The running economy of seventeen athletes was studied during running at a low speed (3.3 m X s-1) on a motor-driven treadmill. The net energetic cost during running expressed in kJ X kg-1 X km-1 was on average 4.06. As expected, a positive relationship was found between the energetic cost and the percentage of fast twitch fibres (r = 0.60, n = 17, p less than 0.01). In addition, the mechanical efficiency during two different series of jumps performed with and without prestretch was measured in thirteen subjects. The effect of prestretch on muscle economy was represented by the ratio between the efficiency of muscular work performed during prestretch jumps and the corresponding value calculated in no prestretch conditions. This ratio demonstrated a statistically significant relationship with energy expenditure during running (r = -0.66, n = 13, P less than 0.01), suggesting that the elastic behaviour of leg extensor muscles is similar in running and jumping if the speeds of muscular contraction during eccentric and concentric work are of similar magnitudes.

E Ef ff fi ic ca ac cy y o of f a a t th hr re ee e d da ay y c co ou ur rs se e o of f a az zi it th hr ro om my yc ci in n i in n m mo od de er ra at te el ly y s se ev ve er re e c co om mm mu un ni it ty y--a ac cq qu ui ir re ed d p pn ne eu um mo on ni ia a The aetiology of pneumonia was identified in 18 patients by serology (nine Mycoplasma pneumoniae, four Chlamydia pneumoniae, five Legionella pneumophila; one patient with chlamydial infection also had Klebsiella pneumoniae bacteraemia). A presumptive aetiological diagnosis was obtained with sputum culture in three other patients (one Haemophilus influenzae, two Haemophilus parainfluenzae), all strains were sole isolates with 10 8 Colony forming units (CFU), and with Gram stain in one patient with Streptococcus pneumoniae. All patients in the azithromycin group (one after a second 3 day course), and all but two (of those available for evaluation) of the clarithromycin group were cured. Defervescence occurred after 2.6±1.6 days, and chest roentgenogram cleared after 8.9±3.3 days, with no difference between the two groups. Tolerance was good, and there were no withdrawals from therapy.Azithromycin, as well as clarithromycin, may be a good first choice approach for the treatment of low to moderately severe community-acquired pneumonia, but a 3 day course of azithromycin may increase patient compliance.

The mechanical efficiency of positive work was studied in six subjects performing three different types of exercises. On the first occasion the subjects ran on a motor-driven treadmill at 3.33 m s-1; the second and the third exercises consisted of performing rhythmical vertical jumps for 1 min both in rebound (RJ) and no-rebound (NRJ) conditions. The mechanical efficiency calculated in NRJ, which reflects only the conversion of biochemical energy into mechanical work, was found to be lower than the corresponding observation in RJ, 17.2 vs. 27.8% (P less than 0.001), respectively. These differences could not be explained by only the storage and recoil of elastic energy occurring in RJ compared with NRJ. The calculated extra work delivered 'free' was greater than the potential elastic energy which could be stored within the leg extensor muscles (187 vs. 124 J for each jump, P less than 0.05). It is likely that other factors might be responsible for the extra work found in NRJ. It was suggested that the difference in the length of time to perform positive work between a simple shortening contraction and a stretch-shortening muscular activity could be also responsible for the enhanced efficiency observed in RJ. This suggestion was supported by the high relationship (P less than 0.001) found between the time to perform positive work and the mechanical efficiency measured in jumping and estimated during running.

We are describing a case of a female infant with ventriculoperitoneal shunt scheduled for inguinal hernia repair under spinal anesthesia. The child was a premature newborn who, in a recent past, underwent surgery in general anesthesia for retinopathy correction with subsequent difficult mechanical ventilation weaning. The benefit of spinal anesthesia in high-risk infant was described and the risks of spinal anesthesia in the presence of a ventricular shunt device-especially dural leakage and infections were briefly discussed.