Teresa K. Snow

Physical Activity Patterns in Recent College Alumni

Within this sample of recent college alumni, a high proportion indicated that they enjoy exercise (66.1%) and felt confident in setting their own fitness programs (79.4%). Yet, only 34.3% reported engaging in recommended levels of moderate or vigorous PA. In contrast to previous reports, rates of participation in vigorous, moderate, and strengthening-type PA did not differ between men and women. Alumni who reported that they engaged in adequate levels of moderate or vigorous PA had gained significantly less weight in the years following graduation than those who reported being insufficiently active (3.0 kg vs. 6.1 kg). Last, we noted a strong positive association between PA patterns as college seniors and current PA behavior as recent alumni.

Evaluation of the Bod Pod® for assessing body fat in collegiate football players

PURPOSE The purpose of this investigation was to evaluate the accuracy of a new air displacement plethysmograph, BOD POD Body Composition System, for determining %fat in collegiate football players. METHODS Body fatness was estimated from body density (Db), which was measured on the same day using the BOD POD and hydrostatic weighing (HW) in 69 Division IA football players. In addition, 20 subjects were whole body scanned using dual-energy x-ray absorptiometry, DXA (Lunar DPX-L) to assess total body mineral content and %fat. Mineral content and HW determined Db were used to compute %fat from a three-component model (3C; fat, mineral, and residual). RESULTS Test-retest reliability for assessing %fat using the BOD POD (N = 15) was 0.994 with a technical error of measurement of 0.448%. Mean (+/- SEM) Db measured with the BOD POD (1.064 +/- 0.002 g x cc(-1) was significantly greater (P < 0.05) than HW (1.060 +/- 0.002 g x cc(-1)), thus resulting in a lower %fat for the BOD POD (15.1 +/- 0.8%) compared with HW (17.0 +/- 0.8%). Similar results (N = 20) were found for DXA (12.9 +/- 1.2%) and the 3C (12.7 +/- 0.8%) where %fat scores were significantly higher (P < 0.05) than scores determined using the BOD POD (10.9 +/- 1.0%). CONCLUSIONS Db measured with the BOD POD was higher than the criterion HW, thus yielding lower %fat scores for the BOD POD. In addition, BOD POD determined %fat was lower than DXA and 3C determined values in a subgroup of subjects. Assessment of %fat using the BOD POD is reliable and requires minimal technical expertise; however, in this study of collegiate football players, %fat values were underpredicted when compared to HW, DXA, and the 3C model.

The gender difference in distance running performance has plateaued : An analysis of world rankings from 1980 to 1996

PURPOSE Annual world rankings from 1980-1996 were used i) to determine if the gender difference in distance running events has stabilized, and ii) to examine whether the relative decline in pace as race distance increases is different between men and women. World best (WB) and 100th best times in the 1500 m and the marathon (42 km) for each of the 17 years were the indices used to represent overall trends in mens vis-à-vis womens distance running. METHODS These data were analyzed using regression analyses to develop and compare gender-specific equations. In the 1500 m, the gender difference in WB times (11.1 +/- 1.1%) was consistent from 1980 to 1996, and the slight rate of improvement in event depth (i.e., 100th rankings) was similar for men and women. RESULTS In the marathon, the gender difference in WB times (11.2 +/- 0.9%) was essentially the same as for the 1500 m. In 1980, the marathon was a fairly new event for the women, having only just been sanctioned by the International Amateur Athletics Federation (IAAF). As a consequence, the depth of the field increased quickly from 1980 to 1984. Since the mid-1980s, the rate of improvement for women in 100th-ranked times has leveled off to equal that of men. The average declines in relative pace for men and women from the 1500 m to the 10 km to the marathon were found to be remarkably similar with no diminishing of the gender difference as race distance increased. CONCLUSIONS Based on worldwide indices of competitive distance running, the gender difference in distance running performance has plateaued in recent years. Concomitantly, over the past decade, opportunities for women to train and compete have approached parity with those of men. It is likely that the current gender difference in performance will remain fairly constant because of biological differences between men and women that give men an advantage in distance running.

Use of air displacement plethysmography for estimating body fat in a four-component model.

PURPOSE To compare measurements of body density (D(b)) obtained from air displacement plethysmography (AP) and hydrostatic weighing (HW) and to determine the accuracy of substituting D(b) via AP (D(b)-AP) for D(b) via HW (D(b)-HW) in estimating body fatness (%Fat(4C)) and the composition and density of the fat-free mass (Dffm) from a four-component model (fat, mineral, water, and protein). METHODS D(b) was measured in 50 young adults using AP and HW. Total body water via deuterium dilution, bone mineral content via dual-energy x-ray absorptiometry, and D(b) were used to estimate %Fat(4C). RESULTS D(b)-AP and D(b)-HW were highly correlated (r = 0.89, SEE = 0.008 g x mL(-1)), but D(b)-AP (1.065 +/- 0.003 g x mL(-1)) was significantly higher (P < 0.05) than D(b)-HW (1.058 +/- 0.003 g x mL(-1)), resulting in a mean difference of 2.8%fat. Differences between %Fat(4C-AP) (17.8 +/- 1.2%) and %Fat(4C-HW) (19.3 +/- 1.2%) were significant (P < 0.05), but the SD of the differences (2.3%) was low. When D(b)-AP was used in a four-component model in place of D(b)-HW, the calculated Dffm was significantly higher (1.109 +/- 0.002 vs 1.105 +/- 0.002 g x mL(-1)) based on a higher (P < 0.05) protein fraction (22.0 +/- 0.4% vs 20.6 +/- 0.4%) and lower (P < 0.05) water (71.1 +/- 0.4% vs 72.4 +/- 0.4%) and mineral fractions (7.0 +/- 0.1% vs 7.1 +/- 0.1%). CONCLUSIONS AP yields a higher D(b) than HW and may not be a valid method for measuring D(b) or estimating %fat using densitometry. However, due to relatively small bias and low individual error, D(b)-AP is an acceptable substitute for D(b)-HW when estimating %fat with a four-component model in young adults.

Development of a Cadence Curl-Up Test for College Students

The purpose of this study was to evaluate a cadence curl-up test in a college population as compared to the American Alliance for Health, Physical Education, Recreation and Dance (AAHPERD) 1-min sit-up test (Association for Research and Professional Councils and Societies, 1985) and the Robertson 1-min curl-up test (Robertson & Magnusdottir, 1987). A cadence curl-up test, referred to as the GT curl-up test, was set at 25 repetitions per minute. A total of 205 college students completed three trials consisting of one AAHPERD sit-up trial and two GT curl-up trials. A subsample (n = 85) completed the Robertson curl-up test as a fourth trial. Trials were counterbalanced with 7 days rest between each test. To evaluate content validity, electromyography signals from selected muscle sites were measured on 6 participants for each of the three tests. Mean scores and standard deviations for the GT curl-up test, AAHPERD sit-up test, and Robertson curl-up test were M = 46.2, SD = 17.8; M = 46.4, SD = 10.2; and M = 69.7, SD = 14.1), respectively. Pearson product moment correlations among the three tests were low to moderate (r < or = .50). The intraclass correlation reliability estimate for the GT curl-up test was 0.92. In 1-min speed tests, repeated rapid trunk flexion can adversely affect technique and has raised safety concerns (Jette, Sidney & Cicutti, 1984; Faulkner, Sprigings, McQuarrie, & Bell, 1989; Cooper Institute for Aerobics Research, 1994). The Robertson test also requires the use of a curl-up frame. In the GT cadence test these drawbacks are minimized due to a slower, more controlled movement with an objective endpoint that is not dependent on special equipment. Moreover, our EMG findings supported previous reports that curl-up exercise with feet unanchored minimizes rectus femoris involvement. Based on the results of this study, the CT curl-up test was found to be a reliable field test with logical validity supporting its relevance as an index of abdominal muscular endurance among college students.

Serum Cholesterol Levels in College Students: Opportunities for Education and Intervention.

Elevated serum cholesterol levels have been shown to be associated with premature atherosclerosis in adolescents and young adults. The National Cholesterol Education Program recommends cholesterol screening for all adults aged 20 years or older, but normative data on the college-age population are limited. At a university where lipid profiles are made available to students in selected health/wellness courses, the authors analyzed and summarized lipid profiles on 1,088 undergraduates. Mean total cholesterol levels were similar for men (165 +/- 33 mg/dL) and women (168 +/- 27 mg/dL). The men, however, had significantly lower high-density lipoprotein (HDL) cholesterol and higher low-density lipoprotein (LDL) cholesterol than the women. One hundred twenty-one students (11.1% of the sample) had elevated serum cholesterol levels (LDL-C > or = 130 mg/dL). Cholesterol screening can be used as an educational tool for college students to reinforce the link between lipid levels and health habits.

Metabolic and thermoregulatory responses to a simulated American football practice in the heat

Energy cost is a major factor influencing the tolerable thermal load, particularly during exercise in the heat. However, no data exist on the metabolic cost of football practice, although a value of 35% of maximal aerobic capacity (&OV0312;O2max) has been estimated. The energy cost and thermoregulatory response of offensive linemen (OL) was measured wearing different American football ensembles during a simulated half of football practice in the heat. Five collegiate offensive linemen (133 kg, 20% fat, 42 ml·kg-1·min-1 maximal oxygen uptake) completed each of four 60-minute test sessions in an environmental chamber (28° C, 55% relative humidity [RH]) wearing shorts (S), helmet (H), helmet and shoulder pads (HS), and full gear (FUL). Core temperature in the digestive tract (TGI) was obtained using an ingestible sensor. During simulated football drills (e.g., repetitions of drive blocking), exercise intensity ranged from 30 to 81% &OV0312;O2max but averaged 55% &OV0312;O2max (6.7 METS) overall. Blood lactate remained >5 mmol·L-1, and heart rate (HR) averaged 79%HRmax. Equipment had a significant effect on %&OV0312;O2max but only during recovery between drills with HS (61.4 ± 3.7%) compared with H (53.3 ± 6.9%) and S (40.1 ± 8.5%). The TGI was higher (p > 0.05) with HS compared with H at several time-points after 30 minutes. Football practice for OL elicits a significantly higher overall metabolic cost (>6 METS, >50%&OV0312;O2max) than assumed in previous studies. The addition of shoulder pads increases core temperature and energy cost, especially during recovery between active drills in unacclimatized linemen.

Fluid intake in male and female runners during a 40‐km field run in the heat

To compare physiological responses, hydration status and exercise performance in similarly trained men and women in a hot, humid environment, 12 highly trained runners were studied during a simulated 40-km race. A 7% carbohydrate-electrolyte (CE) beverage was consumed prior to exercise (400 ml) and every 5 km (approximately 250 ml) during the run. The run times of the males and females did not differ significantly (173.5 +/- 8.5 and 183.8 +/- 4.2 min, respectively); nor did the rate of fluid intake relative to body mass (10.3 +/- 0.7 and 10.7 +/- 0.8 ml kg-1 h-1, respectively) or percent body mass loss (4.0 +/- 0.1% and 3.9 +/- 0.1%, respectively). During the run, %VO2 max, heart rate, concentrations of blood lactate, serum total protein and plasma osmolality were also similar for both groups. However, some significant sex differences (P < 0.05) were observed: the females had lower plasma volume losses and higher serum potassium and sodium concentrations than the males during the run. Rectal temperatures were lower in the female runners compared with the males during the last 10 km of the run (0.7 degrees C) and recovery (1.1 degrees C). Findings from this 40-km field run in hot, humid conditions suggest that CE fluid replacement at a relatively similar dosage (approximately 10 ml kg-1 h-1) may have sex-specific physiological effects. These observations warrant further investigation to assess the need for sex-specific fluid replacement guidelines.

Contractile mitral annular forces are reduced with ischemic mitral regurgitation.

OBJECTIVE Forces acting on mitral annular devices in the setting of ischemic mitral regurgitation are currently unknown. The aim of this study was to quantify the cyclic forces that result from mitral annular contraction in a chronic ischemic mitral regurgitation ovine model and compare them with forces measured previously in healthy animals. METHODS A novel force transducer was implanted in the mitral annulus of 6 ovine subjects 8 weeks after an inferior left ventricle infarction that produced progressive, severe chronic ischemic mitral regurgitation. Septal-lateral and transverse forces were measured continuously for cardiac cycles reaching a peak left ventricular pressure of 90, 125, 150, 175, and 200 mm Hg. Cyclic forces and their rate of change during isovolumetric contraction were quantified and compared with those measured in healthy animals. RESULTS Animals with chronic ischemic mitral regurgitation exhibited a mean mitral regurgitation grade of 2.3 ± 0.5. Ischemic mitral regurgitation was observed to decrease significantly septal-lateral forces at each level of left ventricular pressure (P < .01). Transverse forces were consistently lower in the ischemic mitral regurgitation group despite not reaching statistical significance. The rate of change of these forces during isovolumetric contraction was found to increase significantly with peak left ventricular pressure (P < .005), but did not differ significantly between animal groups. CONCLUSIONS Mitral annular forces were measured for the first time in a chronic ischemic mitral regurgitation animal model. Our findings demonstrated an inferior left ventricular infarct to decrease significantly cyclic septal-lateral forces while modestly lowering those in the transverse. The measurement of these forces and their variation with left ventricular pressure contributes significantly to the development of mitral annular ischemic mitral regurgitation devices.

Exercise and caffeine improve sustained attention following fatigue independent of fitness status

Background: Exercise improves cognition, but whether fitness status and caffeine modulate this effect remains unclear. Purpose: To determine if sustained attention is improved following exercise with and without caffeine in endurance-trained vs. sedentary adults. Methods: A continuous performance task (CPT), that is, a 20 min measure of sustained attention to assess accuracy and precision, was used to induce mental fatigue. Following the 20 min CPT, trained (n = 12) and sedentary (n = 12) participants completed either 30-min rest or 30-min moderate-intensity cycling below lactate threshold. Exercise trials were completed with placebo and caffeine (3 mg/kg) followed by cycling to volitional fatigue. Results: Exercise, as compared to rest, improved (p < .05) accuracy and precision after a mentally fatiguing task (CPT) and was not different between endurance-trained and sedentary groups. During the CPT, accuracy and precision declined (p < .05) with placebo, but both were maintained with caffeine following both exercise and cycling to volitional fatigue. Mental energy declined (p < .05) after the CPT with placebo but not caffeine. Cycling to volitional fatigue resulted in lower mental energy/greater mental fatigue as compared to baseline and following moderate intensity exercise, for both caffeine and placebo (p < .05). Conclusions: Exercise improved sustained attention following a mentally fatiguing attentional task independent of fitness status; and, when coupled with caffeine, provided greater benefit on the attentional task for accuracy, precision, and mental energy. Although caffeines beneficial effect on sustained attention persisted after cycling to volitional fatigue, it did not prevent a decline in mental energy/increase in mental fatigue.