No description available.

Introduction. There is ample evidence that using carbohydrates during physical exercise contributes to increasing the duration of the physical load being experIenced. Still research devoted to the study of using carbohydrate solutions of different concentrations and in different quantities is of great interest. No definite results as to the time of assimilation of carbohydrates in respect to the starting point of the physical load undertaken are available either. Carbohydrates are the main source of energy during intensive exercise. The body of the athlete requires a greater amount of carbohydrates since they present in themselves the most efficient source of energy that prolongs muscle function by providing possibilities for the energy to be generated both aerobically and anaerobically. The topicality of the present study lies in the fact that it is aimed at establishing the effect of different solutions on the working capacity of athletes. The hypotesis of the research is: the assimilation of extra glucose 20 min after the start of running helps to prolong the duration of running. The aim of the research done was to establish the effect of using glucose during running on the duration of running possible. Subjects and methods. The subjects were seven long – distance runners (age 23.0 ± 1.9 years, height 1.82 ± 2.7 m, weight 77.0 ± 7.85 kg and body mass index 23.79 ± 2.06 kg/m2). Information as to health condition of the subjects, their physical activity and nutrition was... [to full text]

The purpose of this study was to examine the vertical component of the American College of Sports Medicine (A.C.S.M.) Guidelines equation to predict the oxygen cost of grade running. The A.C.S.M. Guidelines equation is: VO$ sb2$(ml/kg.min) = 3.5 + 0.2 speed(m/min) + 0.9 (speed(m/min) * grade(frac)). Twenty-three female runners (20 to 33 years) participated in (1) a VO$ sb2$max test, (2) five 6 min running economy (RE) tests at 133 m/min, (3) five 6 min RE tests at 160 m/min, and (4) three 6 min RE tests at 186 m/min. The RE tests at 133 and 160 m/min were performed at the following grades: 0, 2.5, 5.0, 7.5, and 10.0%. The RE tests at 186 m/min were performed at 0, 2.5, and 5.0% grade. The RE tests were administered in random order. There was a linear relationship between VO$ sb2$ and horizontal running velocity with a slope of 0.20 ml/kg.m (r = 0.996; p $<$.01). There was a linear relationship between VO$ sb2$ and percent grade when running on a treadmill. The correlations for the regression equations at speeds of 133, 160, and 186 m/min were 0.90 (p $<$.01), 0.86 (p $<$.01), and 0.73 (p $<$.01), respectively. Inclusion of a grade component in the regression analysis equation increased the accuracy for predicting the VO$ sb2$ of grade running. VO$ sb2$ consumption for grade running can be predicted using the following equation: VO$ sb2$ (ml/kg.min) = 3.5 + 0.198(speed in m/min + 0.932 grade(%)) + 0.006(speed(m/min) * grade(%)). The new equation explained 99.5% of the variance (R$ sp2$) compared to the 78.0% of the variance (R$ sp2$) that was explained by the A.C.S.M. Guidelines equation.

Spinal adaptive response in the frontal plane was investigated in relationship to pelvic unleveling during gait. Kinematic data were collected from 10 healthy adult subjects (5 male, 5 female) for walking and running on the treadmill at self-selected speeds. Spine and pelvic kinematic patterns and ranges of motion (ROM) were investigated with gender, speed and slope as factors. Speed and slope had the greatest impact on changes in the amplitude of the spine's kinematic patterns. Interaction effects were seen for speed and slope for the ROM, particularly of the greater trochanter (p < .047), PSIS (p < .011) and for the shoulders (p < 0.077). Gender presented more changes in the pelvic kinematics than the spine's kinematics. A significant trend in the females of greater ROM for T8 with increases in speed and slope was shown (p < 0.001). From this study it was concluded that speed, slope and gender were significant factors that affect the spine's ability to adapt to pelvic unleveling. In all conditions there was a coupled relationship found between the thoracic spine, lumbar spine and pelvis. In particular there was an oppositional movement found within the spine such that as the lumbar spine had convexity towards the swing leg then the thoracic spine had the opposite convexity. Hence, these factors are important when assessing posture and biomechanics of running and walking.

Background: The homeopathic preparation, Traumeel S, has been used as a valuable alternative to conventional non-steroidal anti-inflammatory drugs (NSAIDS) for over 30 years. This antihomotoxic, anti-phlogistic drug has been widely used by sportsmen and women in the treatment of lesions and inflammatory processes which result from exercise-induced skeletal muscle microtrauma. Although numerous randomised, double-blind placebo-controlled trials have confirmed the efficacy of Traumeel S as an anti-inflammatory agent, there are few in vivo studies which have specifically investigated the mechanism by which Traumeel S is effective in reducing inflammatory response to exercise-induced muscle cell damage. Aim: To establish whether the administration of Traumeel S during the five days before participation and three days following participation, significantly attenuates the systemic markers of the inflammatory response, following a 90-minute downhill running trial. Method: Twenty-four healthy athletes (14 men and 10 women), aged 20-50 years, were recruited for this study. Following baseline laboratory testing and familiarisation with the treadmill as well as a field test, subjects were matched according to gender, BMI, training age, training status, peak performance and foot strike patterns and randomised into Traumeel (TRS) and Control (PLAC) groups in a placebo-controlled, double-blind design. One Traumeel S or Placebo tablet was ingested three times per day for five days prior to and three days following a 90-minute exercise trial on a downhill (-6% gradient) at 75% V02 max- Blood samples were collected prior to the 90-minute trial (PRE), immediately after the trial (IPE) and 24 hours (24 PE), 48 hours (48 PE) and 72 hours (72 PE) following the trial. Each subject was also requested to complete a training record prior to the trial and keep a record of the daily symptoms of delayed onset muscle soreness (DOMS) both at rest (general pain) and during walking (daily living). Full blood counts (FBC), serum creatine kinase (CK), lactate dehydrogenase (LDH) and Cortisol concentrations were measured using standard haematological laboratory procedures and serum C-Reactive Protein (CRP) was determined by immunoturbidimetric assay. Sandwich ELISA's were used to determine myeloperoxidase (MPO) and plasma interleukin-6 (IL-6) concentrations. All results obtained were adjusted for changes in plasma volume as calculated from the red blood cell indices. Results: Mean ± SD characteristics of the gender-matched subjects in the experimental (TRS) and placebo-control (PLAC) groups did not differ significantly in terms of BMI, age, % body fat, FVC, FEVi, training age and status, foot strike pattern or peak running performance, maximal Heart Rate, VE, V02peak> RER, RPE during the maximal exercise test (p > 0.05). This indicated that the randomised pairs were well matched. The 90-minute downhill running protocol resulted in significant elevations in total circulating white blood cell count (WBC), neutrophil, CK, LDH, Cortisol, CPR, MPO and IL-6 concentrations (p < 0.001). When comparing the TRS and PLAC groups, mean ± SD total and differential WBC count, neutrophil count, CK, LDH, Cortisol, CPR, MPO and IL-6 concentrations did not differ (p > 0.05) over the 5 time points. At 24 PE, MPO concentrations were significantly higher in the TRS group than in the PLAC group (p = 0.03). The lower mean ± SD post-trial DOMS scores reported by the TRS group were not significantly different from those reported by the PLAC group (p > 0.05). Conclusion: Although the findings of this study did not identify differences in circulating CK, LDH, Cortisol, CPR and IL-6 concentrations between the TRS and PLAC groups, the elevated MPO concentration at 24 PE did provide preliminary novel evidence of enhanced activation of neutrophil oxidative burst activity following exercise-induced muscle damage which is hypothesized to accelerate the recovery process. / Thesis (M.Med.Sc.)-University of KwaZulu-Natal, 2008.

The interaction between exercise and cognitive task performance has been previously examined using cycle ergometer and treadmill running tasks. The interaction between natural (non-constrained) exercise and cognitive task performance has, however, been well less examined. An example of a natural exercise task would be running outdoors on a steep trail where route selection and foot placement are critical for the runner. The performance of runners is examined in a dual trail-running and working memory task. The working memory task involved counting tones, and was performed at both a low workload, in which they were asked to count every fourth low frequency tone and a high workload in which they were asked to count every fourth low, medium and high frequency tone. In experiment 1, runners performed the tone-counting tasks both while running on a steep trail with uneven terrain and while seated (control conditions). In addition, they ran the trail without a cognitive task load. Running distance and counting accuracy significantly decreased during the dual task trials, there was a linear trend the run distance decreased as the task got harder. As the secondary cognitive task demand increased running performance decreased (linear trend). Cognitive performance was only significantly impaired while running for the hard cognitive task (for the easy cognitive task there was no statistically significant difference). Participants reported an increased workload in the dual run-counting task conditions when compared with the seated task conditions. Reports of task focus and feeling of being spent (exhausted) also varied across task conditions. In experiment 2 unconstrained running was conducted in the same manner, on a flat-even terrain track to establish if the route selection and scanning required to negotiate uneven terrain was causing the dual-task interference, or if there is a general interference effect caused by the self-regulatory demands of running, or the direct demands of running itself (exercise). The linear trend of decreased running performance with increased secondary cognitive demand was similar to experiment 1 - the more cognitive load the less distance traveled. The effect on the cognitive task was, however, not evident in experiment 2; there was no statistically significant difference between cognitive task performance in the dual and single-task conditions. The findings outlined in these experiments, demonstrate dual cognitive tasks have a negative effect on running performance, and the cognitive task may also be affected depending on running intensity, particularly where self-paced natural running over terrain is coupled with complex cognitive tasks.

The purpose of this study was to determine whether adherance to a modified vegetarian diet predisposed young female athletes to iron deficiency. Two groups of female distance runners volunteered to be subjects for this study. One group consisted of women who regularly consumed red meat, and the other groups women who consumed a modified vegetarian diet. Three day dietary records analyzed to estimate nutrient intake, including available iron. Measures of serum ferritin, serum iron, total iron binding capacity, percent transferrin saturation, hemoglobin and hematocrit were done to asses iron status. The two groups did not differ in the amount of total iron or available iron in their diets. The red meat eating subjects consumed significantly more heme iron from their diets than the modified vegetarians; however there were no differences between the two groups in any of the measures of hematological or iron status. While there were no differences between the two groups in the percent of subjects classified in each stage, 37% of all of the subjects were classified as having a stage 1 deficiency, associated with iron deficient stores, and 11% of the subjects were classified as having a stage 2 deficiency, indicating iron deficient erythropoiesis. None of the subjects were anemic. The results indicate that adherance to a modifed vegetarian diet in this age group did not increase the risk of iron deficiency. / School of Physical Education

Six runners (V02 max=68.2 ± 3.4 ml/kg/min) were studied on three separate occasions during a 30 min treadmill run at 70% V02 max. On each occasion, the subjects ingested either 75g of glucose (trial G), fructose (trial F) or a sweetened placebo (trial C). No differences were observed between any of the trials for oxygen uptake, heart rate or perceived exertion. Serum glucose levels were elevated as a result of the glucose feeding (P<0.05) reaching peak levels at 30 min post-feeding. With the onset of exercise, glucose levels dropped to a low of 5.89 ± 0.99 mmol/l at 15 min of exercise in trial G. Serum glucose concentrations in trials F and C averaged 6.21 ± 0.31 mmol/l and 5.95 ± 0.23 mmol/l over all the time points, respectively, and were not different (p>0.05). Muscle glycogen utilization in the first 15 min of exercise was similar in trial C (18.8 ± 1.9 mmol/kg), trial F (16.3 ± 4.1 mmol/kg) and trial G (18.8 ± 9.1 mmol/kg), and total glycogen use was also similar in trial C (20.7 ± 5.3 mmol/kg), trial F (35.4 ±6.3 mmol/kg) and trial G (25.6 ± mmol/kg). These data suggest that pre-exercise feedings of fructose or glucose do not affect the rate of muscle glycogen utilization during 30 min of treadmill running in well-trained runners.

The assessment of physical activity is of great interest to the public and to researchers. One of the most popular and objective methods of assessing physical activity is using motion sensors such as pedometers and accelerometers. The purpose of this study was to assess the accuracy and reliability of step counting and energy expenditure estimation of two popular electronic pedometers and one accelerometer during running. In all step-counting trials, actual step counts were determined using a hand tally counter. Twenty subjects (18-40 years) were asked to volunteer to participate in the study. During the initial assessment subjects ran at five, six, seven, and eight miles per hour on a motor driven treadmill for ten minutes at each speed. While running they wore two pedometers and an accelerometer while oxygen consumption was measured. In the second assessment, all subjects ran a timed, self-paced mile around a 200-meter track while wearing all three activity monitors. In the third assessment, thirteen subjects ran at five, six, seven and eight miles per hour on a motor driven treadmill for three minutes at each speed to assess the step counting reliability of the devices. The three devices were accurate to within 1% at all speeds on the treadmill and on the self-paced track run. In addition, all three devices were reliable (r = 0.80). Caloric expenditure estimation accuracy the NL-2000 was ± 21% when expressed in both net and gross kcals. The Digi-walker was f 22% when assumed to be net kcals and ± 45% when assumed to be gross kcals. The Actigraph was accurate to ± 49% in terms of net calories. The results of the current study have shown that these devices are accurate and reliable for step counting at speeds between five and eight mph. However, their ability to assess caloric expenditure is not accurate at the same speeds. In conclusion, the application of these devices to runners is limited to highly accurate and reliable step counters. / School of Physical Education, Sport, and Exercise Science

The purpose of this investigation was to examine the contractile properties of individual slow and fast myofibers in response to various training periods throughout a collegiate cross-country season in male runners. Muscle biopsies were obtained from the gastrocnemius of five runners at three time points during the season; after a summer aerobic training phase (T1); after an 8 week period of intense training (T2) and after a 4 week taper period (T3). Absolute (4.6±0.3 L/min) and relative (71±0.7 mI/kg/min) maximal oxygen consumption were unchanged during the study duration. Run performance (8 km) improved 3% from T1 to T2 (27:26 to 26:38 min:sec) and 1% from T2 to T3 (26:21 min:sec). A total of 328 individual myofibers were isolated and studied at 15°C. MHC I diameter was 3% lower (P < 0.05) at T2 compared to T1 and 4% smaller at T3 compared to T2. MHC I and Ila fibers were 18 and 11 % stronger (P < 0.05) respectively, from T1 to T2. MHC I fibers produced 9% less force (P < 0.05) after the taper (T2-T3) while MHC Ila fibers were 9% stronger (P < 0.05). Specific tension (Po/CSA) increased (P < 0.05) 38 and 26% for MHC I and Ila fibers, respectively from T1 to T2 and was unchanged with the taper. Maximal shortening velocity (Vo) of the MHC I fibers decreased (P < 0.05) 23% from T1 to T2 and 17% from T2 to T3. MHC I peak power decreased (P < 0.05) 20% from T1 to T2 and 25% from T2 to T3. Power corrected for cell size decreased (P < 0.05) 15% from T2 to T3 and was 24% lower at T3 compared to T1 for the MHC I fibers only. MHC Ila diameter, Vo, peak and normalized power were unaltered during the study duration. These data suggest that myocellular function is sensitive to changes in run training and it appears that MHC I fibers are moreaffected than MHC IIa fibers. Furthermore, the increase in interval training with the taper may have offset the modest reduction in training volume and prevented any positive adaptations at the cellular level. / Human Performance Laboratory