Dissociation of peak vascular conductance and V(O2) max among highly trained athletes. (1/51)

Previously, a strong relationship has been found between whole body maximal aerobic power (VO(2 max)) and peak vascular conductance in the calf muscle (J. L. Reading, J. M. Goodman, M. J. Plyley, J. S. Floras, P. P. Liu, P. R. McLaughlin, and R. J. Shephard. J. Appl. Physiol. 74: 567-573, 1993; P. G. Snell, W. H. Martin, J. C. Buckley, and C. G. Blomqvist. J. Appl. Physiol. 62: 606-610, 1987), suggesting a matching between maximal exercise capacity and peripheral vasodilatory reserve across a broad range of aerobic power. In contrast, long-term training could alter this relationship because of the unique demands for muscle blood flow and cardiac output imposed by different types of training. In particular, the high local blood flows but relatively low cardiac output demand imposed by the type of resistance training used by bodybuilders may cause a relatively greater development in peripheral vascular reserve than in aerobic power. To examine this possibility, we studied the relationship between treadmill VO(2 max) and vascular conductance in the calf by using strain-gauge plethysmography after maximal ischemic plantar flexion exercise in 8 healthy sedentary subjects (HS) and 28 athletes. The athletes were further divided into three groups: 10 elite middle-distance runners (ER), 11 power athletes (PA), and 7 bodybuilders (BB). We found that both BB and ER deviate from the previously demonstrated relationship between VO(2 max) and vascular conductance. Specifically, for a given vascular conductance, BB had a lower VO(2 max), whereas ER had a higher VO(2 max) than did HS and PA. We conclude that the relationship between peak vascular conductance and aerobic power is altered in BB and ER because of training-specific effects on central vs. peripheral cardiovascular adaptation to local skeletal muscle metabolic demand.  (+info)

Red blood cell variables in highly trained pubescent athletes: a comparative analysis. (2/51)

BACKGROUND: A suboptimal haematological status has often been recorded in athletes involved in intensive physical activity. There have even been reports of "sports anaemia" associated with intensive physical exercise. However, studies on the effect of different types of exercise practiced over a long period of time on the red blood cell variables in pubescent athletes are very few. AIM: To assess the basic red blood cell variables in highly trained pubescent athletes from different sports and to compare the results with those for a control untrained group. Sex related differences in these variables were also assessed. METHODS: 876 highly trained athletes (559 boys and 317 girls) were included in the study. Their mean (SEM) age, weight, and duration of training were: 14.01 (0.06) years, 56.24 (0.52) kg, and 3.52 (0.07) years respectively. The control group consisted of 357 untrained subjects (171 boys and 186 girls) with mean (SEM) age and weight of 14.58 (0.09) years and 57.75 (0.67) kg. The group of athletes was divided into seven subgroups according to the sport practiced: athletics (105), swimming (107), rowing (230), wrestling (225), weight lifting (47), various team sports (92), and other sports (67). Venous blood samples were drawn from the cubital vein, and the red blood cell count, packed cell volume, haemoglobin concentration, and mean corpuscular volume were measured. Statistical indices were computed for each group and for each variable, and analysis of variance factorial analysis was performed to evaluate the statistical significance of the differences detected. RESULTS: The highly trained group was found to have lower red blood cell count, packed cell volume, and haemoglobin concentration (p<0.001) than the control untrained group (4.61 (0.01) x 10(12)/l v 4.75 (0.02) x 10(12)/l, 0.389 (0.001) v 0.404 (0.002) l/l, and 133.01 (0.38) v 139.9 (0.62) g/l respectively). These variables were lower for the boys of the trained group than for the boys of the control group (p<0.001), and similarly for the girls (p<0.001). The lowest red blood cell count, packed cell volume, and haemoglobin concentration were measured in blood samples from the boys of the swimming subgroup (4.54 (0.06) x 10(12)/l, 0.386 (0.006) l/l, and 129.38 (1.80) g/l respectively) and the rowing subgroup (4.66 (0.03) x 10(12)/l, 0.400 (0.003) l/l, and 136.21 (0.94) respectively). The same distribution was found for the girls: lowest in the rowing subgroup (4.32 (0.04) x 10(12)/l, 0.314 (0.003) l/l, and 124.27 (0.93) g/l) and the swimming subgroup (4.40 (0.05) x 10(12)/l, 0.375 (0.005) l/l, and 125.90 (1.30) g/l). No differences were found in the mean corpuscular volume. CONCLUSIONS: Continuous (more than one year) high intensity sports training (twice a day/five days a week) results in a decrease in the basic red blood cell variables in pubescent boys and girls, this being most pronounced in the submaximal sports.  (+info)

Weight-bearing exercise and markers of bone turnover in female athletes. (3/51)

Weight-bearing activity provides an osteogenic stimulus, while effects of swimming on bone are unclear. We evaluated bone mineral density (BMD) and markers of bone turnover in female athletes (n = 41, age 20.7 yr) comparing three impact groups, high impact (High, basketball and volleyball, n = 14), medium impact (Med, soccer and track, n = 13), and nonimpact (Non, swimming, n = 7), with sedentary age-matched controls (Con, n = 7). BMD was assessed by dual-energy X-ray absorptiometry at the lumbar spine, femoral neck (FN), Ward's triangle, and trochanter (TR); bone resorption estimated from urinary cross-linked N-telopeptides (NTx); and bone formation determined from serum osteocalcin. Adjusted BMD (g/cm; covariates: body mass index, weight, and calcium and calorie intake) was greater at the FN and TR in the High group (1.27 +/- 0.03 and 1.05 +/- 0.03) than in the Non (1.05 +/- 0.04 and 0.86 +/- 0.04) and Con (1.03 +/- 0.05 and 0.85 +/- 0.05) groups and greater at the TR in the Med group (1.01 +/- 0.03) than in the Non (0.86 +/- 0.04) and Con (0.85 +/- 0.05) groups. Total body BMD was higher in the High group (4.9 +/- 0.12) than in the Med (4.5 +/- 0.12), Non (4.2 +/- 0.14), and Con (4.1 +/- 0.17) groups and greater in the Med group than in the Non and Con groups. Bone formation was lower in the Non group (19.8 +/- 2.6) than in the High (30.6 +/- 3.0) and Med (32.9 +/- 1.9, P < or = 0.05) groups. No differences in a marker of bone resorption (NTx) were noted. This indicates that women who participate in impact sports such as volleyball and basketball had higher BMDs and bone formation values than female swimmers.  (+info)

Isokinetic dynamometry of knee flexors and extensors: comparative study among non-athletes, jumper athletes and runner athletes. (4/51)

Participation in intensive sports activities leads to muscular specializations that may generate alterations in involved articular forces and cause static (posture) and dynamic changes (alterations of articular stability, coordination, etc.). Prevention of injury requires specific functional muscular evaluation in all athletes and for any kind of sport. OBJECTIVE: To dynamically evaluate, through isokinetic tests, the peak torque, total work, and average power of the knee flexor and extensor muscles of jumper and runner athletes and compare them to those of a non-athletic population, evaluating dominance and balance between agonistic and antagonistic muscle groups. RESULTS: In the non-athlete group, we noted a higher asymmetry between the dominant and nondominant members. The jumpers had the highest values of the evaluated parameters of all groups, whereas parameters for the runners were intermediate between non-athletes and jumpers.  (+info)

Effects of physical training on cortical bone at midtibia assessed by peripheral QCT. (5/51)

Effects of long-term exercise on volumetric bone mineral density (vBMD), bone mineral content, bone geometric properties, and the strength indexes of bone were examined in a cross-sectional study of athletes and controls. Tibias of 25 jumpers (13 women), 30 swimmers (15 women), and 25 controls (15 women), aged 18-23 yr, were scanned at midsite by using peripheral quantitative computed tomography. The cortical vBMD of female athletes was lower than that of the controls (2.00 +/- 0.05, 1.90 +/- 0.08, and 1.92 +/- 0.12 g/cm3, respectively, for controls, swimmers, and jumpers). On the other hand, periosteal areas of male jumpers and female athletes were greater than that of controls (460 +/- 50, 483 +/- 46, and 512 +/- 55 mm2, respectively, for male controls, swimmers, and jumpers, and 283 +/- 52, 341 +/- 73, and 378 +/- 75 mm2, respectively, for female controls, swimmers, and jumpers). The endocortical area of female swimmers was greater than that of controls (103 +/- 29, 148 +/- 52, and 135 +/- 54 mm2, respectively, for controls, swimmers, and jumpers). The polar moment of inertia and strength strain index of male jumpers and female athletes were significantly greater than those of controls, except for the difference in strength strain index between male jumpers and controls. We conclude that the improvement of mechanical properties of young adult bone in response to long-term exercise is related to geometric adaptation and not to vBMD.  (+info)

Isolated dislocation of the proximal tibiofibular joint in a long jumper. (6/51)

Acute traumatic proximal tibiofibular joint dislocation is an exceedingly rare injury. This is a case report in a rare horizontal type joint variant, following a long jump injury. The diagnostic approach when this injury is suspected is described.  (+info)

A study of changes in the spine in weight lifters and other athletes. (7/51)

The present study was undertaken in sportsmen of those groups of sports activities where weight training exercises constitute a major part of the training. Two groups consisting of 25 weight-lifters and 25 track and field athletes were studied to find out the effect of sports activities and lifting weights on the spine. 84% weight-lifters and 72% track and field athletes suffered from varying abnormalities. Incidence of backache in 25 weight-lifters was 40% and in 25 track and field athletes 48%. Radiological changes were more common in weight-lifters (84%) than in athletes (72%). Reduction in lumbar lordosis was found in three cases (12%) in both the groups. Obtuse angle deformity of vertebral margins was found in 11 cases (44%) amongst weight-lifters and six cases (24%) amongst athletes. Osteophytic formation was found in six cases (24%) in weight-lifters and four cases (16%) in athletes. Schmorl's node were noticed in five cases (20%) amongst weight-lifters and seven cases (28%) amongst athletes. The incidences of spondylosis and Schmorl's node were found only in those cases who had been doing weight training exercises for more than four years.  (+info)

Physiological adaptations to soccer specific endurance training in professional youth soccer players. (8/51)

BACKGROUND: Improved oxygen uptake improves soccer performance as regards distance covered, involvements with the ball, and number of sprints. Large improvements in oxygen uptake have been shown using interval running. A similar physiological load arising from interval running could be obtained using the soccer ball in training. OBJECTIVES: The main aim was to study physiological adaptations to a 10 week high intensity aerobic interval training program performed by professional youth soccer players, using a soccer specific ball dribbling track. METHODS: Eleven youth soccer players with a mean (SD) age of 16.9 (0.4) years performed high intensity aerobic interval training sessions twice per week for 10 weeks in addition to normal soccer training. The specific aerobic training consisted of four sets of 4 min work periods dribbling a soccer ball around a specially designed track at 90-95% of maximal heart frequency, with a 3 min recovery jog at 70% of maximal heart frequency between intervals. RESULTS: Mean VO2max improved significantly from 63.4 (5.6) to 69.8 (6.6) ml kg(-1) min(-1), or 183.3 (13.2) to 201.5 (16.2) ml kg(-0.75) min(-1) (p<0.001). Squat jump and counter movement jump height increased significantly from 37.7 (6.2) to 40.3 (6.1) cm and 52.0 (4.0) to 53.4 (4.2) cm, respectively (p<0.05). No significant changes in body mass, running economy, rate of force development, or 10 m sprint times occurred. CONCLUSION: Performing high intensity 4 min intervals dribbling a soccer ball around a specially designed track together with regular soccer training is effective for improving the VO2max of soccer players, with no negative interference effects on strength, jumping ability, and sprinting performance.  (+info)