Shoulder Joint Flexion Research Articles

Variability in musculoskeletal fatigue responses associated with repeated exposure to an occupational overhead drilling task completed on successive days

Emerging research suggests that muscular and kinematic responses to overhead work display a high degree of variability in fatigue-related muscular and kinematics changes, both between and within individuals when evaluated across separate days. This study examined whether electromyographic (EMG), kinematic, and kinetic responses to an overhead drilling task performed until volitional fatigue were comparable to those of a repeated identical exposure of the task completed 1 week later. Surface EMG and intramuscular EMG, sampled from 7 shoulder muscles, and right upper limb kinematics and kinetics were analyzed from 15 male and 14 female participants. No significant day-to-day changes in EMG mean power frequency (MPF) were observed, though serratus anterior displayed significantly less fatigue-related increase in EMG root-mean-squared (RMS) signal amplitude on day 2. Unfatigued upper kinematics on day 2 featured an increase in thoracohumeral elevation, elbow flexion, and decrease in wrist ulnar deviation compared to unfatigued state on day 1. Fatigue-related changes in shoulder joint flexion moment that were present on day 1 were reduced on day 2, suggesting that a more efficient overhead work strategy was learned and preserved across successive days. Day-to-day changes in upper limb joint angle variability, quantified by median absolute deviation (MdAD), were joint dependent. Despite yielding a variable fatigue-related kinetic strategy on both days, kinematic and kinetic fatigue-related changes on a second day of completing an overhead drilling task suggested a potential kinematic learning effect.

Comparative analysis of biomechanical characteristics between the new Tai Chi elastic band exercise for opening and closing movement and elastic band resistance training for the reverse fly movement.

The objective of this study was to compare and analyze the representative opening and closing movement of Tai Chi elastic band exercise with the reverse fly movement of elastic band resistance training. The aim was to explore the biomechanical differences between the two exercises and provide theoretical support for the application of Tai Chi elastic band exercise in health intervention. A total of 26 male participants were recruited and randomly divided into two groups in a 1:1 ratio. There were 13 participants in each Tai Chi elastic band exercise group and elastic band resistance training group. Both groups of participants used an elastic band to perform movement in the experiment. Experimental data were collected using the Vicon infrared motion capture system and Delsys surface EMG system. The AnyBody software was utilized to simulate the creation of a musculoskeletal model for both exercises. The study found that the Tai Chi elastic band exercise group exhibited smaller horizontal abduction angle and flexion angle of the shoulder joint, as well as normalized RMS of the anterior deltoid and triceps brachii, compared to the elastic band resistance training group (P < 0.01); the Tai Chi elastic band exercise group exhibited greater elbow flexion angle, elbow flexion torque, and muscle strength of the infraspinatus, coracobrachialis, biceps brachii, brachialis and brachioradialis, compared to the elastic band resistance training group (P < 0.01); the Tai Chi elastic band exercise group exhibited smaller horizontal abduction angular velocity of the shoulder joint and a lower normalized RMS of the posterior deltoid, compared to the elastic band resistance training group (P < 0.05). (1) The opening and closing movement of Tai Chi elastic band exercise is characterized by a large elbow flexion angle, a small shoulder joint horizontal angle and flexion angle, and a slow and uniform speed of movement. The reverse fly movement of elastic band resistance training is characterized by a large horizontal abduction angle of the shoulder joint, a large flexion angle of the shoulder joint, a small flexion angle of the elbow joint, and a fast and uneven speed. (2) The opening and closing movement exerts a greater torque on the elbow flexion, while the reverse fly movement exerts a greater torque on the shoulder joint horizontal abduction and external rotation. (3) The opening and closing movement provide greater stimulation to the infraspinatus, coracobrachialis, and elbow flexor, while the reverse fly movement provides greater stimulation to the posterior deltoid, anterior deltoid, subscapularis, and elbow extensor. In summary, the variation in joint angle, joint angular velocity, and hand position could be the factor contributing to the differences in joint torque and muscle activity between the opening and closing movement of Tai Chi elastic band exercise and the reverse fly movement of elastic band resistance training.

Effects of Sling-Suspension-Based Active Shoulder Joint Exercise on Shoulder Joint Subluxation, Pain, Muscle Strength, and Upper Limb Function in Patients with Subacute Stroke.

Background and Objectives: We investigated the effects of sling-suspension-based active shoulder joint exercise training on shoulder joint subluxation, pain, muscle strength, and upper extremity function in patients with subacute stroke. Materials and Methods: Twenty-eight patients with subacute stroke were randomly assigned to either the sling-suspension-based active shoulder joint exercise (SASE) group (n = 14) or the motorized upper extremity exercise (MUEE) group (n = 14). The SASE group actively performed shoulder joint flexion, extension, abduction, adduction, external and internal rotation, and horizontal abduction and adduction using a sling suspension system, whereas the MUEE group underwent an exercise program using a motorized upper extremity exercise machine. All participants underwent a 4-week intervention with 30 min of exercise once a day for 5 days a week. Additionally, both groups received general physical therapy and functional electrical stimulation for 30 min twice a day for 5 days a week. Shoulder joint subluxation was measured by radiographic examination before and after training, and pain was evaluated in the splenius, upper trapezius, and infraspinatus muscles using pressure parameters. In addition, a manual muscle tester was used to assess the muscle strength of the shoulder joint flexors, extensors, abductors, adductors, and external and internal rotators, and the Fugl-Mayer Assessment (FMA) and Manual Functional Test (MFT) were used to evaluate upper extremity function. Results: A significant group-time interaction was observed for pain, with F-values of F(1, 26) = 7.470, p < 0.011 for the splenius and F(1, 26) = 9.623, p < 0.005 for the upper trapezius. A significant time-group interaction was observed for the muscle strength of the shoulder, with F-values of F(1, 26) = 13.211, p < 0.001; F(1, 26) = 4.974, p = 0.035 and F(1, 26) = 9.674, p = 0.004 for flexors, abductors, and external rotators, respectively. A significant time-group interaction was observed in the FMA, with F-values of F(1, 26) = 13.243, p < 0.001. When comparing the interaction effects between time and group for MFT scores, a significant difference was observed, with F-values of F(1, 26) = 32.386, p < 0.001. Conclusions: This study confirmed that sling-suspension-based active shoulder joint exercises are effective in improving shoulder joint subluxation, pain, muscle strength, and upper extremity function in patients with subacute stroke.

Effects of Upper Limb Control on the Less-Affected Side on Upper Limb Function, Respiration, Balance, and Activities of Daily Living in Stroke.

Background and Objectives: This study aimed to investigate the effects of upper limb control exercises on upper limb function, respiration, balance, and activities of daily living in patients with stroke. Materials and Methods: The 28 patients who met the selection criteria were randomly assigned to two groups of 14 patients each. Subsequently, upper limb control exercises using real-time feedback were applied. The same interventional exercise was applied to both the less-affected and affected limbs of the study participants, who were classified into a less-affected side upper limb control group and an affected side upper limb control exercise group. Interventional exercises, 30 min each, were performed five times weekly for 4 weeks, and follow-up examinations were performed 2 weeks after the end of exercise. Electronic muscle strength measurements and an electronic goniometer were used to evaluate upper limb function. A spirometer was used to measure respiration. Balance ability was evaluated using a force plate pressure distribution measuring system with a sensor that detects the movement of the body center on the ground. Daily life movements were evaluated using the Korean version of the modified Barthel index. Results: When examining the results, the upper limb function on the paralyzed side showed an increase in the electromyographic strength of shoulder joint depression and flexion angle. Improvements were also observed in respiration (forced vital capacity [L] and forced expiratory volume in 1 s [L]), balance (95% confidence ellipse area [mm2] and center of pressure displacement [mm]), and daily life activities, all of which showed statistically significant differences in the time × group interaction effect (p < 0.05). Conclusions: Thus, it was found that the upper limb control exercise on the less-affected side had a significant effect when the exercise was performed together with treatment on the affected side in patients with stroke. It is anticipated that this study will provide basic data for evaluating both the trunk and upper limbs of the less-affected and affected sides.

Feature analysis of joint motion in paralyzed and non-paralyzed upper limbs while reaching the occiput: A cross-sectional study in patients with mild hemiplegia.

The reaching motion to the back of the head with the hand is an important movement for daily living. The scores of upper limb function tests used in clinical practice alone are difficult to use as a reference when planning exercises for movement improvements. This cross-sectional study aimed to clarify in patients with mild hemiplegia the kinematic characteristics of paralyzed and non-paralyzed upper limbs reaching the occiput. Ten patients with post-stroke hemiplegia who attended the Department of Rehabilitation Medicine of the Jikei University Hospital and met the eligibility criteria were included. Reaching motion to the back of the head by the participants' paralyzed and non-paralyzed upper limbs was measured using three-dimensional motion analysis, and the motor time, joint angles, and angular velocities were calculated. Repeated measures multivariate analysis of covariance was performed on these data. After confirming the fit to the binomial logistic regression model, the cutoff values were calculated using receiver operating characteristic curves. Pattern identification using random forest clustering was performed to analyze the pattern of motor time and joint angles. The cutoff values for the movement until the hand reached the back of the head were 1.6 s for the motor time, 55° for the maximum shoulder joint flexion angle, and 145° for the maximum elbow joint flexion angle. The cutoff values for the movement from the back of the head to the hand being returned to its original position were 1.6 s for the motor time, 145° for the maximum elbow joint flexion angle, 53°/s for the maximum angular velocity of shoulder joint abduction, and 62°/s for the maximum angular velocity of elbow joint flexion. The numbers of clusters were three, four, and four for the outward non-paralyzed side, outward and return paralyzed side, and return non-paralyzed side, respectively. The findings obtained by this study can be used for practice planning in patients with mild hemiplegia who aim to improve the reaching motion to the occiput.

Double-pulley, V-shaped fixation technique for arthroscopic repair of ideberg type IA glenoid fracture.

Different techniques have been described for glenoid fractures, there is still a need for safe and effective agents to promote outcomes. From January 2016 to April 2021, the clinical data of 17 patients with pulley type IA fractures treated by the V-shaped fixation technique under shoulder arthroscopy were retrospectively analyzed. Preoperative X-ray, CT, and MRI examinations were completed. The functional score of the shoulder joint, such as the visual analog scale (VAS), Constant score, and Modified Rowe score, was used to evaluate the preoperative and final follow-up clinical outcomes. The active shoulder range of motion (ROM) was also collected preoperatively and at the final postoperative follow-up. Accordingly, intraoperative and postoperative complications were also observed. The mean follow-up was 49.52 months (16-79months). The patients' follow-up exams showed that shoulder joint flexion, abduction, external rotation, internal rotation, and pain were not significantly different from those of the contralateral side (p > .05). The mean Constant score was 83.52 (58-98), and the average Modified Rowe score was 94.29 (70-100). X-ray and CT films of all cases showed good healing without articular depression or steps. Three patients had traumatic arthritis, with VAS <3 pain. No postoperative complications, such as infections, nerve or vessel damage, or suture anchor problems occurred during the follow-up period. Using the Double-pull, V-shaped fixation technique can stabilize the reduction of glenoid fractures while reducing the possibility of bone destruction. It is a good solution and provides an opportunity to treat rotator cuff tears associated with the procedure.

Efficiency of the use of coordination training in the program of medical rehabilitation of patients after reverse shoulder endoprosthesis

The goal of this study. The goal is to evaluate the effectiveness of using upper limb coordination training after reverse shoulder arthroplasty.Material and methods. 30 patients were examined in Federal State Budgetary Institution «National Medical Research Center for Rehabilitation and Balneology» of the Ministry of Health of the Russian Federation. They were examined in a long-term period after reverse shoulder arthroplasty (in 3–4 months) and were divided into two groups: the main and the comparison groups. All patients were similar in terms of gender and age. Their clinical and functional parameters of the shoulder joint were also comparable. The patients in the comparison group were treated with laser therapy, electrotherapy, massage, group exercises to train the upper limb and mechanotherapy. The patients in the main group additionally underwent coordination training with biological feedback to the shoulder joint.The results of the study were evaluated according to the pain syndrome, functional activity of the shoulder joint, shoulder joint flexion angle and values of dynamic strength of the shoulder muscles. After the course of medical rehabilitation, the patients in both groups showed improvement of all clinical and functional parameters of the shoulder joint. There was a statistically significant improvement in the dynamic strength of the shoulder joint and reduction of pain syndrome in the patients in the main group.Conclusions. The inclusion of shoulder coordination training allows to improve the rehabilitation results for the patients who undergo reverse shoulder joint arthroplasty.

Exercises with the StretchPole improve shoulder joint range of motion

The ‘StretchPole’ foam roller product is mainly used to loosen muscle groups and joints in the deeper layers of the body that are normally inaccessible to the human hand, and to realign the skeletal structure by lying on the pole and performing exercises. It is also used to strengthen the core, which plays an important role in postural maintenance and stability. The purpose of this study was to determine the effects of the ‘Solacon’ exercise routine using a StretchPole on shoulder joint range of motion. Forty healthy participants performed Solacon exercises using a StretchPole. The specific method of Solacon comprises six movements: (1) chest slide, (2) crescent, (3) cone, (4) twister, (5) shoulder alternating rotation, and (6) chin-in exercise. The joint range of motion of the bilateral shoulder joint flexion, abduction, horizontal abduction, and external rotation (1st and 2nd) were measured before and after the exercises. All measures were significantly higher after exercise compared to before exercise. Solacon exercises improve thoracic spine and scapular mobility and stretch the anterior thoracic muscle groups. The shoulder joint in the broad sense consists of the humerus, scapula, clavicle, sternum, and ribs. These in turn constitute the scapulohumeral joint, acromioclavicular joint, sternoclavicular joint, scapulothoracic joint and functional second shoulder joint. In addition, costovertebral joints and intervertebral joints are also involved because of the added motion of the ribs and the spine. We considered that the ranges of motion of shoulder joint flexion, abduction, horizontal abduction, and external rotation measured in this study were expanded.

Pouzdanost i validnost merenja fleksije ramenog zgloba digitalnom i standardnom goniometrijskom metodom

Based on the literature review and clinical experiences, it can be concluded that measuring the amplitude of movement is one of the fundamental kinesiometric methods used in assessing joint functionality. The aim of this study was to examine the reliability and validity of measuring the shoulder joint's range of motion using the digital system KEMTAI compared to a goniometer with arms. This non-experimental observation was conducted on 40 participants whose flexion range in the shoulder joint was measured using both the goniometer with arms and the KEMTAI software system, which utilizes the examiner's mobile phone camera. The results indicated that the lowest mean value was obtained during the first measurement session (M1 = 154.68), while the highest was during the third session (M2 = 156.53). When using the KEMTAI software, the variability of mean values for the total tested population was significantly higher than when using the goniometer with arms. The results suggest that the KEMTAI software/system is reliable when comparing the average results of three measurements. Based on these findings, it is concluded that three experienced measurers demonstrated high reliability in measuring the shoulder joint's flexion range using the goniometer with arms. Despite the identified differences between the measurement results obtained using these two methods, it is considered that the KEMTAI software/system is applicable in practical work.

Treatment of Ideberg type Ⅱ scapular glenoid fracture with compression screw combined with Buttress plate through direct axillary approach

To investigate the effectiveness of compression screw combined with Buttress plate through direct axillary approach for Ideberg typeⅡ scapular glenoid fractures. A retrospective analysis was conducted on 11 patients with Ideberg type Ⅱ scapular glenoid fractures treated with compression screws combined with Buttress plate fixation through the direct axillary approach between January 2014 and June 2022. There were 7 males and 4 females, aged from 34 to 75 years, with an average of 56.0 years. The causes of injury included 4 cases of falling from height injury, 4 cases of heavy object injury, and 3 cases of traffic accident injury. The time from injury to operation was 2-5 days, with an average of 3.8 days. The operation time, intraoperative blood loss, hospital stay, complications, and fracture healing time were recorded. The Constant-Murley score, American Society of Shoulder and Elbow Surgeons (ASES) score, and shoulder joint flexion, abduction, external rotation (neutral position), and internal rotation (neutral position) range of motion were used to evaluate shoulder joint pain and function. The operation time was 45-105 minutes, with an average of 79.0 minutes; the intraoperative blood loss was 80-200 mL, with an average of 99.2 mL; the hospital stay was 3-8 days, with an average of 5.8 days. One patient had poor wound healing after operation, and the wound healed after strengthening dressing change; the rest wounds had primary healing, and no axillary nerve paralysis occurred. Except for 1 patient lost follow-up, the remaining 10 patients were followed up 10-54 months, with an average of 26.4 months. The postoperative X-ray film examination showed that the fractures healed well within 8-15 weeks, with an average of 11.0 weeks. There was no complication such as fracture displacement, internal fixator failure or fracture during follow-up. At last follow-up, the patient's shoulder joint flexion, abduction, external rotation (neutral position), and internal rotation (neutral position) range of motion, Constant-Murley score, and ASES score significantly improved when compared with those before operation ( P<0.05). Compression screw combined with Buttress plate through direct axillary approach is an effective way to treat Ideberg typeⅡ scapular glenoid fracture, with advantages of small trauma, concealed incision, and good effectiveness.

Movement analysis of fully immersive virtual reality therapeutic module for usage in physical therapy field

Objective. To analyze the users’ movement during performing the tasks of Fully Immersive Virtual Reality Therapeutic module. Methods. An observational study was conducted at the Faculty of Physical Therapy, Cairo University, Egypt. Healthy college-aged volunteers participated invited to participate in the study from 1st January 2023 to 25th April 2023. All participants were invited to use the fully immersive VRaputic® software module (Vibilo™). Movement analysis was performed via Kinovea 0.9.5×64 version video analyzing software on different views of photographs of each participant. Results. The arc of motion performed during the module was in the following joints and directions in the upper limb: shoulder joint (flexion (133.58 ± 5.10)), elbow joint (flexion (99.42 ± 5.66), and extension (2.35 ± 1.41)). Conclusions. It was concluded that the selected fully immersive VRaputic® software (Vibilo™), a therapeutic module, could be prescribed for the management of kinesiophobia, shoulder dysfunction, elbow stiffness, low back pain, hip and knee joint dysfunction, and neurological cases (post-stroke, cerebral palsy, Erb’s palsy) based on different joints’ arc of motion performed during the module.

Comparison of the Effects of Two Different Stretching on Shoulder Flexion Angle, Muscle Tone, and Thoracic Mobility in Subjects with Short Latissimus Dorsi Muscle

This study aimed to compare the effects of two latissimus dorsi muscle (LD) stretching exercises on the shoulder joint flexion angle, LD muscle tone, and thoracic mobility in subjects with short LD. This was a cross-sectional and randomized controlled trial. The study included 28 subjects with a short LD. Participants showing a range of shoulder flexion of <170° in the LD length test were identified as having a short LD. The subjects were randomly assigned to either Group 1 (shoulder abduction + contralateral trunk side bending) or Group 2 (shoulder abduction + shoulder external rotation). LD muscle tone and stiffness were measured using Myoton PRO. Thoracic mobility of the middle part was measured using a circular tape measure. Both groups 1 and 2 showed significantly increased range of shoulder flexion and middle thoracic mobility, and the LD muscle tone of the distal and lower parts and LD muscle stiffness of the distal parts decreased significantly after interventions (p<.05). In the comparison between groups, no significant differences were noted in all dependent variables. Therefore, this study suggests that both LD stretching exercises can be effective in increasing the range of shoulder flexion, reducing LD muscle tone and stiffness, and improving chest mobility.

The reliability and validity of joint range of motion measurement using zoom and a smartphone application.

[Purpose] This study aimed to evaluate the reliability and validity of measuring the range of motion of joints using a remote videoconferencing system (Zoom) and a smartphone application. [Participants and Methods] This study included 16 young and healthy adults. The participants were instructed to perform shoulder joint flexion exercises in a seated position, with automatic motions, and maintain that posture throughout the measurement. Two measurements were performed: 1) angle measurement using a three-dimensional (3D) motion analyzer, and 2) angle measurement using the videoconference software, Zoom, and a smartphone application. Intra- and inter-rater reliabilities were calculated using the intraclass correlation coefficients (ICC). The degree of agreement between the representative values of each measurer and the 3D motion analyzer was examined. [Results] ICC (1, 1) for intra-examiner reliability were 0.912 and 0.996. For the inter-rater reliability, the ICC (2, 1) was 0.945. The correlation coefficient between each examiner's value and the value of the 3D motion analyzer was 0.955 and 0.980, respectively. The Bland-Altman analysis results indicated no systematic error. [Conclusion] The method of remotely measuring joint range of motion using Zoom and a smartphone application demonstrated high reliability and validity.

Takım Sporcularında Üst Ekstremite Propriosepsiyonlarının Karşılaştırılması

Shoulder strength flexibility and proprioception are of great importance for athletes who do overhead activities and throwing sports. In volleyball, basketball, and handball, the shoulder muscles work under heavy conditions under the technical load of the game. In this study, it was aimed to compare the shoulder force senses (FS) of team athletes. A total of 36 healthy individuals, including 14 volleyball, 12 basketball, and 10 handball players, with a mean age of 19.0 ± 2.6833, participated in the study. First, the maximal isometric voluntary contraction (MVIC) levels of the participants were measured during shoulder joint flexion, then the 50% MVIC target force value was determined, and a two-trial FS test was performed with this value. The target force value was evaluated by visual feedback from the computer screen. In the data analysis, independent t-tests and ANOVA tests were applied in the SPSS 28.0 for Mac package program. When the results of the research were examined, no statistical significance was found between the measurements of Trial1 and Trial2 in terms of gender. However, when the FS averages are examined, it has been determined that women have a better sense of force than men. It was determined that the median of the MVIC values was 70.35 and the participants were divided into two groups as lower and upper. A statistically significant difference was found between the determined MVIC groups and age, training age, gender, branch, and BMI. No statistically significant difference was found between the MVIC groups and the distance of the sense to the target. The difference in values can be explained by the fact that individuals with low MVIC have a better sense of force than individuals with high MVIC.

Relationship Between Shoulder Pain and Joint Reaction Forces and Muscle Moments During 2 Speeds of Wheelchair Propulsion.

The purpose of this study was to determine shoulder joint reaction forces and muscle moments during 2 speeds (1.3 and 2.2m/s) of wheelchair propulsion and to investigate the relationship between joints reaction forces, muscle moments, and shoulder pain. The measurements were obtained from 20 manual wheelchair users. A JR3 6-channel load sensor (±1% error) and a Qualisys system were used to record 3-dimensional pushrim kinetics and kinematics. A 3-dimensional inverse dynamic model was generated to compute joint kinetics. The results demonstrated significant differences in shoulder joint forces and moments (P < .01) between the 2 speeds of wheelchair propulsion. The greatest peak shoulder joint forces during the drive phase were anterior directed (Fy, 184.69N), and the greatest joint moment was the shoulder flexion direction (flexion moment, 35.79N·m) at 2.2m/s. All the shoulder joint reaction forces and flexion moment were significantly (P < .05) related to shoulder pain index. The forces combined in superior and anterior direction found at the shoulder joint may contribute to the compression of subacromial structure and predispose manual wheelchair users to potential rotator cuff impingement syndrome.

Physical fitness and frailty status of frail older adults in long-term care facilities after acupunch exercises: A cluster-randomized controlled trial.

Frailty is a complex geriatric syndrome and serves as an indicator for functional degradation in older adults. Regular exercise intervention could reduce the level of frailty and improve general physical fitness. The aim of this study was to test the effects of the Vitality Acupunch (VA) exercise on the promotion of physical fitness and the improvement of frailty status among frail older adults in long-term care facilities. This study was a cluster-randomized controlled trial adopted a pretest-posttest design. Using convenience sampling, 81 frail adults older than 65years of age from 10 long-term care facilities participated in this study. The older adults were cluster-randomized by facility into an intervention group (5 long-term care facilities, n=40) and a control group (5 long-term care facilities, n=41). The intervention group engaged in the VA exercise 3 times a week, each lasting 40min, for 24weeks. The control group maintained regular activities of daily living. The outcome measures for physical fitness were assessed before study began (pretest), at the 12th week (posttest 1), and at the 24th week (posttest 2) in the study. After a 24-week intervention, the frail older adults who engaged in the VA exercise program showed significant improvements in handgrip strength, upper-limb muscle endurance, lung function, shoulder flexibility, forward flexion, shoulder joint flexion, and shoulder joint abduction (all p<0.05) but not in lower-limb muscle endurance (p=0.502) compared against their pretest data. The intervention group had significantly better physical fitness and positive changes in frailty status than the control group (all p<0.001), except for the lower-limb muscle endurance (p=0.557). Regular engagement in the VA exercise program for 24weeks significantly improved the physical fitness and frailty status of frail older adults in long-term care facilities.

Entry phase in men's backward dive pike: association between the shoulder joint and trunk angles.

A high prevalence of lower back pain has been observed in competitive divers. Hyperextension of the lumbar vertebrae during water entry is considered the main mechanism behind the incidence of lower back pain in divers. Therefore, this study aimed to investigate the influence of the shoulder angle on the entry alignment. Posture angles of 13 male drivers (age: 16.8±2.9 years) who were invited to the national training camp in 2012 by Japan Swimming were recorded at the time of water entry via 201B using a high-speed camera. A negative correlation was observed between shoulder joint flexion and trunk extension angles on water entry. In addition, the trunk angle was significantly different between groups. For the lower back pain group, 210.4±5.7°, and in the non-lower back pain group, 199.9±9.0°, angles were observed with a larger extension of the trunk on water entry in the lower back pain group. The alignment on water entry was associated with the occurrence of lower back pain. Which suggested that enough shoulder flexibility can prevent the incidence of lower back pain.

Effects of arm and leg positions on lumbar multifidus muscle activity while on hands and knees or while standing

BackgroundThe lumbar multifidus (LMF) muscle, which is involved in the mechanical stability of the lumbar spine, reportedly undergoes atrophy in patients with low back pain. Preventing or mitigating low back pain requires strengthening the LMF muscle; however, methods for triggering selective and significant contraction of this muscle have not been fully studied. This study aims to clarify how, in the hands-and-knees or standing position, the position of the arm and leg on one side affects the activity of the lumbar erector spinae (LES) and LMF muscles.MethodsWe recruited nine adult men with no prior history of low back pain. Measurements were taken in four different postures under varying conditions (that is, one arm and one leg were lifted in either the hands-and-knees or standing position,) as follows: (1) shoulder joint flexion and hip joint extension in the hands-and-knees position; (2) 90° shoulder joint abduction and hip joint abduction in the hands-and-knees position; (3) shoulder joint flexion and hip joint extension in the standing position; and (4) 90° shoulder joint abduction and hip joint abduction in the standing position. The 90° shoulder joint abduction involved simultaneous horizontal abduction, while the hip joint abduction involved simultaneous extension. Muscle activity of the LES and LMF in each posture was measured using a surface electromyograph.ResultsMuscle activity of the LMF was significantly higher in 90° shoulder joint abduction and hip joint abduction than in shoulder joint flexion and hip joint extension in both the hands-and-knees and standing positions. The LES muscle showed no significant differences in activity between each posture.ConclusionsThe results suggest that unilateral 90° shoulder joint abduction and contralateral hip joint abduction in the hands-and-knees and standing positions may produce selective and significant contraction of the LMF muscle.

Nanomaterials Combined with Sports Rehabilitation Therapy in the Treatment of Shoulder Arthritis of Volleyball Players

Shoulder arthritis is one of the most common injuries of professional volleyball players. It needs shoulder force to buckle, block, and bounce, which leads to frequent shoulder injuries. In addition, the late rehabilitation treatment is not in place, which will seriously affect the performance of volleyball players’ skills. Periarthritis of the shoulder is referred to as frozen shoulder, commonly known as congealed shoulder and fifty shoulder. The shoulder pain gradually develops, worse at night, and gradually increases, and the shoulder joint movement function is limited and increasingly aggravated. After reaching a certain level, it gradually relieves and finally fully recovers as the main manifestations of the shoulder joint capsule and its surrounding ligaments and tendons. Shoulder periarthritis is a common condition in which shoulder pain and inconvenience are the main symptoms. This paper studies the application of nanomaterials combined with sports rehabilitation therapy in the treatment of shoulder arthritis of volleyball players. We selected 50 volleyball players with shoulder arthritis injuries, randomly assigned nanomaterials combined with sports rehabilitation therapy as the experimental group and traditional sports rehabilitation therapy as the control group, 25 cases in each group. The experimental group was treated with nanomaterials combined with sports rehabilitation, while the control group was treated with traditional sports recovery methods for 5 weeks. Nanomaterials have a certain uniqueness. When the scale of matter is small to a certain extent, quantum mechanics must be used instead of traditional mechanics to describe its behavior. When the particle size of the powder is reduced from 10 microns to 10 nanometers, its particle size is 1000 times, and when converted into volume, it will be 10 times the 9th power, so there will be obvious differences in the behavior of the two. The physical examination of the two groups of volleyball players’ shoulder joint visual analogue scale (VAS) pain score and shoulder joint isokinetic detection (including shoulder joint extension and adduction, shoulder joint flexion and extension, and shoulder joint movement to 90° shape) is compared. The results showed that the VAS score of the experimental group was significantly lower than that of the control group (P &lt; 0.05), and the isokinetic test of the experimental group was better than that of the control group (P &lt; 0.05). After exercise rehabilitation training for shoulder joint dysfunction, the average strength and activation of 10 muscles were improved, among which the lower trapezius, the middle trapezius, and the serratus anterior were significantly improved. It can be seen that as an effective treatment of shoulder arthritis, nanomaterials combined with sports rehabilitation therapy can not only accelerate the rapid recovery of volleyball players after injury but also effectively prevent the occurrence of arthritis symptoms, so that volleyball players can give full play to their skills on the court.

A study of shoulder extensor muscles and vibration conditions suitable for generating the illusion of shoulder joint flexion using vibration stimulation

A study of shoulder extensor muscles and vibration conditions suitable for generating the illusion of shoulder joint flexion using vibration stimulation