European journal of applied physiology and occupational physiology
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Eur J Appl Physiol Occup Physiol · Jan 1998
Randomized Controlled Trial Clinical TrialPositive end expiratory pressure as a method for preventing acute mountain sickness.
In order to study the use of positive end expiratory pressure (PEEP) to prevent acute mountain sickness (AMS), 22 subjects were exposed randomly to 8-h hypobaric hypoxia in a hypobaric chamber (4500 m, 589 hPa, 22 degrees C) once being administered 5-cm H2O PEEP and once without. The prevention of AMS by PEEP was evaluated by scoring AMS according to the Lake Louise system (self-report questionnaire and clinical assessment) throughout the experiment with O2 saturation (SO2) and heart rate measurements being made. Arterial blood analyses (partial pressures of arterial O2 and CO2, PaO2, PaCO2, and pH) were made at the end of the exposure. ⋯ Moreover, heart rate increased with PEEP (P < 0.05). In conclusion, this study would suggest that a 5-cm H2O PEEP may help decrease AMS scores at the end of an 8-h exposure to hypoxia in a hypobaric chamber. Such a method could be used to prevent AMS in such experimental conditions without adverse effects.
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Eur J Appl Physiol Occup Physiol · Jan 1998
Back extensor and psoas muscle cross-sectional area, prior physical training, and trunk muscle strength--a longitudinal study in adolescent girls.
The association between physical training, low back extensor (erector spinae plus multifidus muscles) and psoas muscle cross-sectional areas (CSA) and strength characteristics of trunk extension and flexion were studied in adolescent girls. A group of athletes (n = 49) (age range 13.7-16.3 years) consisting of gymnasts, figure skaters and ballet dancers was age-matched with non-athletes (n = 17) who acted as a sedentary control group. The CSA of psoas muscles and multifidus plus erector spinae muscles were measured from lumbar axial images by magnetic resonance imaging. ⋯ There was a significant correlation between muscle CSA and strength parameters, but the force per muscle CSA did not differ significantly between the athletes and the non-athletes. In addition, the athletes showed a better body mass adjusted muscle endurance in trunk flexion (P < 0.05) than the non-athletes. Our study indicated that regular physical training enhances trunk musculature hypertrophy, force and endurance in adolescent girls, and that there is an association between muscle CSA and strength parameters.