal response over the year were infrequent and minor. A significant (p less than 0.01) decrease occurred in the strength-trained group in serum-free testosterone during the second period, which was characterized by the highest overall amount of training. Over the entire year the concentrations of serum hormones remained statistically unaltered in both groups. Slight but statistically insignificant increases of 1.2% +/- 0.8% and 2.1% +/- 5.1% were observed in the competitive performances over the year in the endurance-trained and strength-trained groups, respectively. The present findings in the two groups of elite athletes, who differed greatly with regard to the type of physiological loading, demonstrated that the overall hormonal responses both during the most intensive and during prolonged training periods were rather similar and the infrequent small changes remained well within the normal physiological range.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of the period of resting in elite judo athletes

The purpose of this study was to evaluate the effect of the resting period on hematological and copper-zinc-dependent antioxidant indices in Brazilian elite judo athletes (n=7). Venous blood samples were collected after 24-h and 5-d periods of resting following a competition, with an interval of 30 d between collections. Two months prior to and during the study, each athlete received an individualized adequate diet. Body composition was determined at both study periods. The following were analyzed: in whole blood, hemoglobin, hematocrit, red cell count, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red cell distribution width, and white cell count; in plasma, zinc, copper, iron, ceruloplasmin, and total iron-binding capacity; in erythrocytes, metallothionein, copper/zinc superoxide dismutase, and osmotic fragility. Dietary intake and body composition did not affect the biochemical measurements. A significant reduction in ceruloplasmin and superoxide dismutase activity was found after 5 d compared to 24 h of resting. A significant correlation between erythrocyte metallothionein and red cell distribution width was observed after 24 h of resting (r=−0.83, p=0.02) whereas positive correlations of metallothionein with hemoglobin, red cell count, and mean corpuscular hemoglobin concentration were observed after 5 d of resting (r≥0.76, p≤0.05). Our results suggest that a longer resting period favors homeostatic adjustments in the erythrocyte population and in the copper/zinc-dependent antioxidant system in elite judo athletes.     

Body size changes in elite junior rowers: 1997 to 2007

The aim of this study was to determine whether elite international junior rowers in 2007 were heavier and taller than those evaluated in 1997, and to compare this change among finalists and non-finalists, and sweep rowers and scullers. Body weight and height data obtained by a questionnaire from a total of 398 rowers (42% female, 58% male) at the Junior World Rowing Championships in Beijing, People's Republic of China, in 2007 (65.9% of all competitors), were compared with data from 603 rowers measured at the Junior World Rowing Championships in Hazewinkel, Belgium in 1997 (36.5% female, 63.5% male, representing 90% and 89% of all competitors, respectively, by gender). Male and female rowers in 2007 were significantly taller compared to those in 1997 (1.0 cm, p = 0.009 and 2.1 cm, p < 0.001, respectively; one-sample t-test). No statistically significant difference was found for body mass. The finalists and sweep rowers were taller and heavier compared to nonfinalists and scullers at both Championships respectively. The heights of elite level junior rowers increased significantly over the decade. The finalists at World Junior Rowing Championships were again taller and heavier compared to the nonfinalists.     

The influences of training on rowers of different age

We measured 14 rowers and divided them into two groups according to age and years of training. Our goal has been to establish the influence of several years of programmed training on the structure of the body, oxygen carrying capacity and oxidation capacity of muscle cells, the chemical composition of blood and characteristics of pulse and lactate curves in rowers. As to the structure of the body, the two groups did not differ if we equalised them according to body height. Differences existed in the determinants of oxygen carrying capacity and oxidation capacity of muscle cells. Older rowers had lower pulse at rest, higher step test index, lower pulse immediately after the step test and in the last minute of the test on a bicycle ergometer and higher maximal oxygen pulse. While at rest, no significant differences between the groups were observed in most of the analysed substances in the blood serum. With the increase of age and training period an increase of the concentration of creatinin and activity of creatine kinase and lessening of the activity of alkaline phosphatase was noted. Length of training period lowers the levels of cholesterol and free fatty acids and increases the level of triglycerides in blood serum. An increase of the activity of creatine kinase and lactate dehydrogenase and the formation of a specific pattern of isoenzymes was observed. The pulse and lactate curve flattened and moved to the right.     

Serum cortisol concentration and testosterone to cortisol ratio in elite prepubescent male gymnasts during training.

Serum cortisol concentrations and testosterone:cortisol concentration ratios of eight prepubescent elite male gymnasts (mean age 10 years 11 months) and 11 controls (mean age 11 years 1 month) were examined during 5 consecutive training days. During this period, the gymnasts trained 3 h each day with moderate intensity mobility, strength and skill exercises while the controls were relatively sedentary. Blood samples were taken from all the boys in both groups before (1630 hours) and 30 min after (2000 hours) training on 4 days. Serum cortisol concentrations of the gymnasts were not significantly different from those of the controls throughout the experiment. Serum cortisol concentrations of both groups were significantly larger (P < 0.05) at 1630 hours than at 2000 hours, indicating that cortisol secretion followed the typical adult circadian change, seemingly unaltered by training. However, there was a significant decrease (P < 0.05) in the testosterone:cortisol ratio of the gymnasts when compared with controls from day 1 to day 3. After a rest on day 4 the testosterone: cortisol ratio of the gymnasts significantly increased (P < 0.05) but the ratio of the control group also increased indicating that there may have been some day-to-day change by factor(s) other than training. The most obvious factor which may have accounted for the unresponsiveness of serum cortisol concentration to the gymnastics training was that the exercise intensity was too low. However, several days of the training seemed to reduce the anabolic to catabolic balance but further experiments are needed to confirm this finding.     

Effect of exercise training on adipocyte-size-dependent expression of leptin and adiponectin

AimsOur aim was to evaluate the effect of exercise training (TR) on adipocyte-size-dependent expression of leptin and adiponectin.Main methodsMale Wistar rats were divided into 2 groups, sedentary control (CR) and TR group, and both monitored for 9 weeks. Adipocytes isolated from epididymal, retroperitoneal, and inguinal fat depots were independently separated into 3 fractions of different cell size, and the relationships between adipocyte size and either leptin or adiponectin mRNA were determined by real-time RT-PCR analysis.Key findingsIn epididymal and inguinal adipose tissue, positive relationships between adipocyte size and both leptin and adiponectin mRNA expression were found. Comparison of TR and CR rats showed no significant effect of TR on the slopes of the linear regression lines of correlation between leptin mRNA and adipocyte size in either adipose tissue, whereas the slopes of the regression line of correlation between adipocyte size and adiponectin mRNA were greater in TR group. Leptin levels per milliliter of plasma were significantly lower in TR than CR rats, whereas leptin levels adjusted to the 3 fat depots did not differ. TR did not affect adiponectin levels in plasma, whereas adiponectin levels adjusted to the 3 fat depots were significantly greater in TR than CR group.SignificanceTR-induced reduction in leptin mRNA expression was closely associated with smaller adipocyte size. However, TR amplified the adipocyte-size-dependent expression of adiponectin mRNA, suggesting that TR-induced alterations in adiponectin mRNA may also be mediated by factor(s) other than adipocyte size.     

Effect of prolonged dynamic exercise on plasma adrenomedullin concentration in healthy young men.

The aim of the study was to find out whether prolonged exercise influences plasma adrenomedullin (ADM) concentration and whether it is related to the hormonal, metabolic and cardiovascular changes. Eighteen healthy subjects (age 25+/-1 yrs) were submitted to cycle exercise for 90 min at 70% of maximal oxygen uptake. Heart rate (HR) and blood pressure (BP) were measured continously. Before, at 30(th) min, and at the end of exercise venous blood samples were taken for [ADM], noradrenaline [NA], adrenaline [A], atrial natriuretic peptide [ANP], plasma renin activity PRA, interleukin-6 [IL-6] and lactate [LA] determination. Significant increases in plasma ADM and IL-6 were found at 90(th) min whereas other hormones were elevated already at 30(th) min of exercise. Positive correlations were ascertained between [ADM] and [NA] (r=0.47), [ANP] (r=0.35) or [IL-6] (r=0.35) and between exercise-induced increases in [ADM] and [NA] (r=0.38). PRA correlated positively with [NA] and [ANP]. Negative correlation was found between plasma [ADM] and diastolic BP. The present data suggest that increase in sympathetic nervous activity and cytokine induction during prolonged exercise may be involved in plasma ADM release and that increase in ADM and ANP secretion may be a compensatory mechanism against further elevation of blood pressure.     

Effect of training in Greco-Roman wrestling on neck strength at the elite level

Special training methods in wrestling have been assumed to improve the stability and tolerance of the neck. The aim of this study was to measure the neck strength levels reached in an extremely physically demanding sport. A neck strength measurement system was used to measure various parameters of maximal isometric neck strength in Finnish senior wrestlers competing at the international level. The results were compared with those achieved by junior wrestlers and a control group. The means (SD) of the maximal isometric neck strength for cervical rotation were 0.4 (0.1) Nm.kg(-1) for the senior wrestlers, 0.3 (0.1) Nm.kg(-1) for the junior wrestlers, and 0.2 (0.1) Nm.kg(-1) for the nonsportsmen. The respective results for cervical flexion were 4.4 (1.4), 3.8 (0.7), and 2.3 (0.8) Nm.kg(-1); for extension, 6.0 (1.1), 5.9 (0.7), and 4.0 (0.9) Nm.kg(-1). Neck strength in flexion seems to improve more than in extension as the result of wrestling. The greatest difference was found in rotation, which in the senior wrestlers was almost 3 times that in the nonsportsmen. There was great individual variation within all groups, and the results revealed weaknesses in all directions. Maximal neck strength measurements provide information useful in planning training programs to correct possible muscle deficiency and imbalance.     

"Living high-training low" altitude training improves sea level performance in male and female elite runners.

Acclimatization to moderate high altitude accompanied by training at low altitude (living high-training low) has been shown to improve sea level endurance performance in accomplished, but not elite, runners. Whether elite athletes, who may be closer to the maximal structural and functional adaptive capacity of the respiratory (i.e., oxygen transport from environment to mitochondria) system, may achieve similar performance gains is unclear. To answer this question, we studied 14 elite men and 8 elite women before and after 27 days of living at 2,500 m while performing high-intensity training at 1,250 m. The altitude sojourn began 1 wk after the USA Track and Field National Championships, when the athletes were close to their season's fitness peak. Sea level 3,000-m time trial performance was significantly improved by 1.1% (95% confidence limits 0.3-1.9%). One-third of the athletes achieved personal best times for the distance after the altitude training camp. The improvement in running performance was accompanied by a 3% improvement in maximal oxygen uptake (72.1 +/- 1.5 to 74.4 +/- 1.5 ml x kg(-1) x min(-1)). Circulating erythropoietin levels were near double initial sea level values 20 h after ascent (8.5 +/- 0.5 to 16.2 +/- 1.0 IU/ml). Soluble transferrin receptor levels were significantly elevated on the 19th day at altitude, confirming a stimulation of erythropoiesis (2.1 +/- 0.7 to 2.5 +/- 0.6 microg/ml). Hb concentration measured at sea level increased 1 g/dl over the course of the camp (13.3 +/- 0.2 to 14.3 +/- 0.2 g/dl). We conclude that 4 wk of acclimatization to moderate altitude, accompanied by high-intensity training at low altitude, improves sea level endurance performance even in elite runners. Both the mechanism and magnitude of the effect appear similar to that observed in less accomplished runners, even for athletes who may have achieved near maximal oxygen transport capacity for humans.     

Response of red cell and plasma volume to prolonged training in humans

To clarify the role of progressive heavy training on vascular volumes and hematologic status, seven untrained males [maximal O2 uptake (VO2max) = 45.1 +/- 1.1 (SE) ml.kg-1.min-1] cycled 2 h/day at an estimated 62% of VO2max. Training was conducted five to six times per week for approximately 8 wk. During this time, VO2max increased (P less than 0.05) by 17.2%. Plasma volume (PV) measured by 125I increased (P less than 0.05) from 3,068 +/- 104 ml at 0 wk to 3,490 +/- 126 ml at 4 wk and then plateaued during the remaining four wk (3,362 +/- 113 ml). Red cell (RBC) mass (RCM) measured by 51Cr-labeled RBC did not change during the initial 4 wk of training (2,247 +/- 66 vs. 2,309 +/- 128 ml). As well, no apparent change occurred in RCM during the final 4 wk of training when RCM was estimated using PV and hematocrit (Hct). Collectively, PV plus RCM, expressed as total blood volume (TBV), increased (P less than 0.05) by 10% at 4 wk and then stabilized for the final 4 wk. During the initial phase of training, reductions (P less than 0.05) were also noted in Hct (4.6%), hemoglobin (Hb, 4.0%), and RBC count (6.3%). In contrast, an increase in mean cell volume (MCV, 1.7%) and mean cell Hb (2.3%) was observed (P less than 0.05). From 4 to 8 wk, no further changes (P greater than 0.05) in Hb, RBC, and MCV were found, whereas both mean cell Hb and Hct returned to pretraining levels.(ABSTRACT TRUNCATED AT 250 WORDS)     

Enhanced plasma IL-6 and IL-1ra responses to repeated vs. single bouts of prolonged cycling in elite athletes.

The impact of repeated bouts of exercise on plasma levels of interleukin (IL)-6 and IL-1 receptor antagonist (IL-1ra) was examined. Nine well-trained men participated in four different 24-h trials: Long [two bouts of exercise, at 0800-0915 and afternoon exercise (Ex-A), separated by 6 h]; Short (two bouts, at 1100-1215 and Ex-A, separated by 3 h); One (single bout performed at the same Ex-A as second bout in prior trials); and Rest (no exercise). All exercise bouts were performed on a cycle ergometer at 75% of maximal O(2) uptake and lasted 75 min. Peak IL-6 observed at the end of Ex-A was significantly higher in Short (8.8 +/- 1.3 pg/ml) than One (5.2 +/- 0.7 pg/ml) but not compared with Long (5.9 +/- 1.2 pg/ml). Peak IL-1ra observed 1 h postexercise was significantly higher in Short (1,774 +/- 373 pg/ml) than One (302 +/- 53 pg/ml) but not compared with Long (1,276 +/- 451 pg/ml). We conclude that, when a second bout of endurance exercise is performed after only 3 h of recovery, IL-6 and IL-1ra responses are elevated. This may be linked to muscle glycogen depletion.