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Enhancement Effects of Tongkat Ali (Eurycoma longifolia) Supplementation on Performance Functions Following Strength Training in Middle-Aged Women
Abstract
The purpose of the study was to evaluate the effect of strength training and Tongkat Ali (Eurycoma longifolia) supplementation on muscular strength and performance functions in middle-aged women. Thirty-one middle-aged women successfully participated in this study. Participants were screened, matched, and assigned randomly to either experimental (n = 17) or control group (n = 14). Both groups followed a supervised strength training program twice a week for 12 weeks. Experimental group was given 100 mg of Tongkat Ali (Eurycoma Longifolia) for 12 weeks while the control group was given placebo. Participants completed five performance measures: 6-m walk, stair climb, chair rise, lift and reach, and 8 RM leg and chest press. Measurements were conducted pre- and postintervention. Strength was assessed using 8 RM leg and chest press. Mixed between-within ANOVA was utilized to determine the significance change (at a 95 % confidence level (p < 0.05)) of the outcome measures from pre- to post-test and between groups. The results demonstrated statistically significant changes in all the outcome measures in both groups. Significant difference between groups (p < 0.05) was observed only in stair climb. In conclusion, strength training counteracted the age-related decline in muscle strength, while Tongkat Ali supplementation did not enhance muscle strength gain in middle-aged women following a strength training program.
... To date, numerous studies have shown that usage of EL could promote lipid lowering and improvement in muscle strength. Studies on EL supplementation have been reported to enhance exercise performances by stimulating the effect of lipid mobilization and utilizations [3][4][5][6]. Due to its potential as ergogenic aids, many athletes have attempted to use EL as a supplement to improve exercise performances. ...
... In conclusion, EL supplementation at 1.7 mg/kg of body weight promotes lipid lowering following an endurance exercise. The amount and duration is safe as larger dosage and longer duration have been prescribed in other studies [3,5,6,11,18]. Thus, the study demonstrated support the ergogenic property of EL supplementation in terms of promoting lipolysis to provide better energy yield during endurance exercise in this subset of participants. ...
Studies have shown that usage of EL could promote lipid lowering and improvement in muscle strength. In view of that, lipid mobilization and utilizations would be the main mechanisms involved. The purpose of the investigation was to determine whether acute consumption of Eurycoma longifolia Jack extract would influence lipolysis among athletes. Ten male athletes were randomly assigned either to Eurycoma longifolia Jack group (EL, n = 5) or placebo group (PG, n = 5). Athletes from both groups ingested 1.7 mg/kg of body weight of either EL or PG for three days prior to the treadmill exercise test (65% of VO2max) for an hour. Plasma free fatty acid (FFA), glycerol and triglycerides (TG) levels were measured at pre-exercise and post-exercise on days 0 and 3. Plasma FFA in EL group was significantly lower than that in PG after 3 days (p < 0.05), and plasma glycerol level was significantly increased in EL compared to PG (p < 0.05). The results of this study suggest that EL supplementation could promote fat lipolysis, resulting towards better energy yield. Therefore, EL can be considered as an ergogenic aid to improve performances and to boost energy production.
... Regarding physical performance, it is evident that strength training offsets the decline in muscle strength associated with aging in middle-aged women. Yet, Tongkat Ali supplementation does not increase muscle strength gains following a strength training regimen [23]. Conversely, supplementing with Tongkat Ali may enhance muscle strength in physically active elderly men and women [3]. ...
Background: It has been suggested that supplementation with Tongkat Ali may affect testosterone concentrations; moreover, whether this influences body composition is unclear. Thus, the purpose of this investigation was to determine if four weeks of Tongkat Ali (400 mg daily dose) supplementation affected body composition and salivary free testosterone concentrations. Methods: Thirty-three exercise-trained males (n = 19) and females (n = 14) volunteered for this investigation (mean ± standard deviation: age 33.1 ± 13.0 years; height 171.1 ± 11.3 cm; body mass 77.4 ± 16.8 kg; average total years of training 13.9 ± 13.2; average hours of resistance training/week 4.2 ± 2.5; average hours of aerobic exercise/week 3.4 ± 2.8; average hours of other exercise/week 1.1 ± 2.0). Research participants were pre- and post-tested for body composition (InBody 270), Profile of Mood States (POMS), handgrip strength, and sleep (Pittsburgh Sleep Quality Index [PSQI]). In a subset of the research participants, saliva samples were collected and analyzed for cortisol and free testosterone. The research participants consumed 400 mg of Tongkat Ali or a placebo (rice flour) daily for four weeks. Results: There were no between-group differences (p > 0.05) for body composition (delta score, mean ± SD: lean body mass kg-treatment −0.5 ± 1.9, placebo −0.4 ± 0.7; fat mass kg-treatment −0.5 ± 1.6, placebo 0.3 ± 1.0, % fat treatment −0.1 ± 1.4, placebo 0.5 ± 1.1). Moreover, there were no differences between groups for any additional assessments (e.g., handgrip strength, mood, sleep, and salivary free testosterone and cortisol). Conclusions: Four weeks of supplementation with Tongkat Ali in exercise-trained males and females does not affect body composition, mood, sleep, vigilant attention, handgrip strength, cortisol, and free testosterone.
It is generally accepted that neural factors play an important role in muscle strength gains. This article reviews the neural adaptations in strength, with the goal of laying the foundations for practical applications in sports medicine and rehabilitation. An increase in muscular strength without noticeable hypertrophy is the first line of evidence for neural involvement in acquisition of muscular strength. The use of surface electromyographic (SEMG) techniques reveal that strength gains in the early phase of a training regimen are associated with an increase in the amplitude of SEMG activity. This has been interpreted as an increase in neural drive, which denotes the magnitude of efferent neural output from the CNS to active muscle fibres. However, SEMG activity is a global measure of muscle activity. Underlying alterations in SEMG activity are changes in motor unit firing patterns as measured by indwelling (wire or needle) electrodes. Some studies have reported a transient increase in motor unit firing rate. Training-related increases in the rate of tension development have also been linked with an increased probability of doublet firing in individual motor units. A doublet is a very short interspike interval in a motor unit train, and usually occurs at the onset of a muscular contraction. Motor unit synchronisation is another possible mechanism for increases in muscle strength, but has yet to be definitely demonstrated. There are several lines of evidence for central control of training-related adaptation to resistive exercise. Mental practice using imagined contractions has been shown to increase the excitability of the cortical areas involved in movement and motion planning. However, training using imagined contractions is unlikely to be as effective as physical training, and it may be more applicable to rehabilitation. Retention of strength gains after dissipation of physiological effects demonstrates a strong practice effect. Bilateral contractions are associated with lower SEMG and strength compared with unilateral contractions of the same muscle group. SEMG magnitude is lower for eccentric contractions than for concentric contractions. However, resistive training can reverse these trends. The last line of evidence presented involves the notion that unilateral resistive exercise of a specific limb will also result in training effects in the unexercised contralateral limb (cross-transfer or cross-education). Peripheral involvement in training-related strength increases is much more uncertain. Changes in the sensory receptors (i.e. Golgi tendon organs) may lead to disinhibition and an increased expression of muscular force. Agonist muscle activity results in limb movement in the desired direction, while antagonist activity opposes that motion. Both decreases and increases in co-activation of the antagonist have been demonstrated. A reduction in antagonist co-activation would allow increased expression of agonist muscle force, while an increase in antagonist co-activation is important for maintaining the integrity of the joint. Thus far, it is not clear what the CNS will optimise: force production or joint integrity. The following recommendations are made by the authors based on the existing literature. Motor learning theory and imagined contractions should be incorporated into strength-training practice. Static contractions at greater muscle lengths will transfer across more joint angles. Submaximal eccentric contractions should be used when there are issues of muscle pain, detraining or limb immobilisation. The reversal of antagonists (antagonist-to-agonist) proprioceptive neuromuscular facilitation contraction pattern would be useful to increase the rate of tension development in older adults, thus serving as an important prophylactic in preventing falls. When evaluating the neural changes induced by strength training using EMG recording, antagonist EMG activity should always be measured and evaluated.
Preliminary studies suggest that the menopause transition is associated with deleterious changes in body composition and abdominal fat distribution. Limitations of the methodology used in these studies, however, render their conclusions controversial. Thus, the present study used radiologic imaging techniques to examine the effect of menopausal status on body composition and abdominal fat distribution.
Cross-sectional.
Fifty-three healthy, middle-aged, premenopausal women (mean+/-SD; 47+/-3 y) and 28 early-postmenopausal women (51+/-4 y).
Total and regional body composition by dual energy X-ray absorptiometry and abdominal fat distribution by computed tomography.
No differences in total body fat-free mass or appendicular skeletal muscle mass were noted between groups. In contrast, total body fat mass was 28% higher (23+/-7 vs 18+/-7 kg) and percentage fat 17% higher (35+/-6 vs 30+/-9%; both P<0.01) in postmenopausal women compared with premenopausal women. Postmenopausal women had a 49% greater intra-abdominal (88+/-32 vs 59+/-32 cm2; P<0.01) and a 22% greater abdominal subcutaneous fat area (277+/-93 vs 227+/-108 cm2; P<0.05) compared to premenopausal women. The menopause-related difference in intra-abdominal fat persisted (P<0.05) after statistical adjustment for age and total body fat mass, whereas no difference in abdominal subcutaneous fat was noted. A similar pattern of differences in total and abdominal adiposity was noted in sub-samples of pre- and postmenopausal women matched for age or fat mass.
Our data suggest that early-postmenopausal status is associated with a preferential increase in intra-abdominal fat that is independent of age and total body fat mass. International Journal of Obesity (2000) 24, 226-231
To establish the prevalence of sarcopenia in older Americans and to test the hypothesis that sarcopenia is related to functional impairment and physical disability in older persons.
Cross-sectional survey.
Nationally representative cross-sectional survey using data from the Third National Health and Nutrition Examination Survey (NHANES III).
Fourteen thousand eight hundred eighteen adult NHANES III participants aged 18 and older.
The presence of sarcopenia and the relationship between sarcopenia and functional impairment and disability were examined in 4,504 adults aged 60 and older. Skeletal muscle mass was estimated from bioimpedance analysis measurements and expressed as skeletal muscle mass index (SMI = skeletal muscle mass/body mass x 100). Subjects were considered to have a normal SMI if their SMI was greater than -one standard deviation above the sex-specific mean for young adults (aged 18-39). Class I sarcopenia was considered present in subjects whose SMI was within -one to -two standard deviations of young adult values, and class II sarcopenia was present in subjects whose SMI was below -two standard deviations of young adult values.
The prevalence of class I and class II sarcopenia increased from the third to sixth decades but remained relatively constant thereafter. The prevalence of class I (59% vs 45%) and class II (10% vs 7%) sarcopenia was greater in the older (> or = 60 years) women than in the older men (P <.001). The likelihood of functional impairment and disability was approximately two times greater in the older men and three times greater in the older women with class II sarcopenia than in the older men and women with a normal SMI, respectively. Some of the associations between class II sarcopenia and functional impairment remained significant after adjustment for age, race, body mass index, health behaviors, and comorbidity.
Reduced relative skeletal muscle mass in older Americans is a common occurrence that is significantly and independently associated with functional impairment and disability, particularly in older women. These observations provide strong support for the prevailing view that sarcopenia may be an important and potentially reversible cause of morbidity and mortality in older persons.
To estimate the prevalence of physical limitations associated with diabetes among U.S. adults > or =18 years of age.
We conducted a cross-sectional analysis of the association between diabetes status and physical limitations using the 1997-1999 National Health Interview Survey (NHIS). Physical limitation was defined from self-reported degree of difficulty with nine tasks.
People with diabetes had a higher proportion of any physical limitation than did people without diabetes overall (66 vs. 29%, P < 0.001), for both men (59 vs. 24%, P < 0.001) and women (72 vs. 34%, P < 0.001). Compared with those without diabetes, a higher proportion of people with diabetes had some physical limitation among all age groups, and the difference declined (all P < 0.001) with increasing age (46 vs. 18% for 18-44 years, 63 vs. 35% for 45-64 years, 74 vs. 53% for 65-74 years, and 85 vs. 70% for those 75 years and older). After controlling for demographic characteristics and several other confounders, the odds ratio of physical limitation among adults with diabetes versus those without diabetes was 1.9 (95% CI: 1.8-2.1).
People with diabetes are much more likely to have a physical limitation than those without diabetes. Interventions are needed in this population to reduce progression from impairment to physical limitation and from physical limitation to disability, especially because the prevalence of diabetes is projected to increase dramatically in the next several decades.
Physical performance measures play an important role in the measurement of outcome in patients undergoing hip and knee arthroplasty. However, many of the commonly used measures lack information on their psychometric properties in this population. The purposes of this study were to examine the reliability and sensitivity to change of the six minute walk test (6MWT), timed up and go test (TUG), stair measure (ST), and a fast self-paced walk test (SPWT) in patients with hip or knee osteoarthritis (OA) who subsequently underwent total joint arthroplasty.
A sample of convenience of 150 eligible patients, part of an ongoing, larger observational study, was selected. This included 69 subjects who had a diagnosis of hip OA and 81 diagnosed with knee OA with an overall mean age of 63.7 +/- 10.7 years. Test-retest reliability, using Shrout and Fleiss Type 2,1 intraclass correlations (ICCs), was assessed preoperatively in a sub-sample of 21 patients at 3 time points during the waiting period prior to surgery. Error associated with the measures' scores and the minimal detectable change at the 90% confidence level was determined. A construct validation process was applied to evaluate the measures' abilities to detect deterioration and improvement at two different time points post-operatively. The standardized response mean (SRM) was used to quantify change for all measures for the two change intervals. Bootstrapping was used to estimate the 95% confidence intervals (CI) for the SRMs.
The ICCs (95% CI) were as follows: 6MWT 0.94 (0.88,0.98), TUG 0.75 (0.51, 0.89), ST 0.90 (0.79, 0.96), and the SPWT 0.91 (0.81, 0.97). Standardized response means varied from .79 to 1.98, being greatest for the ST and 6MWT over the studied time intervals.
The test-retest estimates of the 6MWT, ST, and the SPWT met the requisite standards for making decisions at the individual patient level. All measures were responsive to detecting deterioration and improvement in the early postoperative period.
It is generally accepted that neural factors play an important role in muscle strength gains. This article reviews the neural adaptations in strength, with the goal of laying the foundations for practical applications in sports medicine and rehabilitation. An increase in muscular strength without noticeable hypertrophy is the first line of evidence for neural involvement in acquisition of muscular strength. The use of surface electromyographic (SEMG) techniques reveal that strength gains in the early phase of a training regimen are associated with an increase in the amplitude of SEMG activity. This has been interpreted as an increase in neural drive, which denotes the magnitude of efferent neural output from the CNS to active muscle fibres. However, SEMG activity is a global measure of muscle activity. Underlying alterations in SEMG activity are changes in motor unit firing patterns as measured by indwelling (wire or needle) electrodes. Some studies have reported a transient increase in motor unit firing rate. Training-related increases in the rate of tension development have also been linked with an increased probability of doublet firing in individual motor units. A doublet is a very short interspike interval in a motor unit train, and usually occurs at the onset of a muscular contraction. Motor unit synchronisation is another possible mechanism for increases in muscle strength, but has yet to be definitely demonstrated. There are several lines of evidence for central control of training-related adaptation to resistive exercise. Mental practice using imagined contractions has been shown to increase the excitability of the cortical areas involved in movement and motion planning. However, training using imagined contractions is unlikely to be as effective as physical training, and it may be more applicable to rehabilitation. Retention of strength gains after dissipation of physiological effects demonstrates a strong practice effect. Bilateral contractions are associated with lower SEMG and strength compared with unilateral contractions of the same muscle group. SEMG magnitude is lower for eccentric contractions than for concentric contractions. However, resistive training can reverse these trends. The last line of evidence presented involves the notion that unilateral resistive exercise of a specific limb will also result in training effects in the unexercised contralateral limb (cross-transfer or cross-education). Peripheral involvement in training-related strength increases is much more uncertain. Changes in the sensory receptors (i.e. Golgi tendon organs) may lead to disinhibition and an increased expression of muscular force. Agonist muscle activity results in limb movement in the desired direction, while antagonist activity opposes that motion. Both decreases and increases in co-activation of the antagonist have been demonstrated. A reduction in antagonist co-activation would allow increased expression of agonist muscle force, while an increase in antagonist co-activation is important for maintaining the integrity of the joint. Thus far, it is not clear what the CNS will optimise: force production or joint integrity. The following recommendations are made by the authors based on the existing literature. Motor learning theory and imagined contractions should be incorporated into strength-training practice. Static contractions at greater muscle lengths will transfer across more joint angles. Submaximal eccentric contractions should be used when there are issues of muscle pain, detraining or limb immobilisation. The reversal of antagonists (antagonist-to-agonist) proprioceptive neuromuscular facilitation contraction pattern would be useful to increase the rate of tension development in older adults, thus serving as an important prophylactic in preventing falls. When evaluating the neural changes induced by strength training using EMG recording, antagonist EMG activity should always be measured and evaluated.
It is thought that resistance exercise results in an increased need for dietary protein however, data also exists to support the opposite conclusion. The purpose of this study was to determine the impact of resistance exercise training on protein metabolism in novices with the hypothesis that resistance training would reduce protein turnover and improve whole-body protein retention. Healthy males (n = 8, 22 1y, BMI = 25.3 1.8kgm²) participated in a progressive whole-body split routine resistance-training program 5d/week for 12 weeks. Before (PRE) and after (POST) the training, oral [¹⁵N]-glycine ingestion was used to assess nitrogen flux (Q), protein synthesis (PS), protein breakdown (PB), and net protein balance (NPB = PS PB). Macronutrient intake was controlled over a 5d period PRE and POST, while estimates of protein turnover and urinary nitrogen balance (Nbal = Nin urine Nout) were conducted. Bench press and leg press increased 40% and 50%, respectively (p < 0.01). Fat- and bone-free mass (i.e., lean muscle mass) increased from PRE to POST (2.5 0.8kg, p < 0.05). Significant PRE to POST decreases (p <0.05) occurred in Q (0.9 0.1 vs. 0.6 0.1gNkg¹d¹), PS (4.6 0.7 vs. 2.9 0.3gkg¹d¹), and PB (4.3 0.7 vs. 2.4 0.2gkg¹d¹). Significant training-induced increases in both NPB (PRE = 0.22 0.13 gkg¹d¹; POST = 0.54 0.08gkg¹d¹) and urinary nitrogen balance (PRE= 2.8 1.7g Nd¹; POST = 6.5 0.9g Nd¹) were observed. A program of resistance training that induced significant muscle hypertrophy resulted in reductions of both whole-body PS and PB, but an improved NPB, which favoured the accretion of skeletal muscle protein. Urinary nitrogen balance increased after training. The reduction in PS and PB and a higher NPB in combination with an increased nitrogen balance after training suggest that dietary requirements for protein in novice resistance-trained athletes are not higher, but lower, after resistance training.
Low grip strength is recognized as one of the characteristics of frailty, as are systemic inflammation and the sensation of fatigue. Contrary to maximal grip strength, the physical resistance of the muscles to fatigue is not often included in the clinical evaluation of elderly patients. The aim of this study was to investigate if the grip strength and the resistance of the handgrip muscles to fatigue are related to self-perceived fatigue, physical functioning and circulating IL-6 in independently living elderly persons.
Forty elderly subjects (15 female and 25 male, mean age 75 +/- 5 years) were assessed for maximal grip strength, as well as for fatigue resistance and grip work (respectively time and work delivered until grip strength drops to 50% of its maximum during sustained contraction), self perceived fatigue (VAS-Fatigue, Mob-Tiredness scale and the energy & fatigue items of the WHOQOL-100), self rated physical functioning (domain of physical functioning on the MOS short-form) and circulating IL-6. Relationships between handgrip performance and the other outcome measures were assessed.
In the male participants, fatigue resistance was negatively related to actual sensation of fatigue (VAS-F, p < .05) and positively to circulating IL-6 (p < .05). When corrected for body weight, the relations of fatigue resistance with self-perceived fatigue became stronger and also apparent in the female. Grip strength and grip work were significantly related with several items of self-perceived fatigue and with physical functioning. These relations became more visible by means of higher correlation coefficients when grip strength and grip work were corrected for body weight.
Well functioning elderly subjects presenting less hand muscle fatigue resistance and weaker grip strength are more fatigued, experience more tiredness during daily activities and are more bothered by fatigue sensations. Body weight seems to play an important role in the relation of muscle performance to fatigue perception. Elderly patients complaining from fatigue should be physically assessed, both evaluating maximal grip strength and fatigue resistance, allowing the calculation of grip work, which integrates both parameters. Grip work might best reflect the functional capacity resulting from the development of a certain strength level in relation to the time it can be maintained.
Changes in muscular fitness and metabolic health indicators were examined in 22 men (57.9 +/- 6.6 years, BMI 24.5 +/- 2.6 kg/m (2)) and 21 control men (58.2 +/- 6.1 years, BMI 25.4 +/- 2.8 kg/m (2)) during two consecutive 21-week periods: 1) whole body progressive strength training (ST: twice a week), and 2) continued reduced training (CRT: 3 ST sessions/2 weeks, n = 17 + 17). After the 21-week ST period, maximal strength of leg extensors increased in the ST group by 19.6 +/- 7.6 % vs. 2.8 +/- 4.4 % (p < 0.001) and also 10-m walking time and 10-step stair-climbing time shortened by - 17.2 +/- 7.6 % vs. 4.1 +/- 3.9 % (p < 0.01) and by - 8.2 +/- 6.8 % vs. - 3.0 +/- 6.8 % (p < 0.05) compared to the controls. Systolic blood pressure (BP) decreased in the ST group by - 4.4 +/- 6.7 % vs. 1.3 +/- 9.5 % (p < 0.05) compared to the controls after the ST period. Muscle strength as well as walking and stair-climbing times remained the same during the CRT. However, the changes in diastolic BP (- 8.9 +/- 8.7 % vs. - 1.0 +/- 6.6 %, p < 0.05) and fasting blood glucose concentrations (0.1 +/- 0.4 mmol/L vs. 0.3 +/- 0.4 mmol/L, p < 0.05) differed between the ST and control groups after the whole 42-week study period. Strength training has positive health effects in aging men by increasing maximal strength and functional performance and by decreasing resting blood pressure and high-intensity reduced strength training can maintain these health benefits.
Loss of muscle power due to normal aging has greater functional impact than loss of strength alone. The present study compared two resistance training programs, one aimed at enhancing muscle power and one at increasing muscle strength, on muscle function and functional performance in older adults.
Sixty-seven healthy, independent older adults (65-84 years) were randomized to a high-velocity varied resistance (HV), constant resistance (ST), or nontraining control (CO) group. Participants trained twice weekly for 24 weeks using six exercises. Dynamic and isometric muscle strength, muscle power, movement velocity, muscle endurance, and a battery of functional performance tasks were assessed. Secondary outcomes included body composition, quality of life, and balance confidence.
Muscle strength increased significantly (p <.001) and similarly in the training groups compared to controls (HV, 51.0 +/- 9.0%; ST, 48.3 +/- 6.8%; CO, 1.2 +/- 5.1%). Peak muscle power also increased with training (p <.05), with no difference between training groups. The change in peak power was 50.5 +/- 4.1%, 33.8 +/- 3.8%, and -2.5 +/- 3.9% in the HV, ST, and CO groups, respectively. Training also improved selected functional performance tasks in the HV and ST groups compared to controls (p <.05), and the HV group reported improved quality of life (p =.018).
Muscle power and muscle strength improved similarly using either resistance training protocol, and these changes were accompanied by improvements in several functional performance tasks. However, improvements in the HV group occurred with less total work performed per training session.
Although the negative effects of bed rest on muscle strength and muscle mass are well established, it still remains a challenge to identify effective methods to restore physical capacity of elderly patients recovering from hospitalization. The present study compared different training regimes with respect to muscle strength, muscle fiber size, muscle architecture, and stair walking power in elderly postoperative patients. Thirty-six patients (60-86 yr) scheduled for unilateral hip replacement surgery due to hip osteoarthritis were randomized to either 1) resistance training (RT: 3/wk x 12 wk), 2) electrical stimulation (ES: 1 h/day x 12 wk), or 3) standard rehabilitation (SR: 1 h/day x 12 wk). All measurements were performed at baseline, at 5 wk and 12 wk postsurgery. After 12 wk of resistance training, maximal dynamic muscle strength increased by 30% at 60 degrees /s (P < 0.05) and by 29% at 180 degrees /s (P < 0.05); muscle fiber area increased for type I (+17%, P < 0.05), type IIa (+37%, P < 0.05), and type IIx muscle fibers (+51%, P < 0.05); and muscle fiber pennation angle increased by 22% and muscle thickness increased by 15% (P < 0.05). Furthermore, stair walking power increased by 35% (P < 0.05) and was related to the increase in type II fiber area (r = 0.729, P < 0.05). In contrast, there was no increase in any measurement outcomes with electrical stimulation and standard rehabilitation. The present study is the first to demonstrate the effectiveness of resistance training to induce beneficial qualitative changes in muscle fiber morphology and muscle architecture in elderly postoperative patients. In contrast, rehabilitation regimes based on functional exercises and neuromuscular electrical stimulation had no effect. The present data emphasize the importance of resistance training in future rehabilitation programs for elderly individuals.
The purpose of this study was to compare the effects of a strength training-enhanced program and a traditional pulmonary rehabilitation (PR) program on functional fitness (FF) in older patients with chronic obstructive pulmonary disease (COPD), using the Senior Fitness Test. Twenty patients were recruited from an outpatient PR program. After completing baseline measures, including muscular strength and the Senior Fitness Test, patients were randomly assigned to the strength training program (TR+ST, n = 10) or traditional PR program (TR, n = 10). Patients completed 16 exercise sessions that were conducted twice a week for 8-10 weeks, after which patients repeated outcome measurements. Independent t tests were conducted to determine whether groups differed between measures. Both the TR+ST and TR groups improved on all FF measures. Moderate effect sizes were found for two of the FF measures when the groups were compared. The addition of strength training to PR may have a favorable impact on FF in older patients with COPD.
We conducted a 12-wk resistance training program in elderly women [mean age 69 +/- 1.0 (SE) yr] to determine whether increases in muscle strength are associated with changes in cross-sectional fiber area of the vastus lateralis muscle. Twenty-seven healthy women were randomly assigned to either a control or exercise group. The program was satisfactorily completed and adequate biopsy material obtained from 6 controls and 13 exercisers. After initial testing of baseline maximal strength, exercisers began a training regimen consisting of seven exercises that stressed primary muscle groups of the lower extremities. No active intervention was prescribed for the controls. Increases in muscle strength of the exercising subjects were significant compared with baseline values (28-115%) in all muscle groups. No significant strength changes were observed in the controls. Cross-sectional area of type II muscle fibers significantly increased in the exercisers (20.1 +/- 6.8%, P = 0.02) compared with baseline. In contrast, no significant change in type II fiber area was observed in the controls. No significant changes in type I fiber area were found in either group. We conclude that a program of resistance exercise can be safely carried out by elderly women, such a program significantly increases muscle strength, and such gains are due, at least in part, to muscle hypertrophy.
Objectives: To study the effects of eight weeks of supervised, low intensity resistance training (80% of 10 repetition maximum (10RM)) and eight weeks of detraining on muscle strength and blood lipid profiles in healthy, sedentary postmenopausal women.
Subjects: Fifteen postmenopausal women, aged 49–62 years, took part in the study. Subjects were assigned to either a control (n = 7) or training (n = 8) group. The training regimen consisted of three sets of eight repetitions of leg press, bench press, knee extension, knee flexion, and lat pull-down, three days a week at 80% of 10RM. Dynamic leg strength, 10RM, and blood lipid profiles (total cholesterol (TC), low and high density lipoprotein cholesterol (LDL-C, HDL-C), triglycerides, and very low density lipoprotein cholesterol (VLDL-C)) were measured at baseline, after eight weeks of training, and after a further eight weeks of detraining.
Results: Eight weeks of resistance training produced significant increases in knee extension ( F 1,13 = 12.60; p<0.01), bench press ( F 1,13 = 13.79; p<0.01), leg press ( F 1,13 = 15.65; p<0.01), and lat pull-down ( F 1,13 = 16.60; p<0.005) 10RM strength tests. Although 10RM strength decreased after eight weeks of detraining, the results remained significantly elevated from baseline measures. Eight weeks of training did not result in any significant alterations in blood lipid profiles, body composition, or dynamic isokinetic leg strength. There were no significant differences in any of the variables investigated over the 16 week period in the control group.
Conclusions: These data suggest that a short, low intensity resistance training programme produces substantial improvements in muscle strength. Training of this intensity and duration was not sufficient to produce significant alterations in blood lipid concentrations.
We conducted a 12-wk resistance training program in elderly women [mean age 69 +/- 1.0 (SE) yr] to determine whether increases in muscle strength are associated with changes in cross-sectional fiber area of the vastus lateralis muscle. Twenty-seven healthy women were randomly assigned to either a control or exercise group. The program was satisfactorily completed and adequate biopsy material obtained from 6 controls and 13 exercisers. After initial testing of baseline maximal strength, exercisers began a training regimen consisting of seven exercises that stressed primary muscle groups of the lower extremities. No active intervention was prescribed for the controls. Increases in muscle strength of the exercising subjects were significant compared with baseline values (28-115%) in all muscle groups. No significant strength changes were observed in the controls. Cross-sectional area of type II muscle fibers significantly increased in the exercisers (20.1 +/- 6.8%, P = 0.02) compared with baseline. In contrast, no significant change in type II fiber area was observed in the controls. No significant changes in type I fiber area were found in either group. We conclude that a program of resistance exercise can be safely carried out by elderly women, such a program significantly increases muscle strength, and such gains are due, at least in part, to muscle hypertrophy.
To determine the effects of 12 weeks of progressive resistance strength training on the isometric strength, explosive power, and selected functional abilities of healthy women aged 75 and over.
Subjects were matched for age and habitual physical activity and then randomly assigned into either a control or an exercise group.
The Muscle Function Laboratory, Royal Free Hospital School of Medicine, London.
Fifty-two healthy women were recruited through local and national newspapers. Five dropped out before and seven (4 exercisers and 3 controls) during the study. Pre- and posttraining measurements were obtained from 20 exercisers (median age 79.5, range 76 to 93 years) and 20 controls (median age 79.5, range 75 to 90 years).
Training comprised one supervised session (1 hour) at the Medical School and two unsupervised home sessions (supported by an exercise tape and booklet) per week for 12 weeks. The training stimulus was three sets of four to eight repetitions of each exercise, using rice bags (1-1.5 kg) or elastic tubing for resistance. The exercises were intended specifically to strengthen the muscles considered relevant for the functional tasks, but were not to mimic the functional measurements. No intervention was prescribed for the controls.
Pre- and posttraining measurements were made for isometric knee extensor strength (IKES), isometric elbow flexor strength (IEFS), handgrip strength (HGS), leg extensor power (LEP), and anthropometric indices (Body impedance analysis, arm muscle circumference, and body weight). Functional ability tests were chair rise, kneel rise, rise from lying on the floor, 118-m self-paced corridor walk, stair climbing, functional reach, stepping up, stepping down, and lifting weights onto a shelf. Pre- and posttraining comparisons were made using analysis of variance or analysis of covariance (using weight as a covariate) for normally distributed continuous data and one-sided Fishers exact test (2 x 2 table) for discontinuous data.
Improvements in IKES (mean change 27%, P = .03), IEFS (22%, P = .05), HGS (4%, P = .05), LEP/kg (18%, P = .05) were associated with training, but the improvement in LEP (18%, P = .11) did not reach statistical significance. There was an association between training and a reduction in normal pace kneel rise time (median change 21%, P = .02) and a small improvement in step up height (median 5%, P = .005). The other functional tests did not improve.
Progressive resistance exercise can produce substantial increases in muscle strength and in power standardized for body weight in healthy, very old women. However, isolated increases in strength and LEP/kg may confer only limited functional benefit in healthy, independent, very old women.
To determine whether a total body, heavy resistance, strength training (ST) program can significantly increase muscle strength and hypertrophy without muscle cell disruption and soreness in older men, 35 sedentary male subjects between the ages of 50 and 69 years of age (60 +/- 5, mean +/- SD) were studied. Twelve served as inactive controls. Muscular strength, cross-sectional muscle area, serum creatine kinase (CK) activity and perceived soreness were assessed before and after a 16 wk heavy resistance ST program. The ST program resulted in a 43% increase in muscular strength (p < 0.001), and a 7.2% increase in midthigh muscle area (153 +/- 24 vs 164 +/- 23 cm2, p < 0.001). There were no significant changes in strength or muscle area in the inactive control group. Peak serum CK levels were approximately twofold above baseline (278 +/- 175 vs 133 +/- 88 U/l, p < 0.01) 8 h after the first regular training session. At the end of training, the peak rise in CK levels was also reached 8 h after exercise, but was reduced substantially at the same absolute (p < 0.01) and relative resistance loads (p < 0.01) compared to the first training session. Muscle soreness after exercise was only occasionally reported at the beginning of training and was almost nonexistent after training. These results indicate that middle-aged and older men can safely participate in a total body strength training program, intense enough to produce substantial increases in muscle strength and hypertrophy, without promoting muscle soreness or significant muscle cell disruption.(ABSTRACT TRUNCATED AT 250 WORDS)
We studied the effects of Eurycoma longifolia Jack, commonly known as Tongkat Ali in Malaysia, on the initiation of sexual performance and the weights of sexual accessories in inexperienced castrated male rats. The doses of 200, 400 and 800 mg/kg body weight, which were extracted from E. longifolia Jack, were orally administered to the rats twice daily for 10 days prior to the tests and continued throughout the test period. Testosterone was used as a positive control after injecting 15 mg/kg daily subcutaneously for 32 days. Results showed that E. longifolia Jack produced a dose-dependent increase in sexual performance of the treated animals, but the E. longifolia Jack groups showed lower sexual performance in mounting, intromission and ejaculation than the testosterone group. Further results also showed that E. longifolia Jack promoted the growth of both ventral prostate and seminal vesicles as compared with the control, but the growth of sexual accessories at 800 mg/kg of butanol, methanol, water and chloroform fractions of E. longifolia Jack was less than that of testosterone treated group. The present study therefore gives further evidence of the folkuse of E. longifolia as an aphrodisiac.
To evaluate the effects of a progressive resistance strength training program on changes in muscle strength, gait, and balance in older individuals 1 yr after stroke, seven individuals were recruited who were greater than 60-yr-old, 1 yr after stroke, living at home, and able to follow verbal commands.
Subjects participated in a 12-wk 2x per wk resistance training program at 70% of 1 repetition maximum.
Lower limb strength improved 68% on the affected side and 48% on the intact side during training, with the largest increases observed for hip extension (affected side: 88%, P < 0.01; intact side: 103%, P < 0.001). Repeated chair stand time decreased 21% (P < 0.02). Motor performance assessed by the Motor Assessment Scale improved 9% (P < 0.04) and static and dynamic balance (Berg balance scale) improved 12% (P < 0.004). Progressive resistance training in individuals 1 yr after stroke improves affected and intact side lower limb strength and was associated with gains in chair stand time, balance, and motor performance.
These results support the concept that strength training is an appropriate intervention to improve the quality of physical function in older community dwelling stroke survivors.
Muscle size and strength decrease with aging, and the resultant muscle weakness has been implicated in increased risk of falls in older adults. These falls have large economic and functional costs.
The purpose of this randomized, controlled study was to determine if an 8-week, 3-day per week intense (77.8 +/- 3.4% of 1-repetition maximum [1RM]) strength training program could improve functional ability related to the risk of falling in subjects aged 61--87 years (mean 72, SD 6.3). Twelve strength-training-naive subjects performed two sets of 10 repetitions for six lower body exercises while 12 subjects served as nonintervention controls. Subjects were tested pre-, mid-, and postintervention for strength gain and on three tests of functional ability.
Postintervention strength was significantly better (p <.017) in all training subjects across all exercises, and no injuries were reported as a result of either training or 1RM testing. After controlling for preintervention differences, repeated measure analysis of covariance (ANCOVA) found a significant difference between experimental and nonintervention control subjects for postintervention maximal walking speed [F(1,19) = 5.03, p <.05]. There were no significant between-group differences for 1-leg blind balance time or 5-repetition sit-to-stand performance [F(1,19) =.082; F(1,19) =.068, respectively, p >.05].
These findings suggest that strength training alone does not appear to enhance standing balance or sit-to-stand performance in active, community-dwelling older adults but that it may improve maximal walking speed. The relationship between strength gain and risk of falls remains unclear. The data do reinforce the notion that intense strength training is a safe and effective way to increase muscle strength in this population.
To test the efficacy of high-velocity training in healthy older persons.
A 12-week randomized trial, with subjects blocked for gender and residence, comparing high-velocity resistance training with a self-paced walking program.
Retirement community.
Forty-three volunteers over the age of 70 years.
Power group: high-velocity leg exercises 3 times weekly with weekly increases in resistance combined with 45 minutes of moderate, nonresistance exercise weekly. Walking group: moderate intensity exercise 30 minutes daily, 6 days weekly.
Variables measured included leg press peak power and leg extensor strength. Functional performance outcomes included: 6-minute walk distance, Short Physical Performance Battery, Physical Performance Test, and Medical Outcomes Study Short-Form Health Survey.
Peak power improved 22% (p =.004) in the power group (3.7 +/- 1.0 W/kg to 4.5 +/- 1.4 W/kg) but did not change in the walking group (3.99 +/-.76 W/kg to 3.65 +/-.94 W/kg). Leg extensor power at resistance of 50%, 60%, and 70% of body weight increased 50%, 77%, and 141%, respectively, in the power group (p <.0001, repeated-measures analysis of variance). Strength improved 22% in the power-trained individuals and 12% in the walkers (p <.0001). Training did not improve functional task performance in either group. One subject developed a radiculopathy during training.
Resistance training focusing on speed of movement improved leg power and maximal strength substantially, but did not improve functional performance in healthy high-functioning older volunteers.
To examine the relationship between diabetes and the incidence of functional disability and to determine the predictors of functional disability among older women with diabetes.
We analyzed data from 8,344 women enrolled in the Study of Osteoporotic Fractures, a prospective cohort of women aged > or =65 years. Diabetes (n = 527, 6.3% prevalence) and comorbidities (coronary heart disease, stroke, arthritis, depression, and visual impairment) were assessed by questionnaire and physical examination. Incident disability, defined as onset of inability to do one or more major functional tasks (walking 0.25 mile, climbing 10 steps, performing household chores, shopping, and cooking meals), was assessed by questionnaire over 12 years.
The yearly incidence of any functional disability was 9.8% among women with diabetes and 4.8% among women without diabetes. The age-adjusted hazard rate ratio (HRR) of disability for specific tasks associated with diabetes ranged from 2.12 (1.82-2.48) for doing housework to 2.50 (2.05-3.04) for walking two to three blocks. After adjustment for potential confounders at baseline (BMI, physical activity, estrogen use, baseline functional status, visual impairment, and marital status) and comorbidities (heart disease, stroke, depression, and arthritis), diabetes remained associated with a 42% increased risk of any incident disability and a 53-98% increased risk of disability for specific tasks. Among women with diabetes, older age, higher BMI, coronary heart disease, arthritis, physical inactivity, and severe visual impairment at baseline were each independently associated with disability.
Diabetes is associated with an increased incidence of functional disability, which is likely to further erode health status and quality of life.
to determine the effects of aerobic training on the maximal aerobic power of healthy, very elderly people.
a 12-week control period followed by 24 weeks of progressive, weight bearing, aerobic training.
26 men and women aged 79 to 91 years conforming to pre-determined health criteria.
we took measurements before and after a 12 week control period and following 24 weeks of training. These were maximal aerobic power (VO(2)max), heart rate at an oxygen consumption of 10 ml x kg(-1) x min(-1) (HR at VO(2)10), resting heart rate, isometric knee extensor strength, isometric elbow flexor strength and lower limb extensor power.
pre-control values of VO(2)max for the women and men were 14.1 (SD 2.79) and 22.0 (5.12) ml.kg(-1).min(-1) respectively. There was no significant change in the VO(2)max of either group over the control period. After training, there was a 15% increase in the VO(2)max of the women (P<0.01) but no change was observed in the men. In the women, there was no significant change in HR at VO(2)10 over the control period but a 14% decrease (P<0.01) after training. In the men there was a 7% (P<0.05) increase in HR at VO(2)10 over the control period and a 5% (P<0.05) decrease after training. No effect of training was seen on isometric knee extensor strength, isometric elbow flexor strength or lower limb extensor power of either group.
progressive aerobic training can increase the maximal aerobic power of very elderly women. A 15% increase in VO(2)max may prevent many elderly women from crossing functionally important thresholds, thereby helping to maintain independence.
This study investigated the effect of strength training on the mechanical properties of the human patella tendon of older individuals. Subjects were assigned to training (n = 9; age 74.3 +/- 3.5 years, body mass 69.7 +/- 14.8 kg and height 163.4 +/- 9.1 cm, mean +/- S.D.) and control (n = 9; age 67.1 +/- 2 years, body mass 73.5 +/- 14.9 kg and height 168.3 +/- 11.5 cm) groups. Strength training (two series of 10 repetitions at 80 % of five-repetition maximum) was performed three times per week for 14 weeks using leg extension and leg press exercises. Measurements of tendon elongation during a ramp isometric knee extension were performed before and after training and control periods in vivo using ultrasonography. Training caused a decreased tendon elongation and strain at all levels of force and stress (P < 0.01). Baseline tendon elongation and strain at maximal tendon load were 4.7 +/- 1.1 mm and 9.9 +/- 2.2 %, respectively (maximum force: 3346 +/- 1168 N; maximum stress: 40 +/- 11 MPa). After training, these values decreased to 2.9 +/- 1.2 mm and 5.9 +/- 2.4 % (P < 0.01), respectively (maximum force: 3555 +/- 1257 N; maximum stress: 42 +/- 11 MPa). Tendon stiffness increased by 65 % (2187 +/- 713 to 3609 +/- 1220 N mm-1; P < 0.05) and Young's modulus increased by 69 % (1.3 +/- 0.3 to 2.2 +/- 0.8 GPa; P < 0.01). As a result of these changes, the rate of torque development increased by 27 % (482.8 +/- 302.5 to 612.6 +/- 401 N m s-1; P < 0.01) following training. No significant changes occurred in any measured variables in the control group (P > 0.05). This study shows for the first time that strength training in old age increases the stiffness and Young's modulus of human tendons. This may reduce the risk of tendon injury in old age and has implications for contractile force production and the rapid execution of motor tasks.
The effect of increasing doses of various fractions of Eurycoma longifolia Jack extracts on libido was examined in middle-aged male rats. The results showed that a high dose (800 mg/kg) of all E. longifolia Jack extracts significantly increased mount frequency (MF) (P < 0.05) over that of untreated controls, but had no effect on the frequency of intromission or ejaculation. Methanol, chloroform, water, and butanol fractions exhibited MF of 2.5 +/- 0.1, 2.6 +/- 0.3, 2.5 +/- 0.1 and 2.6 +/- 0.2, respectively, in adult, middle-aged male rats, and retired breeders versus 2.3 +/- 0.1 in untreated controls. This translated to a minor increase in MF of 8.7%, 13.0%, 8.7%, and 13.0% for these fractions, respectively, during the 20-minute observation period. The results of this study show that E. longifolia Jack extracts can increase libido in middle-aged male rats.
Eurycoma longifolia Jack was investigated for sexual motivation activity in adult, middle-aged male mice and in retired breeders, using the modified open field and the modified runway choice methods. Each mouse received 500 mg/kg of one of 4 fractions of E. longifolia Jack, viz. chloroform, methanol, butanol, and water, whereas the mice in the control and yohimbine groups received 3 ml/kg of normal saline and 30 mg/kg of yohimbine daily respectively for 10 d. The results show a transient increase in the percentage of male mice responding to the right choice after chronic consumption of the fractions with 50 percent of the adult middle-aged male mice treated with E. longifolia Jack and yohimbine scoring the right choice after 8 and 5 days post-treatment respectively. In conclusion, this study has shown that E. longifolia Jack continues to enhance sexual motivation in adult, middle-aged male mice and in retired breeders.
Screening of aqueous extract of Phyllantus niruri (PL), Zingiber zerumbet (ZG), Eurycoma longifolia (TA-a and TA-b) and Andrographis paniculata (AP) to determine their blood glucose lowering effect were conducted in normoglycaemic and Streptozotocin-induced hyperglycaemic rats. Significant reduction in blood glucose level at 52.90% was shown when hyperglycaemic rats were treated with 50 mg/kg body weight (BW) aqueous extract of AP. This effect is enhanced when freeze-dried material was used, where 6.25 mg/kg BW gave 61.81% reduction in blood glucose level. In the administration of TA-a and TA-b, positive results in hyperglyacaemic rats were only obtained when 150 mg/kg BW of the aqueous extract was used. No significant reduction in blood glucose level were shown in hyperglycaemic rats treated with PL and ZG at all concentrations used (50, 100 and 150 mg/kg BW). In normoglycaemic rats, no significant reduction was noted when all the same extracts were used.
The age-related loss of muscle power in older adults is greater than that of muscle strength and is associated with a decline in physical performance.
To investigate the effects of a short-term high-velocity varied resistance training programme on physical performance in healthy community-dwelling adults aged 60-80 years.
Subjects undertook exercise (EX; n=15) or maintained customary activity (controls, CON; n=10) for 8 weeks. The EX group trained 2 days/week using machine weights for three sets of eight repetitions at 35, 55, and 75% of their one-repetition maximum (the maximal weight that an individual can lift once with acceptable form) for seven upper- and lower-body exercises using explosive concentric movements.
Fourteen EX and 10 CON subjects completed the study. Dynamic muscle strength significantly increased (p=0.001) in the EX group for all exercises (from 21.4 +/- 9.6 to 82.0 +/- 59.2%, mean +/- SD) following training, as did knee extension power (p <0.01). Significant improvement occurred for the EX group in the floor rise to standing (10.4 +/- 11.5%, p=0.004), usual 6-metre walk (6.6 +/- 8.2%, p=0.010), repeated chair rise (10.4 +/- 15.6%, p=0.013), and lift and reach (25.6 +/- 12.1%, p=0.002) performance tasks but not in the CON group.
Progressive resistance training that incorporates rapid rate-of-force development movements may be safely undertaken in healthy older adults and results in significant gains in muscle strength, muscle power, and physical performance. Such improvements could prolong functional independence and improve the quality of life.
To evaluate the influence of a twice-weekly progressive resistance training (PRT) program, without a concomitant weight loss diet, on abdominal fat and insulin sensitivity in older men with type 2 diabetes.
Nine older men (aged 66.6 +/- 3.1) with type 2 diabetes participated in a 16-week PRT supervised program (50-80% of the one repetition maximum), for all main muscle groups. Basal glycemia, HbA(1c), diet, habitual physical activity, body composition, and upper/lower maximal strength were measured. Insulin sensitivity was determined according to Bergman's minimal model procedure and abdominal fat was obtained by computed tomography. The measurements were taken 4 weeks before training (-4), immediately before training (0), and at 8-week intervals (i.e., weeks 8 and 16) during the 16-week training period.
No significant variation was observed in any of the above selected parameters during the 4-week control period. After PRT, both leg and arm maximal strength increased significantly by 17.1 and 18.2%, respectively. Visceral and subcutaneous abdominal fat decreased significantly by 10.3% (from 249.5 +/- 97.9 to 225.6 +/- 96.6 cm(3), P < 0.01) and by 11.2% (from 356.0 +/- 127.5 to 308.6 +/- 118.8 cm(3), P < 0.01), respectively, while no changes were observed in body mass. PRT significantly increased insulin sensitivity by 46.3% (from 2.0 +/- 1.2 to 2.8 +/- 1.6 . 10(4) . min(-1) . muU(-1) . ml(-1), P < 0.01), whereas it significantly decreased (-7.1%, P < 0.05) fasting blood glucose (from 146.6 +/- 28.3 to 135.0 +/- 29.3 mg/dl). Finally, a 15.5% increase in energy intake (from 2,287.1 +/- 354.7 to 2,619.0 +/- 472.1 kcal/day, P < 0.05) was observed.
Two sessions per week of PRT, without a concomitant weight loss diet, significantly improves insulin sensitivity and fasting glycemia and decreases abdominal fat in older men with type 2 diabetes.
Eurycoma longifolia Jack commonly known as Tongkat Ali in Malaysia, has been used in Malaysia to increase male virility and sexual prowess. The objective of this study is to evaluate sexual arousal in sexually sluggish old male rats, 24 months old and retired breeders, receiving 200, 400, or 800 mg/kg of various fractions of E. longifolia Jack, twice daily, for 10 days. Control rats received 3 ml/kg of normal saline. The aphrodisiac effect was monitored by the act of yawning and stretching because yawning, either alone or associated with stretching, is considered an ancestral vestige surviving throughout evolution that promotes sexual arousal. The results showed that 800 mg/kg of E. longifolia Jack increased yawning by 50% and stretching by 16.7% in sexually sluggish old male rats, by 676-719% and 31-336%, respectively, in sexually active male rats, and by 22-44% and 75-100%, respectively, in middle aged, 9 months old and retired breeders. We conclude that the results of this study support the folk use of this plant as an aphrodisiac.
The timing of the menopause transition has remained fairly constant throughout history. It represents a milestone in female health and, after passing through it, women experience increased musculoskeletal and cardiovascular morbidity. Muscle performance is an important determinant of functional capacity and quality of life among the elderly and is also involved in the maintenance of balance. Therefore, good muscle strength can prevent fragility fractures and lessen the burden of osteoporosis. Muscle strength begins to decline during the perimenopausal years and this phenomenon seems to be partly estrogen dependent. Randomized controlled trials have indicated that hormone replacement therapy may prevent a decline in muscle performance, although the exact mechanism of estrogen-dependent sarcopenia remains to be clarified. Exercises have been shown to improve postmenopausal muscle performance and hormone replacement therapy may also potentiate these beneficial effects. Improvement or maintenance of muscle strength alone, however, may not be considered as a primary indication for long-term hormone replacement therapy in view of current knowledge of its risks and benefits. Work history and educational background may be associated with postmenopausal muscle performance, which itself has unique associations with skeletal and cardiovascular diseases.
Changes in the hormonal milieu at the menopause are associated with an increase in total adiposity and a more android pattern of fat distribution, with the latter associated with an increased risk of the metabolic syndrome. The aim of this study was to explore potential mechanisms that might contribute to the changes in body composition associated with the menopause transition.
Using real-time PCR analysis, we have compared the expression of various factors involved in fat metabolism in subcutaneous abdominal and gluteal fat in premenopausal (Group 1; n=11), postmenopausal (Group 2; n=10) and postmenopausal women taking estrogen therapy (Group 3; n=10).
All subjects were of normal body mass index, euglycemic and normolipemic. The postmenopausal women were older (Group 1, 43.1+5.0 versus Groups 2 and 3, 57.9+/-7.4 years, P<0.001 and 56.1+/-4.5 years, P<0.001, respectively). Expression analysis revealed that levels of transcripts encoding adiponectin, peroxisome proliferator-activated receptor gamma and fatty acid transporter, each associated with insulin sensitivity, were significantly greater in gluteal fat from estrogen deplete postmenopausal women than in fat from the other two groups (P<0.05). In contrast, levels of transcripts for acetyl CoA carboxylase alpha, long chain acyl CoA dehydrogenase and hormone sensitive lipase were significantly greater in abdominal fat from premenopausal women than either postmenopausal groups (P<0.05).
These findings indicate both aging and the menopause transition are associated with changes in fat metabolism, which may contribute to the accumulation of body fat after menopause.
To determine whether variation in resistance exercise volume affects muscle function and physical performance response in older adults.
A randomized trial with subjects assigned to a single-set (1-SET) or three-set (3-SET) exercise group.
An exercise facility at the University of Queensland.
Twenty-eight community-dwelling men and women aged 65 to 78.
Progressive resistance training consisting of seven exercises targeting the major muscle groups of the upper and lower body performed on exercise machines twice weekly for 20 weeks at eight-repetition maximum (RM) intensity.
Muscle function included isotonic muscle strength (1-RM) of the seven exercises, isokinetic and isometric knee extensor strength, and muscle endurance for the chest press and leg press exercises. Physical performance included timed chair rise, usual and fast 6-m walk, 6-m backwards walk, 400-m walk, floor rise to standing, and stair climbing ability. In addition, body composition was determined using dual energy x-ray absorptiometry.
Isotonic muscle strength increased in both exercise groups for all seven exercises (P<.01), with the gain in the 3-SET group greater (P<.05) for the seated row, triceps extension, and knee extension (analysis of covariance). Similarly, muscle endurance gains were greater for the 3-SET than the 1-SET group (P<.01), with no significant difference between groups for isokinetic and isometric knee extensor strength. Both groups improved (P<.05) in the chair rise (1-SET, 10.1%; 3-SET, 13.6%), 6-m backwards walk (1-SET, 14.3%; 3-SET, 14.8%), 400-m walk (1-SET, 3.8%; 3-SET, 7.4%), and stair climbing test (1-SET, 7.7%; 3-SET, 6.4%), with the only difference between groups for the 400-m walk (P<.05). There was no difference between groups for change in body composition.
Resistance training consisting of only single-set exercises is sufficient to significantly enhance muscle function and physical performance, although muscle strength and endurance gains are greater with higher-volume work. These findings have application in designing time-efficient exercise regimens to enhance neuromuscular function in older adults.
Adequate skeletal muscle strength is essential for physical functioning and low muscle strength is a predictor of physical limitations. Older adults with diabetes have a two- to threefold increased risk of physical disability. However, muscle strength has never been investigated with regard to diabetes in a population-based study. We evaluated grip and knee extensor strength and muscle mass in 485 older adults with diabetes and 2,133 without diabetes in the Health, Aging, and Body Composition study. Older adults with diabetes had greater arm and leg muscle mass than those without diabetes because they were bigger in body size. Despite this, muscle strength was lower in men with diabetes and not higher in women with diabetes than corresponding counterparts. Muscle quality, defined as muscle strength per unit regional muscle mass, was significantly lower in men and women with diabetes than those without diabetes in both upper and lower extremities. Furthermore, longer duration of diabetes (>or=6 years) and poor glycemic control (HbA(1c) >8.0%) were associated with even poorer muscle quality. In conclusion, diabetes is associated with lower skeletal muscle strength and quality. These characteristics may contribute to the development of physical disability in older adults with diabetes.
Strength versus muscle power-specific resistance training in community-dwelling older adults
- Tr Henwood
- Rick S Taafe
The ergogenic effects of Eurycoma longifolia Jack: a pilot study Joint conference of BASEM and BASES
- H Sareena
- Y Ashril
Single versus multiset effects on physical performance and body composition
- D A Galvao
- D R Taafe
- DA Galvao