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Frontiers in Physiology 2024The use of elastomeric technology in sports garments is increasing in popularity; however, its specific impact on physiological and psychological variables is not fully...
The use of elastomeric technology in sports garments is increasing in popularity; however, its specific impact on physiological and psychological variables is not fully understood. Thus, we aimed to analyze the physiological (muscle activation of the pectoralis major, triceps brachii, anterior deltoid, and rectus abdominis, capillary blood lactate, systolic and diastolic blood pressure, and heart rate) and psychological (global and respiratory rating of perceived exertion [RPE]) responses during an incremental treadmill test wearing a new sports garment for the upper body that incorporates elastomeric technology or a placebo garment. Eighteen physically active young adults participated in two randomized sessions, one wearing the elastomeric garment and the other wearing a placebo. Participants performed in both sessions the same treadmill incremental test (i.e., starting at 8 km/h, an increase of 2 km/h each stage, stage duration of 3 min, and inclination of 1%; the test ended after completing the 18 km/h Stage or participant volitional exhaustion). The dependent variables were assessed before, during, and/or after the test. Nonparametric tests evaluated differences. The elastomeric garment led to a greater muscle activation ( < 0.05) in the pectoralis major at 16 km/h (+33.35%, = 0.01, = 0.47) and 18 km/h (+32.09%, = 0.02, = 0.55) and in the triceps brachii at 10 km/h (+20.28%, = 0.01, = 0.41) and 12 km/h (+34.95%, = 0.04, = 0.28). Additionally, lower lactate was observed at the end of the test (-7.81%, = 0.01, = 0.68) and after 5 min of recovery (-13.71%, < 0.001, = 1.00) with the elastomeric garment. Nonsignificant differences between the garments were encountered in the time to exhaustion, cardiovascular responses, or ratings of perceived exertion. These findings suggest that elastomeric garments enhance physiological responses (muscle activation and blood lactate) during an incremental treadmill test without impairing physical performance or effort perception.
PubMed: 38711952
DOI: 10.3389/fphys.2024.1372020 -
JSES International May 2024The deltoid is a trisegmented muscle with anterior, middle, and posterior components. While the clinical relevance of the presence of anatomic variations of the deltoid...
BACKGROUND
The deltoid is a trisegmented muscle with anterior, middle, and posterior components. While the clinical relevance of the presence of anatomic variations of the deltoid origin and insertion continues to be debated, the architecture of the deltoid muscle is more complex than initially believed. This study aimed to evaluate the gross anatomy of the deltoid muscle insertion by qualitatively and quantitatively characterizing the insertion and location of the deltoid muscle's anterior, middle, and posterior components. This information is valuable to surgeons as it raises awareness of potential variants that could be encountered during surgery, promotes mindfulness of neurovascular proximities, and reduces the likelihood of confusion between adjacent muscle fibers.
METHODS
Eight nonpaired, fresh-frozen clavicle-to-fingertip cadaveric shoulders were acquired for the study (6 left, 2 right). The average age of the cadavers was 79.5 years (range: 64-92). The standard deltopectoral approach was carried out on all specimens. The planes dividing the anterior, middle, and posterior deltoid were identified and marked. Once complete exposure had been achieved, digital calipers were used to record the size of the deltoid insertion. The specimens were qualitatively assessed to characterize the style of insertion they demonstrated.
RESULTS
The average length of the deltoid insertion was 39.45 ± 9.33 mm (n = 8). Six of the eight shoulders demonstrated an insertion style previously characterized in the literature. The remaining two shoulders highlighted an insertion pattern not previously described.
CONCLUSION
The current study demonstrates a novel insertion pattern for the deltoid muscle that has not been previously characterized. This "step-off" insertion pattern shows that the anterior, middle, and posterior tendons are inserted superior-medial, directly on, and inferior-lateral to the deltoid tuberosity and was found in 2/8 of our cadaveric specimens.
PubMed: 38707574
DOI: 10.1016/j.jseint.2024.01.013 -
JSES International May 2024Hemiarthroplasty (HHR) using a smaller head with rotator cuff reconstruction is a treatment option for cuff-tear arthropathy, offering advantages like facilitating...
BACKGROUND
Hemiarthroplasty (HHR) using a smaller head with rotator cuff reconstruction is a treatment option for cuff-tear arthropathy, offering advantages like facilitating rotator cuff-tear closure, increasing the lever arm of deltoid, and restoring function in irreparable cuff tears. This study aimed to evaluate the long-term outcomes of this procedure.
METHODS
A retrospective analysis was conducted for 91 shoulders undergoing HHR using a smaller head with rotator cuff reconstruction between May 2005 and September 2012. Surgery involved reducing the size of humeral head and performing rotator cuff reconstruction based on the site of the deficient rotator cuff. The study analyzed University of California, Los Angeles shoulder scores, Japanese Orthopaedics Association shoulder scores, range of motion, and postoperative radiographs.
RESULTS
Twenty-eight patients, divided into an elderly group (14 women, 2 men, mean age 74.5 ± 3.8 years) and a younger group (6 women, 6 men, mean age 63.5 ± 3.1 years) were followed up for a mean of 133.2 ± 14.1 months. No complications were reported. The clinical scores and range of motion significantly improved postoperatively and remained over 10 years. Radiographs revealed high incidence of glenoid wear (82.1%), bone resorption (43%) and cranial humeral head migration (54%), with no prosthesis loosening.
CONCLUSION
We believe that HHR using a smaller head with rotator cuff reconstruction is a surgical technique that can maintain stable long-term outcomes in both elderly and younger individuals with cuff-tear arthropathy.
PubMed: 38707560
DOI: 10.1016/j.jseint.2023.12.006 -
Musculoskeletal Surgery May 2024In end-stage arthritis indicated for total ankle arthroplasty (TAA), full-thickness cartilage damage, subchondral bone defect/shaving, and fluttering of the talar dome...
BACKGROUND
In end-stage arthritis indicated for total ankle arthroplasty (TAA), full-thickness cartilage damage, subchondral bone defect/shaving, and fluttering of the talar dome occur, shortening the distance between the tibial and talar insertions of ligaments and leading to laxity of ligaments surrounding the ankle joint. Under such conditions, medial ligaments (including the deltoid ligament) would not be expected to function properly. To stabilize the ankle joint during the stance phase, medial ligament function under tension is important. This study therefore examined whether TAA contributes to lengthening of the medial tibio-talar joint as evaluated radiographically, as a preferable method for achieving tensile effects on medial ligaments.
MATERIALS AND METHODS
Twenty-four feet with end-stage varus deformity of the ankle joint that underwent TAA were retrospectively investigated, excluding cases with any malleolar osteotomy or fracture. Distance between proximal and distal insertions of medial ligaments, lateralization of the talus, and talar tilt angle under valgus/varus stress condition were evaluated pre- and postoperatively.
RESULTS
Distance between proximal and distal insertions of medial ligaments was significantly elongated after TAA. At the same time, the talus showed significant lateralization. Furthermore, talar tilt under valgus/varus stress conditions was also significantly reduced after TAA.
CONCLUSION
TAA affects distal translation and lateralization of the talus in cases of varus ankle deformity. These effects might contribute to re-providing tensile force on lax medial ligaments, improving ligament function.
PubMed: 38705948
DOI: 10.1007/s12306-024-00820-6 -
JBJS Case Connector Apr 2024A 19-year-old woman sustained an open ankle fracture with complete destruction of the left medial malleolus and significant soft-tissue loss. After temporizing external...
CASE
A 19-year-old woman sustained an open ankle fracture with complete destruction of the left medial malleolus and significant soft-tissue loss. After temporizing external fixation and coverage with a rotational posterior tibial artery perforator flap, the medial malleolus was reconstructed with an autologous iliac crest bone graft and direct repair of the deltoid ligament. The patient achieved excellent improvement in functional outcomes at 21 months with adequate restoration of ankle motion.
CONCLUSION
This case shows reconstruction of the medial malleolus with autologous iliac crest bone graft after traumatic loss can be a viable treatment option for young patients.
Topics: Humans; Female; Ilium; Young Adult; Ankle Fractures; Autografts; Bone Transplantation; Fractures, Open; Plastic Surgery Procedures; Transplantation, Autologous
PubMed: 38704855
DOI: 10.2106/JBJS.CC.22.00559 -
Experimental Brain Research Jun 2024The anterior (DA) and posterior parts of the deltoid (DP) show alternating contraction during shoulder flexion and extension movements. It is expected that an inhibitory...
The anterior (DA) and posterior parts of the deltoid (DP) show alternating contraction during shoulder flexion and extension movements. It is expected that an inhibitory spinal reflex between the DA and DP exists. In this study, spinal reflexes between the DA and DP were examined in healthy human subjects using post-stimulus time histogram (PSTH) and electromyogram averaging (EMG-A). Electrical conditioning stimulation was delivered to the axillary nerve branch that innervates the DA (DA nerve) and DP (DP nerve) with the intensity below the motor threshold. In the PSTH study, the stimulation to the DA and DP nerves inhibited (decrease in the firing probability) 31 of 54 DA motor units and 31 of 51 DP motor units. The inhibition was not provoked by cutaneous stimulation. The central synaptic delay of the inhibition between the DA and DP nerves was 1.5 ± 0.5 ms and 1.4 ± 0.4 ms (mean ± SD) longer than those of the homonymous facilitation of the DA and DP, respectively. In the EMG-A study, conditioning stimulation to the DA and DP nerves inhibited the rectified and averaged EMG of the DP and DA, respectively. The inhibition diminished with tonic vibration stimulation to the DA and DP and recovered 20-30 min after vibration removal. These findings suggest that oligo(di or tri)-synaptic inhibition mediated by group Ia afferents between the DA and DP exists in humans.
Topics: Humans; Male; Adult; Electromyography; Deltoid Muscle; Female; Neural Inhibition; Young Adult; Electric Stimulation; Vibration; Afferent Pathways
PubMed: 38702470
DOI: 10.1007/s00221-024-06834-7 -
Anatomical Science International Jun 2024The shoulder joint has a high degree of freedom and an extremely complex and unstable kinematic mechanism. Coordinated contraction of the rotator cuff muscles that stop...
The shoulder joint has a high degree of freedom and an extremely complex and unstable kinematic mechanism. Coordinated contraction of the rotator cuff muscles that stop around the humeral head and the deltoid muscles and the extensibility of soft tissues, such as the joint capsule, labrum, and ligaments, contribute to shoulder-joint stability. Understanding the mechanics of shoulder-joint movement, including soft-tissue characteristics, is important for disease prevention and the development of a device for disease treatment. This study aimed to create a musculoskeletal shoulder model to represent the realistic behavior of joint movement and soft-tissue deformation as a dynamic simulation using a rigid-body model for bones and a soft-body model for soft tissues via a spring-damper-mass system. To reproduce the muscle-contraction properties of organisms, we used a muscle-expansion representation and Hill's mechanical muscle model. Shoulder motion, including the movement of the center of rotation in joints, was reproduced, and the strain in the joint capsule during dynamic shoulder movement was quantified. Furthermore, we investigated narrowing of the acromiohumeral distance in several situations to induce tissue damage due to rotator cuff impingement at the anterior-subacromial border during shoulder abduction. Given that the model can analyze exercises under disease conditions, such as muscle and tendon injuries and impingement syndrome, the proposed model is expected to help elucidate disease mechanisms and develop treatment guidelines.
Topics: Shoulder Joint; Humans; Biomechanical Phenomena; Models, Anatomic; Range of Motion, Articular; Rotator Cuff; Muscle, Skeletal; Computer Simulation
PubMed: 38698275
DOI: 10.1007/s12565-024-00773-7 -
Sports Medicine and Arthroscopy Review Mar 2024The study aimed to describe the changes in biomechanical properties of the supraspinatus tendon, deltoid muscle, and humeral head post arthroscopic rotator cuff repair...
The study aimed to describe the changes in biomechanical properties of the supraspinatus tendon, deltoid muscle, and humeral head post arthroscopic rotator cuff repair using shear wave elastography. Shear wave velocity of the tendon, deltoid, and humeral head of 48 patients was measured at predetermined sites at 1 week, 6 weeks, 12 weeks, 6 months, and 12 months post repair. One-way ANOVA with Tukey's correction and Spearman's correlation were performed. Mean±SEM healing tendon stiffness, adjacent to tendon footprint, increased from 1 week (6.2±0.2 m/s) to 6 months (7.5±0.3 m/s) and 12 months (7.8±0.3 m/s) (P<0.001). Mean±SEM deltoid muscle stiffness was higher at 12 months (4.1±0.2 m/s) compared to 1 week (3.4±0.1 m/s) and 12 weeks (3.5±0.1 m/s) (P<0.05). Humeral head stiffness did not change. Following arthroscopic rotator cuff repair, supraspinatus tendon stiffness increased in a curvilinear fashion over 6 months. From 6 months, deltoid muscle stiffness increased, corresponding to when patients were instructed to return to normal activities.
Topics: Humans; Biomechanical Phenomena; Male; Female; Rotator Cuff; Rotator Cuff Injuries; Middle Aged; Arthroscopy; Elasticity Imaging Techniques; Deltoid Muscle; Aged; Humeral Head
PubMed: 38695504
DOI: 10.1097/JSA.0000000000000386 -
Knee Surgery, Sports Traumatology,... May 2024When the intermediate or collicular fascicle of the medial collateral ligament (MCL) is injured, the diagnosis of posttraumatic medial ankle instability (MAI) is...
PURPOSE
When the intermediate or collicular fascicle of the medial collateral ligament (MCL) is injured, the diagnosis of posttraumatic medial ankle instability (MAI) is supported. The aim of this study was to describe an arthroscopic all-inside MCL repair after posttraumatic MAI secondary to an isolated injury of the MCL deep fascicle with a knotless suture anchor technique.
METHODS
Seven patients (seven men, median age: 23 [19-28] years) with posttraumatic MAI were treated by arthroscopic means after failing nonoperative management. The median follow-up was 34 (13-75) months. The MCL was repaired with an arthroscopic all-inside technique.
RESULTS
A tear affecting the deep and intermediate or collicular fascicle of the MCL was observed in all cases. In addition, five patients were diagnosed with an isolated fibular anterior talofibular ligament (ATFL) detachment, and in two patients, both the ATFL and calcaneofibular ligament were involved. All patients reported subjective improvement after the arthroscopic ligament repair. The median American Orthopedic Foot and Ankle Society score increased from 68 (range: 64-70) preoperatively to 100 (range: 90-100) at final follow-up.
CONCLUSION
Posttraumatic MAI can be successfully treated by an arthroscopic all-inside repair of the MCL. The presence of an MCL tear affecting the tibiotalar ligament fibres attached to the area of the anterior colliculus should be considered a sign of posttraumatic MAI. This partial deltoid injury at the level of the intermediate or collicular fascicle will conduct to a dynamic MAI.
LEVEL OF EVIDENCE
Level IV.
PubMed: 38690960
DOI: 10.1002/ksa.12197 -
Journal of Human Kinetics Mar 2024The current study compared the spatial excitation of the primary muscles during the lat pull-down exercise with the bar passing in front (front-LPD) or behind the neck...
The current study compared the spatial excitation of the primary muscles during the lat pull-down exercise with the bar passing in front (front-LPD) or behind the neck (back-LPD) using high-density electromyography. Fourteen resistance trained men performed a front-LPD or a back-LPD within a non-fatiguing set with 8-RM as the external load. The muscle excitation centroid of latissimus dorsi, middle trapezius, pectoralis major, biceps brachii, triceps brachii and posterior deltoid muscles were recorded during the ascending and the descending phase. During the descending phase, the front-LPD showed superior excitation of the latissimus dorsi (ES = 0.97) and the pectoralis major (ES = 1.17), while in the ascending phase, the back-LPD exhibited superior excitation of the latissimus dorsi (ES = 0.63), and the front-LPD showed superior excitation of the biceps brachii (ES = 0.41) and the posterior deltoid (ES = 1.77). During the descending phase, the front-LPD showed a more lateral centroid of the latissimus dorsi (ES = 0.60), the biceps brachii (ES = 0.63) and the triceps brachii (ES = 0.98), while the centroid was more medial for the middle trapezius (ES = 0.58). The centroid of the middle trapezius was also more medial in the front-LPD during the ascending phase (ES = 0.85). The pectoralis major centroid was more cranial in the front-LPD for both the descending (ES = 1.58) and the ascending phase (ES = 0.88). The front-LPD appears to provide overall greater excitation in the prime movers. However, distinct spatial excitation patterns were observed, making exercise suitable for the training routine.
PubMed: 38689585
DOI: 10.5114/jhk/185211