The present study was undertaken (1) to evaluate to what extent percent body fat predicted from commonly used equations differs from that determined by hydrostatic weighing technique, and (2) to propose sample specific equations to predict percent body fat in obese women. Subjects were 51 adult obese women (23 sedentary women and 28 active women, mostly middle-aged) . Percent body fat (% fat) determined by hydrostatic weighing (densitometry) averaged 33.1±3.7%, while % fat velues (X=27.1-30.0 in sedentary women, 24.2-27.1 in active women, and 25.4-28.4 in all women) predicted from Nagamine equations were significantly lower and correlated in the order of only 0.1 to 0.6 with densitometry %fat. Of the eight equations developed for predicting % fat of obese women, Y=8.87+ 0.223 X₁-0.180 X₂ was considered the best choice, where X₂: Katsura Index and X₂ : sub-scapular skinfold (mm) . It is recommended that this equation or some other equations developed in the present study be applicable to a wide range of adult obese women. Caution is necessary, however, as to if those equations could be generalized to younger obese women.

A study was conducted to develop prediction equations for cardiorespiratory fitness (maximal oxygen uptake : VO_2max and oxygen uptake at anaerobic threshold : VO_2AT) in Japanese adult men and women. Eighty-three healthy men and 86 healthy women, aged 20-64 years (41.1±13.5 and 41.5±13.5, respectively), were recruited as subjects. Mean (±SD) of VO_2max and VO_2AT measured during a cycling test were 37.2±6.4 and 20.5±4.7 ml/kg/min, respectively, in men and 32.7±7.3 and 17.8±4.1 ml/kg/min, respectively, in women. In this study 36 kinds of equations applicable to each sex were developed using all the subjects (n=169) . These equations consisted of independent variables such as work rate divided by body weight (W/Wt), age and body fat percentage (%Fat), which were signficantly correlated with measured VO_2max and VO_2AT. Multiple correlation coefficients (R) and standard errors of estimate (SEE) of the equations ranged from 0.641 to 0.830 (P<0.05) and from 3.66 to 4.98 ml/kg/min, respectively, for VO_2max and from 0.661 to 0.815 (P<0.05) and from 2.77 to 3.20 ml/kg/min, respectively, for VO_2AT. Reliability coefficients (r) between the first and second tests were 0.911 in men and 0.873 in women for VO_2max, and 0.869 in men and 0.770 in women for VO_2AT, all of which were statistically significant (P<0.05) . It is concluded that the equations developed in the present study have the merits of simplicity, economy, accuracy and reliability. Furthermore, from the viewpoint of safety and convenience, the following prediction equations are recommended.
(Male)
VO_2max (ml/kg/min) =6.57 W_{RPE-legs 15}/Wt-0.19 Age-0.36%Fat+41.29
(R=0.830, SEE=3.66 ml/kg/min)
VO_2AT (ml/kg/min) =7.35 W_{RPE-legs 14}/Wt-0.06Age-0.23%Fat+15.62
(R=0.815, SEE=2.77 ml/kg/min)
(Female)
VO_2max (ml/kg/min) =7.30 W_{RPE-legs 15}/Wt-0.12 Age-0.46%Fat+37.32
(R=0.828, SEE =4.16 ml/kg/min)
VO_2AT (ml/kg/min) =5.03 W_{RPE-legs 14}/Wt-0.01 Age-0.16%Fat+14.15
(R=0.680, SEE=3.06 ml/kg/min)

Most people who go to fitness clubs or sports gyms for weight control, and many co-medicals and physicians believe that an increase in muscle mass and/or basal metabolic rate (BMR) is possible through a combination of regular exercise and optimal protein intake during weight loss. This seems a myth, and the reasons are discussed in this article. First, muscle mass is quite difficult to quantify. The limitations of body composition measurement should be well understood. Second, increasing muscle mass during weight loss is difficult. This might be attained through strict implementation of a protein-rich, low-carbohydrate diet; high-intensity resistance training; and aerobic exercise for a long duration. However, such a strict regimen is not feasible for most people. Finally, a 1-kg increase in muscle mass corresponds to an increase of only 13 kcal of BMR per day. Thus, an increase in muscle mass of 1 kg is difficult to achieve, while the gained BMR is approximately equivalent to a decrease of 13.5 kcal of BMR according to a 3-kg decrease of adipose tissue. Weight loss, unless through an extremely sophisticated weight control program, contributes to a decrease in BMR. However, it is an accomplished fact that women with significantly less muscle mass and lower BMR live longer than men with more muscle mass and higher BMR, regardless of ethnicity. Maintaining activities of daily living and daily activity function might be more essential.

Over the past two decades, a strong movement toward objective research (i.e., evidence-based medicine) has emerged in the fields of exercise science and physical education. It is now well-recognized that randomized, controlled trials (RCTs), when appropriately designed, represent the gold standard in medical studies and are usually considered of greatest evidentiary value for assessing the efficacy of interventions. RCTs are particularly effective for evaluation of drugs, devices, and procedures. In order to improve quality of reporting of RCTs, the consolidated standards of reporting trials (CONSORT) statement was developed in 1996 and use of the CONSORT statement has improved the reporting quality of RCTs over the past several years. However, RCTs are often not practical or not ethical for evaluating many public health interventions. Having a control group (no exercise, no diet, and/or no lifestyle modification) in intervention-based studies using unhealthy humans is definitely undesirable. There are viable options that should be used. For example, a trial having three groups (e.g., 1-day per week exercise group, 3-day per week exercise group, and 5-day per week exercise group) would be of more value for people with lifestyle-related diseases than having one group that does nothing. With these in mind, a paradigm shift in terms of designing health-related intervention studies for the fields of exercise science and physical education is proposed in this article.

Various studies have reported on VO₂max differences in men, with or without respect to distance run performances, and demonstrated that VO₂max was the most important factor in endurance work capacity. This study was undertaken to reveal whether VO₂max would still be the best determinant of endurance work capacity (or distance run performances), comparing it with AT parameters using the technique of correlational analyses. Twenty-seven distance runners, 16-26 years of age including an Olympic runner, underwent a multistage-incremental treadmill test for the assessment of submaximal and maximal work capacity. ATs were subjectively evaluated and determined as the point of breakaway of gas exchange criterion parameters according to Davis et al.'s method, and also referring to Wasserman et al.'s method.
The mean VO₂max was 4.518 l/mmn (70.1 ml/kg⋅BW/min, 78.1 ml/kg . LBM/min), whilst the mean AT appeared to be 3.444 l/mmn (52.8 ml/kg/min, 75.60% of VO₂max) . These results are in good agreement with previous results reported by others. Interestingly, all distance performances (i.e., 1-mile, 2-mile, and 3-mile) correlated highest with AT (ml/kg/min), secondly with exhaustion time, and thirdly with either VO₂max or another AT parameter. AT (ml/kg/min) alone accounted for approximately 510, 73%, and 80% of the variance in the 1-mile, 2-mile, and 3-mile performances, respectively.
Since absolute VO₂max is known to be a function of body size (e.g., body weight), an attempt was made to evaluate the relationships between the metabolic parameters and the distance performances through partial correlations holding the influence of body weight or LBM statistically constant. As a result, the correlation of VO₂max (1/mm) with the 3-mile performance increased considerably to r_p=-0.781 ; however, the degree of the relationship was not greater than the zero-order correlation (r=-0.896) obtained between AT (ml/kg/min) and the performance. Furthermore, when entered into a forward selection multiple regression with the 3-mile performance as the dependent variable, AT (l/min) accounted for only an additional 0.8% of the variance. VO₂max (l/min), true % 02, % body fat body weight, VO₂max (ml/kg/min), and vital capacity also accounted for only an additional 0.1%, 0.4%, 0.5%, 0.8%, 1.8%, and 1.8% of the variance, respectively. These data indicate that, considering the sample studied and limitations within this study, AT (ml/kg/min) could be the most significant determinant of the 3-mile run performance and, though to a lesser extent, the 2-mil eand 1-mile run performances.

Principal component analysis was used to estimate the physical fitness age (PFA) of middle-aged and elderly men from eight physical fitness variables. The subjects were 184 Japanese men, aged 20 to 75 years, who were recruited in a series of physical fitness tests including oxygen uptake corresponding to lactate threshold (Vo₂@LT) and maximal oxygen uptake (Vo₂max) . The subjects were categorized into three groups : those (n=134) considered apparently healthy, those (n=35) employed as a cross-validation sample, and 15 patients with coronary heart disease (CHD) . The equation developed for estimation of PFA in healthy individuals (n=134) was PFA=-15.3 PFS+48.0+Z, PFS=0.021 X₁+0.037 X₂+0.020 X₃+0.024 X₄+0.017 X₅+0.017 X₆+0.008 X₇+0.016 X₈-4.92, Z =0.12 Age-5.8; where PFS=physical fitness score, X₁=V_o2max (ml/kg/min), X₂=Vo₂@LT (ml/kg/min), X₃=grip strength (kg), X₄=side step (reps/20s), X₅=trunk extension (cm), X₆=trunk flexion (cm), X₇=foot balance with eyes closed (s), and X₈=vertical jump (cm) . Analyses of the data revealed that healthy individuals had PFAs (47.7±17.5yr) similar to their chronological ages (CA: 48.0±15.3yr) . In the cross-validation sample, it was confirmed that no difference existed between PFA (51.5±13.8yr) and CA (52.1±11.8yr) . CHD patients, however, had PFAs approximately 15 years older than their CAs (57.7±11.5vs. 72.2±12.3yr) . Since independent variables of the above equation consisted of various physical fitness elements, we defined the score as an index of “physical fitness age”. The importance and usefulness of PFA were discussed in more detail.

To determine the minimum duration of exercise for improving the aerobic capacity of patients with coronary heart disease (CHD), 23 female patients with CHD and/or hypertension, aged 52.8±8.7 years, were studied. After pre-testing, all the patients were conditioned for 4 months in order to elicit improvements in their aerobic capacity and other healthrelated factors. Duration and contents of daily activities were recorded by each patient. After 4 months, oxygen uptake at lactate threshold (VO_2LT) and VO_2peak were increased significantly from 12.9±2.6 to 16.0±3.4ml/kg/min and from 18.5±4.2 to 22.3±5.6ml/kg/min, respectively. Duration of exercise conditioning for the 4 months averaged 23.8±12.2min per day, ranging from 4.6 to 49.7min. Correlational analyses were applied in order to determine the extent to which the improvement in aerobic capacity was associated with the individual mean duration of exercise conditioning. As a result, changes in VO_2LT and VO_2peak correlated significantly with the exercise duration (Pearson's r=0.51, Spearman's rho=0.47 for VO_2LT; Spearman's rho=0.58 for VO_2peak) . Both VO_2LT and VO_2peak tended to improve markedly when daliy exercise duration was 20 min or longer. Furthermore, it was shown that the improvement in aerobic capacity remained almost the same within a range of exercise duration of 20 to 60min. We suggest that the minimum exercise duration for improving the aerobic capacity of cardiac patients is 20 to 30min per day or 140min or more per week.

To estimate how much physical activity is needed to improve overall health status in female patients with ischemic heart disease (IHD), the dose-response relationship between the duration of daily aerobic exercise and change in vital age (VA) was assessed for 4 months of exercise training. VA was considered as an index of physical health status and was computed from various coronary risk facotrs and physical fitness elements. Eighteen female patients with IHD, aged 54.3±9.1 yrs, continued the supervised exercise training 1-2 d/wk and the self-controlled exercise training 1-5 d/wk for 4 months. The intensity of exercise was set at individually determined lactate threshold. Daily duration of aerobic type exercise calculated for each patient averaged 21.1±11.0min/d, rang ing from 4.6 to 46.7 min/d. After the 4-month exercise training, VA decreased from 59.6±12.1 yrs to 54.2±11.8 yrs (P<0.05) . Significant correlation was found between daily duration of exercise and the change in VA (Spearman's rho=-0.60 ; Pearson's r=-0.62) . In this relationship, 10 min/d of exercise induced the decrease in VA and no further decrease in VA was found over the 30 min/d of exercise. In the 11 variables which constitute the equation of VA, oxygen uptake at lactate threshold (Spearman's rho=0.65; Pearson's r=0.64) and balancing on one leg with eyes closed (Spearman's rho=0.48; Pearson's r=0.51) significantly correlated with daily duration of aerobic exercise. From these results, it is suggested that the amount of moderate intensity exercise required to improve physical health status in female patients with IHD may be 10-30 minutes per day.