An Exploratory Study of Bone Health Among Native Hawaiian Women in Rural Hawai'i.

INTRODUCTION: The purpose of this study was to obtain baseline data on bone mass density for Native Hawaiian women and to better understand the socio-cultural context for assessing bone health and risk of osteoporosis for this underserved population. METHOD: A sequential mixed-method design guided by Leininger's Culture Care Theory of Diversity and Universality consisted of two phases: (a) an initial exploratory focus group and (b) dual-energy X-ray absorptiometry (DEXA) scans and individual interviews. Data were analyzed using descriptive statistics and thematic analysis. RESULTS: Phase a (n = 12) suggested that Native Hawaiian women have limited knowledge of bone health, but recognize traditional and cultural ways of health. Phase b (n = 50) showed that Native Hawaiian women have healthy bones, according to the T-score results. The interviews suggested that perspectives of bone health are culturally anchored. DISCUSSION: Understanding cultural values and practices are vital for care. Preliminary recommendations for health professionals are included.

Travel related changes in performance and physiological markers: the effects of eastward travel on female basketball players.

[Purpose] Purpose of this study is to measure the changes in various physiological markers and performance criteria for women basketball players over the course of a travel heavy season. [Participants and Methods] Fifty one Division-II female basketball players and a control group of 54 females joined this study. Measurements began at the beginning of the competitive season and concluded with final measurements at the end of the competitive season. [Results] The female basketball players showed noticeable increases in resting salivary cortisol, visceral trunk fat, resting heart rate, and resting blood pressure. These athletes also showed diminishment in isokinetic force of leg muscles, particularly in knee flexion strength. Vertical jump measurements also indicated a slight diminishment. In contrast, the control group experienced none of the same changes. [Conclusion] Over the course of a grueling flight schedule in combination with a full-length basketball season, the female athletes in this study showed significant declinations in many indicators of overall health. It is concluded that resulting prolonged intermittent stress of a travel-heavy season can lead to significant changes in certain physiological markers with notable decreases in isokinetic force of leg muscle.

Physical activity level and body composition in a multiethnic sample of school children in Hawaii.

BACKGROUND: Obesity, particularly in Native Hawaiians, is an important health risk. A possible contributing factor to obesity is reduced physical activity levels. AIM: This study investigates the relationship between measured levels of physical activity and body composition in two grade cohorts of school children of Native Hawaiian/Pacific Islander (NHPI) and non-NHPI ethnicity. METHODS: A sample of 105 Kindergarteners and third graders were measured for adiposity, physical fitness, and physical activity levels. Ethnicity was determined from genealogical surveys. BMI, waist circumference (WC) and body fat percentage derived from air displacement plethysmography were used to evaluate adiposity. Maximal oxygen consumption (VO2max/kg) was estimated and total energy expenditure (TEE), physical activity level (PAL) and percentage of time inactive (PTI) were determined using the Flex-heart rate method. RESULTS: VO2max, but not TEE, PAL or PTI, was significantly correlated with BMI in Kindergarteners; while VO2max and PAL were negatively correlated with BMI, PAL was significantly negatively correlated with WC and PTI was positively correlated with fat percentage among third graders. There were no significant ethnic differences in VO2max, TEE, PAL or PTI. CONCLUSIONS: PAL and PTI are moderately related to adiposity measures, and there are no ethnic differences in physical activity or fitness measures in this sample.

Relationships of physical performance tests to military-relevant tasks in women.

PURPOSE: This investigation sought to determine the most predictive measures of performance on a repetitive box lifting task (RBLT) and load bearing task (LBT) among 123 women (aged ±4 years, height 165±7 cm, body mass 64±10 kg). METHODS: To determine the relationship of various predictors to performance on the RBLT and LBT, multiple regression analysis was conducted on body mass, height, leg cross-sectional area, upper and lower body muscular strength, lower body explosive power, upper and lower body local muscular endurance, and aerobic capacity. RESULTS: The mean±SD (range) number of repetitions for the RBLT was 86±23 (20-159). The mean±SD (range) time to complete the LBT was 2,054±340 seconds (1,307-3,447). The following equations were generated: RBLT (number of repetitions)=57.4+0.2(peak jump power)+0.4(number of pushups in 2 minutes)+0.15(number of repetitions during the squat endurance test)+1.39(one repetition maximal strength boxlift (kg))-0.04(2-mile run time (2MR) in seconds), R=0.81; standard error of the estimate (SEE)=14; LBT (in seconds)=1,831-4.28(number of repetitions during the squat endurance test)+0.95(2MR in seconds)-13.4(body mass), R=0.73; SEE=232. CONCLUSIONS: We found that the 2MR and squat endurance test were significant predictive factors for performance on both load carriage tasks. These data also imply that women's performance in combat-related tasks can be improved with training that targets muscular strength, power, and local muscular endurance in addition to aerobic capacity.

Measures of adiposity in two cohorts of Hawaiian school children.

BACKGROUND: Native Hawaiians have high rates of obesity and obesity-related diseases compared with non-Hawaiians in Hawaii, and the relation between this ethnic disparity in adiposity and socioeconomic status (SES) in children is unclear. AIM: The present study compared measures of adiposity in two cohorts of school children residing in the Hilo area of Hawaii and related these measures to parental reports of ethnicity, household income and parent educational attainment. SUBJECTS AND METHODS: All children in either Kindergarten (mean age 5.6 years) or third grade (mean age 8.7 years) in eight elementary schools in the Hilo area were invited to participate. A total of 125 children had anthropometric, bioelectric impedance and air displacement plethysmography measurements taken and their parents answered questions about household income, parental educational attainment and genealogical background that included ethnicity of ancestors. RESULTS: Boys and girls in both cohorts had stature approximately at the 50(th) percentile (Z-score = 0) of national samples (CDC data). Z-scores of BMI were elevated compared to the CDC reference curves, but were significantly higher in male Native Hawaiian children in the older cohort among whom nearly 50% had a BMI above the 95(th) percentile for age. In the younger cohort, there was no significant ethnic difference in adiposity measures. In the older cohort, Native Hawaiian boys had significantly higher adiposity measures than their classmates. Adiposity in third grade girls was significantly and inversely related to their father's educational attainment. Percentage of Hawaiian ancestry was not significantly related to adiposity measures. CONCLUSIONS: Ethnic disparity in adiposity among Native Hawaiians compared with non-Hawaiian age mates occurs after the age of 6 years, and is confined to males in this sample. For older girls, father's, but not mother's, educational attainment was inversely related to adiposity.

Relation between C-reactive protein levels and body composition in a multiethnic sample of school children in Hawaii.

OBJECTIVES: Adipose cells secrete proinflammatory cytokines that stimulate hepatic production of C-reactive protein (CRP). CRP levels are associated with adiposity levels in adults, adolescents, and older children but not in young children (age 2-3). This study examined the relation between CRP, adiposity, and cardiovascular and metabolic variables including blood pressure, glucose, and blood lipids in two young cohorts of children, averaging approximately 5.5 and 8.5 years, respectively. METHODS: Children (N = 125) from eight elementary schools in the multiethnic community of Hilo Hawaii were recruited to fill out questionnaires, undergo anthropometrics and air displacement plethysmography, have resting blood pressure measured, and provide a finger stick blood sample for analysis of CRP, glucose, and blood lipids. RESULTS: There were no significant differences between the cohorts in ethnic make up, household income, or parents' educational attainment. No significant relation was found between CRP and either adiposity or cardiovascular/metabolic variables in the younger cohort. However, significant correlations were found between CRP and adiposity measures and blood pressure in the older cohort. There was no marked difference in association of CRP with BMI versus waist circumference or waist-to-hip ratio. In neither cohort was CRP significantly related to glucose or blood lipids. CONCLUSIONS: Both amount of fat mass and time duration for possessing the adipose tissue may be important factors in determining the relation between CRP and both adiposity and blood pressure.

Creatine supplementation improves muscular performance in older women.

Muscle power and strength decrease with age leading to reduced independence and increased health risk from falls. Creatine supplementation can increase muscle power and strength. The purpose of this study was to examine the effects of 7 days of creatine supplementation on body composition, muscular strength, and lower-body motor functional performance in older women. Thirty 58-71 year old women performed three test sessions (T1-T3) each separated by one week. Each session consisted of one repetition maximum tests for bench press and leg press, and isometric hand-grip, tandem gait, upper-body ergometer, and lower-body ergometer tests. Following T2, subjects were assigned to a creatine monohydrate (0.3 g kg body mass(-1) for 7 days) (CR: 63.31 +/- 1.22 year, 160.00 +/- 1.58 cm, 67.11 +/- 4.38 kg) or a placebo (PL: 62.98 +/- 1.11 year, 162.25 +/- 2.09 cm, 67.84 +/- 3.90 kg) supplementation group. CR significantly (P < 0.05) increased bench press (1.7 +/- 0.4 kg), leg press (5.2 +/- 1.8 kg), body mass (0.49 +/- 0.04 kg) and fat free mass (0.52 +/- 0.05) and decreased completion time on the functional tandem gait tests from T2-T3. No significant changes were found for PL on any of the measured variables. No adverse side-effects were reported by either group. Short-term creatine supplementation resulted in an increase in strength, power, and lower-body motor functional performance in older women without any adverse side effects.

Influence of oral contraceptive use on growth hormone in vivo bioactivity following resistance exercise: responses of molecular mass variants.

The purpose was to examine effects of oral contraceptive (OC) use on plasma growth hormone (GH) responses to heavy resistance exercise. Sixty untrained women were placed into one of two groups: currently using OC (Ortho Tri-Cyclen) (n=25; mean+/-SD: 24.5+/-4.2y, 160.4+/-7.1cm, 64.1+/-11.3kg) or not currently using OC (NOC) (n=35; 23.6+/-4.6y, 165.9+/-6.0cm, 65.7+/-10.3kg). Participants performed an acute heavy resistance exercise test (AHRET; six sets of 10 repetition squats; 2min rest between sets) during days 2-4 of the follicular phase (NOC group) or of inactive oral contraceptive intake (OC group). Plasma was obtained before and immediately after AHRET and subsequently fractionated based on apparent molecular weight (>60kD, 30-60kD, and <30kD). GH was determined in unfractionated plasma and each plasma fraction using 4 methods: (1) Nichols Institute Diagnostics immunoradiometric assay (Nichols), (2) National Institute of Diabetes and Digestive Kidney Diseases (NIDDK) competitive radioimmunoassay, (3) DSL immunofunctional enzyme-linked immunoabsorbent assay (IFA) and (4) rat tibial line bioassay. GH increased (P<0.05) in all fractions post-AHRET for the Nichols, NIDDK, and IFA. The OC group displayed higher resting GH for the NIDDK, and higher exercise-induced GH for the IFA, Nichols, and NIDDK in unfractionated plasma and >60kD subfraction compared to NOC group. No differences were observed for the tibial line bioassay. OC use augmented immunological GH response to AHRET in unfractionated plasma and >60kD molecular weight subfraction. However, OC use only increased biological activity of GH in one of two bioassays. These data demonstrated that GH concentrations at rest and following exercise are assay-dependent.

Chronic resistance training in women potentiates growth hormone in vivo bioactivity: characterization of molecular mass variants.

This investigation determined the influence of acute and chronic resistance exercise on responses of growth hormone (GH) molecular variants in women. Seventy-four healthy young women (23 +/- 3 yr, 167 +/- 7 cm, 63.8 +/- 9.3 kg, 26.3 +/- 4.0% body fat) performed an acute bout of resistance exercise (6 sets of 10 repetition maximum squat). Blood samples were obtained pre- and postexercise. Resulting plasma was fractionated by molecular mass (fraction A, >60 kDa; fraction B, 30-60 kDa; and fraction C, <30 kDa) using chromatography. Fractionated and unfractionated (UF) plasma was then assayed for GH using three different detection systems (monoclonal immunoassay, polyclonal immunoassay, and rat tibial line in vivo bioassay). Subjects were then matched and randomly placed into one of four resistance exercise training groups or a control group for 24 wk. All experimental procedures were repeated on completion of the 24-wk resistance training programs. After acute exercise, immunoassays showed consistent increases in UF GH samples and fractions B and C; increases in fraction A using immunoassay were seen only in the monoclonal assay. No consistent changes in bioactive GH were found following acute exercise. Conversely, chronic exercise induced no consistent changes in immunoassayable GH of various molecular masses, whereas, in general, bioassayable GH increased. In summary, although acute exercise increased only immunoactive GH, chronic physical training increased the biological activity of circulating GH molecular variants. Increased bioactive GH was observed across all fractions and training regimens, suggesting that chronic resistance exercise increased a spectrum of GH molecules that may be necessary for the multitude of somatogenic and metabolic actions of GH.

Cardiovascular responses to a high-volume continuous circuit resistance training protocol.

The purpose of this investigation was to determine the level of cardiovascular stress elicited by continuous and prolonged circuit resistance training (CRT). Each of the 11 men who volunteered as a subject were tested to determine oxygen consumption and heart rate responses to a submaximal and maximal treadmill protocol and a CRT session consisting of 10 exercises and 10 repetitions at 40% of 1 repetition maximum (1RM) for each station with 4.6 circuits performed. The physiological stress of the CRT in this study was evident by the sustained heart rate of more than 70% of maximum for 16.6 minutes, with the last 12 minutes at more than 80%. Despite the large anaerobic component in CRT, Vo(2) was sustained at 50% or more of maximum for the final 12 minutes. Treadmill running, involving large muscle groups, increased Vo(2) more rapidly than CRT, where alternating larger and smaller muscle groups were used. In addition, at the same Vo(2) heart rate differed significantly between the 2 modes of activity. Heart rate in CRT was higher (at 165) than the heart rate of 150 found during treadmill running at the same 50% Vo(2). Such workouts may be used in a training cycle in classical linear periodization or in a nonlinear program day targeting local muscular endurance under intense cardiorespiratory conditions, which may help individuals develop enhanced toleration of physiological environments where high cardiovascular demands and higher lactate concentrations are present.

Changes in muscle hypertrophy in women with periodized resistance training.

PURPOSE: Adaptations of arm and thigh muscle hypertrophy to different long-term periodized resistance training programs and the influence of upper body resistance training were examined. METHODS: Eighty-five untrained women (mean age = 23.1 +/- 3.5 yr) started in one of the following groups: total-body training [TP, N = 18 (3-8 RM training range) and TH, N = 21 (8-12 RM training range)], upper-body training [UP, N = 21 (3-8 RM training range) and UH, N = 19, (8-12 RM training range)], or a control group (CON, N = 6). Training took place on three alternating days per week for 24 wk. Assessments of body composition, muscular performance, and muscle cross-sectional area (CSA) via magnetic resonance imaging (MRI) were determined pretraining (T1), and after 12 (T2) and 24 wk (T3) of training. RESULTS: Arm CSA increased at T2 (approximately 11%) and T3 (approximately 6%) in all training groups and thigh CSA increased at T2 (approximately 3%) and T3 (approximately 4.5%) only in TP and TH. Squat one-repetition maximum (1 RM) increased at T2 (approximately 24%) and T3 (approximately 11.5%) only in TP and TH and all training groups increased 1 RM bench press at T2 (approximately 16.5%) and T3 (approximately 12.4%). Peak power produced during loaded jump squats increased from T1 to T3 only in TP (12%) and TH (7%). Peak power during the ballistic bench press increased at T2 only in TP and increased from T1 to T3 in all training groups. CONCLUSIONS: Training specificity was supported (as sole upper-body training did not influence lower-body musculature) along with the inclusion of heavier loading ranges in a periodized resistance-training program. This may be advantageous in a total conditioning program directed at development of muscle tissue mass in young women.

Longitudinal tracking of muscular power changes of NCAA Division I collegiate women gymnasts.

Gymnastics relies upon power as a critical component of sports-specific fitness. The purpose of this study was to monitor long-term training adaptations in the power of National Collegiate Athletics Association Division I women gymnasts. Twenty members of a women's gymnastic team (aged 18-22) were tracked over 3 years with the first year a baseline year of testing. Whole body power for the counter-movement (CMJ) and squat (SJ) vertical jump was obtained via force plate analyses at 2 assessment time points during each year (February and November). Results showed significant (p < or = 0.05) and continued increases in peak power output in the CMJ and SJ at each biannual assessment. Improvements of 46% (+1010 W) for the CMJ and 43% (+900 W) for the SJ were observed at the end of the tracking period. Peak power for the CMJ and SJ were recorded at 3210 W (+/-350 W) and 3000 W (+/-152 W), respectively. Associated improvements in the time to peak power of 36% (-0.239 second) and 38% (-0.151 second) were also found for the CMJ and SJ. There were no significant changes in body mass or total skinfold thickness, however, a shift toward improved fat free mass (i.e., lean muscle mass) was apparent. These data underscore the importance that specificity, and more importantly power development, should play in the conditioning of collegiate women gymnasts' training programs.

Creatine supplementation improves muscular performance in older men.

PURPOSE: Creatine supplementation has been shown to enhance muscle strength and power after only 5-7 d in young adults. Creatine supplementation could therefore benefit older individuals because aging is associated with a decrease in muscle strength and explosive power. METHODS: We examined the effects of 7 d of creatine supplementation in normally active older men (59-72 yr) by using a double-blind, placebo-controlled design with repeated measures. After a 3-wk familiarization period to minimize learning effects, a battery of tests was completed on three occasions separated by 7 d (T1, T2, and T3). After T1, subjects were matched and randomly assigned into creatine (N = 10) and placebo (N = 8) groups. After T2, subjects consumed supplements (0.3 g x kg(-1) x d(-1)) for 7 d until T3. All subjects were tested for maximal dynamic strength (one-repetition maximum leg press and bench press), maximal isometric strength (knee extension/flexion), upper- and lower-body explosive power (6 x 10-s sprints on a cycle ergometer), and lower-extremity functional ability (timed sit-stand test and tandem gait test). Body composition was assessed via hydrostatic weighing, and blood samples were obtained to assess renal and hepatic responses and muscle creatine concentrations. RESULTS: No significant increases in any performance measures were observed from T1 to T2 with the exception of isometric right-knee flexion in the placebo group indicating stability in the testing protocols. Significant group-by -time interactions indicated the responses from T2 to T3 were significantly greater (P