A theoretical analysis was used to evaluate the effect of body mass on the mechanical power cost of cross-country skiing and roller skiing on flat terrain. The relationships between body mass and the power cost of overcoming friction were found to be different between cross-country skiing on snow and roller skiing. Nevertheless, it was predicted that the heavier skier should have a lower oxygen cost per unit of body mass for roller skiing, as is the case for snow skiing. To determine whether the theoretical analysis was supported by experimental data, oxygen consumption measurements were performed during roller skiing by six male cross-country ski racers who spanned a 17.3-kg range in body mass. The theoretical analysis was supported by the experimental findings of decreases in oxygen consumption for each kg increase in body mass of approximately 1.0% for the double pole technique, 1.8% for the kick double pole technique, and 0.6% for the VI skate technique.

The aim of the present study was to assess the influence of hyperbaric oxygenation (HBO) on rat liver regeneration before and after partial hepatectomy. Rats were sacrificed 54 h after 15% hepatectomy, liver and body weights were measured, and serum alanine transaminase (ALT) and aspartate transaminase (AST) activity and albumin levels were determined. The lipid peroxide level, as indicated by malondialdehyde production in the remnant liver was measured, and liver sections were analyzed by light microscopy. Five groups of 10 rats in each group were studied. The preHBO and pre-hyperbaric pressure (preHB) groups were treated before partial hepatectomy with 100% O 2 and 21% O 2 , respectively, at 202,650 pascals, daily for 3 days (45 min/ day). The control group was not treated before partial hepatectomy and recovered under normal ambient conditions after the procedure. Groups postHBO and postHB were treated after partial hepatectomy with HBO and HB, respectively, three times (45 min/day). The preHBO group presented a significant increase in the initiation of the regeneration process of the liver 54 h postoperatively. The liver/body weight ratio was 0.0618 ± 0.0084 in the preHBO compared to 0.0517 ± 0016 g/g in the control animals (P = 0.016). In addition, the preHBO group showed significant better liver function (evaluated by the lowest serum ALT and AST activities, P = 0.002 and P = 0.008, respectively) and showed a significant decrease in serum albumin levels compared to control (P < 0.001). Liver lipid peroxide concentration was lowest in the preHBO group (P < 0.001 vs control and postHBO group) and light microscopy revealed that the composition of liver lobules in the preHBO group was the closest to normal histological features. These results suggest that HBO pretreatment was beneficial for rat liver regeneration after partial hepatectomy.

This study evaluated the physiological responses to roller skiing with three different techniques, and compared the physiological responses during roller skiing with a standard pole grip and an innovative "anatomical" pole grip. Data were collected on ten experienced crosscountry ski racers while roller skiing with the double pole, VI skate, and kick double pole techniques on a flat track at mean (±SD) velocities of 14.6±0.2, 16.4±0.3, and 18.0±0.4 kmh 1 The kick double pole technique induced the highest (p < 0.05) oxygen uptakes, heart rates, and ventilations. The double pole technique elicited the lowest (p <0.05) oxygen uptakes, and the VI skate technique elicited the lowest (p < 0.05) perceived effort and respiratory exchange ratios. Comparison of the two pole grips showed no differences in the physiological responses and perceived effort. While the VI skate technique is not the most economical roller skiing technique on flat ground, the lower associated perceived effort and respiratory exchange ratios may at least partially account for the general preference of cross-country ski racers to use the VI skating technique rather than the double pole technique on flat terrain.

The use of in-line skates has become popular in recent years for recreational and conditioning purposes. This investigation evaluated the physiological responses of ten subjects during in-line skating on a flat track with three different in-line skating techniques. The double pole technique demonstrated the greatest economy with oxygen uptake requirements that were approximately 12% lower (p less than 0.05) than conventional skating (without poles) or the V1 skate technique. Across the investigated velocity spectrum of 14.6 to 18.0 km.h-1, individuals with an average fitness level of 40 ml.kg-1.min-1 will achieve exercise intensities of 68-90% of maximum oxygen uptake using the conventional skating and V1 skate techniques on flat terrain. These exercise intensities are appropriate for cardiorespiratory training. However, high fit individuals who are attempting to elicit a cardiorespiratory training effect using in-line skates with rolling resistances similar to those tested may need to perform uphill interval work or skate at higher velocities which may be technically difficult and may be unsafe in some training environments. Comparison of the present data with previously published data on roller skiing demonstrates that differences in physiological responses for the two modes of exercise are the result of differences in rolling resistances between the devices. Measurements of rolling resistance and comparison of the oxygen uptake requirements for double polling on both devices allow for the mechanical efficiency to be estimated at approximately 18% for this mode of locomotion.

Pigeon serum (PS) is one of the most common causes of hypersensitivity pneumonitis (HP). PS-induced HP was examined in a dog model. The dogs (n = 6) were immunized by i.m. injections of PS, followed by insufflation with aerosolized PS, while all control dogs (n = 3) received saline only. All animals insufflated with PS developed tachypnea 2-4 h after PS inhalation. After PS insufflation, a significant decrease in arterial oxygen tension (PaO2) was detected in sensitized dogs. No change in PaO2 was detected in sensitized dogs after saline or in the controls after PS insufflation. In intradermal skin tests with PS antigen, a positive skin reaction was found in 3/6 dogs in 30 min, and in 5/6 dogs in 6 and 48 h after the PS injections. Sensitized dogs showed a significant increase in PS-specific IgG in serum and lavage fluid (LF). In LF of sensitized dogs, an increase in the percentage of lymphocytes, eosinophils, and neutrophils was detected. Sensitized dogs developed chronic interstitial inflammation with lymphocytes, macrophages, plasma cells, and eosinophils in lungs. Granulomas with lymphocytes, histiocytes, and giant cells were detected in both the interstitium and the bronchiolar wall in the lungs of sensitized dogs. PaO2 was lowest in dogs showing the most severe interstitial inflammation in the lungs. The results indicate that dogs can be successfully used in immunologic and physiologic studies of PS-induced HP.