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Objectives: A matched case-control study was carried out to evaluate biological risk indicators for recurrent non-specific low back pain in adolescents. Methods: Adolescents with recurrent non-specific low back pain (symptomatic; n = 28; mean (SD) age 14.9 (0.7) years) and matched controls (asymptomatic; n = 28; age 14.9 (0.7) years) with no history of non-specific low back pain participated. Measures of stature, mass, sifting height, sexual maturity (Tanner self assessment), lateral flexion of the spine, lumbar sagiltal plane mobility (modified Schober), hip range of motion (Leighton flexometer), back and hamstring flexibility (sit and reach), and trunk muscle endurance (number of sit ups) were performed using standardised procedures with established reliability. Backward stepwise logistic regression analysis was performed, with the presence/absence of recurrent low back pain as the dependent variable and the biological measures as the independent variables. Results: Hip range of motion, trunk muscle endurance, lumbar sagittal plane mobility, and lateral flexion of the spine were identified as significant risk indicators of recurrent low back pain (p < 0.05). Follow up analysis indicated that symptomatic subjects had significantly reduced lateral flexion of the spine, lumbar sagittal plane mobility, and trunk muscle endurance (p < 0.05). Conclusions: Hip range of motion, abdominal muscle endurance, lumbar flexibility, and lateral flexion of the spine were risk indicators for recurrent non-specific low back pain in a group of adolescents. These risk indicators identify the potential for exercise as a primary or secondary prevention method. [ABSTRACT FROM AUTHOR]

Objective: To examine the effects of oral contraceptive use on maximum force production in young women. Methods: In the study, 21 female subjects (14 pill users and seven eumenorrheic controls) took port. All pill using subjects had been taking o combined, monophasic oral contraceptive pill for at least 6 months. Maximum dynamic and isometric leg strength, maximum isometric strength of the first dorsal interosseus (FDI) muscle, and plasma concentrations of oestradiol and progesterone were measured on days 7 and 14 of pill consumption and day 5 of pill withdrawal. The eumenorrheic group was tested (FDI strength and hormone concentrations) on days 2 and 21 of the menstrual cycle. Results: There were no significant changes in the concentration of endogenous oestradiol or progesterone or any measure of muscle strength between pill phases (p < 0.05). The pill group did not significantly differ from the eumenorrheic group (p < 0.05), despite a significant increase in the concentration of progesterone and oestradiol on day 21 of the menstrual cycle compared with day 2 of the menstrual cycle and pill consumption and withdrawal (p < 0.05). Conclusions: These data suggest that oral contraceptive use does not significantly affect muscle strength. Moreover, oral contraceptive users were not stronger or weaker than their eumenorrheic counterparts. [ABSTRACT FROM AUTHOR]

Hypothermia has long been recognized as a most serious condition, often with fatal consequences for hill walkers, fell runners, and high altitude mountain climbers. However, research into hypothermia occurring in the mountainous environment has, at best, been limited. The physiology and mechanisms of hypothermia in mountainous areas are discussed in this article. The best off-set for hypothermia is to maintain heat production by means of exercise, and so fatigue becomes a critical predisposing factor. It is as important to facilitate heat loss, especially during periods of high exertion, as it is to maintain heat production and preserve insulation.

Up until now, the exact mechanism by which neuromodulation using sacral nerve stimulation works still remains unknown. Recent studies of pelvic floor contraction during peripheral nerve evaluation (PNE) have shown that several muscle responses are reflexly mediated. However, whether these reflexes originate from a segmental level within the sacral spinal cord or from supraspinal neuronal centers involving spino-bulbospinal pathways remains to be determined. Therefore, recordings of external anal sphincter reflexes during PNE in complete spinal cord injury (SCI) patients was performed. Three patients with complete SCI (two female and one male) suffering from neurogenic incontinence underwent the first stage of a stimulator implant (peripheral nerve evaluation). Stimulation was obtained through an electrode placed in the S3 foramen. Concomitantly, the latency of the response of the striated anal sphincter was measured using a concentric needle electrode placed in the striated part of the anal sphincter. Repeated measurements within an interval of 30 min were performed to confirm the reliability of the responses. In all subjects, reflex responses of early and late latencies could be recorded. The early response showed a mean latency of 41.2 ms (range 33.3–62 ms), which corresponds to a segmental reflex, similar to the pudendo-anal reflex. The late response appeared with a mean latency of 189.4 ms (range: 183.3–197.8 ms) and with high variability and fatigability, suggesting a reflex response organized at polysegmental spinal levels. Despite successful foramina lead placement, none of our complete SCI patients showed any improvement of neurogenic incontinence after 5 days of treatment by sacral nerve stimulation. The findings confirm that the anal contractions observed during peripheral nerve evaluation are reflex responses mediated by afferent pathways. Both the early and late reflex responses are of spinal origin, since they were obtained in complete SCI patients in whom all spino-bulbo spinal loops are supposed to be interrupted. The finding that neuromodulation is working in non-neurogenic patients but is less successful in complete SCI patients could give evidence that preserved spino-bulbo spinal loops contribute to the positive effects of neuromodulation. The role of an eventual spino-bulbo spinal loop acting during neuromodulation in non-neurogenic patients has to be assessed in further studies. [ABSTRACT FROM AUTHOR]