Previous researchers have suggested that faster marathoners tend to run at a more consistent pace compared with slower runners. None has examined the influence of sex and age on pacing. Therefore, the purpose of this study was to determine the simultaneous influences of age, sex, and run time on marathon pacing. Pacing was defined as the mean velocity of the last 9.7 km divided by that of the first 32.5 km (closer to 1.0 indicates better pacing). Subjects were 186 men and 133 women marathoners from the 2005, 2006, and 2007 races of a midwestern U.S. marathon. The course was a 1.6 km (1 mile) loop with pace markers throughout, thus facilitating pacing strategy. Each 1.6-km split time was measured electronically by way of shoe chip. The ambient temperature (never above 5°C) ensured that hyperthermia, a condition known to substantially slow marathon times and affect pacing, was not likely a factor. Multiple regression analysis indicated that age, sex, and run time (p < 0.01 for each) were simultaneously independent determinants of pacing. The lack of any 2- or 3-way interactions (p > 0.05 for each) suggests that the effects of 1 independent variable is not dependent upon the levels of others. We conclude that older, women, and faster are better pacers than younger, men, and slower marathoners, respectively. Coaches can use these findings to overcome such tendencies and increase the odds of more optimal pacing.

Recent research suggests that women tend to exhibit less of a precipitous decline in run velocity during the latter stages of a marathon than men when the covariates of age and run time are controlled for. The purpose of this study was to examine this sex effect with the added covariate of heat stress on pacing, defined as the mean velocity of the last 12.2 km divided by the mean velocity of the first 30 km. A secondary purpose of this investigation was to compare the pacing profiles of the elite men and women runners and the pacing profiles of the elite and nonelite runners. Subjects included 22,990 men and 13,233 women runners from the 2007 and 2009 Chicago marathons for which the mean ambient temperatures were 26.67° C and 2.77° C, respectively. Each 5-km split time was measured via an electronic chip worn on the participants' shoe. Multiple regression analysis indicated that age, sex, heat stress, and overall finish time (p < 0.01 for each) were simultaneous independent elements of pacing. Nonelite women were consistently better pacers than nonelite men in both marathons, and this sex difference was magnified from cold to warm race temperatures. No difference (p < 0.05) in pacing was found between elite men and women runners. Elite men and women had enhanced pacing over their nonelite counterparts. In hotter temperatures, coaches of novice runners should advise their athletes to implement a slower initial velocity to maintain or increase running velocity later in the race.

No abstract

This study examined the bivariate relationship between peak oxygen uptake (V(O2) peak); l/min) and body size in adult men (n = 1,314, age 17-66 yr), using both "simple" and "full" iterative nonlinear allometric models. The simple model was described by V(O2) peak = M(b) (or FFM(b)) exp(c SR-PA) exp(a + d age) epsilon (where M is body mass in kg; FFM is fat-free mass in kg; SR-PA is self-reported physical activity; epsilon is a multiplicative error term; and exp indicates natural antilogarithms). The full model was described by V(O2) peak = M(b) (or FFM(b)) exp(c SR-PA) exp(a + d age) + e (epsilon), where e is a permitted Y-intercept term. The M exponent obtained from simple allometry was 0.65 [95% confidence interval (CI), 0.59-0.71], suggestive of a curvilinear relationship constrained to pass through the origin. This "zero Y-intercept" assumption was examined via the full allometric model, which revealed an M exponent of 1.00 (95% CI, 0.7-1.31), together with a positive Y-intercept term (e) of 1.13 (95% CI, 0.54-1.73). The FFM exponents were not significantly different from unity in either the simple or full allometric models. It appears that the curvilinearity of the simple allometric model (using total M) is fictitious and is due to the inappropriate forcing of the regression line through the origin. Utilizing FFM as the body-size variable revealed a linear relationship between body size and V(O2) peak, irrespective of model choice. We conclude that the population mass exponent for V(O2) peak is close to unity.

VO2max expressed in ml.BM-1.min-1 (BM = body mass) has been shown to unduly penalize heavier subjects and instead should be expressed as ml.BM-0.7.min-1. Such findings support the "theory of similarity" (TofS) that proposes the BM exponent should be 2/3 (0.67). The TofS, however, applies better to lean body mass (LBM) that is uninfluenced by fat mass. For young adults, the actual scaling exponent of LBM has yet to be satisfactorily determined. We used allometric scaling (AS) to scale VO2max by BM and LBM in 94 women (age = 27.4 +/- 6.7 yr, BM = 60.3 +/- 8.4 kg). Treadmill VO2max was assessed by indirect calorimetry and LBM was determined from hydrostatic weighing. AS yielded the following exponents (+/- 95% C.I.): BM: 0.61 +/- 0.27, and LBM: 1.04 +/- 0.26. We conclude that VO2max in ml.BM-1.min-1 indeed penalizes heavier women, but this penalty applies only to those who are heavier because of larger percent body fat, not LBM. If one takes the position that excess fatness is undesirable, then from a health and performance perspective, expressing VO2max in ml.BM-1.min-1 may provide an unbiased and useful expression of VO2max in young women.

Although not statistically significant, peak torque values for both quadriceps and hamstring muscles were consistently higher after 30 seconds of WBV at 26 vs 2 Hz. Whether WBV presents a viable treatment option as either a warm-up activity or a long-term exercise intervention is yet to be determined. Future studies should include a wider variety of WBV parameters and the use of functional outcome measures.

This study was designed to examine the ability an endurance exercise training program to alter blood levels of cholesterol, HDL-cholesterol, LDL-cholesterol, and triglycerides in children. Thirty-one sixth grade students age 10-12 years (20 girls, 11 boys) who were healthy and active volunteered for participation. The training program consisted of 13 weeks of aerobic activities three days a week, 25 minutes per session, with training intensity assessed by heart rate monitors. Serum lipids and maximal oxygen uptake (VO2max) were measured at the beginning of a control period, 13 weeks later at the beginning of the training program, and at the termination of 13 weeks of training. VO2max values for the group improved 5.4%, but no significant changes were observed in any of the blood lipid levels between the control and training periods. These findings suggest that aerobic training of 13-weeks duration is not an effective means of altering blood lipids in healthy normolipemic children.

As used currently (BP and TOT only), the Wilks formula appears to be a valid method to adjust powerlifting scores by body mass.