It has been suggested that gender differences in running should disappear as distances increase, particularly past the marathon. This suggestion is primarily based on differences in fuel utilization, muscle damage following exercise, relative improvements in performance over the past decades, and on the analysis of marathon vs. ultramarathon performances of men and women. We reasoned that the best comparison of the potential of a human is by the use of world best times, which should be reasonable indicators of the effect of distance on relative performance of women and men. We compared current world best running performances at distances from 100 m to 200 km. Records as of December 2002 were obtained. T-tests analyzed speed differences between genders, and regression analysis tested the percent differences between men and women across distance. Speeds were different, with the average difference being 12.4% faster for men. There was a significant slope to the speed difference across distances in that longer distances were associated with greater differences. These results may be confounded by the reduced number of women in longer distance events. Furthermore, the proposed metabolic advantage for women because of increased fat metabolism may be masked by regular feeding during endurance races.

In evaluating the efficiency of humans performing exercise, base-line subtractions have been used in an attempt to determine the efficiency of the muscles in performing the external work. Despite the fact that base lines have been criticized previously, they have been widely used without adequate analysis of the implications involved. Calculations of efficiencies using data available in the literature for isolated muscle preparations revealed that base-line subtractions result in unreasonably high efficiencies. This suggests strongly that the base lines are invalid. To be valid, a base line must continue unchanged under all the conditions in which it is applied. Previously published data indicate clearly that exercise base lines change with increasing work rate and are therefore invalid. The use of base lines is further complicated by elastic energy storage in some types of exercise. Although exercise efficiencies using base line subtractions may be useful, they do not indicate muscle efficiency. Perhaps future studies of exercise metabolism should be directed less at refining base lines and more toward describing and quantifying the determinants of energy expenditure.

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The present study compared the responses of women with headache (chronic tension-type, n = 27; migraine, n = 27) and controls (n = 27) to an acute pain laboratory task, the cold pressor test. Participants' pain perception (i.e., threshold and tolerance) and their fear/anxiety associated with pain were assessed during days 1, 2, or 3 of menses. Analyses pertaining to participants' responses to the cold pressor test (ie, pain threshold and tolerance) failed to show statistically significant group differences, even when covarying pain-related anxiety/fear. Analyses did, however, reveal significant group differences between migraineurs and controls in cognitive anxiety. Correlational analyses also revealed that cognitive anxiety, somatic anxiety, fear, and escape/avoidance were all significantly correlated with pain tolerance in the group with chronic tension-type headache, but not in the other two groups. Subsequent multiple regressions, however, showed that the relationship between anxiety and pain tolerance was primarily a function of somatic anxiety. These results suggest that headache frequency plays a role in mediating the relationship between fear of pain and pain tolerance and that the models by Lethem and colleagues and McCracken may be relevant for understanding tension headache sufferers' responses to head pain.

The purpose of this study was 1) to compare the maximal oxygen uptake (VO2max) obtained in swimmers during tethered swimming, free swimming, and flume swimming, and 2) to determine whether an arm-ergometer test would provide comparable results. In the first experiments the VO2max for tethered swimming (2.67 +/- 0.26 l/min) and flume swimming (2.62 +/- 0.26 l/min) were not different (P greater than 0.05) and were highly correlated (r = 0.99). However, with arm ergometry a significantly lower VO2max (2.36 +/- 0.24 l/min) occurred from those found in the two swimming tests (P less than 0.05). Other experiments demonstrated that the tethered swimming VO2max (3.53 +/- 0.27 l/min) and the free swimming VO2max (3.55 +/- 0.28 l/min) also provide results that were similar (P greater than 0.05) and highly correlated with each other (r = 0.99). Differences between tethered and flume swimming, and tethered and free swimming were small, being 1.2 +/- 1.6% and 0.6 +/- 0.9%, respectively. Differences between tethered swimming and arm ergometry VO2max were large, 14.7 +/- 2.4%, despite the high correlation (r = 0.97) between these measurements. Predictions of a swimming VO2max from the arm-ergometer data yielded a considerable error (+/-7.1% and +/-7.4%). The present results indicate that flume swimming, free swimming, and tethered swimming yield essentially identical VO2max results.