Increased dietary carbohydrate and endurance during single-leg cycling using a limb with normal muscle glycogen concentration

The purpose of this study was to test the hypothesis that increased availability of blood-borne glucose would improve endurance after carbohydrate loading. A single-leg exercise model was employed, taking advantage of the fact that supercompensation of muscle glycogen occurs only in a previously exercised limb. Endurance time to exhaustion at 70% of maximal oxygen uptake (VO2 max) was determined for 11 males and three females who were then allocated to a control group or a high-carbohydrate (CHO) group. For 3 days following Test 1 the control group maintained a prescribed normal diet whilst the CHO group increased the proportion of energy derived from carbohydrate (62.1 +/- 4.3% cf. 43.9 +/- 2.0%, P less than 0.01). The endurance test was then repeated using the leg that was inactive during Test 1. Endurance time was increased on Test 2 (123.7 +/- 43.2 min cf. 98.5 +/- 21.9 min, P less than 0.05 one-tailed test) for the CHO group but not for the control group (101.8 +/- 21.7 min cf. 107.5 +/- 9.1 min, NS). There was no indication of enhanced carbohydrate metabolism during Test 2 for the CHO group but mean heart rate was lower during Test 2 than during Test 1 (145 +/- 14 beat min-1 cf. 152 +/- 12 beat min-1, P less than 0.05). These results suggest that the prior consumption of a high-carbohydrate diet improves endurance during high-intensity cycling with a limb with normal muscle glycogen concentration.     

An analysis of the PPCF as a theoretical framework for an instrument to examine teacher priorities for selecting curriculum content

The purpose of the research was to develop an instrument to examine physical education teachers' priorities for curricular decision-making. The purpose dimension of the Purpose Process Curriculum Framework (PPCF) was used as the theoretical structure for content decisions. Three studies are reported that investigate the reliability and validity of the proposed instrument. Items were evaluated for relevance and validity of the proposed instrument. They were evaluated for relevance and theoretical consistency by physical education teachers (Study 1) and curriculum specialists (Study 2). Acceptable items were then placed in a ranking format and field tested with physical educators in three school districts (Study 3). Results from Study 1 indicated that secondary level physical education teachers supported the relevance of items to reflect the educational setting in their classes. In Study 2, mean ratings of curriculum specialists established that 19 of the 22 categories were theoretically consistent with the PPCF. However, internal consistency coefficients (alpha) for 10 of the 22 purposes were less than .70. Follow-up field tests with physical educators in Study 3 indicated that only one category, joy of movement, had a coefficient above .70. In this research internal consistency coefficients were too low to make a claim for the reliability of the concept scales of the instrument. The multidimensionality of the purpose concepts raised questions regarding the validity of the PPCF and prohibited the use of the framework as a theoretical basis for instrument development.