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 181 records · Page 10Linked to original sources
PubMed1991

Human strength capabilities during one-handed maximum voluntary exertions in the fore and aft plane.

Maximal static strengths were determined for one-handed exertions in all directions in the fore and aft plane. Data from 12 males and 10 females (mean age 30.7 yrs, standard deviation (SD) = 8.9 yrs, n = 22) were obtained with handle heights of 1.0 and 1.75 m. Twelve of the subjects also performed two-handed exertions at the same handle heights. The ratio of mean strengths of females to that of males ranged from 0.50 to 0.83 (for absolute forces) and from 0.63 to 1.00 for forces normalized to body weight. The ratios of one-handed to two-handed strengths ranged from 0.64 to 1.04. Two-handed strengths commonly exceeded one-handed strengths at the lower handle height, but showed fewer significant strength differences (p less than 0.05) according to direction at 1.75 m. Both female/male and one-handed/two-handed strength ratios were found to be dependent on direction of exertion and handle height. The observed strength dependencies upon number of hands (one or two-handed), direction of exertion, handle height and sex are discussed. The strength data have implications for use in biomechanical models and task analysis.

Adult↗
PubMed1997

A comparison of risk assessment of single and combination manual handling tasks: 2. Discomfort, rating of perceived exertion and heart rate measures.

Although many manual handling activities involve combinations of pull, lift, carry, lower and push, there are few reports of investigation of how to assess the risk in these combination tasks. Two strategies have been suggested in the literature for estimating the risk in a combination task based on the measures of the separate components of that task. The aim of the study was to compare the risks assessed in single manual handling tasks with those in combination tasks. Ratings of discomfort, exertion and heart rate were collected from nine male and nine female students, performing combination and single tasks. Combination tasks consisted of sequences of pull, lift, carry, lower and push tasks. Combination tasks were performed at 1.min-1 and 3.min-1 whilst single tasks (lift, lower, push, pull and carry) were performed at 3.min-1 and 6.min-1. The rating of exertion and heart rate for each combination task was compared to the exertion rating and heart rate of the single tasks which comprised the combination task using repeated measures analysis of variance with specified contrasts. Similar comparisons for the discomfort data were performed using Friedman and Wilcoxon tests. In at least one of the twelve comparisons performed for each dependent variable, the combination task value was significantly different to each single task value. The differences occurred regardless of whether the most critical single task value or an average of all single task values was used. It was concluded that the risk in combination manual tasks can not be accurately assessed by using estimates from discomfort, exertion ratings and heart rate measures of single tasks.

Analysis of Variance↗
PubMed1996

Ratings of perceived exertion by women with internal or external locus of control.

Ratings of perceived exertion are frequently used to estimate the strain and effort experienced subjectively by individuals during various forms of physical activity. A number of factors, both physiological and psychological in origin, have been suggested to work as modifiers of the exertion perceived by the individual. It has been reported in nonsport-related research that individuals with an internal locus of control seem to pay more attention to relevant information and use the available information more adequately than individuals with an external locus of control. The reputed inferior information-processing abilities of externals compared with internals could possibly also influence the ratings of perceived exertion, with externals being less accurate in their ratings. Whether locus of control might be such a factor was investigated. Fifty women worked on an ergometer cycle at four different work loads. The results showed statistically significant differences in subjective ratings of perceived exertion between externals and internals, especially at heavier work loads. Such differences might be because of unequal information-processing abilities, as the observed discrepancies occurred at higher work intensities, when more cues are available for processing.

Adult↗
PubMed1998

Central, local, and overall ratings of perceived exertion during cycling and running by women with an external or internal locus of control.

Much research has been directed toward finding the most prominent psychological factors affecting ratings of perceived exertion during physical exercise. The one most frequently mentioned, although rarely investigated empirically, is locus of control. Findings from non-sport-related research indicate that individuals with an internal locus of control (internals) are better at using the available information than individuals with an external locus of control (externals). That finding has been attributed to the inferior information-processing capacity of the latter group, a deficit that might also affect the processing of exertional cues during physical exercise. In the present study, a group of women categorized as internals were compared with a similar group of externals during both ergometer cycling and treadmill running. The results indicated significantly different ratings between the groups not only for overall perceived exertion but also for local (muscles and joints) and central (cardiopulmonary) exertion. The observed differences were greater during ergometer cycling than during treadmill running. It is possible that the more distinct cues available during cycling, stemming mainly from the working muscles (local factors), presented more information to process, a task that the internals were better at than the externals.

Adult↗
PubMed2002

Criterion-related validity of the Borg ratings of perceived exertion scale in healthy individuals: a meta-analysis.

The literature related to Borg's ratings of perceived exertion (RPE) scale has revealed inconsistencies about the strength of the relationship between ratings of perceived exertion and various physiological criterion measures, such as heart rate, blood lactate concentration, percent maximal oxygen uptake (%VO2max), oxygen uptake (VO2), ventilation and respiration rate. Using sex of participants, fitness, type of RPE scale used, type of exercise, exercise protocol, RPE mode and study quality, we undertook a meta-analysis to determine the strength of the relationship between RPE scores and the six aforementioned physiological measures. The weighted mean validity coefficients were 0.62 for heart rate, 0.57 for blood lactate, 0.64 for %VO2max 0.63 for VO2, 0.61 for ventilation and 0.72 for respiration rate. Analysis of moderator variables revealed that the following study features could account for the variation of results across studies: heart rate--fitness, type of exercise, protocol and RPE mode; blood lactate concentration--sex, RPE scale; VO2--sex, exercise type, RPE mode; ventilation--sex, RPE mode; respiration rate--exercise protocol, RPE mode. The highest correlations between ratings of perceived exertion and the various physiological criterion measures were found in the following conditions: when male participants (whose VO2 or ventilation was measured) were required to maximally exert themselves (measuring %VO2max or ventilation); when the exercise task was unusual [e.g. when participants were swimming, which is less common than walking or running (when heart rate, %VO2max and VO2 are measured)]; or when the 15-point RPE scale (measuring blood lactate concentration) was used. These findings suggest that although Borg's RPE scale has been shown to be a valid measure of exercise intensity, its validity may not be as high as previously thought (r = 0.80-0.90), except under certain conditions.

Adolescent↗
PubMed1993

Effect of tool shape and work location on perceived exertion for work on horizontal surfaces.

Thirty subjects drove screws into perforated sheet metal mounted on a horizontal surface using three air-powered tools that varied in shape (right-angle, in-line, and pistol-shaped). The four horizontal work locations ranged from 13-88 cm in front of the body and were placed at 25 cm intervals. The vertical placement of the horizontal beam was at midthigh, elbow, and midchest height. Subjects drove 25 screws at each tool/work location combination before rating that condition using the Borg 10-point ratio rating scale. The ratings of perceived exertion increased with increasing horizontal distance from the body. When tool shape was not considered, the perceived exertion was virtually equal for driving screws at midthigh or elbow height. The ratings at midchest height were significantly higher than elbow and midthigh height. When tool shape was taken into account, subjects perceived less exertion driving screws with the pistol-shaped tool at midthigh height. The in-line and right-angle tools had the lowest ratings of perceived exertion for driving screws at elbow and midchest height.

Adolescent↗
PubMed1988

Aerobic exercise training reduces resting and exertional blood pressure in cardiac patients.

We evaluated the effects of exercise training (ET) on resting and exertional blood pressure in patients with cardiac disease. ET consisted of 20 to 30 minutes of aerobic activity three times weekly for 12 months. The study group comprised 17 males and three females (mean age 58 years, range 40 to 71 years). Blood pressure was evaluated at rest and during exercise after 6 and 12 months ET. A training effect was documented by an increase in functional capacity from 7.5 METs (1 MET = 3.5 mL oxygen consumption/kg/min) pre-ET to 8.8 and 9.2 METs after 6 and 12 months, respectively. The following significant (P less than 0.05) effects occurred on blood pressure in association with ET: resting systolic pressure pre-ET decreased from 131 to 124 mm Hg at 12 months ET; submaximal (50% pre-ET maximum capacity) systolic and diastolic pressures decreased from 150/84 to 142/80 mm Hg (6 months ET) and 144/80 mm Hg (12 months ET); diastolic pressure at maximal exertion fell from 83 to 77 mm Hg (6 months ET) and 78 mm Hg (12 months ET). Systolic blood pressure at maximal exertion was not increased despite significant increases in peak workload achieved at 6 and 12 months ET. Therefore, ET not only enhances functional capacity in cardiac patients but may be associated with a beneficial cardiac effect through attenuation of both rest and exertional blood pressure.

Adult↗
PubMed2001

Adult isolated hypoplasia of left pulmonary artery with exertional angina and abnormal exercise stress test: a case report and treatment implication.

Pulmonary artery hypoplasia, either congenital or acquired, is a rare abnormality seen in adults. We reported the first case of adult, isolated, left pulmonary artery hypoplasia, with exertional angina and prominent ST depression in exercise stress test, that seemed to be caused by exertional hypoxemia. Several vasodilators, including nitroglycerin, prostaglandin E1, and nifedipine, were administered individually, each with subsequent hemodynamic monitoring, pulse oximetric monitoring, and exercise test. Vasodilator administrations reduced pulmonary vascular resistance (baseline, 599; vasodilators, 306, 211, and 284 dyne x sec x m2/cm5, respectively) and attenuated ST depression (by 52, 72, and 27%, respectively) but without an immediate benefit on exercise tolerance. All vasodilators except nifedipine ameliorated exertional hypoxemia (expressed by arterial oxygen saturation during peak exercise, baseline, 69%; vasodilators, 85, 78, and 65%, respectively). Additional oxygen supply after nitroglycerin administration further benefited exertional hypoxemia (arterial oxygen saturation, 96%) and exercise ST depression (attenuated by 82%).

Angina Pectoris↗
PubMed1994

Physical exertion as a risk factor for spontaneous abortion.

This study examined the association of physical exertion and spontaneous abortion in a case-control study of 607 women whose pregnancies ended in spontaneous abortion and 1,287 women who delivered livebirths in Santa Clara County, CA, in 1986 and 1987. We interviewed women about the number of hours they spent doing heavy housework and caring for young children. We also interviewed women employed during their pregnancies (71% in each group) about their work schedule; the number of hours they worked, stood, commuted, and stooped or bent; and the number of times per day they lifted weights of > 15 pounds. Standing > 8 hours per day at work was the only variable associated with increased risk [adjusted odds ratio (OR) = 1.6; 95% confidence limits (CL) = 1.1, 2.3]. This association was present only for women with a history of spontaneous abortion (adjusted OR = 2.8; 95% CL = 1.4, 5.9). Among women with this history, the OR for a second trimester abortion was 4.9 (95% CL = 1.9, 12.2). Cleaning house for > 7 hours per week or caring for young children for > 50 hours per week was associated with decreased risk (adjusted OR = 0.6, 95% CL = 0.5, 0.9; adjusted OR = 0.8, 95% CL = 0.6, 1.0, respectively). Again, these associations were specific to women with a history of spontaneous abortion (adjusted OR = 0.4, 95% CL = 0.2, 0.7; adjusted OR = 0.5, 95% CL = 0.3, 0.8). These results indicate that the specific type of physical exertion, the amount of exertion, and the context of the exertion may be important.

Abortion, Spontaneous↗
PubMed1996

Cerebral activation during the exertion of sustained static force in man.

The aim of our study was to determine alterations of cerebral activity during prolonged static force exertion. Regional cerebral blood flow (rCBF) was measured using H2(15)O positron emission tomography (PET) while six male normal subjects pressed a morse-key with their right index finger with a constant force of 20% of their maximal voluntary contraction (MVC) for different periods of time (1.5-4.5 min). Exertion of static force led to activation which was at least as extensive as that during exertion of repetitive dynamic force pulses. Despite a considerable sense of fatigue and increased effort at the end of a 4.5 min key press, no compensatory changes of activity were detected in motor or sensory related structures. The right dorsolateral prefrontal cortex demonstrated a significant correlation between rCBF and duration of key-press, possibly reflecting processes over-riding fatigue. Prominent basal ganglia activation was demonstrated in this static force task, but not in a previous force task involving repetitive dynamic force pulses. This suggests that sustained exertion of a static force is an active process modulated, at least in part, by the basal ganglia.

Adult↗
PubMed1996

Exertional compartment syndromes of the lower extremity.

Compartment syndromes may be acute or chronic secondary to exertion or exercise. The chronic or exertional type most commonly involves the lower extremity, particularly the anterior compartment of the lower leg, and is the subject of this review. Rarely, an exertional compartment syndrome may become acute. The diagnosis is based on history, physical examination, and compartment pressure measurements. The differential diagnosis of exertional leg pain includes stress fractures, stress reaction, periostitis, claudication, popliteal artery entrapment, and peripheral nerve entrapment. Unusual causes, such as a ganglion of the proximal tibiofibular joint causing an anterior compartment syndrome, have recently been reported.

Compartment Syndromes↗
PubMed2002

Exertional myelopathy in type 2 congenital kyphosis.

STUDY DESIGN: A case of lower-extremity myelopathy induced by physical exertion in a patient with Type 2 (failure of segmentation) congenital kyphosis is reported. OBJECTIVE: To describe the uncommon presentation of neurologic sequelae in a patient with Type 2 congenital kyphosis. SUMMARY OF BACKGROUND DATA: Various reports have described neurologic sequelae in patients with Type 1 (failure of formation) congenital kyphosis. To the authors' knowledge, no case of Type 2 congenital kyphosis leading to neurologic symptoms has been reported. METHODS: A 17-year-old boy presented with a 3-year history of progressively worsening midthoracic back pain. During exertion, numbness developed along the posterior aspects of his legs, and he experienced a wobbly sensation in his lower extremities that prevented his participation in athletic activities. His static and dynamic neurologic examination was unremarkable. However, he developed a wide-based clumsy myelopathic gait when he was asked to run in the halls of the clinic. Magnetic resonance imaging demonstrated that the spinal cord was draped over the posterior vertebral body of T10. Anterior thoracic spinal cord decompression and fusion were performed through a seventh rib thoracotomy using a structural rib graft to fill the defect. The anterior 1 cm of bone was left intact so as not to cause any additional instability. RESULTS: The patient tolerated the procedure well and had complete resolution of his exertionally dependent myelopathic symptoms. At this writing, 3 years after surgery, he is involved in the Navy ROTC program. CONCLUSIONS: Although Type 2 congenital kyphosis is a rare entity, it should be followed carefully and corrected surgically when appropriate. A history of exertional myelopathy may be an early sign of spinal cord impingement and is an indication for surgical decompression.

Adolescent↗
PubMed2006

Changes in posture and perceived exertion in adolescents wearing backpacks with and without abdominal supports.

OBJECTIVE: The goal was to examine whether backpacks with an abdominal support device improve posture and decrease exertion while walking among adolescents. DESIGN: Double-blinded trial, with 20 subjects, performed at a University Spine Center. On day 1, adolescents walked on a treadmill for 5 mins with photographic measurement of posture and responded to the Borg scale of perceived exertion before and after ambulation. On day 2, they repeated the trial four more times wearing a backpack randomly loaded with either 10% or 20% of body weight and with or without the Back Balancer abdominal support. Postural measures were recorded by a blinded observer. RESULTS: Postural changes (forward lean) wearing a backpack with abdominal support were significantly lower while carrying both 10% and 20% of body weight (P = 0.024 and P = 0.008, respectively) vs. no abdominal support. In addition, perceived exertion at 10% and 20% of body weight was significantly greater without abdominal support (P = 0.042 and P = 0.018, respectively). CONCLUSIONS: Forward lean and perceived exertion while wearing backpacks in adolescents can be significantly decreased with abdominal support. This may increase comfort and decrease complications, such as back pain, that may arise from backpack use.

Abdomen↗
PubMed1990

Work-related physical exertion and risk of preterm, low birthweight delivery.

Although many women work during pregnancy, the effect of maternal job experience on pregnancy outcome is controversial. We investigated whether work-related physical exertion increases a woman's risk of delivering a preterm, low birthweight infant. We studied 773 employed, pregnant women included in the National Longitudinal Survey of Labor Market Experience, Youth Cohort (NLSY), a nationally representative sample of young adults. Data concerning work status, job title during pregnancy, and other factors affecting the outcome of pregnancy were obtained from the NLSY. Assessment of physical exertion was based on job title, using an established catalogue of occupational characteristics. Women in jobs characterised by high physical exertion experienced a higher rate of preterm, low birthweight delivery, defined as maternal report of delivery more than 3 weeks early and birthweight under 2,500 g (adjusted RR = 5.1, 95% CI = 1.5, 17.7). These findings support a policy of limiting work-related physical exertion during pregnancy.

Adolescent↗
PubMed1986

Blood flow to the respiratory and limb muscles and to abdominal organs during maximal exertion in ponies.

Using radionuclide-labelled microspheres, 15 micron in diameter, we studied blood flow in the respiratory muscles (diaphragm and intercostal muscles), abdominal organs (adrenal glands, kidneys, pancreas, spleen and the small and large intestines), muscles of propulsion (gluteus medius and biceps femoris), and other working (triceps brachii and longissimus dorsi lumborum) and non-working (temporal and masseter) muscles of ponies at rest and during maximal exercise performed on a treadmill. During maximal exercise heart rate, whole body O2 consumption, cardiac output and mean aortic pressure increased 4.4-fold, 38-fold, 8-fold and 1.5-fold of their resting values, respectively. During maximal exertion arterial CO2 tension and arterial pH decreased while arterial O2 content increased by 58% due to a 59.6% rise in haemoglobin concentration. Arterial O2 tension decreased somewhat and the calculated alveolar to arterial O2 tension gradient widened during exertion. During maximal exertion blood flow in the adrenal glands increased while that in the kidneys, spleen, pancreas, small intestine and colon decreased precipitously. Thus ponies exhibited intense vasoconstriction in the renal and splanchnic vascular beds, similar to that reported in man but not in exercising dogs. During maximal exertion stride (and hence respiratory) frequency of galloping ponies was 138 +/- 3 min-1, and the blood flow and O2 delivery in the diaphragm were not different from those in other strenuously working muscles, namely gluteus medius, biceps femoris (muscles of propulsion) and triceps brachii. Blood flow in the intercostal muscles was only 54% of that in the diaphragm at rest, but with maximal exercise it registered a marked increment and the perfusion became similar to that in the longissimus dorsi lumborum, a powerful extensor of the back and loins.

Abdomen↗
PubMed1975

Exertion and acute coronary artery injury.

Twelve cases of myocardial infarction as related to strenuous exertion are presented with the pathological findings in several of these cases. Three cases with coronary arteriography are also presented. The pathology of coronary arteriosclerotic plaques and the vulnerability to acute injury is reviewed and discussed. It is concluded that strenuous exertion can cause acute injury to coronary artery plaques due to the unusual stressful whip-like action to which coronary arteries are subject. These injuries may initiate as cracks in the plaques or subintimal hemorrhages and proceed to coronary occlusion and ultimate myocardial infarction. With this concept in mind we use the term of "crack in the plaque" (Black's Crack in the Plaque) to account for the sudden appearance of clinical coronary artery disease appearing during or shortly after exertion, or other stressful situations in patients without previous existing evidence of clinical coronary artery disease. This could also account for exacerbation of symptoms or death occurring after exertion in previously quiescent asymptomatic known coronary artery disease subjects. This concept may explain some of the puzzling features of coronary disease.

Adult↗
PubMedDate not supplied

The tibialis posterior muscle compartment. An unrecognized cause of exertional compartment syndrome.

Exertional compartment syndrome in the deep posterior compartment of the leg is well recognized. This paper reports investigations which were performed to prove that the tibialis posterior muscle is contained in its own osseofascial compartment, separate from the rest of the deep posterior compartment. Radiographs following the injection of radio-opaque dye into the tibialis posterior muscle demonstrated the fluid-impermeable, osseofascial boundaries surrounding this muscle. Compartment syndromes created in cadaver legs reveal that traditional techniques of fasciotomy of the deep posterior compartment are inadequate in decompressing the tibialis posterior muscle. Intracompartmental pressure measurements in athletes with a clinical diagnosis of exertional compartment syndrome proved the existence of isolated exertional compartment syndrome in the tibialis posterior muscle. From these results we may conclude that the tibialis posterior muscle is contained in a separate osseofascial muscle compartment which may be the site of an isolated exertional compartment syndrome and that common techniques of fasciotomy of the deep posterior compartment do not decompress the tibialis posterior muscle.

Adult↗
PubMed1994

Responses to preferred intensities of exertion in men differing in activity levels.

We compared ratings of perceived exertion (RPE), state anxiety, percentage of peak oxygen uptake (% VO2peak), percentage of ventilatory threshold (% Tvent), and blood lactate concentration [HLa] in 11 high-active and 12 low-active men (23 +/- 3 yr) at self-selected power outputs during 20 min of cycling. The high-active group selected higher power outputs than did the low-active group, but % VO2peak and % Tvent were lower for the high-active subjects during the initial 5-10 min of cycling. Both groups reported increased RPE across time, but contrary to past studies of load-incremented cycling, RPE was identical for the groups despite their differences in relative intensity. No differences were found for [HLa] or state anxiety during cycling. The groups did not differ on exertional symptoms, but the high-active subjects reported a significant reduction in state anxiety immediately after cycling. A preferred exertion protocol provides an alternative approach to identifying influences on perceived exertion during prolonged exercise. The influence of physical activity history/status on the association between the concomitant pattern of self-selected power outputs and postexercise anxiety reduction merits study.

Adolescent↗