Effect of Ageing on Quadriceps Muscle Strength and on the Forward Shift of Center of Pressure during Sit-to-stand Movement from a Chair

The Lower Limb Stiffness, Moments, and Work Mode During Stair Descent Among the Older Adults

OBJECTIVE

Lower limb stiffness strategies and work mode changes between young and older adults during stair descent are unclear. This study investigated the effect of aging on the lower limb stiffness, moments, and joint work mode during stair descent.

DESIGN

Twenty young adults and 20 older adults were recruited from the local community for stair descent test. Kinematics and kinetics data were collected by Vicon system and Kistler force plate. The lower limb stiffness, moments, and work mode were calculated and assess between groups.

RESULTS

No significant differences in gait parameters were detected between groups. Compared with young adults, older adults have decreased leg stiffness, knee and ankle stiffness, increased peak hip extension moment, hip stiffness, and ankle work contribution.

CONCLUSIONS

The older adults actively reduce the lower limb stiffness to reduce the risk of injury during stair descent. The hip joint strategy reduces the risk of forwarding falls and ankle joint compensation work mode to make up for the lack of knee extension strength. This provides a reference for the focus of exercise intervention and rehabilitation strategies for older adults.

Investigating the Relationships Between Three Important Functional Tasks Early After Stroke: Movement Characteristics of Sit-To-Stand, Sit-To-Walk, and Walking

Background: Walking, sit-to-stand (STS) and sit-to-walk (STW) are all considered important functional tasks in achieving independence after stroke. Despite knowledge that sensitive measurement of movement patterns is crucial to understanding neuromuscular restitution, there is surprisingly little information available about the detailed biomechanical characteristics of, and relationships between, walking, sit-to-stand and sit-to-walk, particularly in the important time window early after stroke. Hence, here, the study aimed to:

Identify the biomechanical characteristics of and determine any differences in both movement fluidity (hesitation, coordination and smoothness) and duration of movement phases, between sit-to-stand (STS) and sit-to-walk (STW) in people early after stroke.

Determine whether measures of movement fluidity (hesitation, coordination, and smoothness) and movement phases during sit-to-stand (STS) and/or sit-to-walk (STW) are correlated strongly to commonly used measures of walking speed and/or step length ratio in people early after stroke.

Methods: This study consisted of secondary data analysis from the SWIFT Cast Trial. Specifically, we investigated movement fluidity using established assessments of smoothness, hesitation and coordination and the time duration for specific movement phases in a group of 48 people after stroke. Comparisons were made between STS and STW and relationships to walking measures were explored.

Results: Participants spent significantly more time in the initial movement phase, flexion momentum, during STS [mean time (SD) 1.74 ±1.45 s] than they did during STW [mean time (SD) 1.13 ± 1.03 s]. STS was also completed more smoothly but with more hesitation and greater coordination than the task of STW. No strong relationships were found between movement fluidity or duration with walking speed or step length symmetry.

Conclusions: Assessment of movement after stroke requires a range of functional tasks and no one task should predominate over another. Seemingly similar or overlapping tasks such as STS and STW create distinct biomechanical characteristics which can be identified using sensitive, objective measures of fluidity and movement phases but there are no strong relationships between the functional tasks of STS and STW with walking speed or with step-length symmetry.

The association between anthropometric, lower limb strength, and balance variables with 5-repetition sit-to-stand test performance in physically active elderly women

BACKGROUND: Sit-to-stand test is very often used as measure of lower limb strength in elderly adults. However, the recent findings indicate that performance in this test is also influenced by other factors. OBJECTIVE: To investigate the association between anthropometric, lower limb strength, and balance variables with the 5-repetition sit-to-stand test (5RSTST) in elderly women. METHODS: Forty physically active elderly women ⩾ 60 years underwent the 5RSTST and anthropometric, balance, and lower limb strength assessment. Anthropometric measurements included height and weight. Balance was quantified in the bipedal upright stance on the basis of the centre of pressure sway in the anteroposterior (CoPAP) and mediolateral (CoPML) direction. Bilateral concentric strength of the ankle plantarflexors and dorsiflexors, knee flexors and extensors, and hip extensors was measured. RESULTS: The time to complete the 5RSTST was significantly but mildly associated with height (r= 0.356, p= 0.024), ankle dorsiflexor strength (r=-0.413, p= 0.017), knee flexor strength (r=-0377, p= 0.030), knee extensor strength (r=-0.411, p= 0.017), hip flexor strength (r=-0.359, p= 0.040) on dominant limb, and balance in both directions (AP, r= 0.651, p< 0.001; ML, r= 0.647, p< 0.001). Balance control in AP direction and knee extensor strength on dominant limb were the only factors that contributed independently to 5RSTST, accounting for 55% of the variance. Balance control in AP direction alone explained 41% of the variance in 5RSTST. CONCLUSIONS: Balance control in AP seems to be the most important factor explaining the 5RSTST performance.

The effect of a hybrid assistive limb(®) on sit-to-stand and standing patterns of stroke patients

[Purpose] The Hybrid Assistive Limb(®) (HAL(®)) robot suit is a powered exoskeleton that can assist a user's lower limb movement. The purpose of this study was to assess the effectiveness of HAL(®) in stroke rehabilitation, focusing on the change of the sit-to-stand (STS) movement pattern and standing posture. [Subjects and Methods] Five stroke patients participated in this study. Single leg HAL(®) was attached to each subject's paretic lower limb. The subjects performed STS three times both with and without HAL(®) use. A tri-axial accelerometer was used to assess the STS movement pattern. Forward-tilt angle (FTA) and the time required for STS were measured with and without HAL(®) use. Surface electromyography (EMG) of STS and standing were recorded to assess the vastus medialis muscle activities of the paretic limb. [Results] The average FTA without HAL(®) use was 35° and it improved to 43° with HAL(®) use. The time required for STS was longer for all subjects with HAL(®) use (without HAL(®) use: 3.42 s, with HAL(®) use: 5.11 s). The integrated EMGs of HAL(®) use compared to those without HAL(®), were 83.6% and 66.3% for STS and standing, respectively. [Conclusion] HAL(®) may be effective in improving STS and standing patterns of stroke patients.

The sitting and rising test for assessing people with chronic stroke

[Purpose] To investigate the inter-rater and test-retest reliability of the sitting-rising test (SRT), the correlations of sitting-rising test scores with measures of strength, balance, community integration and quality of life, as well as the cut-off score which best discriminates people with chronic stroke from healthy older adults were investigated. [Subjects and Methods] Subjects with chronic stroke (n=30) and healthy older adults (n=30) were recruited. The study had a cross-sectional design, and was carried out in a university rehabilitation laboratory. Sitting-rising test performance was scored on two occasions. Other measurements included ankle dorsiflexor and plantarflexor strength, the Fugl-Meyer assessment, the Berg Balance Scale, the timed up and go test, the five times sit-to-stand test, the limits of stability test, and measures of quality of health and community integration. [Results] Sitting-rising test scores demonstrated good to excellent inter-rater and test-retest reliabilities (ICC=0.679 to 0.967). Sitting-rising test scores correlated significantly with ankle strength, but not with other test results. The sitting-rising test showed good sensitivity and specificity. A cut-off score of 7.8 best distinguished healthy older adults from stroke subjects. [Conclusions] The sitting-rising test is a reliable and sensitive test for assessing the quality of sitting and rising movements. Further studies with a larger sample are required to investigate the test’s validity.

Effect of arm position and foot placement on the five times sit-to-stand test completion times of female adults older than 50 years of age

The five times-sit-to stand test (FTSTS) is a clinical test which is commonly used to assessed the functional muscle strength of the lower limbs of older adults. The aim of this study was to examine the effect of different arm positions and foot placements on the FTSTS completion times of older female adults. [Subjects and Methods] Twenty-nine healthy female subjects, aged 63.1±5.3 years participated in this cross-sectional study. The times required to complete the FTSTS with 3 different arm positions (hands on thighs, arms crossed over chest, and an augmented arm position with the arms extended forward) and 2 foot placements (neutral and posterior) were recorded. The interaction effect and main effect of arm positions and foot placements were examined using a 3 (arm position) × 2 (foot placement) two-way repeated measures analysis of variance (ANOVA). [Results] There was no interaction effect among the 3 arm positions in the 2 foot placements. A significant main effect was identified for foot placement, but not arm position. Posterior foot placement led to a shorter FTSTS time compared to that of normal foot placement. [Conclusion] With the same arm position, FTSTS completion times with posterior foot placement tended to be shorter. Therefore, the standard foot placement should be used for FTSTS administration.

Aerobic and resistance exercise training program intervention for enhancing gait function in elderly and chronically ill Taiwanese patients

OBJECTIVES

This study aimed to develop an effective exercise training program for enhancing the postural stability and gait function of chronically ill patients to avoid falls.

STUDY DESIGN

Pre training-post-training. Analyses were limited to those randomized to the exercise intervention.

METHODS

The participants were chronically ill patients over 45 years old (47-89 years), of whom 25 completed the 12-week training regimen and assessment in the exercise group, whereas 29 completed the assessment in the control group, suffering from cardiovascular disease, diabetes mellitus, or osteoporosis. The average age of the participants was 67.56 ± 10.70 years in the intervention group. All patients in this study signed institutional review board (IRB) agreements before participating (IRB approval no: FEMH-IRB-101029-E, v. 02, date: 20120429).

RESULTS

The results revealed the beneficial effects of regular aerobic and resistance training, which improved in elderly, chronically ill patients. According to our data, most of the gait function measurements exhibited significant differences between the exercise group and control group. The duration of the 'timed up-and-go' test decreased from 7.67 s to 6.76 s (P = 0.00013), and the 'the base of support area' increased from 392.0 cm(2) to 433.2 cm(2) (P = 0.0088). Women attained more significant differences than men in the exercise and control groups (P = 0.0008), and the participants aged 45-65 years had a more satisfactory outcome than those aged > 65 years (P = 0.0109).

CONCLUSION

Regular exercise regimens, such as aerobic, resistance or combination exercise training, enhance the gait function and sense of postural stability in elderly, chronically ill patients. Younger patients attained more positive results than older patients, and women attained more positive results than men. Regular exercise is a means of preventing falls; thus, the government and hospitals should increase promotional measures in aging communities to encourage regular exercise among elderly, chronically ill outpatients.

Relationship between the ability to perform the sit-to-stand movement and the maximum pelvic anteversion and retroversion angles in patients with stroke

[Purpose] The purpose of this study was to investigate the relationship between the ability to perform the sit-to-stand movement and the maximum pelvic anteversion and retroversion angles of patients. [Subjects] Thirty-two stroke patients (66.7±7.6 years) (>3 months post-stroke) who were able to sit unsupported and 50 age-matched healthy subjects participated in this study. The stroke patients were classified into two groups according to the sit-to-stand movement test: the group that was able to stand up (the stand-able group) (18 persons) and the group that was unable to stand up (the stand-unable group) (14 persons). [Methods] Pelvic anteversion and retroversion maximum angles were measured by a manual goniometer attached to an inclinometer. [Results] The maximum pelvic anteversion angles were −1.6 ± 5.0°, 1.2 ± 2.8°, and −12.4 ± 6.1° in the control group, the stand-able stroke group, and the stand-unable stroke group, respectively. A significant main effect of group was found. An angle discriminating between the two stroke groups was found: the maximum anteversion angles in the stand-able group were distributed above −5°. [Conclusion] The maximum pelvic anteversion angle was significantly smaller in the stand-unable group than in the stand-able and control groups.

The effects of vision on sit-to-stand movement

[Purpose] It is well known that vision is an important factor contributing to postural control. However, there has been little discussion about the effect of vision on sit-to-stand movement. The purpose of this study was to evaluate the effect of constrained vision on sit-to-stand movement. [Subjects and Methods] Twenty-three healthy subjects (11 males, 12 females) aged 18-23 years with normal body mass indices were recruited for this study. Each participant was asked to stand as quickly as possible from a height-adjustable chair 3 times under 2 conditions: with eyes closed (EC) and eyes open (EO). The weight transfer time, rising index, and center of gravity sway velocity were measured using a NeuroCom Balance Master. [Results] The results show there were significant differences between the EC and EO conditions in the weight transfer time and the centre of gravity sway velocity. No significant difference was found between the EC and EO conditions in the rising index. These findings suggest that visual perception may play a role in balance control while performing sit-to-stand movement.

Characterizing asymmetry across the whole sit to stand movement in healthy participants

Sit-to-stand transfer (STS) is a common yet critical prerequisite for many daily tasks. Literature conducted on healthy STS often assume the body to behave symmetrically across the left and right side; yet only a few studies have been conducted to investigate this supposition. These studies have focused on a single numerical indicator such as peak joint moment (JM) values to describe symmetricity; however, STS is a dynamic and time dependent movement. This study addresses the validity of peak value analyses through the introduction of a time based peak-offset measure and proposes two time-dependent techniques to further characterize asymmetry and assesses their feasibility in ten (10) healthy male participants. JM and joint power (JP) over the whole STS movement was determined using motion capture and inverse dynamics. Using a paired one-tailed t-test differences were found in the time at which the left and right side reached peak values in all lower extremity joints (p<0.05) with exception of the hip JM. Using a measure of JM and JP straight-difference it was determined that the ankle joint displayed the largest number of JM and JP development strategies of all the lower extremity joints. Finally, through numerical integration of the JM and JP data with respect to time, it was found that the longer one side spends dominating the movement, the larger the excess angular impulse and work that can be expected from that side. The results suggest that when analyzing STS movements, one must be aware of the potential asymmetry present even in healthy movements. Furthermore, a simple peak JM or JP analysis may not fully describe the extent of these asymmetries.