Showing papers in "International Journal of Sports Medicine in 1989"
TL;DR: The strategy of intake of large quantities of CHO-rich liquids seems to be the appropriate answer to maintain energy and fluid balance under these extreme conditions.
Abstract: Food intake and energy expenditure (EE) were studied in five cyclists during the 22-day race of the Tour de France. The course is about 4000 km including 30 mountain passages (up to 2700 m altitude) and can be considered as one of the most strenuous endurance endeavors. Nutritional intake was calculated from daily food records. EE was estimated from sleeping time and the low activity period. EE during cycling was predicted based on detailed information. Mean energy intake (EI) was 24.7 MJ with a highest mean daily EI of 32.4 MJ. Mean EE was 25.4 MJ with a highest mean daily EE of 32.7 MJ. Relative contribution of protein, CHO, and fat was 15, 62, and 23 En% resp. 49% of EI was taken during the race resulting in a CHO intake of 94 g.h-1 representing 69 en%. It is questioned whether this amount of CHO is optimal in relation to CHO oxidation and performance. About 30% from CHO intake came from CHO-rich liquids. High EI resulted in high Ca and Fe intake. For vitamins, especially B1, this relation was not found. Vitamin B1 nutrient density dropped to 0.25 mg/4.2 MJ during the race caused by a large intake of refined CHO-rich food items. However, vitamin supplementation was high. Daily water intake was 6.71 with extremes up to 11.81. Therefore, the strategy of intake of large quantities of CHO-rich liquids seems to be the appropriate answer to maintain energy and fluid balance under these extreme conditions.
257 citations
TL;DR: It is suggested that exercise performance and muscle glycogen content are enhanced during the LP of the menstrual cycle, which implies athletic performance may be affected by the phases of the menstruation cycle.
Abstract: Six eumenorrheic females (age = 26.3 +/- 2.4 yrs; X +/- SE) exercised until exhaustion (EE; 70% VO2max) at the midluteal (LP, 7-8 days after ovulation) and midfollicular (FP, days 7-8) phases of their menstrual cycles. Phases were confirmed by estradiol and progesterone concentrations. Each EE test was preceded by a depletion exercise bout (DE; 90 min, 60% VO2max and 4 x 1 min, 100% VO2max) and 3 days of rest/diet control. Muscle biopsies 1% (vastus lateralis) were taken post-DE, pre-EE, and post-EE and then analyzed for glycogen content. There was a strong tendency (P less than 0.07) for EE duration to be greater during LP (139.2 +/- 14.9 min) than FP (126 +/- 17.5 min). Glycogen repletion (pre-EE minus post-DE) following DE was greater (P = 0.05) during the LP than FP (88.2 +/- 4.7 vs 72.8 +/- 5.7 mumol/g w. w. muscle). However, EE glycogen utilization (pre-EE minus post-EE/EE time) did not differ between phases (LP = 0.41 +/- 0.08 mumol/g w. w. muscle/min vs FP = 0.33 +/- 0.11 mumol/g w. w. muscle/min; P = 0.17). The results suggest that exercise performance and muscle glycogen content are enhanced during the LP of the menstrual cycle. These findings imply athletic performance may be affected by the phases of the menstrual cycle.
186 citations
TL;DR: It is concluded that in general there are two major concerns: in those sports in which body composition plays an important role, energy and thus nutrient intake is often marginal and in all groups of athletes intake of carbohydrate is insufficient.
Abstract: Information about habitual food intake was systematically obtained from elite endurance, strength, and team sport athletes. The athletes (n = 419) trained at least 1-2 h daily and competed on an international level. A 4- or 7-day food diary was kept. For analysis of the data, a computerized food table was used. Mean energy intake varied from 12.1-24.7 MJ per day for male and 6.8-12.9 MJ per day for female athletes. Protein intake was in agreement with or higher than the Dutch recommendations. Contribution of carbohydrate intake to total energy intake varied from 40%-63%. Fat intake tended to meet the criteria for a prudent diet (less than 35%). Snacks contributed about 35% to the total energy intake and the bread/cereals and dairy food groups were the most important energy sources. It is concluded that in general there are two major concerns. In those sports in which body composition plays an important role, energy and thus nutrient intake is often marginal. In all groups of athletes intake of carbohydrate is insufficient.
175 citations
TL;DR: There was a significant correlation between the number of injured volunteers and the distance covered during the training at the start of the training program, and the anatomic distribution of the injuries is in agreement with findings in the literature.
Abstract: To study the occurrence of running-related injuries, a group of 115 volunteers were supervised in a training program. These subjects who had limited or no running experience were asked to keep a diary in which they registered information on the training program and injuries. Ultimately, 63% of the diaries fulfilled the criteria for inclusion into longitudinal analysis. The training program (18-20 months) consisted of three phases, each phase finished with a contest (15 km, 25 km, and a marathon, respectively). The participants were individually supervised by an experienced coach with special attention to physiologic training and injury-preventive aspects. Eighty-five percent (n = 62) of the research population sustained at least one injury during the experiment. They reported in total 174 injuries. The number of injury cases per week increased gradually over the experimental period; however, when expressed per unit of exposure time (i.e., 1000 training hours), it showed a decline. There was a significant correlation between the number of injured volunteers and the distance covered during the training at the start of the training program. The anatomic distribution of the injuries is in agreement with findings in the literature. There was also a possible preference for the localization of injuries to the lower leg and Achilles tendon on the left side of the body.
159 citations
139 citations
TL;DR: It was found that calcium and iron intake was positively related to energy intake, and vitamin and mineral intake is sufficient, when energy intake ranges between 10 and 20 MJ/day.
Abstract: The nutritional habits of elite athletes competing at a national and international top level were determined. Groups of endurance strength, and team sport athletes participated. All athletes trained at least 1-2 h daily. The purpose of the study was to quantify the mineral and vitamin intake and to identify the magnitude of the nutrient supplementation use. Information on food intake was obtained by a 4- or 7-day food diary. It was found that calcium and iron intake was positively related to energy intake. In low energy intakes (less than 10 MJ) iron intake might be insufficient. In general, vitamin intake with food was in agreement with the Dutch recommendations. However, if energy intake is high (greater than 20 MJ) the amount of refined carbohydrate is increased. Consequently, the nutrient density for vitamin B1 drops. Therefore, under these conditions, supplementation for vitamin B1 must be considered. The low vitamin intake found in lower energy intakes can be improved by proper nutritional advice. In body building and in professional cycling, high dosages of vitamins are used. The other groups of athletes used only moderate quantities of vitamin supplements. It is concluded that vitamin and mineral intake is sufficient, when energy intake ranges between 10 and 20 MJ/day.
139 citations
TL;DR: The results suggest that exhaustive endurance exercise in marathon runners is associated with many significant perturbations in immune system parameters, most of which return to normal levels at 21 h of recovery.
Abstract: The extent and duration of changes in leukocyte subsets, lymphocyte subpopulations, spontaneous blastogenesis, cortisol, and catecholamines were measured in ten experienced marathoners, who ran 3 h to exhaustion in a laboratory setting. Blood samples were taken at baseline, 1 h of exercise, and 5 min, 1.5 h, 6 h, and 21 h of recovery. The 3-h endurance run was associated with significant leukocytosis, granulocytosis, neutrophilia, monocytosis, and eosinopenia during recovery. All of these parameters except for eosinophils returned to normal by 21 h of recovery. Total lymphocyte count increased 31% at 1 h of exercise, then decreased 19% at 1.5 h of recovery when compared with baseline values. T cell count showed no significant changes, but B cell lymphocytosis was measured at 5 min and 6 h of recovery. T helper/T suppressor ratio (H/S) was significantly elevated 39% at both 1.5 h and 21 h of recovery due to the decrease in number of T suppressor cells. Spontaneous blastogenesis was significantly increased 52% by 1 h of exercise and remained elevated throughout recovery. The increase in cortisol from baseline to 1.5 h of recovery correlated positively with the increase in both total leukocyte count (r = 0.78, P = 0.008) and granulocyte count (r = 0.81, P = 0.005). Our results suggest that exhaustive endurance exercise in marathon runners is associated with many significant perturbations in immune system parameters, most of which return to normal levels at 21 h of recovery.
139 citations
136 citations
TL;DR: The results indicate that the ECC torque-velocity curve is essentially level for both quadriceps and hamstring muscles, pointing strongly toward the necessity of correcting for GET when calculating both CONC and ECC H/Q quotients.
Abstract: The purpose of this study was to assess and compare eccentric (ECC) and concentric (CONC) torque output of the quadriceps and hamstring muscles and to analyze the effect of gravity effect torque (GET) correction on the calculation of the hamstring/quadriceps peak torque quotient (H/Q quotient). Twenty female subjects performed maximal voluntary CONC and ECC contractions of the quadriceps and hamstring muscles at five isokinetic lever arm velocities from 60 degrees/s to 360 degrees/s. Peak torque was measured and corrected for GET. Mean ECC torque did not significantly change with increasing ECC velocity for either the quadriceps or hamstring muscles (P greater than 0.05). Mean CONC torques were significantly lower than the corresponding ECC torques (P less than 0.05) and decreased with increasing CONC velocity. At each test velocity, the CONC H/Q quotient was significantly lower than the corresponding ECC H/Q quotient (P less than 0.05). Mean H/Q quotients did not significantly change with increasing velocity for either the CONC or ECC tests (means: 0.46 and 0.57; P greater than 0.05). Mean H/Q quotients not corrected for GET significantly increased with increasing velocity for the CONC (0.61 to 0.78; P less than 0.05), but not ECC tests (0.66 to 0.71; P greater than 0.05). The results indicate that the ECC torque-velocity curve is essentially level for both quadriceps and hamstring muscles. The present findings point strongly toward the necessity of correcting for GET when calculating both CONC and ECC H/Q quotients.(ABSTRACT TRUNCATED AT 250 WORDS)
126 citations
TL;DR: Exercise training, especially for those at risk for heart diseases is beneficial to the lipid profile of women, as shown in the results of this analysis.
Abstract: It has been suggested that regular exercise produces favorable changes in serum lipid and lipoprotein-cholesterol concentrations. However, most of the subjects in this area of research have been men. Given the differences in lipid profiles between men and women, we wanted to determine if these same favorable changes took place in women. Of the 145 longitudinal studies available in this area, 27 met the criteria for inclusion in this analysis (i.e., an exercise training study that used women subjects and measured changes in lipid concentrations). Results show that exercise does favorably alter serum lipid profiles in women by reducing total cholesterol (194 to 190 mg.dl-1; P = 0.02), triglyceride (91 to 82 mg.dl-1; P = 0.01), and the ratio of total cholesterol to high-density lipoprotein-cholesterol (3.28 to 3.16; mg.dl-1; P = 0.03). However, a significant increase in high-density lipoprotein-cholesterol or decrease in low-density lipoprotein-cholesterol concentration was not observed. Results also show that changes in body weight during exercise are associated with changes in total cholesterol (r = 0.56; P = 0.01) and triglyceride (r = 0.42; P = 0.06) concentrations, indicating that greater body weight losses resulted in larger decreases in cholesterol and triglyceride concentrations. Further analysis indicates that those women most at risk for heart disease (elevated pre-exercise cholesterol concentrations) responded most favorably to exercise training. These results suggest that exercise training, especially for those at risk for heart diseases is beneficial to the lipid profile of women.
123 citations
TL;DR: The increase of elastase-alpha 1-antitrypsin, neopterin, tumor necrosis factor, and soluble interleukin-2 receptor supports the concept of a functional involvement of polymorphonuclear neutrophils and an activation of macrophages and T-lymphocytes after prolonged exercise.
Abstract: The effects of a 2.5-h running test on the plasma concentrations of elastase-alpha 1-antitrypsin, neopterin, tumor necrosis factor, and soluble interleukin-2 receptor were evaluated in eight healthy young male subjects. Neopterin was measured by radioimmunoassay, elastase-alpha 1-antitrypsin, tumor necrosis factor, and soluble interleukin-2 receptor by enzyme immunoassay. The post-exercise values were corrected for plasma volume changes which were calculated from hematocrit and hemoglobin values. Compared with the concentrations before exercise, elastase-alpha 1-antitrypsin values were significantly increased during the run (1 h after the start) (P less than 0.01) as well as during the first few hours after the end of the running test (P less than 0.01). A significant increase of tumor necrosis factor and neopterin was observed 1 h after the end and 1,3, and 24 h after the end of the running test, respectively, (P less than 0.01), and soluble interleukin-2 receptor concentrations were significantly elevated 1 and 2 days after exercise (P less than 0.01). The increase of elastase-alpha 1-antitrypsin, neopterin, tumor necrosis factor, and soluble interleukin-2 receptor supports the concept of a functional involvement of polymorphonuclear neutrophils and an activation of macrophages and T-lymphocytes after prolonged exercise.
TL;DR: The increased NK cell function thus demonstrated in highly trained persons might result in better resistance against infectious disease.
Abstract: Natural killer (NK) cell activity and concentration of CD16+ cells (NK cells) and CD20+ cells (monocytes) in peripheral blood were measured in highly trained racing cyclists and in age- and sex-matched untrained controls. Median NK cell activity was 38.1% (range 20.0%-57.1%) in trained vs 30.3% (range 19.7%-43.1%) in untrained (P = 0.008). Median %CD16+ cells was 17% (range 7%-33%) in trained vs 11% (3%-29%) in untrained (P = 0.007). Indomethacin in vitro enhanced the NK cell activity in both groups. There was, however, no significant difference between the NK cell activity in trained and untrained after exposure to indomethacin in vitro. Indomethacin-enhanced NK cell activity was 45.9% (range 24.4%-67.5%) in trained and 40.0% (range 23.9%-68.5%) in untrained (P = 0.138). Mean %CD14+ cells was 8.3% (range 2%-15%) in trained vs 3.8% (2%-8%) in untrained (P less than 0.0001). The increased NK cell function thus demonstrated in highly trained persons might result in better resistance against infectious disease.
TL;DR: The results showed a significant and clear relationship between performance gains and NMES administration and withdrawal, and support the use of high-dose NMES as an adjunct to weight training in elite lifters.
Abstract: The response to treatment of high intensity neuromuscular electrical stimulation (NMES) to both quadriceps femoris muscles as an adjunct to ongoing weight training was evaluated using a single subject experimental design. For an elite weight lifter weekly maximal measurements of snatch (S), clean and jerk (CJ), and front squat (SQ) were obtained over 4 months during which the subject weight trained daily for 3 h. The 1st month, baseline data were collected. After baseline measurements, a 1-month period of high-intensity NMES was added to the subject's weight training. NMES was then withdrawn for 1 month and administered once more for 2 weeks. Three quadriceps femoris muscle biopsies were taken, two during the initial baseline period and one just before the end of the first stimulation period. The results showed a significant and clear relationship between performance gains and NMES administration and withdrawal. Steep gains for S, CJ, and SQ were seen after 2 weeks of stimulation, with front squat showing a 20-kg increase within the 1st week of both stimulation periods. Muscle biopsy showed an increased type I fiber area, decreased type IIa and IIb fiber area, and an increase of type II fibers after NMES. The results of this study support the use of high-dose NMES as an adjunct to weight training in elite lifters.
TL;DR: During the outdoor tennis season of 1984 a prospective injury registration was done in 104 randomly chosen elite tennis players, of whom 86% could be followed, and 46 injuries were found: an incidence of 2.3 injuries/player/1000 tennis hours.
Abstract: During the outdoor tennis season of 1984 a prospective injury registration was done in 104 randomly chosen elite tennis players, of whom 86% could be followed. We found 46 injuries: an incidence of 2.3 injuries/player/1000 tennis hours. Men were more frequently injured than women. The prevalence was 0.3 injury/player. Upper extremity injuries were most frequent - 45.7% (21/46). Shoulder injuries were the single most frequent injury - 17% (8/46). The pathophysiology was overuse in 67% (28/42), strains in 14% (6/42), sprains in 17% (7/42), fractures in 2% (1/42), and blisters in 5% (2/42). Players using conventional rackets had more injuries to the upper extremity compared with players using mid/oversized rackets, though the difference was nonsignificant. The importance of impact forces from the tennis stroke in the mechanism of upper extremity injuries is discussed.
TL;DR: A group of 114 previously untrained subjects, 31 females and 83 males, was followed for 18 months while training for a marathon, finding that dehydration above a certain limit appears to increase the frequency of GI disorders.
Abstract: A group of 114 previously untrained subjects, 31 females and 83 males, was followed for 18 months while training for a marathon. Forty-four of the subjects completed a survey regarding fluid intakes and gastrointestinal (GI) disturbances during competition for both their first 25-km race (run after 1 year of training) and their first marathon. GI problems were common. Among the individuals surveyed, 25% had GI complaints in the 25-km race. In the marathon, 52% complained of GI distress. In general, fluid consumption was low (25 km means = 109 ml; marathon w = 577 ml). Body weight losses in the marathon were substantial (w = 3.2%, BW; range 1.5%-6.2%) indicating sweat losses greater than fluid replacement. These losses were greater in men than in women (men w = 3.4% BW; women w = 2.6% BW). GI complaints were not associated with larger drink intakes. In contrast, dehydration above a certain limit appears to increase the frequency of GI disorders. In the marathon, 80% of the runners who lost greater than 4% BW had GI problems. It is possible that reduced blood flow to the GI region is compromised via the exercise itself as well as by a reduced blood volume, which may disrupt normal secretion/absorption of the digestive tract. It may also be that a rising core body temperature, associated with decreased sweating at high levels of dehydration, may be related to GI dysfunction.
TL;DR: It is suggested that blood concentrations of C3 and C4, but not IgG, IgA, or IgM, are decreased during rest, graded maximal exercise, and recovery in marathon runners in comparison with sedentary controls.
Abstract: Eleven marathon runners (42.7 +/- 2.1 yrs, 54.2 +/- 1.8 ml.kg-1.min-1) and nine sedentary controls (44.2 +/- 1.2 yrs, 33.3 +/- 1.1 ml.kg-1.min-1) were studied during 30 min of rest, a graded maximal treadmill test using the Balke protocol, and 45 min of recovery to determine the effects of training and acute exercise on complement and immunoglobulin levels. Three baseline and five recovery blood samples were obtained in addition to repeated 5-min samples during exercise. Data for the exercise period were analyzed using a multiple regression approach to repeated measures ANOVA to allow comparison between groups on a percent VO2max basis. Groups did not differ during any of the three phases for IgG, IgA, or IgM. Resting levels of complement C3 (0.89 +/- 0.05 vs 1.27 +/- 0.10 g/L, P less than 0.001) and C4 (0.19 +/- 0.02 vs 0.29 +/- 0.03 g/L, P less than 0.001) were significantly lower in athletes than in controls. Exercise complement C3 [F(1,18) = 14.1, P = 0.001] and C4 [F(1,18) = 7.6, P = 0.013], and recovery complement [F(1,18) = 19.4, P less than 0.001] and C4 [F(1,18) = 13.5, P = 0.002] were also lower in the athletes than in sedentary controls. Acute increases during exercise were not associated with changes in catecholamines or cortisol. These data suggest that blood concentrations of C3 and C4, but not IgG, IgA, or IgM, are decreased during rest, graded maximal exercise, and recovery in marathon runners in comparison with sedentary controls.
TL;DR: The results suggest that the current protein RDA may be inadequate for athletes engaging in chronic high-intensity endurance exercise.
Abstract: On two separate occasions, five well-trained endurance runners (VO2max = 71 +/- 5 ml/kg/min; means +/- SD) consumed a meat-free diet for 6 days. For one trial the subjects consumed the recommended dietary allowance (RDA) of protein (REC-PRO = 0.86 +/- 0.23 g/kg body wt/day). Protein intake for the other trial was 1.7 times higher (HI-PRO = 1.49 +/- 0.29 g/kg body wt/day). Each subject followed his regular training program (12-16 km running/day), and on day 5 of each diet completed a treadmill run at a similar intensity and duration (75 min at 72% VO2max). Seventy-two hour urinary urea N loss (days 4, 5, and 6 of each diet) and day 5 exercise sweat urea N excretion were measured. Serum urea N and creatinine increased significantly during the treadmill run under both dietary conditions (P less than 0.05). No significances between diet differences were observed in sweat or urinary urea N excretion; however, excretion of both tended to be higher on the REC-PRO diet than on the HI-PRO diet. The differences in protein intake combined with the nitrogen excretion measures resulted in significant differences in estimated whole-body nitrogen retention between the two treatments. Nitrogen retention (means +/- SE) remained positive during the HI-PRO trial (2.41 +/- 1.99 g/day) but was significantly (P less than 0.005) reduced to -5.29 +/- 2.58 g/day during the REC-PRO trial. These results suggest that the current protein RDA may be inadequate for athletes engaging in chronic high-intensity endurance exercise. Future studies are needed to confirm this observation.
TL;DR: The results showed that energy balance (EB) and nitrogen balance (NB) were positive on the first resting day and became negative on the exercise days, and energy balance was positive again on the recovery day whereas NB remained negative.
Abstract: Sustained exhausting exercise is thought to depress appetite and food intake. The aim of the present investigation was to study the effect of intensive cycling exercise, with an energy expenditure comparable to values derived from the Tour de France, on food and fluid intake, energy balance, nitrogen balance, and nutrient oxidation. Thirteen highly trained cyclists consuming a normal carbohydrate (CHO)-rich diet (60 En%) were studied during a 7-day stay in a respiration chamber. Two preparation days were followed by a standardized resting day (3), after which the subjects completed two exhausting exercise days (4-5). On day 6 the standardized resting day was repeated. Food and fluid intake were measured by weighed procedure. Energy expenditure was calculated from continuous gas analysis. Energy and nitrogen losses were calculated from all measured excretes. The results showed that energy balance (EB) and nitrogen balance (NB) were positive on the first resting day and became negative on the exercise days. EB was positive again on the recovery day whereas NB remained negative. Nitrogen losses almost balanced N intakes (1.7 g.kg-1) indicating an increased protein requirement. CHO oxidation exceeded CHO intake indicating endogenous CHO depletion. Contribution of CHO to energy exchange decreased from 51.4% +/- 3.1% on day 4 to 40.6% +/- 3.4% on day 5; this decrease was compensated by an increased fat oxidation. The food consumption pattern during days 4 and 5 was not different from days 2 and 6. In-between meal consumption accounted for 30.5%-34.3% of total energy intake. Fluid consumption was adequate to compensate for the losses.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: It is concluded that resistance training 2 days/week significantly improves knee extension isometric strength; however, the magnitude of strength gain is greater when training is performed 3 days/ week.
Abstract: The purpose of this study was to evaluate the effectiveness of resistance training performed either 2 days/week or 3 days/week. One hundred and seventeen sedentary volunteers were randomly assigned to one of the two training groups or a control group. Twenty-two men (27 +/- 5 years) and 22 women (26 +/- 5 years) trained for 10 weeks. Twenty-five men (26 +/- 5 years) and 22 women (24 +/- 5 years) trained for 18 weeks. Twenty-six subjects served as controls and did not train. Training consisted of a single set of variable resistance bilateral knee extensions performed to volitional fatigue with a weight load that allowed seven to ten repetitions. Prior to and immediately following training, isometric strength was evaluated at 70, 85, 100, 115, 130, 145, 160, and 171 degrees of knee extension with a Nautilus knee extension tensiometer. All groups who trained showed a significant increase in peak isometric strength when compared with controls (P less than 0.01). Groups that trained 3 days/week increased peak isometric strength (10 weeks = 21.2%; 18 weeks = 28.4%) to a greater extent (P less than 0.05) than groups that trained 2 days/week (10 weeks = 13.5%; 18 weeks = 20.9%). We conclude that resistance training 2 days/week significantly improves knee extension isometric strength; however, the magnitude of strength gain is greater when training is performed 3 days/week. These data indicate that the adult exerciser (18 to 38 years) training 2 days/week may derive approximately 80% of the isometric strength benefits achieved by those training 3 days/week.
TL;DR: DHEAS seems to be a more useful stress marker than the plasma cortisol concentration, and remained elevated both in males and females for 1-2 days after the contests, although the amplitude of DHEAS increments was greater after the marathon.
Abstract: In the present study 25 males and 11 females were monitored for an 18- to 20-month training period during which the training distance was gradually increased. The training period was divided into three periods of 6, 5, and 7 months, respectively. The first, second, and third period were concluded with a 15-, 25-, and 42-km road race, respectively. The competitive distance always exceeded the maximal distance covered in any previous training session. Before and after three contests of 15, 25, and 42.195 km, the plasma concentration of testosterone, cortisol, and dehydroepiandrosterone sulfate (DHEAS) were determined. The decrease of plasma testosterone concentration in males was dependent on the distance of the contests. Moreover, the plasma testosterone concentration was increased in males during the course of the training period. In females no clear relation between plasma testosterone levels and the contests could be observed, and no changes in basal levels were found in the course of the training period. DHEAS seems to be a more useful stress marker than the plasma cortisol concentration. The plasma levels of this hormone remained elevated both in males and females for 1-2 days after the contests. The amplitude of DHEAS increments, however, was greater after the marathon.
TL;DR: It was concluded that the improvement in distance-running performance observed in adolescent boys was not dependent upon run training and appears to be attributable to better running economy and an ability in runs of a fixed duration to perform at a higher relative work load.
Abstract: Longitudinal studies of adolescent males have shown that absolute maximal aerobic power (VO2max) and distance-running performance improve with age, while VO2max expressed relative to body mass remains stable. These earlier studies used subjects that were engaged in distance-run training; therefore, it was not possible to assess the relative importance of growth and/or run training to improved performance. The purpose of this study, therefore, was to quantify longitudinal changes in VO2max, running economy (RE), and distance-running performance in non-run-trained young males. Six subjects were tested at mean ages of 9.9 (T1) and 16.8 years (T2). Statistical tests of mean values revealed that over the 7-year period, relative VO2max remained unchanged (T1, 48.9 ml.kg-1.min-1; T2, 47.8 ml.kg-1.min-1) and RE improved (T1, 234.2; T2, 202.8 ml.kg-1.km-1), 9-min run distance increased (T1, 1637 m; T2, 2115 m), and the estimated percent of VO2max incurred during the 9-min run increased from 85.8% (T1) to 99.5% (T2). It was concluded that the improvement in distance-running performance observed in adolescent boys was not dependent upon run training. In view of the fact that maximal aerobic power remained stable, this change appears to be attributable to better running economy and an ability in runs of a fixed duration to perform at a higher relative work load.
TL;DR: The results showed that the cyclists receiving Mf were able to maintain EB during sustained exercise days in contrast to when receiving N and to subjects receiving FM, and with Mf treatment CHO intake increased, and carbohydrate balance remained positive.
Abstract: Field studies during the Tour de France indicated that cyclists consume 30% of daily energy intake as liquid carbohydrate (CHO)-enriched nutrition with the goal of maintaining energy and CHO balance. The aim of the present investigation was to study the effect of such dietary manipulation during 2 days of long-lasting exhausting cycling on food and fluid intake, energy balance, nitrogen balance, and nutrient oxidation. Thirteen highly trained cyclists were divided into two subgroups receiving ad libitum either a primarily maltodextrin-based beverage (Mf) (20% w/v, 85% maltodextrin, 15% fructose) or a 50/50% composed fructose-maltodextrin (FM) beverage in addition to their normal diet. The study was performed during a 7-day stay in a respiration chamber (2 preparation days, 1 standardized resting day, 2 cycling days, 1.5 standardized recovery days), allowing for continuous gas analysis, weighed food and fluid intake procedure, and collection of excretes. The data of this study were compared with data from the same subjects receiving a normal CHO-rich diet (N) (60 En%) in a separate experiment. The results showed that the cyclists receiving Mf were able to maintain EB during sustained exercise days in contrast to when receiving N and to subjects receiving FM. With Mf treatment CHO intake increased, up to 80 En% (17.5 +/- 1.0 g.kg-1 BW) and carbohydrate balance remained positive. The subjects receiving FM had the largest CHO oxidation, calculated from R. Protein oxidation significantly increased in N and FM as a result of exercise but not in Mf. The latter subjects were in slightly negative nitrogen balance at a protein intake level of 1.4 g.kg-1 BW.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: PWC was dramatically reduced while pulmonary function was slightly increased compared with predicted normal values, indicating that the low fitness levels were caused by physical inactivity, and it is a strong argument for integrating physical fitness training into psychiatric treatment programs.
Abstract: Physical work capacity (PWC) and pulmonary function were measured shortly after admission in 90 inpatients with anxiety and depressive disorders. PWC was dramatically reduced while pulmonary function was slightly increased compared with predicted normal values. This indicates that the low fitness levels were caused by physical inactivity, and it is a strong argument for integrating physical fitness training into psychiatric treatment programs. Values obtained by direct measurement and indirect calculations of PWC were highly correlated (R = 0.67). The mean differences between the two tests were 21% on an individual level and 5% on a group level.
TL;DR: It was concluded that relative maximum anaerobic power is distinctly greater in elite high school wrestlers than less successful peers, and it may be of benefit for wrestlers of lower caliber to decrease body fat, increase fat-free weight, and increase total body power through training.
Abstract: The purpose of this investigation was to identify physiologic differences between elite high school-age wrestlers and nonelite wrestlers of comparable age, weight, and training experience. Two groups of junior wrestler, elite (n = 18) and nonelite (n = 18) were measured for maximum aerobic power (treadmill run), maximum anaerobic power of the arms and legs (Wingate test), and skinfold thickness. On the average (+/- SE) elite juniors had a VO2max of 52.6 +/- 2.0 ml/kg.min-1, 376 +/- 20 W for arm power, and 540 +/- 25 W for leg power. The nonelite group had a VO2max of 51.5 +/- 1.4 ml/kg.min-1 and 331 +/- 22 W and 467 +/- 29 W for arm and leg power, respectively. Ttests were computed to identify differences between the groups. The results revealed significant differences in four skinfold thicknesses, absolute anaerobic leg power, and relative anaerobic power of arms and legs. It was concluded that relative maximum anaerobic power is distinctly greater in elite high school wrestlers than less successful peers. In light of the results, it may be of benefit for wrestlers of lower caliber to decrease body fat, increase fat-free weight, and increase total body power through training.
TL;DR: Observations suggest an increased lipid utilization by muscle during exercise in the L-C-treated group, which has further possibilities for improving performance during submaximal exercise.
Abstract: This study was undertaken to determine the effects of L-carnitine addition to the diet during submaximal exercise in endurance-trained humans. Ten subjects (VO2max: 62 ml.kg-1.min-1) performed a control test (C) (45 min of cycling at 66% of VO2max) followed by 60 min of recovery in a sitting position. Each subject repeated this trial after 28 days of placebo (P) and L-carnitine (L-C) treatment (double-blinded cross-over design). The dose of each treatment was 2 g/day. There were no differences between the C and P tests. The respiratory quotient was lower (p less than 0.05) with treatment than with P or C during exercise. In addition, oxygen uptake, heart rate, blood glycerol, and resting plasma free fatty acid concentrations presented a nonsignificant trend toward higher values in L-C than in the C or P groups. These observations suggest an increased lipid utilization by muscle during exercise in the L-C-treated group. This effect has further possibilities for improving performance during submaximal exercise.
TL;DR: The volume-regulating hormones (AVP and aldosterone) may play an important role during and immediately after the run but not in the longer recovery period (t2 and t3), and it is suggested that this phenomenon was caused by an influx of proteins into the vascular space.
Abstract: Fluid-regulating hormones [arginine vasopressin (AVP) and aldosterone] as well as electrolytes, plasma volume (PV), and plasma proteins were studied in 16 well-trained male amateur runners (mean age 31.8 years) before t0), immediately after (t1), and 60 min (t2) and 22 h (t3) after a marathon run. Immediately after the run PV was significantly decreased by 12.1%, whereas the concentration of plasma proteins increased by 13.9%, sodium by 5.8 mMol.l-1, and potassium by 0.58 mMol.l-1, respectively. Aldosterone increased by 1089 pg/ml and AVP by 9.0 pg/ml. PV was significantly increased 22 h after the run by 10.6% (P less than 0.001) and plasma proteins were increased by 1.0% (P greater than 0.05), whereas aldosterone and AVP as well as electrolytes returned to control values. At t1, and particularly at t2 and t3, the total plasma protein concentration increased much more than could have been expected from changes of PV. It is suggested that this phenomenon was caused by an influx of proteins into the vascular space. This might also be the reason for the expanded PV especially in the longer recovery period at t3. The volume-regulating hormones (AVP and aldosterone) may play an important role during and immediately after the run but not in the longer recovery period (t2 and t3).
TL;DR: A gender difference in plasma enzyme activity increase (females demonstrated a lower increase) occurred only after the marathon, and the estimated amount of muscle damage was found to be small.
Abstract: One hundred fourteen sedentary volunteers (34 +/- 8 years) took part in an endurance training study to be completed after 18-20 months with a marathon. Ultimately, 60 males and 18 females achieved that goal. The training program, carefully supervised, was divided into three periods with a maximum of 45-, 70-, and 110-km week training volume and concluded with a performance race of 15, 25, and 42.2 km, respectively. Three days before and 3 and 5 days after each race, 35 subjects were selected to perform a progressive treadmill test and the remaining subjects participated in field tests of 400 and 1000 m. A significant decrease in half-life time of CK enzyme plasma activity after running long distances in the course of the study from 20 h to 13 h was observed. Based on plasma enzyme activity and supposing that the total enzyme content left the muscle fiber, the estimated amount of muscle damage was found to be small. A gender difference in plasma enzyme activity increase (females demonstrated a lower increase) occurred only after the marathon.
TL;DR: Within a 3-year period, from 1980 to 1982, 1124 sports injuries of children aged 6-15 years were treated in the Turku University Central Hospital casualty department, with boys injured most commonly in ice hockey and football and girls in skating and riding.
Abstract: Within a 3-year period, from 1980 to 1982, 1124 sports injuries of children aged 6-15 years were treated in the Turku University Central Hospital casualty department. Two-thirds (69%) of the injuries were sustained by boys. Sports injuries represented 21% of the diagnoses related to accidents in this age group. Half of the sports accidents occurred during the 4 winter months. Boys were injured most commonly in ice hockey (36%) and football (20%) and girls in skating (18%) and riding (18%). One quarter (26%) of the injuries were located in the head and neck, 36% in the upper extremities, 33% in the lower limbs, and 4% in the trunk. The most common types of injuries were fractures (26%), sprains and strains (24%), contusions (22%) and wounds (17%). The proportional occurrence of fractures increased with age in boys (P less than 0.001) and decreased in girls (P less than 0.001), luxations (P less than 0.05) and sprains (P less than 0.001) increased with age in girls; skull injuries (P less than 0.01) and contusions and wounds (P less than 0.001) decreased in boys. Girls had more sprains (P less than 0.001) but fewer contusions and wounds (P less than 0.001). Most of the injuries were mild; 9% of the cases were hospitalized. Minor surgery was performed in 16% and reconstructive surgery in 2% of all injuries. About 70% of the injuries occurred in nonorganized sports. Language: en
TL;DR: A longitudinal growth study of young elite female gymnasts and moderatelytrained swimmers and moderately trained swimmers found patterns of recalled parental growth and pubertal maturation were compared with those of parents of 25 sedentary school girls, and parents of gymnasts were significantly lighter and shorter than parents of swimmers or controls.
Abstract: Whereas intensive and regular physical training is known to alter female reproductive function, its potential role in growth is still controversial. At the beginning of a longitudinal growth study of young elite female gymnasts (n = 34, 15-25 h/wk training) and moderately trained swimmers (n = 19, 5-15 h/wk), patterns of recalled parental growth and pubertal maturation were compared with those of parents of 25 sedentary school girls. These data were also correlated to the height, weight, pubertal development as well as adult height prognosis of their daughters. Bone age was estimated using the methods of Greulich-Pyle and Tanner (RUS score) and adult height prognosis using the methods of Bayley-Pinneau (BP), Roche-Wainer-Thissen (RWT), and Tanner et al. (TW2). Parents of gymnasts were significantly lighter (fathers: P = 0.027; mothers: P = 0.038) and shorter (fathers: P = 0.034; mothers: P less than 0.001) than those of swimmers and controls. Consequently, target heights of gymnasts were also significantly shorter (P less than 0.001). Recalled menarche occurred significantly later (P = 0.030) in mothers of gymnasts who, in turn, grow much alike their mothers. At the first visit, the gymnasts were shorter and lighter for age than swimmers and controls. Their bone age (11.0 +/- 1.3 years, mean +/- SD) was retarded (P less than 0.001) when compared with chronological age (12.6 +/- 1.2 years). Adult height prognosis was lower for gymnasts than for other girls (BP: P less than 0.001; RWT: P = 0.023, TW2: P less than 0.001), but adequate for target height range.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: The use of 60%-95% of maximal heart rate, heart rate reserve, and VO2peak as exercise training intensities was examined in sedentary women, and these intensities were related to HR andVO2 observed at the lactate threshold (LT) and fixed blood lactate concentrations of 2.0, 2.5, and 4.0 mM.
Abstract: The use of 60%-95% of maximal heart rate (HR max), heart rate reserve (HRR), and VO2peak as exercise training intensities was examined in sedentary women, and these intensities were related to HR and VO2 observed at the lactate threshold (LT) and fixed blood lactate concentrations of 2.0, 2.5, and 4.0 mM. Thirty-three subjects (means age = 32.5 +/- 3.9 yrs; means ht = 164.2 +2- 5.0 cm; means wt = 67.6 +/- 13.9 kg) completed a VO2/LT treadmill test using a level running protocol. The values at LT, 2.0, 2.5, 4.0 mM, and peak for VO2 were 22.3, 29.0, 31.0, 36.2, and 39.1 ml/kg.min-1, respectively; for velocity were 107.0, 128.9, 135.8, 152.8, and 164.4 m/min, respectively; and for HR were 142.1, 162.9, 169.4, 183.2, and 189.7 bts/min, respectively. The minimum intensity necessary for the majority of subjects to be above LT (n = 17) was 75% HR max while 90% HR max was required for the majority of subjects to be above 2.0 mM (n = 23) and 2.5 mM (n = 19). At 95% HR max 12 subjects were above 4.0 mM. For the majority of subjects to be above LT (n = 18), 55% HRR was necessary; 75%, 85%, and 95% HRR was required for the majority of subjects to be above 2.0 mM (n = 18), 2.5 mM (n = 19), and 4.0 mM (n = 20), respectively. For percent VO2peak, the intensities required for the majority of subjects to be above LT, 2.0 mM, 2.5 mM, and 4.0 mM were 55%, 75%, 80%, and 95% VO2peak, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)