The influence of isokinetic peak torque and muscular power on the functional performance of active and inactive community-dwelling elderly: a cross-sectional study

Are dose-response relationships of resistance training reliable to improve functional performance in frail and pre-frail older adults? A systematic review with meta-analysis and meta-regression of randomized controlled trials

This systematic review with meta-analyses investigates the impact of resistance training (RT), using meta-regressions, on functional performance in frail and pre-frail adults aged ≥ 65 years to determine the key variables of RT. Ten randomized controlled trials involving 1303 participants were analyzed. Five studies assessed habitual walking speed (HWS), three studies evaluated performance in the timed-up-and-go test (TUG), three studies evaluated performance in the Short Physical Performance Battery (SPPB), and three studies assessed performance in the sit-to-stand test (STS). RT alone improved STS time and SPPB scores in frail and pre-frail older adults. RT improved STS performance (Effect Size (ES):- 0.536; 95% CI - 0.874 to - 0.199; p = .002) and led to a 2.261-point increase in SPPB performance (ES:1.682; 95% CI 0.579-2.786; p = .003). At least two weekly training sessions are required to increase SPPB scores, and three sessions seem to optimize the improvements. Higher training volume per exercise and volume per session reduce the gains in SPPB performance. We did not observe any association between different doses of RT and STS time improvements. RT alone positively influenced TUG performance only in community-dwelling older frail and pre-frail adults but not in institutionalized older individuals. RT alone did not improve the HWS compared to the non-active control group.

Short-term beetroot juice supplementation improves muscle speed and power but does not reduce blood pressure or oxidative stress in 65-79 y old men and women

We have previously demonstrated that acute ingestion of inorganic nitrate (NO3-)-rich beetroot juice (BRJ), a source of nitric oxide (NO) via the NO3- → nitrite (NO2-) → NO pathway, can improve muscle speed and power in older individuals. It is not known, however, whether this effect is maintained or perhaps even enhanced with repeated ingestion, or if tolerance develops as with organic nitrates, e.g., nitroglycerin. Using a double-blind, placebo-controlled, crossover design, we therefore studied 16 community-dwelling older (age 71 ± 5 y) individuals after both acute and short-term (i.e., daily for 2 wk) BRJ supplementation. Blood samples were drawn and blood pressure was measured periodically during each ∼3 h experiment, with muscle function determined using isokinetic dynamometry. Acute ingestion of BRJ containing 18.2 ± 6.2 mmol of NO3- increased plasma NO3- and NO2- concentrations 23 ± 11 and 2.7 ± 2.1-fold over placebo, respectively. This was accompanied by 5 ± 11% and 7 ± 13% increases in maximal knee extensor speed (Vmax) and power (Pmax), respectively. After daily supplementation for 2 wk, BRJ ingestion elevated NO3- and NO2- levels 24 ± 12 and 3.3 ± 4.0-fold, respectively, whereas Vmax and Pmax were 7 ± 9% and 9 ± 11% higher than baseline. No changes were observed in blood pressure or in plasma markers of oxidative stress with either acute or short-term NO3- supplementation. We conclude that both acute and short-term dietary NO3- supplementation result in similar improvements in muscle function in older individuals. The magnitudes of these improvements are sufficient to offset the decline resulting from a decade or more of aging and are therefore likely to be clinically significant.

Exploring the factors associated with decreased dynamic balance ability in older patients with heart failure

BACKGROUND

Older patients with heart failure (HF) have a higher prevalence of frailty and poorer dynamic balance ability than other community-dwelling older adults. However, the association of frailty and other clinical characteristics with dynamic balance ability in these patients remains unclear.

OBJECTIVES

We aimed to determine the clinical characteristics associated with decreased dynamic balance ability in older patients with HF.

METHODS

This observational study included patients aged ≥65 years who could walk independently and were admitted to our university hospitals to undergo a cardiac rehabilitation. The timed up and go test (TUG) was used to evaluate dynamic balance ability. Pearson's and Spearman's correlation analyses were performed to determine the relationships between TUG scores and clinical characteristics. A multiple regression model based on the forced entry method was used to determine independent predictors of TUG scores.

RESULTS

Of the 183 participants in this study (94 women; mean age, 82.5 ± 8.1 years), 116 (61.7%) had frailty. Pearson's and Spearman's correlation analyses revealed that age, frailty, sex, knee extensor muscle strength, maximum calf circumference, and Mini-Mental State Examination-Japanese version (MMSE-J) score were significantly correlated with TUG score (p < 0.001). Further, multiple regression analysis showed that age (p < 0.001), frailty (p = 0.041), knee extensor muscle strength (p = 0.002), and MMSE-J score (p = 0.048) were independent predictors of TUG scores.

CONCLUSION

Multiple factors, including age, frailty, knee extensor muscle weakness, and cognitive function impairment are independently associated with decreased dynamic balance ability in older patients with HF.

Reproducibility of isokinetic measures of the knee and ankle muscle strength in community-dwelling older adults without and with Alzheimer's disease

BACKGROUND

To interpret changes of muscle strength in older adults with Alzheimer's disease (AD), determining the reliability of outcome measures is necessary. Therefore, the purpose of the present study was to investigate the relative and absolute intra-rater reliability of concentric isokinetic measures of the knee and ankle muscle strength in community-dwelling older adults without and with AD in the mild and moderate stages.

METHODS

A methodological study was conducted. The participants were submitted to two isokinetic evaluations with an interval of three to seven days. The evaluations consisted of knee extension and flexion at 60°/s (five repetitions) and 180°/s (15 repetitions) and plantar flexion and dorsiflexion of the ankle at 30°/s (five repetitions). The measures of interest were peak torque, average peak torque and total work. The intraclass correlation coefficient two-way mixed model of a single-measure (ICC_3,1), standard error of measurement (SEM) and minimal detectable change at the 95% confidence interval (MDC₉₅) were calculated. The ICC_3,1 was interpreted based on Munro's classification. Standard error of measurement and MDC₉₅ were analyzed in absolute and relative values (percentage of error [SEM%] and change [MDC₉₅%]).

RESULTS

A total of 62 older adults were included and allocated to the three groups: mild-AD (n = 22, 79.9 years, 15 female and seven male), moderate-AD (n = 20, 81.6 years, 15 female and five male) and without-AD (n = 20, 74.3 years, 10 female and seven male). The ICCs_3,1 of the measures of knee were high/very high in the three groups (0.71-0.98). The ICCs_3,1 of the measures of ankle were high/very high in the mild-AD group (0.78-0.92), moderate/high/very high in the moderate-AD group (0.63-0.93) and high/very high in the group without-AD (0.84-0.97). The measurements of knee extensors at 60°/s, knee extensors (peak torque and total work), with the exception of peak torque in the mild-AD group, and flexors (average peak torque) at 180°/s, and ankle dorsiflexors at 30°/s had the lowest of SEM% and MDC95% in the three groups.

CONCLUSION

Concentric isokinetic measures are reliable for the assessment of knee and ankle muscle strength in community-dwelling older adults without and with AD in the mild and moderate stages.

Lower Limb Extension Power is Associated With Slope Walking Joint Loading Mechanics in Older Adults

Fall-related injuries are associated with muscle weakness and common during slope walking in older adults. However, no study has evaluated the relationship between muscle weakness, measured by maximal lower limb extension power, and older adults' ability to navigate slope walking for a better understanding of fall prevention. Therefore, the purpose of this study was to investigate the association between maximal lower limb extension power and joint mechanics during slope walking. Fifteen healthy older adults were tested. Lower limb extension power was measured using the Leg Extension Power Rig. Kinematic and kinetic analysis was performed during level (0°), incline (10°), and decline (10°) slope walking. Greater maximal lower limb extension power was significantly (p < .050; Cohen's f2 > 0.35) associated with multiple kinetic and kinematic joint mechanic variables across stance phase of the gait cycle during level, incline, and decline walking. These findings will allow clinicians to better educate patients and develop interventions focused on fall prevention and improving functional mobility in older adults.

Development of a clinical prediction rule to identify physical activity after total hip arthroplasty

OBJECTIVE

To develop clinical prediction rule (CPR) of physical activity at 1-year after total hip arthroplasty (THA).

DESIGN

Retrospective cohort study.

SETTING

University hospital with orthopedic surgery.

PARTICIPANTS

The study group included 321 patients (56 men) who underwent primary THA.

INTERVENTION

Not applicable.

MAIN OUTCOMES MEASURES

The data collected included age, body mass index, clinical score from the questionnaires, hip pain, range of motion, muscle strength, and Physical functions (10-Meter Walk Test, Timed Up and Go test and Sit-to-stand). Patients were classified into sufficient and insufficient activity groups based on their University of California, Los Angeles (UCLA) activity score 1 year after THA. Variables measured preoperatively and at 3 weeks postoperatively were analyzed using univariate and multivariate methods to derive CPR for physical activity.

RESULTS

A CPR was developed using the following five factors and cut-offs: age, ≤70.5 years; preoperative UCLA activity score, ≥3.5; preoperative hip abduction strength, ≥0.54 Nm/kg; preoperative knee extension strength, ≥1.04 Nm/kg; and 10-Meter Walk Test, ≤8.49 s at 3 weeks after surgery. The presence of four of the five factors predicted a sufficient physical activity level at 1-year, with a positive likelihood ratio of 5.94 and probability of 85.4%. The presence of five predictor variables increased the probability of sufficient physical activity after THA to 94.7%.

CONCLUSION

This study developed a CPR for physical activity at 1-year after THA. Having four or more of the five measurements were useful indicators for predicting of physical activity at 1 year postoperatively.

Use of the activities and participation profile to assess the functioning of physically inactive elderly

Abstract Introduction: Physical inactivity negatively impacts the functional status of the elderly during aging. Objective: To describe the activity and participation profile of physically inactive elderly and to investigate associated factors. Methods: A cross-sectional study with physically inactive elderly, aged ≥ 60 years, both sexes, with good cognitive function and independent gait. Personal factors, clinical history, history of falls in the last year, and identification of activity and participation profiles were investigated. Nonparametric statistical tests (SPSS 20.0) were performed, considering p < 0.05 significant. Results: The elderly (n = 36) had a mean age of 72.5 years (±7.7). Most were women (78%), with one to four years of education (69%), retired (72%), referring episodes of falling (58%) and affected by two to four comorbidities (53%). In the activities and participation profile, most of the physically inactive elderly presented mild problems for: crawling, kneeling, squatting, walking long distances, walking on different surfaces, walking around obstacles, climbing, and using public transportation. However, kneeling, squatting, walking on different surfaces, and climbing represented higher percentages of elderly who presented some problem. The advancement of age (p = 0.045), female sex (p = 0.022), episodes of falls (p = 0.037), and comorbidities (p = 0.031) were identified as factors that can impact functioning. Conclusion: The physically inactive elderly presented a mild problem in activities and participation items that are more related to strength and walking. Elderly aged over 70, female, with episodes of falls and comorbidities were significantly associated with reduced or impaired functioning.

Uso do perfil de atividades e participação para avaliação da funcionalidade de idosos inativos fisicamente

Resumo Introdução: A inatividade física impacta negativamente a funcionalidade dos idosos durante o envelhecimento. Objetivo: Descrever o perfil de atividade e participação de idosos inativos fisicamente e investigar fatores associados. Métodos: Estudo transversal com idosos inativos fisicamente, ≥ 60 anos, ambos os sexos, boa função cognitiva e independentes na marcha. Foram investigados fatores pessoais, história clínica, histórico de quedas no último ano e identificação do perfil de atividade e participação. Foram realizados testes estatísticos não paramétricos (SPSS 20.0), considerando p < 0,05. Resultados: Os idosos (n = 36) apresentaram média de 72,5 anos (± 7,7). A maioria era mulher (78%), com escolaridade de um a quatro anos de estudo (69%), aposentados (72%), referindo episódios de queda (58%) e acometidos por duas a quatro comorbidades (53%). No perfil de atividades e participação, a maioria dos idosos inativos fisicamente apresentaram problema leve para os itens: engatinhar, ajoelhar-se, agachar-se, andar longas distâncias, andar sobre superfícies diferentes, andar desviando-se de obstáculos, subir e utilizar transporte público. Entretanto, ajoelhar-se, agachar-se, andar sobre superfícies diferentes e subir compreendem maiores percentuais de idosos que apresentaram algum problema. Idade avançada (p = 0,045), sexo feminino (p = 0,022), episódios de quedas (p = 0,037) e presença de comorbidades (p = 0,031) foram identificados como fatores que podem impactar na funcionalidade. Conclusão: Idosos inativos fisicamente apresentaram problema leve nos itens das atividades e participação que estão mais relacionados à força e ao andar. Idosos com mais de 70 anos, do sexo feminino, com presença de episódios de quedas e de comorbidades, apresentaram associação significativa com a funcionalidade reduzida ou prejudicada.

Effect of dietary nitrate on human muscle power: a systematic review and individual participant data meta-analysis

BACKGROUND

Previous narrative reviews have concluded that dietary nitrate (NO3-) improves maximal neuromuscular power in humans. This conclusion, however, was based on a limited number of studies, and no attempt has been made to quantify the exact magnitude of this beneficial effect. Such information would help ensure adequate statistical power in future studies and could help place the effects of dietary NO3- on various aspects of exercise performance (i.e., endurance vs. strength vs. power) in better context. We therefore undertook a systematic review and individual participant data meta-analysis to quantify the effects of NO3- supplementation on human muscle power.

METHODS

The literature was searched using a strategy developed by a health sciences librarian. Data sources included Medline Ovid, Embase, SPORTDiscus, Scopus, Clinicaltrials.gov , and Google Scholar. Studies were included if they used a randomized, double-blind, placebo-controlled, crossover experimental design to measure the effects of dietary NO3- on maximal power during exercise in the non-fatigued state and the within-subject correlation could be determined from data in the published manuscript or obtained from the authors.

RESULTS

Nineteen studies of a total of 268 participants (218 men, 50 women) met the criteria for inclusion. The overall effect size (ES; Hedge's g) calculated using a fixed effects model was 0.42 (95% confidence interval (CI) 0.29, 0.56; p = 6.310 × 10- 11). There was limited heterogeneity between studies (i.e., I2 = 22.79%, H2 = 1.30, p = 0.3460). The ES estimated using a random effects model was therefore similar (i.e., 0.45, 95% CI 0.30, 0.61; p = 1.064 × 10- 9). Sub-group analyses revealed no significant differences due to subject age, sex, or test modality (i.e., small vs. large muscle mass exercise). However, the ES in studies using an acute dose (i.e., 0.54, 95% CI 0.37, 0.71; p = 6.774 × 10- 12) was greater (p = 0.0211) than in studies using a multiple dose regimen (i.e., 0.22, 95% CI 0.01, 0.43; p = 0.003630).

CONCLUSIONS

Acute or chronic dietary NO3- intake significantly increases maximal muscle power in humans. The magnitude of this effect-on average, ~ 5%-is likely to be of considerable practical and clinical importance.

Dose-Response Effect of Dietary Nitrate on Muscle Contractility and Blood Pressure in Older Subjects: A Pilot Study

We have recently demonstrated that dietary nitrate, a source of nitric oxide (NO) via the nitrate → nitrite → NO enterosalivary pathway, can improve muscle contractility in healthy older men and women. Nitrate ingestion has also been shown to reduce blood pressure in some, but not all, studies of older individuals. However, the optimal dose for eliciting these beneficial effects is unknown. A pilot randomized, double-blind, placebo-controlled crossover study was therefore performed to determine the effects of ingesting 3.3 mL/kg of concentrated beetroot juice containing 0, 200, or 400 µmol/kg of nitrate in 9 healthy older subjects (mean age 70 ± 1 years). Maximal knee extensor power (Pmax) and speed (Vmax) were measured ~2.5 hours after nitrate ingestion using isokinetic dynamometry. Blood pressure was monitored periodically throughout each study. Pmax (in W/kg) was higher (p < .05) after the lower dose (3.9 ± 0.4) compared to the placebo (3.7 ± 0.4) or higher dose (3.7 ± 0.4). Vmax (in rad/s) also tended to be higher (p = .08) after the lower dose (11.9 ± 0.7) compared to the placebo (10.8 ± 0.8) or higher dose (11.2 ± 0.8). Eight out of 9 subjects achieved a higher Pmax and Vmax after the lower versus the higher dose. These dose-related changes in muscle contractility generally paralleled changes in breath NO levels. No significant changes were found in systolic, diastolic, or mean arterial blood pressure. A lower dose of nitrate increases muscle speed and power in healthy older individuals, but these improvements are lost at a higher dose. Blood pressure, on the other hand, is not reduced even with a higher dose.