Inter-individual variation in response to resistance training in cardiometabolic health indicators.

Resistance training (RT) may improve metabolic health; however, the extent of its effectiveness is constantly evaluated to assess improvements in the group means, thus obscuring the heterogeneous individual effects. This study investigated inter-individual variation in response to RT as reflected in metabolic health indicators and how age, sex, nutrition, and pre-training phenotypes are associated with such variabilities. METHODS: Previously collected data of men and women (39-73 years, 135 trained, 73 non-trained controls) were pooled for analysis. Measurements were taken twice before training to estimate individual day-to-day variations and measurement errors (n = 208). The individual responsiveness to the 21-week RT in cardiometabolic health indicators (ie, systolic blood pressure, high-density lipoprotein cholesterol (HDL-C), cholesterol and triglycerides) was determined. Body composition was estimated by bioimpedance and dietary intake according to 4-day food diaries. RESULTS: Metabolic responses to RT seemed to be highly individual, and both beneficial and unfavorable changes were observed. Large inter-individual variations in training response were not explained by a subject's age, sex, body composition, or nutritional status, with the exception of improvements in HDL-C, which were associated with simultaneous decreases in body fat in older women. The incidence of metabolic syndrome diminished following RT. CONCLUSION: This study showed that RT could improve some specific metabolic health indicators beyond normal day-to-day variations, especially in blood lipid profile. Further studies are needed to elucidate genetic and other mechanisms underlining the heterogeneity of RT responses. This knowledge may be useful in providing individually tailored exercise prescriptions as part of personalized preventative health care.

Investigation of Variations in the Human Urine Metabolome amongst European Populations: An Exploratory Search for Biomarkers of People at Risk-of-Poverty.

SCOPE: According to Eurostat 2016, approximately 119 million European citizens live at-risk-of-poverty (ROP). This subpopulation is highly diverse by ethnicity, age, and culture in the different EU states, but they all have in common a low income that could represent an increased risk of nutrient deficiencies due to poor nutritional habits. This study aims to investigate the human urine metabolome in the search of common biomarkers representing dietary deficiencies amongst European populations at ROP. METHODS AND RESULTS: 2732 urine samples were collected from 1391 subjects across five different European countries, including the United Kingdom, Finland, Italy, Lithuania, and Serbia, and analyzed using 1 H-NMR spectroscopy. The resulting urine metabolome data were explored according to study design factors including economic status, country, and gender. CONCLUSION: Partitioning of the effects derived from the study design factors using ANOVA-simultaneous component analysis (ASCA) revealed that country and gender effects were responsible for most of the systematic variation. The effect of economic status was, as expected, much weaker than country and gender, but more pronounced in Lithuania than in other countries. Citrate and hippurate were among the most powerful ROP biomarkers. The possible relationship between these markers and nutritional deficiencies amongst the ROP population is discussed.

Heterogeneity in resistance training-induced muscle strength and mass responses in men and women of different ages.

Physical activity recommendations for public health include typically muscle-strengthening activities for a minimum of 2 days a week. The range of inter-individual variation in responses to resistance training (RT) aiming to improve health and well-being requires to be investigated. The purpose of this study was to quantify high and low responders for RT-induced changes in muscle size and strength and to examine possible effects of age and sex on these responses. Previously collected data of untrained healthy men and women (age 19 to 78 years, n = 287 with 72 controls) were pooled for the present study. Muscle size and strength changed during RT are 4.8 ± 6.1 % (range from -11 to 30 %) and 21.1 ± 11.5 % (range from -8 to 60 %) compared to pre-RT, respectively. Age and sex did not affect to the RT responses. Fourteen percent and 12 % of the subjects were defined as high responders (>1 standard deviation (SD) from the group mean) for the RT-induced changes in muscle size and strength, respectively. When taking into account the results of non-training controls (upper 95 % CI), 29 and 7 % of the subjects were defined as low responders for the RT-induced changes in muscle size and strength, respectively. The muscle size and strength responses varied extensively between the subjects regardless of subject's age and sex. Whether these changes are associated with, e.g., functional capacity and metabolic health improvements due to RT requires further studies.

Association between obesity history and hand grip strength in older adults--exploring the roles of inflammation and insulin resistance as mediating factors.

BACKGROUND: To examine the association between obesity history and hand grip strength, and whether the association is partly explained by subclinical inflammation and insulin resistance. METHODS: Data are from 2,021 men and women aged 55 years and older participating in the representative population-based Health 2000 Survey in Finland. Body mass and body height, maximal hand grip strength, C-reactive protein, and insulin resistance based on homeostasis model assessment (HOMA-IR) were measured in a health examination. Recalled weight at 20, 30, 40, and 50 years of age were recorded to obtain a hierarchical classification of obesity history. Obesity was defined as body mass index ≥ 30 kg/m². RESULTS: Earlier onset of obesity was associated with lower hand grip strength (p < .001) after controlling for age, sex, education, smoking, alcohol use, physical activity, several chronic diseases, and current body weight. Based on adjusted logistic regression models, the odds (95% confidence interval) for very low relative hand grip strength were 2.76 (1.78-4.28) for currently obese, 5.57 (3.02-10.28) for obese since age of 50 years, 6.53 (2.98-14.30) for obese since age of 40 years, and 10.36 (3.55-30.24) for obese since age of 30 years compared with never obese participants. The associations remained highly significant even after adjusting for current C-reactive protein and HOMA-IR, but these variables had only minor role in explaining the association between obesity history and hand grip strength. CONCLUSIONS: Long-term exposure to obesity is associated with poor hand grip strength later in life. Maintaining healthy body weight throughout the life span may help to maintain adequate muscle strength in old age. Prospective studies with information on prior muscle strength are needed to examine in detail the causal association between obesity history and muscle strength.

Factors associated with maximal walking speed among older community-living adults.

BACKGROUND AND AIMS: The relative contribution of different domains on walking speed is largely unknown. This study investigated the central factors associated with maximal walking speed among older people. METHODS: Cross-sectional analyses of baseline data from the SCAMOB study (ISRCTN 07330512) involving 605 community-living ambulatory adults aged 75-81 years. Maximal walking speed, leg extensor power, standing balance and body mass index were measured at the research center. Physical activity, smoking, use of alcohol, chronic diseases and depressive symptoms were self-reported by standard questionnaires. RESULTS: The mean maximal walking speed was 1.4 m/s (range 0.3-2.9). In linear regression analysis, age, gender and body mass index explained 11% of the variation in maximal walking speed. Adding leg extensor power and standing balance into the model increased the variation explained to 38%. Further adjusting for physical activity, smoking status and use of alcohol increased the variation explained by an additional 7%. A minor further increase in variability explained was gained by adding chronic diseases and depressive symptoms to the model. In the final model, the single most important factors associated with walking speed were leg extensor power, standing balance and physical activity, and these associations were similar in men and women and in different body mass index categories. CONCLUSIONS: Lower extremity impairment and physical inactivity were the central factors associated with slow walking speed among older people, probably because these factors capture the influences of health changes and other life-style factors, potentially leading to walking limitations.

Hand-grip strength cut points to screen older persons at risk for mobility limitation.

OBJECTIVES: To determine optimal hand-grip strength cut points for likelihood of mobility limitation in older people and to study whether these cut points differ according to body mass index (BMI). DESIGN: Cross-sectional analysis of data. SETTING: Data collected in the Finnish population-based Health 2000 Survey. PARTICIPANTS: One thousand eighty-four men and 1,562 women aged 55 and older with complete data on anthropometry, hand-grip strength and self-reported mobility. MEASUREMENTS: Mobility limitation was defined as difficulty walking 0.5 km or climbing stairs. Receiver operating characteristic analysis was used to estimate hand-grip strength cut points for likelihood of mobility limitation. RESULTS: The overall hand-grip strength cut points for likelihood of mobility limitation were 37 kg (sensitivity 62%; specificity 76%) for men and 21 kg (sensitivity 67%; specificity 73%) for women. The effect of the interaction between hand-grip strength and BMI on mobility limitation was significant in men (P=.02), but no such interaction was observed in women (P=.16). In men, the most-optimal cutoff points were 33 kg (sensitivity 73%; specificity 79%) for normal-weight men, 39 kg (sensitivity 67%; specificity 71%) for overweight men, and 40 kg (sensitivity 57%; specificity 68%) for obese men. In women, BMI-specific hand-grip strength cutoff values was not markedly more accurate than the overall cutoff value. CONCLUSION: The hand-grip strength test is a useful tool to identify persons at risk of mobility limitation. In men, hand-grip strength cut points for mobility increased with BMI, whereas in women, only one hand-grip strength threshold was identified.

Perceived constraints on physical exercise among obese and non-obese older people.

OBJECTIVE: To examine what older obese people consider as constraints on their physical exercise and to determine whether these constraints can explain the differences in physical activity. METHODS: Six hundred nineteen community-living people aged 75-81 years living in Jyväskylä, Central Finland, in 2003 were included in these cross-sectional analyses. Weight and height were measured at the research center, and physical activity and perceived constraints on physical exercise were assessed using validated questionnaires. Participants were categorized as non-obese (n=436), moderately obese (n=127) or severely obese (n=56). RESULTS: The risk of physical inactivity was two times higher in the moderately obese group (OR 1.99, 95% CI 1.27-3.12) and over four times higher in the severely obese group (OR 4.58, 95% CI 2.55-8.24) compared to the non-obese group. Higher prevalence of comorbidities, pain, tiredness, fear of falling and injury, discomfort and feelings of insecurity when exercising explained almost half of the increased risk of physical inactivity of older severely obese people. CONCLUSIONS: Results suggest that physical activity promotion among older obese people may be well received as long as it focuses on factors that enable participation in physical activity and takes into account their constraints on physical activity.

Serum basal hormone concentrations and muscle mass in aging women: effects of strength training and diet.

This study examined the effects of strength training and diet on serum basal hormone concentrations and muscle mass in aging women. Fifty-one women age 49 to 74 y were divided into two groups: strength training and nutritional counseling (n = 25), and strength training (n = 26). Both groups performed strength training twice a week for 21 wk. Nutritional counseling was given to attain sufficient energy and protein intake and recommended intake of fat and fiber. We found that the cross-sectional area of the quadriceps femoris increased by 9.5 +/- 4.1% in the nutritional counseling group versus 6.8 +/- 3.5% in the strength training only group after training (P < 0.052). Nutritional counseling evoked dietary changes such as increases in the proportion of energy from protein and the ratio of polyunsaturated and saturated fatty acids. Strength training increased testosterone and testosterone/sex hormone-binding globulin ratio after the first half of training, but these returned to baseline values at the end of the entire training period. Changes in serum basal hormone concentrations did not differ between the groups. Our results support the conclusion that nutritional counseling can contribute to the increase in the muscle cross-sectional area during prolonged strength training in aging women.

Effects of strength training on muscle strength characteristics, functional capabilities, and balance in middle-aged and older women.

Progressive strength training can lead to substantial increases in maximal strength and mass of trained muscles, even in older women and men, but little information is available about the effects of strength training on functional capabilities and balance. Thus, the effects of 21 weeks of heavy resistance training--including lower loads performed with high movement velocities--twice a week on isometric maximal force (ISOmax) and force-time curve (force produced in 500 milliseconds, F0-500) and dynamic 1 repetition maximum (1RM) strength of the leg extensors, 10-m walking time (10WALK) and dynamic balance test (DYN.D) were investigated in 26 middle-aged (MI; 52.8 +/- 2.4 years) and 22 older women (O; 63.8 +/- 3.8 years). 1RM, ISOmax, and F0-500 increased significantly in MI by 28 +/- 10%, 20 +/- 19%, 31 +/- 34%, and in O by 27 +/- 8%, 20 +/- 16%, 18 +/- 45%, respectively. 10WALK (MI and O, p < 0.001) shortened and DYN.D improved (MI and O, p < 0.001). The present strength-training protocol led to large increases in maximal and explosive strength characteristics of leg extensors and in walking speed, as well to an improvement in the present dynamic balance test performance in both age groups. Although training-induced increase in explosive strength is an important factor for aging women, there are other factors that contribute to improvements in dynamic balance capacity. This study indicates that total body heavy resistance training, including explosive dynamic training, may be applied in rehabilitation or preventive exercise protocols in aging women to improve dynamic balance capabilities.

Effects of strength training and nutritional counseling on metabolic health indicators in aging women.

PURPOSE: Effects of strength training (ST) and nutritional counseling (NC) on metabolic health indicators were examined in 50 aging women. METHODS: Subjects performed ST for 21 weeks. NC was given to obtain sufficient energy and protein intake, and recommended intake of fat and fiber. RESULTS: NC increased intake of protein and polyunsaturated fat by 4.5% and 10.7% and decreased intake of saturated fat by 18.3%. Serum concentrations of total cholesterol (TC), LDL-cholesterol (LDL-C), total and HDL-cholesterol (HDL-C) ratio and triacylglycerols (TAG) decreased, and serum HDL-C increased in all subjects after ST. Respectively, systolic and diastolic blood pressure and serum insulin concentration decreased in all subjects. NC contributed to the decreases in levels of serum LDL-C after the first half of ST and serum TC and HDL-C ratio during both ST periods. Changes in serum TAG concentrations correlated positively with intake of carbohydrates, and negatively with monounsaturated fat in all subjects. Respectively, changes in serum TC levels were related to protein intake, and changes in serum HDL-C to intake of fat, and inversely to carbohydrate and protein in all subjects. Relationships between serum TC and HDL-C levels and protein intake were only observable in the ST+NC group. CONCLUSIONS: The long-term ST had favorable effects on serum lipids, lipoproteins, insulin concentration, and blood pressure. However, NC further contributed to positive changes in serum lipids and lipoproteins.

Combined creatine and sodium bicarbonate supplementation enhances interval swimming.

This study examined the effect of simultaneous supplementation of creatine and sodium bicarbonate on consecutive maximal swims. Sixteen competitive male and female swimmers completed, in a randomized order, 2 different treatments (placebo and a combination of creatine and sodium bicarbonate) with 30 days of washout period between treatments in a double-blind crossover procedure. Both treatments consisted of placebo or creatine supplementation (20 g per day) in 6 days. In the morning of the seventh day, there was placebo or sodium bicarbonate supplementation (0.3 g per kg body weight) during 2 hours before a warm-up for 2 maximal 100-m freestyle swims that were performed with a passive recovery of 10 minutes in between. The first swims were similar, but the increase in time of the second versus the first 100-m swimming time was 0.9 seconds less (p < 0.05) in the combination group than in placebo. Mean blood pH was higher (p < 0.01-0.001) in the combination group than in placebo after supplementation on the test day. Mean blood pH decreased (p < 0.05) similarly during the swims in both groups. Mean blood lactate increased (p < 0.001) during the swims, but there were no differences in peak blood lactate between the combination group (14.9 +/- 0.9 mmol.L(-1)) and placebo (13.4 +/- 1.0 mmol.L(-1)). The data indicate that simultaneous supplementation of creatine and sodium bicarbonate enhances performance in consecutive maximal swims.