Height of Chair Seat and Movement Characteristics in Sit-to-Stand by Young and Elderly Adults

Comparison of low-dose maximal-intent versus controlled-tempo resistance training on quality-of-life, functional capacity, and strength in untrained healthy adults: a comparative effectiveness study

Lack of physical activity is a global issue for adults that can lead to sedentary behaviour and a higher prevalence of health complications and chronic diseases, resulting in reduced quality-of-life (QoL) and functional capacity (FC). A potential strategy to mitigate this inactivity is low-dose resistance training (RT); however, physiological, and psychological responses are limited in evidence. Twenty untrained participants aged 30-60 years old (mean ± SD age 42 ± 7 years, mass 77 ± 13 kg, stature 166 ± 8 cm; 18 females and two males) were recruited and randomly assigned to maximal velocity-intent (MI, n = 10) or controlled-tempo (CT, n = 10) RT according to CONsolidated Standards of Reporting Trials (CONSORT) guidelines. Participants attended one training session per week for 6 weeks, consisting of five sets of five repetitions at 60% of one-repetition maximum (1RM) leg press. The interventions differed only during the concentric phase, with MI group pushing with maximal intent, and CT group pushing in a time-controlled manner (3 s). Outcome measures assessed pre- and post-RT included body mass, body mass index (BMI), strength-to-mass ratio, bipedal balance, 6-minute walk test (6MWT), 30-second sit-to-stand (30s-STS), timed up and go (TUG), and leg press 1RM. Time effects were observed for all demographics and FC-related outcomes, such as identical reductions in mass and BMI (- 2%), improvements in strength-to-mass ratio (25%) leg press 1RM (22%), 6MWT (3%), and 30s-STS (14%), as well as a 9% improvement in both TUG-clockwise and anticlockwise. Results show low-dose once-weekly RT is effective in improving QoL, FC, and strength in untrained healthy adults, regardless of modality. Positive responses from participants suggest an increased likelihood of consistent participation for low-dose once-weekly RT over more intense modalities. Retrospective ClinicalTrials.gov ID (TRN): NCT06107855, 24/10/2023.

The impact of seat height on 1-min sit-to-stand test performance in COPD: a randomised crossover trial

Study question

Is there a difference in the number of repetitions in the 1-minute sit-to-stand (1MSTS) test using an individually adapted seat height to 90° knee flexion (1MSTS_IND), compared with the commonly used standard chair seat height of 46 cm (1MSTS_STD), in people with COPD?

Methods

We conducted a single-centre, single-blinded, randomised crossover trial in people with COPD between August 2020 and March 2021 at a specialised rehabilitation clinic in Switzerland. After a learning 1MSTS test, all participants performed two 1MSTS tests in random order on consecutive days. Participants were blinded, as they did not receive detailed information on the testing protocols.

Results

49 individuals with COPD (47% female) participated. In a regression model adjusted for sequence period and subject, 1MSTS test performance was lower on 1MSTS_IND compared to 1MSTS_STD (−0.78 repetitions, 95% CI −1.47 to −0.11). In a second regression model additionally including the knee angle and an interaction term (1MSTS_IND×knee angle), the interaction term was significant: 0.18 (95% CI 0.05 to 0.30). The limits of agreement were between −5.5 and 4 repetitions.

Conclusion

Although we observed a statistically significant difference between 1MSTS_IND and 1MSTS_STD on a population level, the difference is negligible. Further studies may be needed to determine whether individual adaptation of seat height is needed for very tall or short people to ensure a valid assessment of 1MSTS test performance in COPD.

Performing the 1MSTS test on an individually adjusted chair versus a standard chair results in fewer repetitions (mean difference −0.78, 95% CI −1.47 to −0.11). However, the difference in repetitions is clinically negligible.https://bit.ly/3Oc8Rvp

The Effects of Displacing Sedentary Behavior With Two Distinct Patterns of Light Activity on Health Outcomes in Older Adults (Implications for COVID-19 Quarantine)

Rationale: The COVID-19 pandemic is limiting outdoor and community-based activities, especially for older adults owing to the requirement for self-isolation, potentially increasing prolonged sedentary behavior (SB). Given a poor tolerance for intense exercise, SB displacement with light intensity physical activity (LIPA) is a promising health enhancing alternative. Therefore, the aims of this study were to investigate the effects of two different types of SB displacement on health outcomes in older adults and any differential impact of associated LIPA pattern.

Method: 28 older women (age: 73 ± 5 years, height: 1.60 ± 0.07 m, weight: 67 ± 10 kg, and BMI: 26.1 ± 3.6 kg/m²) underwent overnight fasted dual energy x-ray absorptiometry (DEXA) imaging, blood sampling, and functional assessments before being randomly allocated to one of two groups: (1) single continuous bout of 45–50 min LIPA daily (n = 14); or (2) SB fragmentation (SBF; ~48 min LIPA daily, 2 min LIPA for every 30 min of SB; n = 14). Compliance was systematically monitored using tri-axial accelerometery. All measures were taken at weeks 0 and 8.

Results: Physical behavior significantly altered (decreased SB/increased LIPA; p < 0.05) and to a similar extent in both groups. We observed a significant reduction in serum triglycerides [p = 0.045, effect size (ɳ_p²) = 0.15; SBF: −0.26 ± 0.77 mmol/L, LIPA: −0.26 ± 0.51 mmol/L], improved 30 s sit-to-stand (STS) count (p = 0.002, ɳ_p² = 0.32, 2 ± 3 STS) and speed (p = 0.009, ɳ_p² = 0.35, −10 ± 33%), as well as increased average handgrip strength (p = 0.001, ɳ_p² = 0.45, 6 ± 12%), and gait speed (p = 0.005, ɳ_p² = 0.27, 0.09 ± 0.16 m/s) in both groups. Interestingly, SBF caused a greater increase in peak handgrip strength (8 ± 14%), compared to LIPA (2 ± 10%; p = 0.04, ɳ_p² = 0.38).

Conclusion: SB displacement induced significant improvements in fasting triglycerides, gait speed, as-well as STS endurance/speed in older women. Frequent vs. continuous SB displacement also caused greater increases in handgrip strength. While both SB displacement protocols display promise as efficacious home-based interventions for self-isolating older adults, our results would suggest a physical functioning advantage of the SBF protocol for certain outcomes.

Minimizing sedentary behavior (without increasing medium-to-vigorous exercise) associated functional improvement in older women is somewhat dependent on a measurable increase in muscle size

The optimal pattern of sedentarism displacement and mechanisms underlying its health effects are poorly understood. Therefore, the aim of this study was to quantify muscle-tendon adaptation in response to two different sedentarism displacement interventions and relate any adaptations to functional outcomes. Thirty-four older women (73±5yrs) underwent skeletal muscle-tendon size and functional assessments. Participants were randomly allocated to: Sedentary behavior fragmentation (SBF), Light intensity physical activity (LIPA), or Control groups. Measures were taken at weeks 0 and 8. Gait speed significantly increased (p=0.003), in both experimental groups (SBF: 0.06 ± 0.08m/s, 6±10%, LIPA: 0.06 ± 0.07m/s, 6±6%), but not control (-0.02 ± 0.12m/s, -2±9%). Accordingly, the relative change in Vastus Lateralis muscle volume, accounted for 30% (p=0.027), and 45% (p=0.0006) of the explained variance in the relative change in gait speed, for SBF and LIPA respectively. Gastrocnemius Medialis fascicle length changes were positively associated with gait speed changes, following LIPA exclusively (R²= 0.50, p=0.009). This is the first study to show SBF and LIPA are adequate loading in older women, with related muscle adaptation and clinically relevant gait speed improvements. Such adaptations appear similar irrespective of whether sedentarism displacement is prescribed in a single bout (LIPA) or in frequent micro-bouts (SBF).

BIOMECHANICAL COMPARISON OF MUSCLE USE PATTERNS OF YOUNG ADULTS AND OLDER ADULTS IN FLOOR AND BED TRANSFER MOVEMENTS

In this study, lift chair was developed to reduce safety accidents in the daily lives of elderly people with reduced muscle strength as the importance of health and well-being of the elderly was emphasized by the increase in the elderly population. In addition, muscle strength characteristics of the elderly and those in their 20s were compared and analyzed when using lift chair. The lift chair used are chairs that can be raised and lowered and designed to reach the floor in full descent. The EMG was measured to compare the near-term use of lift chair to those in their 20s. As a result, the elderly had higher use of lower limb muscles compared to young participants. It was judged that the upper and lower extremities were difficult to move due to the characteristics of the elderly with reduced muscle strength, and that the upper and lower limbs were used simultaneously to complete the movement. The results showed the characteristics of everyday motion of the elderly for the development of lift chair and can help improve design, function, etc. in later development of lift chair.

Sit-to-Stand Kinetics and Correlates of Performance in Young and Older Males

PURPOSE

To compare sit-to-stand (STS) kinetics in young (YM) and older (OM) males and determine correlates of STS performance.

METHODS

YM (n = 15, age = 20.7 ± 2.2 yrs) and OM (n = 15, age = 71.6 ± 3.9 yrs) performed a single STS task as quickly as possible on a force plate and the vertical ground reaction force (VGRF) signal was analyzed. Peak VGRF, as well as peak (100 ms rolling average), early (minimum VGRF to 50% peak VGRF), late (50% peak VGRF to peak VGRF), and overall (minimum VGRF to peak VGRF) rate of force development (RFD) were calculated. Power (absolute and relative) and velocity parameters as well as rate of electromyography rise (RER) were also obtained.

RESULTS

STS time, average power, early RFD, and lower limb lean mass were similar between groups (p > 0.05). All other power, velocity, RFD, and RER measures were lower in OM (p < 0.05; d = 0.41-2.19). Peak VGRF and all RFD measures, except late RFD, were strongly correlated with STS performance in OM, while peak VGRF and peak RFD were only moderately correlated with performance in YM.

CONCLUSIONS

Most kinetic variables, except absolute average power, were diminished in OM, and there was a preferential decrease in late RFD compared to early RFD. Peak VGRF and RFD exhibited stronger correlations with STS time and power in OM compared to YM, and early RFD appears to be more influential for STS performance than late RFD. These findings may be useful for practitioners/clinicians involved in designing interventions aimed at optimizing STS performance in older adults.

Effects of shelf bar assistance on kinetic control during sit-to-stand in healthy young and elderly subjects

This study aimed to determine the kinetic effects of using unilateral shelf bar, vertical grab bar (GB), and horizontal GB during sit-to-stand (STS) in young and elderly subjects. Twenty young adults aged 20-40 years and eighteen healthy elderly people aged ≥ 65 years old were recruited. The subjects performed STS with and without using the three types of bars. Bar reaction force (BRF) and maximum power (MP) defined as the maximal product calculated by multiplying the GRF and the velocity of the center of mass in each direction were measured using three-dimensional motion analysis, two load sensors of GB, and four force plates. The use of the shelf bar generated a significantly larger BRF in the vertical direction than the other bars (p < 0.05) and lower MP in the vertical direction than the horizontal bar (p < 0.05) and no bar (p < 0.05). In the younger subjects, only the use of the vertical bar generated a significantly larger BRF (p < 0.05) and negative MP (p < 0.05) in the forward direction than those in elderly subjects. The use of the shelf bar may assist the decreased MP in the vertical direction during STS in elderly people, resulting in decrease of failed STS in daily living. In contrast, the use of the vertical bar in the elderly may not generate sufficient BRF in the forward direction because of lack of eccentric control in the whole body in the forward direction during STS.

Classification of standing and sitting phases based on in-socket piezoelectric sensors in a transfemoral amputee

A transfemoral prosthesis is required to assist amputees to perform the activity of daily living (ADL). The passive prosthesis has some drawbacks such as utilization of high metabolic energy. In contrast, the active prosthesis consumes less metabolic energy and offers better performance. However, the recent active prosthesis uses surface electromyography as its sensory system which has weak signals with microvolt-level intensity and requires a lot of computation to extract features. This paper focuses on recognizing different phases of sitting and standing of a transfemoral amputee using in-socket piezoelectric-based sensors. 15 piezoelectric film sensors were embedded in the inner socket wall adjacent to the most active regions of the agonist and antagonist knee extensor and flexor muscles, i. e. region with the highest level of muscle contractions of the quadriceps and hamstring. A male transfemoral amputee wore the instrumented socket and was instructed to perform several sitting and standing phases using an armless chair. Data was collected from the 15 embedded sensors and went through signal conditioning circuits. The overlapping analysis window technique was used to segment the data using different window lengths. Fifteen time-domain and frequency-domain features were extracted and new feature sets were obtained based on the feature performance. Eight of the common pattern recognition multiclass classifiers were evaluated and compared. Regression analysis was used to investigate the impact of the number of features and the window lengths on the classifiers’ accuracies, and Analysis of Variance (ANOVA) was used to test significant differences in the classifiers’ performances. The classification accuracy was calculated using k-fold cross-validation method, and 20% of the data set was held out for testing the optimal classifier. The results showed that the feature set (FS-5) consisting of the root mean square (RMS) and the number of peaks (NP) achieved the highest classification accuracy in five classifiers. Support vector machine (SVM) with cubic kernel proved to be the optimal classifier, and it achieved a classification accuracy of 98.33 % using the test data set. Obtaining high classification accuracy using only two time-domain features would significantly reduce the processing time of controlling a prosthesis and eliminate substantial delay. The proposed in-socket sensors used to detect sit-to-stand and stand-to-sit movements could be further integrated with an active knee joint actuation system to produce powered assistance during energy-demanding activities such as sit-to-stand and stair climbing. In future, the system could also be used to accurately predict the intended movement based on their residual limb’s muscle and mechanical behaviour as detected by the in-socket sensory system.

Asymmetry in children with unilateral cerebral palsy during sit-to-stand movement: Cross-sectional, repeated-measures and comparative study

BACKGROUND

We aimed to compare motor strategies adopted by children with unilateral Cerebral Palsy and typically developing children during the performance of sit-to-stand.

METHODS

Eleven children with unilateral cerebral palsy and 20 typically developing children were evaluated. Kinematic and kinetic analysis of the sit-to-stand movement was performed. Three seat heights were evaluated: neutral (90° of hip-knee-ankle flexion), elevated to 120% of the neutral height, and lowered to 80% of the neutral height. As outcome variables, we considered sit-to-stand duration (temporal); initial, final and maximal sagittal angles and range of motion of trunk, pelvis, hip, knee, and ankle (kinematics); the peak of vertical ground reaction force (kinetics), and asymmetric index. Effect size is represented by η₂p.

FINDINGS

We found that for the lowered seat, all groups presented increased flexion of lower limbs and trunk to initiate sit-to-stand (p≤0.012; η₂p = 0.41-0.84), increased peak flexion of trunk, hip and knee (p≤0.01; η₂p = 0.39-0.88), increased range of motion of knee and trunk (p≤0.01; η₂p = 0.45-0.85) and the duration of sit-to-stand (p≤0.05 η₂p = 0.23-0.56). Children with unilateral cerebral palsy presented increased posterior pelvic tilt (p≤0.01) and decreased hip flexion of both lower limbs (p≤0.01) for all seat heights and moved their non-affected limb backward in the lowered seat (p≤0.01). Asymmetry was observed for the final and the maximal angles of the ankle in neutral and lowered seats in unilateral cerebral palsy (asymmetry index = 3.3-5.8%).

INTERPRETATION

The lowered seat height led to adaptive motor strategies in children with unilateral cerebral palsy, which should be considered in clinical practice.

Effects of bilateral swing-away grab bars on the biomechanics of stand-to-sit and sit-to-stand toilet transfers

PURPOSE

Kinetic characteristics of transfers to and from a toilet performed using bilateral grab bars are not fully quantified to inform grab bar design and configuration. The purpose of this study was to (1) determine effects of bilateral swing-away grab bars on peaks of ankle, knee and hip joint moments during grab bar assisted stand-to-sit and sit-to-stand transfers; and (2) determine effects of three different heights and widths of swing-away grab bars on the same kinetic characteristics.

METHODS

Healthy subjects (N = 11, age 25-58 years) performed stand-to-sit and sit-to-stand transfers with and without grab bars. In transfers with grab bars, 9 grab bar configurations were tested by varying their height from the floor (0.787 m, 0.813 m, 0.838 m; 31″-33″) and width, the distance of each grab bar from the toilet's centerline (0.330 m, 0.356 m, 0.381 m; 13″-15″). Motion capture, force plate and inverse dynamics analysis were used to determine lower limb joint moments.

RESULTS

The use of bilateral grab bars generally reduced the peak magnitude of extension moments at lower limb joints during stand-to-sit and sit-to-stand transfers (p < .05), except the ankle joint moments during stand-to-sit transfers. Relatively few differences in peak joint moments were found between studied grab bar widths or heights.

CONCLUSION

The obtained results suggest that the studied ranges of grab bar configurations reduce moment demands on the leg joints and thus decrease difficulty and required lower limb muscle effort to perform the transfers. Implications for Rehabilitation Maximizing the benefits of assistive technology in the built environment requires a careful assessment of their spatial and configurational dimensions, especially in respect to the needs and abilities of the intended users. Examining the kinetic characteristics of transfers to and from a toilet using the swing-away grab bars is useful for informing grab bar design and configuration recommendations for assisted living and skilled nursing facilities. Our findings suggest that the swing-away grab bars located at certain ranges are a reasonable alternative to the grab bars mandated by the current Americans with Disabilities Act (ADA) Accessibility Guidelines. Future research investigating the effects of grab bars on transfer performance should consider additional factors, such as a wider range of abilities and transfer methods of the users.

The influence of chair seat height on the performance of community-dwelling older adults' 30-second chair stand test

BACKGROUND AND AIMS

Although chair seat height affects the performance of sit-to-stand movement, no previous study has examined the influence of chair seat height on the 30-second chair stand test (CST).

METHODS

Fifty-five community-dwelling older adults (age 70.0 ± 6.3 years) performed the test from the standard height of 43 cm and then from five randomly ordered seat heights from 80 to 120 % of each participant's lower leg length.

RESULTS

Chair seat height significantly influences the performance of community-dwelling older adults' 30-s CST (F = 57.50, p < 0.001). The mean score for standard conditions was significantly lower from those at 120, 110, and 100 % conditions (p < 0.05). No significant difference was observed between the standard and 80 % conditions (p > 0.95) and between the standard and 90 % conditions (p = 0.353). When comparing the scores between the randomly ordered chair seat heights, all comparisons were significantly different (p < 0.001) except for the difference between the 120 and 110 % conditions (p = 0.104).

CONCLUSION

Chair seat height's relation to the lower leg length should be considered when interpreting 30-s CST scores. Additionally, it is necessary to optimize the chair seat height when using the 30-s CST as an outcome measure for exercise intervention or to screen for people with weaker lower extremities.

Describing Force Patterns: A Method for Classifying Sit-To-Stand Movement in Elderly People

The main contribution of this study is that it examined the sit-to-stand movements of elderly people and then established an assessment method to supplement the existing Berg Balance Scale for the risk of falling in elderly individuals. 36 elderly adults ( M age = 69.9 yr., SD = 4.0) volunteered to participate in this study. Three key points of the sit-to-stand movement were confirmed as aspects of the ground reaction force: the onset, maximum ground reaction force, and seat-off. Based on the characteristics indicated by the force data, the sit-to-stand movement sequences of those who were evaluated at low fall risk with a Berg Balance Scale score between 41 and 55 were classified into three patterns: typical-modal, multimodal, and incompetent-modal patterns. With this increased accuracy, medical practitioners can determine more clearly those participants who require further immediate medical consultation and those that are not at risk of falling.

Evaluation of key points in the sit-to-stand movement using two force platforms

Three key points of the sit-to-stand (STS) movement were confirmed as aspects of the ground reaction force (GRF): the onset, maximum GRF, and seat-off. 46 healthy subjects (M age = 22.2 yr., SD = 4.4) participated. During the STS movement, two vertical force platforms were used to measure the resultant GRF, defined as the whole-body force, and its two components, the buttock and leg GRFs. The onsets of the component GRFs identified the sequence of the important time points in the STS movement more precisely than the onset of the resultant GRF. Data showed that the maximum whole-body GRF, the maximum GRF of both legs, and seat-off appeared in sequence and not simultaneously.

Biomechanical analysis of gait and sit-to-stand patterns using a specially made knee supporter in healthy young and elderly individuals

This study examined the ergonomic effects of a specially made knee supporter containing spiral bone springs aimed at reducing physical stress on the leg muscles during sit-to-stand (STS) and walking. Twelve young females and fifteen elderly subjects performed STS and treadmill walking with and without a specially made supporter, which may be a simple device for aiding STS and/or walking. During STS, electromyography (EMG) was observed from the vastus lateralis of the right leg. The root mean square (RMS) and mean power frequency (MPF) were calculated from the observed EMG. The changing rate of maximal leg acceleration, the third time derivative of the leg position, was also assessed during treadmill walking at a freely chosen stride frequency and speed. A significant decrease in the RMS was observed during STS when wearing the supporter in both groups. A significant increase in the changing rate of maximal leg acceleration was found during walking with the supporter in both groups. MPF significantly increased when wearing the supporter only in the young group. These results showed that the supporter with spiral bone springs reduced physical stress placed on the quadriceps muscles during STS and walking. This ergonomic contrivance will reduce the possible "risk" of stumbling and/or falling in elderly individuals. The reduced physical burden on the quadriceps muscles will also reduce or delay muscle fatigue, which will further result in an increase in the amount of daily physical activities exhibited in physically poor populations.

Strategies for Posture Transfer Adopted by Elders during Sit-To-Stand and Stand-To-Sit

This study investigated whether three posture-transfer strategies, No support, Chair-arm, and Cane, were associated with the smallest hip-compressed angle and the smallest ankle-compressed angle during sit-to-stand and stand-to-sit for 12 elders ( M age = 81.3 yr., SD = 5.9) who volunteered to participate. Using an optoelectronic movement analyzer, the smallest compressed angles of the hip and ankle were measured during standing up and sitting down. The adopted strategies had significant effects on the smallest hip-compressed angle, but not the smallest ankle-compressed angle. Although cane use led to a larger trunk angular displacement than did chair-arm use, a cane can provide help during the whole transfer process. These two strategies may be seen as adaptive mechanisms to decrease risk of anterior disequilibrium.