Effect of leg muscle contraction velocity on functional performance in older men and women

Effects of High-Velocity Versus Low-Velocity Resistance Training on Muscle Echo Intensity in Healthy Young Women: A Randomized Controlled Trial

BACKGROUND

Improving muscle quality to prevent and treat muscle dysfunction is critical. However, effective measures to improve muscle quality remain poorly understood. We investigated the effects of high- and low-velocity resistance training (RT) on muscle quality, mass, and function before and after an 8-week intervention.

HYPOTHESIS

High-velocity RT would improve muscle quality more effectively than low-velocity RT.

STUDY DESIGN

Randomized controlled trial.

LEVEL OF EVIDENCE

Level 1.

METHODS

A total of 33 healthy young women (23.1 ± 2.2 years) were assigned randomly to high-velocity (n = 16) or low-velocity (n = 17) groups. Both groups underwent concentric knee extension RT with a 60% 1-repetition maximum (1RM) load, performing 10 repetitions of 4 sets, 3 times per week for 8 weeks. The high-velocity group was instructed to complete each repetition as quickly as possible (mean repetition duration of 0.5 seconds), while the low-velocity group was required to execute each repetition in 3 seconds. Before and after the 8-week intervention, quadriceps femoris echo intensity (EI), muscle thickness (MT), isokinetic peak torque (60 and 300 deg/s), rate of velocity development (RVD) at 300 deg/s, and 1RM were assessed. Split-plot factorial design analysis of variance was used to compare the group × time interaction.

RESULTS

A group×time interaction was observed for EI (P < 0.01). Only the high-velocity group showed a significant reduction in EI after the intervention. MT revealed a main effect of time (P < 0.01), with both groups significantly increasing MT. RVD showed a group × time interaction (P < 0.05), with significant increase only in the high-velocity group. Isokinetic peak torque and 1RM showed main effects of time (P < 0.01), with significant increases in both groups.

CONCLUSION

High-velocity RT may be superior to low-velocity RT in enhancing muscle quality and RVD.

CLINICAL RELEVANCE

These results emphasize the importance of RT velocity for muscle quality improvement.

Power-oriented resistance training combined with high-intensity interval training in pre-frail and frail older people: comparison between traditional and cluster training set configurations on the force-velocity relationship, physical function and frailty

OBJECTIVES

To analyse the force-velocity relationship changes in response to two different training programmes differing in the set configuration (cluster vs. traditional), and their impact on physical function and frailty in pre-frail and frail older adults.

METHODS

43 pre-frail and frail (Frailty Phenotype ≥ 1 criteria) older adults (81.4 ± 5.1 years) participated in this study. Participants were assigned to cluster (CT; n = 10; 10-s intra-set rest), traditional (TT; n = 13; no intra-set rest) or control (CON; n = 20) groups. Force-velocity relationship (F0, V0 and Pmax), physical function (Short Physical Performance Battery, SPPB) and frailty (Frailty Phenotype, FP) were assessed at baseline and after the training programme.

RESULTS

Both CT and TT groups showed similar improvements in Pmax after training (CT =  + 36.7 ± 34.2 W; TT =  + 33.8 ± 44.6 W; both p < 0.01). V0 was improved by both CT (+ 0.08 ± 0.06 m s-1; p < 0.01), and TT (+ 0.07 ± 0.15 m s-1, p > 0.05). F0 remained unchanged in CT (+ 68.6 ± 224.2 N, p > 0.05) but increased in TT (+ 125.4 ± 226.8 N, p < 0.05). Finally, SPPB improved in both training conditions (CT =  + 2.3 ± 1.3 points; TT =  + 3.0 ± 1.2 points; both p < 0.05) and in the CON group (+ 0.9 ± 1.4 points, p < 0.05). CT and TT reduced their FP (CT = - 1.1 criteria; TT = - 1.6 criteria; both p < 0.01), while no changes were observed in the CON group (- 0.2 criteria, p = 0.38).

CONCLUSIONS

Both training methods were equally effective for improving Pmax, physical function and reducing frailty in pre-frail and frail older people. TT may be effective for improving both force and velocity parameters, while CT may be effective for improving velocity parameters alone, although further research is required to confirm these findings.

Effects of exercise prehabilitation on muscle atrophy and contractile properties in hindlimb-unloaded rats

INTRODUCTION/AIMS

Effective strategies for rapid recovery after surgery are needed. Therefore, we investigated the effects of exercise prehabilitation (EP) and hindlimb unloading (HU) on muscle loss and contractility.

METHODS

Twenty-two Sprague-Dawley rats (12 wk old) were divided into normal control (NCON, n = 5), hindlimb unloading control (HCON, n = 10), and exercise prehabilitation followed by hindlimb unloading (Ex-preH, n = 7) groups. Ex-PreH performed exercise training for 14 days before hindlimb unloading for 14 days. Body composition was evaluated, along with muscle strength and function. The soleus (SOL) and extensor digitorum longus (EDL) muscle contractile properties were analyzed at the whole-muscle level. The titin concentration and myosin heavy chain (MHC) type composition were analyzed.

RESULTS

There were no effects of Ex-preH on total mass, lean mass, or muscle weight. Physical function was significantly higher in the Ex-preH group than in the HCON group (39.5° vs. 35.7°). The SOL twitch force (19.6 vs. 7.1 mN/m2 ) and specific force (107.3 vs. 61.2 mN/m2 ) were greater in Ex-preH group than in HCON group. EDL shortening velocity was higher in Ex-preH group than in HCON group (13.2 vs. 5.0 FL/s). The SOL full-length titin level was higher in Ex-preH group than in HCON group.

DISCUSSION

Exercise prehabilitation did not prevent muscle mass loss followed by muscle wasting, although it minimized the reduction of physical function. Therefore, exercise prehabilitation should be considered for rapid functional recovery after disuse due to surgery and injuries.

Evaluation of sex-based differences in resistance exercise training-induced changes in muscle mass, strength, and physical performance in healthy older (≥60 y) adults: A systematic review and meta-analysis

The objective of this systematic review and meta-analysis was to determine if there are sex-based differences in adaptations to resistance exercise training in healthy older adults. Following the screening process, data from 36 studies comparing older males and females (602 males; 703 females; ≥60 years of age) for changes in skeletal muscle size, muscle strength, and/or physical performance following the same resistance exercise training intervention were extracted. Mean study quality was 16/29 (modified Downs and Black checklist), considered moderate quality. Changes in absolute upper-body (Effect Size [ES] = 0.81 [95% CI 0.54, 1.09], P < 0.001), and lower-body (ES = 0.40 [95% CI 0.24, 0.56], P < 0.001) strength were greater in older males than females. Alternatively, changes in relative upper-body (ES = -0.46 [95% CI -0.77, -0.14], P < 0.01), and lower-body (ES = -0.24 [95% CI -0.42, -0.06], P < 0.01) strength were greater in older females than males. Changes in absolute, but not relative, whole-body fat-free mass (ES = 0.18 [95% CI 0.04, 0.33], P < 0.05) were greater in older males than females. There were no sex-based differences for absolute or relative changes in limb muscle size, muscle fiber size, or physical performance.

Effects of Power Training on Functional Capacity Related to Fall Risk in Older Adults: A Systematic Review and Meta-analysis

OBJECTIVE

Functional capacity is 1 of the main risk factors for falls among older adults. The aim of this systematic review and meta-analysis was to determine the effect of power training on functional capacity test (FCT) related to fall risk in older adults.

DATA SOURCES

Systematic searches were conducted in 4 databases, including PubMed, Web of Science, Scopus, and SPORTDiscus, from inception to November 2021.

STUDY SELECTION

Randomized controlled trials (RCTs) assessing the effect of power training on functional capacity compared with another type of training program or control group in older adults with the ability to exercise independently.

DATA EXTRACTION

Two independent researchers evaluated eligibility and used the PEDro scale to assess risk of bias. The information extracted was related to article identification (authors, country and year of publication), participant characteristics (sample, sex, and age), strength training protocols (exercises/intensity/weeks), and the outcome of the FCT used related to fall risk. The Cochran Q statistic and I2 statistics was used to assess heterogeneity. Random-effects model were conducted to pool the effect sizes expressed as mean differences (MD).

DATA SYNTHESIS

Twelve studies (478 subjects) were selected for systematic review. A meta-analysis comprised 6 studies (217 subjects) where the outcome measure was the 30-second Sit to Stand (30s-STS) test, and another comprised 4 studies (142 subjects) where the outcome measure was the timed Up and Go (TUG) test. There was an improvement in performance in favor of the experimental group in both the TUG subgroup (MD -0.31 s; 95% CI -0.63, 0.00 s; P=.05), and the 30s-STS subgroup (MD 1.71 reps; 95% CI -0.26, 3.67 reps; P=.09).

CONCLUSIONS

In conclusion, power training increases functional capacity related to fall risk further than other types of exercise in older adults.

Maximum knee extension velocity without external load is a stronger determinant of gait function than quadriceps strength in the early postoperative period following total knee arthroplasty

OBJECTIVE

Quadriceps weakness is considered the primary determinant of gait function after total knee arthroplasty (TKA). However, many patients have shown a gap in improvement trends between gait function and quadriceps strength in clinical situations. Factors other than quadriceps strength in the recovery of gait function after TKA may be essential factors. Because muscle power is a more influential determinant of gait function than muscle strength, the maximum knee extension velocity without external load may be a critical parameter of gait function in patients with TKA. This study aimed to identify the importance of knee extension velocity in determining the gait function early after TKA by comparing the quadriceps strength.

METHODS

This prospective observational study was conducted in four acute care hospitals. Patients scheduled for unilateral TKA were recruited (n = 186; age, 75.9 ± 6.6 years; 43 males and 143 females). Knee extension velocity was defined as the angular velocity of knee extension without external load as quickly as possible in a seated position. Bilateral knee function (knee extension velocity and quadriceps strength), lateral knee function (pain and range of motion), and gait function (gait speed and Timed Up and Go test (TUG)) were evaluated before and at 2 and 3 weeks after TKA.

RESULTS

Both bilateral knee extension velocities and bilateral quadriceps strengths were significantly correlated with gait function. The knee extension velocity on the operation side was the strongest predictor of gait function at all time points in multiple regression analysis.

CONCLUSION

These findings identified knee extension velocity on the operation side to be a more influential determinant of gait function than impairments in quadriceps strength. Therefore, training that focuses on knee extension velocity may be recommended as part of the rehabilitation program in the early postoperative period following TKA.

TRIAL REGISTRATION

UMIN Clinical Trials Registry (UMIN-CTR) UMIN000020036.

Efficacy and evaluation of therapeutic exercises on adults with Parkinson's disease: a systematic review and network meta-analysis

Background

Exercises are an effective treatment in Parkinson’s disease (PD), but there is still controversy over which types should be used. We aimed to compare and rank the types of exercise that improve PD symptoms by quantifying information from randomised controlled trials.

Methods

We performed a systematic review and network meta-analysis and searched PubMed, MEDLINE, Embase, PsycINFO, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and China National Knowledge Infrastructure (CNKI) from their inception date to June 30, 2022. We included randomized controlled trials of 24 types of exercise for the interventional treatment of adults (≥ 50 years old) with PD. Effect size measures were standardized mean differences (SMDs) with 95% credible intervals (CrIs). The confidence of evidence was examined using Confidence in Network Meta-Analysis (CINeMA).

Results

We identified 10 474 citations and included 250 studies involving 13 011 participants. Results of NMA showed that power training (PT) had the best benefits for motor symptoms compared with the control group (CON), with SMDs (95% CrI) (-1.46, [-2.18 to -0.74]). Body weight support treadmill training (BWS_TT) showed the best improvement in balance (1.55, [0.72 to 2.37]), gait velocity (1.15 [0.57 to 1.31]) and walking distance (1.96, [1.18 to 2.73]), and robotic assisted gait training (RA_GT) had the most benefits for freezing of gait (-1.09, [-1.80 to -0.38]). For non-motor symptoms, Dance showed the best benefits for depression (-1.71, [-2.79 to -0.73]). Only Yoga significantly reduced anxiety symptom compared with CON (-0.53, [0.96 to -0.11]). Only resistance training (RT) significantly enhanced sleep quality and cognition (-1.42, [-2.60 to -0.23]; 0.51, [0.09 to 0.94]). For muscle strength, PT showed the best advance (1.04, [0.64 to 1.44]). For concern of falling, five types of exercise were more effective than CON.

Conclusions

There is low quality evidence that PT, Yoga, BWS_TT, Dance, and RT are the most effective treatments, pending outcome of interest, for adults with PD.

Trial registration

PROSPERO (CRD42021220052).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03510-9.

Examination of the Impact of Strength and Velocity of the Knee and Ankle on Gait Speed in Community-Dwelling Older Adults

The muscle strength of the knee extension and plantarflexion plays a crucial role in determining gait speed. Recent studies have shown that no-load angular velocity of the lower limb joints is essential for determining gait speed. However, no reports have compared the extent to which lower limb functions, such as knee extension strength, knee extension velocity, plantarflexion strength, and plantarflexion velocity, impact gait speed in a single study. Therefore, this study aimed to examine the relative importance of maximum strength and no-load angular velocity on gait speed. Overall, 164 community-dwelling older adults (72.9 ± 5.0 years) participated in this study. We measured the gait speed and lower limb function (the strength and velocity of knee extension and plantarflexion). Strength was measured with a hand-held dynamometer, and velocity with a gyroscope. A multiple regression analysis was performed with gait speed as the dependent variable and age, sex, and lower-limb function as independent variables. Plantarflexion velocity (β = 0.25) and plantarflexion strength (β = 0.21) were noted to be significant predictors of gait speed. These findings indicate that no-load plantarflexion velocity is more important than the strength of plantarflexion and knee extensions as a determinant of gait speed, suggesting that improvement in plantarflexion velocity may increase gait speed.

Functional performance of older adults: A comparison between men and women

The objective of this study was to compare the functional performance of community-dwelling older adults of both sexes and investigate the possible mediation aspects that may influence the sex differences regarding socioeconomic and anthropometric characteristics, health status, and quadriceps muscle strength. 233 Brazilian older adults were assessed, and men's and women's sociodemographic data, physical activity level, quadriceps muscle strength, functional performance (gait speed and the SPPB), and history of falls were compared. Sex differences in functional performance were observed even after statistically adjusting the model (age, body mass, income, physical activity level, and occurrence of falls). When quadriceps muscle strength was included in the adjusted model, the sex difference remained only for gait speed. When stature was included in the adjusted model, the sex difference in gait speed disappeared. Our results suggest that the sex difference in functional performance assessed by the SPPB can be explained due to the fact that men are stronger than women. In addition, the sex difference regarding gait speed was explained by the sex difference in stature. Public actions that encourage older women to practice physical activities that promote increased muscle strength can positively interfere with their best functional performance for as long as possible.

Validity, reliability, and measurement error of a sit-to-stand power test in older adults: A pre-registered study

OBJECTIVES

Lower body power declines with age and is associated with decreased physical function in older adults. However, the majority of the tools available to measure power are expensive and require considerable space and expertise to operate. The purpose of this study was to assess the validity, reliability, and measurement error of a sit-to-stand power test (STSp) to assess lower body power.

METHODS

51 community-dwelling adults, 65 years or older, completed a power test using a pneumatic leg press (LP), the Short Physical Performance Battery (SPPB) that includes a test of balance, usual walking speed, and chair stand tests; Timed Up and Go (TUG) test at both usual and fast paces, and Patient-Reported Outcome Measures (PROMs). A two-week test-retest assessed the reliability in 36 participants. The study hypotheses and analysis were pre-registered prior to data collection and statistical analyses were blinded.

RESULTS

The mean age was 71.3 years, with 63% females, and an average SPPB score of 10.6 (median = 12). STSp peak power was strongly correlated with LP (r = 0.90, 95% CI (0.82, 0.94). As hypothesized, the STSp peak power showed similar or higher correlations with physical function tests relative to LP peak power: SPPB (0.41 vs. 0.29), chair stand test (-0.44 vs. -0.35), TUG test at usual pace (-0.37 vs. -0.29) and fast pace (-0.41 vs. -0.34) and balance (0.33 vs. 0.22), but not for mobility (0.34 vs. 0.38) and function (0.41 vs. 0.48) questionnaire. For discriminant validity, as hypothesized, males showed higher STSp peak power compared to females (Δ = 492 W, p < .001, Cohen's d = 2.0). Test-retest assessment yielded an intraclass correlation coefficient of 0.96 and a standard error of measurement of 70.4 W. No adverse events were reported or observed for both tests.

CONCLUSION

The STSp showed adequate validity and reliability in measuring lower body power in community-dwelling older adults. The test is quick, relatively inexpensive, safe, and portable and thus should be considered for use in aging research.

Muscle Function Tests as Supportive Outcome Measures for Performance-Based and Self-Reported Physical Function in Patients With Knee Osteoarthritis: Exploratory Analysis of Baseline Data From a Randomized Trial

Holm, PM, Kemnitz, J, Bandholm, T, Wernbom, M, Schrøder, HM, and Skou, ST. Muscle function tests as supportive outcome measures for performance-based and self-reported physical function in patients with knee osteoarthritis: Exploratory analysis of baseline data from a randomized trial. J Strength Cond Res XX(X): 000-000, 2020-Uncertainty on the role of muscle function in relation to physical function in knee osteoarthritis (KOA) persists. This study aimed to assess the associations between muscle function and performance-based and self-reported physical function in patients with KOA. Physical function in 80 subjects with symptomatic and radiographic KOA was assessed using 40-m fast-paced walk, 30-second chair stand, 9-step stair climb tests, and the subscale activities of daily living from the Knee injury and Osteoarthritis Outcome Score (KOOS-ADL). Measurements of muscle function included leg extension (LE) power, knee extension (KE) torque, and estimated leg press one repetition maximum (LP RM). Associations were investigated using multivariable hierarchical linear regressions adjusted for age, sex, body mass index, self-reported physical activity, and thigh muscle lean area. Leg extension power was significantly associated with 40-m walk, stair climb, and 30-second chair stand, explaining 18, 8, and 3% of additional variance, respectively. Knee extension torque explained 13, 7, 17, and 7% of additional variance in the 40-m walk, stair climb, 30-second chair stand, and KOOS-ADL, respectively. Leg press one repetition maximum explained 11% of additional variance in the 30-second chair stand. In conclusion, LE power was the best explanatory variable for performance on the 40-m walk and stair climb tests, whereas KE torque best explained chair stand performance. Only KE torque was associated with KOOS-ADL. Our results highlight the importance of selecting supportive muscle function tests based on the specific physical function and suggest that other factors may be more important for certain physical function outcomes. Level of significance p < 0.05. Trial identifier: NCT03215602.

Quadriceps muscle properties in rheumatoid arthritis: insights about muscle morphology, activation and functional capacity

BACKGROUND

Rheumatoid arthritis (RA) is an inflammatory and chronic autoimmune disease that leads to muscle mass loss and functional capacity impairment, potentiated by physical inactivity. Despite evidences demonstrate neuromuscular impairments in RA patients, aging effects may have masked the results of similar previous studies. The aim of study was to verify (i) the effects of RA on functional capacity and muscle properties in middle-aged patients and (ii) the association between age, clinical characteristics, quadriceps muscle properties and functional capacity.

METHODS

Thirty-five RA women and 35 healthy age-matched women were compared with the following outcomes: (i) physical activity level through the International Physical Activity Questionnaire (IPAQ); (ii) timed-up and go (TUG) test; (iii) isometric knee extensor muscular strength; and (iv) vastus lateralis muscle activation and muscle architecture (muscle thickness, pennation angle and fascicle length) during an isometric test. An independent Student t-test and partial correlation (controlled by physical activity levels) were performed, with p < 0.05.

RESULTS

Compared with healthy women, RA presented (i) lower physical activity level (- 29.4%; p < 0.001); (ii) lower isometric knee extensor strength (- 20.5%; p < 0.001); (iii) lower TUG performance (- 21.7%; p < 0.001); (iv) smaller muscle thickness (- 23.3%; p < 0.001) and pennation angle (- 14.1%; p = 0.011). No differences were observed in muscle activation and fascicle length. Finally, the correlation demonstrated that, with exception of TUG, muscle strength and muscle morphology were not associated with age in RA, differently from healthy participants.

CONCLUSION

Middle-aged RA patients' impairments occurred due to the disease independently of the aging process, except for functional capacity. Physical inactivity may have potentiated these losses.

Associations between novel jump test measures, grip strength, and physical performance: the Osteoporotic Fractures in Men (MrOS) Study

BACKGROUND/AIMS

Weight-bearing jump tests measure lower extremity muscle power, velocity, and force, and may be more strongly related to physical performance than grip strength. However, these relationships are not well described in older adults.

METHODS

Participants were 1242 older men (mean age 84 ± 4 years) in the Osteoporotic Fractures in Men (MrOS) Study. Jump peak power (Watts/kg body weight), force (Newton/kg body weight) at peak power, and velocity (m/s) at peak power were measured by jump tests on a force plate. Grip strength (kg/kg body weight) was assessed by hand-held dynamometry. Physical performance included 400 m walk time (s), 6 m usual gait speed (m/s), and 5-repeated chair stands speed (#/s).

RESULTS

In adjusted Pearson correlations, power/kg and velocity moderately correlated with all performance measures (range r = 0.41-0.51; all p < 0.001), while correlations for force/kg and grip strength/kg were weaker (range r = 0.20-0.33; all p < 0.001). Grip strength/kg moderately correlated with power/kg (r = 0.44; p < 0.001) but not velocity or force/kg. In adjusted linear regression with standardized βs, 1 SD lower power/kg was associated with worse: 400 m walk time (β = 0.47), gait speed (β = 0.42), and chair stands speed (β = 0.43) (all p < 0.05). Associations with velocity were similar (400 m walk time: β = 0.42; gait speed: β = 0.38; chair stands speed: β = 0.37; all p < 0.05). Force/kg and grip strength/kg were more weakly associated with performance (range β = 0.18-0.28; all p < 0.05).

CONCLUSIONS/DISCUSSION

Jump power and velocity had stronger associations with physical performance than jump force or grip strength. This suggests lower extremity power and velocity may be more strongly related to physical performance than lower extremity force or upper extremity strength in older men.

Validity of various portable devices to measure sit-to-stand velocity and power in older adults

BACKGROUND

Movement velocity and power in a single STS are related to functional performance in older adults. Identifying accessible tools that provide valid measures of STS velocity/power would allow practitioners to evaluate physical function in clinical settings where time, space and finances are limited.

RESEARCH QUESTION

Does a linear position transducer (LPT), iPhone application (App), and inertial measurement unit (IMU) obtain valid measurements of velocity and power during a single STS compared with 3D motion capture?

METHODS

Twenty-seven community-dwelling older adults aged ≥60 years completed a single STS test with mean velocity and power simultaneously measured with 3D motion capture, an LPT, IMU and App. Acceptable validity was established if the Pearson correlation coefficient (r) was very high (≥0.7) and bias as a standardised effect size (ES) was small (<0.6). The relationship between STS velocity/power and 30s chair STS performance was also evaluated.

RESULTS

Measures of STS velocity obtained by the LPT (r = 0.94, ES = -0.21) and App (r = 0.89, ES = -0.19) were very highly valid when compared to 3D motion capture, and were very strongly related to 30s STS performance (r ≥0.74). The LPT (r = 0.87, ES = 0.13) and App (r = 0.74, ES = -0.12) also showed very high correlations and negligible bias for measuring STS power. Data collected by the IMU failed to meet our pre-determined threshold of acceptable validity for STS velocity (r = 0.72, ES = 1.00) or power (r = 0.61, ES = 0.34).

SIGNIFICANCE

The LPT and iPhone App, but not the IMU, are valid tools for measuring STS velocity and power in community-dwelling older adults. Clinicians can use STS velocity obtained by either the LPT or App as a simple and valid proxy for functional status, which could help identify patients at high-risk of incident disability.

Effect of a Multicomponent Home-Based Physical Therapy Intervention on Ambulation After Hip Fracture in Older Adults: The CAP Randomized Clinical Trial

IMPORTANCE

Disability persists after hip fracture in older persons. Current rehabilitation may not be sufficient to restore ability to walk in the community.

OBJECTIVE

To compare a multicomponent home-based physical therapy intervention (training) with an active control on ability to walk in the community.

DESIGN, SETTING, AND PARTICIPANTS

Parallel, 2-group randomized clinical trial conducted at 3 US clinical centers (Arcadia University, University of Connecticut Health Center, and University of Maryland, Baltimore). Randomization began on September 16, 2013, and ended on June 20, 2017; follow-up ended on October 17, 2017. Patients aged 60 years and older were enrolled after nonpathologic, minimal trauma hip fracture, if they were living in the community and walking without human assistance before the fracture, were assessed within 26 weeks of hospitalization, and were not able to walk during daily activities at the time of enrollment. A total of 210 participants were randomized and reassessed 16 and 40 weeks later.

INTERVENTIONS

The training intervention (active treatment) (n = 105) included aerobic, strength, balance, and functional training. The active control group (n = 105) received transcutaneous electrical nerve stimulation and active range-of-motion exercises. Both groups received 2 to 3 home visits from a physical therapist weekly for 16 weeks; nutritional counseling; and daily vitamin D (2000 IU), calcium (600 mg), and multivitamins.

MAIN OUTCOMES AND MEASURES

The primary outcome (community ambulation) was defined as walking 300 m or more in 6 minutes at 16 weeks after randomization. The study was designed to test a 1-sided hypothesis of superiority of training compared with active control.

RESULTS

Among 210 randomized participants (mean age, 80.8 years; 161 women [76.7%]), 197 (93.8%) completed the trial (187 [89.0%] by completing the 6-minute walk test at 16 weeks and 10 [4.8%] by adjudication of the primary outcome). Among these, 22 of 96 training participants (22.9%) and 18 of 101 active control participants (17.8%) (difference, 5.1% [1-sided 97.5% CI, -∞ to 16.3%]; 1-sided P = .19) became community ambulators. Seventeen training participants (16.2%) and 15 control participants (14.3%) had 1 or more reportable adverse events during the intervention period. The most common reportable adverse events reported were falls (training: 6 [5.7%], control: 4 [3.8%]), femur/hip fracture (2 in each group), pneumonia (training: 2, control: 0), urinary tract infection (training: 2, control: 0), dehydration (training: 0, control: 2), and dyspnea (training: 0, control: 2).

CONCLUSIONS AND RELEVANCE

Among older adults with a hip fracture, a multicomponent home-based physical therapy intervention compared with an active control that included transcutaneous electrical nerve stimulation and active range-of-motion exercises did not result in a statistically significant improvement in the ability to walk 300 m or more in 6 minutes after 16 weeks.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01783704.

The Roles of Sex and Physical Activity in Gait and Knee Extensor Function With Age

Older females experience higher rates of disability than males, potentially due to sex-specific differences in gait and muscle function. The authors evaluated the effects of age and physical activity (PA) on gait mechanics and knee extensor muscle function in males and females. Three groups of 20 individuals (each 10 females) participated: young (21-35 y) and highly and less active older (55-70 y) adults. Knee extensor strength and joint mechanics during preferred speed gait were collected before and after 30 minutes of walking. Age by sex and PA by sex interactions indicated older and less active older females had lower concentric knee extensor muscle power and larger hip extension moments than males. After 30 minutes of walking, older less active adults had larger decreases in knee extensor power than their highly active older counterparts, and older adults of both sexes had decreases in ankle dorsiflexion moments while young adults did not. These results suggest that older, particularly less active, adults are susceptible to knee extensor muscle fatigue from moderate activity. For older adults, high levels of PA may be necessary to preserve gait mechanics in response to a bout of exercise. This new information may be important for targeting interventions in at-risk older adults.

Rate of torque development and the risk of falls among community dwelling older adults in Japan

BACKGROUND

Rate of torque development (RTD) is defined as the slope of the torque-time curve obtained during an isometric contraction. Several studies have shown that RTD is lower in fallers than in nonfallers. However, these studies had small sample size and was not adjusted confounding factors.

RESEARCH QUESTION

Is RTD associated with falls history in healthy community dwelling older adults.

METHODS

This was cross-sectional study. In total, 122 participants aged ≥65 (mean, 71.3 ± 4.4) years were recruited for this study. We assessed RTD, muscle strength, functional capacity, and physical activity. We assessed RTD over the first 200 ms of the maximal isometric contraction, whereby the onset of contraction was deemed as the point at which torque had risen 4 Nm above the baseline. Differences between the 3 groups (no fall group, single fall group and multiple falls group) were examined using one-way analysis of variance or Kruskal-Wallis test. A post-hoc Bonferroni or Games-Howell test was used to assess the differences between the individual groups. A multivariate multinomial logistic model was built using the factors associated with the fall category.

RESULTS

RTD was significantly different between the no fall group and multiple falls group (P = 0.047). Similarly, RTD was significantly different between the single fall group and multiple falls group (P = 0.016). RTD was associated with both the no fall group and single fall group (odds ratio = 2.05, 95% confidence interval: 1.06-3.97, odds ratio = 2.45, 95% confidence interval: 1.20-4.98, respectively) in multinomial logistic regression.

SIGNIFICANCE

This is the first study to investigate the relationship between RTD and falls history in community-dwelling older adults in multivariate analysis. RTD is more strongly associated with falls history than other performance measures in community-dwelling elderly.

Preliminary study on the effects of movement velocity training of the upper limbs on gait ability in older adults: a nonrandomized controlled trial

Purpose: Movement velocity of the limbs or trunk plays an important determinant of gait speed in older adults. Movement velocity-focused training of the lower limbs or trunk has recently been shown to be an effective intervention to improve gait ability. Because movement velocities of various body regions are significantly correlated, movement velocity training of the upper limbs may also be effective for improving gait speed. Therefore, the purpose of this study was to investigate whether movement velocity training of the upper limbs in a seated position is effective for improving gait ability.

Patients and methods: This study was a nonrandomized controlled trial. The participants were older adults residing in geriatric health service facilities. They were assigned to the movement velocity training of the upper limbs group (n=26) or control group (n=15). The participants in the training group performed exercises (three times per week for 10 weeks) to move the upper limbs as quickly as possible. The outcomes were gait speed, movement velocity, and quadriceps strength. These measurements were performed preintervention and 4, 8, and 10 weeks after intervention.

Results: A significant time–group interaction was found for maximum gait speed and movement velocity of the upper limbs. Bonferroni post-hoc test showed significant improvement in gait speed between preintervention and 10 weeks after intervention in the training group. The movement velocity of the upper limbs was significantly improved between preintervention and 4, 8, and 10 weeks after intervention.

Conclusion: Movement velocity training of the upper limbs showed significant and clinically relevant improvements in maximum gait speed at 10 weeks after intervention. This training is a potentially useful intervention and can be safely performed.

Muscle power, contraction velocity and functional performance after stroke

OBJECTIVE

The goal of this study was to describe muscle function deficit in patients after stroke as well as to define the relationship between maximal muscle power (P_max ) and optimal shortening velocity (υ_opt ) with functional efficiency in stroke survivors.

MATERIAL AND METHODS

A total of 134 participants were enrolled in the study, including 67 patients after a stroke and 67 volunteers, matched for age and sex (controls). Functional performance was measured with the timed Up and Go test (TUG) and additionally with Rivermead Motor Assessment (RMA) and Barthel Index (BI) in stroke survivors. To assess P_max and υ_opt of the knee extensor muscles, a specially equipped Monark cycle ergometer was used.

RESULTS

The power generated by stroke survivors was 49.6% that of their peers and muscle contraction velocity was 65.5%. P_max /kg and υ_opt were associated with TUG outcomes in both groups. P_max /kg and υ_opt were associated with age in the control group, but not in patients after stroke. In multivariate analysis in patients after stroke, TUG was better predicted by P_max /kg or υ_opt than by the age. In stroke survivors, both P_max /kg and υ_opt were related to the BI and to the RMA total results. Both BI and RMA total were not determined by age.

CONCLUSIONS

Muscle power and muscle contraction velocity in patients who have had a stroke within three months have reduced markedly. These factors significantly affect functional performance. Muscle power and optimal shortening velocity are more important determinants of functional status than age in these stroke survivors.

Longitudinal comparison of low- and high-velocity resistance training in relation to body composition and functional fitness of older adults

BACKGROUND

Functional mobility disability affects more than one in five adults over 70 years and increases to 80% by 90 years. While negative changes in mobility are multifactorial, deleterious body composition changes contribute significantly. Resistance training alters the negative trajectory of physical function as well as increases lean mass among older adults. Recently, high-velocity (HV) resistance training has been indicated as an effective intervention to increase lean mass and functional performance.

AIMS

The present investigation compared body composition, physical function, and muscular strength changes between HV and LV resistance training programs.

METHODS

Participants > 65 years (n = 53) were randomly assigned to LV, HV, or active control (AC) group and participated in their respective intervention for 48 weeks.

RESULTS

Analysis of covariance revealed no significant body composition changes over time between groups (p > 0.05). Eight-foot up-and-go performance improved in the HV and AC groups (p < 0.05) with no change in the LV group (p > 0.05) over time. Muscular strength increased in both the LV and HV groups within the first 24 weeks, while only in the LV group, muscular strength continued to increase from 24 to 48 weeks (p < 0.05).

DISCUSSION

Resistance training appears to be an effective intervention for improving aspects of physical function and muscular strength; however, no significant changes in body composition were observed over the 48-week intervention.

CONCLUSION

Findings from the current investigation support use of resistance training for improving physical function among community-dwelling older adults.

An easy and safe training method for trunk function improves mobility in total knee arthroplasty patients: A quasi-randomized controlled trial

Objective

Total knee arthroplasty (TKA) is aimed mainly at reducing pain and restoring mobility. However, mobility deficits can persist even longer than 1 year. The trunk function and movement velocity of any region have been recently recognized to be critical for determining mobility in older people. Therefore, the main goal of this quasi-randomized trial is to clarify the effectiveness of a novel training method, the seated side tapping (SST) training, for improving mobility by focusing on movement velocity of trunk function in the short term after TKA.

Methods

SST training consists of side trunk movements repeated as quickly as possible in a seated position. All participants after TKA were randomly assigned to the SST training group (n = 37) or control training group (n = 38). The participants in the SST group performed SST training plus the standard rehabilitation program 5 days per week for 3 weeks after TKA, while the control group performed only the standard rehabilitation programs. The primary outcome was the effect of SST training on mobility, indicated by gait speed and the timed up and go test (TUG) time. Measurements were performed before and 1, 2, and 3 weeks after surgery.

Results

At all-time points, the patients in the SST group showed significantly better mobility, despite that knee function, represented by muscle strength, range of motion, and degree of pain at the knee joint, was similar in both groups. The difference in gait speed between the groups was >0.1 m/s at all time points, which is clinically significant.

Conclusion

SST training significantly improved patients’ mobility within 3 weeks after TKA, despite that no additional benefit was observed in knee function. The findings in this study indicate that SST training may be considered as a part of the rehabilitation program after TKA, although further evaluation of its long-term effectiveness is needed.

Trial registration

University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR; UMIN000027909).

Knee extension rate of torque development and peak torque: associations with lower extremity function

BACKGROUND

With aging, the ability to generate muscle force decreases, contributing to declines in physical functions such as walking. While most studies assess muscle force by peak torque, the rate of torque development (RTD) reflects a dynamic component of muscle performance that is important for physical function. Using data from the Baltimore Longitudinal Study of Aging, we assessed whether RTD adds significantly to peak torque in associations with lower extremity performance. If so, RTD may help identify weak older adults for screening and intervention.

METHODS

We assessed associations of RTD and peak torque with physical performance independent of demographics, BMI, body composition, and each other in 1089 Baltimore Longitudinal Study of Aging participants (49.7% women; aged 26 to 96 years; women, 64.0 ± 13.8 years; men, 68.4 ± 14.4 years). Peak torque was assessed by isometric and 30 deg/s isokinetic knee extension tests. Peak RTD was operationalized as the maximum torque-time slope among successive 50 ms epochs over the first 3 s of a test of knee extension isometric strength, with the knee joint positioned at 120 deg of flexion. A battery of lower extremity performance tests included gait speed during a 6 m walk at usual and fast pace (6 m usual and fast), time to complete a 400 m walk at fast pace (400 m), distance covered in a 2.5 min walk at normal pace (2.5 min), time to complete 5 and 10 chair stands, and two summary tests of lower extremity performance. Sex-stratified generalized linear regression models were adjusted for age, race, BMI, appendicular lean mass, and whole body fat mass.

RESULTS

In men, independent of either measure of peak torque and cofactors, RTD was a significant (P < 0.05) predictor of all lower extremity performance tests except the 400 m and 2.5 min walks. In women, independent of peak torque, RTD was only a significant independent correlate of the 6 m fast walk (P < 0.001).

CONCLUSIONS

RTD independently contributes to physical functions in men but less in women. The mechanisms underlying the sex difference are unclear and require further study.

High-Velocity Quadriceps Exercises Compared to Slow-Velocity Quadriceps Exercises Following Total Knee Arthroplasty: A Randomized Clinical Study

BACKGROUND AND PURPOSE

Despite improvement in pain and perceived function in older adults following total knee arthroplasty (TKA), objective outcome measures of muscular impairment and ambulatory function demonstrate significant deficits. Evidence suggests that quadriceps power may play a greater role in ambulatory function than measures of strength alone following TKA. The purpose of this study was to compare the effect of high-velocity (HV) quadriceps exercises with that of slow-velocity (SV) quadriceps exercises on functional outcomes and quadriceps power following TKA.

METHODS

This study was a randomized clinical study conducted in an outpatient physical therapy clinic. Twenty-one participants who were 4 to 6 weeks post unilateral TKA were randomly assigned to an HV or SV group. Participants performed an evidence-based standardized progressive resistance exercise program in addition to HV quadriceps exercises or SV quadriceps exercises. Participants attended 2 sessions per week for 8 weeks. Before and after the 8-week exercise intervention, participants completed a functional questionnaire, health survey, functional testing, and underwent quadriceps strength and power testing.

RESULTS

Both groups demonstrated improvements in ambulatory outcome measures, strength, speed, and power. The HV group demonstrated significantly greater improvements in distance walked and quadriceps strength than the SV group.

LIMITATIONS

These data should be considered preliminary because of a small sample size.

CONCLUSION

HV quadriceps exercises may be an effective rehabilitation strategy in conjunction with a standardized progressive resistance exercise program beginning 4 to 6 weeks after TKA.

Lower Quadriceps Rate of Force Development Is Associated With Worsening Physical Function in Adults With or at Risk for Knee Osteoarthritis: 36-Month Follow-Up Data From the Osteoarthritis Initiative

OBJECTIVE

To determine the association between quadriceps rate of force development (RFD) and decline in self-reported physical function and objective measures of physical performance.

DESIGN

Longitudinal cohort study.

SETTING

Community-based sample from 4 urban areas.

PARTICIPANTS

Osteoarthritis Initiative participants with or at risk for knee osteoarthritis, who had no history of knee/hip replacement, knee injury, or rheumatoid arthritis (N=2630).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Quadriceps RFD (N/s) was measured during isometric strength testing. Worsening physical function was defined as the minimal clinically important difference for worsening self-reported Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function subscale score, 20-m walk time, and repeated chair stand time over 36 months.

RESULTS

Compared with the slowest tertile of RFD, the fastest tertile had a lower risk for worsening of WOMAC physical function subscale score at 36-month follow-up, with an odds ratio (OR) of .68 (95% confidence interval [CI], .51-.92) after adjustment for age, sex, body mass index, depression, history of chronic diseases, and knee pain. In women, in comparison with the slowest tertile of RFD, the fastest tertile had a lower risk for worsening of WOMAC physical function subscale score at 36-month follow-up, with an adjusted OR of .57 (95% CI, .38-.86). This decreased risk did not reach statistical significance in men (OR, 0.81; 95% CI, 0.52-1.27). No statistically significant associations were detected between baseline RFD and walk or chair stand times.

CONCLUSIONS

Our results indicate that higher RFD is associated with decreased risk for worsening self-reported physical function but not with decreased risk for worsening of physical performance.

Measurement of muscle health in aging

Muscle health is a critical component in the struggle against physical frailty and the efforts to maintain metabolic health until the limit of chronological age. Consensus opinion is to evaluate muscle health in terms of muscle mass, strength and functional capability. There has been considerable variability in the components of muscle health which have been investigated in addition to variability in the tools of assessment and protocol for measurement. This is in stark contrast to the validated measurement of bone health across the adult life span. The purpose of this review was to identify indices of muscle mass, strength and functional capability most responsive to change with ageing and where possible to provide an estimate of the rate of change. We suggest lean tissue mass (LTM) or skeletal muscle (SM) is best evaluated from the thigh region due to its greater responsiveness to ageing compared to the whole body. The anterior compartment of the thigh region undergoes a preferential age-related decline in SM and force generating capacity. Therefore, we suggest that knee extensor torque is measured to represent the force generating capacity of the thigh and subsequently, to express muscle quality (strength per unit tissue). Finally, we suggest measures of functional capability which allow participants perform to a greater maximum are most appropriate to track age-related difference in functional capacity across the adult lifespan. This is due to their ability encompass a broad spectrum of abilities. This review suggests indices of muscular health for which reference ranges can be generated across the lifespan.

A modified seated side tapping test in which the arms are crossed also reflects gait function in community-dwelling elderly

[Purpose] Seated side tapping test (SST) performance is associated with mobility impairment in the elderly. Although this test was developed to assess trunk function, interpretation of its results may be confounded by the upper-limb movements in its protocol. Here, this study aimed to validate the association between trunk function and gait function by means of the Arms Crossed SST (AC-SST), a modified version of the SST in which the arms are crossed over the chest, to exclude the effects of the upper limbs. [Subjects and Methods] A total of 116 community-dwelling elderly people were enrolled in the study (mean age: 75.1 ± 5.5 yrs). Measurement categories were gait function (gait speed and TUG), lower extremity strength (knee extension and flexion strength), trunk muscle endurance (trunk extension and flexion endurance), and trunk function (SST and AC-SST). [Results] AC-SST performance significantly correlated with gait function items, as did SST performance. Moreover, AC-SST was one of the significant predictor variables of gait function selected in stepwise multiple regressions. [Conclusion] Gait function associated with performance on the AC-SST, a test of trunk function in which the effects of upper limb function were excluded, reinforcing the importance of trunk function to elderly mobility.

Knee extensor power asymmetry is unrelated to functional mobility of older adults

PURPOSE

To determine whether knee extensor power asymmetry limits functional mobility of older adults who possess muscle weakness.

METHODS

Knee extensor power was measured in 36 older men and women (76.0±7.6yr), for each leg, on an isokinetic dynamometer at 60, 180, and 300degs^-1 and power asymmetry was calculated as the percent difference in power between strong and weak legs, at each isokinetic velocity. 400-m walk, stair ascent, and five-repetition chair rise tests were performed to assess functional mobility. Pearson correlations were used to examine the relationship between weak leg power, strong leg power, power asymmetry, and 400-m walk time, stair ascent time, and chair rise time. Participants were then stratified into low power-high asymmetry (LP-HA), low power-low asymmetry (LP-LA), high power-high asymmetry (HP-HA), and high power-low asymmetry (HP-LA) groups who were compared for functional mobility.

RESULTS

Knee extensor power asymmetry was unrelated to 400-m walk time (r=0.16, p=0.180), stair ascent time (r=0.22, p=0.094), or chair rise time (r=0.03, p=0.437), whereas weak and strong leg powers were equally associated with 400-m time (r=-0.62, p<0.001; r=-0.62, p<0.001), stair ascent time (r=-0.55, p<0.001; r=-0.57, p<0.001), and chair rise time (r=-0.28, p=0.048; r=-0.31, p=0.032), respectively. Power asymmetry was lowest at 60degs^-1 (12%), and increased with contraction velocity (p=0.001) to 15% at 180degs^-1 and to 20% at 300degs^-1. LP-HA exhibited 26% slower 400-walk time than HP-LA (p=0.015) and 19% slower than HP-HA (p=0.037). LP-HA had 31% slower stair ascent time than HP-LA (p=0.033). There were no differences in chair rise performance between groups.

CONCLUSIONS

Knee extensor power asymmetry was unrelated to 400-m walk, stair ascent, and chair rise performance in older adults. Weak and strong limb powers were equally related to these functional measures, but a leftward shift of the power-mobility curve exists for the weak leg that may hinder clinical assessment if strength or power is measured on a single limb and symmetry is assumed. The greatest degree of knee extensor power asymmetry occurred at the fastest isokinetic velocity, which suggests high-speed muscle contractions may better differentiate laterality of function in older individuals.

A novel clinical evaluation method using maximum angular velocity during knee extension to assess lower extremity muscle function of older adults

The purpose of this study is to examine the utilities of maximum angular velocity (AV) assessment during knee extension (KE) using a gyroscope for clinical evaluation of exercise program for older adults. Two hundred and 4 community-dwelling older adults underwent a 3-month exercise intervention program. Outcome measures included AV during KE and other physical functions (isometric strength (IS), walking abilities, and balance functions). A correlation coefficient was used to evaluate the relationships between AV and other physical functions at baseline. The differences of physical functions before and after intervention were evaluated and the effect size of each measurement was calculated after the program. The AV measurement was significantly correlated with IS during KE (r=0.303, P<0.01) and other physical functions. Most correlation coefficients of angular velocity were greater than that of IS. All of physical assessments were significantly improved. Also, effect size of AV was greater than that of IS (d=0.45 vs. 0.42). AV of the lower extremities is useful to evaluate the effects of exercise intervention in the elderly.

Functional capacity assessment of upper limbs in healthy young adult subjects

Abstract Introduction Assessing the functional capacity of the upper limbs (UL) is essential to direct treatments in clinical practice but there is a lack of research on specific methods for this end. Objective To verify the relationship of physical activity, grip strength (GS) and body mass index (BMI) with performance on 6-minute Pegboard and Ring Test (6PBRT) in healthy subjects. Methods Cross-sectional, exploratory and quantitative study. Apparently healthy adults were evaluated, both sexes, according to sociodemographic and anthropometric aspects, health conditions, physical activity level (IPAQ - short version), GS and functional capacity of the upper limbs (6PBRT). The data were analyzed descriptively using means, standard deviations, absolute figures and percentages. Correlations were found between variables using Spearman’s correlation coefficient (p < 0.05). The Statistical Package for Social Sciences (SPSS) for Windows, version 17.0 was used for analysis purposes. Results In total, 50 individuals were evaluated, the majority classified as active (54%). The mean GS was 30.70 ± 9,47kgf and the average number of loops moved during the 6PBRT was 277.6 ± 34.48. There was no correlation between the number of rings moved in 6PBRT and the level of physical activity (r = 0.076; p = 0.602), GS (r = -0.008; p = 0.956) or BMI (r = 0.031; p = 0.829). Conclusion The level of physical activity, GS and BMI did not influence the performance on 6PBRT, demonstrated by the lack of correlation between these variables.

Dynapenia and Metabolic Health in Obese and Nonobese Adults Aged 70 Years and Older: The LIFE Study

OBJECTIVE

The purpose of this study was to examine the relationship between dynapenia and metabolic risk factors in obese and nonobese older adults.

METHODS

A total of 1453 men and women (age ≥70 years) from the Lifestyle Interventions and Independence for Elders (LIFE) Study were categorized as (1) nondynapenic/nonobese (NDYN-NO), (2) dynapenic/nonobese (DYN-NO), (3) nondynapenic/obese (NDYN-O), or (4) dynapenic/obese (DYN-O), based on muscle strength (Foundation for the National Institute of Health criteria) and body mass index. Dependent variables were blood lipids, fasting glucose, blood pressure, presence of at least 3 metabolic syndrome (MetS) criteria, and other chronic conditions.

RESULTS

A significantly higher likelihood of having abdominal obesity criteria in NDYN-NO compared with DYN-NO groups (55.6 vs 45.1%, P ≤ .01) was observed. Waist circumference also was significantly higher in obese groups (DYN-O = 114.0 ± 12.9 and NDYN-O = 111.2 ± 13.1) than in nonobese (NDYN-NO = 93.1 ± 10.7 and DYN-NO = 92.2 ± 11.2, P ≤ .01); and higher in NDYN-O compared with DYN-O (P = .008). Additionally, NDYN-O demonstrated higher diastolic blood pressure compared with DYN-O (70.9 ± 10.1 vs 67.7 ± 9.7, P ≤ .001). No significant differences were found across dynapenia and obesity status for all other metabolic components (P > .05). The odds of having MetS or its individual components were similar in obese and nonobese, combined or not with dynapenia (nonsignificant odds ratio [95% confidence interval]).

CONCLUSION

Nonobese dynapenic older adults had fewer metabolic disease risk factors than nonobese and nondynapenic older adults. Moreover, among obese older adults, dynapenia was associated with lower risk of meeting MetS criteria for waist circumference and diastolic blood pressure. Additionally, the presence of dynapenia did not increase cardiometabolic disease risk in either obese or nonobese older adults.

Handgrip strength, quadriceps muscle power, and optimal shortening velocity roles in maintaining functional abilities in older adults living in a long-term care home: a 1-year follow-up study

Purpose

To assess the relative role of handgrip strength (HGS), quadriceps muscle power (P_max), and optimal shortening velocity (υ_opt) in maintaining functional abilities (FAs) in older adults living in a long-term care home over a 1-year follow-up.

Subjects and methods

Forty-one inactive older institutionalized adults aged 69.8±9.0 years participated in this study. HGS, P_max, υ_opt, cognitive function using the Mini-Mental State Examination, depressive symptoms using the Geriatric Depression Scale, nutritional status using the Mini Nutritional Assessment (MNA), and physical activity (PA) using the Seven-Day Physical Activity Recall Questionnaire were assessed at baseline and at 1-year follow-up. FAs were assessed with activities of daily living (ADL), instrumental ADL, and Timed Up & Go test.

Results

Both at baseline and at follow-up, FAs were related to age, HGS, P_max/kg, υ_opt, MNA, and PA. These associations were generally similar in both sexes. As revealed in multiple regression analysis, υ_opt was the strongest predictor of FA, followed by P_max/kg, PA, and MNA. FA deteriorated after 1 year as measured by ADL and Timed Up & Go test. P_max and υ_opt, but not HGS, also decreased significantly after 1 year. Nevertheless, 1-year changes in FAs were not related to changes in HGS, P_max, υ_opt, or PA.

Conclusion

The 1-year period of physical inactivity among older institutionalized adults was found to have a negative effect on their FAs, P_max, and υ_opt. The present study demonstrates that P_max and, especially, υ_opt correlated with FAs of older adults more than HGS, both at baseline and at follow-up. Despite this, 1-year natural fluctuations of PA, P_max, and υ_opt are not significant enough to influence FAs in inactive institutionalized older adults.

Effects of Postprandial Blood Pressure on Gait Parameters in Older People

Postprandial hypotension (PPH), a fall in systolic blood pressure (SBP) within 2 h of a meal, may detrimentally affect gait parameters and increase the falls risk in older people. We aimed to determine the effects of postprandial SBP on heart rate (HR), gait speed, and stride length, double-support time and swing time variability in older subjects with and without PPH. Twenty-nine subjects were studied on three days: glucose (“G”), water and walk (“WW”), glucose and walk (“GW”). Subjects consumed a glucose drink on “G” and “GW” and water on “WW”. The “G” day determined which subjects had PPH. On “WW” and “GW” gait was analyzed. Sixteen subjects demonstrated PPH. In this group, there were significant changes in gait speed (p = 0.040) on “WW” and double-support time variability (p = 0.027) on “GW”. The area under the curve for the change in gait parameters from baseline was not significant on any study day. Among subjects without PPH, SBP increased on “WW” (p < 0.005) and all gait parameters remained unchanged on all study days. These findings suggest that by changing gait parameters, PPH may contribute to an increased falls risk in the older person with PPH.

Age-associated declines in muscle mass, strength, power, and physical performance: impact on fear of falling and quality of life

This 3-year longitudinal study among older adults showed that declining muscle mass, strength, power, and physical performance are independent contributing factors to increased fear of falling, while declines of muscle mass and physical performance contribute to deterioration of quality of life. Our findings reinforce the importance of preserving muscle health with advancing age.

INTRODUCTION

The age-associated loss of skeletal muscle quantity and function are critical determinants of independent physical functioning in later life. Longitudinal studies investigating how decrements in muscle components of sarcopenia impact fear of falling (FoF) and quality of life (QoL) in older adults are lacking.

METHODS

Twenty-six healthy older subjects (age, 74.1 ± 3.7; Short Physical Performance Battery (SPPB) score ≥10) and 22 mobility-limited older subjects (age, 77.2 ± 4.4; SPPB score ≤9) underwent evaluations of lower extremity muscle size and composition by computed tomography, strength and power, and physical performance at baseline and after 3-year follow-up. The Falls Efficacy Scale (FES) and Short Form-36 questionnaire (SF-36) were also administered at both timepoints to assess FoF and QoL, respectively.

RESULTS

At 3-year follow-up, muscle cross-sectional area (CSA) (p < 0.013) and power decreased (p < 0.001), while intermuscular fat infiltration increased (p < 0.001). These decrements were accompanied with a longer time to complete 400 m by 22 ± 46 s (p < 0.002). Using linear mixed-effects regression models, declines of muscle CSA, strength and power, and SPPB score were associated with increased FES score (p < 0.05 for each model). Reduced physical component summary score of SF-36 over follow-up was independently associated with decreased SPPB score (p < 0.020), muscle CSA (p < 0.046), and increased 400 m walk time (p < 0.003).

CONCLUSIONS

In older adults with and without mobility limitations, declining muscle mass, strength, power, and physical performance contribute independently to increase FoF, while declines of muscle mass and physical performance contribute to deterioration of QoL. These findings provide further rationale for developing interventions to improve aging muscle health.

Sex difference in age-related changes in knee extensor strength and power production during a 10-times-repeated sit-to-stand task in Japanese elderly

Background

For middle-aged and elderly women, age-related decline in an index representing power production during STS task (STS-PI), calculated by using an equation reported previously, has been shown to be greater than that in the force generation capability of lower extremity. Whether this is specific to women remains unclear. This study examined how the age-related changes in knee extensor strength and power production during STS differ between Japanese men and women aged 65 years or older.

Methods

The time taken for a 10-times-repeated STS test (STS time) and force developed during maximal voluntary isometric knee extension (KE-F) were determined in Japanese younger-old (262 men and 285 women) aged 65–74 years and older-old (96 men and 89 women) aged 75–90 years. STS-PI was calculated using the following equation: STS-PI = (body height − 0.4) × body mass × 10/STS time.

Results

KE-F and STS-PI were significantly greater in the younger-old than in the older-old group (p < 0.0001) and in men than in women (p < 0.0001). STS-PI and KE-F, expressed as the percentages of the mean value of the corresponding variable for the younger-old group (%STS-PI and %KE-F, respectively), were negatively correlated to chronological age in both men (r = −0.386 and r = −0.269, respectively, p < 0.0001) and women (r = −0.504 and r = −0.294, respectively, p < 0.0001). Regression slopes in the relationship between age and %KE-F were not significantly different between men (−1.521) and women (−1.618). However, regression slope in the relationship between age and %STS-PI was significantly steeper in women (−3.108) than in men (−2.170) (p < 0.05). In OOG, %KE-F had no significant effect of sex, but %STS-PI was significantly lower in women than in men (p < 0.001).

Conclusions

In Japanese men and women aged 65 years or over, age-related loss in power production during STS is steeper in women than in men, with greater magnitude than that in knee extensor strength. This suggests a higher priority of improving power generation capability during whole-body movement such as STS in older women than in older men.

Lung function and six-minute walk test performance in individuals with sickle cell disease

Background

Sickle Cell Disease (SCD), which is characterized by a mutation in the gene encoding beta hemoglobin, causes bodily dysfunctions such as impaired pulmonary function and reduced functional capacity.

Objective

To assess changes in pulmonary function and functional capacity in patients with SCD and to identify the relationships between these variables.

Method

We evaluated sociodemographic, anthropometric, lung function (spirometry), respiratory (manovacuometer), peripheral muscle strength (Handgrip strength - HS) and functional capacity (i.e., the six-minute walk test) parameters in 21 individuals with SCD (average age of 29±6 years). Shapiro-Wilk, paired Student's, Wilcoxon, Pearson and Spearman correlation tests were used for statistical analyses, and the significance threshold was set at p<0.05.

Results

A total of 47.6% of the study subjects exhibited an altered ventilation pattern, 42.8% had a restrictive ventilatory pattern (RVP) and 4.8% exhibited a mixed ventilatory pattern (MVP). The observed maximal inspiratory pressure (MIP) values were below the predicted values for women (64 cmH₂O), and the maximum expiratory pressure (MEP) values, HS values and distance walked during the 6MWT were below the predicted values for both men (103 cmH₂O, 39 Kgf and 447 m, respectively) and women (64 cmH₂O; 27 Kgf; 405 m, respectively). Positive correlations were observed between maximum voluntary ventilation (MVV) and MEP (r=0.4; p=0.046); MVV and BMI (r=0.6; p=0.003); and between HS and MIP (r=0.7; p=0.001), MEP (r=0.6; p=0.002), MVV (r=0.5; p=0.015), distance walked in the 6MWT (r=0.4; p=0.038) and BMI (r=0.6; p=0.004).

Conclusions

SCD promoted changes in lung function and functional capacity, including RVPs and a reduction in the distance walked in the 6MWT when compared to the predictions. In addition, significant correlations between the variables were observed.

Clinical strategies for addressing muscle weakness following knee injury

Muscle strength is a determinate of physical function and increasing muscle strength is an important clinical goal for patients with knee injury. This article discusses the emerging evidence regarding a novel rehabilitation strategy that uses disinhibitory modalities to increase neuromuscular activation in conjunction with traditional muscle strengthening for the purpose of maximizing strength gains following acute knee injury or surgery and in patients with knee osteoarthritis. The use of disinhibitory modalities and specific types of neuromuscular training for clinically maximizing strength are discussed.

High-speed circuit training vs hypertrophy training to improve physical function in sarcopenic obese adults: a randomized controlled trial

BACKGROUND

Progressive loss of muscle and strength with age is often coincident with increases in adiposity, leading to a condition called sarcopenic obesity. Studies have shown sarcopenic obese adults to be at higher risk for declines in physical function. Despite this rising public health concern, no intervention studies currently exist in this population.

METHODS

A total of 21 sarcopenic obese adults, 60 years or older, were randomized into two groups, strength/hypertrophy (SH, n=9) and high-speed circuit (HSC, n=8) and were trained for 15 weeks. The primary outcome was the SPPB modified as a measure of physical function, assessed by assessors blinded to randomization. Secondary outcomes were lower body and upper body power and strength, instrumental activities of daily living (IADL), ratings of perceived exertion (RPE), body fat % (BF%), skeletal muscle index (SMI), and grip strength (GRP).

RESULTS

For the SPPB results favored HSC over SH (1.1, 95% CI (-.1 to 2.4), p=.08) and showed a moderate effect size (Hedge g=0.6, 95% CI (-0.4, 1.6)). For secondary outcomes, lower body power (mean difference=158 W, 95% CI (2, 315); p=.01) and RPE (mean difference=-1.5, 95% CI (-2.9, -0.12); p=.04) also favored HSC. IADL, SMI, BF%, upper and lower body strength and upper body power, showed no statistically significant differences between groups.

CONCLUSIONS

Considering the moderate effect size, the large treatment effect shown by the upper limit of the 95% CI, the low perceived exertion, and no adverse effects, HSC training should be further investigated with a larger sample size in sarcopenic obese adults.