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PubMed2000

Comparison of exertional indices following moderate training in collegiate athletes.

BACKGROUND: To better understand the inflammatory response to two divergent training modalities: running and weight training. METHODS EXPERIMENTAL DESIGN: prospective, repeat measures, observational study of subjects over the course of 8-10 weeks of training. Data analysis was consonant with this design and included a repeat measures ANOVA with multiple posthoc comparisons. The level of significance was set at 0.05. SETTING: collegiate athletic training facilities. PATIENTS: twenty-two subjects comprised the study group. These included both male and female collegiate athletes, ages 17-22 years of age with a mean height of 178.6 cm, a mean weight of 77.5 kg and a mean lean body mass of 67.2 kg. Exclusion criteria consisted of hemophilia or chronic conditions requiring anti-inflammatory medication. INTERVENTIONS: training for runners (n=11) consisted of multiple 5-km runs throughout the course of a 60-75 minute workout. For a comparable time period, weight trainers participated in multiple joint, total body strengthening workouts. MEASURES: four exertional indices were examined. These included serum levels of creatine kinase, lactate, Interleukin-6, and C-reactive protein. Assessments of these markers were made immediately before and after each training session. Three sessions were monitored over an 8-10 week period. RESULTS: The data show that moderate exertion is accompanied by modest increases in these markers. Mean serum values did not exceed 125 U/L for serum creatine kinase, 5 mM/I for lactates, and 2.6 pg/ml for IL-6. C-reactive protein was sporadically detectable in weight lifters only. These increases were detected immediately postexercise. Each training modality produced a unique profile for creatine kinase and IL-6, suggestive of a training effect. CONCLUSIONS: Overall, the levels for all exertional markers reported herein are well below those reported for exhaustive exercise. As consistent exhaustive efforts can catalyze overtraining syndromes, periodic assessments of these exertional indices could help to document the appropriateness of the training stimulus.

Adolescent↗
PubMed2000

[Mucociliary clearance after aerobic exertion in athletes].

The Authors studied the modifications in nasal mucociliary clearance times before and after aerobic exertion in athletes. A total of 60 athletes with high-level training (age range 18-37 years) were selected for this study. Persons who smoked or had allergies, nasal sinus phlogosis or tumors, altered nasal cavity morphology (i.e. deviation of the septum and/or hypertrophy of the turbinates), fever or who were taking topic and/or systemic drugs or had previously undergone head and neck surgery were all ruled out of the study. The authors then studied the mucociliary clearance time (MCCT) in these subjects using the saccharin test. This test involves placing a small amount of saccharin on the medial face of the lower turbinate, approximately 1.5 cm from the anterior end and then evaluating the time that elapses before the patient perceives the sweet taste. This test was performed: in 30 subjects one hour prior to and 15 minutes after physical aerobic exertion; in the remaining subjects (controls) the test was performed twice with a 75 minute interval between them. The results showed that the mucociliary clearance time increased after exertion which was, on the average, 11.29 minutes. On the basis of these data, the Authors discuss the likely causes for the detected increase, and correlate it to changes in ventilation and nasal secretion viscosity during physical exercise. According to previous research, these variations are also found in untrained subjects who undergo physical exertion; for this reason, the Authors conclude that nasal clearance is not significantly affected by training.

Adult↗
PubMed2001

Chronic exertional compartment syndrome after minor injury to the lower extremity.

Since the 1950s, chronic exertional compartment syndrome of the lower leg has been thoroughly reported in the literature. The predisposing factors and pathophysiology of this condition, however, still are not fully understood. We present a case of a well-conditioned individual who developed a chronic exertional compartment syndrome of the left lower leg anterior compartment after a direct blow injury during a softball game. Trauma is not routinely implicated as a risk factor for chronic compartment syndrome, and the literature on this topic is scarce. We suggest that trauma, even low-velocity trauma, may precipitate a chronic exertional compartment syndrome. We review the literature regarding chronic exertional compartment syndromes preceded by trauma and offer explanations regarding the mechanisms by which a traumatic event may induce a chronic compartment syndrome.

Adult↗
PubMed2000

Effects of sympathetic inhibition on exertional dyspnoea, ventilatory and metabolic responses to exercise in normotensive humans.

Augmentation of circulating noradrenaline concentration stimulates ventilation during the initial stages of exercise and this is accompanied by an increased sensation of dyspnoea and exertion. This previous study [Clark, Galloway, MacFarlane, Henderson, Aitchison and McMurray (1997) Eur. Heart J. 18, 1829-1833] suggested a link between dyspnoea, which commonly limits exercise tolerance in heart failure patients, and high circulating noradrenaline concentration in these patients. The present study investigated this relationship further using sympathetic inhibition. Ten healthy normotensive males performed 10 min of submaximal cycling exercise at approx. 70% of maximal oxygen uptake per min (VO2max) on three occasions one week apart. The first of these sessions was a familiarization session and the other two were experimental study days. On each of the study days, subjects attended the laboratory in the morning after an overnight fast and, following a resting blood sample, were administered placebo or moxonidine (0.4 mg) in a double blind cross-over design. After a 90-min absorption period, subjects undertook the exercise task. Blood was drawn, expired gas was analysed breath by breath, blood pressure, heart rate and ratings of perceived dyspnoea and exertion were obtained. Moxonidine treatment significantly reduced plasma noradrenaline concentration (P < 0.01), mean arterial pressure (P < 0.01), and blood glycerol concentration (P < 0.05), but no differences were observed in heart rate, the ventilatory response to exercise or subjective ratings of dyspnoea and exertion. This study indicates that reducing sympathetic activity does not affect ventilation, perceived dyspnoea or perceived exertion in normotensive males. Therefore it can be concluded that reducing sympathetic activity may not be an appropriate strategy to help reduce perceived dyspnoea.

Adult↗
PubMed1994

Acute exertional compartment syndrome occurring after performance of the army physical fitness test.

Acute exertional compartment syndrome has been described as occurring after sustained maximal exertion. The case described is that of acute exertional compartment syndrome of the leg occurring in a soldier after he attempted to complete the Army physical fitness test. This condition was initially neglected; necrotic muscle and acute tubular necrosis were sequelae. Earlier intervention could have occurred if the signs and symptoms were considered by the treating health care professionals. All active duty troops are required to perform to maximum exertion. Their complaints should be considered with the same differential diagnosis as those of a highly trained athlete.

Acute Disease↗
PubMed1996

Detecting submaximal grip exertions of variable effort by electromyography.

The purpose was to determine if the surface electromyogram (EMG) would allow detection of submaximal grip exertions of variable effort. Fifteen healthy subjects were instructed on different trials to give maximal 100% efforts, fixed 50% submaximal efforts, or submaximal efforts of variable amount (30, 40, 50 or 70%) with the right hand. The subjects were tested at each of the five handle positions of the Jamar dynamometer. Surface EMG was obtained for the right palmaris longus/flexor carpi radialis muscles. Consistent with previous research was the finding that the variable effort condition yielded a bell-shaped force curve, similar to that produced by patients with true injuries. The key finding was that 100% and 50% exertions yielded linear EMG amplitude curves whereas the variable-effort exertion yielded a bell-shaped or quadratic curve. Thus, the EMG did allow for detection of the variable submaximal effort. However, the 100% and 50% exertions could not be distinguished by the average sustained force/peak force ratio. The EMG has the potential of being a valuable adjunct for the clinician needing to determine if a patient is feigning loss of grip strength.

Adult↗
PubMed1996

Association of conventional and exertional coronary heart disease risk factors in 5,000 apparently healthy men.

BACKGROUND AND HYPOTHESIS: The aim of this study was to define the prevalence of previously undetected coronary heart disease among asymptomatic males, aged 30-65 years, by means of resting and exercise electrocardiography in conjunction with an analysis of conventional and exertional coronary risk factors. METHODS: Between January 1985 and December 1989 we examined 5,000 clinically asymptomatic subjects. A detailed case history was obtained for each individual, followed by a complete physical examination, comprehensive blood (including lipid) profile, lung function tests, chest x-ray, a resting 12-lead electrocardiogram (ECG), and a maximal treadmill exercise ECG. Whenever possible, on-line computerized respiratory analysis (Beckman Metabolic Measurement Cart) was carried out during the exercise tests. Conventional and exertional coronary heart disease risk factors were also recorded. RESULTS: A total of 162 persons (3.2%) showed abnormal S-T segment responses during the exercise or recovery period. Of these, 92 subjects underwent further investigations: coronary angiography (79), 201thallium scanning (13), 201thallium scanning followed by coronary angiography (7). Of the 86 patients who proceeded to coronary angiography, 19 (22%) had either normal coronary artery anatomy or only insignificant disease. Among the 67 (78%) of patients with significant angiographically demonstrable disease, 26 received coronary artery bypass grafting, 7 underwent coronary angioplasty, and the remainder continued on medical management. CONCLUSIONS: These results are discussed in relation to a variety of conventional and exertional coronary risk factors.

Adult↗
PubMed1995

Hemiatrophy, juvenile-onset exertional alternating leg paresis, hypotonia, and hemidystonia and adult-onset hemiparkinsonism: the spectrum of hemiparkinsonism-hemiatrophy syndrome.

A 45-year-old woman with a history of probable perinatal craniocerebral trauma resulting in mild asymptomatic right hemiatrophy developed right leg weakness and hypotonia alternating with dystonia only after prolonged exertion at age 12. At age 27, she developed right-sided parkinsonism. Exertional paresis and dystonia and parkinsonism responded completely to levodopa; however, she developed a progressive reduction in the duration of action of levodopa over the first 4 years of treatment. Investigations including computed tomography, magnetic resonance imaging, [18F]fluorodopa, and [18F]fluorodeoxyglucose positron emission tomography scans suggested a static lesion involving the left substantia nigra. This unusual exertion-induced weakness and hypotonia alternating with hypertonia and dystonia has not been reported previously. The role of dopamine deficiency in dystonia and the role of levodopa in the development of fluctuations in Parkinson's disease are discussed. Review of the literature, including this patient, emphasizes the heterogeneity of the syndrome of hemiparkinsonism-hemiatrophy.

Antiparkinson Agents↗
PubMed1987

Perceived exertion related to heart rate and blood lactate during arm and leg exercise.

To compare some psychophysiological responses to arm exercise with those to leg exercise, an experiment was carried out on electronically braked bicycle ergometers, one being adapted for arm exercise. Eight healthy males took part in the experiment with stepwise increases in exercise intensity every 4 min: 40-70-100-150-200 W in cycling and 20-35-50-70-100 W in arm cranking. Towards the end of each 4 min period, ratings of perceived exertion were obtained on the RPE scale and on a new category ratio (CR) scale:heart rate (HR) and blood lactate accumulation (BL) were also measured. The responses obtained were about twice as high or more for arm cranking than for cycling. The biggest difference was found for BL and the smallest for HR and RPE. The incremental functions were similar in both activities, with approximately linear increases in HR and RPE and positively accelerating functions for CR (exponents about 1.9) and BL (exponents 2.5 and 3.3 respectively). When perceived exertion (according to the CR scale) was set as the dependent variable and a simple combination of HR and BL was used as the independent variable, a linear relationship was obtained for both kinds of exercise, as has previously been found in cycling, running, and walking. The results thus give support for the following generalization: For exercise of a steady state type with increasing loads the incremental curve for perceived exertion can be predicted from a simple combination of HR and BL.

Adult↗
PubMed1989

Effects of pre-motion electromyographic silent period on dynamic force exertion during a rapid ballistic movement in man.

The effects of pre-motion silent period (PSP) on dynamic force exertion were studied in ten healthy subjects performing ballistic elbow extensions. The experiments were designed to evaluate the significance of mean differences between the averaged dynamic force curves of two groups: PSP-presence groups and PSP-absence groups. The presence of PSP was judged quantitatively and automatically by means of a newly developed method using statistical analysis. The results indicated that there were two effects of PSP on dynamic force exertion: one was a reducing effect, observed prior to the movement; the other was a reinforcing effect, observed in the first part of the ballistic movement. The duration of the reinforcement was significantly correlated with the duration of the reducing effect of PSP. The findings suggested that the reinforcement of dynamic force may be produced by the pre-stretch of agonistic muscles caused by prior force reduction due to PSP occurrence. The fact that PSP plays an important role in dynamic force exertion suggests that PSP may be incorporated in the central motor control system designed to interrupt the background activity, to stretch the agonist and to reinforce the dynamic force.

Adult↗
PubMed1990

Effect of alcohol on perceived exertion in relation to heart rate and blood lactate.

The purpose of the study was to determine whether the perception of exertion is affected by alcohol during physical performance and whether altered self-rating of exertion is the result of an altered perception per se or of an altered physical capacity to perform work. Ten healthy men participated. Each subject was his own control and received an alcohol dose corresponding to 1 g.kg-1 body mass in 40% solution in the experimental session. The exercise test was performed on a cycle ergometer with an initial intensity of 50 W which was increased stepwise by 50 W at 4-min intervals up to near-maximal. The rating of perceived exertion (RPE) did not differ between alcohol and control sessions. Alcohol induced a significant increase in heart rate during exercise at 50 W (delta x = 8 beats.min-1) and at 100 W (delta x = 10 beats.min-1), while the change at higher intensities was insignificant. The systolic blood pressure and the blood lactate concentration were not significantly changed by alcohol. It is concluded that a moderate dose of alcohol does not alter RPE during physical exercise either per se or secondarily to an altered physical capacity to perform work.

Adult↗
PubMed1984

Differential ratings of perceived exertion and various physiological responses during prolonged upper and lower body exercise.

This study examined whether prolonged exercise employing upper or lower body muscle groups led to significant alterations in three differentiated ratings of perceived exertion (RPE). Multiple regression analyses were used to identify those physiological responses which accounted for the greatest variability in these three RPE. Nine volunteer males performed 60 min of arm crank and cycle exercise at similar absolute and at similar relative exercise intensities. There were no significant differences (P greater than 0.05) between arm and leg exercise for oxygen uptake (VO2) during the absolute tests (approximately 1.60 1 . min-1) or during the relative tests (approximately 60% peak VO2). The RPE included local RPE (muscle and joint exertion), central RPE (ventilatory and circulatory exertion), and overall RPE. During the absolute tests, the final means for all three RPE were lower (P less than 0.05) for leg than arm exercise. No differences (P greater than 0.05) were found during the relative tests between arm and leg exercise for any of the three RPE. Local RPE was generally higher than central RPE. The various physiological responses accounted for more (total) variance in all three RPE for arm than leg exercise (absolute and relative arm exercise: median R2 = 0.99; absolute and relative leg exercise: median R2 = 0.75). Lactate and the ventilatory equivalent of oxygen made the greatest contribution to R2. These data suggest that RPE may be more closely related to relative exercise intensity, and perceptual cues may be more readily monitored from smaller muscle masses such as the upper body. Further, steady-state RPE was not attained during prolonged upper body exercise.

Adult↗
PubMed1985

The increase of perceived exertion, aches and pain in the legs, heart rate and blood lactate during exercise on a bicycle ergometer.

This study was designed to show the general increase in perceived exertion, perception of aches or pain in the legs, heart rate (HR), and blood lactate, and the covariance between these variables during bicycle ergometer work, and to describe individual differences both within and between power levels by testing a large group (28 male students). Estimates of perceived exertion and feelings of aches or pain in the legs were recorded using Borg's category-ratio scale (CR-10). The subjects were tested with a stepwise increase of power levels with 40 W increments up to a voluntary maximum. Though HR increases fairly linearly with power, the other variables follow positively accelerating functions with exponents of about 1.6-2 for the perceptual variables, and an exponent of about 3 for blood lactate. The results from the 8 most fit subjects could be described in the same way as for the whole group except for blood lactate, where there was a need to include a threshold value (b), that, together with a rest value (a), shows the starting point of the function (R = a + c(W - Wo)n). The data support the idea that a combination of heart rate and blood lactate is a better predictor of perceived exertion and feelings of aches and pain in the legs, than is each of the single physiological variables taken alone.

Adult↗
PubMed2003

Regulating intensity using perceived exertion during extended exercise periods.

The present study was undertaken to examine the validity of using the OMNI scale of perceived exertion to regulate intensity during extended exercise periods. Forty-eight subjects (24 male, 24 female) were recruited and each subject completed a maximal graded exercise test (GXT) and two 20-min submaximal exercises. During the GXT, ratings of perceived exertion (RPE) as well as oxygen uptake (VO(2)) and heart rate (HR) equivalent to 50 and 70% of maximum VO(2) (VO(2max)) were estimated. During each submaximal exercise, subjects were instructed to produce and maintain a workload equivalent to the RPE estimated at 50 or 70% VO(2max), and VO(2) and HR were measured every 5 min throughout the exercise. Of the 48 subjects, 12 (6 male and 6 female) performed both the estimation and production trials on a treadmill (TM/TM), 12 (6 male and 6 female) performed both the estimation and production trials on a cycle ergometer (C/C), 12 (6 male and 6 female) performed the estimation trial on a treadmill and the production trial on a cycle ergometer (TM/C), and 12 (6 male and 6 female) performed the estimation trial on a cycle ergometer and the production trial on a treadmill (C/TM). No differences in VO(2) between the estimation and any 5 min of the production trial were observed at either intensity in TM/TM and C/C. No differences in HR between the estimation and any 5 min of the production trial were also observed at 50% VO(2max) in TM/TM and at both 50 and 70% VO(2max) in C/C. However, HR was higher at 20th min of the production trial at 70% VO(2max) in TM/TM. Both the VO(2) and HR were generally lower in TM/C and higher in C/TM. However, these differences diminished when values were normalized using VO(2max) of the same mode that other groups had attained. These data suggest that under both intra- and intermodal conditions, using the OMNI perceived exertion scale is effective not only in establishing the target intensity at the onset of exercise, but also in maintaining the intensity throughout a 20-min exercise session.

Adaptation, Physiological↗
PubMed2004

The effects of different inspiratory muscle training intensities on exercising heart rate and perceived exertion.

This study investigated the relationship between the intensity of an inspiratory muscle training programme and its effect on respiratory muscle strength, exercising heart rate, and ratings of perceived exertion. A total of 66 subjects were randomly assigned to one of three groups. One group trained at 100% of maximum inspiratory pressure (MIP) for 6 weeks (MAX, n=22). A second group performed 6 weeks of inspiratory muscle training at 80% of MIP (SUB, n=21) and a third control group received no inspiratory training (CON, n=23). Both the MAX and SUB training groups improved MIP relative to the control group [32 (19) cmH(2)O, P=0.01; 37 (25) cmH(2)O, P=0.001, respectively]. A significant decrease in heart rate [-6 (9) beats min(-1), P=0.02] and rating of perceived exertion [-0.5 (1.4), P=0.04] was observed for the MAX group only. It is concluded that 6 weeks of both MAX and SUB training were sufficient to improve inspiratory muscle strength. However, exercising heart rate and perceived exertion decreased with MAX training only.

Adaptation, Physiological↗
PubMed1984

Influence of nutritional status on exertion-induced forearm amino acid metabolism in normal man.

Normal volunteers were evaluated in the postabsorptive state, following 10 days of protein-calorie starvation, and during intravenous feeding ( ivf ) to determine the impact of nutritional status upon exertion-induced muscle amino acid metabolism. An isolated forearm model allowed an evaluation of recovery of metabolism following 1 min of submaximal isotonic exercise. Forearm blood flow returned to near basal levels within 15 min after exertion during postabsorptive and ivf conditions, but remained greater than or equal to 150% of basal at 1 hr after exercise during starvation. At 30 and 60 min after exercise, forearm plasma flux of total and essential amino acids were unchanged from basal in the postabsorptive state. However, the pattern of essential amino acid flux demonstrated a relative reduction in isoleucine and leucine efflux compared with basal, and this pattern persisted throughout 1 hr of recovery. During starvation, a significant (P less than 0.05) increase in total and essential amino acid efflux was observed throughout the recovery period. Starvation was also associated with significant increases in alanine and lysine efflux during recovery. Intravenous feeding was associated with a significant (P less than 0.05) uptake of essential amino acids with respect to basal levels at 30 min after exercise. At 60 min, there was a shift to total amino acid efflux but no change from basal flux for essential amino acids. During ivf , the pattern of essential amino acid uptake returned to basal within 1 hr after exertion.

Adult↗
PubMed1989

Effect of exertion on the stimulation of ornithine decarboxylase activity by growth hormone in rats.

To investigate the effect of stressful stimulation on tissue responsiveness to growth hormone (GH), we examined ODC activity as a measure of hepatic sensitivity to the hormone during forced exertion in rats. GH caused a 15-fold increase in ODC activity in the livers of resting rats at 3 hours after the injection of hormone. Forced walking in a rotating cylinder enhanced the effect of GH on ODC activity by up to 66% above the effect in resting rats, and this enhancement was positively related to the speed of rotation of the cylinder. These results suggest that tissue hypersensitivity to GH stimulation is a consequence of forced exertion. This hypersensitivity to GH would tend to compensate for the inhibitory effects of forced exertion on GH secretion in rats.

Animals↗
PubMed1994

Effect of phenylbutazone on the haemodynamic, acid-base and eicosanoid responses of horses to sustained submaximal exertion.

The systemic haemodynamic and acid-base effects of the administration of phenylbutazone (4.4 mg kg-1 intravenously) to standing and running horses were investigated. Phenylbutazone, or a placebo, was administered to each of six mares either 15 minutes before, or after 30 minutes of a 60-minute submaximal exercise test which elicited heart rates approximately 55 per cent of maximal, and to the same horses at rest. The variables examined included the cardiac output, heart rate, systemic and pulmonary arterial pressures, right atrial and right ventricular pressures, and arterial and mixed venous blood gases and pH. Serum sodium, potassium and chloride concentrations, and plasma thromboxane B2, 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), and prostaglandin E2 (PGE2) concentrations were measured in separate studies using similar protocols in the same horses. Running produced increases in heart rate, cardiac output, mean arterial and right ventricular pressure, and decreases in total peripheral resistance. The acid:base responses to exertion were characterised by respiratory alkalosis. Exertion did not significantly influence plasma 6-keto-PGF1 alpha or PGE2 concentrations but plasma thromboxane B2 concentrations were increased significantly by 60 minutes of exertion in the untreated horses. This exercise-induced increase in plasma thromboxane B2 concentration was inhibited by the previous administration of phenylbutazone, but phenylbutazone did not produce detectable changes in systemic haemodynamic or acid-base variables in either standing or running horses.

6-Ketoprostaglandin F1 alpha↗