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Biomedical subjects

P B Sparling

Publications and source records attributed to P B Sparling.

At least 19 recordsLinked to original sources
PubMed1998

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 men's vis-à-vis women's 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.

Databases as Topic↗
PubMed1998

Bone mineral density and body composition of the United States Olympic women's field hockey team.

OBJECTIVE: To evaluate total bone mineral density (BMD) and body composition (% fat) in world class women field hockey players, members of the 1996 United States Olympic team. METHODS: Whole body BMD (g/cm2) and relative body fatness (% fat) were assessed by dual energy x ray absorptiometry using a Lunar DPX-L unit with software version 1.3z. Body composition was also estimated by hydrostatic weighing and the sum of seven skinfolds. RESULTS: Mean (SD) BMD was 1.253 (0.048) g/cm2 which is 113.2 (4.0)% of age and weight adjusted norms. Estimates of body composition from the three methods were similar (statistically non-significant): 16.1 (4.4)% fat from dual energy x ray absorptiometry, 17.6 (3.2)% from hydrostatic weighing, and 16.9 (2.6)% from the sum of seven skinfolds. Mean fat free mass was approximately 50 kg. CONCLUSIONS: The mean whole body BMD value for members of the 1996 United States Olympic women's field hockey team is one of the highest reported for any women's sports team. Moreover, the mean fat free mass per unit height was quite high and % fat was low. In this group of world class sportswomen, low % fat was not associated with low BMD.

Absorptiometry, Photon↗
PubMed1997

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.

Abdomen↗
PubMed1996

Comparison of body composition and bone mineral measurements from two DXA instruments in young men.

The purpose of this study was to compare body-composition and whole-body, lumbar spine (LS), femoral neck (FN), trochanter, and Ward's triangle (WT) bone mineral measurements by using the Hologic QDR 1000W (DXAH) and the Lunar DPX-L (DXAL) dual-energy X-ray absorptiometry instruments. In addition, the ability of conversion equations to predict DXAH data from DXAL data were tested. Thirteen healthy young adult males (aged 22.2 +/- 3.6 y, 177.4 +/- 5.3 cm in height, and 72.7 +/- 9.6 kg in weight) were scanned on the same day by using DXAH and DXAL. Whereas measured body mass was not different (P > 0.05) between machines, whole-body fat mass [DXAH-DXAL (DXAdiff) = 1152 +/- 1395 g], percentage fat (DXAdiff = 1.5 +/- 1.7% of body mass), bone mineral density (BMD; DXAdiff = 0.016 +/- 0.023 g/cm2), and bone mineral content (BMC; DXAdiff = 316 +/- 50 g) were lower and whole-body fat-free soft tissue (FFST; DXAdiff = 1781 +/- 1859 g) was higher with DXAH than with DXAL. Lower fat mass (DXAdiff = 2145 +/- 855 g) and BMC (DXAdiff = 216 +/- 36 g) and higher FFST (DXAdiff = 1966 +/- 943 g) in the trunk were primarily responsible for the whole-body differences. Lower BMD and BMC values were found for LS (DXAdiff = 0.145 +/- 0.038 g/cm2 and 3 +/- 2 g, respectively), trochanter (DXAdiff = 0.100 +/- 0.044 g/cm2 and 1.7 +/- 1.0 g), and WT (DXAdiff = 0.195 +/- 0.061 g/cm2 and 1.93 +/- 0.51 g) with DXAH compared with DXAL. DXAH BMD of FN was also lower (DXAdiff = 0.141 +/- 0.032 g/cm2) than with DXAL. Only DXAH whole-body BMC and LS BMD were accurately predicted from DXAL with conversion equations. Predicted DXAH FN BMD was significantly lower than the actual DXAH value (P < or = 0.05), whereas the discrepancy between DXAH and DXAL actually increased for whole-body percentage fat and BMD (DXAdiff = 6.6 +/- 1.3% body mass and 0.020 +/- 0.025 g/cm2). In conclusion, lower whole-body fat mass, percentage fat, and BMC, and higher whole-body FFST with DXAH were due primarily to measurement differences in the trunk. Whereas conversion equations accurately predicted DXAH whole-body BMC and LS BMD from DXAL measurements in young adult males, they did not accurately predict DXAH, percentage fat, and BMD of the whole body and FN BMD.

Absorptiometry, Photon↗
PubMed1995

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.

Adult↗
PubMed1994

Level of physical activity and CHD risk factors in black South African men.

Coronary heart disease (CHD) is uncommonly low among black South Africans. Although dietary and genetic influences probably contribute to their favorable serum lipid profile, other cardioprotective factors may also play a significant role in explaining the low incidence of CHD. From a socioeconomic perspective, it appears that the black community engages in regular physical activity (PA) more so than other populations. Since data are lacking, our aim was to provide preliminary data on the association between PA and the traditional CHD risk factors. The sample consisted of 212 working, middle-aged men drawn from an epidemiological database on the African population of metropolitan Cape Town. Analysis of responses to basic questions on PA behavior indicated i) 43% of the sample were employed in jobs requiring moderate to strenuous PA, and ii) the most favorable blood pressure and serum lipid profiles were associated with low to moderate levels of habitual exercise. As this community becomes more urbanized, job-related PA as well as PA of daily living will decline. The need for sports and leisure-time PA programs will become more important and should be considered as part of a public health strategic plan.

Adult↗
PubMed1993

Selected scientific aspects of marathon racing. An update on fluid replacement, immune function, psychological factors and the gender difference.

Four topics are addressed: fluid/fuel replacement during the marathon, marathoning and susceptibility to infection, psychological aspects of elite marathoners and the gender gap in marathon performance. Although these topics are diverse, they all relate to practical questions raised by coaches and athletes. Evidence from laboratory and field studies indicates that it is advisable for marathoners to consume 800 to 1000 L/h of sports drink providing 45 to 60 g/h of carbohydrate. It is strongly suggested to practice fluid consumption during training sessions as it is probable that tolerance to drinking during running is a trainable adaptation. Epidemiological and clinical research support the concept that marathon training and racing increase the runner's risk of upper respiratory tract infections because of negative changes in immune function. Susceptibility to infection may be reduced by proper nutrition, adequate sleep, appropriate recovery between vigorous workouts and minimal exposure to sick people during periods of heavy training and major races. Although psychological research in this area is still limited, evidence suggests that elite marathoners rely primarily on associative strategies during competition while judiciously dissociating in order to cope with pain. It is recommended that coaches and athletes interested in employing psychological interventions seek assistance from professionals well trained in the fields of both psychology and exercise science. Will women soon outrun men? Over the past 2 decades societal views and training practices of women distance runners have changed greatly, yet certain performance-related biological differences between men and women are unlikely to change.

Disease Susceptibility↗
PubMed1993

Monitoring core temperature during exercise: ingestible sensor vs. rectal thermistor.

A telemetry monitoring system using an ingestible temperature sensor has recently become available commercially, but to our knowledge no published data on exercise applications have been reported. Consequently, core temperature was measured by both ingestible capsule sensors and standard rectal thermistors in six trained subjects (three cyclists, three runners) during 30 to 90 min of progressive cycling or treadmill exercise. Testing was conducted 3-9 h after ingestion of the capsule. The telemetered temperature was lower than the rectal temperature both at rest and during exercise in every subject, with resulting significant (p < 0.005) mean differences (+/- S.D.) of 36.91 (+/- 0.41) vs. 37.50 (+/- 0.21) and 38.01 (+/- 0.33) vs. 38.94 degrees C (+/- 0.24), respectively. The mean temperature difference increased by 58% from rest (0.59 degrees C) to peak exercise (0.93 degrees C). These preliminary findings demonstrate a consistently lower temperature from the capsule sensor located within the GI tract compared to rectal thermistors. Replication of these results and investigation into this disparity are necessary before these ingestible capsules should be used for routine monitoring of core temperature.

Adult↗
PubMed1992

Carbohydrate-electrolyte replacement improves distance running performance in the heat.

The effects of a 7% carbohydrate-electrolyte drink (CE) and an artificially sweetened placebo (P) on performance and physiological function were compared during a 40-km run in the heat. Eight highly trained male runners completed two runs on a measured outdoor course. The first 35 km of each run was performed at self-selected training pace and the last 5 km at race effort. Under a counterbalanced, double-blind design, subjects consumed 400 ml of either CE or P 30 min prior to exercise, and 250 ml every 5 km thereafter during the run. Rectal temperature, heart rate, rating of perceived exertion, sweat rate, and respiratory exchange ratio were similar during the run for CE and P. Serum Na+, K+, Cl-, total protein, osmolality, blood lactate, urea nitrogen, and % change in plasma volume were also similar for both drink conditions; however, blood glucose was significantly higher (P less than 0.01) with CE. Running performance in the last 5 km was significantly faster (P less than 0.03) during CE (21.9 min) compared with P (24.4 min). Subjects reported no differences in stomach upset, bloating, or nausea between P and CE. Results indicate that CE replacement elicits similar thermoregulatory and physiological responses during prolonged running in the heat but increases run performance and blood glucose when compared with P.

Adult↗
PubMed1991

Peak heart rates during maximal running and swimming: implications for exercise prescription.

Thirty-four college-age fitness swimmers, 19 males and 15 females, were maximally tested during treadmill running (TR) and tethered swimming (TS). A discontinuous, graded test protocol was used for both TR and TS with 2-min stages and 1-min rest periods. Peak HRs were obtained via a UNIQ CIC monitor during the last 120 s of each stage. Blood lactate was measured at 3 min post exercise using a YSI Model 27 Analyzer. TS peak HR was significantly lower (p less than 0.05) than both the age-predicted HRmax (220-age) and TR peak HR by 13 and 11 bt.min-1, respectively. Blood lactate for TS (8.0 mmol.l-1) and TR (8.1 mmol.l-1) were similar. Mean target heart rate range (THRR) calculated from TS peak HR (144-176 bt.min-1) was significantly lower than THRR calculated from age-predicted max HR (151-187 bt.min-1) and TR peak HR (151-186 bt.min-1). For young adult fitness swimmers, we suggest reducing the HRmax obtained from treadmill exercise or predicted from age by 12 bt.min-1. This correction appears to be a reasonable estimate of swimming HRmax that can be used for calculating exercise intensity.

Adolescent↗
PubMed1990

Carbohydrate-electrolyte replacement during a simulated triathlon in the heat.

Effects of a 7% carbohydrate-electrolyte drink (CE) or a flavored water placebo (P) on physiological function and performance were compared during a simulated triathlon (ST) in the heat. Ten trained male triathletes performed two STs, consisting of 1.5 km swimming, 40 km cycling, and 10 km running in an environmentally controlled area at self-selected race pace. Subjects consumed 2 ml.kg-1 (130-174 ml) of CE or P following the swim, at 8.0-km intervals during cycling, and at 3.2-km intervals during running. Sweat rate, rectal and mean skin temperatures, perceived exertion, heart rate, plasma osmolality, percent change in plasma volume, total protein, Na+, K+, and lactate were similar during the ST under both drink conditions, but RER and plasma glucose were higher (P less than 0.05) with CE. During the last 4 km of running, VO2 was significantly higher with CE. Mean run time and total ST time were faster with CE (by 1.4 and 1.2 min) although not significantly different (P less than 0.06 and P less than 0.10) from P. Subjects reported no significant difference in nausea, fullness, or stomach upset with CE compared to P. General physiological responses were similar for each drink during 2 h of multi-modal exercise in the heat; however, blood glucose, carbohydrate utilization, and exercise intensity at the end of a ST may be increased with CE fluid replacement.

Bicycling↗
PubMed1990

Strength training in a cardiac rehabilitation program: a six-month follow-up.

The effect of circuit training on blood pressure (BP) and strength were evaluated for six months in 16 middle-aged (means = 55.8 years) men in a metropolitan cardiac rehabilitation program. Circuit training consisted of 12 to 20 repetitions at 30% to 40% of one repetition maximum on 12 Nautilus exercises with one-minute rests between exercises. This strength conditioning was supplemental to the patients' aerobic exercise. Five of the patients had myocardial infarctions, six had coronary artery bypass grafts, two had ventricular arrhythmias, one had angioplasty, and two had a complex of other cardiac conditions. Average height, weight, and body fat for the 16 patients were 179.3 cm, 82.4 kg, and 24.6%, respectively. Blood pressure (BP) data indicated no change in mean systolic or diastolic values during actual circuit training sessions (initial = 122/77 mmHg, mid = 124/78 mmHg, end = 122/76 mmHg). These data were compared with corresponding sets of BP at three and six months of training and no significant differences were seen. In no instance did circuit training appear to elevate a patient's BP above clinically acceptable levels for controlled hypertension. In the six months, significant increases in strength were observed with a mean increment of 8.2 kg or 22% for all 12 exercises. No changes occurred in body weight or percentage of fat. For selected patients in cardiac rehabilitation programs, a carefully supervised, long-term program of low-resistance strength training appears to be safe with regard to BP response, and beneficial in terms of strength gain.

Aged↗
PubMed1989

Does lung function limit performance in a 24-hour ultramarathon?

Based on observations of impaired lung function after marathon and ultramarathon running, it was hypothesized that the decline in running speed during a 24-h ultramarathon may be explained, in part, by ventilatory muscle fatigue. To test this hypothesis, ten competitors in the 1988 TAC/USA National 24-h Championship performed a battery of pulmonary function tests every 3 h during the race. The tests included measurement of inspiratory capacity, peak flow, forced vital capacity, forced expiratory volume in 1 sec, maximum voluntary ventilation for 12 sec (MVV12), and maximal respiratory pressures. Running speed was averaged over 3-h periods. MVV12 was significantly decreased (17%), but only after 24 h of running. All other ventilatory measures tended to decrease over time but the changes were not significant. However, after correcting for between-subject differences in running speed, the variance in MVV12 accounted for 39% (P less than 0.0001) of the variance in running speed. It was concluded that the decrease in ventilatory muscle endurance may constrain running speed in extremely prolonged running events.

Adult↗