PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Strength training”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

Neuromuscular adaptation during prolonged strength training, detraining and re-strength-training in middle-aged and elderly people.

Effects of a 24-week strength training performed twice weekly (24 ST) (combined with explosive exercises) followed by either a 3-week detraining (3 DT) and a 21-week re-strength-training (21 RST) (experiment A) or by a 24-week detraining (24 DT) (experiment B) on neural activation of the agonist and antagonist leg extensors, muscle cross-sectional area (CSA) of the quadriceps femoris, maximal isometric and one repetition maximum (1-RM) strength and jumping (J) and walking (W) performances were examined. A group of middle-aged (M, 37-44 years, n = 12) and elderly (E, 62-77, n = 10) and another group of M (35-45, n = 7) and E (63-78, n = 7) served as subjects. In experiment A, the 1-RM increased substantially during 24 ST in M (27%, P<0.001) and E (29%, P<0.001) and in experiment B in M (29%, P<0.001) and E (23%, P<0.01). During 21 RST the 1-RM was increased by 5% at week 48 (P<0.01) in M and 3% at week 41 in E (n.s., but P<0.05 at week 34). In experiment A the integrated electromyogram (IEMG) of the vastus muscles in the 1-RM increased during 24 ST in both M (P<0.05) and E (P<0.001) and during 21 RST in M for the right (P<0.05) and in E for both legs (P<0.05). The biceps femoris co-activation during the 1-RM leg extension decreased during the first 8-week training in M (from 29+/-5% to 25+/-3%, n.s.) and especially in E (from 41+/-11% to 32+/-9%, P<0.05). The CSA increased by 7% in M (P<0.05) and by 7% in E (P<0.001), and by 7% (n.s.) in M and by 3% in E (n.s.) during 24 ST periods. Increases of 18% (P<0.001) and 12% (P<0.05) in M and 22% (P<0.001) and 26% (P<0.05) in E occurred in J. W speed increased (P<0.05) in both age groups. The only decrease during 3 DT was in maximal isometric force in M by 6% (P<0.05) and by 4% (n.s.) in E. During 24 DT the CSA decreased in both age groups (P<0.01), the 1-RM decreased by 6% (P<0.05) in M and by 4% (P<0.05) in E and isometric force by 12% (P<0.001) in M and by 9% (P<0.05) in E, respectively, while J and W remained unaltered. The strength gains were accompanied by increased maximal voluntary neural activation of the agonists in both age groups with reduced antagonist co-activation in the elderly during the initial training phases. Neural adaptation seemed to play a greater role than muscle hypertrophy. Short-term detraining led to only minor changes, while prolonged detraining resulted in muscle atrophy and decreased voluntary strength, but explosive jumping and walking actions in both age groups appeared to remain elevated for quite a long time by compensatory types of physical activities when performed on a regular basis.

Adaptation, Physiological↗

Effects of strength training on muscle strength, cross-sectional area, maximal electromyographic activity, and serum hormones in premenopausal women with fibromyalgia.

OBJECTIVE: To examine the effects of strength training on basal concentrations and acute responses of serum hormones, and their possible interrelationships with training induced muscle hypertrophy and strength gains of the knee extensor muscles in women with fibromyalgia (FM) and healthy controls. METHODS: Twenty-one premenopausal women with FM were randomized to 21 week strength training (FMT; n = 11) or control (FMC; n = 10) groups. Twelve premenopausal sedentary healthy women served as controls (HC). Surface electromyographic (EMG) activity, maximal unilateral isometric force of the right knee extensors, and muscle cross-sectional area (CSA) of the quadriceps femoris throughout the lengths of 3/12 to 12/15 of the femur (Lf) were measured. Serum concentrations of total and free testosterone and growth hormone (GH) were analyzed at rest and in pre- and post-exercise conditions, while levels of insulin-like growth factor and dehydroepiandrosterone sulfate were measured at rest only. RESULTS: Mean (SD) maximal force increased by 18% (10%) (p < 0.001) in the FMT group, and by 22% (12%) (p < 0.001) in the HC, while in the FMC it remained unchanged. Maximum integrated EMG of the agonists (VL + VM/2) increased in HC by 22% (p < 0.05) and in the FMT by 19% (p < 0.05). Significant increases in the CSA of the QF were observed at 5 to 12/15 Lf in FMT (p < 0.05-0.01) and at 3 to 12/15 Lf in HC (p < 0.05-0.001), while in FMC the CSA remained unchanged. No training induced changes occurred in the basal concentrations of serum hormones examined. A significant acute increase took place in the mean concentration of GH at pre-training in HC (p < 0.01) and in the FMT (p < 0.05), while at post-training the elevations after the loading (p < 0.001 and 0.05) remained elevated up to 15 min (p < 0.05) in HC and up to 30 min (p < 0.01) post-loading in the FMT. CONCLUSION: Both the magnitude and time course of adaptations of the neuromuscular system to resistance training in women with FM were completely comparable to those taking place in healthy women. Basal levels of the anabolic hormones seem to be similar in women with FM compared to age matched healthy women. Observations recorded during the acute loading conditions might be considered an indication of the training induced adaptation of the endocrine system, showing that the acute GH response may become systematic after strength training in both women with FM and controls.

Adult↗

Task-oriented progressive resistance strength training improves muscle strength and functional performance in individuals with stroke.

OBJECTIVE: To examine the effectiveness of task-oriented progressive resistance strength training on lower extremity strength and functional performance in chronic stroke subjects. DESIGN: Single-blind, randomized controlled trial. SETTING: Medical centre and district hospital. SUBJECTS: Forty-eight subjects at least one year post stroke. INTERVENTIONS: Participants randomly allocated to two groups, control (n-/24) and experimental (n-/24). Subjects in the control group did not receive any rehabilitation training. Subjects in the experimental group were put on a four-week task-oriented progressive resistance strength training. MAIN MEASURES: Lower extremity muscle strength, gait velocity, cadence, stride length, six-minute walk test, step test, and timed up and go test. RESULTS: Muscle strength significantly improved in the experimental group for strong side muscle groups (ranged from 23.9% to 36.5%) and paretic side muscle groups (ranged from 10.1% to 77.9%). In the control group muscle strength changes ranged from 6.7% gain to 11.2% decline. The experimental group showed significant improvement in all selected measures of functional performance except for the step test. In the control group, the number of repetitions of the step test significantly decreased (-20.3%) with no change in other functional tests. There was a significant difference between groups for muscle strength and all functional measures. The strength gain was significantly associated with gain in the functional tests. CONCLUSIONS: The task-oriented progressive resistance strength training programme could improve lower extremity muscle strength in individuals with chronic stroke and could carry over into improvement in functional abilities.

Aged↗

The effects of strength training on strength and health-related quality of life in older adult women.

The short-term effects of an accessible exercise intervention on the strength and health-related quality of life (HRQOL) among older adult women were evaluated. We conducted an 8-week resistance training intervention utilizing elastic bands in 62 community-dwelling women with a mean age of 68 years. Participants were randomly assigned to either an exercise or a control group. Pre- and postintervention assessments included strength tests and HRQOL. Results revealed significant increases in three major muscles compared to the control group. However, there were no significant changes on either mental or physical health functioning. The elastic bands provide older adult women with an inexpensive, practical exercise program that effectively increases strength within 8 weeks but may have little effect on self-reported HRQOL.

Aged↗

Serum free testosterone, leptin and soluble leptin receptor changes in a 6-week strength-training programme.

Strength training is usually associated with a reduction in fat mass and with muscle hypertrophy. The aim of the present study was to examine whether the serum free leptin index (FLI), measured by the molar excess of soluble leptin receptor (sOB-R) over leptin, is increased by 6 weeks of strength training. Eighteen male, physical education students were randomly assigned to two groups: a strength-training (n 12) and a control group (n 6). Body composition (lean body mass and body fat) determined by dual-energy X-ray absorptiometry (DXA), muscle performance and leptin, sOB-R, total testosterone and free testosterone concentrations were determined before and after training. Fat mass was reduced by 1 kg with strength training (P<0.05). Lean body mass of trained extremities was increased by 3% (P<0.05), while the concentration of free testosterone in serum was reduced by 17% (P<0.05) after training. However, despite the reduction in fat mass and free testosterone, serum leptin concentration was not significantly affected by strength training, even after accounting for the differences in body fat. By contrast, for a given fat mass, the sOB-R was increased by 13% (P<0.05) at the end of the strength-training programme, although the molar excess of sOB-R over leptin remained unchanged. Therefore, the quantity of free leptin available to bind to the target tissues was not significantly affected by the short strength-training programme, which elicited a 7% reduction in fat mass.

Absorptiometry, Photon↗

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

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

Exercise↗

[Sarcopenia and strength training. Age-related changes: effect of strength training].

Sarcopenia signifies the age-related loss of muscle mass and consequently muscle strength. Sarcopenia appears to be caused by both muscular and neural factors. Concurrently with the muscle atrophy, a non-linear loss of muscle strength is observed. The decline accelerates after the age of 60. The ability to produce muscular power is reduced even more than the muscle strength. Strength training increases muscle strength and muscular power in the elderly thus counteracting part of the age-related reduction. Improvements, however, depend on the initial strength in the elderly person. The benefit of strength training is greatest in frail elderly and the oldest old, although elderly in general could benefit from strength training. Considering the growing section of elderly in the population, the focus on sarcopenia and measures to counteract this seems more relevant than ever.

Aged↗

The effects of a 12-week strength-training program on strength and functionality in women with fibromyalgia.

OBJECTIVE: To determine whether women with fibromyalgia benefit from strength training. DESIGN: Randomized controlled trial. SETTING: Testing was completed at the university and training was completed at a local community wellness facility. PARTICIPANTS: Twenty-nine women (age range, 18-54 y) with fibromyalgia participated. Subjects were randomly assigned to a control (n=14; wait-listed for exercise) or strength (n=15) group. After the first 4 weeks, 7 (47%) women dropped from the strength group. INTERVENTION: Subjects underwent 12 weeks of training on 11 exercises, 2 times a week, performing 1 set of 8 to 12 repetitions at 40% to 60% of their maximal lifts and were progressed to 60% to 80%. MAIN OUTCOME MEASURES: Subjects were measured for strength, functionality, tender point sensitivity, and fibromyalgia impact. RESULTS: The strength group significantly (P< or =.05) improved upper- (strength, 39+/-11 to 42+/-12 kg; control, 38+/-13 to 38+/-12 kg) and lower- (strength, 68+/-28 to 82+/-25 kg; control, 61+/-25 to 61+/-26 kg) body strength. Upper-body functionality measured by the Continuous-Scale Physical Functional Performance test improved significantly (strength, 44+/-11 to 50+/-16U; control, 51+/-11 to 49+/-13U) after training. Tender point sensitivity and fibromyalgia impact did not change. CONCLUSIONS: Strength training improved strength and some functionality in women with fibromyalgia. Interventions with resistance have important implications on independence and quality of life issues for women with fibromyalgia.

Activities of Daily Living↗

Left ventricular long-axis diastolic function is augmented in the hearts of endurance-trained compared with strength-trained athletes.

In order to determine left ventricular global and regional myocardial functional reserve in endurance-trained and strength-trained athletes, and to identify predictors of exercise capacity, we studied 18 endurance-trained and 11 strength-trained athletes with left ventricular hypertrophy (172+/-27 and 188+/-39 g/m(2) respectively), and compared them with 14 sedentary controls. Global systolic (ejection fraction) and diastolic (transmitral flow) function, and regional longitudinal and transverse myocardial velocities [tissue Doppler echocardiography (TDE)], were measured at rest and immediately after exercise. In endurance-trained compared with strength-trained athletes, resting heart rate was lower (59+/-11 and 76+/-9 beats/min respectively; P<0.001), and the increase at peak exercise was greater (+211% and +139% respectively; P<0.001). In addition, exercise duration, workload, maximal oxygen consumption and global systolic functional reserve (but not peak ejection fraction) were higher in the endurance-trained athletes, and resting global diastolic function (E/A ratio 1.62+/-0.40 compared with 1.18+/-0.23; P<0.01) (where E-wave is peak velocity of early-diastolic mitral inflow and A-wave is peak velocity of mitral inflow during atrial contraction) and long-axis diastolic velocities (E(TDE)/A(TDE) ratio 2.2+/-1.2 compared with 1.1+/-0.3; P<0.01) (where E(TDE) and A(TDE) represent peak early- and late-diastolic myocardial or tissue velocity respectively) were augmented. Systolic velocities were similar. Exercise capacity was best predicted from end-diastolic diameter index and E/A ratio at rest, and end-diastolic volume index and diastolic longitudinal velocity during exercise (r=0.74, n=43, P<0.001). In conclusion, endurance-trained athletes had higher left ventricular long-axis diastolic velocities, augmented global early diastolic filling, and greater chronotropic and global systolic functional reserve. Maximal oxygen consumption was determined by diastolic loading and early relaxation rather than by systolic function, suggesting that dynamic exercise training improves cardiac performance by an effect on diastolic filling.

Adult↗

Change in self-efficacy following a single strength training session predicts sedentary older adults' subsequent motivation to join a strength training program.

PURPOSE: To determine whether performance accomplishment and perceived exertion predict change in self-efficacy following a single strength training session and whether change in self-efficacy predicts subsequent motivation to join a strength training program. METHODS: Fifty-nine sedentary older adults participated in a single strength training session at a seniors' exercise center, completed measures of perceived exertion and self-efficacy, and received a voucher for a free fitness consultation. RESULTS: Regression analyses indicated that perceived exertion predicted change in self-efficacy. In turn, greater change in self-efficacy was associated with a greater likelihood of using the voucher for a fitness consultation. DISCUSSION: Sedentary older adults can be motivated toward joining a strength training program after an initial strength training session that required low exertion. Practitioners could increase strength training initiation by providing such experiences.

Aged↗

Rehabilitation of neck-shoulder pain in women industrial workers: a randomized trial comparing isometric shoulder endurance training with isometric shoulder strength training.

OBJECTIVES: To study whether isometric shoulder endurance was more advantageous than isometric shoulder strength training in reducing pain and perceived exertion and to increase shoulder function through improved muscle endurance and strength. DESIGN: Randomized trial. SETTING: Three occupational health care centers. PARTICIPANTS: Women industrial workers with nonspecific neck-shoulder pain. The International Classification of Diseases, 10th Revision (ICD-10) diagnosis was "cervicobrachial syndrome" (M53.1). Thirty-eight patients completed the isometric shoulder endurance training and 31 patients completed the isometric shoulder strength training. INTERVENTION: Twelve weeks of training. MAIN OUTCOME MEASURES: Self-reported pain and rating of perceived exertion (RPE), arm motion performance test, shoulder muscle strength, shoulder muscle endurance, and shoulder functional tests, as well as follow-up after supervised training had ended. RESULTS: The isometric shoulder strength training resulted in an almost one-scale step decrease in RPE at work and a 5% to 15% improvement of arm motion performance compared with the endurance training. The isometric shoulder strength training more effectively improved left side shoulder abduction strength (p < .026), but no major differences were found for the other strength measurements. The isometric shoulder endurance training was not more successful than the strength training in the endurance test (p .51 to .81). CONCLUSIONS: Physical training programs for neck-shoulder pain may include isometric shoulder muscular strength exercise in addition to isometric shoulder endurance training, rather than endurance training only.

Exercise Therapy↗

Knee extensor strength, activation, and size in very elderly people following strength training.

Muscle strength, activation, and size were studied in 11 very elderly subjects (8 women and 3 men; age range, 85-97 years) who completed 12 weeks of strength training of the knee extensor muscles. Training increased the maximum amount of weight that could be lifted once (134%; P < 0.05) and maximum voluntary isometric strength, measured as both force recorded at the ankle with the knee flexed 90 degrees (17%, ns) and as torque with the knee flexed 60 degrees (37%; P < 0.05). Anatomical lean quadriceps cross-sectional area (LCSA) measured at midthigh using magnetic resonance imaging increased from 27.5 +/- 9.6 cm2 to 30.2 +/- 10.0 cm2 (9.8%; P < 0. 05) after training. Both before and after training, isometric strength was closely related to LCSA, but training resulted in no significant change in muscle force per unit area of quadriceps muscle. Using the twitch interpolation technique, muscle activation during a maximal voluntary isometric contraction was shown to be incomplete in all subjects before training (ranging from 69% to 93%) and was not significantly increased after training. An increase in skeletal muscle mass may have important functional and metabolic benefits for very elderly people.

Aged↗

Strength diagnosis: the use of test data to determine specific strength training.

The aim of this study was to determine if pre-training strength and power tests could provide data that effectively discriminated between subjects whose cycling performance improved considerably from training, from those who did not. Twenty active healthy male subjects performed 10 weeks of plyometric or weight training. Prior to and at the completion of the training, the following tests were performed: (1) a 6-s cycle ride; (2) isokinetic leg extension at 1.05 and 5.24 rads s-1; and (3) a maximum isometric squat. The subjects in the two training groups were separated into those whose cycling performance improved significantly as a result of the training (good) and those who did not (poor). The pre-training muscular function tests of the good versus poor achievers were then compared, individually for each form of training, to determine if they could be used to discriminate between the two subject groups. The pre-training isometric data effectively discriminated between those individuals who improved their cycling performance significantly as a consequence of training and those who did not. While this finding has practical implications for the exercise science field, further research is required before generally useful normative data can be used with confidence to prescribe individual specific training programmes.

Adult↗

Evaluation of protein requirements for trained strength athletes.

Leucine kinetic and nitrogen balance (NBAL) methods were used to determine the dietary protein requirements of strength athletes (SA) compared with sedentary subjects (S). Individual subjects were randomly assigned to one of three protein intakes: low protein (LP) = 0.86 g protein.kg-1.day-1, moderate protein (MP) = 1.40 g protein.kg-1.day-1, or high protein (HP) = 2.40 g protein.kg-1.day-1 for 13 days for each dietary treatment. NBAL was measured and whole body protein synthesis (WBPS) and leucine oxidation were determined from L-[1-13C]leucine turnover. NBAL data were used to determine that the protein intake for zero NBAL for S was 0.69 g.kg-1.day-1 and for SA was 1.41 g.kg-1.day-1. A suggested recommended intake for S was 0.89 g.kg-1.day-1 and for SA was 1.76 g.kg-1.day-1. For SA, the LP diet did not provide adequate protein and resulted in an accommodated state (decreased WBPS vs. MP and HP), and the MP diet resulted in a state of adaptation [increase in WBPS (vs. LP) and no change in leucine oxidation (vs. LP)]. The HP diet did not result in increased WBPS compared with the MP diet, but leucine oxidation did increase significantly, indicating a nutrient overload. For S the LP diet provided adequate protein, and increasing protein intake did not increase WBPS. On the HP diet leucine oxidation increased for S. These results indicated that the MP and HP diets were nutrient overloads for S. There were no effects of varying protein intake on indexes of lean body mass (creatinine excretion, body density) for either group. In summary, protein requirements for athletes performing strength training are greater than for sedentary individuals and are above current Canadian and US recommended daily protein intake requirements for young healthy males.

Adult↗

Trends in strength training--United States, 1998-2004.

Strength training is physical activity intended to increase muscle strength and mass. Adults who engage in strength training are less likely to experience loss of muscle mass, functional decline, and fall-related injuries than adults who do not strength train. Studies on strength-training interventions have indicated that inactive older adults who begin regular strength training achieve substantial strength gains within a few months. Because certain health benefits are linked to strength training, a national health objective for 2010 is to increase to 30% the proportion of adults who perform physical activities that enhance and maintain muscular strength and endurance on > or =2 days per week (objective 22-4). This objective is also recommended by the American College of Sports Medicine. CDC analyzed 1998-2004 data from the National Health Interview Survey (NHIS) to determine the annual prevalence of strength training among U.S. adults by age group and race/ethnicity. This report describes the results of that analysis, which demonstrated that although the national prevalence of strength training for U.S. adults increased slightly during 1998-2004, only 21.9% of men and 17.5% of women (age adjusted) in 2004 reported strength training two or more times per week. This is substantially lower than the national 2010 objective of 30% and underscores the need for additional programs to increase strength training among adults.

Adult↗

Variations in urine excretion of steroid hormones after an acute session and after a 4-week programme of strength training.

Performing strength exercise, whether acutely or in a training programme, leads to alterations at the hypothalamic-pituitary-testicular and hypothalamic-pituitary-adrenal axes. One way to evaluate these changes is by analysis of the excretion of steroid hormones in the urine. The present study determined the variations in the urine profile of glucuroconjugated steroids after a single session of strength exercise and after a 4-week programme of strength training. The subjects were a group (n = 20) of non-sportsman male university students who worked out 3 days a week [Monday (M), Wednesday (W) and Friday (F)], performing the exercises at 70-75% of one repetition maximum strength (1-RM). Four urine samples were collected per subject: (A) before and (B) after a standard session prior to initiating the training programme, and (C) before and (D) after the same standard session at the end of the study, and they were assayed by gas chromatography coupled to mass spectrometry. The concentrations of the different hormones were determined relatively to the urine creatinine level (ng steroid/mg creatinine) to correct for diuresis. After the exercise sessions, both before and after the training programme, there was a fall in the urine excretion of androgens and estrogens, but no statistically significant changes in the excretion of tetrahydrocortisol (THF) and tetrahydrocortisone (THE). The anabolic/catabolic hormones ratio also decreased after the acute session, although only androstenodione + dehydroepiandrosterone (DHEA)/THE + THF ratio had a significant decrease (P < 0.05). After the training programme, there was a significant (P < 0.01) improvement in the strength of the muscle groups studied, and an increased urinary excretion of all the androgens with respect to the initial state of repose, with the difference being significant in the case of epitestosterone (Epit) (P < 0.05). The androsterone (A) + etiocholanolone (E)/THE + THF ratio increased significantly (P < 0.05) concerning the initial state. We therefore conclude that subjects suffer variations of the urine profile with regard to the steroid hormones before and after the acute strength sessions and after the training period. The alteration after the training programme seems to be due to the subjects' hypothalamic-hypophysis-testicular and hypothalamic-pituitary-adrenal axes adaptations, which enable them to increase physical strength.

Adrenal Cortex Hormones↗

[Muscle strength training in old age].

Muscle strength decreases with increasing age. The main causes for this are intrinsic age-dependent mechanisms and hypokinesia. Immobilization and bed rest accelerate the loss of muscle strength. A number of studies show that even very old people can increase their strength, sometimes to a surprising degree. Thus, there is considerable potential for strength training in the rehabilitation of the elderly. Adaptation to strength training, the methods for improving strength and the importance of health problems related to strength training are discussed. If carefully planned and supervised, strength training is feasible even in people with chronic diseases like mild hypertension, coronary heart disease and osteoarthritis; actually, strength training may even be beneficial. Also, strength training becomes increasingly important in rehabilitation after orthopedic surgery.

Aged↗