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.     

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.     

Reliability and effects of muscular pretension on isometric strength of older adults

There were two objectives to this study: (a) to determine the reliability of measuring isometric maximum torque (MT) and maximum rate of torque development (MRTD) of the knee extensor and flexor muscles and (b) to assess the effects of different muscular pretensions on MT and MRTD of older adults. Maximum strength of 35 untrained healthy older adults (aged 66.9?±?6.6 years; height 1.72?±?0.07 m; weight 75.2?±?9.6 kg) was measured. Strength measurement was performed with the Dr. Wolff ISO Check using a piezo-electric force transducer. MT intra-day coefficient of variation (CV) was between 3.30 and 12.40 % for both measurement sessions. Intraclass correlation coefficients (ICC) ranging from 0.71 to 0.99 showed good relative reliability. MT test–retest reliability (between sessions 1 and 2) of knee extension reached a CV between 7.10 and 9.30 % and high ICC values. The measurement of the knee flexion achieved an acceptable CV (9.40 %) at 40 % muscular pretension. MRTD was negatively influenced by muscular pretension (p <0.05). In conclusion, MT could be measured reliably over different trials using isometric strength measurement. The test–retest reliability was acceptable at knee extension with 10 to 40 % muscular pretension and with 40 % muscular pretension at knee flexion. A higher muscular pretension has no impact on MT but decreases MRTD in older adults.     

Changes in health-related quality of life in elderly men after 12 weeks of strength training

Background

Muscular strength is associated with functional ability in elderly, and older adults are recommended to perform muscle-strengthening exercise. Understanding how improved muscle strength and -mass influence general and specific domains of quality of life is important when planning health promotion efforts targeting older adults. The aims of the present study were to describe changes in health-related quality of life (HRQOL) in older men participating in 12 weeks of systematic strength training, and to investigate whether improvements in muscle strength and muscle mass are associated with enhancements in HRQOL.

Methods

We recruited 49 men aged 60–81 years to participate in an intervention study with pre-post assessment. The participants completed a 12-week strength training program consisting of three sessions per week. Tests and measurements aimed at assessing change in HRQOL, and changes in physical performance (maximal strength) and physiological characteristics. HRQOL was measured using the 12-item short-form survey (SF-12). Muscle mass was assessed based on changes in lean mass (leg, trunk, arm, and total), and strength was measured as one-repetition maximum in leg extension, leg press, and biceps curl.

Results

Two of the eight HRQOL SF-12 scores, role physical and general health, and the physical component summary scores, increased significantly during the intervention period. Small significant positive correlations were identified between improvements in muscle strength, and better physical and social function. Moreover, a significant increase in total muscle mass was seen during the intervention period.

Conclusions

The positive, findings from this study would suggest that systematic strength training seems to be a beneficial intervention to improve HRQOL, muscle strength and muscle mass in older men.

     

Functional benefit of power training for older adults

Aging leads to significant losses in muscle mass, strength, and the ability to independently perform activities of daily living (ADL). Typically, standard resistance training (RT) has been used to reduce these losses in function by maintaining or even increasing muscle strength in older adults. Increasing strength does not necessarily, however, result in an increase in the ability to perform ADL. There is now research suggesting that muscle power is more closely associated with the performance of ADL than muscle strength is, so training for muscle power might lead to more beneficial results in functional performance. This review of studies investigating the effect of training on ADL performance in older adults indicated that standard RT is effective in increasing strength in older adults, but power training that contains high-velocity contractions might be a more optimal means of training older adults when the emphasis is on increasing the performance of ADL.     

Effects of an 8-week multimodal exercise program on strength, flexibility, and golf performance in 55- to 79-year-old men

Substantial research has indicated the beneficial effect of physical activity on physical fitness and activities of daily living in older adults, but none have investigated the effects on performance of recreational activities. This investigation studied the effect of an exercise program on fitness and golf-clubhead speed in older men. Thirty-one golfers (mean age 65.1 +/- 6.2 years) were randomly assigned to a treatment (n = 19) or control (n = 12) group. The treatment group completed an 8-week strength and flexibility program. Assessments included 10-RM muscle strength; selected range-of-motion (ROM) measurements; and golf-clubhead speed (CHS). ANCOVA revealed significant differences between groups (p <.005) for all strength measurements and several ROM measurements. CHS was significantly different (p <.05) between groups after the intervention. Mean CHS improved from 85.0 to 87.1 miles/hr (136.8 to 140.2 km/hr). These results indicate that a strength and flexibility program can improve golf performance in older adults.     

Comparison of heart-rate and blood-pressure increases during isokinetic eccentric versus isometric exercise in older adults

The authors compared heart-rate and blood-pressure responses to typical isometric (ISO) and isokinetic (90 degrees /s) eccentric (ECC) resistance-training protocols in older adults. Twenty healthy older adults (74 +/- 5 years old) performed randomly ordered ISO and isokinetic ECC exercise (3 sets of 10 repetitions) at a target intensity of 100 % of their peak ISO torque value. Heart rate and systolic (SBP) and diastolic (DBP) blood pressures were recorded continuously, and mean arterial pressure (MAP) and rate-pressure product (RPP) were calculated. ECC peak torque (139 +/- 33 N. m) was significantly greater than ISO peak torque (115 +/- 26 N. m; p <.001). All variables increased significantly (p <.001) during both ISO and ECC exercise. Changes in SBP, DBP, MAP, and RPP were significantly greater during ISO exercise than during ECC exercise (p <.001). Clinically, an isokinetic ECC exercise program enables older adults to work at the same torque output with less cardiovascular stress than ISO exercise.     

The influence of familiarization sessions on the stability of ramp and ballistic isometric torque in older adults

Ramp isometric contractions determine peak torque (PT) and neuromuscular activation (NA), and ballistic contractions can be used to evaluate rate of torque development (RTD) and electrical mechanical delay (EMD). The purposes of this study were to assess the number of sessions required to stabilize ramp and ballistic PT and to compare PT and NA between contractions in older adults. Thirty-five older men and women (age 63.7 ± 3.7 yr, body mass 64.3 ± 10.7 kg, height 159.2 ± 6.6 cm) performed 4 sessions of unilateral ramp and ballistic isometric knee extension, 48 hr apart. PT significantly increased (main time effect p < .05) from the first to the third session, with no further improvements thereafter. There was a trend toward higher PT in ballistic than in ramp contractions. No difference between contraction types on EMG values was observed. Therefore, the authors suggest that 3 familiarization sessions be performed to correctly assess PT. In addition, PT, NA, RTD, and EMD can be assessed with ballistic contraction in older adults.     

Relation between hand grip strength,respiratory muscle strength and spirometric measures in male nursing home residents

Abstract

Adverse-outcomes related to sarcopenia are mostly mentioned as physical disability. As the other skeletal muscles, respiratory muscles may also be affected by sarcopenia. Respiratory muscle strength is known to affect pulmonary functions. Therefore, we aimed to investigate the relations between extremity muscle strength, respiratory muscle strengths and spirometric measures in a group of male nursing home residents. Among a total of 104 male residents, residents with obstructive measures were excluded and final study population was composed of 62 residents. Mean age was 70.5?±?6.7 years, body mass index: 27.7?±?5.3?kg/m² and dominant hand grip strength: 29.7?±?6.5?kg. Hand grip strength was positively correlated with maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) (r?=?0.35, p?<?0.01 and r?=?0.26, p?<?0.05, respectively). In regression analysis, the only factor related to MIP was hand grip strength; among spirometric measures only parameter significantly related to grip strength was peak cough flow (PCF). The association of PCF with grip strength disappeared when MIP alone or “MIP and MEP” were included in the regression analysis. In the latter case, PCF was significantly associated only with MIP. We found peripheric muscle strength be associated with MIP and PCF but not with MEP or any other spirometric parameters. The relation between peripheral muscle strength and PCF was mediated by MIP. Our findings suggest that sarcopenia may affect inspiratory muscle strength earlier or more than the expiratory muscle strength. Sarcopenia may cause decrease in PCF in the elderly, which may stand for some common adverse respiratory complications.     

Uncomplicated diabetes does not accelerate age-related sarcopenia

Abstract

Background: Diabetes is reported to accelerate sarcopenia (age-related loss of muscle mass and function). We aimed to assess muscle mass and strength in elderly diabetics, elderly non-diabetics, younger diabetics and healthy subjects, and to define correlates of muscle mass and strength in these subjects.

Methods: Sixteen elderly diabetics, 16 younger diabetics, 16 elderly non-diabetics and 18 younger non-diabetics were included. Elderly and diabetic subjects were first evaluated with exercise testing. Isokinetic leg extension and flexion tests were performed using a Cybex 350 dynamometer. Muscle mass was calculated using bioelectric impedance analysis.

Results: Muscle mass was similar between all groups; however, muscle strength was significantly lower in diabetic and non-diabetic elderly subjects compared with younger diabetic subjects and non-diabetics. Muscle strength was positively correlated with albumin, metabolic equivalent and hemoglobin, and inversely correlated with age, HbA1c, functional capacity and CRP. Independent correlates of muscle strength were age and hemoglobin. There was no clinically significant correlate of muscle mass. Presence or duration of diabetes was not associated with muscle mass or strength.

Conclusions: Uncomplicated diabetes does not seem to accelerate aging-related muscle mass or strength loss. Exercise test parameters may be useful markers in the screening of sarcopenia.     

Muscle-power quality: does sex or race affect movement velocity in older adults?

To determine sex and race differences in muscle power per unit of muscle contraction, knee-extensor muscle power normalized for knee-extensor muscle volume was measured in 79 middle-aged and older adults (30 men and 49 women, age range 50-85 years). Results revealed that women displayed a 38% faster peak movement velocity than men and African Americans had a 14% lower peak movement velocity than Whites of a similar age when expressed per unit of involved muscle (p < .001). As expected, men exhibited greater knee-extensor strength and peak power per unit of muscle than women, but women had a faster knee- extension movement velocity per unit of muscle than men at the same relative strength level. Moreover, African Americans had greater knee-extensor muscle volume than Whites but exhibited lower knee-extensor strength and lower movement velocity per unit of muscle when tested at the same relative strength levels.     

Alterations in IGF-I affect elderly: role of physical activity

The growth hormone–insulin-like growth factor I (IGF-I) axis is an important physiological regulator muscle for development. Although there is evidence that aging muscle retains the ability to synthesize IGF-I, there is also evidence that aging may be associated with attenuation of the ability of exercise to induce an isoform of IGF-I that promotes satellite cell proliferation. However, it is clear that overexpression of IGF-I in the muscle can protect against age-related sarcopenia. Strength training appears to be the intervention of choice for the prevention and treatment of sarcopenia. IGF-I has been implicated in the loss of the muscle with age, and IGF-I expression levels change as a consequence of strength training in older adults. However, it seems that advancing age, rather than declining serum levels of IGF-I, appears to be a major determinant of life-time changes in body composition in women and men. We concluded that resistive exercise is a significant determinant of muscle mass and function. Elevated levels of IGF-I have been found in physically active compared to sedentary individuals. Recent work suggests that IGF-I as a mediator plays an important role in muscle hypertrophy and angiogenesis, both of which characterize the anabolic adaptation of muscles to exercise.     

Stair-ascent performance in elderly women: effect of explosive strength training

Explosive-type strength training may alter kinetics and neuromuscular activity during stair ascent in elderly women. This may improve functional ability. Nineteen women (69.7 ± 3.4 yr) were randomly allocated to strength training (TG; twice per wk, 12 wk) or a control group (CG). Stair ascent was assessed at self-chosen (AFV), standardized (ASV), and maximal velocity (AMV) pre- and posttraining. Ground-reaction force (GRF) and EMG quantified kinetics and neuromuscular activity. After training, TG increased AMV and AFV velocity by 8% (p = .02) and 17% (p= .007), respectively (TG vs. CG; p< .05). This was accompanied by elevated rectus femoris EMG (from 21% to 48%, p< .047). At AFV, TG increased GRF first peak force 4% (p= .047), and CG increased second peak force 5% (p = .036). Muscle coactivation remained unaltered in both groups. Explosive-type strength training led to enhanced stair-climbing performance at maximal and self-chosen speed, reflecting an improved functional ability.     

Anaerobic performance in masters athletes

With increasing age, it appears that masters athletes competing in anaerobic events (10–100 s) decline linearly in performance until 70 years of age, after which the rate of decline appears to accelerate. This decline in performance appears strongly related to a decreased anaerobic work capacity, which has been observed in both sedentary and well-trained older individuals. Previously, a number of factors have been suggested to influence anaerobic work capacity including gender, muscle mass, muscle fiber type, muscle fiber size, muscle architecture and strength, substrate availability, efficiency of metabolic pathways, accumulation of reaction products, aerobic energy contribution, heredity, and physical training. The effects of sedentary aging on these factors have been widely discussed within literature. Less data are available on the changes in these factors in masters athletes who have continued to train at high intensities with the aim of participating in competition. The available research has reported that these masters athletes still demonstrate age-related changes in these factors. Specifically, it appears that morphological (decreased muscle mass, type II muscle fiber atrophy), muscle contractile property (decreased rate of force development), and biochemical changes (changes in enzyme activity, decreased lactate production) may explain the decreased anaerobic performance in masters athletes. However, the reduction in anaerobic work capacity and subsequent performance may largely be the result of physiological changes that are an inevitable result of the aging process, although their effects may be minimized by continuing specific high-intensity resistance or sprint training.     

The differences of sarcopenia-related phenotypes: effects of gender and population

Sarcopenia is a serious condition especially in the elderly population mainly characterized by the loss of skeletal muscle mass and strength with aging. Extremity skeletal muscle mass index (EMMI) (sum of skeletal muscle mass in arms and legs/height²) is gaining popularity in sarcopenia definition (less than two standard deviations below the mean of a young adult reference group), but little is known about the gender- and population-specific differences of EMMI. This study aimed at investigating the differences of EMMI, arm muscle mass index (AMMI), and leg muscle mass index (LMMI) between gender groups and populations (Chinese vs. Caucasians). The participants included 1,809 Chinese and 362 Caucasians with normal weight aged from 19 to 45 years old. Extremity muscle mass, arm muscle mass, and leg muscle mass were measured by using dual energy x-ray absorptiometry. Independent sample t tests were used to analyze the differences in muscle mass indexes between the studied groups. All the study parameters including EMMIs, AMMIs, and LMMIs were significantly higher (P ≤ 0.0003) in the Caucasian group than in the Chinese group and also higher in the male group than in the female group, and these significant differences (P ≤ 0.0005) remained after adjusting for age by simple regressions. The detected differences of muscle mass indexes between different gender and ethnic groups may provide important implications in their different risk of future sarcopenia.     

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.     

Misconceptions about strength exercise among older adults

The purposes of this study were to determine current opinions of strength exercise among older adults and whether knowledge of recommended protocols differs between strength-exercise participants and nonparticipants. One hundred twenty-nine older adults (77.5 +/- 8.6 years) responded to questions about their opinions, experiences, and knowledge of strength-exercise recommendations. Some misconceptions were identified in the sample, with 48.4% of participants responding "no" to "strength training increases muscle mass," 45% responding "no" to "increasing weight is more important than number of repetitions for building strength," and 37% responding that walking is more effective than lifting weights at building muscle strength. The number of correct responses was related to the number of years in school (semipartial r(2)= .046). More education is needed about the benefits and recommendations to ensure proper use of current strength-exercise protocols among older adults.     

Suggestions for assessment of muscle mass in primary care setting

Sarcopenia is one of the prevalent geriatric syndromes that adversely affects the functionality in the older adults. The diagnosis of sarcopenia requires documentation of decreased muscle mass and decreased muscle strength or physical function. The implication of user-friendly and inexpensive methods that could be used to assess sarcopenia in real-life settings is suggested in a recent debate paper. For muscle mass assessment, bioelectric impedance analysis (BIA), and dual-energy X-ray absorptiometry (DXA) were described as having the same ease for muscle mass assessment in terms of applicability. However, BIA is easier to perform, has greater availability, inexpensive, and does not require specialist trained staff. The authors proposed the use of DXA as primary tool to assess muscle mass in the primary care setting. However, BIA is recommended as a first-line method both in research and clinical practice by EWGSOP. Regarding its much easier applicability, we conclude that BIA is a more practical method for muscle mass assessment in the primary care setting than the DXA. Thus, we suggest that BIA could be the method of choice for muscle mass assessment in the primary care setting.     

Optimal health and function among the elderly: lessening severity of ADL disability

Despite mounting evidence implicating sedentary behavior as a significant risk factor among the elderly, there is a limited amount of information on the type and amount of activity needed to promote optimal health and function in older people. Overall muscle strength and mass decline 30–50% between the ages of 30 and 80. The loss of muscle mass accounts for most of the observed loss of strength. The loss of muscle tissue is due to a decrease in the number of muscle fibers and to atrophy of the type II muscle fibers. The declining strength reduces the capacity to carry out basic activities of daily life and puts people at risk for falls and dependence on others. The objective of the present review is to examine the role of exercise training as a primary tool for increasing cardiopulmonary and muscular fitness in order to lessen the severity of disability in activities of daily living and to attain optimal health and functioning among the elderly.     

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.