Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “EXERTION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24Linked to original sources
PubMed1977

Perceived exertion of absolute work during a military physical training program.

The purpose of this study was to compare the rating of perceived exertion (PRE) and heart rate (HR) in two groups of 60 military personnel who differed in their level of fitness as determined by maximal oxygen uptake (VO2 max). At an initial testing period (T1), Group I represented a sample of personnel not participating in a training program while Group II had engaged in an endurance program (2--4 mile run/day) for 5 months. Six months later (T2), Groups I and II were retested after having participated in the program for 6 and 11 months, respectively. RPE and HR were measured at the end of each min of a 6 min run at an absolute workload of 6 mph, 0% grade on the treadmill. At T1, Group II had a significantly lower HR at each min of work but no difference existed in RPE between groups at any time during the run. At T2, both groups showed a significant decrease in HR and RPE during each min when compared lobgitudinally. The data suggest that the perception of the intensity of absolute work does not differ in groups differing in their level of fitness when studied cross-sectionally. However, significant reductions in perceived exertion occur following physical training.

Adult↗
PubMed1986

A comparison of response and production protocols for assessing perceived exertion.

Two cycle ergometer protocols for assessing perceived exertion were compared before and after a fatiguing run. In the response (R) protocol, the subject rated the perceived exertion (RPE) of a series of power outputs assigned by the investigator. In the production (P) protocol, the investigator selected the RPE values and the subject adjusted his power output using a hand-held control. The relationship between RPE and power output (the regression coefficient and the slope and intercept of the regression line) was the same for both protocols. Fatigue due to the run caused a small increase in RPE (average 1.5 units) at a given exercise intensity and a commensurate decrease in power output (average 19 W) for a given RPE. The P protocol is safer than the R protocol because it makes no assumptions with regard to the physical condition of the subject. It is superior to the R protocol because it is an interval scale. These advantages suggest that the P protocol should be used instead of, or at least in addition to, the more traditional R protocol.

Adult↗
PubMed1988

Food deprivation decreases the exertion-induced acid hydrolase response in mouse skeletal muscle.

Strenuous prolonged running causes muscle fibre necrosis in skeletal muscles. The muscle injury is associated with inflammation and a strong increase in the total activities of certain acid hydrolases a few days after exertion. The activity changes of acid hydrolases quantitatively well reflect the severity of histopathological changes during the myopathy (for review see Salminen, Acta Physiol Scand [Suppl 539] 1985). In this study male NMRI-mice were exposed to a protocol of fasting and refeeding together with or without a 6 h run on a treadmill at 13.5 m.min-1. The animals were killed 4 days after the exercise and samples from the red part of quadriceps femoris were analyzed for arylsulfatase (ASase) and beta-glucuronidase (GUase) activities. Starvation protocols did not affect ASase or GUase. Running caused a 3.2-fold increase in ASase and a 5.1-fold increase in GUase. If mice were exercised in the fasted condition a normal exercise response occurred in both activities, but when mice were exercised 2 days after the finish of fasting the exercise response was greatly diminished. Thus food deprivation followed by 2 days refeeding induces a protection against exercise myopathy in mice. The protection greatly resembles that induced by regular endurance training preceding strenuous prolonged exertion.

Animals↗
PubMed1995

Effects of beraprost sodium, a new prostaglandin I2 analog, on parameters of hemostasis, fibrinolysis, and myocardial ischemia in patients with exertional angina.

The purpose of this study was to investigate the effects of beraprost sodium, a stable prostacyclin analog, on the parameters of hemostasis, fibrinolysis, and myocardial ischemia in patients with exertional angina. Thirty-one patients with exertional angina who had significant organic coronary artery stenosis in at least one of the three major coronary arteries were selected. All patients underwent quantitative exercise thallium-201 emission computed tomography before and 1 month after 120 micrograms per day of beraprost sodium administration. Before exercise, blood samples were collected from 8:30 a.m. to 9:30 a.m. after the patients had been lying in bed undisturbed for at least 10 minutes. Plasma platelet factor 4 (PF4), fibrinopeptide A (FPA), tissue plasminogen activator antigen (t-PA), and plasminogen activator inhibitor-1 activity (PAI-1) were measured. There were no significant differences in exercise parameters on both exercise tests. However, both the extent and severity scores of ischemia were significantly aggravated (p < 0.05 for both) during beraprost sodium administration. Plasma FPA levels decreased significantly during beraprost sodium administration (p < 0.01). Likewise, plasma PF4 levels decreased significantly during beraprost sodium administration (p < 0.05). As for plasma t-PA antigen levels, there was no significant difference before versus during beraprost sodium administration. Plasma PAI-1 activity levels decreased significantly during beraprost sodium administration (p < 0.05). The results indicate that beraprost sodium has strong antithrombogenic properties. However, its aggravation of myocardial ischemia may limit clinical usage.

Angina Pectoris↗
PubMed1996

Work and power outputs determined from pedalling and flywheel friction forces during brief maximal exertion on a cycle ergometer.

Work and power outputs during short-term, maximal exertion on a friction loaded cycle ergometer are usually calculated from the friction force applied to the flywheel. The inertia of the flywheel is sometimes taken into consideration, but the effects of internal resistances and other factors have been ignored. The purpose of this study was to estimate their effects by comparing work or power output determined from the force exerted on the pedals (pedalling force) with work or power output determined from the friction force and the moment of inertia of the rotational parts. A group of 22 male college students accelerated a cycle ergometer as rapidly as possible for 3 s. The total work output determined from the pedalling force (TWp) was significantly greater than that calculated from the friction force and the moment of inertia (TWf). Power output determined from the pedalling force during each pedal stroke (SPp) was also significantly greater than that calculated from the friction force and the moment of inertia. Percentage difference (% diff), defined by % diff = ¿(TWp - TWf)/TWf¿ x 100, ranged from 16.8% to 49.3% with a mean value of 30.8 (SD 9.1)%. It was observed that % diff values were higher in subjects with greater TWp or greater maximal SPp. These results would indicate that internal resistances and other factors, such as the deformation of the chain and the vibrations of the entire system, may have significant effects on the measurements of work and power outputs. The effects appear to depend on the magnitudes of pedalling force and pedal velocity.

Adult↗
PubMed1995

Age-response effectiveness of gallopamil for the treatment of myocardial exertional ischemia. A medium-term randomized cross-over double-blind placebo-controlled trial.

We evaluated the efficacy and safety of gallopamil 150 mg daily in middle-aged and elderly patients with stable exertional ischemia, using a medium-term randomized double-blind cross-over placebo-controlled trial. Twenty middle-aged patients (52.8 +/- 6 years; range 38-61 years) and 14 elderly patients (67.4 +/- 2.8 years; range 65-73 years) with stable exertional ischemia underwent a bicycle exercise test. After a run-in period, both groups received treatment with either placebo or gallopamil 50 mg tid for 28 days. At the end of this time, each patient crossed over to the alternate regimen. Gallopamil significantly reduced heart rate, blood pressure and rate pressure product (from 15.37 +/- 2.7 to 13.65 +/- 4.16 U x 10(-3); p < 0.01) in elderly patients at submaximal exercise, but had no effect in middle-aged patients (from 14.52 +/- 4.45 to 13.49 +/- 3.77 U x 10(-3); p = NS). At peak exercise, none of the hemodynamic parameters was modified with gallopamil in either group. At peak exercise, both middle-aged and elderly patients achieved rate-pressure products similar to those reached during placebo at higher work loads. Exercise duration and maximal work load significantly increased in both groups. Electrocardiographic signs of ischemia were favorably influenced by gallopamil in both groups (from 1.39 +/- 0.5 mm to 0.76 +/- 0.73 mm; p < 0.001 in the middle-aged patients and from 1.5 +/- 0.34 mm to 1 +/- 0.76 mm; p < 0.01 in the elderly patients).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2002

Can increased intra-abdominal pressure in humans be decoupled from trunk muscle co-contraction during steady state isometric exertions?

The purpose of the present study was to investigate whether increased intra-abdominal pressure (IAP) can be achieved without elevating the overall trunk muscle co-contraction that causes increased spine compression force. Ten subjects performed isometric trunk flexion, extension, and lateral bending exertions while generating 0%, 40% and 80% of their maximal IAP or while co-contracting trunk muscles without consciously raising IAP. An additional three subjects performed a variety of ramp IAP, co-contraction and isometric exertion tasks while holding their breaths and while exhaling. An 18 degree-of-freedom, electromyogram (EMG)-assisted biomechanical model was used to quantify trunk muscle co-contraction with calculations of spine compression force and stability. Spine stability and compression force increased proportionally with increased IAP regardless of whether the subjects intentionally generated IAP or consciously avoided it. This increase was accomplished with significantly greater co-contraction of 12 major trunk muscles. The EMG activation of all muscles was highly correlated with IAP and intra-thoracic pressure (ITP) ( r from 0.59 to 0.95). Activity of the thoracic erector spinae correlated the best with ITP ( r=0.81), which in turn was correlated with IAP ( r=0.91). It was not possible to co-contract trunk muscles without generating IAP and ITP, or conversely to generate IAP without trunk muscle co-contraction and increased ITP.

Abdominal Cavity↗
PubMed2003

Overall and differentiated ratings of perceived exertion at the respiratory compensation threshold: effects of gender and mode.

Research on gender differences in ratings of perceived exertion (RPE) has been equivocal with few studies comparing exercise modes and differentiated RPE. The current study examined gender differences in overall and differentiated RPE at the respiratory compensation threshold (RCT) during cycling and treadmill exercise. Each minute during a maximal treadmill and maximal cycling test, men (n=18) and women (n=16) estimated RPE corresponding to overall (RPE-O), legs (RPE-L), and breathing/chest (RPE-C) exertion. A 2 (gender) x 2 (mode) x 3 (RPE-O, RPE-L, RPE-C) repeated measures MANOVA revealed no significant mode x gender or RPE x gender interactions. The exercise mode x RPE interaction approached significance (P=0.055) when cycling [mean (SD) 14.8 (2.9)] and treadmill exercise [12.8 (2.9)] were compared. No main effects for gender [men: 13.7 (2.6), women: 13.4 (2.6)] were detected. Main effects for mode showed RPE to be significantly greater during cycling [14.4 (2.8)] versus treadmill exercise [12.7 (2.9)]. Main effects for differentiated RPE showed RPE-L [13.8 (2.6)] to be significantly greater than RPE-O [13.5 (2.6)] and RPE-C [13.3 (2.6)]. Results suggest that overall and differentiated RPE at the RCT are not significantly different between genders during cycling or treadmill exercise. While RPE-L was statistically greater than RPE-O and RPE-C, the magnitude of the differences makes this result of little practical significance. The marginal interaction suggests greater RPE-L values might be expected at the RCT during cycling versus treadmill exercise. However, results suggest that minimal RPE differences exist between men and women during cycling and treadmill exercise.

Adaptation, Physiological↗
PubMed1998

Differentiated ratings of perceived exertion at ventilatory threshold in children and adults.

The purpose of this study was to examine overall, leg and chest ratings of perceived exertion (RPE) at ventilatory threshold (Thvent) in 16 children (mean age 10.9 years) and 17 adults (mean age 24.3 years). Thvent and maximum oxygen consumption (VO2max) were measured during a graded exercise test on a cycle ergometer. Overall, leg and chest RPE were obtained at the end of each exercise stage. VO2max was 49.9 (8.5) and 47.1 (6.1) ml x kg(-1) x min(-1) [mean (SD)] in the adults and children, respectively (P > 0.05). Relative to VO2max, Thvent was 61.7 (5.3)% in the adults and 64.7 (5.2)% in the children (P > 0.05). Overall, leg, and chest RPE values at Thvent for the adults were 11.5 (2.6), 11.9 (2.5), and 10.5 (2.5), while for the children these values were 13.6 (2.2), 14.1 (2.2), and 12.6 (2.3), respectively. All RPE values were higher for the children (P < 0.05). These results suggest that children are able to discriminate levels of exertion in different parts of their body during graded exercise. Furthermore, children rate an intensity corresponding to Thvent to require a greater overall, leg and chest effort than adults exercising at a similar intensity. This indicates that children experience more pronounced cardiorespiratory and muscular sensations during this type of exercise.

Adult↗
PubMed2001

Symptoms and therapies: exertional and sexual headaches.

This article discusses the headache disorders associated with physical and sexual activity, highlighting their differences and similarities. The place of exertional and sexual headaches in the classification of the International Headache Society and in the proposed classification of Indomethacin-Responsive Headache Disorders is addressed here. The Valsalva's maneuver as a shared pathophysiologic mechanism is mentioned as well. Exertional headaches are divided into two subtypes, according to the pattern of physical exercises. Sexual headaches are divided into three subtypes, based on the onset time, related to orgasm. The clinical characteristics of each type are presented, and their etiologies pointed out. The diagnostic approach is discussed, as well as the nonpharmacologic and pharmacologic treatment options.

Coitus↗
PubMed1982

Verapamil therapy for stable exertional angina pectoris.

Clinical and exercise responses to therapy with the calcium-channel blocking agent verapamil were assessed in 26 patients with stable exertional angina pectoris using a double-blind, placebo-controlled, randomized crossover study design. Verapamil, 480 mg daily, reduced the frequency of angina attacks (5.6 +/- 7.3 to 2.2 +/- 3.0 attacks per week, p less than 0.001) and number of nitroglycerin tablets consumed (3.4 +/- 4.9 to 1.2 +/- 2.5 tablets per week, p less than 0.05), and increased exercise duration (6.4 +/- 2.1 to 7.5 to 1.8 minutes, p less than 0.001) (all data are mean +/- standard deviation). These changes were significantly better than those seen with placebo. These beneficial effects of verapamil were related to significant reduction in the heart rate-systolic blood pressure product during submaximal exercise. Adverse effects from verapamil were few and consisted primarily of constipation in 6 patients. A total of 193 patients had been entered in 6 independent clinical trials, which have compared verapamil with placebo for the treatment of stable exertional angina pectoris, using a similar study design. The combined evidence from all these studies indicates that verapamil is a highly effective and safe drug for the treatment of stable effort-related angina pectoris.

Adult↗
PubMed1977

Exertion-induced rhabdomyolysis with acute renal failure and disseminated intravascular coagulation in sickle cell trait.

From 1970 to 1974, among thousands of trainees seen at two large military installations who were subjected to the same physical and environmental stresses, only four recruits were hospitalized because of acute exertional rhabdomyolysis, renal failure and coagulopathy. The illness followed the performance of vigorous exercise. These four patients had sickle cell trait. In an attempt to explain this association, the data in these four cases are summarized. The hypothesis is then developed that rhabdomyolysis and endothelial damage, terminating in severe coagulopathy, may more likely occur in patients with sickle cell trait who are subjected to virorous physical exertion.

Acute Kidney Injury↗
PubMed1988

Lactate dehydrogenase M-subunit deficiency: a new type of hereditary exertional myopathy.

Three families with a complete deficiency of the lactate dehydrogenase M subunit show exertional myoglobinuria. The response to ischemic forearm work is characteristic in these three families: an increase of venous lactate concentration after ischemic work was not observed and a marked increase of venous pyruvate was found. Glycolysis was markedly retarded in the patient's muscle in the glyceraldehyde 3-phosphate dehydrogenase (GA3PD) step. A significant increases in glyceraldehyde 3-phosphate, dihydroxyacetone phosphate and fructose 1,6-diphosphate were observed. The glycolysis retardation may be attributed to the impaired reoxidation of NADH produced by GA3PD action. The cytosolic fraction of skeletal muscle is rich in alpha-glycerophosphate dehydrogenase. This enzyme reoxidizes the excess NADH and drains triose phosphates from the glycolytic pathway under anaerobic conditions. For this reason, ATP production was significantly impaired and muscle cells were damaged in these patients. Consequently, the cytosolic enzymes and proteins such as creatine kinase and myoglobin were released into the blood stream. Otherwise, patients with a lactate dehydrogenase M-subunit deficiency do not show muscle stiffness and myoglobinuria under ordinary circumstances. They complain of muscle rigidity and sudden myoglobinuria after strenous exercise under anaerobic conditions. Thus, the lactate dehydrogenase M-subunit deficiency does not show any symptoms under ordinary circumstances, but is a latent hereditary disorder, now recognized as a new type of hereditary exertional myoglobinuria.

Adolescent↗
PubMed1995

Comparison of efficacy of nisoldipine, metoprolol, and isosorbide dinitrate in patients with stable exertional angina: a randomized, cross-over, placebo-controlled study.

We evaluated the acute antianginal effect of oral nisoldipine (10 mg), metoprolol (40 mg), and long-acting isosorbide dinitrate (20 mg) in 15 patients with stable exertional angina. The patients performed symptom-limited treadmill exercise at 2 h after the administration of placebo (Placebo stages 1 and 2) and each of the active drugs. After Placebo stage 1, the patients were randomized for cross-over evaluation of the acute effect of a single oral dose of placebo (Placebo stage 2), nisoldipine, metoprolol, or long-acting isosorbide dinitrate. All 15 patients developed angina during all of exercise tests and their exercise tests were terminated at the onset of angina. The time until development of 0.1 mV ST segment depression was increased by all three drugs compared to placebo, and it was significantly longer with metoprolol than with isosorbide dinitrate. Similarly, the time to ceasing exercise because of angina was also prolonged by all three drugs. The exercise time was longer with nisoldipine and metoprolol compared to isosorbide dinitrate, but there was no significant difference between nisoldipine and metoprolol. In conclusion, metoprolol and nisoldipine more effectively prolonged exercise compared to long-acting isosorbide dinitrate in patients with stable exertional angina.

Administration, Oral↗
PubMed2005

Effect of a splint on measures of sustained grip exertion under different forearm and wrist postures.

Despite the facts that gripping tasks have been found to be highly correlated with CTS and that splints are gaining popularity as personal protective equipment, the influence of splints on grip performance has not been determined adequately. The present study intends to investigate the influence of splints without the volar parts as well as of forearm and wrist postures on grip performances including maximal volitional contraction (MVC), maximum acceptable sustained time (MAST), cumulated exertion output (CEO), and normalized exertion level (NEL). Twenty college-student volunteers, 10 males and 10 females, were recruited. The factors of interest were gender, forearm position, wrist deviation, and splint (with and without). The forearm positions were set at 30 degrees internal shoulder rotation, 0 degrees internal shoulder rotation, and 30 degrees external shoulder rotation, the angles being measured between the sagittal plane and the long axis of dominant forearm. The wrist deviations were extension 30 degrees , neutral, and flexion 30 degrees , the angles being measured between the sagittal plane and the long axis of the grip gauge. The results indicate that the gender effect is the most dominantly significant on all evaluated response variables. Males have more MVC (220 vs. 337N), longer MAST (20.2 vs. 10.5s), and greater CEO (4306 vs. 1638Ns), but less NEL (66.6 vs. 73.9%MVC). The forearm posture is shown to be significant only on MVC. In addition, the effect of wrist posture cannot shift all responses, nor can the effect of splints. In general, a splint without volar part seems to be recommended while performing infrequent and forceful gripping tasks under the consideration of prevention, but there should be more information about the application of a splint without volar part while performing a repetitively gripping task.

Adolescent↗
PubMed2004

Upper limb mechanical changes following short duration repetitive eccentric exertions.

BACKGROUND: Power hand tool use is considered a risk factor for upper extremity musculoskeletal disorders. It is unclear if submaximal eccentric activity inherent to power tool use adversely affects the mechanical properties of muscle. METHODS: This study investigated in vivo changes in human upper limb dynamic mechanical properties following exposure to short-term repetitive submaximal eccentric exertions that are similar to operating an industrial power hand tool. Eighteen subjects (12 males and 6 females) were assigned to one of three exercise groups (isometric, eccentric or control) and exercised 10 min for 60 repetitions at 50% of isometric forearm supination maximum voluntary contraction. Supination strength and dynamic mechanical properties (stiffness, effective mass, and damping) of forearm rotation, modeled as a single-degree-of-freedom system during maximal exertion, were ascertained prior to exercise, immediately following exercise and 24 h later. FINDINGS: Strength decreased for the isometric (17%) (P < 0.05) and eccentric (34%) (P < 0.01) groups following exercise. Only the eccentric exercise group had a reduction in mechanical stiffness (53%) (P < 0.01) and effective mass (58%) (P < 0.05). The other groups had no changes in mechanical properties. INTERPRETATION: The change in mechanical properties following repetitive submaximal eccentric activity could negatively impact the ability of the arm to react to rapid forceful loading during repetitive industrial work activities and may indicate mechanical strain on the upper limb.

Adaptation, Physiological↗
PubMed2004

Differences in motor recruitment and resulting kinematics between low back pain patients and asymptomatic participants during lifting exertions.

BACKGROUND: Low back disorders are a prevalent problem in society today and may lead to chronic debilitating low back pain. Developing our understanding of temporal muscle and kinematic patterns during manual material handling tasks may provide insight for preventing the cascading series of events leading to chronic low back pain. METHODS: Sixty-two low back pain patients and 61 asymptomatic participants performed a variety of lifting exertions that varied in lift origin horizontal and vertical distance, lift asymmetry, and weight. Electromyographic activity of 10 trunk muscles as well as trunk and pelvic kinematics was recorded during each exertion. Differences in muscle activation and kinematic parameters were compared between low back pain patients and asymptomatic participants as a function of experimental conditions. FINDINGS: Both the left and right erector spinae activated significantly earlier and were on significantly longer in low back pain patients compared to asymptomatic participants. The horizontal and vertical location of the lift influenced the EMG and kinematic differences between the low back pain patients and asymptomatic participants. INTERPRETATION: These finding indicate that low back pain patients would be exposed to increase muscle activity resulting in higher spine loads for a greater length of time compared to asymptomatic participants. The longer exposure time to increased spine load may lead to greater risk of future low back injury and cascading events leading to debilitating low back pain. The longer muscle activation time suggests that low back pain patients have changed their motor program from an open to a closed loop system.

Adult↗
PubMed2006

Exertional changes in circulating cardiac natriuretic peptides in patients with suggested coronary artery disease.

BACKGROUND: We measured plasma brain natriuretic peptide (BNP) and N-terminal atrial natriuretic peptide (ANP) levels before and after exercise stress testing and correlated results with echocardiographic evidence of ischemia. METHODS: Sixty patients with left ventricular ejection fraction greater than 50% referred for clinically indicated exercise echocardiogram were studied. Peptides were measured at rest and 5 minutes after symptom-limited exercise. RESULTS: Echocardiography was positive for ischemia in 19 (32%). With exercise, ANP level increased in all 60 patients (median at rest 2501 [799-6440]-3167 [977-8563] pg/mL after exercise [P < .0001]). BNP increased in 54 patients (90%) (19 [<3.9-213]-30 [<3.9-318] pg/mL [P < .0001]). In multivariable analysis, both exercise BNP level and exertional change in BNP were closely associated with rest BNP (P < .0001); both were also significantly associated with change in wall-motion score index and workload (P = .001 and P = .01, respectively). Exercise ANP was strongly related to rest level (P < .0001); change in ANP was related to workload (P < .0001). CONCLUSION: In patients with suggested coronary artery disease, exertional levels of BNP are influenced not only by development of stress-induced ischemia, but also by resting levels.

Aged↗