The effects of respiratory-muscle training on exercise in older women

This research examined the effects of respiratory-muscle (RM) training on RM function and exercise performance in older women. Twenty-six women (60-69 yr of age) were assessed for spirometry, RM strength (maximal inspiratory and expiratory pressure), inspiratory-muscle endurance, and walking performance to a perceived exertion rating of "hard." They were randomly allocated to a threshold RM training group (RMT) or a nonexercising control group (CON) for 8 wk.After training, the 22% (inspiratory) and 30% (expiratory) improvements in RM strength in the RMT group were significantly higher than in the CON group (p < .05). The RMT group also displayed several significant performance improvements, including improved within-group treadmill performance time (12%) and reductions in submaximal heart rate (5%), percentage of maximum voluntary ventilation (16%), and perceived exertion for breathing (8%). RM training appears to improve RM function in older women. Furthermore, these improvements appear to be related to improved submaximal exercise performance.     

Enhancing strength and postocclusive calf blood flow in older people with training with blood-flow restriction

The response of calf-muscle strength, resting blood flow, and postocclusive blood flow (PObf) were investigated after 4 wk of low-load resistance training (LLRT) with and without blood-flow restriction in a matched-leg design. Ten untrained older individuals age 62-73 yr performed unilateral plantar-flexion LLRT at 25% 1-repetition maximum (1RM). One limb was trained with normal blood flow and the other had blood flow restricted using a pressure cuff above the knee. 1RM, isometric maximal voluntary contraction, and isokinetic strength at 0.52 rad/s increased (p < .05) more after LLRT with blood-flow restriction than with normal blood flow. Peak PObf increased (p < .05) after LLRT with blood-flow restriction, compared with no change after LLRT with normal blood flow. These results suggest that 4 wk of LLRT with blood-flow restriction may be beneficial to older individuals to improve strength and blood-flow parameters.     

Effects of strength and power training on neuromuscular variables in older adults

The purpose of this study was to compare the neuromuscular adaptations produced by strength-training (ST) and power-training (PT) regimens in older individuals. Participants were balanced by quadriceps cross-sectional area (CSA) and leg-press 1-repetition maximum and randomly assigned to an ST group (n = 14; 63.6 ± 4.0 yr, 79.7 ± 17.2 kg, and 163.9 ± 9.8 cm), a PT group (n = 16; 64.9 ± 3.9 yr, 63.9 ± 11.9 kg, and 157.4 ± 7.7 cm), or a control group (n = 13; 63.0 ± 4.0 yr, 67.2 ± 10.8 kg, and 159.8 ± 6.8 cm). ST and PT were equally effective in increasing (a) maximum dynamic and isometric strength (p < .05), (b) increasing quadriceps muscle CSA (p < .05), and (c) decreasing electrical mechanical delay of the vastus lateralis muscle (p < .05). There were no significant changes in neuromuscular activation after training. The novel finding of the current study is that PT seems to be an attractive alternative to regular ST to maintain and improve muscle mass.     

Leg-extension strength and chair-rise performance in elderly women with Parkinson's disease

The lower extremity performance in elderly female patients with mild to moderate Parkinson's disease (PD; n = 12) and controls (n = 16) was compared. Isometric dynamometry and force-plate measurements were used. PD patients had lower (p < .05) bilateral (BL) maximal isometric leg-extension force (MF), BL isometric MF relative to body mass, and maximal rate of isometric force development than control participants. BL strength deficit was greater (p < .05) in PD patients than in controls. A significantly longer chair-rise time and lower maximal rate of vertical-ground-reaction-force development while rising from a chair was found in PD patients than in controls. These findings suggest that elderly women with PD have lowered voluntary isometric force-generation capacity of the leg-extensor muscles. Reduced BL leg-extension strength might contribute to the difficulty of individuals with PD to rise from a chair.     

Effects of exercise training with weighted vests on bone turnover and isokinetic strength in postmenopausal women

The effects of 12 wk of exercise training using weighted vests on bone turnover and isokinetic strength were evaluated in postmenopausal women randomly assigned as exercisers (EX; n = 9) or controls (CON; n = 7). Training included 3 multimodal exercise sessions per wk wearing weighted vests. The vest load was progressively increased each wk to a maximum of 15% of body weight. Bone turnover was determined from resting levels of serum osteocalcin and NTx. Knee and ankle strength were measured at 60 degrees/s and 180 degrees/s using an isokinetic dynamometer. After 12 wk, NTx decreased by 14.5% (P 相似文献   

Relationships between muscle strength and multi-channel surface EMG parameters in eighty-eight elderly

Background

Since age-related muscle strength loss cannot be explained solely by muscle atrophy, other determinants would also contribute to muscle strength in elderly. The present study aimed to clarify contribution of neuromuscular activation pattern to muscle strength in elderly group. From 88 elderlies (age: 61~?83 years), multi-channel surface electromyography (EMG) of the vastus lateralis muscle was recorded with two-dimensional 64 electrodes during isometric submaximal ramp-up knee extension to assess neuromuscular activation pattern. Correlation analysis and stepwise regression analysis were performed between muscle strength and the parameters for signal amplitude and spatial distribution pattern, i.e., root mean square (RMS), correlation coefficient, and modified entropy of multi-channel surface EMG.

Results

There was a significant correlation between muscle strength and RMS (r =?0.361, p =?0.001) in the elderly. Muscle thickness (r =?0.519, p <?0.001), RMS (r =?0.288, p?=?0.001), and normalized RMS (r =?0.177, p =?0.047) were selected as major determinants of muscle strength in stepwise regression analysis (r?=?0.664 in the selected model).

Conclusion

These results suggest that inter-individual difference in muscle strength in elderly can be partly explained by surface EMG amplitude. We concluded that neuromuscular activation pattern is also major determinants of muscle strength on elderly in addition to indicator of muscle volume.

     

Effects of vibration exercise on muscle performance and mobility in an older population

This study was designed to investigate the effects of vibration on muscle performance and mobility in a healthy, untrained, older population. Forty-three participants (23 men, 20 women, 66-85 y old) performed tests of sit-to-stand (STS), 5- and 10-m fast walk, timed up-and-go test, stair mobility, and strength. Participants were randomly assigned to a vibration group, an exercise-withoutvibration group, or a control group. Training consisted of 3 sessions/wk for 2 mo. After training, the vibration and exercise groups showed improved STS (12.4%, 10.2%), 5-m fast walk (3.0%, 3.7%), and knee-extension strength (8.1%, 7.2%) compared with the control (p < 0.05). Even though vibration training improved lower limb strength, it did not appear to have a facilitatory effect on functional-performance tasks compared with the exercise-without-vibration group. Comparable mobility and performance changes between the experimental groups suggest that improvements are linked with greater knee-extension strength and largely attributed to the unloaded squats performed by both exercise groups.     

Force steadiness in the lower extremities as an independent predictor of functional performance in older women

The relationship between isometric force control and functional performance is unknown. Submaximal steadiness and accuracy were measured during a constant force-matching task at 50% of maximal isometric voluntary contraction (MVC) of the knee extensors in 19 older women (70-89 years). Other variables included MVC, rate of torque development, and EMG activity. Functional performance was assessed during maximal performance of walking endurance, chair rising, and stair climbing. Isometric steadiness (but not accuracy) was found to independently predict chair-rise time and stair-climbing power and explained more variance in these tasks than any other variable. Walking endurance was related to muscle strength but not steadiness. These results suggest that steadiness is an independent predictor of brief, stressful functional-performance tasks in older women with mild functional impairment. Thus, improving steadiness might help reduce functional limitations or disability in older adults.     

Meditation lowers stress and supports forgiveness among college students: a randomized controlled trial

OBJECTIVE AND PARTICIPANTS: The authors evaluated the effects on stress, rumination, forgiveness, and hope of two 8-week, 90-min/wk training programs for college undergraduates in meditation-based stress-management tools. METHODS: After a pretest, the authors randomly allocated college undergraduates to training in mindfulness-based stress reduction (MBSR; n = 15), Easwaran's Eight-Point Program (EPP; n = 14), or wait-list control (n = 15). The authors gathered pretest, posttest, and 8-week follow-up data on self-report outcome measures. RESULTS: The authors observed no post-treatment differences between MBSR and EPP or between posttest and 8-week follow-up (p > .10). Compared with controls, treated participants (n = 29) demonstrated significant benefits for stress (p < .05, Cohen's d = -.45) and forgiveness (p < .05, d = .34) and marginal benefits for rumination (p < .10, d = -.34). CONCLUSIONS: Evidence suggests that meditation-based stress-management practices reduce stress and enhance forgiveness among college undergraduates. Such programs merit further study as potential health-promotion tools for college populations.     

The effect of functional circuit training on physical frailty in frail older adults: a randomized controlled trial

The purpose of this study was to evaluate whether a 12-wk functional circuit-training program (FCT) could alter markers of physical frailty in a group of frail community-dwelling adults. Fifty-one individuals (31 women, 20 men), mean age (± SD) 84 (± 2.9) yr, met frailty criteria and were randomly assigned into groups (FCT = 26, control group [CG] = 25). FCT underwent a 12-wk exercise program. CG met once a week for health education meetings. Measures of physical frailty, function, strength, balance, and gait speed were assessed at Weeks 0, 12, and 36. Physical-frailty measures in FCT showed significant (p < .05) improvements relative to those in CG (Barthel Index at Weeks 0 and 36: 73.41 (± 2.35) and 77.0 (± 2.38) for the FCT and 70.79 (± 2.53) and 66.73 (± 2.73) for the CG. These data indicate that an FCT program is effective in improving measures of function and reducing physical frailty among frail older adults.     

Effect of ceasing creatine supplementation while maintaining resistance training in older men

The authors previously found that creatine (Cr) combined with 12 weeks of resistance training enhanced muscle strength and endurance and lean tissue mass (LTM) in older men. Their purpose in this study was to assess these variables with cessation of Cr combined with 12 weeks of reduced training (33% lower volume) in a subgroup of these men (n = 8, 73 years old) compared with 5 men (69 years old) who did not receive Cr. Strength (1-repetition maximum [1-RM]), endurance (maximum number of repetitions over 3 sets at 70-80% 1-RM), and LTM (dual-energy X-ray absorptiometry) were assessed before and after 12 weeks of Cr cessation combined with reduced-volume training. No changes in strength or LTM occurred. Muscle endurance was significantly reduced (7-21%; p <.05), with the rate of change similar between groups. Withdrawal from Cr had no effect on the rate of strength, endurance, and loss of lean tissue mass with 12 weeks of reduced-volume training.     

Strength-training behavior and perceived environment among Japanese older adults

The authors examined the relationship between strength-training behavior and perceived environment in older Japanese adults. An Internet-based survey was conducted of 293 adults age 68.2 ± 2.8 yr. The dependent variable was regular strength-training behavior. The IPAQ environment module, access to facilities for strength training, and home equipment for strength training were environmental factors. Logistic-regression analysis was employed. After demographic variables (gender, age, educational background, household income, body-mass index, self-rated health status, smoking habit, and residential area) were adjusted for, home equipment for strength training (OR = 2.14, 95% CI = 1.50-3.06), access to facilities for strength training (OR = 2.53, 95% CI = 1.32-4.85), and observing active people (OR = 2.20, 95% CI = 1.06-4.58) were positively correlated with regular strength-training behavior. In conclusion, environmental factors associated with strength-training behavior were access to facilities for strength training, having home equipment for strength training, and observing active people.     

The effect of 6 months training on leg power, balance, and functional mobility of independently living adults over 70 years old

Where strength training has been used in conjunction with functional-task training in older people, not only have there been improvements in leg strength but also improved function has been measured (e.g., Skelton & McLaughlin, 1996). Many studies use participants from care homes rather than community dwellers. We investigated changes in leg power, balance, and functional mobility in community-dwelling sedentary men and women over 70 years of age (n = 6 for training group [TR]; n = 10 for control group [CN]). Progressive training took place over 24 weeks using seated and nonseated exercise. For TR, leg power increased 40%, from 108 +/- 40 to 141 +/- 53 W (p < .01); dynamic balance increased 48%, from 22.3 +/- 7.9 to 33.1 +/- 6.1 cm (p < .01; functional reach); and functional mobility increased 12%, from 7.46 +/- 1.32 to 6.54 +/- 1.41 s (p < .05; timed walk). CN showed no significant change. In conclusion, a community-based exercise program led to large improvements in leg-extensor power, dynamic balance, and functional mobility.     

Physical and psychological outcomes of a supported physical activity program for older carers

This study evaluated health benefits of a supported physical activity program for 116 older carers (mean age 64.4 [SD = 7.9], 85% women). Participants undertook a 6-month center-based physical activity program (strength training, yoga, or Tai Chi). Eighty-eight participants (76%) completed the program. Multivariate repeated-measures ANOVA identified overall significant improvement postintervention (p = .004). Univariate analyses revealed significant improvements for balance, strength, gait endurance, depression, and SF-36 (physical component; p < .05). There was no change in the Zarit Carer Burden Scale (p > .05). Change in performance scores did not differ significantly between those with higher and lower attendance at classes, although there was significantly greater improvement in gait endurance and balance (p < .05) in those attending classes run twice weekly than in those attending once-weekly classes. In conclusion, a carer physical activity program, providing additional carer support to facilitate participation, can achieve high levels of involvement by carers and significant health benefits.     

Reliability of normalisation methods for EMG analysis of neck muscles

Acceptable reliability of normalisation contractions in electromyography (EMG) is paramount for testing conducted over a number of days or if normal laboratory strength testing equipment is unavailable. This study examined the reliability of maximal voluntary isometric contractions (MVIC) and sub-maximal (60%) isometric contractions for use in neck muscle EMG studies. Surface EMG was recorded bilaterally from eight sites around the neck at C4/5 level from five healthy male subjects. Subjects performed MVIC and sub-maximal normalisation contractions using an isokinetic dynamometer (ID) and a portable cable dynamometer with attached strain gauge (PCD) in addition to a MVIC against a manual resistance (MR). Subjects were tested in flexion, extension, left and right lateral bending and were retested by the same tester within a two-week period. Intra class correlation co-efficients (ICC) were calculated for each testing method and contraction direction and a mean ICC was calculated across all contraction directions. All normalisation methods produced excellent within-day reliability (mean ICC >0.80) but only the MVICs using the ID and PCD had acceptable reliability when assessed between-days. This study confirmed the validity of using MVICs elicited using the ID and PCD as reliable reference contractions for the normalisation of neck EMG.     

Endurance exercise and leg strength in older women

Quadriceps strength and mass peak in the third decade of life, plateau, and then decline from the fifth decade on. To examine the influence of chronic endurance training and age on lean mass and leg strength, women runners (n = 62, age 43-69 years) and sedentary participants (n = 33, age 43-66 years) were divided into 40-, 50-, and 60-year age groups. Absolute isokinetic concentric torque did not differ between runners and sedentary women (97.9 +/- 19.5 and 104.6 +/- 22.7 N . m, respectively, p = .18) but was different between age groups independent of exercise status (107.6 +/- 18.4, 97.1 +/- 19.9, and 90.1 +/- 21.4 N . m, for 40s, 50s, and 60s, respectively, p < .05). Lean body mass also differed by age group (p < .05) but did not change differently among runners and sedentary women. These findings suggest that chronic endurance training might not influence the loss of muscle mass and muscle strength that occur with aging.     

Improvements in functional capacity from Nordic walking: a randomized-controlled trial among elderly people

This study examined the effects of an instructed structured Nordic walking (NW) exercise program on the functional capacity of older sedentary people. Volunteers were randomly assigned to an NW group (68.2 ± 3.8 yr old) or control group (69.9 ± 3.0 yr old). Before and at the end of the 9-wk intervention, functional tests and 2-dimensional ground-reaction-force (GRF) patterns of normal (1.40 m/s) and fast (1.94 m/s) walking speeds were measured. The intervention included a 60-min supervised NW session on an inside track twice a week for 9 wk. The mean changes in functional tests differed between groups significantly. Gait analyses showed no significant differences between the groups on any GRF parameters for walking speed either before or after the intervention. The study showed that NW has favorable effects on functional capacity in older people and is a suitable form of exercise for them.     

The motor-learning process of older adults in eccentric bicycle ergometer training

This study describes the motor-learning process of older individuals during the course of a training intervention on a motor-driven eccentric bicycle ergometer. Seventeen women and 16 men (64 ± 6 yr) took part in a 10-wk training program. Uniformity of force production and consistency of timing were used to describe their motor performance. The results suggested that participants improved the coefficient of variation of peak force during the intervention (measured at the 2nd, 4th, 6th, 8th, 10th, 12th, and the 18th training sessions). They reached a fairly constant level of motor performance around the 12th training session (5 wk). Age and sex affected improvements in the early phases of the learning process to an extent, but the differences diminished by the end of the intervention. These results suggest that the force control of continuous eccentric muscle contractions improves as a result of training in older adults.     

Age-related changes in maximal power and maximal heart rate recorded during a ramped test in 114 cyclists age 15-73 years

This study assessed age-related changes in power and heart rate in 114 competitive male cyclists age 15-73 years. Participants completed a maximal Kingcycle ergometer test with maximal ramped minute power (RMPmax, W) recorded as the highest average power during any 60 s and maximal heart rate (HRmax, beats/min) as the highest value during the test. From age 15 to 29 (n = 38) RMPmax increased by 7.2 W/year (r = .53, SE 49 W, p < .05). From age 30 to 73 (n = 78) RMPmax declined by 2.4 W/year (r = - .49, SE 49 W, p < .05). Heart rate decreased across the full age range by 0.66 beats . min( -1 ) . year( -1 ) (r = -.75, SE 9 beats/min, p < .05). Age accounted for only 25% of the variance in RMPmax but 56% in HRmax. RMPmax was shown to peak at age 30, then decline with age, whereas HRmax declined across the full age range.     

No sustained effect of aerobic or resistance training on insulin sensitivity in nonobese, healthy older women

It is unclear whether long-term aerobic (AT) or resistance (RT) training can improve insulin sensitivity (IS) beyond the residual effect of the last training bout in older women (54-78 years). Therefore, a group of nonobese, healthy older women underwent 6 months of AT (n = 8) or RT (n = 10), and the authors measured IS 4 days after the last training bouts using the hyperinsulinemic-euglycemic clamp technique. Women trained 3 days/week. AT consisted of 25- to 60-min sessions of walking/jogging at 60-95% of maximal heart rate. RT consisted of three sets of nine exercises repeated 10 times at 80% of 1 repetition maximum. AT decreased fat mass, whereas both AT and RT increased fat-free mass. Neither training program, however, improved absolute or relative rates of glucose disposal. The authors therefore concluded that nonobese, healthy older women should perform AT or RT on a daily basis in order to improve IS and maintain the improvement.