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Zhen-Bo Cao, Nobuyuki Miyatake, Tomoko Aoyama, Mitsuru Higuchi and Izumi Tabata

Background:

The purpose was to develop new maximal oxygen uptake (VO2max) prediction models using a perceptually regulated 3-minute walk test.

Methods:

VO2max was measured with a maximal incremental cycle test in 283 Japanese adults. A 3-minute walk test was conducted at a self-regulated intensity corresponding to ratings of perceived exertion (RPE) 13.

Results:

A 3-minute walk distance (3MWD) was significantly related to VO2max (r = .60, P < .001). Three prediction models were developed by multiple regression to estimate VO2max using data on gender, age, 3MWD, and either BMI [BMI model, multiple correlation coefficients (R) = .78, standard error of estimate (SEE) = 5.26 ml⋅kg-1⋅min-1], waist circumference (WC model, R = .80, SEE = 5.04 ml⋅kg-1⋅min-1), or body fat percentage (%Fat model, R = .84, SEE = 4.57 ml⋅kg-1⋅min-1), suggesting that the %Fat model is the best model [VO2max = 37.501 + 0.463 × Gender (0 = women, 1 = men) – 0.195 × Age – 0.589 × %Fat + 0.053 × 3MWD]. Cross-validation by using the predicted residual sum of squares (PRESS) procedures demonstrated a high level of cross-validity of all prediction models.

Conclusions:

The new VO2max prediction models are reasonably applicable to estimating VO2max in Japanese adults and represent a quick, low-risk, and convenient means for estimating VO2max in the field.

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Liam P. Kilduff, Yannis P. Pitsiladis, Louise Tasker, Jeff Attwood, Paul Hyslop, Andrew Dailly, Ian Dickson and Stan Grant

This study examined the effects of Cr supplementation on muscle strength in conjunction with resistance training in nonresistance-trained males utilizing strategies previously reported in the literature to help optimize muscle Cr uptake. Nineteen nonresistance-trained males underwent 4 weeks of resistance training (3 days · week−1) while assigned to Cr (20 g · d−1 Cr + 140 g · d−1 glucose) for 7 days (loading), followed by 5 g · d−1 Cr + 35 g · d−1 glucose for 21 days (maintenance; n = 9) or placebo (160 g · d−1 glucose [loading] followed by 40 g · d−1 [maintenance; n = 10]). In subjects classified as “responders” to Cr on the basis of body mass changes (n = 7), the magnitude of change in 180∞ · s−1 isokinetic (p = .029) and isometric (p = .036) force was greater compared to the placebo group. A positive correlation was found between changes in body mass and 180º · s−1 isokinetic (loading: r = 0.68, p = .04; maintenance: r = 0.70, p = .037) and isometric (loading: r = 0.82, p < .01) force. Estimated Cr uptake was also positively correlated with changes in 60º · s−1 (r = 0.90, p < .01) and 180º · s−1 (r = 0.68, p = .043) isokinetic force, and isometric force (r = 0.71, p = .033). These results indicate that Cr supplementation can increase muscle strength (allied with 4 weeks of strength training) but only in subjects whose estimated Cr uptake and body mass are significantly increased; the greater the Cr uptake and associated body mass changes, the greater the performance gains.

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Mary K. Martin, David T. Martin, Gregory R. Collier and Louise M. Burke

We estimated self-reported energy intake (EI) and cycling energy expenditure (CEE) during racing and training over 26 days (9 days recovery [REC], 9 days training [TRN], and 8 days racing [RACE], which included a 5-day stage race) for 8 members of the Australian National Training Squad [mean ± SD; 25.1 ± 4.0 years, 59.2 ± 4.4 kg, 3.74 ± 0.24 L · min−1 V̇O2peak, 13.6 ± 4.5 % Body fat (%Bfat)]. After 70 days of training and racing, average body mass increased by 1.1 kg (95%CI 0.5 to 1.7 kg; p < .01) and average %Bfat decreased by 0.9% (95%CI –1.7 to –0.1%; p < .05). These minor changes, however, were not considered clinically significant. CEE was different between RACE, TRN, and REC (2.15 ± 0.18 vs. 1.73 ± 0.25 vs. 0.72 ± 0.15 MJ · d−1, p < .05). Reported EI for RACE and TRN were higher than REC (14.87 ± 3.03, 13.70 ± 4.04 vs.11.98 ± 3.57 MJ · d−1, p < .05). Reported intake of carbohydrate for RACE and TRN were also higher than REC (588 ± 122, 536 ± 130 vs. 448 ± 138 g · d−1, p < .05). Reported intake of fat (59 ± 21–68 ± 21 g · d−1) was similar during RACE, TRN, and REC, whereas protein intake tended to be higher during TRN (158 ± 49 g · d−1) compared to RACE and REC (136 ± 33; 130 ± 33 g · d−1). There was a relationship between average CEE and average EI over the 26 days (r = 0.77, p < .05), but correlations between CEE and EI for each of the women varied (r =–0.02 to 0.67). There was a strong trend for an inverse relationship between average EI and %Bfat (r = –.68, p = .06, n = 8). In this study, increases in reported EI during heavy training and racing were the result of an increase in carbohydrate intake. Most but not all cyclists modulated EI based on CEE. Research is required to determine whether physiological or psychological factors are primarily responsible for the observed relationship between CEE and EI and also the inverse correlation between %Bfat and EI.

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Mandy Clark, Debra B. Reed, Stephen F. Crouse and Robert B. Armstrong

Little published data describe the dietary and physiological profiles of intercollegiate female soccer players; therefore, the purpose of this investigation was to report baseline dietary data, anthropometrics, and performance indices of soccer women during rigorous pre-season training (2 sessions/day) and then during the post-competitive season. Members of a NCAA Division I women’s soccer squad completed 3-day diet records, anthropometrics, and physical tests, including VO2peak. Average body mass was 62 kg with 16% body fat, and no significant pre to post differences were observed. Total energy, carbohydrate (CHO), protein, and fat intakes were significantly greater during the pre-sea-son. Pre-season energy intake met the DRI for females with an “active” lifestyle (37 kcal/kg). While CHO intake failed to meet minimum recommendations to promote glycogen repletion (7–10 g/kg), protein and fat intakes were above minimum recommendations. Pre- and post-season intakes of several micronu-trients were marginal (<75% of the DRI) including vitamin E, folate, copper, and magnesium. VO2peak significantly improved from pre- to post-season (42 and 50 ml/kg/min). In this study female soccer players appeared to meet caloric needs during periods of training but failed to meet minimum CHO and micronu-trient recommendations. Foods higher in protein and fat displaced more CHOrich and nutrient-dense foods within athletes’ energy requirements and satiety limits.

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Gabriel Lozano-Berges, Ángel Matute-Llorente, Alejandro Gómez-Bruton, Alejandro González-Agüero, Germán Vicente-Rodríguez and José A. Casajús

The assessment of percentage of body fat (%BF) is often performed in sport clubs to monitor body composition changes in the athletes during the season due to its relationship with physical fitness and performance ( Avlonitou et al., 1997 ). Anthropometry, bioelectrical impedance analysis, dual

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Stanley S.C. Hui, Neil Thomas and Brian Tomlinson

Background:

The impact of physical activity, aerobic fitness, and body composition on coronary heart disease (CHD) risk factors in Hong Kong Chinese adults has not been previously investigated.

Methods:

The study surveyed 707 randomly selected middle-age Hong Kong Chinese by telephone for Physical Activity Rating (PAR). Three hundred and sixteen respondents (age: 45.1 ± 8.1 y) participated in subsequent aerobic fitness testing (VO2max) and CHD risk factor screening.

Results:

More than 70% of respondents did not have sufficient levels of physical activity. Fifty percent of the men and 19.5% of the women had two or more CHD risk factors. PAR correlated poorly with VO2max and CHD risk factors. VO2max showed significant associations with CHD risk factors. The adjusted odds ratios of having CHD risk factors for unfit participants ranged from 1.11 to 6.61 as compared to fit participants. Obese but fit individuals demonstrated lower odds of CHD risk factors than the obese and unfit individuals. WC was found to be a stronger predictor for CHD risk factors than BMI.

Conclusions:

The prevalence of CHD risk factors in middle-age Chinese in Hong Kong was high and was related to levels of aerobic fitness and obesity.

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Veronica A. Mullins, Linda B. Houtkooper, Wanda H. Howell, Scott B. Going and C. Harmon Brown

This study describes the body composition, dietary nutrient intake, dietary practices, and biochemical indices of iron status of elite female American heptathletes during training. Four-day diet records and dietary practice questionnaires were obtained from 19 female heptathletes (26 ± 3 years) during the training season. Anthropometric measurements and fasting blood samples were obtained at the lowest phase of the training cycle. These athletes had a low body fat (13.8 ± 2.7%) and high fat-free mass to height ratios (33.0 ± 2.0 kg/m). Average nutrient intakes were > 67% of the reference intakes for all nutrients except vitamin E. Most dietary nutrient densities were higher than NHANES III nutrient densities for women 20–29 years old. More than 50% of the athletes took vitamin supplements and monitored their hydration status. Fifteen of the 17 athletes reported a normal menstrual cycle. Markers of biochemical iron status were all within the normal range. On average, these athletes were lean with high levels of fat free mass, adequate nutrient intakes, and normal biochemical indices of iron status. However, individual data reveals considerable variability within this group.

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Stacy D. Hunter, Mandeep S. Dhindsa, Emily Cunningham, Takashi Tarumi, Mohammed Alkatan, Nantinee Nualnim and Hirofumi Tanaka

Background:

Obesity is associated with arterial stiffening and diminished quality of life. Bikram yoga may be a feasible alternative to traditional exercise among obese individuals. Accordingly, the purpose of this study was to investigate the impact of Bikram yoga, a heated style of hatha yoga, on arterial stiffness in normal and overweight/obese adults.

Methods:

Forty-three (23 normal body mass index or BMI; 20 overweight/obese) apparently healthy participants completed an 8-week Bikram yoga intervention. Body composition was estimated via dual energy x-ray absorptiometry, arterial stiffness was measured via brachialankle pulse wave velocity, and health-related quality of life was assessed via RAND 36-Item Short Form survey at baseline and at the end of the 8-week intervention.

Results:

After the intervention, brachial-ankle pulse wave velocity decreased (P < .05) in overweight/obese participants while no such changes were observed in normal BMI participants. In the quality of life measures, emotional well-being improved (P < .05) in both groups, and general health improved (P < .05) only in the normal weight BMI group.

Conclusion:

Bikram yoga ameliorates arterial stiffness in overweight/obese adults and can positively impact quality of life regardless of BMI.

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Mark A. Leydon and Clare Wall

The purpose of this study was to determine the nutritional status, eating behaviors, and body composition of 20 jockeys working in the New Zealand Racing Industry. Seven-day weighed food records showed the mean daily energy intake for male and female jockeys was 6769 ± 1339 kJ and 6213 ± 1797 kJ, respectively. Energy and carbohydrate intakes were below the recommendations for athletes, and the jockeys did not meet the RDI for a number of micronu-trients. Of the jockeys, 67% used a variety of methods to "make weight". including: diuretics, saunas, hot baths, exercise, and the restriction of food and fluids. A number of jockeys (20%) showed signs of disordered eating. Forty-four percent of jockeys were classified as osteopenic, and a number of factors may have contributed to this outcome, namely: reduced calcium intake, delayed menarche (14.5 years) in female jockeys, alcohol intake, and smoking. Percent body fat of male and female jockeys was 11.7 ± 2.9 and 23.6 ± 3.8, respectively. Current weight restrictions imposed on jockeys by the horseracing industry impacts on their nutritional status, which may compromise their sporting performance and both their short- and long-term health.

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Felipe Fossati Reichert, Ana Maria Batista Menezes, Jonathan Charles Kingdom Wells, Ulf Ekelund, Fabiane Machado Rodrigues and Pedro Curi Hallal

Background:

Prospective studies on physical activity (PA), diet, and body composition in adolescents are lacking, particularly outside high-income countries.

Goals:

To describe the methods used to assess these variables in the 1993 Pelotas (Brazil) Birth Cohort and to discuss the fieldwork challenges faced and alternatives to overcome them.

Methods:

In 2006–07 a subsample of the 1993 Pelotas cohort was revisited. PA was estimated using questionnaires, a combined heart-rate and motion sensor (Acti-Heart), and the ActiGraph GT1M accelerometer. Diet was investigated by questionnaire. Total body water was determined by stable isotopes. Thirty individuals had their total energy expenditure assessed by doubly labeled water. All data were collected at participants’ home.

Results:

The logistics of the fieldwork and the difficulties in undertaking the study and alternatives to overcome them are presented. Preliminary analyses show that 511 individuals were traced (response rate = 90.0%). Compliance of both adolescents and their families for the motion sensors and body-composition measurements was excellent.

Conclusions:

The authors conclude that it is feasible to carry out high-quality studies on PA in developing countries. They hope the article will be useful to other researchers interested in carrying out similar studies.