Upper-body kinematics in team-handball throw, tennis serve, and volleyball spike.

Overarm movements are essential skills in many different sport games; however, the adaptations to different sports are not well understood. The aim of the study was to analyze upper-body kinematics in the team-handball throw, tennis serve, and volleyball spike, and to calculate differences in the proximal-to-distal sequencing and joint movements. Three-dimensional kinematic data were analyzed via the Vicon motion capturing system. The subjects (elite players) were instructed to perform a team-handball jump throw, tennis serve, and volleyball spike with a maximal ball velocity and to hit a specific target. Significant differences (P < 0.05) between the three overarm movements were found in 17 of 24 variables. The order of the proximal-to-distal sequencing was equal in the three analyzed overarm movements. Equal order of the proximal-to-distal sequencing and similar angles in the acceleration phase suggest there is a general motor pattern in overarm movements. However, overarm movements appear to be modifiable in situations such as for throwing or hitting a ball with or without a racket, and due to differences at takeoff (with one or two legs).

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.

[Complications during exercise testing]. / Komplikationen bei der Ergometrie.

Exercise electrocardiogram forms the basis for diagnosis of ischemia in coronary heart disease. Blood pressure behavior, physical fitness, training heart rate and possible cardiac arrhythmias can additionally be assessed using bicycle ergometry or treadmill testing. When the indications for and contraindications to exercise testing (either bicycle ergometry or treadmill testing) are closely observed, serious complications are rare. However, it is important that the treating physician is aware of and able to recognize possible complications. The present article discusses possible cardiovascular complications and their incidence.

Kinematic analysis of volleyball spike jump.

The purpose of this study was to determine the influence of upper and lower extremity movements on the volleyball spike jump (SJ) and how this movement may differ from the standing vertical jumps due to its asymmetry. The 3-D kinematics of body segments were measured in 16 experienced volleyball players with a VICON motion capture system. The jump heights (JH) of counter-movement (CM) and SJ were determined utilizing a force platform. A significant correlation was found between the JH during the SPJ and the maximal horizontal velocity of the center of mass (CoM) (r=0.71, p=0.002), the minimum height of the CoM (r=-0.68, p=0.004), the JH during CMJ (r=0.66, p=0.006) and SJ (r=0.74, p=0.001), the range of movement of right knee flexion-extension (r=0.76, p=0.001) and the angular velocity of left shoulder hyperextension (r=0.72, p=0.002). The asymmetry of the SJ revealed differences in angles, angular velocities of the right and left legs and arms, and a significant difference (p=0.001) between the distances of the left and right foot center to the CoM. Results of our study suggest the importance of optimal approach technique to reach a maximal JH in the volleyball SJ. The SJ movement is influenced by general jumping ability.

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.

Cardiospecificity of the 3rd generation cardiac troponin T assay during and after a 216 km ultra-endurance marathon run in Death Valley.

BACKGROUND: The reasons for the appearance of cardiacspecific troponin (cTnT) after strenuous exercise are unclear. The aim of the present study was to evaluate the cardiospecificity of the 3(rd) generation cardiac cTnT assay during and after an ultra-endurance race of 216 km at extreme environmental conditions in Death Valley. STUDY DESIGN AND METHODS: We measured serially cTnT, creatine kinase (CK), activity and mass of the isoenzyme MB of CK (CK-MB(act) and CK-MB(mass)), and myoglobin in 10 well-trained athletes before, repeatedly during and after the race. RESULTS: Six of 10 participants finished the race within a preset time of 60 hours. Postrace values of biochemical markers CK, CK-MB(act), CKMB(mass), and myoglobin were significantly increased compared to baseline (p<0.05). CK-MB(act) increased from (median (25(th)/ 75(th)percentile) 12 (10/13) U/L to 72 (32/110) U/L, CK-MB(mass) from 3.9 (2.9/5.6) U/L to 65 (18/80) U/L and CK increased from median 136 (98/ 228) U/L to 3,570 (985/6,884) U/L respectively. Pre-race myoglobin was 27 (22/31) microg/l compared to 530 (178/657) microg/l after the run. One runner developed significant exercise-induced rhabdomyolysis with spontaneous recovery. cTnT values remained below the 99(th) percentile reference limit in all athletes including the runner who developed significant rhabdomyolysis (peak CK 27,951 U/L). CONCLUSIONS: Strenuous endurance exercise, even under extreme environmental conditions, does not result in structural myocardial damage in well-trained ultra-endurance athletes. We found no crossreactivity between cTnT and CK, neither in exercise-induced skeletal muscle trauma nor after rhabdomyolysis underscoring the excellent analytical performance of 3(rd) generation cTnT assay.

Oral magnesium therapy, exercise heart rate, exercise tolerance, and myocardial function in coronary artery disease patients.

BACKGROUND: Previous studies have demonstrated that in patients with coronary artery disease (CAD) upward deflection of the heart rate (HR) performance curve can be observed and that this upward deflection and the degree of the deflection are correlated with a diminished stress dependent left ventricular function. Magnesium supplementation improves endothelial function, exercise tolerance, and exercise induced chest pain in patients with CAD. PURPOSE: We studied the effects of oral magnesium therapy on exercise dependent HR as related to exercise tolerance and resting myocardial function in patients with CAD. METHODS: In a double blind controlled trial, 53 male patients with stable CAD were randomised to either oral magnesium 15 mmol twice daily (n = 28, age 61+/-9 years, height 171+/-7 cm, body weight 79+/-10 kg, previous myocardial infarction, n = 7) or placebo (n = 25, age 58+/-10 years, height 172+/-6 cm, body weight 79+/-10 kg, previous myocardial infarction, n = 6) for 6 months. Maximal oxygen uptake (VO2max), the degree and direction of the deflection of the HR performance curve described as factor k<0 (upward deflection), and the left ventricular ejection fraction (LVEF) were the outcomes measured. RESULTS: Magnesium therapy for 6 months significantly increased intracellular magnesium levels (32.7+/-2.5 v 35.6+/-2.1 mEq/l, p<0.001) compared to placebo (33.1+/-3.1.9 v 33.8+/-2.0 mEq/l, NS), VO2max (28.3+/-6.2 v 30.6+/-7.1 ml/kg/min, p<0.001; 29.3+/-5.4 v 29.6+/-5.2 ml/kg/min, NS), factor k (-0.298+/-0.242 v -0.208+/-0.260, p<0.05; -0.269+/-0.336 v -0.272+/-0.335, NS), and LVEF (58+/-11 v 67+/-10%, p<0.001; 55+/-11 v 54+/-12%, NS). CONCLUSION: The present study supports the intake of oral magnesium and its favourable effects on exercise tolerance and left ventricular function during rest and exercise in stable CAD patients.

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.

Off seasonal and pre-seasonal assessment of circulating energy sources during prolonged running at the anaerobic threshold in competitive triathletes.

OBJECTIVES: To compare changes in circulating energy sources during prolonged exercise in off season (OS) and pre-season (PS) training of triathletes. METHODS: Nine athletes of the Swiss national triathlon team (three female, mean (SD) age 28.7 (4.9) years, height 169.8 (6.0) cm, weight 57.0 (6.2) kg, VO(2)max 66.5 (5.3) ml/min/kg; six male, mean (SD) age 24.0 (4.1) years, height 181.4 (6.9) cm, weight 73.5 (6.0) kg, VO(2)max 75.9 (4.9) ml/min/kg) were tested twice (2.5 months apart) during a 25 km aerobic capacity test run at the end of the OS and just before the season. The average training load during the OS was 9.9 h/week, and this increased to 14.4 h/week in the PS. With heart rates as reference, exercise intensity during the aerobic capacity test was 97.0 (4.9)% of the anaerobic threshold and 91.2 (4.5)% of VO(2)max. Blood samples were collected before, during, and after the aerobic capacity test. Samples were collected every 5 km during three minute rest intervals. RESULTS: Blood was analysed for triglyceride (TG), free fatty acids, cholesterol, high density lipoprotein cholesterol, glucose, insulin, lactate, and changes in plasma volume. A two factor (season by distance) repeated measures analysis of variance revealed an increase in capacity for prolonged exercise in the PS by a decrease in running intensity during the aerobic capacity test (% of speed at 2.0 mmol/l lactate threshold, p = 0.008), an increase in running speed at the anaerobic threshold (p = 0.003) and at 4.0 and 2.0 mmol/l (p<0.001) of the lactate threshold. A significant season by distance interaction was found for TG (p<0.001). TG concentrations peaked at 5 km and decreased logarithmically throughout the OS (1.48 (0.34) to 0.86 (0.20) mmol/l) and PS (1.90 (0.31) to 0.73 (0.18) mmol/l) tests. From the OS to the PS, there was an increase in the difference in TG at 5-15 km with a concomitant increase at 2.0 mmol/l of the lactate threshold. The peak TG concentrations at 5 km followed by a logarithmic decrease suggest that TG may also provide circulating energy. A greater logarithmic decrease in TG occurred in the PS than in the OS, indicating a higher rate of use. There was an increase in the difference in TG at 5-15 km similar to the increase in the speed at 2.0 mmol/l of the lactate threshold between the two seasons. Glucose, insulin, lactate, and free fatty acids were similar in the two seasons. CONCLUSION: Free fatty acid and TG concentrations were much higher than expected, and the two training seasons showed significantly different patterns of TG concentration during prolonged running. These responses may be related to aerobic capacity of prolonged exercise.

Validation of a field test for the non-invasive determination of badminton specific aerobic performance.

AIM: To develop a badminton specific test to determine on court aerobic and anaerobic performance. METHOD: The test was evaluated by using a lactate steady state test. Seventeen male competitive badminton players (mean (SD) age 26 (8) years, weight 74 (10) kg, height 179 (7) cm) performed an incremental field test on the badminton court to assess the heart rate turn point (HRTP) and the individual physical working capacity (PWC(i)) at 90% of measured maximal heart rate (HR(max)). All subjects performed a 20 minute steady state test at a workload just below the PWC(i). RESULTS: Significant correlations (p<0.05) for Pearson's product moment coefficient were found between the two methods for HR (r = 0.78) and velocity (r = 0.93). The HR at the PWC(i) (176 (5.5) beats/min) was significantly lower than the HRTP (179 (5.5) beats/min), but no significant difference was found for velocity (1.44 (0.3) m/s, 1.38 (0.4) m/s). The constant exercise test showed steady state conditions for both HR (175 (9) beats/min) and blood lactate concentration (3.1 (1.2) mmol/l). CONCLUSION: The data indicate that a valid determination of specific aerobic and anaerobic exercise performance for the sport of badminton is possible without HRTP determination.

Tracking of serum lipids and lipoproteins from childhood to dyslipidemia in adults: the Bogalusa Heart Study.

Our data demonstrate that serum lipid and lipoprotein levels continue to track from childhood into young adulthood. The persistence and clustering of multiple CVD risk factors from childhood to adulthood and the impact of obesity in this regard point to the need for preventive measures aimed at developing healthy lifestyles early in life. Adverse levels of LDL-C in childhood persist over time, progress to adult dyslipidemias, and relate to obesity and hypertension as well. NCEP guidelines which classify CVD risk on the basis of LDL-C level, are helpful in targeting individuals at risk early in life.

%HRmax target heart rate is dependent on heart rate performance curve deflection.

UNLABELLED: The percent of maximal heart rate (%HRmax) model is widely used to determine training intensities in healthy subjects and patients when prescribing training intensities in these groups of subjects. PURPOSE: The aim of the study was to investigate the influence of the time course of the heart rate performance curve (HRPC) on the accuracy of target training heart rate. METHODS: Sixty-two young healthy male subjects performed an incremental cycle ergometer exercise test until voluntary exhaustion. Subjects were then divided into four groups according to the time course of the HRPC. Groups were classified in regular HR response (kHR2 > 0.2), indifferent HR response (0 < kHR2 < 0.2), linear HR response (kHR2 = 0), and inverted HR response (kHR2 < 0). The first and the second lactate turn point (LTP1, LTP2) as well as the heart rate turn point (HRTP) were determined as submaximal markers of performance. Linear regression lines were calculated for HR in the three regions of energy supply defined by LTP1 and LTP2. RESULTS: HR at LTP1 and HRmax was not significantly different between all four groups. HR at LTP2 was dependent on the time course of the HRPC and was significantly lower (P < 0.05) as kHR2 decreased. Power output and blood lactate concentration at LTP1, LTP2 and maximal workload (Pmax) were not significantly different between the groups. CONCLUSION: From our data, we conclude that target training HR detected by means of the %HRmax method may be overestimated in cases where the HR response is not regular, as it was found in many of our subjects.

Treadmill and cycle ergometry testing in 5- to 6-year-old children.

The primary purpose of this study was to determine the maximal cardiorespiratory responses of 48, 5- to 6-year-old children (24 girls and 24 boys), who were tested on a treadmill (TM) and an electronically braked cycle ergometer (CE). We also examined the percentage of boys and girls who were able to achieve the criteria for reaching maximal oxygen consumption (VO2max) on each testing mode. After an orientation period, each child was tested twice (once on the TM and once on the CE), with an interval of 1 week between tests. VO2max was measured during progressive, all out, continuous TM and CE tests using standardized procedures. A 2 x 2 analysis of variance test (genderxexercise mode) with Bonferroni adjustment revealed the following: (1) there were no gender differences in any of the measured dependent variables, (2) the children produced a significantly higher relative VO2max (ml x kg(-1) x min(-1) and a higher absolute VO2max (l x min(-1)) on the TM than on the CE (P < 0.001), (3) the children produced a higher heart rate on the TM than on the CE (P < 0.001), (4) the CE generated significantly higher values for respiratory exchange ratio (P < 0.001), (5) the criteria necessary to establish a maximal exercise effort were achieved on both the TM and the CE, and (6) all of the children reached two of the criteria associated with a maximal effort, while only 46% of the children reached three criterion measures. There were no significant differences in the attainment of criterion measures between the TM and the CE. The results of this study indicate a lack of gender differences in maximal exercise testing in 5- to 6-year-old children, and that both the CE and the TM are effective modes of maximal cardiorespiratory testing in this age group.

Competition performance and basal nocturnal catecholamine excretion in cross-country skiers.

UNLABELLED: Objective techniques to determine whether an athlete is optimally prepared for a competition are virtually nonexistent. Preparedness for sports competition is commonly judged through the experience of the athletes and their coaches. Evidence from overtraining studies suggests that catecholamine (Cat) excretion rates may correlate with performance in athletes. PURPOSE: We therefore attempted to determine whether a relationship existed between performances of world-class cross-country skiers and basal nocturnal Cat excretion (BNCE). METHOD: During the Cross-Country Skiing World Championships, we determined BNCE in nine cross-country skiers of the Swiss national team by measuring free Cat concentration (dopamine = D, norepinephrine = NE, epinephrine = E) in morning urine samples, using high performance liquid chromatography. Expert judgments of competition performance (ECP) were assessed by two experienced professional coaches of the national team by using an 11-step scale. RESULTS: The BNCE correlated significantly with ECP in cross-country skiers (r2 = 0.84 and P < for NE; r2 = 0.86 and P < 0.001 for D). Athletes who had their best absolute competition results (ACR) showed the highest NE and D concentrations. CONCLUSION: These data suggest that competitive cross-country skiers with higher D and NE excretion may reach better competition levels compared with those with lower levels. Measures of BNCE provide objective information about competition performance, which may benefit athletes in their precompetition preparation.

A physiological profile of tennis match play.

PURPOSE: The aim of this investigation was to examine physiological demands of single match play in tennis. METHODS: 20 players performed 10 matches of 50 min. Respiratory gas exchange measures (RGEM) and heart rates (HR) were measured using two portable systems. Lactate concentration was determined after each game. The average oxygen uptake (VO2) of 270 games was 29.1 +/- 5.6 mL.kg-1.min-1 (51.1 +/- 10.9% of VO2max). Average VO2 for a game ranged from 10.4 to 47.8 mL.kg-1.min-1 (20.4 and 86.8% of VO2max). Average lactate concentration (LA) was 2.07 +/- 0.9 mmol.L-1 (ranging from 0.7 to 5.2 mmol.L-1). Furthermore, we monitored the duration of rallies (DR), the effective playing time (EPT), and the stroke frequency (SF). The average values of 270 games were DR: 6.4 +/- 4.1 s, EPT: 29.3 +/- 12.1%, SF: 42.6 +/- 9.6 shots.min-1. RESULTS: Multiple regression revealed that the DR was the most promising variable for the determination of VO2 in match play (r = 0.54). The body surface area (BSA) and EPT were also entered into the calculation model. In games of two defensive players, VO2 was significantly higher than in games with at least one offensive player. CONCLUSION: Our results suggest that energy demands of tennis matches are significantly influenced by DR. The highest average VO2 of a game of 47.8 mL.kg-1.min-1 may be regarded as a guide to assess endurance capacity required to sustain high-intensity periods of tennis matches compared with average VO2 of 29.1 mL.kg-1.min-1 for the 270 games. Our results suggest that proper conditioning is advisable especially for players who prefer to play from the baseline.

Change in left atrial and ventricular dimensions during and immediately after exercise.

PURPOSE: The aim of this study was to evaluate differences in the left atrial (LAD), total ventricular end-diastolic (TEDD), end-systolic diameters (TESD), and left ventricular shortening fraction (SF) compared with heart rate (HR) and systolic blood pressure (SBP) during exercise and recovery. METHODS: Healthy young male (N = 15) and female (N = 16) subjects performed an incremental cycle ergometer test in upright position, and three phases of energy supply were defined by means of blood lactate concentration (LA) and respiratory gas exchange variables (I: aerobic; II: aerobic-anaerobic transition; III: anaerobic). Subjects were required to rest their arms on a steering bar and to lean their upper body forward; two dimensional (2-D) echocardiograms were obtained over the left parasternal area at rest (R), at the end of each phase, immediately within 15 s post, and 6 min after exercise (6 min). By using VINGMED's "Anatomical M-Mode," it was possible to extract M-Mode Sweeps from stored 2-D-Loops and perform the M-Mode measurement. RESULTS: In contrast to the significant decrease in TEDD and TESD from III to 15 s up to resting values and the significant increase in SF from III to 15 s, the moderate decrease in HR immediately post exercise (15 s) was not significant. The SBP showed a significantly decrease from III to 15 s; in contrast to TEDD, TESD, and SF, the values at 15 s were comparable with the values at II. For LAD, significant increase during exercise and a decrease during recovery were observed. Sex-specific differences of changes in measured variables could not be found. CONCLUSION: We concluded that post exercise measurement of left ventricular and atrial dimensions or SF were not valid to describe heart function at maximal exercise although immediately post exercise HR was near maximal level.

Lipid and lipoprotein profiles, cardiovascular fitness, body composition, and diet during and after resistance, aerobic and combination training in young women.

The purpose of this study was to evaluate the effects of various modes of training on the time-course of changes in lipoprotein-lipid profiles in the blood, cardiovascular fitness, and body composition after 16 weeks of training and 6 weeks of detraining in young women. A group of 48 sedentary but healthy women [mean age 20.4 (SD 1) years] were matched and randomly placed into a control group (CG, n = 12), an aerobic training group (ATG, n = 12), a resistance training group (RTG, n = 12), or a cross-training group that combined both aerobic and resistance training (XTG, n = 12). The ATG, RTG and XTG trained for 16 weeks and were monitored for changes in blood concentrations of lipoprotein-lipids, cardiovascular fitness, body composition, and dietary composition throughout a 16 week period of training and 6 weeks of detraining. The ATG significantly reduced blood concentrations of triglycerides (TRI) (P < 0.05) and significantly increased blood concentrations of high-density lipoprotein-cholesterol (HDL-C) after 16 weeks of training. The correlation between percentage fat and HDL-C was 0.63 (P < 0.05), which explained 40% of the variation in HDL-C, while the correlation between maximal oxygen uptake (VO2max) and HDL-C was 0.48 (P < 0.05), which explained 23% of the variation in HDL-C. The ATG increased VO2max by 25% (P < 0.001) and decreased percentage body fat by 13% (P < 0.05) after 16 weeks. Each of the alterations in the ATG had disappeared after the 6 week detraining period. The concentration of total cholesterol (TC), TRI, HDL-C and low density lipoprotein-cholesterol in the blood did not change during the study in RTG, XTG and CG. The RTG increased upper and lower body strength by 29% (P < 0.001) and 38%, respectively. The 6 week detraining strength values obtained in RTG were significantly greater than those obtained at baseline. The XTG increased upper and lower body strength by 19% (P < 0.01) and 25% (P < 0.001), respectively. The 6 week detraining strength values obtained in XTG were significantly greater than those obtained at baseline. The RTG, XTG and CG did not demonstrate any significant changes in either VO2max, or body composition during the training and detraining periods. The results of this study suggest that aerobic-type exercise improves lipoprotein-lipid profiles, cardiorespiratory fitness and body composition in healthy, young women, while resistance training significantly improved upper and lower body strength only.

Effects of exercise on plasma high-density lipoprotein cholesteryl ester metabolism in male and female miniature swine.

We studied the effects of exercise on high-density lipoprotein (HDL) cholesteryl ester (CE) metabolism in 6 male and 6 female miniature pigs fed a commercial swine diet supplemented with cholesterol and fat. The diets were fed for a total period of 20 weeks. During the last 12 weeks of the feeding period, the pigs were exercised on a motorized treadmill 5 days per week for 45 min/d at a speed of 9.5 to 10.0 km/h at 0% grade. Homologous HDL preparations were radiolabeled with cholesteryl (1-14C)oleate and intravenously administered to the pigs, followed by blood sampling at the appropriate time points and measurement of radiolabeled HDL CE. This was performed while the animals were sedentary and after the exercise period. Plasma cholesterol increased after the exercise protocol from 7.21 +/- 1.90 to 8.50 +/- 2.81 mmol/L (mean +/- SD, n = 6) in the females and from 8.11 +/- 3.61 to 10.07 +/- 3.61 in the males. HDL CE transport rates in female pigs were significantly lower (23%) after the exercise protocol (118 +/- 14 v 91 +/- 14 micromol/h/L plasma). HDL CE transport rates in the males were also lower (11%) after exercise (90 +/- 20 v 80 +/- 18 micromol/h/L plasma), but this effect was not statistically significant. Further, the residence time or life span of HDL CE was significantly longer after the exercise protocol in both male and female pigs. Thus, the results of this study suggest that exercise reduces the transport rate of HDL CE and prolongs the life span of HDL CE in hypercholesterolemic pigs.

Comparison of laboratory and "on-court" endurance testing in tennis.

Treadmill testing (TT) commonly used in endurance testing is often not sport-specific. Therefore a field test (FT) for tennis players was developed. The purpose was 1) to compare metabolic and cardiorespiratory response between TT and FT and 2) to assess tennis stroke ratings during FT. In both tests ventilatory variables (VO2, VE, VT, Bf, VE x VO2(-1)), heart rate (HR), and lactate (LA) were measured. For both tests an "individual anaerobic threshold" (IAT) was calculated. The comparison of TT and FT yielded significant differences in cardiorespiratory and metabolic response. LA and VE were significantly higher in TT compared to FT at VO2 of 35, 40, and 45 ml x kg(-1) x min(-1). There were statistical differences between IAT resulting from both tests (TT vs. FT): HR (165+/-16, 175+/-11, p<0.001), VO2 (44.4+/-4.3, 47.8+/-4.8, p<0.05), LA (3.1+/-0.5, 2.5+/-0.4, p < 0.001), VE (97.0+/-15.6, 89.1+/-14.9, p < 0.05), VT (2.66+/-0.34, 2.34+/-0.47, p<0.05), VE/VO2 (27.9+/-3.9, 23.9+/-2.9, p<0.01). High correlation was found between stroke ratings and the national ranking of the players. We concluded that 1) metabolic, ventilatory, and cardiorespiratory demands of TT vs. FT were (semi)sport-specific and significantly different and 2) that the stroke rating in our study was a good predictor for tournament performance (r = 0.94). This type of stroke rating can be implemented in a FT.