Differential expression of muscle damage in humans following acute fast and slow velocity eccentric exercise

We sought to determine if the velocity of an acute bout of eccentric contractions influenced the duration and severity of several common indirect markers of muscle damage. Subjects performed 36 maximal fast (FST, n=8: 3.14 rad center dot s(-1)) or slow (SLW, n=7: 0.52 rad center dot s(-1)) velocity isokinetic eccentric contractions with the elbow flexors of the non-dominant arm. Muscle soreness, limb girth, plasma creatine kinase (CK) activity, isometric torque and concentric and eccentric torque at 0.52 and 3.14 rad center dot s(-1) were assessed prior to and for several days following the eccentric bout. Peak plasma CK activity was similar in SLW (4030 +/- 1029 U center dot l(-1)) and FST (5864 +/- 2664 U center dot l(-1)) groups, (p > 0.05). Both groups experienced similar decrement in all strength variables during the 48 hr following the eccentric bout. However, recovery occurred more rapidly in the FST group during eccentric (0.52 and 3.14 rad center dot s(-1)) and concentric (3.14 rad center dot s(-1)) post-testing. The severity of muscle soreness was similar in both groups. However, the FST group experienced peak muscle soreness 48 hr later than the SLW group (24 hr vs. 72 hr). The SLW group experienced a greater increase in upper arm girth than the FST group 20 min, 24 hr and 96 hr following the eccentric exercise bout. The contraction velocity of an acute bout of eccentric exercise differentially influences the magnitude and time course of several indirect markers of muscle damage.

Resistance training and reduction of treatment side effects in prostate cancer patients

Purpose: To examine the effect of progressive resistance training on muscle function, functional performance, balance, body composition, and muscle thickness in men receiving androgen deprivation for prostate cancer. Methods: Ten men aged 59-82 yr on androgen deprivation for localized prostate cancer undertook progressive resistance training for 20 wk at 6- to 12-repetition maximum (RM) for 12 upper- and lower-body exercises in a university exercise rehabilitation clinic. Outcome measures included muscle strength and muscle endurance for the upper and lower body, functional performance (repeated chair rise, usual and fast 6-m walk, 6-m backwards walk, stair climb, and 400-m walk time), and balance by sensory organization test. Body composition was measured by dual-energy x-ray absorptiometry and muscle thickness at four anatomical sites by B-mode ultrasound. Blood samples were assessed for prostate specific antigen (PSA), testosterone, growth hormone (GH), cortisol, and hemoglobin. Results: Muscle strength (chest press, 40.5%; seated row, 41.9%; leg press, 96.3%; P < 0.001) and muscle endurance (chest press, 114.9%; leg press, 167.1%; P < 0.001) increased significantly after training. Significant improvement (P < 0.05) occurred in the 6-m usual walk (14.1%), 6-m backwards walk (22.3%), chair rise (26.8%), stair climbing (10.4%), 400-m walk (7.4%), and balance (7.8%). Muscle thickness increased (P < 0.05) by 15.7% at the quadriceps site. Whole-body lean mass was preserved with no change in fat mass. There were no significant changes in PSA, testosterone, GH, cortisol, or hemoglobin. Conclusions: Progressive resistance exercise has beneficial effects on muscle strength, functional performance and balance in older men receiving androgen deprivation for prostate cancer and should be considered to preserve body composition and reduce treatment side effects.

Early alterations in serum creatine kinase and total cholesterol following high intensity eccentric muscle actions

Aim. The purpose of this experiment was to assess the levels of muscle soreness, serum total cholesterol (TC) and creatine kinase (CK) in the first 48 hours following fatiguing eccentric exercise performed with the triceps brachii. Methods. Eleven untrained male college students performed a total of 50 eccentric elbow extensions in 8 sets (6x7 and 2x4) with a load equal to 85% of their maximal concentric elbow extension strength. Isometric elbow extension strength, muscle soreness and circumference, and serum CK and TC concentrations were measured before, immediately after, and 2, 24 and 48 hours after the exercise. Results. Statistically reliable changes in isometric strength, serum CK and TC, muscle soreness and upper arm circumference occurred within the first 48 hours following eccentric exercise. Serum TC concentrations exhibited a very rapid (within 2 hours) reduction from pre-exercise values after eccentric exercise to a relatively stable concentration of approximately 85% of baseline. Conclusion. These results suggest that serum TC concentration may follow the time-course of reductions in force generating capacity more closely than other biochemical markers of muscle damage.

Outcome measurement in Australian rehabilitation environments

Objective: To determine the frequency and pattern of methods of outcome assessment used in Australian physical rehabilitation environments. Design: Postal survey. Methods: A questionnaire on service type, staffing, numbers of adults treated and outcome measures used for 7 conditions related to injury and road trauma as well as stroke and neuromuscular disorders was sent to 973 services providing adult physical rehabilitation treatment. Results: Questionnaires were completed by 440 service providers for a response rate of 45%, similar to that reported in a recent European survey reported in this journal. A small number of measures were reported as in use by most respondents, while a large number of measures were used by a few respondents. Measures of physical changes were used more frequently than those of generic well-being or quality of life. Ease of use and reporting to other professionals were cited as the most important reasons in selection of outcome measures. Conclusion: This Australian-wide survey detected considerable heterogeneity in outcome measurement procedures used in rehabilitation environments. While the goal of measurement may vary between providers and differ between conditions, the results highlight opportunities for harmonization, benchmarking and measurement of health-related quality of life.

Carbohydrate supplementation and alterations in neutrophils, and plasma cortisol and myoglobin concentration after intense exercise

The present study examined the effect of carbohydrate supplementation on changes in neutrophil counts, and the plasma concentrations of cortisol and myoglobin after intense exercise. Eight well-trained male runners ran on a treadmill for 1 h at 85% maximal oxygen uptake on two separate occasions. In a double-blind cross-over design, subjects consumed either 750 ml of a 10% carbohydrate (CHO) drink or a placebo drink on each occasion. The order of the trials was counterbalanced. Blood was drawn immediately before and after exercise, and I h after exercise. Immediately after exercise, neutrophil counts (CHO, 49%; placebo, 65%; P < 0.05), plasma concentrations of glucose (CHO, 43%; P

Plasma cytokine changes in relation to exercise intensity and muscle damage

The purpose of this study was to compare the effects of exercise intensity and exercise-induced muscle damage on changes in anti-inflammatory cytokines and other inflammatory mediators. Nine well-trained male runners completed three different exercise trials on separate occasions: ( 1) level treadmill running at 60% VO2max (moderate-intensity trial) for 60 min; (2) level treadmill running at 85% VO2max (high-intensity trial) for 60 min; (3) downhill treadmill running ( - 10% gradient) at 60% VO2 max (downhill running trial) for 45 min. Blood was sampled before, immediately after and 1 h after exercise. Plasma was analyzed for interleukin-1 receptor antagonist (IL-1ra), IL-4, IL-5, IL-10, IL-12p40, IL-13, monocyte chemotactic protein-1 (MCP-1), prostaglandin E-2, leukotriene B-4 and heat shock protein 70 (HSP70). The plasma concentrations of IL-1ra, IL-12p40, MCP-1 and HSP70 increased significantly (P< 0.05) after all three trials. Plasma prostaglandin E-2 concentration increased significantly after the downhill running and high-intensity trials, while plasma IL-10 concentration increased significantly only after the high-intensity trial. IL-4 and leukotriene B4 did not increase significantly after exercise. Plasma IL-1ra and IL-10 concentrations were significantly higher ( P< 0.05) after the high-intensity trial than after both the moderate-intensity and downhill running trials. Therefore, following exercise up to 1 h duration, exercise intensity appears to have a greater effect on anti-inflammatory cytokine production than exercise-induced muscle damage.

The effect of motor control exercise versus placebo in patients with chronic low back pain

Background: While one in ten Australians suffer from chronic low back pain this condition remains extremely difficult to treat. Many contemporary treatments are of unknown value. One potentially useful therapy is the use of motor control exercise. This therapy has a biologically plausible effect, is readily available in primary care and it is of modest cost. However, to date, the efficacy of motor control exercise has not been established. Methods: This paper describes the protocol for a clinical trial comparing the effects of motor control exercise versus placebo in the treatment of chronic non-specific low back pain. One hundred and fifty-four participants will be randomly allocated to receive an 8-week program of motor control exercise or placebo (detuned short wave and detuned ultrasound). Measures of outcomes will be obtained at follow-up appointments at 2, 6 and 12 months after randomisation. The primary outcomes are: pain, global perceived effect and patient-generated measure of disability at 2 months and recurrence at 12 months. Discussion: This trial will be the first placebo-controlled trial of motor control exercise. The results will inform best practice for treating chronic low back pain and prevent its occurrence.

The influence of antioxidant supplementation on markers of inflammation and the relationship to oxidative stress after exercise

Interest in the relationship between inflammation and oxidative stress has increased dramatically in recent years, not only within the clinical setting but also in the fields of exercise biochemistry and immunology. Inflammation and oxidative stress share a common role in the etiology of a variety Of Chronic diseases. During exercise, inflammation and oxidative stress are linked via muscle metabolism and muscle damage. Because oxidative stress and inflammation have traditionally been associated with fatigue and impaired recovery from exercise, research has focused on nutritional strategies aimed at reducing these effects. In this review, we have evaluated the findings of studies involving antioxidant supplementation on alterations in markers of inflammation (e.g., cytokines, C-reactive protein and cortisol). This review focuses predominantly on the role of reactive oxygen and nitrogen species generated from muscle metabolism and muscle damage during exercise and on the modulatory effects of antioxidant supplements. Furthermore, we have analyzed the influence of factors such as the dose, timing, supplementation period and bioavailability of antioxidant nutrients. (C) 2007 Elsevier Inc. All rights reserved.

The impact of a reduction in drug supply on demand for and compliance with treatment for drug dependence

Background: In early 2001, Australia experienced a sudden, dramatic and;sustained decrease in heroin availability that was accompanied by sharp increases in price and decreases in street level purity-the so-called heroin shortage. These unprecedented changes occurred in a context of widespread treatment availability, which made it possible for the first time to examine the impact of a sharp reduction in heroin supply in New South Wales (NSW) on entry to and adherence with treatment for heroin dependence. Given the evidence of drug substitution by some users. the current paper also examines the effects of the shortage on entry to treatment for other forms of drug dependence. Methods: Interrupted time-series analysis of the number of persons entering opioid pharmacotherapy and other treatment modalities in NSW for heroin dependence and for the treatment for other types of drug dependence. Findings: The heroin shortage was associated with a reduction in the number of younger persons entering opioid pharmacotherapy. There was a dramatic decrease in the number of persons entering heroin withdrawal or assessment only treatment episodes. There appear to have been small improvements in adherence to and retention in heroin treatment after the reduction in heroin supply. Relatively small increases were observed in numbers being treated for cocaine dependence. Conclusions: In the context of good treatment provision, a reduction in heroin supply appeared to produce modest improvements in intermediate outcomes. Supply and demand reduction measures, when both are implemented successfully, may be complementary. (c) 2005 Elsevier Ireland Ltd. All rights reserved.

Antioxidant requirements of endurance athletes: Implications for health

This review discusses studies investigating the effects of antioxidant supplementation on exercise-induced oxidative stress with a focus on the health implications. The aim is to determine antioxidant requirements for endurance athletes. Overall, differences in methodology make it difficult to compare the relatively small number of published studies on this topic. The types of studies needed to more adequately assess the health effects of antioxidant supplements in athletes (long-term interventions with hard end points) have not been done. Therefore, there is currently insufficient evidence to recommend antioxidant supplements for endurance athletes.

Cardiac syndrome X: relevance of arterial pressure waveform analysis to patients with chest pain and normal coronary arteries

We report the case study of a 68-year-old female with cardiac syndrome X presenting with abnormal pressure waveforms and a hypertensive response to exercise with ST-segment depression. After amlodipine treatment, pressure waveform morphology was significantly improved, exercise testing was normal and symptoms had resolved. This case emphasizes the potential clinical value of arterial waveform analysis.

Factors influencing Hong Kong Chinese patients' decision-making in seeking early treatment for acute myocardial infarction

The purpose of this study was to identify, through in-depth interview, factors that influenced 27 Hong Kong Chinese patients' decision-making in seeking early treatment for acute myocardial infarction (AMI). The median delay time from the onset of symptoms to arrival at the hospital was 15.6 hours for men and 53.7 hours for women. Three major categories emerged from the data: (a) becoming aware of the threat, (b) maintaining a sense of normality, and (c) struggling to mobilize resources. A variety of decisions were made by patients from the onset of chest Pain to seeking help. These decisions were heavily influenced by healthcare factors (access to emergency medical service (EMS) and treatment), personal factors (cognitive interpretations of symptoms), sociocultural factors (family situation, cultural beliefs, and practices), and coping strategies. (c) 2006 Wiley Periodicals, Inc.