Faculty Bibliography

STUDY DESIGN: This was a repeated measures study examining 11 asymptomatic subjects while performing dynamic lifting using various postures, loads, and breath control methods. OBJECTIVES: To examine the effects of breath control on magnitude and timing of intra-abdominal pressure during dynamic lifting. SUMMARY OF BACKGROUND DATA: Intra-abdominal pressure has been shown to increase consistently during static and dynamic lifting tasks. The relationship between breath control and intra-abdominal pressure during lifting is not clear. METHODS: Eleven healthy subjects were tested using lifting trials consisting of two levels of posture and load and four levels of breath control (natural breathing, inhalation-hold, exhalation-hold, inhalation-exhalation). Intra-abdominal pressure was measured using a microtip pressure transducer placed within the stomach through the nose. Timing of intra-abdominal pressure was determined relative to lift-off of the weights. Repeated measures analysis of variance was used to determine the effect of breath control, posture, and load on intra-abdominal pressure magnitude and timing. RESULTS: There was a significant effect of breath control (P < 0.018) and load (P < 0.002), but not of posture (P < 0.434), on intra-abdominal pressure magnitude. The inhalation-hold form of breath control produced significantly greater peak intra-abdominal pressure than all other forms of breath control (P < 0.000 for all comparisons). No other comparisons among levels of breath were significantly different. No significant main effects of breath control were found relative to intra-abdominal pressure timing. CONCLUSIONS: Breath control is a significant factor in the generation of intra-abdominal pressure magnitude during lifting tasks. The effects of respiration should be controlled in studies analyzing intra-abdominal pressure during lifting

Work in construction is associated with a high risk for musculoskeletal disorders and injuries. The symptom survey was conducted to determine the magnitude and musculoskeletal injury characteristics among the cement and concrete workers and identify the most problematic work-related activities and job factors that might have contributed to the occurrence of these disorders. Findings revealed that a large proportion of the laborers (77%) experienced at least one musculoskeletal disorder in the last year. Low back pain was reported as the most frequently experienced symptom (66%). 'Working while in pain' the concrete workers perceived as the major problem in the trade. Other problematic work-related activities included 'bending or twisting the back', 'work in hot, cold or wet conditions', and 'handling heavy objects'. Most of the laborers (82%) requested on-the-job safety training. Survey results combined with the outcomes of focus groups discussions and work site observations were used in the design of a training program aimed at the prevention of musculoskeletal morbidity in the trade. The program incorporated ergonomics principles, hazard recognition, safe work practices, problem solving and personal protection in the training curriculum for membership of the trade

STUDY DESIGN: Retrospective cohort study was conducted. OBJECTIVE: To evaluate the association of prescribed work restrictions with work absenteeism and recurrence in cases of nonspecific low back pain. SUMMARY OF BACKGROUND DATA: The efficacy of commonly prescribed work restrictions in limiting sickness-related absence because of back pain has not been evaluated. METHODS: Employees who had back pain-related sickness absence were identified from medical records of a utility company. The workers were grouped into those who had received a work restriction for their back pain and those who had not. The duration of work disability was compared between the two groups. Employees who returned back to regular, full duty within 1 year of onset were followed for one additional year to determine rates of recurrence. The Cox Proportional Hazards model was used to generate hazard ratios adjusted for age, gender, and job category. RESULTS: Restrictions were given to 43% of the workers. Sickness absence duration did not differ between those who had received restrictions and those who had not (adjusted hazard ratio, 1.12; P = 0.41). The median duration of restricted duty was 32.5 days. For 22% of the workers, restricted duty was never lifted. Recurrence appeared less likely to occur among those who had work restrictions in their initial episode. However, this difference was not statistically significant (adjusted hazard ratio, 0.77; P = 0.48). CONCLUSIONS: No evidence of an association between a prescription of work restriction and early return to work was found. More research is needed to clarify the utility of restricted duty in promoting a positive outcome for work-related low back pain

Low back pain represents a serious public health problem. Therefore, great efforts have been made in order to improve and assess the efficacy of its treatment. Reports in international literature have presented important studies concerning instruments to assess pain and functional incapacity in patients with low back pain. This study presents a clinical protocol which was developed by a multidisciplinary team. This protocol consists of the evaluation and distribution of pain, The Spitzer Quality of Life, The Oswestry Low Back Pain Disability Questionnaire, and The Center for Epidemiological Studies Depression Scale. Instruments must be urgently developed or adapted in order to be used according to the Brazilian reality

AIM: Surprising sensory stimuli causing arousal are known to evoke short-lasting activation of human sympathetic activity in skin but not in muscle nerves. In fact, anecdotal observations suggest that muscle sympathetic activity may be inhibited. To test this hypothesis, the effects of surprising somatosensory (electrical skin pulses) or visual (flash) stimuli on multiunit muscle sympathetic activity were studied in 36 healthy subjects, aged 19-71 years. METHODS: The stimuli were given either 200 or 400 ms after the R-wave of the electrocardiogram. Dummy stimuli, consisting of trigger pulses without sensory stimuli, served as controls. RESULTS: On a group basis, a single sensory stimulus of either type attenuated the amplitude of one or two sympathetic bursts, while no such effects occurred after dummy stimuli. Individually, the inhibition was evoked by at least one stimulus modality or delay in 16 subjects, whereas in three subjects no significant inhibition occurred. Electrodermal signs of skin sympathetic activation were present in all subjects. Compared with one, five repeated electrical skin pulses induced only minor additional inhibition of muscle sympathetic activity, indicating marked habituation of the neural response. In nine subjects, the experiments were repeated once and in three subjects twice (with intervals of 2-3 months); in 11 of the 12 subjects, the sympathetic effects were reproducible. In the group of subjects without significant sympathetic inhibition the stimuli induced a small, transient increase of mean blood pressure, which was not present in the group with sympathetic inhibition. CONCLUSION: The finding that different sensory stimuli induce similar effects that habituate markedly on repetition suggests that the inhibition of muscle sympathetic activity is because of arousal. The interindividual differences in sympathetic and blood pressure effects may be part of interindividual differences in behavioural responses to stress