Lower extremity muscle quality and gait variability in older adults

Strength-balance supplemented with computerized cognitive training to improve dual task gait and divided attention in older adults: a multicenter randomized-controlled trial

BACKGROUND

Exercise interventions often do not combine physical and cognitive training. However, this combination is assumed to be more beneficial in improving walking and cognitive functioning compared to isolated cognitive or physical training.

METHODS

A multicenter parallel randomized controlled trial was conducted to compare a motor to a cognitive-motor exercise program. A total of 182 eligible residents of homes-for-the-aged (n = 159) or elderly living in the vicinity of the homes (n = 23) were randomly assigned to either strength-balance (SB) or strength-balance-cognitive (SBC) training. Both groups conducted similar strength-balance training during 12 weeks. SBC additionally absolved computerized cognitive training. Outcomes were dual task costs of walking, physical performance, simple reaction time, executive functions, divided attention, fear of falling and fall rate. Participants were analysed with an intention to treat approach.

RESULTS

The 182 participants (mean age ± SD: 81.5 ± 7.3 years) were allocated to either SB (n = 98) or SBC (n = 84). The attrition rate was 14.3%. Interaction effects were observed for dual task costs of step length (preferred walking speed: F(1,174) = 4.94, p = 0.028, η2 = 0.027, fast walking speed: F(1,166) = 6.14, p = 0.009, η2 = 0.040) and dual task costs of the standard deviation of step length (F(1,166) = 6.14, p = 0.014, η2 = 0.036), in favor of SBC. Significant interactions in favor of SBC revealed for in gait initiation (F(1,166) = 9.16, p = 0.003, η2 = 0.052), 'reaction time' (F(1,180) = 5.243, p = 0.023, η² = 0.028) & 'missed answers' (F(1,180) = 11.839, p = 0.001, η² = 0.062) as part of the test for divided attention. Within-group comparison revealed significant improvements in dual task costs of walking (preferred speed; velocity (p = 0.002), step time (p = 0.018), step length (p = 0.028), fast speed; velocity (p < 0.001), step time (p = 0.035), step length (p = 0.001)), simple reaction time (p < 0.001), executive functioning (Trail making test B; p < 0.001), divided attention (p < 0.001), fear of falling (p < 0.001), and fall rate (p < 0.001).

CONCLUSIONS

Combining strength-balance training with specific cognitive training has a positive additional effect on dual task costs of walking, gait initiation, and divided attention. The findings further confirm previous research showing that strength-balance training improves executive functions and reduces falls.

TRIAL REGISTRATION

This trial has been registered under ISRCTN75134517.

Effects of single vs. multiple-set short-term strength training in elderly women

The strength training has been shown to be effective for attenuating the age-related physiological decline. However, the adequate volume of strength training volume adequate to promote improvements, mainly during the initial period of training, still remains controversial. Thus, the purpose of this study was to compare the effects of a short-term strength training program with single or multiple sets in elderly women. Maximal dynamic (1-RM) and isometric strength, muscle activation, muscle thickness (MT), and muscle quality (MQ = 1-RM and MT quadriceps quotient) of the knee extensors were assessed. Subjects were randomly assigned into one of two groups: single set (SS; n = 14) that performed one set per exercise or multiple sets (MS; n = 13) that performed three-sets per exercise, twice weekly for 6 weeks. Following training, there were significant increases (p ≤ 0.05) in knee extension 1-RM (16.1 ± 12 % for SS group and 21.7 ± 7.7 % for MS group), in all MT (p ≤ 0.05; vastus lateralis, rectus femoris, vastus medialis, and vastus intermedius), and in MQ (p ≤ 0.05); 15.0 ± 12.2 % for SS group and 12.6 ± 7.2 % for MS group), with no differences between groups. These results suggest that during the initial stages of strength training, single- and multiple-set training demonstrate similar capacity for increasing dynamic strength, MT, and MQ of the knee extensors in elderly women.

Identifying recreational physical activities associated with muscle quality in men and women aged 50 years and over

BACKGROUND

Several studies conducted in a laboratory-related environment have shown that exercise is associated with increased muscle quality in older adults. The aim of the present study was to investigate whether recreational exercise may also be associated with muscle quality in men and women aged 50 years and over.

METHODS

Data are from 312 individuals (215 women) aged 50 years and older. Body composition (dual-energy X-ray absorptiometry) and knee extension strength (KES) of the right leg (one repetition maximum) were assessed. Muscle quality (MQ) (KES/right lower limb lean mass) was calculated. Recreational exercises (duration and weekly amount) were determined by structured interview.

RESULTS

The duration of the period during which participants practiced resistance activities was the only predictor of MQ (p = 0.018) and explained an additional 1.6 % of the variance in MQ, after controlling for age and gender. Furthermore, the weekly amount of practice of aerobic activities significantly interacted with age (p < 0.001) to determine MQ.

CONCLUSIONS

Findings suggest that long-term engagement in resistance exercise is beneficial for muscle quality and should be encouraged. Furthermore, beyond 60 years, aerobic activities also seem to be positively associated with muscle quality.

Echo intensity is negatively associated with functional capacity in older women

Muscle quality is an important component of the functional profile of the elderly, and previous studies have shown that both muscle quantity and quality independently contribute to muscle strength of the elderly. This study aimed to verify the association between quadriceps femoris muscle quality, analyzed by specific tension and echo intensity (EI), and rate of torque development (RTD) of the knee extensor muscles with the functional performance in elderly active women. Forty-five healthy, active elderly women (70.28 ± 6.2) volunteered to participate in this study. Quadriceps femoris muscle thickness and EI were determined by ultrasonography. Knee extension isometric peak torque and RTD were obtained from maximal isometric voluntary contraction curves. The 30-s sit-to-stand-up (30SS) test and usual gait speed (UGS) test were applied to evaluate functional performance. Rectus femoris EI presented a significant negative correlation with 30SS (r = -0.505, P < 0.01), UGS (r s = -0.347, P < 0.05), and isometric peak torque (r = -0.314, P < 0.05). The quadriceps femoris EI correlated negatively with 30SS (r = -0.493, P < 0.01) and isometric peak torque (r = -0.409, P < 0.01). The EI of the quadriceps femoris and all quadriceps muscle portions significantly correlated with RTD. RTD significantly correlated with physical performance in both functional tests (30SS = r = 0.340, P < 0.05; UGS = r s = 0.371, P < 0.05). We concluded that muscle EI may be an important predictor of functional performance and knee extensor power capacity in elderly, active women.

Tablet-based strength-balance training to motivate and improve adherence to exercise in independently living older people: part 2 of a phase II preclinical exploratory trial

BACKGROUND

Home-based exercise programs can improve physical functioning and health status of elderly people. Successful implementation of exercise interventions for older people presents major challenges and supporting elderly people properly while doing their home-based exercises is essential for training success. We developed a tablet-based system-ActiveLifestyle-that offers older adults a home-based strength-balance training program with incorporated motivation strategies and support features.

OBJECTIVE

The goal was to compare 3 different home-based training programs with respect to their effect on measures of gait quality and physical performance through planned comparisons between (1) tablet-based and brochure-based interventions, (2) individual and social motivation strategies, and (3) active and inactive participants.

METHODS

A total of 44 autonomous-living elderly people (mean 75, SD 6 years) were assigned to 3 training groups: social (tablet guided, n=14), individual (tablet guided, n=13), and brochure (brochure guided, n=17). All groups joined a 12-week progressive home-based strength-balance training program. Outcome measures were gait performance under single and dual task conditions, dual task costs of walking, falls efficacy, and physical performance as measured by the Short Physical Performance Battery (SPPB). Furthermore, active (≥75% program compliance) and inactive (<75% program compliance) individuals were compared based on their characteristics and outcome measures.

RESULTS

The tablet groups showed significant improvements in single and dual task walking, whereas there were no significant changes observable in the brochure group. Between-groups comparisons revealed significant differences for gait velocity (U=138.5; P=.03, r=.33) and cadence (U=138.5, P=.03 r=.34) during dual task walking at preferred speed in favor of the tablet groups. The brochure group had more inactive participants, but this did not reach statistical significance (U=167, P=.06, r=.29). The active participants outperformed the inactive participants in single and dual task walking, dual task costs of walking, and SPPB scores. Significant between-groups differences were seen between the tablet groups and the brochure group, in favor of the tablet groups.

CONCLUSIONS

A tablet-based strength-balance training program that allows monitoring and assisting autonomous-living older adults while training at home was more effective in improving gait and physical performance when compared to a brochure-based program. Social or individual motivation strategies were equally effective. The most prominent differences were observed between active and inactive participants. These findings suggest that in older adults a tablet-based intervention enhances training compliance; hence, it is an effective way to improve gait.

Home-based exercise program and fall-risk reduction in older adults with multiple sclerosis: phase 1 randomized controlled trial

OBJECTIVE

To determine the feasibility, safety, and efficacy of a home-based exercise intervention targeting fall risk in older adults with multiple sclerosis.

DESIGN

A randomized controlled pilot trial.

SETTING

A home-based exercise program.

INTERVENTION

Participants were randomly allocated to either a home-based exercise intervention group (n = 13) or a waiting list control group (n = 14). The exercise group completed exercises targeting lower muscle strength and balance three times a week for 12 weeks. The control group continued normal activity.

MEASURES

Fall risk (Physiological Profile Assessment scores), balance (Berg Balance Scale), and walking testing prior to and immediately following the 12-week intervention. Each outcome measure was placed in an analysis of covariance with group as the between-subject factor and baseline values as the covariate. Effect sizes were calculated.

RESULTS

Twelve participants from the control group and ten from the exercise group completed the study. There were no related adverse events. Fall risk was found to decrease in the exercise group following the intervention (1.1 SD 1.0 vs. 0.6 SD 0.6) while there was an increase in fall risk in the control group (1.9 SD 1.5 vs. 2.2 SD 1.9). Effect sizes for most outcomes were large (η(2) > 0.15).

CONCLUSIONS

Home-based exercise was found to be feasible, safe, and effective for reducing physiological fall risk in older adults with multiple sclerosis. Our findings support the implementation of a larger trial to reduce fall risk in persons with multiple sclerosis.

Exploring the role of muscle mass, obesity, and age in the relationship between muscle quality and physical function

BACKGROUND

Divergent conclusions emerge from the literature regarding the relationship between muscle quality (defined as muscle strength per unit of muscle mass) and physical function. These contrasted results may be due to the influence of factors such as age, obesity, and muscle mass itself. Consequently, the aim of the present study was to explore the role of these factors in the relationship between muscle quality (MQ) and physical function.

METHODS

Data are from 312 individuals (97 men and 215 women) aged 50 years and older. Body composition (dual energy X-ray absorptiometry) and knee extension strength of the right leg (1 repetition maximum) were assessed. Appendicular lean body mass index (AppLBMI) and MQ (knee extension strength /right leg lean mass) were calculated. A composite score of physical function was created based on the timed up-and-go, alternate step, sit-to-stand, and balance tests.

RESULTS

MQ was significantly associated with physical function when AppLBMI (β = 0.179; P = .004) and body mass index (BMI) (β = 0.178; P = .003), but not age (β = 0.065; P = .26), were included in regression analysis. AppLBMI (β = 0.221; P < .001), BMI (β = 0.234; P < .001), and age (β = 0.134; P = .018) significantly interacted with MQ to determine physical function.

CONCLUSIONS

Our results show that muscle mass, obesity, and age influence the relationship between MQ and physical function, suggesting that these factors should be taken into account when interpreting MQ. Even so, higher levels of MQ were associated with higher physical function scores. Nutritional and physical activity interventions may be designed in this regard.

Muscle Quality in Older Adults

The population of older adults in the United States is steadily growing and identifying factors that contribute to healthy aging is a public health priority. Changes in body composition are a hallmark of the aging process and have been implicated in the loss of physical function among older adults. In particular, age-related declines in muscle strength and power occur at a faster rate than the loss of muscle mass (sarcopenia), and this suggests a decrease in muscle quality of older adults. Muscle quality has traditionally been defined as muscle function (strength or power) per unit of muscle size (mass or cross-sectional area) and a growing body of literature suggests that lower body muscle quality may be critical for maintaining functional independence with age. However, the literature regarding the definition of muscle quality and its relationship with health outcomes in older adults has not been adequately reviewed. Thus, the aim of this report is to highlight the contemporary literature regarding age-related changes in muscle quality and its relationship with health outcomes in community-dwelling older adults.

Gait variability and disability in multiple sclerosis

Gait variability is clinically relevant in some populations, but there is limited documentation of gait variability in persons with multiple sclerosis (MS). This investigation examined average and variability of spatiotemporal gait parameters in persons with MS and healthy controls and subsequent associations with disability status. 88 individuals with MS (age 52.4±11.1) and 20 healthy controls (age 50.9±8.7) performed two self-paced walking trials on a 7.9-m electronic walkway to determine gait parameters. Disability was indexed by the Expanded Disability Status Scale (EDSS) and ranged between 2.5 and 6.5. Gait variability was indexed by standard deviation (SD) and coefficient of variation (CV=SD/mean) of step time, step length, and step width. Average gait parameters were significantly correlated with EDSS (ρ=0.756-0.609) and were significantly different in individuals with MS compared to controls (p≤0.002). Also, step length (p<0.001) and step time (p<0.001) variability were both significantly greater in MS compared to controls. EDSS was positively correlated with step length variability and individuals with MS who used assistive devices to walk had significantly greater step length variability than those who walked independently (p's<.05). EDSS was correlated with step time and length variability even when age was taken into account. Additionally, Fisher's z test of partial correlations revealed that average gait parameters were more closely related to disability status than gait variability in individuals with MS. This suggests that focusing on average gait parameters may be more important than variability in therapeutic interventions in MS.

Gait variability and multiple sclerosis

Gait variability, that is, fluctuations in movement during walking, is an indicator of walking function and has been associated with various adverse outcomes such as falls. In this paper, current research concerning gait variability in persons with multiple sclerosis (MS) is discussed. It is well established that persons with MS have greater gait variability compared to age and gender matched controls without MS. The reasons for the increase in gait variability are not completely understood. Evidence indicates that disability level, assistive device use, attentional requirement, and fatigue are related to gait variability in persons with MS. Future research should address the time-evolving structure (i.e., temporal characteristics) of gait variability, the clinical importance of gait variability, and underlying mechanisms that drive gait variability in individuals with MS.

Footfall placement variability and falls in multiple sclerosis

Gait variability (i.e., fluctuations in walking) provides unique information about the control of movement and is associated with falls. This investigation examined the association between gait variability and falls in persons with multiple sclerosis (MS) and healthy controls. Traditional distributional metrics of gait variability (i.e., coefficient of variation (CV)) and a novel metric based on Fourier series analysis of footfall placement variability were determined for 41 individuals with MS and 20 age- and sex-matched controls. Spatiotemporal parameters of gait were collected using a 7.9 m electronic walkway that recorded individual footfalls during steady state comfortable walking. Persons with MS were divided into two groups based on fall history (non-fallers and recurrent fallers). Overall, persons with MS had greater gait variability than controls as indexed by CV and Fourier-based variability (p's < 0.05). Moreover, recurrent fallers with MS had greater Fourier-based variability than non-fallers with MS (p = 0.025), whereas there was no difference in MS groups in traditional gait variability metrics (p > 0.05). These observations highlight that footfall placement variability is related to fall status in MS. Future work determining the sensitivity of footfall placement variability to dysfunction is warranted.