External loading alters lower extremity kinetics, kinematics, and muscle activity in a distribution-specific manner during the transition from stair descent to level walking

Biomechanical analysis of trunk and lower limbs during stair activity in patients with scoliosis

Staircases are a frequently encountered obstacle in daily life, requiring individuals to navigate ascending and descending movements that place additional demands on the trunk and lower limbs compared to walking on level surfaces. Therefore, it is crucial to examine the biomechanical characteristics of the trunk and lower limbs in individuals with scoliosis during stair activity. The aim of this study was to investigate the biomechanical differences in trunk and lower limbs during daily stair activities between patients with scoliosis and a healthy population. Additionally, the study aimed to explore the relationship between trunk abnormalities and lower limb biomechanics, providing a clinical and objective assessment basis for scoliosis. The Qualisys system, based in Gothenburg, Sweden, was employed for data collection in this study, with a sampling frequency of 150 Hz. It captured the kinematics of the trunk and lower limbs, as well as the kinetics of the lower limbs during stair ascent and descent for both the 28 individuals with scoliosis and the 28 control participants. The results indicate that scoliosis patients demonstrated significantly higher asymmetry compared to the control group in various measures during ascent and decent. These include different parts of kinematics and kinetics. Scoliosis patients demonstrate noticeable variations in their movement patterns compared to the healthy population when engaging in stair activities. Specifically, during stair ascent, scoliosis patients exhibit a seemingly more rigid movement pattern, whereas descent is characterized by an unstable pattern.

Loaded and unloaded timed stair tests as tools for assessing advanced functional mobility in people with stroke

BACKGROUND

The Timed Stair Test (TST) was originally designed to measure advanced functional mobility in patients who have undergone a total hip replacement. Its psychometric properties have not been examined systematically in people with stroke.

AIM

The aims of this study were to: 1) determine the intra-rater reliability of TST under loaded and unloaded condition; 2) identify the minimal detectable changes (MDCs) in TST completion times; 3) investigate the concurrent validity between TST completion times and stroke-specific outcome measures; and 4) determine the cut-off TST completion time to differentiate the performance between people with stroke and healthy older adults.

DESIGN

Cross-sectional study.

SETTING

A university-based rehabilitation center.

POPULATION

Ninety-four people with stroke and 34 healthy older adults.

METHODS

TSTs were conducted under loaded and unloaded conditions. Two trials of the TST for each of the two conditions were performed on the same day. The Fugl-Meyer Assessment of Lower Extremity (FMA-LE), lower-limb muscle strength test assessed by a hand held dynamometer, Berg Balance Scale (BBS), Limit of Stability (LOS) Test, Timed Up and Go (TUG) Test, and the Cantonese version of the Community Integration Measure (CIM) were also used to assess the subjects.

RESULTS

Excellent intra-rater reliability was demonstrated for TST completion times under loaded (intraclass correlation coefficient [ICC<inf>2,1</inf>]=0.991) and unloaded (ICC<inf>2,1</inf>=0.985) conditions. The MDCs in TST completion times were 6.55 seconds and 7.25 seconds under loaded and unloaded conditions, respectively. FMA-LE scores, mean strength of the affected-side dorsiflexors and plantar flexors, BBS scores, and LOS movement velocity and maximum excursion scores demonstrated fair to excellent negative correlations with TST completion times under both loaded (r=-0.314 to -0.786) and unloaded (r=-0.296 to -0.794) conditions. TUG results demonstrated good to excellent positive correlations with TST completion times under both loaded (r=0.875, P<0.001) and unloaded (r=0.872, P<0.001) conditions. The TST completion times of 26.3 seconds and 23.4 seconds under loaded and unloaded conditions, respectively, differentiated between people with stroke and healthy older adults.

CONCLUSIONS

The TST is a reliable clinical tool for evaluating advanced functional mobility in people with stroke.

CLINICAL REHABILITATION IMPACT

TST is a fast and simple test that does not require sophisticated equipment, making it suitable for busy hospital and rehabilitation settings.

Gait strategies for individuals with knee osteoarthritis when transitioning between floor and stair walking

Objective: Individuals with knee osteoarthritis are at higher risk for falls during transitions between floor and stair walking due to their reduced lower extremity function. However, the adjust gait characteristics of knee osteoarthritis subjects for dealing with stair transitions have not been explored. We aimed to investigate gait strategies in individuals with knee osteoarthritis compared to age-matched individuals without knee OA during the transition between walking on floor and stairs. Method: Gait of 30 individuals with knee osteoarthritis and 30 individuals without knee osteoarthritis during floor-to-stair and stair-to-floor walking transitions were accessed using a 3D motion capture system. Foot-tread clearance, and angles of lower extremity joints and trunk at Foot-tread clearance timepoint were analyzed by using biomechanical software (Visual 3D). Results: Compared with asymptomatic control group, the knee osteoarthritis group demonstrated no difference in vertical Foot-tread clearance and horizontal Foot-tread clearance during stair transitions. However, ankle dorsiflexion (p = 0.01) decreased, hip flexion (p = 0.02) and trunk lateral tilt (p = 0.02) increased in knee osteoarthritis group during the stair ascent transition. Moreover, trunk lateral tilt to the support side (p = 0.003) and pelvic rotation (p = 0.03) increased, while hip abduction of the swing leg (p = 0.03) decreased during the stair descent transition in individuals with knee osteoarthritis. Conclusion: Increased trunk lateral tilt and altered angle of hip may be a strategy utilized by individuals with knee OA to increase the foot clearance ability and compensate for the disease-related loss of lower extremity strength, range of motion, and balance. However, compensatory manifestations, such as the increased lateral tilt of the trunk and movement of the gravity center may enhance the risk of falls and result in more abnormal knee joint loading.

Effects of weight gaining to lower limb joint moments: a gender-specific sit-to-stand analysis

The prevalence of obesity, a worldwide health problem, is increasing. Obesity or overweight has significant effects, especially on lower limb biomechanics. Previous studies have investigated the biomechanical effects of weight gain on the knee and hip joints. These studies have been conducted on different individuals with normal weight and overweight. However, no investigation has been carried out between women and men in terms of weight gain. Females usually gain weight in the gluteal-femoral region, whereas males gain weight in the abdominal region. Due to this difference, it is thought that the effects of weight gain should be examined in a gender-specific manner. In this study, a link-segment model of the lower limb was created. Then the sit-to-stand movement was simulated according to female and male-specific weight gain scenarios. According to these results, weight gain in the abdominal region (men-specific) increases the ankle and knee joint moments more than weight gain in the gluteal-femoral region (women-specific). In obese scenarios for males and females, while the ankle and knee joint moment increases, the hip joint moment decreases. These results would be beneficial for considering biomechanical differences caused by gender-specific weight gain in rehabilitation processes and orthotic and prosthetic designs.

The Association of Obesity With Quadriceps Activation During Sit-to-Stand

OBJECTIVE

Obesity reduces voluntary recruitment of quadriceps during single-joint exercises, but the effects of obesity on quadriceps femoris muscle activation during dynamic daily living tasks, such as sit-to-stand (STS), are largely unknown. The purpose of this study was to determine how obesity affects quadriceps muscle recruitment during STS.

METHODS

In this cross-sectional study, 10 women who were lean and 17 women who were obese completed STS from a chair with arms crossed over the chest. Three-dimensional motion analysis was used to define 3 distinct phases (I-III) of the STS cycle. The electromyographic (EMG) activity of the vastus medialis, vastus lateralis, and semitendinosus was measured.

RESULTS

STS duration was greater (3.02 [SD = 0.75] seconds vs 1.67 [SD = 0.28] seconds) and peak trunk flexion angle was lower (28.9 degrees [SD = 10.4 degrees] vs 35.8 degrees [SD = 10.1 degrees]) in the women who were obese than in the women who were lean. The mean EMG activity of the knee extensors increased from phase I to phase II in both groups; however, the mean EMG activities of both the vastus medialis (32.1% [SD = 16.6%] vs 47.3% [SD = 19.6%] maximal voluntary isometric contraction) and the vastus lateralis (31.8% [SD = 19.4%] vs 47.5% [SD = 19.6%] maximal voluntary isometric contraction) were significantly lower during phase II in the women who were obese. The mean EMG activity of the semitendinosus increased throughout STS but was not significantly different between the 2 groups. Coactivation of the semitendinosus and knee extensors tended to be greater in the women who were obese but failed to reach statistical significance.

CONCLUSIONS

Knee extensor EMG amplitude was reduced in women who were obese during STS, despite reduced trunk flexion.

IMPACT

Reduced knee extensor recruitment during STS in obesity may redistribute forces needed to complete this task to other joints. Functional movement training may help improve knee extensor recruitment during STS in people who are obese.

LAY SUMMARY

People with obesity often have low quadriceps muscle strength and impaired mobility during daily activities. This study shows that women who are obese have lower voluntary recruitment of quadriceps when rising from a chair than women who are lean do, which could increase workload on hip or ankle muscles during this important daily task. Quadriceps strengthening exercises might improve the ability to rise from sitting to standing.