Phosphate loading and the effects on VO2max in trained cyclists

It is known that an increased level of red blood cell 2,3-diphosphoglycerate (DPG) shifts the oxyhemoglobin dissociation curve to the right, thus allowing a greater unloading of oxygen at the tissue level. It has been hypothesized that phosphate might help increase VO2max by increasing 2,3-DPG level. Eight trained cyclists underwent three cycle ergometer tests (control, placebo, and experimental) to determine whether phosphate ingestion had any positive effect on VO2max, time to exhaustion, serum 2,3-DPG, and serum phosphate levels. We found no change between the control, placebo, or experimental conditions in pretest serum phosphate levels, but we did find increases in 2,3-DPG levels in the phosphate condition (p less than .05), which suggests that even a small amount of phosphate could increase levels of 2,3-DPG. We also found significant differences in VO2max between the control (p less than .05) and placebo (p less than .02) conditions and also in time to exhaustion between the three conditions (p less than .05). We suggest that phosphate may have an ergogenic effect, but clearly more work needs to be undertaken to ascertain the amount of phosphate required and the magnitude of the effect.     

The role of stimulus salience in young children's ability to discriminate two-dimensional rotations: Reflections on a paradigm

Children's ability to discriminate reflections and rotations of visual stimuli was examined within the confines of a mental rotation task. It was hypothesized that success would be affected by both characteristics of the stimulus and by the subtlety of the discrimination required. Forty 3- to 4-year-old children were directed to mentally rotate a stimulus a given number of degrees and to discriminate the appearance of the rotated stimulus from among a set of alternatives. Four stimuli differing in the number of visual orientation cues were utilized across 24 trials. A significant effect was found for number of orientation cues, and data indicated the difficulty children experienced detecting reflections, a task which bears close resemblance to the yes/no option in prototypic rotation studies. Children were only successful with a limited range of stimuli when discrimination of a reflected foil was not required. Results are discussed in light of discrepant findings about children's kinetic imagery ability and the advisability of using this particular paradigm with young Children.