Beyond the mind-body exercise hype.

Mind-body exercise methods are spreading rapidly throughout the health, fitness, and rehabilitation fields. Many of the claimed benefits for these activities are not supported by clinical evidence, and, as alternative therapies, they carry legal and professional ramifications. Understanding the nature of mind-body exercise and knowing the scientific evidence behind claims for its benefits can help clinicians make appropriate recommendations to patients. For example, yoga and tai chi can reduce stress, decrease hypertension, and exert cardiorespiratory benefits, and tai chi can improve balance in seniors. However, there is not enough evidence to support replacing conventional medical treatments with somatic methods.

Neuromuscular control mechanisms and strategy in arm movements of attempted supranormal speed.

Rapid, goal-directed elbow flexion movements were examined under interacting conditions of inertial loading and resistance to movement initiation. The resistance ceased when movement began, resulting in quick release movements. Inertial load slowed the movement and lengthened the agonist and antagonist electromyographic (EMG) burst durations. The quick release resulted in larger accelerations but only minimal changes in peak velocity. Most aspects of the triphasic EMG pattern were little affected by the quick release, but the build up of agonist EMG and the corresponding rate of static force development differed markedly between load and quick release conditions. These and other data suggest that the specific pattern of agonist muscle activation is set according to neuromuscular constraints of the antagonist muscle and the expectation of movement dynamics.

The Feldenkrais Method® in rehabilitation: a review.

Musculoskeletal disorders are often suggested to be caused, in part, by poor postural behaviors that are associated with occupational demands. The inefficacy of conventional strategies to elicit postural correction has prompted many to seek alternative techniques such as the Feldenkrais Method®. The rapidly growing use of the Feldenkrais Method® by laypersons and professionals has been fueled by extravagant claims and data published in non-peer-reviewed sources, for the effectiveness of this technique has been poorly documented in peer-reviewed publications. Therefore the purpose of this review was to critically assess the literature on the Feldenkrais Method® in both juried and non-juried sources. The results have generally indicated some improvement with Feldenkrais® interventions, however, these improvements are not nearly as large as suggested by the anecdotal claims. Unfortunately, most of the juried and non-juried findings and conclusions are questionable due to inadequately controlled studies and other serious methodological problems. As such, determination of the effectiveness of the Feldenkrais Method® based on the literature is difficult at best, and the only justifiable conclusion is that more study is warranted.

Neuromuscular control following maximal eccentric exercise.

Kinematic and electromyographic (EMG) analysis of a target-directed, maximal velocity movement was used to investigate the effects of high-force eccentric exercise on the neuromuscular control of elbow flexion. Ten non-weight-trained females [19.6 (1.6) years old] performed 50 maximal velocity elbow flexion movements from 0 to 1.58 rad (90 degrees), as rapidly as possible in response to a light stimulus, while kinematic and triphasic EMG parameters were measured. This was done three times pre-exercise, immediately and 1, 2, 3, 4, and 5 days following the 50 maximal eccentric elbow flexion actions. The eccentric exercise caused lengthening of kinematic parameters including total movement time and time to peak velocity. The EMG elements of the biceps brachii (b.) motor time, time to peak EMG, biceps b. burst duration, and the latency period between biceps b. and triceps b. bursts were lengthened post-exercise. These changes persisted for up to 5 days post-exercise. The exercise also caused a large increase in serum creatine kinase (CK) activity. It was concluded that high-force eccentric exercise in this population caused prolonged changes in neuromuscular control that were a function of exercise-induced disruption of the skeletal muscle. Compensation in the central motor program was such that the components of the triphasic EMG pattern were systematically lengthened.

Rapid movement kinematic and electromyographic control characteristics in males and females.

Maximally fast, self-terminated elbow flexion movements were performed by 10 male and 10 female college-aged subjects to assess potential gender-related differences in kinematics and the triphasic electromyographic (EMG) pattern. The subjects were instructed to move their forearms as fast as possible through 90 degrees of elbow flexion range of motion and stop as sharply as possible at the terminal point. An electromagnet, set to 0, 40, and 70% of each subject's maximal isometric torque, provided resistance to movement initiation and resulted in quick release movements. Surface EMG was collected from the biceps b. and triceps b. muscles. Results indicated that the males had faster movements and accelerations under all conditions. EMG records indicated that the males had faster rates of EMG rise, particularly in the triceps b., and more tightly coupled reciprocal activation. The quick release afforded faster accelerations for both groups, yet only the males moved faster throughout the full range of motion. Following the quick release, the males differed from the females by increasing the triceps b. EMG amplitude. Hence, the males were able to shorten movement time in quick release movements by increasing triceps b. activation and, thus, braking ability. These results suggest that the females were more neurally constrained than the males with respect to rapid EMG activation of the triceps b., resulting in limits in the braking process.

Lung cancer mortality among women employed in high-risk industries and occupations in Harris County, Texas, 1977-1980.

Lung cancer is rapidly becoming the leading cause of cancer mortality among women. Interviews conducted with 259 women with lung cancer and 278 women without lung cancer or with their next-of-kin in Harris County, Texas from July 1, 1977 to June 30, 1980 revealed that 12 (4.6%) of the women with lung cancer had never smoked cigarettes. The odds ratio (OR) for current smoking was 15.7. Odds ratios for smoking for living women (OR = 17.5) were higher than for those who were deceased (OR = 12.6). Lifetime occupational histories were classified a priori into high- and low-risk categories. Data were stratified according to employment in a high-risk industry or occupation, a high-risk industry, a high-risk occupation, or both a high-risk industry and occupation. Although not statistically significant, odds ratios for employment in high-risk categories support earlier estimates that attributed 5% of lung cancer mortality in women to employment in hazardous occupations. Employment of a husband or household member in selected industries and occupations yielded significantly increased odds ratios. More cases (15.9%) than controls (6.9%) reported a family history of lung cancer (OR = 2.4). No significant increase in smoking-adjusted odds ratios was found for the use of hair spray, hand-held dryers, or alcohol, or for having lived with a household member who smoked cigarettes.

Environmental associations and histopathologic patterns of carcinoma of the lung: the challenge and dilemma in epidemiologic studies.

An update of histopathologic classification schemes is provided for carcinoma of the lung and factors that influence proportional distributions of cell types, i.e., sources and preparations of tissue specimens, observer variability, and use of secondary sources of information. Consideration is given to the natural history and to current knowledge of the demographic characteristics of cell types of carcinoma of the lung. A review of studies reporting histopathologic associations with environmental exposures suggests that no single type of carcinoma of the lung is specifically associated with exposure to tobacco smoke, arsenic, or beryllium. Furthermore, studies concerned with exposure to asbestos, chloroethers, chromates, nickel, vinyl chloride, and radioactivity lack sufficient information to conclude definitively that only one specific lung cancer cell type is associated with these exposures. In conclusion, an exclusive association of a single cell type of carcinoma of the lung with exposure to the physical or chemical agents reviewed has not been demonstrated.