Changes In Trunk Angle Research Articles

Gait Kinematics and Asymmetries Affecting Fall Risk in People with Chronic Stroke: A Retrospective Study

Stroke survivors are at a relatively higher risk of falling than their healthy counterparts. To identify the key gait characteristics affecting fall risk in this population, this study analyzed the gait kinematics and gait asymmetries for 36 community-dwelling people with chronic stroke (PwCS). According to their fall history in the last 12 months, they were divided into a fall group (n = 21) and non-fall group (n = 15), and then the gait kinematics (step length, stride length, stance time, swing time, trunk angle, and segment angles for lower limbs) and their asymmetries (symmetry ratio and symmetry index) were compared between these two groups. To investigate the relationship between fall types and gait characteristics, these variables were also compared between 11 slip-fallers and non-fallers, as well as between 7 trip-fallers and non-fallers. Our results indicated that the fallers showed smaller trunk and thigh angle, larger shank angle, and higher gait asymmetries (trunk and foot). Such changes in gait pattern could also be found in the trip-fallers, except the trunk angle. Additionally, the trip-fallers also showed a shorter step length, shorter stride length, shorter swing time, larger foot angle on the paretic side, and higher asymmetries in shank angle and step length, while the slip-fallers only showed changes in trunk angle and thigh angle and higher asymmetries in step length and foot angle compared to the non-fall group. Our results indicated that improper or pathological gait patterns (i.e., smaller thigh angle or higher foot asymmetry) increases the risk of falling in PwCS, and different fall types are associated with different gait characteristics. Our findings would be helpful for the development of fall risk assessment methods that are based on kinematic gait measurements. Implementation of objective fall risk assessments in PwCS has the potential to reduce fall-related injuries, leading to a reduction in associated hospital costs.

Effect of Trunk Position on Trapezius Muscle Activity and Ratio during Performing Modified Seated Cable Row Exercise

Background Changes in trunk angle as part of modifying the seated cable row exercise (MSCRE) are associated with trapezius muscle activity and ratio. Purpose This study aimed to determine the changes in muscle activity and ratio for the upper trapezius (UT), middle trapezius (MT), and lower trapezius (LT) muscles during the MSCRE in healthy participants without shoulder pain. Study design Cross-sectional study Methods We included participants who were 23 healthy individuals aged 23–39 years. The participants performed a pulling motion three times during the MSCRE at each of the following trunk angles: upright posture 0°, forward lean 30°, and backward lean 20°. Surface electromyography was performed for the UT, MT, and LT muscles during the 5-s isometric contraction, with the participant in a preset position, while the muscle activity was normalized with the maximal voluntary isometric contraction using the manual muscle test. Results The UT and LT muscle activities showed significant differences in angle (<italic>p</italic>&lt;0.05); the highest muscle activity was observed for the UT at backward lean 20° and LT at forward lean 30°. The UT/MT and UT/LT ratios showed significant differences in angle (<italic>p</italic>&lt;0.05), with the highest values observed at backward lean 20° for both the ratios. Conclusions These results suggest that the forward lean 30° trunk angle was most suitable for the MSCRE in the selective strengthening of the LT muscle, indicating that the trunk should be tilted forward during exercise for normal and balanced recovery of trapezius muscle activities in shoulder rehabilitation.

Proximal and distal muscle fatigue differentially affect movement coordination.

Muscle fatigue can cause people to change their movement patterns and these changes could contribute to acute or overuse injuries. However, these effects depend on which muscles are fatigued. The purpose of this study was to determine the differential effects of proximal and distal upper extremity muscle fatigue on repetitive movements. Fourteen subjects completed a repetitive ratcheting task before and after a fatigue protocol on separate days. The fatigue protocol either fatigued the proximal (shoulder flexor) or distal (finger flexor) muscles. Pre/Post changes in trunk, shoulder, elbow, and wrist kinematics were compared to determine how proximal and distal fatigue affected multi-joint movement patterns and variability. Proximal fatigue caused a significant increase (7°, p < 0.005) in trunk lean and velocity, reduced humeral elevation (11°, p < 0.005), and increased elbow flexion (4°, p < 0.01). In contrast, distal fatigue caused small but significant changes in trunk angles (2°, p < 0.05), increased velocity of wrench movement relative to the hand (17°/s, p < 0.001), and earlier wrist extension (4%, p < 0.005). Movement variability increased at proximal joints but not distal joints after both fatigue protocols (p < 0.05). Varying movements at proximal joints may help people adapt to fatigue at either proximal or distal joints. The identified differences between proximal and distal muscle fatigue adaptations could facilitate risk assessment of occupational tasks.

Optimal gait retraining strategies in patients with knee osteoarthritis

Main topics: Rehabilitation; Experimental studies in human movement science Introduction and aim: Progression of knee osteoarthritis (OA) seems related to a high external knee adduction moment (EKAM) during gait [1,2], which can be reduced by gait retraining [3]. In healthy adults, lateral trunk lean and medializing the knee during gait reduce the EKAM effectively, although the optimal strategy seems individually dependent [3]. We aimed to determine which strategy reduces the EKAM most in patients with knee OA, and if the same strategy is most effective for all patients. Patients/materials and methods: Twenty-eight patients with radiographically diagnosed medial tibio-femoral knee OA underwent 3D gait analysis. Comfortable walking, lateral trunk lean towards the affected leg during the stance phase (Trunk Lean), and medializing the knee at initial contact (Medial Thrust) were investigated. Knee moments and kinematics of the knee and the trunk were calculated. Gait retraining strategies were assessed by comparison of EKAMpeak and impulse relative to comfortablewalking. Results: Most patients (age: 60.1±6.1 years, height: 1.71±0.10m, weight: 77.9±12.7 kg, mean KOOS-score: 46.3, KOOS subscales: pain (55.5), symptoms (52.5), daily activities (60.8), sport/recreation (26.8), knee-related QoL (36)) could finish the protocol without reporting any difficulties. One patient could not perform Medial Thrust due to knee pain. Fig. 1 shows the EKAM for all conditions. In both retraining strategies, EKAM was reduced significantly for early stance peak (MT: −0.07±0.01Nm/Bw·Ht, TL: −0.08±0.01Nm/Bw·Ht) and impulse (MT: −0.18±0.01Nms/Bw·Ht, TL: −0.03±0.01Nms/Bw·Ht). In 15 patients, Trunk Lean reduced overall EKAM peak the most (−0.09±0.04Nm/Bw·Ht). In 12 patients this was true for Medial Thrust (−0.13±0.07Nm/Bw·Ht). In the Medial Thrust group, leaning the trunk was significantly less effective than medializing the knee (p=0.005). In the Trunk Lean group, medializing the knee was significantly less effective than leaning the trunk (p=0.001). Changes in trunk angle and knee adduction angle as a result of retraining were similar between the groups (p>0.288). Discussion and conclusions: Medial Thrust and Trunk Lean effectively reduce the early stance EKAM peak and impulse during gait in patients with medial tibio-femoral knee OA. Even if the gait retraining instructions are not executed differently, the effectiveness of gait retraining strategies in reducing peak EKAM depends Fig. 1. EKAM for all conditions. Grey areas represent 95% CI for Normal Walking.

User-Based Motion Sensing and Fuzzy Logic for Automated Fall Detection in Older Adults

More than one third of community-dwelling older adults and up to 60% of nursing home residents fall each year, with 10-15% of fallers sustaining a serious injury. Reliable automated fall detection can increase confidence in people with fear of falling, promote active safe living for older adults, and reduce complications from falls. The performance of a 2-stage fall detection algorithm using impact magnitudes and changes in trunk angles derived from user-based motion sensors was evaluated under laboratory conditions. Ten healthy participants were instrumented on the front and side of the trunk with 3D accelerometers. Participants simulated 9 fall conditions and 6 common activities of daily living. Fall conditions were simulated on a protective mattress. The experimental data set comprised 750 events (45 fall events and 30 nonfall events per participant) that were classified by the fall detection algorithm as either a fall or a nonfall using inputs from 3D accelerometers. Significant differences for impacts recorded, trunk angle changes (p<0.01), and detection performances (p<0.05) were found between fall and nonfall conditions. The proposed algorithm detected fall events during simulated fall conditions with a success rate of 93% and a false-positive rate of 29% during nonfall conditions. Despite a slightly superior identification performance for the accelerometer located on the front of the trunk, no significant differences were found between the two motion sensor locations. Automated detection of fall events based on user-based motion sensing and fuzzy logic shows promising results. Additional rules and optimization of the algorithm will be needed to decrease the false-positive rate.

A threshold-based fall-detection algorithm using a bi-axial gyroscope sensor

A threshold-based algorithm, to distinguish between Activities of Daily Living (ADL) and falls is described. A gyroscope based fall-detection sensor array is used. Using simulated-falls performed by young volunteers under supervised conditions onto crash mats and ADL performed by elderly subjects, the ability to discriminate between falls and ADL was achieved using a bi-axial gyroscope sensor mounted on the trunk, measuring pitch and roll angular velocities, and a threshold-based algorithm. Data analysis was performed using M atlab ® to determine the angular accelerations, angular velocities and changes in trunk angle recorded, during eight different fall and ADL types. Three thresholds were identified so that a fall could be distinguished from an ADL: if the resultant angular velocity is greater than 3.1 rads/s (Fall Threshold 1), the resultant angular acceleration is greater than 0.05 rads/s 2 (Fall Threshold 2), and the resultant change in trunk-angle is greater than 0.59 rad (Fall Threshold 3), a fall is detected. Results show that falls can be distinguished from ADL with 100% accuracy, for a total data set of 480 movements.

Body Configuration in Cycling Affects Muscle Recruitment and Movement Pattern

By manipulating trunk angle in ergometer cycling, we studied the effect of body configuration on muscle recruitment and joint kinematics. Changing trunk angle affects the length of muscles that span the hip joint. It is hypothesized that this affects the recruitment of the muscles directly involved, and as a consequence of affected joint torque distributions, also influences the recruitment of more distal muscles and the kinematics of distal joints. It was found that changing the trunk from an upright position to approximately 20 deg forward or backward affected muscle activation patterns and kinematics in the entire lower limb. The knee joint was the only joint not affected by manipulation of the lengths of hip joint muscles. Changes in trunk angle affected ankle and hip joint kinematics and the orientation of the thigh. A similar pattern has been demonstrated for muscle activity: Both the muscles that span the hip joint and those acting on the ankle joint were affected with respect to timing and amplitude of EMG. Moreover, it was found that the association between muscle activity and muscle length was adapted to manipulation of trunk angle. In all three conditions, most of the muscles that were considered displayed some eccentric activity. The ratio of eccentric to concentric activity changed with trunk angle. The present study showed that trunk angle influences muscle recruitment and (inter)muscular dynamics in the entire limb. As this will have consequences for the efficiency of cycling, body configuration should be a factor in bicycle design.

Trunk extension strength and muscle activity in standing and kneeling postures.

A split-plot experimental design was used to evaluate the influence of posture, trunk angle, and rotational velocity on peak torque output and myoelectric activity during maximal trunk extension maneuvers. To determine whether the kneeling posture alters extension torque capabilities in isometric and isokinetic exercises as compared with standing. Also, to ascertain whether recruitment of trunk muscles is modified by such a postural change. Factors such as workplace geometry may force workers to adopt awkward or unusual postures in the performance of manual tasks. An understanding of the limitations placed on strength in unconventional working postures is crucial to the proper design of jobs. Twenty-one healthy male subjects (mean age = 36 years +/- 7 SD) performed 12 trunk extension exertions in standing and kneeling postures. Isometric tests were performed at 22.5 degrees, 45 degrees, and 67.5 degrees of trunk flexion. Isokinetic tests were done at three velocities: 30 degrees/sec, 60 degrees/sec, and 90 degrees/sec. Electromyographic data were collected from eight trunk muscles to assess muscle recruitment under each condition. A priori orthogonal contrasts were specified for analysis of both torque and electromyographic data. The kneeling posture was associated with a 15% decrease in peak torque output when contrasted with standing: however, no concomitant change in trunk muscle activity was evident. Trunk hyperflexion (isometric tests) and increasing rotational velocity (isokinetic tests) were associated with reduced torque in both postures. Trunk muscle activity was primarily affected by changes in trunk angle and velocity of contraction. A reduced extensor capability exists in the kneeling posture, despite equivalent trunk muscle activity. The similar activation patterns in both postures suggest that the strength deficit does not result from alterations in trunk muscle function. Rather, it may be the consequence of a reduced capability to rotate the pelvis in the kneeling posture, due to a disruption of the biomechanical linkage of the leg structures.