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PubMed2002

Exertional compartment syndrome and the role of magnetic resonance imaging.

A 47-yr-old woman presented with a 1-yr history of progressive bilateral anterior lower leg pain and swelling with walking, which resolved 10 min after activity. Postexercise (forced dorsiflexion) magnetic resonance imaging revealed increased T2 signal intensity in the entire anterior muscle compartment, and anterior compartment pressures were elevated at rest and postexercise. Chronic exertional compartment syndrome can occur in some patients after even minimal physical activities, and magnetic resonance imaging without the use of radioisotopes was a useful adjunct for diagnosis.

Anterior Compartment Syndrome↗

PubMed1984

Muscle localization of Tc-99m MDP after exertion.

Very high muscle uptake of Tc-99m MDP was seen two days after the start of a program of vigorous weight-lifting exercises. Localization of Tc-99m bone tracer in muscle that has been damaged by exertion may be a more common phenomenon than is recognized at present.

Adult↗

PubMed2002

People with intellectual disabilities: activities, social contacts and opportunities to exert influence (an interview study with staff).

The aim of this article is to describe the relationship between activities, social network and the possibility of influencing daily lives for about 24 people with intellectual disabilities. The study is based on data collected through interviews with staff at day centres and in group homes and with one relative. The results indicated that several of the people with intellectual disabilities had little or no opportunity to exert influence on choice of activities or social contacts. The study also suggests that if the environment makes it possible for people with intellectual disabilities to make choices, learn social competence and technical know-how and to communicate, it will support the opportunity for choosing activities, participating and influencing. Increased possibilities for communication are one way of changing the balance of power. An important factor for the participants was relatives and contact people, those participants who have these had more variation in their activities and in more different environments. The study shows that it is important to offer different experiences to people with intellectual disabilities in order that they learn to take initiatives and try new things.

Adult↗

PubMed1995

Endogenous adenosine attenuates myocardial stunning by antiadrenergic effects exerted during ischemia and not during reperfusion.

The effect of adenosine receptor blockade and adrenergic blockade on myocardial stunning [left anterior descending coronary artery (LAD) occluded for 10 min and reperfused for 180 min] was studied in 38 open-chest cats. A control group (Control) was compared with two other groups in which adenosine receptors were blocked by 8-phenyltheophylline (7.5 mg/kg) before reperfusion (8-PT-R) or before ischemia (8-PT-I). Group A, in which adrenergic receptors were blocked (doxazosin 200 micrograms/kg + propranolol 1 mg/kg), was compared with group A + 8-PT-I, in which both adenosine and adrenergic receptors were blocked before coronary artery occlusion. Regional systolic function assessed by sonomicrometry in the LAD perfused area recovered less in 8-PT-I (55 +/- 5% recovery) as compared with Control (87 +/- 9%) and 8-PT-R (89 +/- 8%), which indicates that adenosine receptor blockade during ischemia increases stunning. Functional recovery was similar in Control, group A (96 +/- 5%), and group A + 8-PT-I (87 +/- 5%), which demonstrates that if adrenergic receptors are blocked, adenosine receptor blockade during ischemia does not increase stunning. These results may indicate that the cardioprotective effects of endogenous adenosine are mediated through antiadrenergic effects exerted during coronary artery occlusion.

Adenosine↗

PubMed1996

The validity of regulating blood lactate concentration during running by ratings of perceived exertion.

We examined whether ratings of perceived exertion (RPE) observed during an incremental (response) protocol could be used to produce target blood [HLa] of 2.5 mM and 4.0 mM during a 30-min treadmill run at a constant RPE. RPE (15.3, 17.6, 19.1), oxygen uptake (VO2) (3.31, 3.96, 4.00 l.min-1), velocity (V) (198, 218, 223 m.min-1), and heart rate (HR) (179, 185, 190 bpm) at blood [HLa] of 2.5 mM and 4.0 mM, and peak were determined for nine subjects (5 males, 4 females) during incremental exercise. Subjects then completed two 30-min runs at the RPE corresponding to blood [HLa] of 2.5 mM (RPE 2.5 mM) and 4.0 mM (RPE 4.0 mM) measured during the incremental protocol. For both 30-min runs, VO2 was not different from VO2 corresponding to either 2.5 or 4.0 mM blood [HLa] during the incremental test. During the 30-min run at RPE 2.5 mM: (a) only during minutes 25-30 was the blood [HLa] significantly different than 2.5 mM (3.2 +/- 0.6 mM, P < 0.05), (b) for the first 20 min HR was significantly lower than the HR at 2.5 mM during the incremental protocol, and (c) V did not differ from V at 2.5 mM during the incremental protocol. During the 30-min run at RPE 4.0 mM: (a) blood [HLa] was not significantly different from 4.0 mM, (b) HR at every time point was significantly lower than HR 4.0 mM during the incremental protocol, and (c) V was decreased over time by an average of 24.6 m.min-1 (P < 0.05). Because RPE from the response protocol was able to produce a blood [HLa] close to the criterion value during each 30-min run, we conclude that RPE is a valid tool for prescribing exercise intensities corresponding to blood [HLa] of 2.5 mM and 4.0 mM.

Adult↗

PubMed1997

Blood lactate and perceived exertion relative to ventilatory threshold: boys versus men.

The purpose of this study was to examine blood lactate (BLa) levels and ratings of perceived exertion (RPE) in nine boys (10.5 +/- 0.7 yr) and nine men (25.3 +/- 2.0 yr) during exercise relative to ventilatory threshold (VT). VT and VO2max were determined during a graded exercise test on a cycle ergometer. On three additional days each subject exercised for 10 min at either 80, 100, or 120% of the VO2 at VT. Capillary BLa levels and RPE were assessed at minutes 5 and 10 of each trial. VO2max averaged 47.7 +/- 5.4 and 50.2 +/- 6.2 mL x g(-1) x min(-1) in the boys and men, respectively (P > 0.05). VT expressed as %VO2max was 67.2 +/- 3.5% in the boys and 67.3 +/- 4.9% in the men (P > 0.05). BLa levels ranged from 2.0 +/- 0.7 to 4.7 +/- 0.9 mmol x L(-1) in the boys and from 2.6 +/- 0.5 to 8.2 +/- 2.1 mmol x L(-1) in the men across the three intensities. Corresponding RPE values ranged from 11.2 +/- 1.8 to 16.2 +/- 2.2 in the boys and from 10.2 +/- 1.2 to 15.8 +/- 1.7 in the men. A group x time x intensity interaction (P < 0.05) indicated that BLa in the men increased more so across time and intensity. There were no significant group difference or interactions involving RPE during exercise. Setting exercise intensity relative to VT did not abolish child-adult differences with respect to submaximal BLa levels. Despite maintaining lower BLa levels, RPE values were similar between boys and men.

Adult↗

PubMed1998

Perceived exertion and the preferred cycling cadence.

PURPOSE: To determine whether an association exists between peripheral comfort level, as reflected by differentiated RPE measures, and the preferred cadences of subjects who differed in cycling experience and fitness level. METHODS: Twelve experienced cyclists (C), ten runners (R), and ten less-trained noncyclists (LT), all of whom were male, pedaled at three power outputs (C, R: 100, 150, 200 W; LT: 75, 100, 150 W) and six cadences (50, 65, 80, 95, 110 rpm, and their freely chosen cadence) for 5 min per condition. Differentiated ratings of perceived exertion (RPE) were recorded during the fifth minute of the exercise. It was hypothesized that the preferred cadence selected by C, R, and LT would be the same as the cadence at which the peripheral RPE was minimized. Comparison of means failed to support this hypothesis. RESULTS: Irrespective of rating scale (peripheral, central, overall), the cadences at which RPE was minimized were lower than the preferred cadences, except for LT at 150 W, where there was no significant difference between the preferred cadence and the cadences at which the peripheral and overall RPE were minimized. C tended toward a more curvilinear RPE-cadence relationship compared with R and LT. Mean data for all groups showed that only the peripheral RPE decreased from 50 to 65 rpm, whereas peripheral, overall, and central RPE remained essentially unchanged from 65 to 80 rpm but increased from 80 to 110 rpm. There was a trend for the cadences at which RPE was minimized for C to be higher than the cadences that minimized RPE in either R or LT. For all groups, the cadences at which peripheral RPE was minimized were significantly higher than the cadences at which either the overall or central ratings were minimized. CONCLUSION: The small magnitudes of change in the RPE score across cadence, particularly in C and R, suggest that RPE may not be a critical variable in cadence selection during submaximal power output cycling.

Adaptation, Physiological↗

PubMed2002

Perceived exertion, electromyography, and blood lactate during acute bouts of resistance exercise.

PURPOSE: This study examined ratings of perceived exertion (RPE) during resistance exercise in women. In addition, changes in blood lactic acid and biceps muscle activity assessed using electromyography (EMG) were investigated as potential mediators of RPE during resistance exercise. METHODS: Twenty female volunteers (age, 25 +/- 4 yr) performed one set of biceps curl exercise at 30%, 60%, and 90% of their one-repetition maximum (1-RM). Total work was held constant by varying the number of repetitions during each of the three intensities. The three intensities were performed in random order. RPE responses were assessed for both the active muscle (RPE-AM) and the overall body (RPE-O) following each intensity. EMG data were collected from the biceps brachii muscle during each intensity. Blood samples were taken before and following the intensities and analyzed for blood lactic acid concentration. RESULTS: A two-factor repeated-measures ANOVA showed a significant RPE (region) x intensity interaction (P < 0.02). Both RPE-AM and RPE-O increased as the intensity of exercise increased. EMG activity increased significantly (P < 0.01) as the intensity of exercise increased. A two-factor repeated measures ANOVA performed on the blood lactate data showed a significant (P < 0.04) time x intensity interaction. Postexercise [Hla] was significantly greater (P < 0.01) at 90% 1-RM than at 30% 1-RM. No significant differences were found in [Hla] between 30% and 60% 1-RM, or between 60% and 90% 1-RM. CONCLUSION: These results indicate that monitoring RPE may be a useful technique for regulating resistance exercise intensity. Moreover, blood lactate and activity of the involved muscle may mediate the relation between RPE and resistance exercise intensity.

Adult↗

PubMed1988

Antiproliferative effects exerted by recombinant human tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) on human pancreatic tumor cell lines.

Modulation of the growth of human pancreatic cancer cell lines in vitro by recombinant human tumor necrosis factor-alpha (TNF-alpha) and recombinant human interferon-gamma (IFN-gamma) was investigated. TNF-alpha exerted antiproliferative effects on three of nine pancreatic cancer cell lines and WiDR colorectal cancer cells. When administered together with IFN-gamma TNF-alpha showed enhanced antiproliferative effects on a subset of the pancreatic cancer cell lines tested, including those found to be insensitive to treatment with TNF-alpha alone. Thus the antiproliferative effect achieved by a combined treatment with TNF-alpha and IFN-gamma exceeded that observed with either drug alone in seven of nine pancreatic cancer cell lines.

Cell Division↗

PubMed1989

Type of dietary lipids exerts a major influence on the secretory activity of the exocrine pancreas: medium-term studies.

A possible influence of the type of dietary lipids on the pancreas exocrine function was tested on rats. For this purpose, four groups of rats were fed on different diets comprising 5% of different types of lipids: fish oil, evening primose oil, hydrogenated beef tallow, and a mixture of fish oil and evening primose oil. After a 6 week feeding period, the secretory activity of the pancreas was measured. Under resting conditions, rats fed hydrogenated beef tallow release different proportions of amylase, lipase, and serine proteases as compared to rats fed unsaturated lipids. In stimulated conditions, there was no significant difference in the relative proportions of enzymes secreted by the pancreas among the different groups of rats but the secretory response to cerulein stimulation from rats fed saturated lipids was increased by more than 40%. These results demonstrate that the type of dietary lipids exerts a major influence on the secretory activity of the pancreas.

Animals↗

PubMed1997

When exercise goes awry: exertional rhabdomyolysis.

Exertional rhabdomyolysis occurs when exercise, often of the eccentric type, damages myofibrils and sarcolemma, with release of the enzyme creatine kinase and pigmented myoglobin into the serum. Severe muscle soreness and dark urine are the hallmark symptoms, and renal failure may develop. Formerly a disease of military recruits, it is now seen more often in exercisers. Although a genetic trait may predispose, the illness probably can be avoided by common sense behavior such as a gradual increase in exercise intensity, proper hydration before, during, and after exercise, and avoiding exercise in extremely hot or humid environments.

Adult↗

PubMed1998

Exertional rhabdomyolysis after recent coxsackie B virus infection.

Acute, exertional rhabdomyolysis typically follows strenuous exercise of the eccentric type, such as that which occurs during military training or repetitive weight lifting in unconditioned individuals. Complications can be significant and include compartment syndrome and acute renal failure due to myoglobinuria, especially in the setting of volume depletion. Rhabdomyolysis may also be precipitated by viral infections, usually influenza virus. I report an unusual case of a female patient who had acute rhabdomyolysis, complicated by compartment syndrome of both legs, after beginning an exercise regimen on a treadmill. The patient reported a viral-like illness several days before and was found to have a rise in antibodies to coxsackieviruses B4 and B5.

Acute Disease↗

PubMed1988

1988 Volvo award in biomechanics. The triaxial coupling of torque generation of trunk muscles during isometric exertions and the effect of fatiguing isoinertial movements on the motor output and movement patterns.

Previous studies have shown that reduction of precise motor control accompanies local muscular fatigue. The effects of isodynamic fatiguing of flexion and extension trunk movements on the movement patterns and the motor output of the trunk were investigated. Twenty male subjects with no history of low-back pain for the past 6 months volunteered for the study. A triaxial dynamometer was used that simultaneously provided measurement of torque, angular position and velocity of each axis. Resistances were set independently for each axis by an interfaced computer. The subjects performed trunk flexion and extension movement against a sagittal plane resistance equal to 70% of their maximum isometric extension strength in the upright position. The minimum resistances in the coronal and transverse planes were set up at 7 Newton meters. The subjects were asked to perform trunk movement as quickly and as accurately as possible while exerting the maximum efforts until exhaustion. Analysis of variance, the MANOVA procedure with a repeated measure design, was performed among the selected parameters of the first, middle and last three repetition cycles. The selected parameters are the trunk motor output and movement patterns; the total angular excursion, range of motion, maximum and average torque and angular velocity of the trunk. All the selected parameters were significantly reduced in the sagittal plane. Subjects displayed significantly less motor control and greater range of motion in the coronal and transverse planes in performing the primary task of flexion and extension. The reduction in the functional capacity of the primary muscles performing the required task is compensated by secondary muscle groups and the spinal structure is loaded in a more injury prone pattern, as identified by finite element models. In addition it is suggested that the fatigued muscles would be less able to compensate any perturbation in the load or position of the trunk. The repetitive loading results in a weakening of the viscoelastic passive elements of the spineless structure. The loss of ability to protect these weakened passive elements makes the spine susceptible to industrial and recreational injuries.

Adult↗

PubMed1993

Forces exerted during spinal manipulative therapy.

Spinal manipulative therapy has been widely recognized in the medical fields as a conservative treatment modality for spinal dysfunction and pain. Spinal manipulative therapy consists of an application of a thrusting force on a specific part of the spine in a well-defined direction. The magnitude of this force has been associated with positive treatment effects, such as realigning vertebral bodies, mobilizing spinal joints, relaxing back musculature through reflex pathways, and producing a respiratory burst. However, direct force measurements during spinal manipulative therapy in a clinically relevant situation have not been performed to date. The purpose of this study was to measure the forces exerted onto patients during spinal manipulative therapy on various locations of the spinal column. Force measurements were obtained using a thin, flexible pressure mat. The results indicate that peak and preload forces are considerably smaller for spinal manipulative therapy performed on the cervical spine compared to corresponding values obtained on the thoracic spine and sacroiliac joint. Furthermore, for treatments on the thoracic spine and sacroiliac joint, a significant relation was found to exist between preload and peak forces.

Biomechanical Phenomena↗

PubMed2001

Does renal mass exert an independent effect on the determinants of antigen-dependent injury?

The aim of this retrospective study was to determine whether nephron mass may exert a direct, independent effect on immunological tolerance. To this end, data corresponding to patients transplanted with en block pediatric kidneys (EBPK) (n=48) were compared with those of renal transplants with a low risk of hyperfiltration (LRH) comprised of recipients of a kidney from young donors (age 5-40 years) (n=173), and transplants with a high risk of hyperfiltration (HRH) comprised of patients who had received a graft from an elderly donor (older than 55 years) (n=91). All the patients had been subjected to the same immunosuppressive treatment. The median follow-up period was 54 months (6-127 months). The EBPK group showed lowest serum creatinine and highest creatinine clearance levels at each follow-up time. The rate of proteinuria >500 mg/day was 5.7% in EBPK, 7.4% in LRH, and 27.3% in HRH (P=0.000). The incidence of acute corticoresistant rejection was minor in EBPK (7.0% in EBPK, 21.3% in LRH, and 23.3% in HRH; P=0.04). Logistic regression analysis showed that the type of transplant was predictive of acute corticoresistant rejection [RR 5.33 (95% confidence interval (CI) 1.15-24.62) for HRH and RR 4.75 (95%CI 1.06-21.27) for LRH, P=0.03]. Multivariate analyses for graft failure due to chronic rejection and for graft failure due to acute rejection according to Cox's regression analysis demonstrated that HRH transplant was a significant predictive variable of both types of failure [4.08 (95%CI 1.27-13.04) for graft loss due to chronic rejection and 8.69 (95%CI 1.69-44.67) for graft loss due to acute rejection]. The present stratification of data according to nephronal mass would appear to indicate that the greater the mass, the lower the incidence of both acute and chronic rejection. This finding lends support to the hypothesis that a large mass of transplanted tissue relative to recipient mass may dampen the immune response.

Adult↗

PubMed1998

L-propionyl carnitine, an endogenous ester in fatty acid metabolism, exerts anti-shock and endothelial protective effects in rat splanchnic ischemia-reperfusion injury.

Splanchnic artery occlusion (SAO) results in a severe form of circulatory shock in which oxygen-derived free radicals play an important role. L-Propionyl carnitine (LPC), an endogenous ester that plays a crucial role in cellular fatty acid oxidation and metabolism, has been shown to exert a protective effect in myocardial ischemia/reperfusion injury. Our purpose was to investigate the effects of LPC in an SAO model of ischemia/reperfusion injury. Pentobarbital-anesthetized rats were subjected to 60 min of SAO followed by 120 min of reperfusion. An intravenous bolus of LPC (200 microg/kg) administered 2 min before reperfusion prolonged survival time (116+/-4 vs. 81+/-3 min in 1 mL/kg .9% NaCl vehicle, p < .01), increased survival rate (88 vs. 13.6%, p < .01), and attenuated the percent increase in hematocrits (27+/4% vs. 43+/-3%, p < .05), and the increases in tissue myeloperoxidase activity (1.76+/-.4 U/100 mg vs. 3.79+/-.2 U/100 mg, p < .05). In addition, LPC increased mean arterial blood pressures at 60 min (p < .05), 80 min (p < .05), 100 min (p < .05), and 120 min (p < .05) postreperfusion. Moreover, LPC markedly attenuated splanchnic artery endothelial dysfunction induced by SAO ischemia/reperfusion injury (maximal vasorelaxation to ACh, 74+/-2.7% vs. 57+/-1.9% in vehicle, p < .01). In this murine SAO model of ischemia/reperfusion injury, LPC affords significant protection that may be achieved through inhibiting leukocyte infiltration into intestinal tissue and preserving endothelial function, thereby decreasing microvascular permeability and maintaining tissue perfusion.

Animals↗

PubMed2000

Evaluation of outcomes in patients following surgical treatment of chronic exertional compartment syndrome in the leg.

OBJECTIVE: To evaluate outcomes in patients who had a fasciotomy performed on their leg(s) for chronic exertional compartment syndrome (CECS). DESIGN: A retrospective descriptive cohort study. SETTING: Tertiary care sport medicine referral practice. PATIENTS: A consecutive series of 62 patients surgically treated for CECS from January 1991 to December 1997. MAIN OUTCOME MEASURES: A questionnaire was designed and developed to assess pain (using a 100 mm visual analogue scale), level of improvement, level of maximum activity, satisfaction level, and the occurrence of reoperations. RESULTS: Fifty patients had anterior/lateral compartment involvement, 8 patients had deep posterior compartment involvement, and 4 patients had anterior/lateral/deep posterior compartment involvement. The demographics of the 39 respondents and 23 nonrespondents were similar. The mean percent pain relief of respondents was 68% (95% CI [confidence interval] = 54% to 82%). There was no relationship between percent pain relief and the documented immediate post exercise compartment pressures. A clinically significant improvement was reported by 26 of 32 (81%) anterior/lateral compartment patients and 3 of 6 (50%) patients with deep posterior compartment involvement. Patient level of activity after fasciotomy was classified as equal to or higher than before the operation with a lesser degree of pain by 28 of 36 (78%) patients, while 8 of 36 (22%) patients reported lower activity levels than before the operation. Of the patients reporting lower activity, seven were due to exercise related pain in the post operative leg(s) and one was due to lifestyle changes. Thirty of 38 patients (79%) were satisfied with the outcome of the operation. Four of 62 patients (6%) failed the initial surgical procedure and required revision surgery for exercise-induced pain. In addition, one of these individuals also had a sympathectomy and another had a neurolysis performed at the time of revision surgery. Three of the 62 (5%) patients had subsequent operations for exercise-induced pain on different compartments than the initial surgical procedure. One individual had an unsuccessful operative repair of a posttraumatic neuroma. Postoperative complications were reported by 5 of 39 (13%) patients in the additional comments section of the questionnaire. CONCLUSIONS: The majority of patients surgically treated for CECS experience a high level of pain relief and are satisfied with the results of their operation. The level of pain relief experienced by patients is not related to the magnitude of the immediate post exercise compartment pressures. Despite the possibility that some patients have less favorable outcomes, experience complications, or need subsequent operations, fasciotomy is recommended for patients with CECS as there is no other treatment for this condition.

Adult↗

PubMed2005

Exertional heat stroke in competitive athletes.

Exertional heat stroke (EHS) is a serious medical condition that can have a tragic outcome if proper assessment and treatment are not initiated rapidly. This article focuses on critical misconceptions that pertain to the prevention, recognition, and treatment of EHS, including 1) the randomness of EHS cases, 2) the role of nutritional supplements in EHS, 3) temperature assessment, 4) onset of EHS and the possible lucid interval, 5) rapid cooling, and 6) return to play. Exploration of these topics will enhance the medical care regarding EHS.

Body Temperature↗