Determination of reliable force platform parameters and number of trial to evaluate sit-to-stand movement

Unilateral transtibial prosthesis users load their intact limb more than their prosthetic limb during sit-to-stand, squatting, and lifting

BACKGROUND

Lower limb prosthesis users exhibit high rates of joint pain and disease, such as osteoarthritis, in their intact limb. Overloading of their intact limb during daily activities may be a contributing factor. Limb loading biomechanics have been extensively studied during walking, but fewer investigations into limb loading during other functional movements exist. The purpose of this study was to characterize the lower limb loading of transtibial prosthesis users during three common daily tasks: sit-to-stand, squatting, and lifting.

METHODS

Eight unilateral transtibial prosthesis users performed sit-to-stand (from three chair heights), squatting, and lifting a 10 kg box. Peak vertical ground reaction forces and peak knee flexion moments were computed for each limb (intact and prosthetic) to characterize limb loading and asymmetry. Ranges of motion of the intact and prosthetic ankles were also quantified.

FINDINGS

Users had greater peak ground reaction forces and knee flexion moments in their intact limb for all tasks (p < 0.02). On average, the intact limb had 36-48% greater peak ground reaction forces and 168-343% greater peak knee flexion moments compared to the prosthetic limb. The prosthetic ankle provided <10° of ankle range of motion for all tasks, less than half the range of motion provided by the intact ankle.

INTERPRETATION

Prosthesis users overloaded their intact limb during all tasks. This asymmetric loading may lead to an accumulation of damage to the intact limb joints, such as the knee, and may contribute to the development of osteoarthritis. Prosthetic design and rehabilitation interventions that promote more symmetric loading should be investigated for these tasks.

Optimal procedure and characteristics in using five times sit to stand test among older adults: A systematic review

BACKGROUND

Falls are a major concern for people of all ages, especially older adults with declining physical functions and deteriorating muscle strength. The Five Times Sit to Stand Test is used for the assessment of lower limb strength along with balance and postural control. Therefore, the systematic review at hand aimed to determine the optimal procedure and characteristics among older adults.

METHODS

The following databases served as the primary sources through which the target studies were searched for and obtained for review. They included Google Scholar, Pedro, BIOMED Central, Cochrane Library, MEDLINE, PUBMED and Science DIRECT. With the aim of fulfilling the eligibility criteria, 16 full-text studies were included and the quality assessment was performed. using the Thomas Tool.

RESULTS

The total number of the subjects who participated in the included studies was 15,130 and the ages of the aforementioned participants ranged from 60 to 80 years. In 15 of the studies, a stopwatch was used as the scoring method where the mean chair height of 42 cm was reported. Two studies reported that no significant influence of the arm position (P = .096) on the time allocated for test completion was identified. However, posterior foot placement (P < .001) led to shorter times of completion. Individuals who are unable to complete the test are more susceptible to activities of daily living related disabilities (P < .01) when compared to fall risk (P = .09).

CONCLUSION

The Five Times Sit-to-Stand Test is a safe test, providing added value to apply risk for falls in people at moderate risk and in healthy populations using standardized chair heights and stopwatches.

Temporal, Kinematic and Kinetic Variables Derived from a Wearable 3D Inertial Sensor to Estimate Muscle Power during the 5 Sit to Stand Test in Older Individuals: A Validation Study

The 5-Sit-to-stand test (5STS) is widely used to estimate lower limb muscle power (MP). An Inertial Measurement Unit (IMU) could be used to obtain objective, accurate and automatic measures of lower limb MP. In 62 older adults (30 F, 66 ± 6 years) we compared (paired t-test, Pearson's correlation coefficient, and Bland-Altman analysis) IMU-based estimates of total trial time (totT), mean concentric time (McT), velocity (McV), force (McF), and MP against laboratory equipment (Lab). While significantly different, Lab vs. IMU measures of totT (8.97 ± 2.44 vs. 8.86 ± 2.45 s, p = 0.003), McV (0.35 ± 0.09 vs. 0.27 ± 0.10 m∙s^-1, p < 0.001), McF (673.13 ± 146.43 vs. 653.41 ± 144.58 N, p < 0.001) and MP (233.00 ± 70.83 vs. 174.84 ± 71.16 W, p < 0.001) had a very large to extremely large correlation (r = 0.99, r = 0.93, and r = 0.97 r = 0.76 and r = 0.79, respectively, for totT, McT, McF, McV and MP). Bland-Altman analysis showed a small, significant bias and good precision for all the variables, but McT. A sensor-based 5STS evaluation appears to be a promising objective and digitalized measure of MP. This approach could offer a practical alternative to the gold standard methods used to measure MP.

The effects of standardised versus individualised seat height on 1-minute sit-to-stand test performance in healthy individuals: a randomised crossover trial

PURPOSE

We aimed to (i) investigate differences in 1-minute sit-to-stand test (1MSTST) performance (i.e., the number of repetitions) between a standardised modality (i.e., starting from a conventional chair with 46 cm seat height) and an individualised modality (i.e., starting with a knee joint flexion angle of 90°), and to (ii) quantify the influence of tibia and femur length on 1MSTST performance.

METHODS

Healthy participants were recruited for this randomised crossover study, performing each 1MSTST modality twice in a randomised order. The primary outcome was the number of repetitions in the 1MSTST. Secondary endpoints were the acute responses in peripheral oxygen saturation, heart rate, and leg fatigue and dyspnoea. Additionally, we investigated correlations of performance with knee extensor strength in both modalities.

RESULTS

Thirty participants were recruited and completed the study. They achieved significantly less repetitions in the standardised 1MSTST compared to the individualised 1MSTST (B = - 12.1, 95% confidence interval [95% CI] =  - 14.8/- 9.4, p < 0.001). We found a significant effect of femur length on 1MSTST performance (B = - 1.6, 95% CI = - 2.6/- 0.7, p = 0.01), tibia length showed significant interaction with the 1MSTST modality (B = 1.2, 95% CI = 0.2/2.2, p = 0.03).

CONCLUSION

An individualisation of the 1MSTST starting position to 90° knee flexion angle leads to more repetitions compared to the traditional starting position. The higher repetition count is explained by controlling for differences in tibia length. We recommend individualisation of the 1MSTST, enabling more valid comparisons across populations and study samples.

TRIAL REGISTRATION NUMBER

http://www.

CLINICALTRIALS

gov , NCT04772417.

TRIAL REGISTRATION DATE

February 26, 2021.

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

Implications of lower extremity muscle power and force for walking and fatigability in multiple sclerosis - An exploratory pilot-study

BACKGROUND

Limitations in physical function are common in Multiple Sclerosis (MS), yet it is neither clear how muscle power implicates physical function and walking-fatigability. This pilot-study aims to investigate (1) deficits in muscle power/force alongside walking in persons with MS; (2) associations between muscle power/force and physical functions and (3) the impact of prolonged walking in muscle power/force.

METHODS

30 relapse-remitting persons with MS and 28 healthy controls performed chair rise and plantar flexion on a force platform before and after 12-minutes of intermittent walking to measure lower extremity muscle power/force. GaitRite measured walking speed. The percentage change in distance walked was also calculated. Persons with MS were classified into subgroups according to walking-fatigability and mobility disability status (Patient Determined Disease Steps).

FINDINGS

Higher deficits in muscle power compared to force were observed in persons with MS vs. healthy controls particularly in persons with MS having higher disability. Muscle power and force were associated with walking capacity, mobility disability and subjective fatigue, but not with percentage change in distance walked. Persons with MS slowed down over the course of the 12-min intermittent walking, whereas decrements in walking speed and muscle power/force (derived from chair rise) were observed in persons with MS presenting walking-fatigability only.

INTERPRETATION

Muscle power and force are impaired in persons with MS and appear to be critical for physical function in MS. This exploratory pilot study further suggests that muscle power/force from chair rise could contributes to walking-fatigability which therefore offer future treatment targets.

Raising and stabilization phase of the sit-to-stand movement better discriminate healthy elderly adults from young subjects: a pilot cross-sectional study

Background

The sit-to-stand (STS) test is usually included in the clinical assessment of balance and its instrumented analysis may support clinicians in objectively assessing the risk of falling. The aim of the present study was to assess if kinetic parameters of STS collected using a force platform, with particular focus on the raising and stabilization phase, could discriminate between young and older adults.

Methods

Twenty-four adults (age ranging from 18 to 65 years old) and 28 elderly adults (older than 65 years old) performed STS on a force platform. Data on ground reaction forces, sway, displacement and velocity of the center of pressure were gathered during the raising and the stabilization phases.

Results

elderly subjects showed significant greater global sway (146.97 vs 119.85; p < 0.05) and a higher velocity (vs 40.03 vs 34.35 mm/s; p < 0.05) of execution of STS. Between-group comparisons highlighted a greater postural sway in the raising phase (21.63 vs 13.58; p < 0.001) and a doubled sway during the stabilization phase (12.38 vs 4.98; p < 0.001).

Conclusions

The analysis of STS performed on a force platform provides further information about the age-specific pattern of STS execution. The stabilization phase of STS seems to be the more challenging for functional independent older adults and should be considered during balance assessment.Further studies are needed to confirm findings and improve generalizability of this study.