2.Is it possible to increase muscle mass and basal metabolic rate during weight loss?
Japanese Journal of Physical Fitness and Sports Medicine 2017;66(3):209-212
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.
3.A PARADIGM SHIFT FOR DESIGNING HEALTH-RELATED INTERVENTION STUDIES IN EXERCISE SCIENCE AND PHYSICAL EDUCATION
KIYOJI TANAKA ; RYOSUKE SHIGEMATSU
Japanese Journal of Physical Fitness and Sports Medicine 2010;59(5):457-464
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.
4.Prediction of percent body fat in obese women.
KIYOJI TANAKA ; FUMIO NAKADOMO
Japanese Journal of Physical Fitness and Sports Medicine 1986;35(5):270-276
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.
5.DEVELOPMENT OF PREDICTION EQUATIONS FOR CARDIORESPIRATORY FITNESS USING RATINGS OF PERCEIVED EXERTION IN JAPANESE MEN AND WOMEN
TOMOHIRO OKURA ; KIYOJI TANAKA
Japanese Journal of Physical Fitness and Sports Medicine 1999;48(1):111-123
A study was conducted to develop prediction equations for cardiorespiratory fitness (maximal oxygen uptake : VO2max and oxygen uptake at anaerobic threshold : VO2AT) 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 VO2max and VO2AT 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 VO2max and VO2AT. 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 VO2max and from 0.661 to 0.815 (P<0.05) and from 2.77 to 3.20 ml/kg/min, respectively, for VO2AT. Reliability coefficients (r) between the first and second tests were 0.911 in men and 0.873 in women for VO2max, and 0.869 in men and 0.770 in women for VO2AT, 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)
VO2max (ml/kg/min) =6.57 WRPE-legs 15/Wt-0.19 Age-0.36%Fat+41.29
(R=0.830, SEE=3.66 ml/kg/min)
VO2AT (ml/kg/min) =7.35 WRPE-legs 14/Wt-0.06Age-0.23%Fat+15.62
(R=0.815, SEE=2.77 ml/kg/min)
(Female)
VO2max (ml/kg/min) =7.30 WRPE-legs 15/Wt-0.12 Age-0.46%Fat+37.32
(R=0.828, SEE =4.16 ml/kg/min)
VO2AT (ml/kg/min) =5.03 WRPE-legs 14/Wt-0.01 Age-0.16%Fat+14.15
(R=0.680, SEE=3.06 ml/kg/min)
7.Equations to estimate visceral adipose tissue volume by a single-slice method
Kiyoji Tanaka ; Rina So ; Tomoaki Matsuo
Japanese Journal of Physical Fitness and Sports Medicine 2017;66(5):335-344
Although it is common to assess visceral adipose tissue (VAT) by CT and MRI with a single slice at the umbilicus or the fourth and fifth lumbar vertebrae (L4-L5), recent studies reported that this single-slice method for determining an individual’s VAT may be inaccurate. Therefore, VAT accumulation should be based on total volume and determined with multiple slices rather than by cross-sectional area. However, obtaining multiple slices is burdensome for both subjects and analysts and lacks versatility despite its accuracy. The purpose of this study was to develop a new equation model for predicting VAT volume while maintaining the measurement accuracy of the multiple-slice method. We analyzed data from 214 Japanese male adults (48.5±9.3 years) and developed multiple, stepwise, linear regressions with VAT volume as a dependent variable and age, BMI, waist circumference and VAT areas (the standard L4-L5 measurement site 0 cm, +5 cm, +10 cm) as independent variables. From these results, we determined the best prediction equation for VAT volume as follows: VAT volume = (30.4×BMI) + (17.9×VAT area at L4-L5+10 cm) – 501.5. The model explained 93.1% of VAT variance and the predicted VAT volume significantly correlated with the measured VAT volume (r=0.97). This study developed a new VAT assessment method with a high level of accuracy. The method is significantly less burdensome in measurement and analysis than the multiple-slice method. Researchers can use this equation when they require an accurate evaluation of VAT accumulation. However, they should bear in mind that this equation was derived from data acquired from middle-aged, overweight and obese male subjects.
8.A correlational analysis of maximal oxygen uptake and anaerobic threshold as compared with middle and long distance performances.
KIYOJI TANAKA ; YOSHIYUKI MATSUURA ; TOSHIO MORITANI
Japanese Journal of Physical Fitness and Sports Medicine 1981;30(2):94-102
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 rp=-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.
9.Assessment of physical fitness age in middle-aged and elderly men.
MISOOK LEE ; YOSHIYUKI MATSUURA ; KIYOJI TANAKA
Japanese Journal of Physical Fitness and Sports Medicine 1993;42(1):59-68
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=Vo2max (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.
10.Minimum duration of exercise for improving aerobic capacity in middle-aged and elderly female patients with coronary heart disease and/or hypertension.
MASAKI TAKEDA ; KIYOJI TANAKA ; KATSUMI ASANO
Japanese Journal of Physical Fitness and Sports Medicine 1994;43(2):185-194
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 (VO2LT) and VO2peak 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 VO2LT and VO2peak correlated significantly with the exercise duration (Pearson's r=0.51, Spearman's rho=0.47 for VO2LT; Spearman's rho=0.58 for VO2peak) . Both VO2LT and VO2peak 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.