Respiratory responses of elite oarsmen,former oarsmen,and highly trained non-rowers during rowing,cycling and running

The position of the body and use of the respiratory muscles in the act of rowing may limit ventilation and thereby reduce maximal aerobic power relative to that achieved in cycling or running, in spite of the greater muscle mass involved in rowing. This hypothesis was investigated for three groups of male subjects: nine elite senior oarsmen, eight former senior oarsmen and eight highly trained athletes unskilled in rowing. The subjects performed graded exercise to maximal effort on a rowing ergometer, cycle ergometer and treadmill while respiratory minute volume and oxygen consumption were monitored continuously. The VE at a given during intense submaximal exercise (greater than 75% of maximal ) was not significantly lower in rowing compared with that in cycling and treadmill running for any group, which would suggest that submaximal rowing does not restrict ventilation. At maximal effort, and for rowing were less than those for the other types of exercise in all the groups, although the differences were not statistically significant in the elite oarsmen. These data are consistent with a ventilatory limitation to maximal performance in rowing that may have been partly overcome by training in the elite oarsmen. Alternatively, a lower maximal VE in rowing might have been an effect rather than a cause of a lower maximal if maximal was limited by the lower rate of muscle activation in rowing.     

Glucose,insulin and lipid parameters in 10,000 m running

Summary Thirteen conditioned athletes were studied before and 5 min after running 10,000 m. This distance was run in an average of 41±4 min. All runners lost weight and accompanying this weight loss was an increase in the serum osmolality in the six runners in which it was measured. There was a significant increase in serum glucose (96±11 mg-% before run; 170±48 mg-% after run) and this increase was inversely correlated with running time. There was also a small, but significant, increase in serum insulin (15±2 U/ml before run; 19±4 U/ml after run). There was no consistent effect of running 10,000 m on serum cholesterol and triglyceride levels and on plasma lipoprotein electrophoresis patterns.     

Acute changes in muscle activation and leg extension performance after different running exercises in elite long distance runners

This study investigated acute changes in muscle activation and muscular power performance after three different running exercises in elite long-distance runners. Twenty-two nationally and internationally ranked long-distance runners performed first an incremental treadmill running test until exhaustion (MR) and then 40 min continuous (TR) and intermittent (2 min run/2 min rest) (IR) running exercises at an intensity of 80 and 100% of the velocity associated with VO_2max, respectively. Muscle activation and muscular power performance tests (counter-movement jumps, CMJ, and a set of ten maximal half squats from the static starting position with an extra load of 35% of the subjects,′ one repetition maximum) were performed before and immediately after the runs. The average mechanical power (P) of the half squats was calculated and the root mean square electromyogram (EMGrms) from the vastus lateralis, vastus medialis, gastrocnemius and biceps femoris muscles was recorded simultaneously during the half squat performances. The results showed an acute exercise–induced increase in P (ANOVA time effect, P=0.000) together with a reduction in EMGrms of the knee extensor muscles (ANOVA time effect, P=0.000). However, mechanical P expressed as a relative change within the set decreased after MR. In TR the improvement in P correlated positively with the maximal running performance of the runners (P<0.05), while in IR it correlated negatively (P<0.05). Jumping performance was significantly enhanced after each run (P<0.001, for all) and the improvement correlated negatively with the maximal sprinting speed and maximal jumping height of the runners (P<0.01, for all). It is concluded that in elite long distance runners an intensive prolonged running exercise reduces the surface EMG of the knee extensor muscles, and may lead to a different coordination strategy in leg extension exercises performed into the vertical direction. After continuous type of running the power improvement correlates positively with maximal endurance running capacity, whereas after intermittent type of running it correlates negatively.     

Metabolic responses to a 48-h ultra-marathon run in middle-aged male amateur runners

Purpose

To evaluate ongoing metabolic changes during a 48-h competitive run and a 48-h recovery period, with focus on potential health risks exemplified by heart and skeletal muscle damage biomarkers and oxidative stress-related indices.

Methods

Blood samples were taken before the race, after 12, 24, and 48 h of running, and after 24 and 48 h of recovery from male amateur runners (N = 7, age 35–59 years, VO_2max mean ± SD 57.0 ± 4.0 ml kg^?1 min^?1, total distance covered 183–320 km). The samples were analyzed for morphology, acid–base and electrolyte balance, iron status, lipid profile, interleukin-6, high-sensitivity C-reactive protein, N-terminal pro-brain-type natriuretic peptide, high-sensitivity cardiac troponin T, non-enzymatic antioxidants, activities of selected enzymes including antioxidant enzymes, and total antioxidant status.

Results

The sustained ultra-endurance run caused hypocapnic alkalosis with slight hyperkalemia and hypocalcemia, but no hyponatremia. Blood biochemistry showed severe muscle but not liver damage, and an acute inflammatory response. These effects were evidenced by leukocytosis, several fold rises in interleukin-6 and high sensitivity C-reactive protein, extreme elevations in serum levels of muscle enzymes, and marked increases in cardiac biomarker levels. Most of the changes dissolved during the 48 h post-race recovery. Neither the iron pool, nor erythropoiesis, nor pro-oxidant/antioxidant balance were substantially affected.

Conclusions

The changes consequent on the ultra-endurance run do not pose a serious health risk in men who begin their endeavor with ultra-endurance running in mid-life. There is some circumstantial evidence that hyperventilatory hypocapnia may modulate inflammatory response by stimulating the release of interleukin-6 from working skeletal muscles.     

Enhanced release of cytokines, interleukin-2 receptors, and neopterin after long-distance running.

This study was designed to examine cytokine production in a group of 22 well-trained runners covering a distance of 20 km within 2 hr. After running, all participants displayed a marked granulocytosis for 7 hr. Plasma neopterin levels increased 1 hr after exercise for 24 hr. Except for interleukin-6 (IL-6), cytokines were not reliably detected in plasma but were present in urine. Already before exercise, cytokines were detected in the urine of runners when compared to sedentary controls. Directly after running, interferon-gamma and tumor necrosis factor-alpha were further elevated but rapidly declined to preexercise levels. Interleukin-1 beta and interleukin-6 increased at a slower rate after exercise but secretion into urine persisted longer until 12 and 7 hr, respectively. Interleukin-2 (IL-2) was not detected but soluble IL-2 receptors appeared in the urine directly after running. Enhanced cytokine levels were accompanied by an only low creatinin kinase increase, indicating little muscle damage. These data show that long-distance running elevates cytokine production which supports the concept that regular, but not excessive, physical exercise may be beneficial by maintaining a stimulated immune system.     

The adaptation of myoglobin with age and training and its relationship to the three fiber types of skeletal muscle in miniature pig

Muscle biopsies were performed on 6 endurance and 6 sprint trained and 5 control miniature pigs after 3 and 7 months of training. The biopsied muscle was fixed, sectioned and stained for myoglobin. The darkest staining fibers were called dark fibers, the lightest staining were called light fibers and those of intermediate intensity were called moderate fibers. The distribution of the three fiber types, identified by myoglobin staining, did not change following either an endurance or sprint running regimen despite physiologically measured training effects. Myoglobin increased substantially with maturation as reflected by a significant increase in the number of dark myoglobin fibers in the biceps femoris at 11 compared to 7 months of age. It was suggested that the large increase in myoglobin content due to normal maturation may have obscured the differences among groups due to training. With enzyme histochemical analysis, dark myoglobin fibers were found to be slow red or fast intermediate fibers, but never fast white fibers. This relationship between myoglobin and the oxidative fibers (slow red and fast intermediate) supports the concept that myoglobin stores oxygen and aids its diffusion into muscle fibers in need of a constant oxygen supply.     

Effects of mechanical properties of muscle and tendon on performance in long distance runners

The purpose of this study was to investigate the mechanical properties of muscle and tendon in long distance runners and their relations to running performance. Fifteen long distance runners (LDR) and 21 untrained subjects (CON) participated in this study. Muscle strength and activation level of knee extensors and plantar flexors were measured. Tendon elongation was determined using ultrasonography, while subjects performed ramp isometric knee extension and plantar flexion up to the voluntary maximum. Relative MVC (to body mass) of LDR was significantly lower than that of CON for knee extensors, but not for plantar flexors. No significant difference in the neural activation levels was found between LDR and CON for both sites. Maximal tendon elongation of LDR was significantly lower than that of CON for knee extensors, but not for plantar flexors. Furthermore, faster running time in a 5,000 m race (best official record of LDR) was associated with lower tendon stiffness for both sites. In conclusion, the tendon of long distance runners is less extensible than those of untrained subjects for knee extensors, but not for plantar flexors. For both sites, however, the lower tendon stiffness may be in favor of the running performance in long distance runners.     

Aerobic capacity and fractional utilisation of aerobic capacity in elite and non-elite male and female marathon runners

Summary The physiology of marathon running has been extensively studied both in the laboratory and in the field, but these investigations have been confined to elite competitors. In the present study 28 competitors who took part in a marathon race (42.2 km) have been studied; 18 male subjects recorded times from 2 h 19 min 58 s to 4 h 53 min 23 s; 10 female subjects recorded times between 2 h 53 min 4 s and 5 h 16 min 1 s. Subjects visited the laboratory 2–3 weeks after the race and ran on a motor driven treadmill at a series of speeds and inclines; oxygen uptake O₂ was measured during running at average marathon racing pace. Maximum oxygen uptake ( O₂ max) was measured during uphill running. For both males (r=0.88) and females (r=0.63), linear relationships were found to exist between marathon performance and aerobic capacity. Similarly, the fraction of O₂ max which was sustained throughout the race was significantly correlated with performance for both male (r=0.74) and female (r=0.73) runners. The fastest runners were running at a speed requiring approximately 75% of O₂ max; for the slowest runners, the work load corresponded to approximately 60% of O₂ max. Correction of these estimates for the additional effort involved in overcoming air resistance, and in running on uneven terrain will substantially increase the oxygen requirement for the faster runners, while having a much smaller effect on the work rate of the slowest competitors. Five minutes of treadmill running at average racing pace at zero gradient did not result in marked elevation of the blood lactate concentration in any of the subjects.     

Cardiorespiratory response to treadmill and bicycle exercise in runners

Summary Maximal aerobic power and related variables during submaximal work were determined on the bicycle ergometer and on the treadmill in nine long-distance runners and in nine control subjects.During submaximal work, heart rate and pulmonary ventilation were similar with the two exercise procedures in each group, but the runners had lower values than the control subjects.During maximal exercise, oxygen uptake and pulmonary ventilation reached higher levels on the treadmill than on the bicycle ergometer. The difference in max was not significant in the control subjects (4.4%), but was more pronounced (12.8%) and highly significant (p<0.01) in the runners. The intergroup differences for max between runners and controls were more marked during treadmill running (17.3%) than during bicycle exercise (8.5%).It is concluded that the differences between the max values obtained on the bicycle ergometer and on the treadmill are influenced by the training conditions of the subjects and that bicycle ergometry leads to a marked underestimation of maximal oxygen uptake in runners.     

Runners in their forties dominate ultra-marathons from 50 to 3,100 miles

OBJECTIVES:

This study investigated performance trends and the age of peak running speed in ultra-marathons from 50 to 3,100 miles.

METHODS:

The running speed and age of the fastest competitors in 50-, 100-, 200-, 1,000- and 3,100-mile events held worldwide from 1971 to 2012 were analyzed using single- and multi-level regression analyses.

RESULTS:

The number of events and competitors increased exponentially in 50- and 100-mile events. For the annual fastest runners, women improved in 50-mile events, but not men. In 100-mile events, both women and men improved their performance. In 1,000-mile events, men became slower. For the annual top ten runners, women improved in 50- and 100-mile events, whereas the performance of men remained unchanged in 50- and 3,100-mile events but improved in 100-mile events. The age of the annual fastest runners was approximately 35 years for both women and men in 50-mile events and approximately 35 years for women in 100-mile events. For men, the age of the annual fastest runners in 100-mile events was higher at 38 years. For the annual fastest runners of 1,000-mile events, the women were approximately 43 years of age, whereas for men, the age increased to 48 years of age. For the annual fastest runners of 3,100-mile events, the age in women decreased to 35 years and was approximately 39 years in men.

CONCLUSION:

The running speed of the fastest competitors increased for both women and men in 100-mile events but only for women in 50-mile events. The age of peak running speed increased in men with increasing race distance to approximately 45 years in 1,000-mile events, whereas it decreased to approximately 39 years in 3,100-mile events. In women, the upper age of peak running speed increased to approximately 51 years in 3,100-mile events.     

Association between the angiotensin I-converting enzyme gene insertion/deletion polymorphism and endurance running speed in Japanese runners

We investigated the association between the angiotensin I-converting enzyme (ACE) gene insertion (I)/deletion (D) polymorphism and endurance running performance in Japanese elite runners, including several Olympic athletes. The frequency of the I/I genotype was not significantly higher and the frequency of the D/D genotype was not significantly lower in elite runners compared with non-athletes. However, the frequency of the I/D genotype tended to be lower in elite runners than in non-athletes. The best performance was significantly higher for runners with the D/D genotype than for those with the I/I genotype, and the average running speed was significantly higher for those with the combined D/D + I/D genotypes than for those with the I/I genotype. There were no I/I genotypes among the five fastest marathon runners. These results suggest that the D allele of the ACE gene I/D polymorphism is associated with a high level of human endurance.     

Metabolic adaptation to prolonged exercise

Summary A study was undertaken to evaluate and to examine the role of substrate supply in 50 healthy subjects after long distance events, such as 10 km, 25 km, and marathon races. The metabolic, variables of carbohydrate metabolism were greatest in 10-km runners, with the highest increase in glucose, lactate, and pyruvate, while in marathon runners only moderate changes were observed. Marathon competitors gave the greatest decrease in insulin concentration whereas glucagon and cortisol showed a contrary tendency. As for lipid concentrations, the most remarkable point was that after the marathon competition the best runners had the highest increase in free fatty acids; the longer the race, the higher were the -hydroxybutyrate and acetoacetate levels after the competition.It is important to emphasize that the limiting factor up to 90 min duration is the competitor's ability to deplete the stores of glycogen. Beyond 90 min (or 25 km) the decrease in insulin, the rise in cortisol and the higher concentration of ketnne bodies found indicate a change in metabnlic response.     

Determinants of performance in 1,500-m runners

Our aim was to investigate the relationship between physiological variables (not previously studied) and performance in elite 1,500-m runners. We assessed eight male athletes with an average personal best time of 233.3 ± 6.9 s (110% of the world record) for the 1,500-m race. Ventilatory measurements, maximal oxygen consumption $ (\dot{V}{\text{O}}_{{2{\max }}} ), Our aim was to investigate the relationship between physiological variables (not previously studied) and performance in elite 1,500-m runners. We assessed eight male athletes with an average personal best time of 233.3 ± 6.9 s (110% of the world record) for the 1,500-m race. Ventilatory measurements, maximal oxygen consumption VO2max maximal vastus lateralis muscle deoxygenation (?[deoxy(Hb+Mb)])max via near-infrared spectroscopy (NIRS), and maximal velocity (V (max)) were obtained during an incremental treadmill test. During subsequent constant-speed exercise at Vmax, we determined the time to exhaustion (Tlim), end-exercise blood lactate concentration ([La]b(max)), VO2 and ?[deoxy(Hb+Mb)] kinetics parameters. The mean VO2max, [La]b(max) and Vmax were 70.2 ± 3.9 mL kg(-1) min(-1), 12.7 ± 2.4 mmol L(-1), 21.5 ± 0.5 km h(-1), respectively. VO2 at Vmax showed a significant negative correlation with Tlim, whereas [La]b(max) was positively correlated with Tlim. Race speed was found to significantly correlate with ?[deoxy(Hb+Mb)](max) (79% of maximal value obtained during a transient limb ischemia), ?[deoxy(Hb+Mb)] slow component (22.9 ± 9.3% of total amplitude) and [La]b(max) at Vmax. [La]b(max) at Vmax was also significantly correlated with ?[deoxy(Hb+Mb)] slow component, suggesting a greater release of oxygen from the hemoglobin due to the Bohr effect. We conclude that both the maximal capacity of muscle to extract O2 from the blood and the end-exercise blood lactate accumulation are important predictors of best performance in 1,500-m runners.     

Physiological and metabolic effects of a 25 km race in female athletes

Summary Nine female athletes were examined before and after a 25 km race (German championship). Their average running speed was 3.89 m/s. Postexercise weight loss was 1.60±0.58 kg or 2.87% of body weight, the mean rectal temperature increased by 1.04±0.52 C to 38.4±0.54 C. Leucocytes, but no other blood parameters (hemoglobin, hematocrit, erythrocytes, MCV) showed a marked rise after the race. Blood lactate rose from 1.86±0.34 to 4.97±1.19 mmol/l but hypoglycemia was not present in any of the athletes at the end of exercise. After the run serum enzymes showed lower increases than those observed in men for the same exercise duration. Serum sodium, chloride and potassium showed similar increases, inorganic phosphate higher increments than found in men. The comparatively high rise in free glycerol suggested a marked mobilization of lipid substrate, whereas the increment in serum of free fatty acids was lower than in male subjects after similar athletic events.A lowering of neuromuscular excitability (m. vastus medialis quadricipitis) was found after the race but the changes were significant only for the fibers responding to longer durations of stimuli (0.3–30 ms).     

Value of the detection of myoglobin by immunoagglutination in myocardial infarction

The abnormally elevated quantity of myoglobin present in the plasma of 11 patients suffering of myocardial infarction was demonstrated by a rapid immunoagglutination slide-test. The results of this qualitative test were compared to the myoglobin concentrations measured by radioimmunology. Although the immunoagglutination test is less sensitive than the myoglobin assay, it proved to be very specific. Its rapidity of use, its reliability shown on 121 plasma specimens collected during the myocardial infarction evolution in the patients under study, will enable the clinician to use advantageously the very rapid myoglobinemia taking place in the first hours of infarction. Indeed, we have shown in agreement with the literature that the rise of myoglobin during the first hours of infarction occurs at a much earlier stage than does the increase of creatine kinase activity which was equally assayed during this work.     

Responses of bone turnover markers to repeated endurance running in humans under conditions of energy balance or energy restriction

Distance running in humans has been associated with both positive and negative effects on the balance of bone remodelling. There is evidence to suggest that the negative effects may be linked to a failure to balance energy expenditure with an adequate energy intake. Energy restriction is known to reduce the synthesis and serum concentration of insulin-like growth factor 1 (IGF-1), which plays an important role in bone formation. The purpose of the present study was to compare the effects of repeated periods of prolonged treadmill running, under conditions of either energy balance or energy restriction, on markers of bone turnover and serum IGF-1 concentration in trained distance runners. Eight male distance runners [mean age 25.1 (SD 5.9) years, maximal oxygen uptake 61.8 (SD 4.9) ml x kg(-1) x min(-1)] undertook an exercise and diet regime on two separate occasions, 2 weeks apart. On each occasion they performed an intensive, 60 min treadmill run on 3 consecutive days. On one occasion their energy intake was restricted to approximately 50% of their estimated energy requirement (RES), whereas on the other occasion they remained in energy balance (BAL). The N-terminal pro-peptide of type 1 collagen (P1NP), osteocalcin and IGF-1 were measured in serum collected between 0800 and 0900 hours, when fasted and rested, on the day before and the day after each regime. The cross-linked N-telopeptides of type 1 collagen and deoxypyridinoline were measured from 24 h urine collections made on the day before and the final day of each regime and adjusted for creatinine excretion. The results showed that the serum concentration of both P1NP and IGF-1 declined by 15% (P = 0.008) and 17% (P = 0.007) respectively in response to RES, but did not change in response to BAL (P > 0.05). A strong relationship was observed between the magnitude of the reduction in the serum concentration of P1NP and IGF-1 after RES (r = 0.97; P < 0.001). There were no changes in the other bone markers in response to either regime. The results suggested that in trained distance runners, repeated periods of prolonged running do not affect the balance of bone turnover unless energy balance is simultaneously altered. These findings support the link between a negative energy balance, a reduced synthesis or serum level of IGF-1 and reduced collagen synthesis. They may also help to explain the bone remodelling imbalance that has been observed in some male and female distance runners.     

Specificity of physiological adaptation to endurance training in distance runners and competitive walkers

Summary The present study was designed to evaluate the specificity of physiological adaptation to extra endurance training in five female competitive walkers and six female distance runners. The mean velocity ( ) during training, corresponding to 4 mM blood lactate [onset of blood lactate accumulation (OBLA)] during treadmill incremental exercise (training was 2.86 m·s^–1 SD 0.21 in walkers and 4.02 m·s^–1, SD 0.11 in runners) was added to their normal training programme and was performed for 20 min, 6 days a week for 8 weeks, and was called extra training. An additional six female distance runners performed only their normal training programme every day for about 120 min at an exercise intensity equivalent to their lactate threshold (LT) (i.e. a running of about 3.33 m·s^–1). After the extra training, there were statistically significant increases in blood lactate variables (i.e. oxygen uptake ( O₂) at LT, at LT, O₂ at OBLA, at OBLA; P<0.05), and running F for 3,000m (P<0.01) in the running training group. In the walking training group, there were significant increases in blood lactate variables (i.e., at LT, at OBLA; P<0.05), and walking economy. In contrast, there were no significant changes in lactate variables, running and economy in the group of runners which carried out only the normal training programme. It is suggested that the changes in blood lactate variables such as LT and OBLA played a role in improving F of both the distance runners and the competitive walkers. Furthermore, the significant improvement in walking economy brought about by extra endurance training might be a specific phenomenon for competitive walkers compared to runners.     

Serum myoglobin concentrations are decreased by beta-adrenergic stimulation

Summary During infusion with adrenaline in healthy subjects there was a more than 50% reduction in serum myoglobin concentrations. This effect appeared to be specific for beta-adrenergic stimulation, since no changes were seen after prior IV beta-blockade with propranolol, nor did noradrenaline affect the serum myoglobin levels.Oral beta-blockade with propranolol raised the basal serum levels of myoglobin and enhanced the exercise-related rise in serum myoglobin concentrations during ergometer cycling to exhaustion.These observations thus indicate that the beta-adrenergic system affects serum myoglobin concentrations. This should be kept in mind in the evaluation of myoglobin measurements for clinical purposes, and might reflect a physiologically relevant mechanism.     

Maximal aerobic power in primitive Indians

Summary Maximum oxygen consumption (V _O2max) and body fat measurement have been carried out on 32 Tarahumaras Indians who are used to daily long distance runs (runners) and on 30 subjects of the same ethnic group having sedentary habits (not runners). Extremely high values, 63 ml/kg · min, have been found in the runners group together with a low fat content of the body (11%): the non runners group displays a value ofV _O2max of 39 ml/kg · mm similar to other ethnic groups and an average body fat content of 18%.This work was supported by a grant from the Italian National Research Council (CNR), Section I.B.P.     

Bone status in elite male runners

The aim of our study was to compare long distance runners to body mass index (BMI)- and age-matched healthy controls with respect to bone parameters at all relevant loaded and nonloaded skeletal sites. Furthermore, we assessed the effect of running volume on bone parameters. Twenty elite male runners (21.1 km<1:15 h; volume >75 km/week/year) participated in the study (RG), 11 age- and BMI-matched male subjects (28±5 years) served as nontraining controls (CG). Subjects with any medication or illness affecting bone metabolism or with a family history of osteoporosis were not included. Bone parameters at various sites (total body, lumbar spine, femoral neck/hip, calcaneus) were measured by dual energy X-ray (DXA), quantitative computed tomography and quantitative ultrasound. Body composition was assessed via DXA and bioimpedance analysis; nutritional parameters were determined by 5-day dietary protocols. Training variables were assessed by questionnaires. Compared with nontraining controls runners had significantly higher BMD at all loaded sites (calcaneus, lower limbs, femoral neck, pelvis, and trabecular lumbar spine). BMD at nonloaded sites (ribs, upper limbs, and skull) was slightly but not significantly higher in the runners. We observed a low (r=0.30), nonsignificant association between training volume (km/week/year) and trabecular BMD of the femoral neck, which disappeared after adjusting for age, BMI, and body fat in this group of highly trained male runners. The effect of long distance running per se on bone parameters is not deleterious.