Exogenous fructose 1,6-diphosphate (FDP), a glycolytic intermediate, increases blood ATP and 2,3 diphosphoglycerate levels, facilitates the dissociation of oxygen from hemoglobin, and increases red blood cell flexibility. These mechanisms explain why it has been effective in enhancing energy production in a variety of ischemic conditions. The present study was undertaken to determine whether FDP could enhance oxygen supply and thus improve exercise performance in patients with peripheral vascular disease. Ten male patients (mean age 63 +/- 5 years) with peripheral vascular disease performed symptom-limited exercise testing after randomized, double blind infusion of either 200 mg/kg body weight FDP or placebo. Data were evaluated at rest, at a matched submaximal workload (2-3 MPH/0% grade), and at peak exercise, defined as the occurrence of moderately severe claudication. No differences were observed in heart rate, blood pressure, gas exchange data, time to the onset of claudication or peak exercise, or lactate and 2,3 diphosphoglycerate levels. In contrast to previous studies performed among patients with peripheral vascular disease and other studies using more severe hypoxic conditions, FDP did not affect the respiratory gas exchange or exercise capacity of patients with exertional claudication.
The diclofenac epolamine topical patch 1.3% was designed to deliver analgesic concentrations of diclofenac to an underlying soft tissue injury site, while limiting systemic exposure to diclofenac. This randomized, double-blind, placebo-controlled study evaluated the safety and efficacy of the diclofenac epolamine topical patch for the treatment of acute pain due to minor soft tissue injury. Patients (18-65 years, inclusive) with clinically significant minor soft tissue injuries (mild or moderate sprain, strain, or contusion) incurred within 7 days of study entry and having pain scores ≥ 5 on a Visual Analog Scale of 0-10 were enrolled. Patients were randomized to receive the diclofenac epolamine topical patch (n=207) or placebo patch (n=211) application twice daily for 14 days or until pain resolution. Patients recorded pain scores every 12 h at the time of patch removal using the Visual Analog Scale. Investigator-assessed global response to therapy was also evaluated. Safety data were collected throughout the study. Twice-daily treatment with diclofenac epolamine topical patch produced a statistically significant reduction in mean pain score relative to baseline by an additional 18.2% in the diclofenac epolamine topical patch group (0.435 ± 0.268) compared with the placebo group (0.532 ± 0.293) (p=0.002; overall) beginning after application of the second patch. Consistent with this treatment effect, median time to pain resolution was shortened by 2 days in the diclofenac epolamine topical patch group relative to the placebo group (p=0.007). These results were reinforced independently by investigators who reported treatment as good or excellent for 58% of diclofenac epolamine topical patch-treated patients compared with 49% in the placebo patch group (p=0.008). The most common adverse events were treatment site related (n=16, 7.9% diclofenac epolamine topical patch; n=12, 5.8% placebo patch). Most (80%) patients reported tolerability as excellent or good. In conclusion, the diclofenac epolamine topical patch provides effective, rapid pain relief for the treatment of acute pain from minor soft tissue injury and appears generally safe and well tolerated.
We examined the effects of listening to music on attentional focus, rating of perceived exertion (RPE), pacing strategy and performance during a simulated 5-km running race. 15 participants performed 2 controlled trials to establish their best baseline time, followed by 2 counterbalanced experimental trials during which they listened to music during the first (Mstart) or the last (Mfinish) 1.5 km. The mean running velocity during the first 1.5 km was significantly higher in Mstart than in the fastest control condition (p<0.05), but there was no difference in velocity between conditions during the last 1.5 km (p>0.05). The faster first 1.5 m in Mstart was accompanied by a reduction in associative thoughts compared with the fastest control condition. There were no significant differences in RPE between conditions (p>0.05). These results suggest that listening to music at the beginning of a trial may draw the attentional focus away from internal sensations of fatigue to thoughts about the external environment. However, along with the reduction in associative thoughts and the increase in running velocity while listening to music, the RPE increased linearly and similarly under all conditions, suggesting that the change in velocity throughout the race may be to maintain the same rate of RPE increase.
Forty-two patients referred to the outpatient clinic of Hagavik Orthopaedic Hospital within 3 weeks after an acute knee injury was found by arthroscopy to have a partial or total tear of the anterior cruciate ligament (ACL). In these patients, the results of clinical tests and instrumented laxity tests without anesthesia prior to the arthroscopy were analyzed. The Lachman test and the maximum anterior pull (150-200 N) KT-1000 instrumented test revealed abnormal laxity in 33 and 37 of 42 cases, respectively. Both tests revealed abnormal laxity more often than the KT-1000 test using 67 N (10/42) and the maximum anterior pull KT-1000 instrumented test also revealed abnormal laxity more often than the KT-1000 test using 89 N (25/42). By logistic regression analysis, the maximum anterior pull KT-1000 instrumented test was associated with rupture of the ACL (partial or total rupture). The results show that adequate anterior pull has to be used to overcome muscle tension to reveal abnormal laxity in acute ACL tears using the KT-1000 arthrometer.
This study examined the relationships between body composition, peak oxygen consumption and 1000-m time trial performance of female outrigger canoeists.
Female outrigger canoeists (n = 17) completed anthropometric profiling and a 1000-m outrigger ergometer time trial, during which expired air was measured continuously and analysed at 15-s intervals for determination of peak oxygen consumption. Heart rate, stroke rate and power output were also recorded at 15-s intervals. Blood lactate was measured immediately and at 3-, 5- and 7-min post-exercise. Mean power output, peak power output and progressive split times were highly correlated (r > 0.80) to 1000-m performance. Arm girths, humerus breadth, mesomorphy, peak oxygen consumption, ventilation, mean heart rate and peak lactate were moderately correlated (r > 0.50) to 1000-m performance. Stepwise multiple regression analysis verified that mean power output and to a lesser extent flexed arm girth, humerus breadth, waist girth and sitting height can predict 1000-m performance. Enhanced 1000-m performance of female outrigger canoeists appears to be achieved through a combination of greater power production and maintenance, a muscular stature and to a lesser extent, a higher aerobic capacity. These characteristics should be considered when selecting crews.
In sprinting events of short duration, performance depends not only on the mean external power output and the frictional losses but also on the distribution of energy over the race. To investigate the optimal distribution of anaerobic energy during cycling the 1000 m time trial and the 4000 m pursuit, we simulated a power equation which contains expressions for the production of aerobic and anaerobic power, for frictional losses and for the rate of change of kinetic energy. Parameters for air- and rolling resistance were derived from the literature and the equations for aerobic and anaerobic power production were based on supra-maximal bicycle ergometer tests. Simulated lap and final times were compared to those realized by the best four athletes during the 1990 World Championships. The mean final times of these athletes of 64.1 s and 272.6 s for the 1000 m and 4000 m respectively were closely approximated by the simulated times of 63.7 s and 281.3 s. The simulations show that performance in the 1000 m race depends to a great extent on a large power output at the onset of the race. Moreover, it is demonstrated that this distance should be cycled in an all out fashion and not with a uniform velocity after the start despite the higher air frictional losses. For the 4000 m pursuit it appears to be more effective to perform a short but powerful start and then continue the race with a constant or only slightly decreasing power output.
Recreational scuba diving is a sport of increasing popularity. Previous studies indicating subtle brain injury in asymptomatic divers imply a cumulative effect of minor neural insults in association with diving for professional and/or recreational purposes, over the long-term. This is the first study to investigate putative neural tissue burden during recreational scuba diving by measuring circulating levels of S-100B, a sensitive biomarker of brain injury. 5 male divers performed 3 consecutive dives under conservative recreational diving settings (maximum depth 15 m, duration of dive 56 min, ascend rate 1.15 m/min) with an interval of 12 h between each session. Although a small increase in serum S-100B levels after each dive was apparent, this increase did not quite reach statistical significance (p=0.057). Moreover, no abnormal S-100B values were recorded (mean baseline: 0.06 μg/L, mean post-dive: 0.086 μg/L) and no effect of the 3 consecutive dives on changes in S-100B levels was detected. These results suggest that under the experimental conditions tested, diving does not seem to have a discernible and/or cumulative impact on central nervous system integrity. The extent to which variable diving settings and practices as well as individual susceptibility factors underlie putative neural tissue burden in asymptomatic divers, remains to be established.
Permanent neurological dysfunction is the primary medical concern of boxing. Recently it was reported that patients presenting elevated levels of the glial protein S-100B in serum after minor head injuries are more prone to develop neuropsychological deficits than patients with lower levels of S-100B protein. We assessed this protein before and after amateur boxing competitions (n = 10) and sparring bouts (n = 15). In several control groups, we investigated S-100B levels of participants before and after a 25 km race (n = 11), jogging (10 km, n = 12), short-term running (n = 12), and heading footballs (n = 12). There was an increase in S-100B protein after boxing and the running disciplines but not after ergometer cycling or soft heading of footballs. The increase in S-100B protein concentrations due to competitive boxing and after the 25 km race was significantly higher than that after performing other disciplines (p < 0.001). There was no significant difference between the increases caused by sparring and the running disciplines (p = 0.21). The number and severity of the strikes to the head correlated significantly with the increase in the S-100B protein levels. Levels of S-100B protein known to be associated with neuropsychological deficits were not reached in our study. In professional boxing, much higher levels are to be expected and would be worthy of investigation.
Eleven weight-trained athletes (age X +/- SD = 33 +/- 5 yrs, weight = 72 +/- 10 kg) with a maximal performance in bench press at the beginning of the study (116 +/- 19 kg) were studied at rest, after a standardized submaximal training session, and after a maximal session once a month for 4 months to study the blood metabolites and hormonal changes during weight lifting. The submaximal load was six series of eight bench presses at 70% of maximal performance presses, and the maximal load was the maximal number of repetitions at the same work load. The levels of several metabolites (lactate, glycerol, triglycerides, beta-OH-butyrate) and hormones (norepinephrine and epinephrine) increased (P less than 0.05) after submaximal work and more after maximal work. Glucose, FFA, acetoacetate, insulin, testosterone, and cortisol did not change significantly or consistently. Lactate after maximal work was higher after the 4th training month (P less than 0.05). Other variables did not change much with training while the maximal number of repetitions in the last series increased slightly (P less than 0.05). In general, the changes observed were smaller than the ones reported for endurance or interval running, which use larger muscle groups. Nevertheless, weight lifting induced changes in blood metabolites which reflect a mobilization of both carbohydrates and lipids stores for energy.
The aim of this study was primarily to investigate differences in onset and progression of puberty, body composition, and growth between groups of young female gymnasts, schoolgirls and girl swimmers, and secondly to determine the relations between the pubertal events and body composition, especially the amount of body fat, or training activities.
In 1980, 1981, and 1982, 668 female gymnasts, 298 schoolgirls and 98 girl swimmers were examined. The gymnasts were subdivided into three different groups, namely, the talented, the nontalented, and the selection group.
The onset of puberty and menarche was delayed in the gymnastic groups by about 1 or 2 years compared to the schoolgirls and girl swimmers. The gymnasts were on average smaller than the schoolgirls and girl swimmers. These differences became even more pronounced after the age of 10 years. This may be caused by a delayed growth spurt within the gymnastic groups in combination with self-selection. Furthermore, the gymnasts were leaner than the other two groups: the girl swimmers had a greater fat mass and a greater lean body weight, while the schoolgirls had more fat mass.
Relations were found between the parameters of pubertal development and calculated fat mass and also between breast development, pubic hair growth and age, body height, body weight, and calculated lean body weight.
Only in the swimming group were training hours per week related to body height, body wieght, lean body weight, and pubic hair growth.
The aim of this study was to determine the physical activity levels of a sample of young children. Data were collected using direct, continuous observation by trained observers. The observational method utilised a points system to differentiate intensity of physical activity. Observations were carried out during school break times, lunch times and physical education lessons and during free time outside of school. The sample consisted of 93 girls and 86 boys aged between 5 and 11 years. Only 38 children (21%) engaged in a sustained 20-min period of moderate to vigorous physical activity (MVPA), but nearly all children (95%) took part in a 5-min period of MVPA. The highest recordings of MVPA occurred during school break times but MVPA was less prominent during free time outside of school. One hundred and seventy eight children were observed during school physical education lessons. Sustained MVPA was particularly low during physical education lessons with only 13 children (8%) participating in at least one sustained 10-min period. There appeared to be no difference in activity levels between boys and girls or between children of differing ages. During all observation periods the main activity of the child was recorded. Soccer, brisk walking, general play and chasing games were the most common activities. The results are disturbing since preadolescent children appear to be engaging in very little sustained, playful physical activity during their free time outside of school. If childhood is considered to be the most active stage of life there must be concern for the future. There is a need for health professionals to promote active lifestyles from birth.
The aim of this study was twofold: a) to examine the association between eating frequency and body composition in children, and b) to identify possible factors that may explain this relationship. Body composition (anthropometry) and dietary intake (3-day food records) were assessed in a cohort of 151 children. After excluding the underreporters (n = 20), data from 131 children (66 boys and 65 girls) aged 9.9 +/- 0.1 yr with a BMI of 19.6 +/- 0.4 kg/m (2) (means +/- se) were used for further analysis. Children were categorized in tertiles based on the daily number of eating episodes. Physical activity was assessed in a subgroup of 48 volunteers with 4-day accelerometry (RT3, Stayhealthy Inc., Monrovia, CA, USA). The number of eating episodes was inversely associated (p < 0.05) with the sum of skinfolds (r = - 0.17) and % body fat (r = - 0.18) after controlling for age and sex. Frequent eaters presented lower total (p < 0.05) and central adiposity (p < 0.01) compared with the infrequent ones. This was despite the fact that energy intake was higher for the frequent eaters (2077.0 +/- 64.3 vs. 1813.0 +/- 37.8 kcals/day for the frequent and the infrequent eaters, respectively, p < 0.05). Actually, frequent eaters devoted more time to physical activity than infrequent ones (624.7 +/- 13.5 vs. 559.2 +/- 23.1 min/day, p < 0.05). In conclusion, high eating frequency was associated with more favorable body composition in this cohort of school children. Increased energy expenditure due to physical activity may, at least in part, explain the favorable body composition of children who eat frequently.
Previous studies in adults have indicated a rise in the metabolic cost of increasing cycling cadence at constant work rates. This study examined the metabolic and cardiovascular responses to pedaling rates of 41, 63, and 83 rpm at both zero-load and 50-watts load in 12 prepubertal boys. Increasing cadence from 41 to 83 rpm produced a 52.9% and 23.1% rise in gross energy expenditure in the two work conditions, respectively, despite the constant external work rate. This augmented energy expenditure was accounted for entirely by internal work, as no changes in work metabolic cost (difference between loaded and unloaded cycling) were observed as cadence increased. The rise in energy expenditure with higher pedaling rate during the zero load and 50 watt conditions was accompanied by increases in both heart rate and stroke volume. Arterial venous oxygen difference did not change with increased cadence but was significantly higher with loaded cycling, suggesting that skeletal muscle pump effectiveness is negatively influenced by increased load but not by increased pedaling rate.
A high-impact exercise and a lifestyle intervention were implemented over a 9-week period; changes in bone and body composition were compared to controls. Sixty-one children volunteered from three randomly selected schools. Each school was randomly assigned to either a structured exercise (STEX) intervention, a lifestyle intervention (PASS) or control (CONT). Bone mineral content (BMC) and density (BMD) of total body, femoral neck and lumbar spine were measured as well as fat and lean mass at baseline and post-intervention by dual-energy X-ray absorptiometry. The STEX intervention resulted in an additional mean increase in total body BMC of 63.3 g (p = 0.019) and an additional increase of 0.011 g . cm (-2) (p = 0.018) for BMD over increases observed by controls. Bone mineral increases observed for the PASS intervention were not significant compared to the control group (p > 0.05). Neither intervention produced significant increases in bone mineral at femoral neck or lumbar spine sites (p > 0.05) compared with the controls. No significant changes were found in fat mass index (p > 0.05), lean mass index (p > 0.05) or percent body fat (p = 0.09) in any groups. Structured impact exercise promoted significant and clinically relevant increases in bone measures, without significant changes to body composition. A larger, definitive randomised trial is needed to confirm the present results.
Our aim is to propose a selection procedure on the basis of motor abilities. Within this scope, we have particularly studied balance as one of the selection criteria for young female gymnasts. We have used the combination of two standardized tests: the beam-walking test and the stork-standing test.
Four groups of young females (aged 8 to 11 years) were tested. The results indicate that the talented group (n = 23, those participating in national training) has better balance in comparison to the control group (n = 37, gymnasts only participating at club level) and the average group (n = 32, girls not taking part in gymnastics). The results are independent of age, height, and weight, which justify the conclusion that balance is stabilized before the age of 8 years. The fourth group (n = 192) are girls who took part in the. selection procedure in 1979 and 1980. We divided this group in 1981 into a non-selected group (n = 121), a discharged, selected young talented group (n =42), a selected young talented group (n = 16), and an older talented group (n = 13). We discuss the results of these groups at the time of the selection procedure. The two talented groups show better results on the balance tests than the discharged, selected group and the non-selected group. There is no relationship to the results of the total selection test.
The results indicate that these tests can be used as one of the selection criteria within the selection procedure for young female gymnasts.
To assess changes of sex hormones, cortisol, prolactin (PRL) and beta-endorphins in an exhaustive aerobic performance, blood samples were taken in 11 endurance trained runners (R) along an ultra-marathon race of 110 km (T1 before the start, T2 at km 33, T3 at km 75 and T4 immediately after completing the race). Results were compared to a control group (C) who followed the race. Cortisol (p < 0.001) and beta-endorphins (p = 0.009) showed a significant increase during the race without significant modification after T2. Testosterone decreased along the race (p = 0.02). Luteinising hormone (LH) was lower at the end of the race as compared to the start in the R. No modification of PRL was noticed in the runners. Most of the modifications except for testosterone were observed from the start to T2, even in exhaustive performance no further modification was noticed from that point onwards.
β1-adrenergic receptors (ADRB1) and Gαs proteins (GNAS) play important roles in the regulation of cardiac function. The present study sought to investigate whether ADRB1 Arg389Gly (rs1801253), GNAS -1211 G/A (rs6123837) and GNAS 2291 C/T (rs6026584) variants are associated with left ventricular function and exercise tolerance in heart failure patients. 61 heart failure patients completed a 6-month exercise-training programme. Left ventricular ejection fraction (LVEF), mitral inflow velocities (deceleration time, and E/A ratio) and exercise tolerance (METs) were assessed at baseline and following exercise training. There were no associations between the studied variants and LVEF or E/A ratio measured at baseline and after exercise training. Deceleration time of early mitral flow was higher at baseline in GNAS -1211G allele carriers compared with -1211A allele homozygotes (P<0.05). Exercise training attenuated deceleration time in -1211G allele carriers (P<0.05) but not in -1211A allele homozygotes. Moreover, ADRB1 389Gly homozygotes had a greater training-induced increase in exercise tolerance than 389Arg homozygotes (P=0.04). This study shows that the functional GNAS -1121 G/A polymorphism is associated with diastolic function at baseline and in response to exercise training in heart failure patients. Furthermore, our data suggest that ADRB1 Arg389Gly polymorphism may influence exercise tolerance.
Erythropoietin gene expression is stimulated by hypoxia-inducible factor 1 and inhibited by GATA. Thus, drugs that attenuate the action of GATA and/or potentiate the action of HIF-1 may increase Epo production and hemoglobin concentration. The effects of such drugs on endurance performance and the potential mechanisms by which they may exert effects are unclear. In Hep3B cells, we showed that K-11706 inhibits GATA binding activity, but enhances HIF-1 binding activity. However, the expression levels of GATA and HIF-1 protein were not changed by the addition of K-11706. We investigated the effects of K-11706 on Epo and Hb concentrations, hematocrit and endurance performance of mice (total number of mice = 40). K-11706 was dissolved in polyethylene glycol and administered via oral tube feeding to mice for either five or eight days. Endurance performance was assessed using a treadmill. Muscle fibers from the quadriceps muscles of mice were stained with ATPase. Administration of 3 mg/kg K-11706 for five or eight days significantly increased erythropoietin concentrations, hemoglobin concentrations, hematocrit and endurance performance, but the diameters of cross-sections and ratios of type I, IIA and IIB muscle fibers were not affected.
Erythropoietin promotes the production of red blood cells. Recombinant human erythropoietin is illicitly used to improve performance in endurance sports. Expression of the ERYTHROPOIETIN gene is negatively controlled by the transcription factor GATA-binding protein (GATA). Specific GATA inhibitors have recently been developed as novel drugs for the management of anemia. These drugs could, therefore, be illicitly used like recombinant human erythropoietin to improve performance in sports. To examine alterations in levels of plasma protein after administration of GATA inhibitors, proteomic analyses were conducted on mouse plasma samples treated with the potent GATA inhibitor K-11706. The analysis based on gel electrophoresis identified 41 protein spots differentially expressed when compared with normal plasma. Each spot was identified with liquid chromatography coupled to tandem mass spectrometry and 2 of them, fetuin-B and prothrombin, were verified by Western blotting. The results showed that the expression of fetuin-B in mice plasma was increased by K-11706, but not by recombinant human erythropoietin or hypoxia. These results suggest the potential of proteomic-based approaches as tools to identify biomarkers for the illegal use of novel drugs (e.g., GATA inhibitors). Also, fetuin-B could be a sensitive marker for the detection of abuse of GATA inhibitors.
The aim of the present study was to explain the inter-individual variability in running time to exhaustion (tlim) when running speed was expressed as a percentage of the velocity, associated with maximal oxygen uptake (vVO2max). Indeed for the same percentage of vVO2max the anaerobic contribution to energy supply is different and could be dependent on the critical velocity (Cv) and also on the maximal running velocity (vmax). Ten subjects ran four tlim at 90, 100, 120, and 140% of vVO2max; mean and standard deviation for tlim were 839 +/- 236 s, 357 +/- 110 s, 122 +/- 27 s, and 65 +/- 17s, respectively. Each velocity was then expressed 1) as a percentage of the difference between vVO2max and Cv (%AeSR); 2) as a percentage of the difference between vmax and Cv (%MSR); 3) as a percentage of the difference between vmax and vVO2max (%AnSR). Highest correlations were found between tlim90 and tlim100 and velocity expressed as %MSR (r = -0.82, p < 0.01 and r = -0.75, p < 0.01), and between tlim120 and tlim140 and velocity expressed as %AnSR (r = -0.83, p < 0.01 and r = -0.94, p < 0.001). These results show that the same intensity relative to aerobic contribution did not represent the same absolute intensity for all and could partly explain variability in tlim. Therefore expressing intensity as a percentage of MSR for sub-maximal and maximal velocities and as a percentage of AnSR for supra-maximal velocities allows individual differences in anaerobic work capacity to be taken into account and running times to exhaustion to be predicted accurately.
From an experience of a large number (1261) of cases of mountain frostbite, an attempt is made to explain its pathophysiological mechanisms and describe the different modalities which to now allow early prognosis to be made. Laser-Doppler, microwave thermography, nuclear magnetic resonance (31P spectroscopy) and bone scintigraphy (technetium 99) are some of the investigations which deserve a special attention. Treatment is discussed, which still appears to be limited to saving viable tissue, especially for severe frostbite lesions, the only ones which pose problems. Rapid rewarming is a keystone of therapy. The role of haemodilution, vasodilators, sympathetic blockade and surgery is also discussed.
Up to now only the analysis of 13CO2 in separate breath-gas samples after administration of [13C]-labelled carbohydrates with intervals of several minutes in between has been available for analyses of the exogenous glucose oxidation during exercise. Our studies show the use of rapid respiratory mass spectrometry for breath-by-breath analysis to determine exogenous glucose utilization. Six male triathletes performed two exercise tests of 100-min duration each on a cycle ergometer. In both tests 5 min after the beginning of cycling glucose was administered. In test 1 30 g natural glucose was given, in test 2 a mixture of 1.5 g [13C1]-glucose and 28.5 g natural glucose. The work rate was regulated to keep constant 90% of the VO2 at the VO2 levelling off (VO2max) measured in a short ramp test. The resulting work rate was at 260.2 +/- 9.5 watts in test 1 and at 276.3 +/- 12.1 watts in test 2. Respiration gases and the end-tidal concentrations of 12CO2 (12C) and 13CO2 (13C) were calculated breath-by-breath online. The course of the ratio [13C/12C] reflects the course of exogenous glucose utilization. Onset of utilization was 10.5 +/- 5.5 min following oral administration. Maximum utilization was attained at 53.1 +/- 9.8 min with a maximal rate of oxidation of 0.36 +/- 0.05 g/min. The beginning of the energy supply of exogenous glucose could be determined quite soon after oral administration.
Sixty patients with stable knees and arthroscopic menisectomy were matched into two groups according to the presence of early degenerative changes at the operation. Patients with severe cartilage changes were excluded. The patients were between 20 and 40 years of age at the operation and no patient had previous surgery on the involved knee. The intraarticular findings were documented at surgery and the patients were re-examined 12 to 15 years after the meniscectomy. Pre-existing cartilage fibrillation at the meniscectomy did not seem to influence the long-term results. At the follow-up no difference was found between the groups at the physical examination, in subjective complaints, in knee function and activity or in radiographic findings. In the total group 62% had early signs of arthrosis (Fairbank changes) and 42% narrowing of the joint space (Ahlbäck grade 1-2) in the operated knee. No one had more severe changes. Radiographic signs of arthrosis were 4 times commoner in the operated knee compared to the non-operated knee after partial meniscectomy and 7 times commoner in the operated knee after subtotal meniscectomy. Arthrosis at the follow-up was seen three times more often in patients older than 30 years of age at surgery than in younger patients. The functional outcome was good and 70% were still active in sports compared to 90% before the operation.
Maximal oxygen uptake (V̇O2max) was measured on a treadmill in 375 teenagers, 13 and 14 years old.
V̇O2max per kg body mass in boys had a mean value of 59 ml.min⁻¹.kg⁻¹ and in girls of 51 ml.min⁻¹.kg⁻¹.
Linear regression analysis across biologic age revealed that in boys as well as in girls the V̇O2max increased with increasing biologic age. However, per kg body weight or per kg lean body mass V̇O2max decreased. V̇O2max per cm height squared and per kg body mass to the two-thirds power did not show a change with biologic age.
Multiple regression analysis revealed that the increase in the absolute values of the V̇O2max and the decrease in the relative values of the V̇O2max with increasing biologic age was almost completely due to the increase in total body mass (i.e. height and weight).
The purpose of this study was to compare the oxidation rate of ingested glucose during prolonged exercise, without and with the addition of sodium to the solution. The effect of metoclopramide, a drug which favors gastric emptying, was also investigated since gastric emptying could be a factor limiting the bioavailability of ingested glucose. Six subjects performed four bouts of exercise of 2 hours each at 64 +/- 4% VO2max on a cycle ergometer during which they ingested 100 g of glucose enriched with 13C, without (trials 1 and 3) and with (trials 2 and 4) addition of 25 mmol.l(-1) of NaCl. The glucose solution was ingested in four equal volumes (175 ml containing 25 g of glucose) at 0, 30, 60 and 90 min of the exercise period. For the trials 3 and 4, the subjects were given 10 mg of metoclopramide orally 60 min before the beginning of exercise. The VO2, VCO2 and heart rate were similar in response to exercise between the four trials. No significant difference was observed between trials for the oxidation rates of ingested glucose during the first as well as the second hour of exercise. Over the 120 min of exercise, the amounts of exogenous glucose oxidized were 52.0 +/- 9.6, 54.3 +/- 10.9, 52.7 +/- 12.3 and 53.3 +/- 10.4 grams for trials 1 to 4, respectively. The contribution of exogenous glucose oxidation to the energy yield represented 13.0 +/- 1.8% without and 13.2 +/- 1.9% with addition of NaCl. The amounts of endogenous carbohydrate and fat oxidized were also similar in the four trials. These results suggest that neither the addition of NaCl to glucose solutions nor the ingestion of metoclopramide increases the contribution of the oxidation of ingested glucose to the total energy yield during prolonged exercise.
The present study was undertaken in order to evaluate the effect of an aerobic training programme on the maximal power (Pmax) developed during a short-term exercise test in prepubertal children. Thirty-three 10-11 year old boys and girls were investigated: 17 (TG) participated twice a week (1 h per session) in a 13-week running programme and 16 (CG) served as a control group. Pmax was measured during a force-velocity test conducted on a friction-loaded cycle ergometer. The force (Fopt) and velocity (Vopt) at which Pmax was obtained were determined. Lower limb muscle mass (LMM) was evaluated by means of dual X-ray absorptiometry. Following training, Pmax increased even when muscle mass change due to the growth process was taken into account (Pmax W: + 23 %, W x kg(-1) LMM: + 18%, p < 0.001). The increase in Fopt was principally responsible for such an improvement since no alteration was noticed for Vopt after training. As for Pmax, Fopt was still greater following training when LMM was taken into account (p < 0.01). Furthermore, no changes were noticed for CG for all variables evaluated during the anaerobic test after the study period. Differences between TG and CG regarding Pmax and Fopt were obtained after training only. In conclusion this study highlights the effectiveness of an aerobic training programme to improve the maximal power during short-term exercise in prepubertal children.
A shadow shield whole body counter with automated gamma spectrum analysis is used in the division of nuclear medicine for the measurement of whole body radioactivity. After the radioactive fall-out in Austria caused by the Chernobyl accident the instrument has been extensively utilized for the assessment of the radiation level in the general population.
In November of 1986 and 1987 the level of internal contamination with ¹³⁷Cs in high-performance athletes was compared with a group of subjects practicing little or no sports. It was found that significantly higher contents of ¹³⁷Cs were present in the athletes. Furthermore, it was found that within the groups of athletes male subjects had significantly higher internal ¹³⁷Cs contamination per kilogram of body mass than the female subjects. An explanation for this is the different nutrition and the higher relative muscle mass of the athletes.
One hundred and thirty eight knees of 124 patients with partial rupture of the patellar ligament were treated surgically after failure to heal them by conservative means. Ultrasonography was used to confirm the diagnosis in 45 knees, and when positive it had a good correlation with the operative findings. During surgery excision of the devitalized tissue in the patellar tendon was performed. Histologic examination of the removed tissue revealed degenerated, fibrotic tissue with neo-vascularization, and slight to moderate inflammation resembling devitalized tissue. The patients were re-examined 18.6 +/- 15.0 months post-operatively. Ninety-seven patients (111 knees = 80.4%) benefitted from the operation with excellent or good results. Thirteen knees had to be re-operated with more radical excision due to renewed symptoms. In conclusion, surgical excision of the devitalized tissues gives a good functional result in most of the cases in which non-operative treatment with rest and physical treatment has failed, helping the athlete to return to his pre-injury activities.
This study measured muscle glycogen during a 7-day carbohydrate loading protocol. Twenty healthy subjects (12 male, 8 female) performed 1 hr treadmill/toe-raise exercise immediately before a 3-day low carbohydrate (LoCHO) diet (20 % carbohydrate, 60 % fat, 20 % protein). On day 3 they repeated the exercise and began a 4-day high carbohydrate (HiCHO) diet (90 % carbohydrate, 2 % fat, 8 % protein). The order of administration of the diet was reversed in a subpopulation (n = 3). Interleaved natural abundance 13C/ 31P NMR spectra were obtained before and immediately after exercise, and each day during the controlled diets in order to determine concentrations of glycogen (GLY), glucose-6-phosphate (G6P), and muscle pH. Following exercise, muscle GLY and pH were reduced (p < 0.001) while muscle G6P was elevated (p </= 0.01). During the 3-day LoCHO diet, fasting concentrations of G6P were not different from resting levels. During the first 3 days of the HiCHO diet, resting G6P was elevated (p </= 0.05) compared to before the study. By the final day, muscle glycogen was 1.6-fold greater than before the protocol, while G6P had returned to baseline. Daily GLY and G6P were not affected by the order in which the diet was administered. We conclude that increased glucose transport/phosphorylation plays a role in muscle glycogen supercompensation.
Erythropoiesis is affected during deep saturation dives. The mechanism should be related to a downregulation of serum Erythropoietin (s-EPO) concentration or to a toxic effect of the hyperbaric hyperoxia. We evaluated s-EPO and other haematological parameters in 6 scuba divers before, during and after a 14-days guinness saturation dive (8-10 m). Athletes were breathing air at 1.8-2 ATA, under the control of a team of physicians. Serum parameters were measured before diving (T0) and: 7 days (T1), 14 days (T2) after the beginning of the dive and 2 h (T3) and 24 h (T4) after resurfacing. Hgb, and many other haematological parameters did not change whereas Ht, s-EPO, the ratio between s-EPO predicted and that observed and reticulocytes (absolute, percent) declined progressively from T0 to T3. At T4 a significant rise in s-EPO was observed. Hgb did not vary but erythropoiesis seemed to be affected as s-EPO and reticulocyte counts showed. All these changes were statistically significant. The experiment, conducted in realistic conditions of dive length, oxygen concentration and pressure, allows us to formulate some hypotheses about the role of prolonged hyperbarism on erythropoiesis. The s-EPO rise, 24 h after resurfacing, is clearly documented and related to the "Normobaric Oxygen Paradox". This evidence suggests interesting hypotheses for new clinical applications such as modulation of s-EPO production and Hgb content triggered by appropriate O2 administration in pre-surgical patients or in some anemic disease.
Adolescence is often viewed as a critical period for selection in youth soccer. The present study compared the characteristics of regionally selected and non-selected under-14 players (U-14) as a group and by position. Players were classified as local (n=69) and regional (n=45). Weight, height, skinfolds, functional capacities, soccer skills and goal orientation were measured and skeletal age was assessed with the Fels method. Factorial ANOVA was used to test the effect of selection, position and respective interaction terms, while discriminant analysis was used to identify the variables that contributed to selection. Selected players had an advanced maturity status (F=24.97, p<0.01), were heavier (F=30.67, p<0.01) and taller (F=35.07, p<0.01); performed better in explosive power (F=21.25, p<0.01), repeated sprints (F=20.04, p<0.01) and ball control (F=3.69, p<0.05); and were more ego oriented (F=13.29, p<0.01). The 2 competitive groups did not differ in agility, aerobic endurance, dribbling, shooting, passing, and task orientation. Position-related variation was negligible. The percentage of players who were correctly classified in the original groups was slightly lower when the analysis was performed for the total sample (86%) than by position (86-90%). Future research on talent identification and selection should adopt a multidimensional approach including variables related to the physiological, perceptual, cognitive and tactical demands.
The purpose of this study was to compare the effectiveness of three very short interval training sessions (15-15 s of hard and easier runs) run at an average velocity equal to the critical velocity to elicit VO2 max for more than 10 minutes. We hypothesized that the interval with the smallest amplitude (defined as the ratio between the difference in velocity between the hard and the easy run divided by the average velocity and multiplied by 100) would be the most efficient to elicit VO2 max for the longer time. The subjects were middle-aged runners (52 +/- 5 yr, VO2 max of 52.1 +/- 6 mL x min(-1) x kg(-1), vVO2 max of 15.9 +/- 1.8 km x h(-1), critical velocity of 85.6 +/- 1.2% vVO2 max) who were used to long slow distance-training rather than interval training. They performed three interval-training (IT) sessions on a synthetic track (400 m) whilst breathing through the COSMED K4b2 portable metabolic analyser. These three IT sessions were: A) 90-80% vVO2 max (for hard bouts and active recovery periods, respectively), the amplitude= (90-80/85) 100=11%, B) 100-70% vVO2 max amplitude=35%, and C) 60 x 110% vVO2 max amplitude = 59%. Interval training A and B allowed the athlete to spend twice the time at VO2 max (14 min vs. 7 min) compared to interval training C. Moreover, at the end of interval training A and B the runners had a lower blood lactate than after the procedure C (9 vs. 11 mmol x l(-1)). In conclusion, short interval-training of 15s-15s at 90-80 and 100-70% of vVO2 max proved to be the most efficient in stimulating the oxygen consumption to its highest level in healthy middle-aged long-distance runners used to doing only long slow distance-training.
Scuba diving is known to affect the rhino-pharyngo-tubaric district (RPT unit). The aim of the study was to document function modifications of the RPT unit in 6 Italian divers (3 men and 3 women) who lived for 14 days consecutively at a depth of 8-10 m, breathing air (21% oxygen) at a pressure ranging between 1.8 and 2 ATA. RPT and inner ear assessment were carried out before the dive (TIME 0) and 24 h (TIME 1) after resurfacing, in order to investigate diving-related RPT and inner ear alterations. Physical examination after resurfacing revealed: fungal external otitis, otoscopic findings consistent with middle ear barotraumas and rhinosinusitis. Rhino-manometry showed a remarkable increase in inspiratory nasal flow and a substantial decrease in nasal resistance. No epithelial cell disruption was retrieved comparing pre and post resurfacing samples. Post-diving tubaric dysfunction was found. Pure tone audiometry revealed a bilateral 40 dB HL hearing loss at 4 kHz in 1 diver. Relevant PTA functions did not seem to be affected by the experiment, no remarkable changes were found at the Sensory Organisation Test and at the Motor Control Test. The 14-day underwater period had a positive effect on nasal flows and resistances.
The aim of the study was to determine changes in body composition and physical fitness during military service. A prospective cohort study of 140 healthy male conscripts was conducted. We examined subject characteristics, aerobic performance and muscle strength, and assessed body composition using dual-energy X-ray absorptiometry (DEXA) three times. Conscripts' mean baseline weight (79.5 kg) decreased by 2 kg during the first 3 months, but increased by 0.9 kg during the second 3-month period (p<0.001). Fat mass measured by DEXA decreased by 3.2 kg during the first but increased by 0.8 kg during the second 3-month period (p<0.001). Throughout the 6-month study, an increase was seen in distance of 12-min run test (from 2 380 m to 2 530 m; p<0.001), and muscle strength score (from 6.5 to 9.5 p<0.001). Finnish military training seems to have beneficial effects on physical fitness. However, considering the relatively modest changes in body fat and physical fitness seen in conscripts with average BMIs at baseline, design of diverse training programmes for the varying baseline BMI levels are warranted to improve the physical fitness results.
We investigated the oxygen uptake response (V.O (2)) to a 1500-m test conducted using a competition race strategy. On an outdoor track, eleven middle-distance runners performed a test to determine V.O (2max), velocity associated with V.O (2max) (v-V.O (2max)) and a supramaximal 1500-m running test (each test at least two days apart). V.O (2max) response was measured with the use of a miniaturised telemetric gas exchange system (Cosmed, K4, Roma, Italy). The 1500-m running test was performed at a mean velocity of 107. 6 + 2 % v-V.O (2max). The maximal value of oxygen uptake recorded during the 1500-m test (V.O (2peak)) was reached by subjects at 75.9 + 7.5 s (mean + SD) (i.e., 459 +/- 59 m). The time to reach V.O (2max) (TV.O (2peak)) and the start velocity (200- to 400-m after the onset of the 1500 m) expressed in % v-V.O (2max) were negatively and significantly correlated (p < 0.05), but our results indicate that a fast start does not necessarily induce a good performance. These results suggest that V.O (2max) is reached by all the subjects at the onset of a simulated 1500-m running event and are therefore in contrast with previous results obtained during treadmill running.
The purpose of this study was to investigate whether track running specialisation could be associated with differences in the ability to exchange and remove lactate. Thirty-four male high-level runners were divided into two groups according to their speciality (100 - 400 m/800 - 1500 m). All performed a 1-min 25.2 km × h⁻¹ event, followed by a 90-min passive recovery to obtain individual blood lactate recovery curves which were fitted to a bi-exponential time function:
[La](t) = [La](0) + A1(1-e-γ1t) + A2(1-e-γ2t).
The velocity constant γ1 which denotes the ability to exchange lactate between the previously worked muscles and blood was higher (p < 0.001) in middle-distance runners than in sprint runners. The velocity constant γ2 which reflects the overall ability to remove lactate did not differ significantly between the two groups. γ1 was positively correlated with the best performance over 800 m achieved by 16 athletes during the outdoor track season following the protocol (r = 0.55, p < 0.05). In conclusion, the lactate exchange ability seems to play a role on the athlete's capacity to sustain exercise close to 2-min-duration and specifically to run 800 m.
The purpose of this investigation was to determine whether the concepts of critical velocity (CV) and anaerobic swimming capacity (ASC) could be used by coaches as a reliable index in order to monitor 1500-m Surface (SF) performances in Finswimming. Thirteen Finswimmers (6 males and 7 females, 24+/-6 years), members of the Japanese national team, were instructed to swim three different swimming distances (400-, 800-, and 1500-m) at maximal effort in a 50m long course swimming pool. CV and the ASC were calculated using 400-m and 800-m swim times. Mean height and body mass were 170.2 cm and 69.7 kg in male and 160.5 and 61.0 kg in female. A highly positive correlation was found between the CV and the mean velocity of 1500-m SF (V1500) (r=0.91, P<0.01), but no correlation was found between the ASC and V1500. (r=0.46, P=0.11). However, a high correlation was found between the ASC and the residual error of V1500, calculated from the relationship between V1500 and the CV (r=0.89, P<0.01). These results suggest that the CV is a useful method for evaluating 1500-m SF performance and an aerobic performance expressed as the CV contributes to 1500-m SF performance.
The importance of chronological age (CA) and skeletal age (SA) in explaining variation in somatic dimensions, and the independent contributions of CA, SA, stature (ST) and weight (WT) to variability in physical fitness were investigated in a sample of 6593 girls 6-16 years of age. Body dimensions included lengths, breadths, circumferences, skinfolds, and Heath-Carter somatotype, while fitness tests included measures of health- and performance-related fitness, and cardiovascular and lung functions. Age-specific correlations were calculated between SA and anthropometric dimensions, fitness tests and cardiovascular and lung functions, while age-specific stepwise multiple regressions were used to investigate the relative importance of SA, CA, ST and WT in explaining fitness and cardiovascular and lung functions. SA is most highly correlated with lengths and then with breadths, circumferences and skinfolds in this order. SA per se or in interaction with CA is the only significant predictor of somatic characteristics. Among fitness items, physical working capacity and static strength correlate highest with SA. Bent arm hang, leg lifts and sit-ups correlate negatively with SA but values are low, while all other components correlate at non-significant or low levels. Results of the multiple regression analysis indicate that, with few exceptions, CA, SA, ST and WT and their interactions explain less than 10% of the variance in most physical fitness items. However, for PWC, arm pull strength, and bent arm hang, the interaction terms explain between 12% and 67% of the variance.
Eight Norwegian boys with cystic fibrosis (CF) 16 years of age were included in a 5-year follow-up study. They underwent pulmonary function and bicycle exercise tests 2-16 times each. The individual's habitudinal level of physical exercise was registered by interviews and training diaries to study whether it could be correlated to the developments in lung function, peak oxygen uptake (peak V̇O2), and Shwachman score.
The boys were characterized by a large interindividual variation in both lung function, peak V̇O2, and Shwachman score at the first test in the study. Four boys trained regularly 3-9 h weekly, while the four others had no regular exercise. Two of the latter, who also had the lowest Shwachman scores, died during the study. The other two in the non-training group deteriorated significantly in clinical scores, lung function variables, and peak V̇O2 during the study period of 5 years. The four boys in the training group improved in lung function and peak V̇O2 in accordance with or even better than expected in healthy adolescent boys during the same growth period.
Even though the material is small, and several factors might influence the results, the study indicates that regular physical exercise has beneficial long-term effects on lung function, physical fitness, and Shwachman score in adolescent CF boys.
To investigate running activity, life-style, and endurance capacity of joggers, all competitors of a popular 16-km race were surveyed by questionnaire. The response rate was 83.6%, yielding a study population of 4358 male runners over age 16. In univariate analysis, there were significant associations between 16-km running time and weekly training distance (average of 1 year), weekly training frequency, body mass index (BMI), age, cigarette smoking, years of regular running, and frequency of alcohol cosumption. A multiple regression analysis provided six significant, independent predictors of 16-km time, explaining 47% of its variance: weekly training distance (standardized regression coefficient = -0.46), age (0.37), BMI (0.23), years of regular running (-0.19), weekly training frequency (-0.11), and cigarette smoking (0.10). Based on laboratory treadmill testing of a subsample of runners, 16-km running times were transformed into maximum aerobic capacities (VO2 max equivalents) for all competitors. In comparison with the general population, even the slowest 5% of the runners showed a higher endurance capacity than the age-specific population mean. Application of the multivariate regression model for an estimation of the overall impact of training and life-style on endurance capacity showed that the great difference in mean endurance levels between joggers and the general population could entirely be attributed to differences in running activity, BMI, and smoking. We conclude that the joggers investigated were, on average, not selected concerning biological predisposition and genetic endowment since their behavior alone explained their high average endurance capacity.
To examine the long-term association of leisure time physical activity (LTPA) and risk of death from coronary heart disease (CHD) and all-causes.
Data are from a prospective study of 12,138 middle-aged men at high risk for CHD participating in the MRFIT. Men were classified into deciles based on average min/d of LTPA reported at baseline, which were compared with cumulative CHD and all-cause mortality endpoints at the 16-year follow-up.
Men in the least-active decile of LTPA who averaged 4.9 min/d of LTPA (range 0 to .9 min/d) had excess age-adjusted mortality rates of 29% and 22% for CHD and all-causes, respectively, as compared to those in combined deciles 2 to 4, who averaged 22.7 min/d of predominantly light and moderate LTPA (range 10-36 min/d). No further decrement in mortality rates was noted in those in the higher declines of LTPA. These associations remained significant (P < 0.05) after proportional hazards adjustments for additional possible confounding variables.
These data suggest that a relatively small amount (10 to 36 min/d) of daily moderate intensity LTPA can significantly reduce premature mortality, particularly from CHD, in middle-aged and older men at high risk for CHD.
Differences in cycling performance have been observed in cyclists with similar VO2max values yet different lactate thresholds. The purpose of the current study was to compare a simulated 16.1-km cycling time trial, VO2max and related factors in cyclists who significantly varied in ventilatory threshold. From an original group of 18 category III or IV cyclists, two groups of 6 cyclists were formed based on ventilatory threshold values as high (77 +/- 4% of VO2max-Group H) or low (68 +/- 2.8% - Group L). VO2max and a 16.1-km time trial were completed on a Velodyne trainer. No significant difference (p > or = 0.05) was noted between groups in VO2max (Group H 4.00 +/- 0.281.min-1, Group L 4.15 +/- 0.671.min-1), however significant differences (p < or = 0.05) were found in ventilatory threshold and time trial scores. Group H completed the time trial in 16.29 +/- 2.08 min while Group L averaged 20.93 +/- 3.03 min. Group H completed the time trial 28% more quickly by working at a significantly higher percentage of VO2max, a higher power output and a faster pedal rate than Group L. From a battery of physiologic and body composition parameters, the ventilatory threshold expressed as VO2 (l.min-1) was the best predictor (r = -0.76) of time trial performance in the 12 cyclists. The findings of this study indicate that the ventilatory threshold was superior to VO2max in discerning performance differences in a 16.1-km cycling time trial, and was the best predictor of the simulated time trial performance.
This study measured the influence of the flavonoid quercetin on immune changes and incidence rates of upper respiratory tract infections in ultramarathoners competing in the 160-km Western States Endurance Run. Sixty-three runners were randomized to quercetin and placebo groups, and under double-blinded methods ingested 1000 mg/day quercetin for 3 wks before, during, and 2 wks after the race. Thirty-nine of the 63 subjects (n = 18 for quercetin, n = 21 for placebo) finished the race and provided blood and saliva samples the morning before the race and 15 - 30 min postrace. Upper respiratory tract infections were assessed during the week before and the 2-wk period after the race using an illness symptom checklist. Race times did not differ significantly between quercetin and placebo groups. Significant pre- to postrace decreases were measured for natural killer cells (43 %), granulocyte respiratory burst activity (55 %), and salivary IgA output (48 %), and increases for neutrophil (288 %) and monocyte (211 %) cell counts, with no significant group differences. Postrace illness rates did not differ between groups. In conclusion, quercetin supplementation for 3 wks before and 2 wks after the Western States Endurance Run had no effect on illness rates, perturbations in leukocyte subset counts, or decreases in granulocyte respiratory burst activity and salivary IgA.
This study compares body composition characteristics with performance among participants in a 161-km trail ultramarathon. Height, mass, and percent body fat from bioimpedance spectroscopy were measured on 72 starters (17 women, 55 men). Correlation analyses were used to compare body characteristics with finish time, and unpaired t-tests were used to compare characteristics of finishers with non-finishers. Mean (+/-SD) BMI (kg x m(-2)) was 24.8+/-2.7 (range 19.1-32.2) for the men and 21.2+/-2.1 (range 18.1-26.7) for the women. Among the three fastest runners, BMI values ranged from 22.1 to 23.4 for men and 21.5 to 22.9 for women. Mean (+/-SD) percent body fat values for men and women were 17+/-5 (range 5-35) and 21+/-6 (range 10-29) , and ranged from 6 to 14 and 14 to 27 among the fastest three men and women. There was a significant positive correlation (r(2)=0.23; p=0.0025) between percent body fat and finish time for men but not for women, and percent body fat values were lower for finishers than non-finishers for men (p=0.03) and women (p=0.04). We conclude that despite wide variations in BMI and percent body fat among ultramarathon participants, the faster men have lower percent body fat values than the slower men, and finishers have lower percent body fat values than non-finishers.
This report documents performance-related trends in 100-mile (161-km) ultramarathon running competitions in North America. A retrospective analysis of results from 1977 through 2008 revealed that annual finish rates increased initially and then plateaued by the early 1990s at nearly 60%. The fastest times were produced by the 30-39 year age group among the men and the 40-49 year age group for the women. Finish times of women improved relative to men through the 1980s, but were then stable over the past two decades with the fastest women running about 20% slower than the fastest men. Additionally, the average times of the fastest runners did not change over the past two decades for any age group for either sex. The percentage difference in finish times between the first and fifth place runners has remained lower (p<0.0001) for men than women, and has shown an upward trend (p=0.003) across time for men. It is concluded that increasing participation in 161-km ultramarathons in North America has not been associated with improvements in performance or depth of competition with the exception of the relative improvements in finish times for women compared with men that was evident through the 1980s.
The purpose of the present study was to examine the criterion-related validity of the sit-and-reach test (SRT) and the modified sit-and-reach test (MSRT) for estimating hamstring flexibility in children and adolescents as well as to determine whether the MSRT is more valid than the SRT. A total of 87 (45 boys and 42 girls) children (6-12 years old) and adolescents (13-17 years old) performed the SRT and the MSRT. Hamstring flexibility was measured with goniometry through the passive straight-leg raise test. Regression analysis was performed to study the association of SRT and MSRT with hamstring flexibility (criterion measure). The SRT was associated with hamstring flexibility in both children (beta=1.089, R (2)=0.281, p=0.001) and adolescents (beta=0.690, R (2)=0.333, p=0.004). The MSRT was also associated with hamstring flexibility in both children (beta=1.296, R (2)=0.298, p<0.001) and adolescents (beta=0.588, R (2)=0.243, p=0.027). It is concluded that the criterion-related validity of the SRT and the MSRT for estimating hamstring flexibility is weak. The present data do not support that the MSRT is a more valid method than the SRT in children and adolescents.
We assessed the criterion related validity of 1/2 mile run/walk (1/2MRW) test for estimating VO2peak in children aged 6-17 years. The criterion related validity of the Fernhall's equation in a sub-group of children aged 10-17 years was also examined. A total of 86 children completed a maximal graded treadmill test and the 1/2MRW test. The cohort was randomly divided into either validation (n=47) or a cross-validation (n=39) group. A regression equation was computed and assessed through several error measures, and the Bland and Altman method. There was no systematic bias in the validation group nor in the cross-validation group (P > 0.1). The root mean sum of squared errors (RMSE), and the percentage error were 6.5 ml/kg/min, and 13.9%, respectively. These figures were very similar in the cross-validation group. The new equation had a lower RMSE and percentage error than the Fernhall's Equation (6.2 vs. 19.7 ml/kg/min, and 16% vs. 50.4%, respectively, P<0.001). The Fernhall's equation showed a significant underestimation of VO2peak (18.1 ml/kg/min, P<0.001). In conclusion, the new regression equation is valid for estimating VO2peak from the 1/2MRW time, sex, and body mass index in healthy children aged 6-17 years, and is more accurate than Fernhall's equation in the sample studied.
A prospective study of acute injuries from sports and physical exercise was carried out during 1 year in a total population of a municipality with 31,620 inhabitants. Data on exposure were collected : the number of participants in each sport, the hours of participation, and number of weeks in the season per year. The number of injuries was used as numerator and the exposure data as denominator in a formula modified from Chambers for the calculation of population at risk in sports.
A total of 571 injuries occurred in 28 different sports: 65% of the injured were males. The majority of the injuries were from soccer: 50% of the males and 27% of the females. Incidence rates in 17 sports are presented. The ranking order differs, when calculating not only the number, but also the exposure. Ice hockey and handball were then found to have the highest risk followed by soccer. Team and contact sports on the whole had the highest rates in both genders. As a group, intercompany players had the highest rate, especially in soccer. The lowest rates were found in individual sports such as downhill skiing, horseback riding, racket sports, and running. Gymnastics, except in school physical education, had no injuries at all.
Sprains and strains were diagnosed in nearly half of the cases and the foot and ankle were the most frequent sites. Preventive measures are proposed.