Brisk walking improves endurance fitness without changing body fatness in previously sedentary women.

The purpose of this study was to examine the influence of brisk walking on endurance fitness and the amount and distribution of body fat in previously sedentary women. Twenty eight women [mean age (SEM): 44.9 (1.5) years] followed the walking programme for 1 year, whilst 16 acted as controls [age 44.4 (2.3) years]. Changes in endurance fitness were evaluated by measuring the oxygen uptake (VO2) at a reference blood lactate concentration of 2 mmol.l-1. Two 1.61-km field tests of walking were completed, one at maximal speed and one at a "brisk" speed, as well as a 1.61-km walk on a motorised treadmill. The amount and distribution of body fat was determined by hydrostatic weighing and anthropometry and energy intake was evaluated using the 7-day weighed food intake method. Walkers completed an average of 157 min.week-1 of brisk walking over the year. The following were increased in walkers, relative to controls: brisk walking speed [walkers 1.73 (0.05) m.s-1 vs 1.88 (0.07) m.s-1; controls 1.69 (0.05) m.s-1 vs 1.70 (0.05) m.s-1 at baseline and 12 months respectively, P < 0.01], maximal walking speed and VO2 at 2 mmol.l-1. In addition, brisk walking reduced heart rate and blood lactate concentration during stepping as well as during standard, submaximal treadmill walking. It did not modify either the amount or the distribution of body fat, despite an unchanged energy intake.     

Energy cost of walking and gait instability in healthy 65- and 80-yr-olds.

This study tested whether the lower economy of walking in healthy elderly subjects is due to greater gait instability. We compared the energy cost of walking and gait instability (assessed by stride to stride changes in the stride time) in octogenarians (G80, n = 10), 65-yr-olds (G65, n = 10), and young controls (G25, n = 10) walking on a treadmill at six different speeds. The energy cost of walking was higher for G80 than for G25 across the different walking speeds (P < 0.05). Stride time variability at preferred walking speed was significantly greater in G80 (2.31 +/- 0.68%) and G65 (1.93 +/- 0.39%) compared with G25 (1.40 +/- 0.30%; P < 0.05). There was no significant correlation between gait instability and energy cost of walking at preferred walking speed. These findings demonstrated greater energy expenditure in healthy elderly subjects while walking and increased gait instability. However, no relationship was noted between these two variables. The increase in energy cost is probably multifactorial, and our results suggest that gait instability is probably not the main contributing factor in this population. We thus concluded that other mechanisms, such as the energy expenditure associated with walking movements and related to mechanical work, or neuromuscular factors, are more likely involved in the higher cost of walking in elderly people.     

Therapeutic effects of maximal strength training on walking efficiency in patients with schizophrenia - a pilot study

ABSTRACT: BACKGROUND: Patients with schizophrenia frequently have disabling gait deficits. The net mechanical efficiency of walking (epsilonnet) is an accurate measure often used to evaluate walking performance. Patients with gait deficits have a reduced epsilonnet with excessive energy expenditure during sub-maximal walking. Maximal strength training (MST) improves epsilonnet in healthy individuals and is associated with reduced risk of mortality. The aim of this study was to investigate whether MST improves epsilonnet in patients with schizophrenia. METHODS: Patients (ICD-10 schizophrenia, schizotypal or delusional disorders (F20-F29)) were included in a non-randomized trial. Patients were assigned to one of two groups: 1) MST consisting of 4x4 repetitions at 85-90% one repetition maximum (1RM) performed in a leg press apparatus or 2) playing computer games (CG). Both groups carried out their activity three days per week for eight weeks. 1RM, epsilonnet at 60 watt walking, peak oxygen uptake (VO2peak), the Positive and Negative Syndrome Scale (PANSS) and the 36-items short form (SF-36) were measured pre and post intervention. RESULTS: The baseline epsilonnet was 17.3 +/- 1.2% and 19.4 +/- 3.0% in the MST (n = 6) and CG groups (n = 7), respectively, which is categorized as mechanical inefficiency. The MST group improved 1RM by 79 kg (p = 0.006) and epsilonnet by 3.4% (p = 0.046) more than the CG group. The MST group improved 1RM and epsilonnet, by a mean of 83 kg (p = 0.028) and 3.4% (p = 0.028), respectively. VO2peak at baseline was 34.2 +/- 10.2 and 38.3 +/- 9.8 ml * kg-1 * min-1 in the MST and CG groups, respectively, and did not change (p > 0.05). No change was observed in PANSS or SF-36 (p > 0.05). CONCLUSIONS: MST improves 1RM and epsilonnet in patients with schizophrenia. MST could be used as a therapeutic intervention for patients with schizophrenia to normalize their reduced epsilonnet.     

Determination of the optimal walking speed for neural relaxation in healthy elderly women using electromyogram and electroencephalogram analyses

The purpose of this study was to determine the walking speed which has the greatest influence on neural relaxation in healthy elderly women as determined by electromyogram (EMG) and electroencephalogram (EEG) analyses. Seven elderly female volunteers [mean age 68.5 (SD 3.95) years] served as subjects for this study. The EMG signals were recorded from the gastrocnemius (MG), soleus (SL) and tibialis anterior (TA) muscles while walking on a treadmill, starting at 40␣m · min⁻¹ and increasing 6 m · min⁻¹ incrementally for 10␣min. The turning point of muscle activities (by integrated EMG, iEMG_tp) was determined as the walking speed at the point at which the mean rate of change of iEMG (MG + SL + TA) abruptly increased. After the determination of iEMG_tp, the treadmill was set at three constant speeds, one corresponding to the speed for the iEMG_tp and two others 20% higher or lower than that for the iEMG_tp. The subjects then walked for 20 min at each of these speeds on 3 separate days and their EEG power spectrum data were obtained for frequencies from the 8 to 13 Hz (α-wave component, AWC). The mean of iEMG_tp for our subjects was at a mean walking speed of 64.7 (SD 7.9) m · min⁻¹. Considering the subjects' age and height, iEMG_tp was somewhat faster than their expected self-paced normal walking speed. There were no differences between the mean AWC values of the subjects prior to exercising at each of the three speeds. The mean AWC values after exercise were significantly (P < 0.01) greater than before. The extent of the increase in AWC at iEMG_tp was greater than those at slower speeds. Our data would suggest that walking exercise at the speed which corresponds with EMG evidence of iEMG_tp may induce the most significant relaxing effects in elderly women. Accepted: 11 September 1996     

Whole body vibration exercise improves body balance and walking velocity in postmenopausal osteoporotic women treated with alendronate: Galileo and Alendronate Intervention Trail (GAIT)

A randomized controlled trial was conducted to determine the effect of 6 months of whole body vibration (WBV) exercise on physical function in postmenopausal osteoporotic women treated with alendronate. Fifty-two ambulatory postmenopausal women with osteoporosis (mean age: 74.2 years, range: 51-91 years) were randomly divided into two groups: an exercise group and a control group. A four-minute WBV exercise was performed two days per week only in the exercise group. No exercise was performed in the control group. All the women were treated with alendronate. After 6 months of the WBV exercise, the indices for flexibility, body balance, and walking velocity were significantly improved in the exercise group compared with the control group. The exercise was safe and well tolerated. The reductions in serum alkaline phosphatase and urinary cross-linked N-terminal telopeptides of type I collagen during the 6-month period were comparable between the two groups. The present study showed the benefit and safety of WBV exercise for improving physical function in postmenopausal osteoporotic women treated with alendronate.     

Relationship of androgens to body composition, energy and substrate metabolism and aerobic capacity in healthy, young women

Objective

To evaluate the role of physiologic levels of androgens and their precursors in the regulation of body composition, energy and substrate metabolism and aerobic capacity in healthy, cycling, premenopausal women.

Experimental

We evaluated 30 young (27 ± 1 year) premenopausal, non-obese (23 ± 0.5 kg/m²), normally-cycling women, without clinical or chemical evidence of hyperandrogenism or hyperinsulinemia, for parameters of total and regional body composition, glucose tolerance, aerobic capacity and resting energy expenditure and substrate oxidation. Serum was assayed for androgens and androgen precursors by techniques optimized to assess the low androgen levels in this population.

Results

Higher serum testosterone levels correlated with greater fat mass (r = 0.377; p = 0.04), but not abdominal adiposity or other metabolic/physiologic variables. Additionally, dehydroepiandrosterone (DHEA) was negatively related to visceral fat content (r = −0.569; p = 0.02). Other serum androgens did not correlate with total or regional adiposity, skeletal muscle mass, aerobic capacity, glucose tolerance, or resting energy and substrate metabolism.

Conclusion

In this group of non-obese, premenopausal women with no clinical or chemical evidence of hyperandrogenemia, serum testosterone levels were positively related with fat mass, but not with abdominal adiposity; whereas, DHEA was negatively related to visceral adiposity. Our data suggest that within the normal physiologic range, testosterone is a predictor of overall adiposity, but that this effect does not appear to be associated with concomitant alterations in resting energy or substrate metabolism that could predispose to weight gain.     

Metabolic cost of generating muscular force in human walking: insights from load-carrying and speed experiments.

We sought to understand how leg muscle function determines the metabolic cost of walking. We first indirectly assessed the metabolic cost of swinging the legs and then examined the cost of generating muscular force during the stance phase. Four men and four women walked at 0.5, 1.0, 1.5, and 2.0 m/s carrying loads equal to 0, 10, 20, and 30% body mass positioned symmetrically about the waist. The net metabolic rate increased in nearly direct proportion to the external mechanical power during moderate-speed (0.5-1.5 m/s) load carrying, suggesting that the cost of swinging the legs is relatively small. The active muscle volume required to generate force on the ground and the rate of generating this force accounted for >85% of the increase in net metabolic rate across moderate speeds and most loading conditions. Although these factors explained less of the increase in metabolic rate between 1.5 and 2.0 m/s ( approximately 50%), the cost of generating force per unit volume of active muscle [i.e., the cost coefficient (k)] was similar across all conditions [k = 0.11 +/- 0.03 (SD) J/cm3]. These data indicate that, regardless of the work muscles do, the metabolic cost of walking can be largely explained by the cost of generating muscular force during the stance phase.     

Ghrelin improves body weight loss and skeletal muscle catabolism associated with angiotensin II-induced cachexia in mice

Ghrelin is a gastric peptide that regulates energy homeostasis. Angiotensin II (Ang II) is known to induce body weight loss and skeletal muscle catabolism through the ubiquitin-proteasome pathway. In this study, we investigated the effects of ghrelin on body weight and muscle catabolism in mice treated with Ang II. The continuous subcutaneous administration of Ang II to mice for 6days resulted in cardiac hypertrophy and significant decreases in body weight gain, food intake, food efficiency, lean mass, and fat mass. In the gastrocnemius muscles of Ang II-treated mice, the levels of insulin-like growth factor 1 (IGF-1) were decreased, and the levels of mRNA expression of catabolic factors were increased. Although the repeated subcutaneous injections of ghrelin (1.0mg/kg, twice daily for 5days) did not affect cardiac hypertrophy, they resulted in significant body weight gains and improved food efficiencies and tended to increase both lean and fat mass in Ang II-treated mice. Ghrelin also ameliorated the decreased IGF-1 levels and the increased mRNA expression levels of catabolic factors in the skeletal muscle. IGF-1 mRNA levels in the skeletal muscle significantly decreased 24h after Ang II infusion, and this was reversed by two subcutaneous injections of ghrelin. In C2C12-derived myocytes, the dexamethasone-induced mRNA expression of atrogin-1 was decreased by IGF-1 but not by ghrelin. In conclusion, we demonstrated that ghrelin improved body weight loss and skeletal muscle catabolism in mice treated with Ang II, possibly through the early restoration of IGF-1 mRNA in the skeletal muscle and the amelioration of nutritional status.     

Development and training of coordination skills in 11- to 19-year-old soccer players

The purpose of the study was to determine the specificity of the development and training of coordination skills (CSs) in 11- to 19-year-old soccer players (n = 600). Tests for soccer players’ CSs and technical skills and one- and two-year training experiments on targeted development of CSs were used. It was found that the period from 11 to 13 years of age was the most favorable for the development of CSs in soccer players, and the period from 14 to 16 years of age was the next most favorable. The use of special coordination training aimed at development of individual CSs led to a greater improvement, with the CS and technical skill parameters of athletes from the experimental groups being significantly higher (by 2.5–38.3 and 3.6–12.2%, respectively) than those of athletes from the control groups developing CSs by the traditional method using dexterity exercises.     

A 4-week choice foot speed and choice reaction training program improves agility in previously non-agility trained, but active men and women

Computerized agility training (CAT) products are frequently suggested to improve agility. However, these claims often are made without unbiased scientific support. Therefore, the purpose of this study was (a) to determine the reliability and effectiveness of a 4-week CAT training program on foot speed (FS) and choice reaction (REACT), and (b) to assess whether training on the CAT would facilitate the improvement of a separate change-of-direction (COD) test in non-agility-trained, but active, men and women. Twenty-three participants (15 men, 8 women) pre- and posttested on FS, REACT, and COD drills. Eleven of those participants (7 men, 4 women) engaged in 4 weeks of training on the FS and REACT drills (EX). The remaining 12 (8 men, 4 women) did not participate in the training and served as controls (CON). Coefficients of variation indicate strong precision for FS (6.9%) and REACT (2.6%). Test-retest reliability, as analyzed by intraclass correlations (ICC), were high for both FS and REACT (0.89). Significant test-by-group interactions were observed for all three tests: FS (p = 0.004), REACT (p = 0.011), and COD (p = 0.049). Post hoc analysis indicated that EX increased foot contacts for the FS drill (p = 0.006), whereas REACT and COD demonstrated decreases in time to completion (p = 0.013 and 0.038, respectively). The CON group did not improve on any of the tests. This study indicates that the chosen CAT is an accurate and reliable tool for measuring foot speed and reaction time. These data justify the use of this CAT in analyzing foot speed and reaction time. Altogether, 4 weeks of foot speed and reaction training on the chosen CAT produced improvements in overall agility in non-agility-trained, but active, men and women. These data warrant the integration of such a device into the training program of untrained athletes attempting to improve agility.     

Prolactin-induced gain in body weight in relation to caloric intake and energy expenditure in spotted munia

Prolactin, which induced significant gain in body weight and in the weight of the cervical and abdominal fat deposits had no effect on daily total food intake in spotted munia. The hormone changed the feeding pattern from a modal type to almost continuous feeding, increased whole body oxygen consumption of the birds, and had no effect on total hopping index. Prolactin-induced fattening, therefore seems due to neither an increased caloric intake, nor a decreased metabolic expenditure, but probably reflects better utilization of food.     

Resistance training increases total daily energy expenditure in disabled older women with coronary heart disease.

Physical activity energy expenditure (PAEE) is a determinant of prognosis and fitness in older patients with coronary heart disease (CHD). PAEE and total energy expenditure (TEE) are closely related to fatness, physical function, and metabolic risk in older individuals. The goal of this study was to assess effects of resistance training on PAEE, TEE, and fitness in older women with chronic CHD and physical activity limitations (N = 51, mean age: 72 + 5 yr). The study intervention consisted of a progressive, 6-mo program of resistance training vs. a control group condition of low-intensity yoga and deep breathing. The study interventions were completed by 42 of the 51 participants. The intervention group manifested a 177 +/- 213 kcal/day (+9%) increase in TEE, pre- to posttraining, measured by the doubly labeled water technique during a nonexercise 10-day period (P < 0.03 vs. controls). This was due to a 50 +/- 74 kcal/day (4%) increase in resting metabolic rate measured by indirect calorimetry (P < 0.01, P < 0.05 vs. controls) and a 123 +/- 214 kcal/day (9%) increase in PAEE (P < 0.03, P = 0.12 vs. controls). Resistance training was associated with significant increases in upper and lower body strength, but no change in fat-free mass, measured by dual X-ray absorptiometry, or left ventricular function, measured by echocardiography and Doppler. Women in the control group showed no alterations in TEE or its determinants. There were no changes between groups in body composition, aerobic capacity, or measures of mental depression. These results demonstrate that resistance training of 6-mo duration leads to an increase in TEE and PAEE in older women with chronic CHD.     

Age- and fitness-related differences in limb venous compliance do not affect tolerance to maximal lower body negative pressure in men and women.

Aging and chronic exercise training influence leg venous compliance. Venous compliance affects responses to an orthostatic stress; its effect on tolerance to maximal lower body negative pressure (LBNP) in the elderly is unknown. The purpose of this study was to determine the influence of age and fitness, a surrogate measure of exercise training, on calf venous compliance and tolerance to maximal LBNP in men and women. Forty participants, 10 young fit (YF; age = 22.6 +/- 0.5 yr, peak oxygen uptake = 57.1 +/- 2.0 ml.kg(-1).min(-1)), 10 young unfit (YU; 23.1 +/- 1.0 yr, 41.1 +/- 2.0 ml.kg(-1).min(-1)), 10 older fit (OF; 73.9 +/- 2.0 yr, 39.0 +/- 2.0 ml.kg(-1).min(-1)), and 10 older unfit (OU; 70.9 +/- 1.6 yr, 27.1 +/- 2.0 ml.kg(-1).min(-1)), underwent graded LBNP to presyncope or 4 min at -100 mmHg. By utilizing venous occlusion plethysmography, calf venous compliance was determined by using the first derivative of the pressure-volume relation during cuff pressure reduction. We found that the more fit groups had greater venous compliance than their unfit peers (P < 0.05) as did the young groups compared with their older peers (P < 0.05) such that OU < YU = OF < YF. LBNP tolerance did not differ between groups. In conclusion, these data suggest that aging reduces, and chronic exercise increases, venous compliance. However, these data do not support a significant influence of venous compliance on LBNP tolerance.     

Cardiovascular response to interval and continuous training in women.

Three groups of five women (age = 18--25 years) participated in a 12-week training program. Cardiovascular responses up to 85% VO2 max to interval (ITG) and continuous (CTG) training were studied in two groups, before training and after 4, 8, and 12 weeks of training four times per week. A control group was assessed before and after 6 and 12 weeks. Both exercise groups demonstrated significant increases in Cao2--Cvo2 after 8 weeks with only slight further increases after 12 weeks (CTG = 8.9%, ITG = 20.0% at 85% VO2 max). No significant changes were noted in either group in SV (+ 5 ml ITG, + 9 ml CTG) or in their Qc. These results indicated that, in response to high intensity training, women may demonstrate similar cardiovascular adaptations to training as have been observed for men.     

Prevalence of troublesome symptoms related to temporomandibular disorders and awareness of bruxism in 65- and 75-year-old subjects

doi: 10.1111/j.1741‐2358.2011.00558.x Prevalence of troublesome symptoms related to temporomandibular disorders and awareness of bruxism in 65‐ and 75‐year‐old subjects Objective: To assess the prevalence of three troublesome temporomandibular disorder (TMD) symptoms and awareness of bruxism in two cohorts of subjects aged 65 and 75 years. Background: Epidemiological studies have demonstrated varying prevalence of TMD symptoms. The results concerning elderly people are inconclusive. Material and methods: In 2007 identical questionnaires were sent to all subjects born in 1942 and 1932 living in two Swedish counties. The response rate was 73.1% for the 65‐ and 71.9% for the 75‐year‐old subjects, totally 9093 subjects. Results: The great majority reported no or only a few TMD problems. Less than 4% considered their TMD symptoms to be rather great or severe. The mean prevalence of TMD‐related symptoms and bruxism was greater in women than in men in both age groups. The 75‐year‐old women reported a marked lower prevalence of TMD symptoms and bruxism than the 65‐year‐old women, whereas the age differences were small among the men. Self‐reported bruxism was associated with a higher prevalence of TMD symptoms. Conclusions: The great majority of the subjects did not report any troublesome TMD related symptoms. However, 5.4% of the 65‐year‐old women and 3.8% of the 75‐year‐old women considered their symptoms severe or rather severe.     

PYY(3-36) reduces food intake and body weight and improves insulin sensitivity in rodent models of diet-induced obesity

The gut hormone peptide YY (PYY) was recently proposed to comprise an endogenous satiety factor. We have studied acute anorectic functions of PYY(3-36) in mice and rats, as well as metabolic effects of chronic PYY(3-36) administration to diet-induced obese (DIO) mice and rats. A single intraperitoneal injection of PYY(3-36) inhibited food intake in mice, but not in rats. We next investigated the effects of increasing doses (100, 300, and 1,000 microg.kg-1.day-1) of PYY(3-36) administered subcutaneously via osmotic minipumps on food intake and body weight in DIO C57BL/6J mice. Whereas only the highest dose (1,000 microg.kg-1.day-1) of PYY(3-36) significantly reduced food intake over the first 3 days, body weight gain was dose dependently reduced, and on day 28 the group treated with 1,000 microg.kg-1.day-1 PYY(3-36) weighed approximately 10% less than the vehicle-treated group. Mesenteric, epididymal, retroperitoneal, and inguinal fat pad weight was dose dependently reduced. Subcutaneous administration of PYY(3-36) (250 and 1,000 microg.kg-1.day-1) for 28 days reduced body weight and improved glycemic control in glucose-intolerant DIO rats. Neither 250 nor 1,000 microg/kg PYY(3-36) elicited a conditioned taste aversion in male rats.     

Effects of creatine supplementation and exercise training on fitness in men 55-75 yr old.

effect of oral creatine supplementation (CR; 5 g/day) in conjunction with exercise training on physical fitness was investigated in men between 55 and 75 yr of age (n = 46). A double-blind randomized placebo-controlled (PL) trial was performed over a 6-mo period. Furthermore, a subgroup (n = 20) completed a 1-yr follow-up. The training program consisted of cardiorespiratory endurance training as well as moderate resistance training (2-3 sessions/wk). Endurance capacity was evaluated during a maximal incremental bicycle ergometer test, maximal isometric strength of the knee-extensor muscles was assessed by an isokinetic dynamometer, and body composition was assessed by hydrostatic weighing. Furthermore, in a subgroup (PL: n = 13; CR: n = 12) biopsies were taken from m. vastus lateralis to determine total creatine (TCr) content. In PL, 6 mo of training increased peak oxygen uptake rate (+16%; P < 0.05). Fat-free mass slightly increased (+0.3 kg; P < 0.05), whereas percent body fat slightly decreased (-1.2%; P < 0.05). The training intervention did not significantly change either maximal isometric strength or body weight. The responses were independent of CR. Still, compared with PL, TCr was increased by approximately 5% in CR, and this increase was closely correlated with initial muscle creatine content (r = -0.78; P < 0.05). After a 1-yr follow-up, muscle TCr was not higher in CR than in PL. Furthermore, the other measurements were not affected by CR. It is concluded that long-term creatine intake (5 g/day) in conjunction with exercise training does not beneficially impact physical fitness in men between 55 and 75 yr of age.     

Longitudinal changes in energy expenditure and body composition in obese women with normal and impaired glucose tolerance

Our primary objective was to evaluate changes in energy expenditure and body composition in women with normal glucose tolerance (NGT) and gestational diabetes mellitus (GDM). A secondary objective was to examine the relationship between maternal leptin and nutrient metabolism. Fifteen obese women, eight with NGT and seven with GDM, were evaluated before conception (P), at 12-14 wk (E), and at 34-36 wk (L). Energy expenditure and glucose and fat metabolism were measured using indirect calorimetry. Basal hepatic glucose production was measured using [6,6-2H2]glucose and insulin sensitivity by euglycemic clamp. There was a significant increase (6.6 kg, P = 0.0001) in fat mass from P to L. There was a 30% (P = 0.0001) increase in basal O2 consumption (VO2, ml/min). There were no significant changes in carbohydrate oxidation during fasting or storage from P to L. There was, however, a significant (P = 0.0001) 150% increase in basal fat oxidation (mg/min) from P to L. Under hyperinsulinemic conditions, there were similar 25% increases in VO2 (P = 0.0001) from P to L in both groups. Because of the significant increases in insulin resistance from P to L, there was a significant (P = 0.0001) decrease in carbohydrate oxidation and storage. There was a net change from lipogenesis to lipolysis, i.e., fat oxidation (30-40 mg/min, P = 0.0001) from P to L. Serum leptin concentrations had a significant positive correlation with fat oxidation at E (r = 0.76, P = 0.005) and L (r = 0.72, P = 0.009). Pregnancy in obese women is associated with significant increases in fat mass and basal metabolic rate and an increased reliance on lipids both in the basal state and during the clamp. These modifications are similar in women with NGT and GDM. The increased reliance on fat metabolism is accompanied by a concomitant decrease in carbohydrate metabolism during hyperinsulinemia. The increase in fat oxidation may be related to increased maternal serum leptin.