Metagenomic next-generation sequencing for the identification of infections caused by Gram-negative pathogens and the prediction of antimicrobial resistance.

OBJECTIVE: The aim of this study was to evaluate the efficacy of metagenomic next-generation sequencing (mNGS) for the identification of Gram-negative bacteria (GNB) infections and the prediction of antimicrobial resistance. METHODS: A retrospective analysis was conducted on 182 patients with diagnosis of GNB infections who underwent mNGS and conventional microbiological tests (CMTs). RESULTS: The detection rate of mNGS was 96.15%, higher than CMTs (45.05%) with a significant difference (χ 2 = 114.46, P < .01). The pathogen spectrum identified by mNGS was significantly wider than CMTs. Interestingly, the detection rate of mNGS was substantially higher than that of CMTs (70.33% vs 23.08%, P < .01) in patients with but not without antibiotic exposure. There was a significant positive correlation between mapped reads and pro-inflammatory cytokines (interleukin-6 and interleukin-8). However, mNGS failed to predict antimicrobial resistance in 5 of 12 patients compared to phenotype antimicrobial susceptibility testing results. CONCLUSIONS: Metagenomic next-generation sequencing has a higher detection rate, a wider pathogen spectrum, and is less affected by prior antibiotic exposure than CMTs in identifying Gram-negative pathogens. The mapped reads may reflect a pro-inflammatory state in GNB-infected patients. Inferring actual resistance phenotypes from metagenomic data remains a great challenge.

Six-Week Remodeled Bike Pedal Training Improves Dynamic Control of Lateral Shuffling in Athletes With Functional Ankle Instability.

BACKGROUND: Remodeled bicycle pedal training with multidirectional challenges through muscle strengthening and neuromuscular facilitation may increase dynamic postural control and performance during lateral shuffling for athletes with functional ankle instability (FAI). HYPOTHESIS: The 6-week remodeled bicycle pedal training is effective on the ankle joint control and muscle activation, and especially that of the ankle evertor muscle co-contraction to improve dynamic postural control during lateral shuffling for athletes with FAI. STUDY DESIGN: Laboratory randomized controlled trial. LEVEL OF EVIDENCE: Level 2. METHODS: Fourteen healthy athletes (healthy group) and 26 athletes with FAI aged 18 to 30 years were included in the study. The athletes with FAI were randomly assigned to either the training group (FAI-T group) or the nontraining group (FAI-NT group). The athletes in the FAI-T group underwent 6 weeks of remodeled bicycle pedal training, whereas those in the FAI-NT group did not undergo any intervention. Muscle co-contraction index and muscle activation in the initial contact (IC) and propulsion phases, and ankle joint angle in the IC and propulsion phases were measured during lateral shuffling before and after 6 weeks of training. RESULTS: After remodeled bicycle pedal training, the FAI-T group demonstrated greater muscle activation in the hamstring (P = 0.01), greater muscle coactivation of the tibialis anterior (TA) and the peroneus longus (P = 0.01), and greater ankle eversion angle in the IC phase. Significantly greater muscle activation of the TA (P = 0.01), greater coactivation of quadriceps and hamstring (P = 0.03), and a smaller ankle inversion angle (P = 0.04) in the propulsion phase were observed in the FAI-T group after training compared with those in the FAI-NT group. CONCLUSION: Remodeled bicycle pedal training facilitates the TA and peroneus longus activation and the coactivation of the quadriceps and hamstring muscles during lateral shuffling and resulted in enhanced ankle and knee joint stability. In addition, a better ankle movement strategy during a dynamic task can be achieved via a 6-week remodeled pedal training program. CLINICAL RELEVANCE: This remodeled bicycle pedal training can be effective for rehabilitating athletes with FAI to recover lateral dynamic movement capability.

Effect of Novel Remodeled Bicycle Pedal Training on Balance Performance in Athletes With Functional Ankle Instability.

CONTEXT: Appropriate training without risk of injury is a critical concern for athletes. Remodeled bicycle pedal training with multi-directional challenges may be effective in improving the balance performance of athletes with functional ankle instability (FAI). OBJECTIVE: To evaluate the effects of 6-week modified bicycle pedal training on the balance ability and proprioception of athletes with FAI. DESIGN: Randomized controlled trial. SETTING: University motion analysis laboratory. PARTICIPANTS: Fourteen healthy athletes (healthy group) and twenty-six athletes with FAI and an age of 18 to 30 years old. The participants with FAI were randomly distributed to two groups, designated as the training group (AI-T group) and non-training group (AI-NT group), respectively. The athletes in the AI-T group received 6-week remodeled bicycle pedal training, while those in the AI-NT group received no intervention at all. INTERVENTION: A 6-week training using modified bicycle pedal capable of moving freely during loading cycle vs no intervention. MAIN OUTCOME MEASURES: The passive ankle joint position sense (JPS) in four angles and the center of pressure (COP) parameters were analyzed during single-leg standing with and without vision, respectively. RESULTS: A 6-week remodeled pedal training: (1) significantly improved the passive JPS of ankle in all directions (P < 0.05); (2) reduced the excursion of the COP in the medial-lateral (ML) direction (p < 0.05), the velocity of the COP in the ML direction (p < 0.05), and the RMS of the COP in the ML direction (P < 0.05) during single-leg standing both with and without vision. CONCLUSION: The remodeled bicycle pedal training improved the passive JPS and reduced the postural sway in single-leg standing both with and without vision. Therefore, remodeled bicycle pedal training can be considered for inclusion in rehabilitation programs for athletes with FAI to restore the proprioception and balance ability.

Effect of Loading Devices on Muscle Activation in Squat and Lunge.

CONTEXT: Squats and lunges are common exercises frequently applied in muscle-strengthening and therapeutic exercises. The loading devices are often used to increase the training intensity. OBJECTIVE: To determine the effect of loading devices on muscle activation in squat and lunge and to compare the differences in muscle activation between squat and lunge. DESIGN: Cross-sectional cohort. PARTICIPANTS: Nineteen healthy, male, recreationally active individuals without a history of lower limb injury. INTERVENTIONS: Each participant performed 10 repetitions of a squat under 5 conditions: unloaded, barbell, dumbbell, loaded vest, and kettlebell, and 10 repetitions of a lunge under 4 conditions: unloaded, barbell, dumbbell, and loaded vest. MAIN OUTCOME MEASURES: The electromyography signals of quadriceps, hamstrings, tibialis anterior, gastrocnemius lateralis and medialis were measured. One-way repeated-measure analysis of variance was used to compare the difference among different loading conditions. Paired t test was used to compare the difference between squat and lunge. RESULTS: The muscle activation in the loaded conditions was significantly higher than that in nonloaded conditions in squat and lunge. Compared with the barbell, dumbbell, and loaded vest conditions, the semitendinosus showed significantly higher activation, and the tibialis anterior showed significantly lower activation in kettlebell condition in squat. No significant difference in muscle activation was found among barbell, dumbbell, and kettlebell conditions in lunge. In addition, quadriceps and hamstring activities were significantly higher in lunge than in squat. CONCLUSIONS: Muscle activation was affected by the loading devices in squat but not affected in lunge. Kettlebell squat could be suggested for targeting in strengthening medial hamstring. Progressive strengthening exercise could be recommended from squat to lunge based on sequential activation level.

Harmine combined with paclitaxel inhibits tumor proliferation and induces apoptosis through down-regulation of cyclooxygenase-2 expression in gastric cancer.

Cyclooxygenase-2 (COX-2) serves an important role in the carcinogenesis and progression of gastric cancer. Harmine (HM) and paclitaxel (PTX) are reported as promising drug candidates for cancer therapy, but whether a synergistic anti-tumor effect of HM combined with PTX exists in human gastric cancer remains unknown. The present study evaluated the effects of HM and/or PTX on cell proliferation and apoptosis in a gastric cancer cell line, SGC-7901. HM and PTX inhibited cell proliferation in a dose-dependent manner. Both HM and PTX alone induced apoptosis in gastric cancer cells. The combination of HM and PTX exerted synergistic effects on proliferation inhibition and apoptosis induction in SGC-7901 cells, with down-regulation of COX-2, PCNA and Bcl-2 and up-regulation of Bax expression. The results indicated that combination chemotherapy using HM with PTX exerts an anti-tumor effect for treating gastric cancer. The combination of the two drugs inhibits gastric cancer development more effectively than each drug alone through down-regulation of COX-2 expression.

Strategies for obstacle crossing in older adults with high and low risk of falling.

[Purpose] Tripping is a frequent cause of falls among aging adults. Appropriate limb movements while negotiating obstacles are critical to trip avoidance. The aim of our study was to investigate the mechanics of obstacle crossing in older adults at low or high risk of falling. [Subjects and Methods] Twenty community-dwelling adults aged ≥55 years, were evaluated with the Tinetti Balance and Gait scale and classified as being at high or low risk of falling. Between-group comparisons of kinematics were evaluated for obstacle heights of 10%, 20%, and 30% of leg length. [Results] The high-risk group demonstrated greater toe-obstacle clearance of the leading leg. Increasing obstacle height led to increased maximal toe-obstacle clearance, toe-obstacle distance, and shortened swing phase of the leading limb. Adaptation of clearance height was greater for the trailing leg. Individuals at high risk of falling demonstrated less symmetry between the leading and trailing legs and a narrower step width, features that increase the likelihood of tripping. [Conclusion] Kinematic parameters of obstacle clearance, including the symmetry index described in our study, could provide clinicians with a quick screening tool to identify patients at risk of falling and to evaluate outcomes of training programs.

Effect of ankle kinesio taping on vertical jump with run-up and countermovement jump in athletes with ankle functional instability.

[Purpose] Limited research has been performed in spite of biomechanical evaluation of jump landing with kinesio taping. Therefore, the main objective of this study was to evaluate the effect of kinesio taping applied to athletes. In this study, the authors wished to investigate the effect of kinesio taping during a vertical jump with run-up and countermovement jump on ankle functional instability. [Subjects and Methods] Ten male athletes with ankle functional instability (FI) were recruited in this study from a college volleyball team. Each participant was requested to perform two tasks, the countermovement jump and vertical jump with run-up. Infrared high-speed cameras and force plates were used to assess the effect of ankle taping. [Results] The results showed that the peak ground reaction force in the sagittal plane during a vertical jump with run-up slowed down after kinesio taping and that the peak ankle plantar flexion moment in both types of jump also decreased. [Conclusion] In conclusion, this study proved the effect of kinesio taping on ankle functional instability, which was evaluated by measuring the vertical ground reaction force and peak plantar flexion moment. Its finding may allow us to provide some recommendations for athletes and trainers.

Differences of ballet turns (pirouette) performance between experienced and novice ballet dancers.

PURPOSE: This study investigated the different postural control strategies exhibited by experienced and novice dancers in ballet turns (pirouettes). METHOD: Thirteen novice and 13 experienced dancers performed ballet turns with dominant-leg support. The peak push force was measured in the double-leg support phase. The inclination angles of rotation axis with respect to vertical axis were calculated in the early single-leg support phase as well as the initiation sequence of ankle, knee, and hip joints on the supporting leg. Moreover, the anchoring index of the head was computed in the transverse plane during turning. RESULTS: The novice dancers applied a greater push force, an increased inclination angle of rotation axis, and an insufficient proximal-to-distal extension sequence pattern. The novice dancers also had a smaller head-anchoring index compared with experienced dancers, which meant novice dancers were not using a space target as a stability reference. CONCLUSIONS: A poorer performance in novice dancers could result from higher push force in propulsion, lack of a "proximal-to-distal extension sequence" pattern, and lack of visual spotting for postural stability. Training on sequential initiation of lower-extremity joints and rehearsal of visual spotting are essential for novice dancers to obtain better performance on ballet turns.

Effects of the type and direction of support surface perturbation on postural responses.

BACKGROUND: Postural control is organized around a task goal. The two most frequently used types of tasks for postural control research are translational (translation along the anterior-posterior axis) and rotational (rotation in sagittal plane) surface perturbations. These types of perturbations rotate the ankle joint, causing different magnitudes and directions of body sway. The purpose of this study was to investigate the effects of the type (translation vs. rotation) and direction (forward/toe up vs. backward/toe down) of the perturbation on postural responses. METHOD: Nineteen healthy subjects were tested with four perturbations, i.e., forward and backward translation and toe up and toe down rotation. The onset latency and magnitude of muscle activations, angular changes, and COM displacements were measured. In addition, the kinematic data were divided into two phases. The initial phase reflected the balance disturbance induced by the platform movement, and the reversal phase reflected the balance reaction. RESULTS: The results showed that, in the initial phase, rotational perturbation induced earlier ankle movement and faster and larger vertical COM displacement, while translational and forward/toe up perturbations induced larger head and trunk angular change and faster and larger horizontal COM displacement. In the reversal phase, balance reaction was attained by multi-joint movements. Translational and forward/toe up perturbations that induced larger upper body instability evoked faster muscle activation as well as faster and larger hip or knee joint movements. CONCLUSIONS: These findings provide insights into an appropriate support surface perturbation for the evaluation and training of balance.

Correlations of ß-catenin, Ki67 and Her-2/neu with gastric cancer.

OBJECTIVE: To study the clinical pathologic characteristics of ß-catenin, Ki67 and Her-2/neu in gastric cancer and the correlation of ß-catenin and Ki67 to the protein expression and gene conditions of Her-2/Neu. METHODS: The protein expression of ß-catenin, Ki67 and Her-2/Neu was detected by immunohistochemistry in 101 cases of gastric cancer and the gene conditions of Her-2/Neu by fluorescence in situ hybridization (FISH). RESULTS: The protein expression of ß-catenin, Ki67 and Her-2/Neu had close relationship with the clinical pathologic characteristics of gastric cancer. The ß-catenin and Ki67 had obvious correlation to the differentiation, infiltration and lymphatic metastasis of the gastric cancer (P<0.05). The Ki67 had close relationship with the tumor-node-metastasis staging staging of gastric cancer (P<0.05). Her-2/Neu had close relationship with the differentiation and tumor-node-metastasis staging of gastric cancer (P<0.05) but had no relationship with the infiltration and lymphatic metastasis of the gastric cancer (P<0.05). The protein expression of Ki67 had significantly positive correlation to the protein expression and gene amplification conditions of Her-2/Neu (r=0.567, P<0.05 for protein; r=0.304, P<0.05 for gene). CONCLUSIONS: Combined detection of ß-catenin, Ki67 and Her-2/Neu can be used as a reliable method to help the observation of biological behavior, diagnosis and prognosis of gastric cancer, and Ki67 can be used to serve the preliminary screening of Her-2/Neu gene state.

Effects of leg dominance on performance of ballet turns (pirouettes) by experienced and novice dancers.

Turns (pirouettes) are an important movement in ballet and may be affected by "lateral bias". This study investigated physiological differences exhibited by experienced and novice dancers, respectively, when performing pirouette with dominant and non-dominant leg supports, respectively. Thirteen novice and 13 experienced dancers performed turns on dominant or non-dominant legs. The maximum ankle plantarflexion, knee extension and hip extension were measured during the single-leg support phase. The inclination angle of rotation axis is the angle between instantaneous rotation axis and global vertical axis in the early single-leg support phase. Both groups exhibited a greater hip extension, knee extension, and ankle plantarflexion when performing a turn on the non-dominant leg. For experienced dancers, the inclination angle of rotation axis during the pre-swing phase was generally smaller for dominant leg support than non-dominant leg. However, no significant difference was found in inclination angle of rotation axis of novice dancers. For experienced dancers, an improved performance is obtained when using the dominant leg for support. By contrast, for novice dancers, the performance is independent of choice of support leg. The significant lateral bias in experienced dancers indicates the possible influence of training. That is, repetitive rehearsal on the preferred leg strengthens the impact of side dominance in experienced dancers.

Postural responses to yaw rotation of support surface.

The purposes of this study were to investigate EMG and kinematic responses to yaw rotation of a support surface. Twenty people participated in four conditions, i.e., two velocities (240°/s, 120°/s) and two amplitudes (30°, 15°). Longer latency and smaller muscle responses were induced for yaw rotation, and distal ankle and knee muscles were activated earlier than trunk and neck muscles. Joint kinematics demonstrated larger angular displacements in axial rotation. Velocity and amplitude did not affect onset latency or magnitude of muscle activation but had significant effects on joint movements and COM displacements. Preliminary information about normative data of healthy subjects was obtained, and questions were generated about optimal velocity and amplitude test protocols that require further investigation.

Outcomes of arthroscopic double-bundle PCL reconstruction using the LARS artificial ligament.

The purpose of this study was to assess the outcomes of posterior cruciate ligament (PCL) reconstruction using the Ligament Augmentation and Reconstruction System (LARS) (JK Orthomedic Ltd, Dollard-des-Ormeaux, Quebec, Canada) artificial ligament. Compared with older artificial ligaments, the LARS, which has been used in Europe for 15 years, is more resistant to wear and tear, has satisfactory torsional fatigue resistance, and has good biocompatibility. The current is study included 38 double-bundle PCL reconstructions using the LARS artificial ligament in 38 patients. Mean patient age was 32.6 years, and mean time from injury to surgery was 6 months. Mean follow-up was 37 months (range, 30-68 months). The study endpoint was 2-year follow-up. Mean Tegner score improved from 3.4 ± 0.6 preoperatively to 6.0 ± 1.4 postoperatively (P<.001), and mean Lysholm score improved from 70.0 ± 11.0 pre-operatively to 91.7 ± 5.5 postoperatively (P<.001). Knee laxity decreased significantly postoperatively (P<.001), and no differences existed at 1- and 2-year follow-up. After surgery using the Y-type LARS artificial ligament, knee function and stability improved. Using the LARS artificial ligament for double-bundle reconstruction of the PCL avoids donor-site morbidity and disease transmission. The complication rate is low, and the results appear to be stable with time and comparable with those obtained with other grafts. Double-bundle PCL reconstruction with the LARS artificial ligament may be an alternative treatment option.

Changes in biomechanics and muscle activation in injured ballet dancers during a jump-land task with turnout (Sissonne Fermée).

Large impact loading with abnormal muscle activity and motion patterns may contribute to lower extremity injuries in ballet dancers. Yet, few studies investigated the influence of injury on the ballet movement. The purpose of this study was to find the neuromuscular and biomechanical characteristics in dancers with and without ankle injury during a jump-landing Sissonne Fermée task. Twenty-two ballet dancers were recruited and divided into the injured group (n = 11) and the uninjured group (n = 11). They performed a ballet movement called "Sissonne Fermée" with reflective markers and electrodes attached to their lower extremities. Ground reaction force, joint kinematics, and muscle activity were measured. The injured dancers had greater peak ankle eversion but smaller hindfoot-to-tibial eversion angles. Also, the injured dancers had greater activity of the hamstring of the dominant leg and tibialis anterior of the non-dominant leg during the pre-landing phase. The injured dancers had greater tibialis anterior activity of the dominant leg but less muscle activity in the medial gastrocnemius of the non-dominant leg during the post-landing phase. The injured dancers had a greater co-contraction index in the non-dominant ankle and a lower loading rate. The higher co-contraction indices showed that the injured dancers required more muscle effort to control ankle stability. Furthermore, the injured dancers used a "load avoidance strategy" to protect themselves from re-injury. Neuromuscular control training of the ankle joint for ballet dancers to prevent injury is necessary.

[Effects of 89SrCl2 treatment on CD4+ CD25+ regulatory T cells and its Foxp3 mRNA expression in cancer patients with bone metastases].

OBJECTIVE: To study the influence of 89SrCl2 on CD4+ CD25+ regulatory T cells and its Foxp3 mRNA expression in cancer patients with bone metastases. METHODS: Peripheral blood samples were collected from 57 patients with bone metastases cancer and 25 healthy controls, the amount of CD4+ CD25+ regulatory T cells in peripheral blood was determined by flow cytometry, the expression level of Foxp3 mRNA in these regulatory T cells was detected by RT-PCR. RESULTS: The percentage of CD4+ CD25+ regulatory T cells in CD4+ cells was (11.3 +/- 5.5) % in the patients with bone metastases, which was significantly more than that (5.6 +/- 1.5)% in healthy control (P < 0.01). After the treatment of 89SrCl2, it was decreased to (10.4 +/- 5.2)%, and the decrease was statistically significant (P < 0.05). The expression level of Foxp3 mRNA was decreased significantly from 0.348 +/- 0.028 to 0.296 +/- 0.029 by the treatment of 89SrCl2 (P < 0.05). In addition, the amount of CD4+ CD25+ T cells in the patients obtaining 89SrCl2 therapeutic effects was (9.3 +/- 4.2) %, which was lower than that in those patients without effects (12.9 +/- 5.3)% (P < 0.01). The relative expression level of Foxp3 mRNA was 0.254 +/- 0.025 in the patients obtaining therapeutic effects, which was also significantly less than that (0.397 +/- 0.029) in those patients without any effects (P < 0.01). CONCLUSION: Foxp3 gene play a pivotal role in the regulation of CD4+ CD25+ T cells. The treatment of 89SrCl2 could decrease the amount of CD4+ CD25+ T cells and down-regulate Foxp3 mRNA expression of these cells in bone metastases cancer patients.

Comparison of postural stability between injured and uninjured ballet dancers.

BACKGROUND: Ballet movements require a limited base of support; thus, ballet dancers require a high level of postural control. However, postural stability in ballet dancers is still unclear and needs to be understood. PURPOSE: To evaluate ballet dancers' postural stability in performing single-leg standing, the en pointe task, and the first and fifth positions and to determine differences in task performance among healthy nondancers, healthy dancers, and dancers with ankle sprains. STUDY DESIGN: Controlled laboratory study. METHODS: Injured dancers, uninjured dancers, and nondancers were recruited for this study (N = 33 age-matched participants; n= 11 per group). The tasks tested were single-leg standing with eyes open and closed, first position, fifth position, and en pointe. Center of pressure parameters were calculated from the ground-reaction force collected with 1 force plate. Analysis of variance was used to assess the differences of center of pressure parameters among 3 groups in single-leg standing; independent t test was used to examine the differences of center of pressure parameters between injured and uninjured dancers. RESULTS: During single-leg standing, injured dancers had significantly greater maximum displacement in the medial-lateral direction and total trajectory of center of pressure, compared with the uninjured dancers and nondancers. During the first and fifth positions, the injured dancers demonstrated significantly greater standard deviation of center of pressure position in the medial-lateral and anterior-posterior directions, compared with the uninjured dancers. During en pointe, the injured dancers had significantly greater maximum displacement in the medial-lateral direction and the anterior-posterior direction, compared with the uninjured dancers. CONCLUSION: The injured and uninjured dancers demonstrated differences in postural stability in the medial-lateral direction during single-leg standing and the ballet postures. Although the injured dancers received ballet training, their postural stability may still be inferior to that of the nondancers. CLINICAL RELEVANCE: This study is a first step in understanding that injured ballet dancers do not have the same postural stability as uninjured dancers and that it is even inferior to that of nondancers, which is important to understand for further study on rehabilitation. The future development of effective balance training programs for ballet dancers with ankle injuries should emphasize improvements in medial-lateral directional balance.

Ankle biomechanics of ballet dancers in relevé en pointé dance.

The objective of this study was to study the ankle biomechanics in relevé en pointé of ballet dancers and to investigate the symmetry between dominant and nondominant sides. A three-dimensional motion analysis system and two force platforms were used to collect segmental motion and ground reaction force data during relevé en pointé dancing. Thirteen ballet dancers, each of whom had over 5 years' dance experience (11.37 +/- 3.9 years), were recruited for this study. The results showed that ankle movement patterns were highly correlated (ICC = 0.99) in bilateral comparisons, but only moderate correlation was found in ankle joint moment patterns (ICC = 0.66). The nonldominant ankle showed the same excursion patterns, but different joint moments, when compared to the dominant ankle in relevé en pointé. The indication was that the two ankle joints may play different roles in controlling balance and movements throughout the entire period of the dance movements. Ankle bionmechanical patterns of the fiundamental ballet dance movement, relevé en pointé, also were constructed in this study to help interpret and understand the bilateral ankle joint excursion pattern.

Muscle forces analysis in the shoulder mechanism during wheelchair propulsion.

This study combines an ergometric wheelchair, a six-camera video motion capture system and a prototype computer graphics based musculoskeletal model (CGMM) to predict shoulder joint loading, muscle contraction force per muscle and the sequence of muscular actions during wheelchair propulsion, and also to provide an animated computer graphics model of the relative interactions. Five healthy male subjects with no history of upper extremity injury participated. A conventional manual wheelchair was equipped with a six-component load cell to collect three-dimensional forces and moments experienced by the wheel, allowing real-time measurement of hand/rim force applied by subjects during normal wheelchair operation. An ExpertVision six-camera video motion capture system collected trajectory data of markers attached on anatomical positions. The CGMM was used to simulate and animate muscle action by using an optimization technique combining observed muscular motions with physiological constraints to estimate muscle contraction forces during wheelchair propulsion. The CGMM provides results that satisfactorily match the predictions of previous work, disregarding minor differences which presumably result from differing experimental conditions, measurement technologies and subjects. Specifically, the CGMM shows that the supraspinatus, infraspinatus, anterior deltoid, pectoralis major and biceps long head are the prime movers during the propulsion phase. The middle and posterior deltoid and supraspinatus muscles are responsible for arm return during the recovery phase. CGMM modelling shows that the rotator cuff and pectoralis major play an important role during wheelchair propulsion, confirming the known risk of injury for these muscles during wheelchair propulsion. The CGMM successfully transforms six-camera video motion capture data into a technically useful and visually interesting animated video model of the shoulder musculoskeletal system. The CGMM further yields accurate estimates of muscular forces during motion, indicating that this prototype modelling and analysis technique will aid in study, analysis and therapy of the mechanics and underlying pathomechanics involved in various musculoskeletal overuse syndromes.

Mechanical energy and power flow of the upper extremity in manual wheelchair propulsion.

OBJECTIVE: To investigate the characteristics of mechanical energy and power flow of the upper limb during wheelchair propulsion. DESIGN: Mechanical energy and power flow of segments were calculated. BACKGROUND: Very few studies have taken into account the mechanical energy and power flow of the musculoskeletal system during wheelchair propulsion. Mechanical energy and power flow have proven to be useful tools for investigating locomotion disorders during human gait. METHODS: Twelve healthy male adults (mean age, 23.5 years) were recruited for this study. Three-dimensional kinematic and kinetic data of the upper extremity were collected during wheelchair propulsion using a Hi-Res Expert Vision system and an instrumented wheel, respectively. RESULTS: During the initiation of the propulsion phase, joint power is generated in the upper arm or is transferred from the trunk downward to the forearm and hand to propel the wheel forward. During terminal propulsion, joint power is transferred upward to the trunk from the forearm and upper arm. The rate of change of mechanical energy and power flow for the forearm and hand have similar patterns, but the upper arm values differ. CONCLUSIONS: Joint power plays an important role in energy transfer as well as the energy generated and absorbed by muscles spanning the joints during wheelchair propulsion. RELEVANCE: Energy and power flow information during wheelchair propulsion allows us to gain a better understanding of the coordination of the movement by the musculoskeletal system.