Modified electromyography-assisted optimization approach for predicting lumbar spine loading while walking with backpack loads.

This study modified an electromyography-assisted optimization approach for predicting lumbar spine loading while walking with backpack loads. The modified-electromyography-assisted optimization approach eliminated the electromyography measurement at maximal voluntary contraction and adopted a linear electromyography-force relationship. Moreover, an optimal lower boundary condition for muscle gain was introduced to constrain the trunk muscle co-activation. Anthropometric information of 10 healthy young men as well as their kinematic, kinetic, and electromyography data obtained while walking with backpack loads were used as inputs in this study. A computational algorithm was used to find and analyse the sensitivity of the optimal lower boundary condition for achieving minimum deviation of the modified-electromyography-assisted optimization approach from the electromyography-assisted optimization approach for predicting lumbosacral joint compression force. Results validated that the modified-electromyography-assisted optimization approach (at optimal lower boundary condition of 0.92) predicted on average, a non-significant deviation in peak lumbosacral joint compression force of -18 N, a standard error of 9 N, and a root mean square difference in force profile of 73.8 N. The modified-electromyography-assisted optimization approach simplified the experimental process by eliminating the electromyography measurement at maximal voluntary contraction and provided comparable estimations for lumbosacral joint compression force that is also applicable to patients or individuals having difficulty in performing the maximal voluntary contraction activity.

Effects of asymmetric loading on lateral spinal curvature in young adults with scoliosis: A preliminary study.

BACKGROUND: Usual guidelines recommend symmetric load carriage over asymmetric load carriage. Whether this recommendation is valid for subjects with asymmetric body alignment, such as those with scoliosis, remains unclear. Scoliosis is both a subject-dependent and time-variant condition. Interventions are generally employed to prevent the abnormal spinal curvature from progressing. OBJECTIVES: To investigate the effects of an asymmetric load carriage on lateral spinal deformity in participant with scoliosis. STUDY DESIGN: Repeated measure and single-case experimental designs Methods: Photogrammetry was employed to measure the scoliotic curvature changes in thoracic and lumbar regions without a load (0%) and with a single-strap cross-chest bag loaded at 2.5%, 5%, 7.5%, 10% and 12.5% of body weight. Statistical tests and programming models were adopted to determine the loading conditions (placement and weight of the bag) with optimal and minimal corrections of the affected and unaffected scoliotic spinal regions, respectively. RESULTS: Significant short-term postural correction of scoliosis was achieved through applying an asymmetric load on the ipsilateral shoulder relative to the apex location of the major scoliotic curve. CONCLUSION: A subject-specific optimal loading configuration was determined using a programming model. The results suggest that the application of a properly controlled asymmetric load carriage might be possible for reducing scoliotic spinal curvature. Further study of the long-term effects of subject-specific optimal asymmetric load carriage on scoliotic spinal curvatures is warranted. Clinical relevance Short-term reduction of scoliotic spinal curvatures under asymmetric load carriage was demonstrated. Thoracic curvatures could be reduced when asymmetric loading was applied on the ipsilateral shoulder relative to the scoliotic apex. Multiobjective programming was applied to determine the optimal weight of asymmetric load for participant with scoliosis.

Effects of kneeling posture on chest compression during cardiopulmonary resuscitation in males.

AIMS AND OBJECTIVES: To study the effects of kneeling posture on chest compression during cardiopulmonary resuscitation (CPR) in males. BACKGROUND: Efficiency of chest compression during CPR affected millions of victims over the world. There are still no clear guidelines on kneeling posture that a rescuer should adopt in performing CPR. DESIGN: A self-controlled repeated-measures design was applied in this study. The efficiency of chest compression on a mannequin when three kneeling postures were adopted (farthest, self-adjusted and nearest) was analysed. METHODS: Eighteen participants with qualified first-aid certificate were recruited. Each participant had to perform three sessions of CPR, using one of the three different kneeling postures (i.e., farthest, self-adjusted and nearest) in each. They were performed in a random order chosen by drawing lots. Each session consisted of five cycles of CPR in each kneeling posture. Each cycle consisted of 30 strokes of chest compression performed within 18 s with a 4-s pause between consecutive cycles. Each session lasted for 2 min. The participants were allowed to rest for 10 min on a chair between sessions. Efficiency of chest compression was quantified by compression force, joint angle, heart rate and energy expenditure. After each session of CPR, the participants were surveyed about their rate of perceived exertion. RESULTS: Efficiency of chest compression in self-adjusted and nearest kneeling postures was significantly better than that of the farthest one. While the self-adjusted and nearest postures had the similar effect, most of the participants preferred self-adjusted kneeling posture because of lower rate of perceived exertion. CONCLUSION: The use of the self-adjusted and nearest kneeling postures during CPR in males resulted in more effective chest compression with lower perceived exertion, compared with the farthest kneeling posture. Both these positions can be objectively recommended to enhance the efficiency of chest compression and thereby increase the cardiac arrest survival rate. RELEVANCE TO CLINICAL PRACTICE: More consistent force and higher endurance could be achieved by performing CPR at self-adjusted kneeling posture.

A simplified emergency trauma score for predicting mortality in emergency setting.

AIMS: The aim of the study was to develop a simplified emergency trauma score (SETS) for rating injury severity as well as triaging and predicting mortality in Hong Kong. BACKGROUND: Many existing trauma scoring systems require measurements that are not generally available in emergency settings in Hong Kong. As many of these important measures in the scoring systems are not available before the patients are admitted in the hospitals, it may delay treatment because of the extent of a patient's injury is often not clear at the site of accident or in the emergency settings. DESIGN: A retrospective cohort analysis of trauma patients' records from Trauma Registry in Hong Kong was performed. METHOD: Potential significant parameters in predicting mortality were identified by univariate analysis. Binary logistic regression then was used to develop an equation for SETS. Four parameters including age, Glasgow coma scale, respiratory rate and American College of Surgeons (ACS) mechanism of injury were identified, and the reliability and validity of SETS was assessed. RESULTS: At cut-off point of a SETS score of 60, the sensitivity and specificity of SETS were 64% and 98% respectively. The area under receiver operating characteristic curve was 0·939 which was comparable with other commonly used trauma scores. CONCLUSIONS: SETS should be considered a relevant trauma scoring system in Hong Kong emergency settings. It is suggested that similar scoring systems should be developed in other countries based upon obtainable measures in their corresponding emergency settings. RELEVANCE TO CLINICAL PRACTICE: As a trauma scoring system is closely related to the context of its application, a system that can facilitate accurate sorting of patients into treatment hierarchies should be adopted in the congested emergency settings.

Effects of body mass index and full body kinematics on tennis serve speed.

Effective training to improve serve speed is important for competitive tennis players. The purposes of this study were to investigate the effects of anthropometric factors and whole body kinematics of elite players on ball speed and to propose possible training strategies for improving the quality of tennis serves. Body and racket kinematics of tennis serves of 12 male elite Hong Kong players were investigated. The tennis serve was divided into four phases: I) Back-Swing Phase, II) Lead-Leg-Drive Phase, III) Forward-Swing Phase, and IV) Follow-Through Phase. It was shown that racket-side knee range of motion during phases II and III (r=0.705; p<0.05), racket-side knee peak extension velocity during phase II (r=0.751; p<0.01), racket-side hip peak extension velocity during phase II (r=0.657; p<0.05), racket-side shoulder range of motion in the coronal plane during phase III (r=0.616; p<0.05), racket-side elbow peak extension velocity during phase III (r=0.708; p<0.01) and body mass index (r=0.577; p<0.05) were significantly correlated with ball speed. Body mass index and the identified kinematic parameters that were significantly correlated with ball speed could be used as training guidelines for coaches and players to improve serve speed. Players should pay particular attention in training to increasing the extension velocity and range of motion of the identified joints.

Kinematic and electromyographic studies on unaided, unilateral and bilateral crutch walking in adolescents with spastic diplegia.

BACKGROUND: Back pain and ambulation deterioration among ambulatory individuals with cerebral palsy (CP) are common as they grow older and walking aids are often prescribed to improve stability and promote maximal weight-bear on lower limbs during gait. OBJECTIVE: To investigate the effects of walking aids on back muscle activity and whole body kinematics among adolescents with spastic diplegia. STUDY DESIGN: A repeated-measures design was adopted with participants tested under different walking conditions. METHODS: Ten participants were recruited and Lofstrand forearm crutches were selected. Both the activity of lumbar erector spinae and the kinematics of head, trunk, pelvis and lower limbs during walking were monitored using telemetric electromyography and motion analysis system respectively. RESULTS: Comparisons between walking unaided and walking with unilateral and bilateral crutch(es) were made. Significant decreases in speed, cadence, erector spinae activity and lower trunk extension were observed during crutch walking together with significantly increased stride time and anterior pelvic tilt. CONCLUSIONS: These findings suggested that Lofstrand crutch(es) reduced muscular demands and lumbar lordosis with increased lower back mobility. The results shed light on the prescription of walking aid in the management and prevention of chronic back pain for ambulatory individuals with CP from a life span perspective.

Early physiotherapy intervention in an Accident and Emergency Department reduces pain and improves satisfaction for patients with acute low back pain: a randomised trial.

QUESTION: What is the effect of early physiotherapy intervention on pain and patient satisfaction in acute low back pain? DESIGN: Randomised trial with concealed allocation, assessor blinding, and intention-to-treat analysis. PARTICIPANTS: 110 patients attending the Accident and Emergency Department of a local acute hospital. INTERVENTION: The experimental group received early physiotherapy intervention which consisted of education, reassurance, pain management, mobility training, interferential therapy, walking training, and walking aids as indicated. The control group received only walking training and walking aids as indicated. All participants received conventional medical intervention and outpatient physiotherapy intervention. OUTCOME MEASURES: Pain was measured using the Numeric Pain Rating Scale and satisfaction was measured using the Numeric Global Rating of Change Scale at baseline, discharge from the Accident and Emergency Department, admission to the Physiotherapy Outpatient Department, 1 month, 3 months, and 6 months. RESULTS: Participants in the experimental group had 1.6 out of 10 points (97.5% CI 0.8 to 2.3) less pain than the control group on discharge from the Accident and Emergency Department and still had 0.9 points (97.5% CI 0.1 to 1.6) less pain on admission to the Physiotherapy Outpatient Department. Participants in the experimental group were 2.1 out of 20 points (97.5% CI 1.2 to 2.9) more satisfied than the control group on discharge from the Accident and Emergency Department. CONCLUSION: Early physiotherapy intervention was effective in reducing pain and increasing satisfaction for patients with acute low back pain in an Accident and Emergency Department but the effect tailed off.