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Objective: This study investigated the blood lactate accumulation during two wheelchair-racing protocols. During exercise, energy is required, which causes metabolism to increase and blood lactate to accumulate. Proper training can reduce the amount of blood lactate accumulation and increase tolerance to blood lactate accumulation during aerobic exercise., Methods: Eleven male wheelchair elite track athletes with a spinal cord injury were tested to determine their blood lactate response to speed and resistance workouts. A computer-monitored wheelchair dynamometer was used during all exercise tests. The order of the test (e.g., speed or resistance workout) was randomized. Blood pressure and blood samples were taken immediately before and after completion of each exercise test., Results: The difference between the blood lactate concentrations before and after testing were 8.56 +/- 4.42, and 11.67 +/- 4.69 mM for the resistance and speed tests, respectively., Conclusions: Our results showed that the blood lactate responses were significantly different for the resistance and speed workouts.

As a result of the improved medical treatment of infectious diseases, these formerly leading causes of mortality in the United States have been supplanted in rank by chronic events as the major causes of death. The major causes include coronary artery disease, respiratory disease, and cancer. Static and dynamic pulmonary functions in the apparently healthy wheelchair user population were measured and then modelled using stepwise regression. One hundred and nine wheelchair users (97 males, 12 females) with paraplegia (n = 77) or quadriplegia (n = 32) gave informed consent and participated in this study. Subjects ranged from being Olympic caliber wheelchair marathon racers to those who live sedentary life styles. Subjects performed three slow vital capacity (SVC) tests, three forced vital capacity (FVC) tests, and three maximal voluntary ventilation (MVV) tests while seated in their standard wheelchair. The order of the pulmonary function tests was randomized. Subjects also completed two functional residual capacity (FRC) measurements. Analysis of variance revealed significant differences in several pulmonary functions based on gender (FEVC, p = 0.0001, FEV1, p = 0.0001, FEVC 25-75%, p = 0.005, PEF, p = 0.002, FIVC, p = 0.002, RV, p = 0.0001, MVV, p = 0.0001, SVC, p = 0.001). The women's unforced prediction equations using age, height, weight did yield some significant correlations with predictions based upon ambulatory subjects. The men's unforced adapted prediction equations did reveal significant correlations with the validation group for FEVC (r = 0.66, p = 0.007), FEV1 (r = 0.62, p = 0.015), PIF (r = 0.95, p = 0.015), MVV (r = 0.57, p = 0.067), SVC (r = 0.69, p = 0.019), and RV (r = 0.67, p = 0.009). Pulmonary function in male wheelchair users should be predicted using equations which incorporate years with disability and level of impairment. Additional study is required to make any recommendations regarding women wheelchair users. However, study of pulmonary function in women should be made a priority. Pulmonary function is affected by the extent of physical impairment, and tends to decline as years with disability increase.

To determine the influence of varying doses of smokeless tobacco (moist snuff) on resting heart rate and blood pressure and the performance of brief, high-intensity exercise, 12 snuff users were examined at rest and while performing Wingate Anaerobic Tests after taking six different doses of snuff. Snuff caused an increase in heart rate; the larger the dose, the larger the response. Increases in systolic and diastolic blood pressure also occurred but were similar at all doses. Performance of brief, high-intensity exercise was unaffected, so that there was no benefit for such activities (e.g., sprinting bases in base ball).

Data from two studies were analyzed to quantify intraindividual variability and reliability in running economy (RE) and mechanics. Following 30-60 min of treadmill accommodation, stride-to-stride and day-to-day biomechanical stability were assessed in 31 male runners (studies 1 and 2) who performed two level treadmill runs (3.33 m.s-1) at the same time of day, in the same footwear, and in a nonfatigued state. Under the same testing conditions, daily stability in RE was determined in 17 of the 31 subjects (study 2). RE demonstrated high day-to-day reliability (r = 0.95), and the mean coefficient of variation in RE was 1.32% (range = 0.30-4.40%). Stride-to-stride reliability for temporal (T), kinematic (KNM), and kinetic (KIN) measures was very high (mean r = 0.96; range = 0.91-0.99), but day-to-day reliability was lower for KIN (mean r = 0.67; range = 0.28-0.88) compared with T and KNM (mean r = 0.91; range = 0.68-0.98). Further analyses revealed no significant (P less than or equal to 0.05) mean stride-to-stride differences for any biomechanical variable, and only three of 22 variables (peak resultant velocity of the ankle joint, step length, and swing time) demonstrated statistically significant day-to-day differences. Viewed in concert, these results suggest that, if the testing environment is controlled, multiple trials are not required to obtain stable measures of running economy and basic mechanical characteristics in trained male runners if group data from adequate sample sizes are considered. However, if individual records are scrutinized or if small sample sizes cannot be avoided, at least two measures of individual performances should be secured.

The purpose of this study was to document the effects of a prolonged (30 min) maximal run (PMR) on running economy (RE) and running mechanics in 16 male runners (mean VO2max = 59.0 +/- 4.5 ml.kg-1.min-1). After completing 60 min of treadmill accommodation, each subject performed two 10 min economy runs at 200 m.min-1. Subjects were also filmed at 100 fps during the last 30 s of each run in order to quantify 20 temporal, kinematic, and kinetic gait descriptors previously associated with RE variation. Following the second run, each subject completed the PMR at 85% of his predicted velocity at VO2max (89% VO2max). One, two, and four days after the PMR, subjects repeated the 10 min economy run. No significant difference (P greater than or equal to 0.05) in RE (range = 42.3-42.6 ml.kg-1.min-1) was observed following the PMR. Biomechanical analyses also indicated that, with the exception of one variable (plantar flexion angle at toe-off), gait characteristics remained unaltered after the PMR. When considered from a cross-disciplinary perspective, these data suggest that a 30 min maximal run does not increase the aerobic demand of running or disrupt the running mechanics of moderately trained male subjects who perform subsequent submaximal runs over the short term.

While the use of anabolic-androgenic steroids appears to be increasing, little is known about the long-term effects of these drugs. This study compared selected blood profiles of current and former steroid-using athletes to expected values for non-drug-using populations. The results are consistent with previous research findings that steroids can have acute negative effects on liver function, lipoprotein fractions, and testosterone production. The results suggest that side effects vary widely among individuals and are drug and dose dependent. Normal function appears to return after drug use is discontinued. These data emphasize the difficulty physicians have interpreting clinical tests when dealing with those who use or have used anabolic steroids. Clearly more research is needed regarding the effects of these drugs.

Previous research (study 1) has shown that a significant relationship exists between 10 km run time (RT) and predicted running velocity at VO2max (vVO2max) among well-trained males heterogeneous in VO2max. Since competitive runners often display a homogeneous fitness profile, the purpose of this study was to determine the association between 10 km RT and vVO2max among a group of trained runners exhibiting nearly identical VO2max values (study 2). Running economy (RE), vVO2max, and velocity at a 4 mM blood lactate concentration (v at 4 mM BL) were calculated in both studies. Correlations were obtained as shown in Table 2. The relationship between VO2max and 10 km RT achieved statistical significance only in study 1, while RE explained a greater amount of performance variation in study 2. In both studies, variation in 10 km RT attributable to vVO2max was similar and exceeded that due to either VO2max or RE. vVO2max also accounted for essentially the same amount of variation in 10 km RT as did v at 4 mM BL. It was concluded that, among well-trained subjects homogeneous in VO2max, a strong relationship exists between 10 km RT and vVO2max that appears to be mediated to a large extent by RE.