Elbow Flexion Research Articles

The Effect of Exercises with Blood Flow Restriction in the Limbs on the Development of Muscle Strength and Hypertrophy: A Pilot Study

Weight training with regulated blood flow in the limbs is characterized by low load intensity ranging from 30-50% of the one repetition maximum. The aim of the study was to assess the effect of weight training with regulated blood flow in the limbs on changes in muscle strength and hypertrophy. The research sample consisted of 5 participants aged 26.40±7.16 years who performed 10-week intervention program. The weekly microcycle consisted of three training sessions, which intensity was regulated by inflatable cuffs placed on proximal parts of upper and lower limbs. Body composition was assessed with InBody 720. Muscle strength of knee and elbow flexors and extensors was assessed with Cybex HUMAC NORM isokinetic dynamometer at four speeds ranging from 60-240°·s-1, supplemented by front squat and bench press with emphasis on speed during the concentric phase of the movement. The results showed an increase in knee flexor muscle strength that was not statistically significant. The present pilot-study points to the need for further verification of methods how to use regulated blood flow in training related to muscle strength and hypertrophy.

Three-dimensional MRI analysis of elbow anatomy and kinematics in children with ulnar dimelia.

Ulnar dimelia often presents with restricted elbow movement. To develop a treatment strategy to improve elbow mobility, a detailed understanding of the skeletal deformity is needed. We created 3-D models of the cartilage and bone in the elbows of four children with ulnar dimelia by segmentation of MRI scans. We analysed the anatomy and performed a kinematic analysis. In all four children, the distal humerus was triangular in shape and consisted of a medial epicondyle, an enlarged lateral epicondyle and an anterior epicondyle. By comparing the 3-D images with conventional radiographs, we found that the projection of the enlarged lateral epicondyle created two longitudinal lines, which is a radiographic hallmark feature of the triangular-shaped distal humerus. In addition, during elbow flexion, the radial forearm bone slides along the lateral trochlea rather than rotates. This knowledge can aid surgeons to plan treatment for improving elbow mobility in ulnar dimelia.Level of evidence: IV.

Management of scoliosis in a pediatric patient with lysyl hydroxylase-3 deficiency: a case report

BackgroundA rare case report of lysyl hydroxylases deficiency undergoing scoliosis surgery.Case presentationAn 8-year-old Persian patient with a known case of lysyl hydroxylases deficiency presented with scoliosis. On physical examination, he had course facial hair, elbow flexion contracture, and knee flexion contracture. He had a history of eye surgery, clubfoot, and hearing problems. He underwent scoliosis surgery with growing rod instrumentation.ConclusionSurgery can be done in these patients with caution, and the surgeon and anesthesiologist should be aware of potential complications during and after surgery.

How to effectively prevent hamstring injury and acute treatment measures

Hamstring injury (HSI) is one of the most common injuries in competitive sports, the recurrence of this injury is high, which has a huge impact on the athlete's return to the game. Muscle strength, flexibility, muscle fatigue and age may contribute to damage to the hamstring. Current studies have shown that some static stretching, proprioceptive neuromuscular facilitation (PNF), warm-up and rest before and after the game, and the use of equipment such as foam shaft can effectively improve flexibility and prevent injuries, and hamstring strength training can also prevent injuries. The acute phase after injury can be managed by P.R.I.C.E principle to avoid aggravation of injury. This paper describes the dissolving structure, injury mechanism, risk factors, preventive measures and treatment of the hamstring muscle by citing literature and has a more comprehensive understanding of the prevention and treatment methods of hamstring muscle injury and provides some suggestions for athletes and rehabilitation therapists.

Estimation of the muscle force by perineural intramuscular electrical stimulation in healthy volunteers.

The present study aimed to evaluate the elbow flexor force induced by perineural intramuscular stimulation compared with surface electrical stimulation (ES) and maximal voluntary contraction. Thirty nondominant arms of healthy volunteers were evaluated. Isometric elbow flexion force was evaluated using a surface electrode stimulation at the biceps brachii muscle, a perineural intramuscular stimulation around the musculocutaneous nerve, and maximum voluntary contraction. The elbow flexion force was measured at the wrist volar area in a 90° elbow flexion posture, fixed with a rigid elbow orthosis. Pain and discomfort associated with ES were evaluated using a numeric rating scale. The mean maximum elbow flexion force was 16.6 ± 4.1 kgf via voluntary contraction. The mean elbow flexion force by ES was 2.9 ± 2.0 kgf, stimulation intensity was 24.8 ± 5.5 mA, and the numeric rating scale was 5.0 ± 2.5 via surface electrode stimulation and 3.1 ± 2.0 kgf, 5.0 mA, and 3.8 ± 1.9 via perineural stimulation, respectively. ES provides 16% to 18% of the maximal voluntary contraction force in elbow flexion, which corresponds to a fair grade of muscle force. Perineural intramuscular stimulation can generate an equivocal contraction force with less discomfort in elbow flexion than surface electrode stimulation.

Quantitative analysis of effectiveness and associated factors of exercise on symptoms in osteoarthritis: a pharmacodynamic model-based meta-analysis

ObjectiveThis study aims to evaluate the time point and magnitude of peak effectiveness of exercise and the effects of various exercise modalities for osteoarthritis (OA) symptoms and to identify factors...

Drop set versus traditional strength training protocols equated in volume on muscle thickness in women

Purpose: The aim of this study was to investigate the effects of two strength training protocols, equated in volume, on the elbow flexor muscle thickness (MT) in women. Methods: Twenty-seven women (mean±sd, age 21.89±2.85 years; stature,167.82±5.90 cm; body mass 63.01±7.20 kg; estimate of body fat mass, 19.19±2.88%) were divided in three experimental groups: a drop-set (DS), a traditional (TR), and a control group (CG). The CG maintained regular strength training without perform any upper body exercises. The DS group performed a dumbbell biceps curl for two days/week, 12 weeks, 4 sets of 3 blocks of 10 repetitions at 75%, 55%, and 35% of their 1 Repetition Maximum (RM), and 8 sets of 11 repetitions at 75% of the 1RM for the TR protocol. Rest interval between sets was 120 seconds. The MT was acquired in the anterior face of both upper arms at 50% and 60% of the distance between the lateral epicondyle of the humerus and the acromial process of the scapula before (T0) and after the 24 training sessions (T1). Results: There was a significant increase in all MT measurements between T0 and T1for the training groups(p<0.05). In addition, significantly higher values of MT were found in the training groups compared to the control group for all local measurements in T1 (p<0.05). No significant differences were found between training the groups for MT. Conclusion: It appears that both training groups (DS and TR), were effective in promoting MT of the elbow flexors muscles of young women with no differences between training strategies. Keywords: Hypertrophy, Ultrasonography, Training method, Female

The effect of tongue-to-palate on deep neck flexor activity

Deep neck flexor (DNF) muscles contribute to cervical stability and proprioception. Reduced muscle strength and endurance lead to faulty movement patterns, muscle imbalances, and dysfunction. Potentially, the orofacial muscles contribute to cervical strength by providing stability through muscular connections. This study examined effects of tongue muscle activity on cervical spine muscular stiffness. Twenty-three healthy subjects assumed three supine positions [at rest (AR), chin tuck (CT), and head lift (HL)] with and without tongue-to-palate pressure. The DNF stiffness was measured using shear wave elastography. Without tongue-to-palate, stiffness increased with CT and HL compared to AR (p <0.001) but not between CT and HL (p = 0.22). Tongue-to-palate increased stiffness AR (p <0.001) but not during CT (p = 0.95) or HL (p = 0.67). Stiffness levels between the AR and HL conditions during tongue-to-palate performance did not differ (p = 0.734), but CT stiffness was significantly greater than AR (p = 0.029) with tongue-to-palate. Tongue-to-palate AR increases DNF stiffness to a similar level as HL with or without tongue-to-palate, while CT with or without tongue-to-palate resulted in the highest stiffness levels. Tongue-to-palate pressure AR or with CT performance may be alternatives to HL strengthening in healthy necks. This may be a useful strategy to increase cervical stability during loads on the cervical spine.

Effects of Fatigue on Ankle Flexor Activity and Ground Reaction Forces in Elite Table Tennis Players.

Fatigue specifically affects the force production capacity of the working muscle, leading to a decline in athletes' performance. This study investigated the impact of fatigue on ankle flexor muscle activity and ground reaction forces (GRFs) in elite table tennis players, with a focus on the implications for performance and injury risk. Twelve elite male table tennis athletes participated in this study, undergoing a fatigue protocol that simulated intense gameplay conditions. Muscle activity of the soleus (SOL) and gastrocnemius lateralis (GL) muscles, heel height, and GRFs were measured using a combination of wireless electromyography (EMG), motion capture, and force plate systems. Results showed a significant decrease in muscle activity in both legs post-fatigue, with a more pronounced decline in the right leg. This decrease in muscle activity negatively affected ankle joint flexibility, limiting heel lift-off. Interestingly, the maximal anteroposterior GRF generated by the left leg increased in the post-fatigue phase, suggesting the use of compensatory strategies to maintain balance and performance. These findings underscore the importance of managing fatigue, addressing muscle imbalances, and improving ankle flexibility and strength to optimize performance and reduce the risk of injuries.

Preparation and application of organic hydrogels incorporating polyacrylamide/sodium alginate/DMSO for enhanced anti-drying, anti-freezing, and self-healing properties

The double-network hydrogel comprises two asymmetrically structured cross-linked networks, demonstrating exceptional mechanical properties and possessing significant potential for application in the field of flexible sensors. However, conventional hydrogels primarily disperse in water as a medium and continuously lose moisture in natural environments, rendering them incapable of retaining hydration over extended periods and unsuitable for utilization under low-temperature conditions. In this study, we devised an organic hydrogel based on polyacrylamide (PAM), sodium alginate (SA), and dimethyl sulfoxide (DMSO). Through hydrogen bonding interactions among DMSO molecules, polyacrylamide, and sodium alginate, this organic hydrogel not only exhibits anti-drying and anti-freezing properties but also demonstrates self-healing characteristics. Moreover, the organic hydrogel showcases remarkable mechanical properties and conductivity capabilities that render it suitable for constructing flexible strain sensors to monitor human movements such as finger bending, elbow flexion, knee joint bending, and ankle extension. Additionally, the sensor exhibits excellent stability and durability.

Are there kinematic and kinetic parameters correlated with racket velocity during the tennis serve? A preliminary comparison between a slow and a fast serve for performance improvement.

The tennis serve is a complex motion with numerous rotations which are important to manage for performance. The main aim of this study was to investigate kinematic parameters, including the evolution of the center of gravity, and kinetic parameters correlated with racket velocity over all phases of the tennis serve. The secondary objective was to find out which of the correlated parameters differed between a slow and a fast serve. The advantage of such an approach would be to propose biomechanical parameters that coaches and teachers could use to optimize performance or learn how to serve. Quantitative analysis was carried out on 5 flat serves performed by four ranked players using an optoelectronic system (82 markers located on whole body and racket) composed of 10 infrared cameras (150 Hz) and two force platforms (750 Hz). A descriptive statistical analysis highlighted 11 very large and almost perfect correlations with racket velocity: vertical ground reaction force of back foot in release backward, trunk axial rotation during loading phase, back and front knee flexions, dominant shoulder and hip mediolateral rotation during cocking phase, and center of gravity vertical velocity, dominant shoulder medial rotation velocity, dominant elbow flexion, trunk flexion/extension and axial rotation during acceleration phase. Differences were observed for some of the correlated parameters between slow and fast serve. Consequently, all these correlated kinematic and kinetics parameters constitute information that coaches, instructors and athletes can use to improve, optimize or teach the tennis serve.

Investigating premotor corticospinal excitability in fast and slow voluntary contractions of the elbow flexors.

Corticospinal excitability (CSE) increases prior to a voluntary contraction; however, the relative contributions of premotor cortical and spinal mechanisms are poorly understood. It is unknown whether the intended voluntary contractile rate affects CSE. Eighteen young, healthy participants (nine females) completed isometric elbow flexion contractions targeting 50% maximal voluntary contraction (MVC) torque, at either fast (fast as possible) or slow (25% MVC/s) contractile rates. Participants were cued to contract with warning (red) and "GO" (green) visual signals. Magnetic and electric stimulations were applied to elicit motor evoked potentials (MEPs), cervicomedullary evoked potentials (CMEPs), and M-waves, in the surface electromyogram (EMG) recorded over the biceps brachii. MEPs and CMEPs were collected at 0, 25, 50 and 75% premotor reaction time (RT - defined as the time between the "GO" cue and onset of biceps brachii EMG) and compared to a resting baseline. MEP amplitude was greater than baseline at 75% RT (p=0.009), and CMEP amplitude was significantly increased at all RT points relative to baseline (p≤0.001). However, there were no differences in MEP and CMEP amplitudes when compared between fast and slow conditions (p≥0.097). Normalized to the CMEP, there was no difference in MEP amplitude from baseline in either contractile condition (p≥0.264). These results indicate that increased premotor CSE is a spinally-mediated response. Furthermore, premotor CSE is not influenced by the intended voluntary contractile rate. CMEP amplitudes were larger for females than males within the premotor RT period (p=0.038), demonstrating that premotor spinal excitability responses may be influenced by sex.

Non-Invasive Muscle Metabolism Assessment with Near-Infrared Spectroscopy and Electrical Muscle Stimulation

Background: Muscle biopsy, the gold standard for assessing muscle aerobic capacity, is an invasive procedure. Noninvasive alternatives, such as 31-phosphorus magnetic resonance spectroscopy (31P-MRS) and near-infrared spectroscopy (NIRS), provide valuable insights, with NIRS providing superior time resolution and ease of use compared with 31P-MRS. Objectives: This study aimed to evaluate muscle metabolism using a 6 s muscle contraction phase with electrical muscle stimulation (EMS) and to assess the impact of EMS on exercise performance under hyperbaric conditions with elevated oxygen pressure. Methods: This study included nine male participants (21 ± 2 years) who underwent 5 min of EMS on the forearm flexor muscle group, with muscle oxygen dynamics assessed using NIRS. For statistical analysis, the mean values between groups were assessed using paired t-tests, and associations were evaluated using Pearson’s correlation coefficient. Results: Spontaneous blood flow interruption during EMS-induced muscle activity indicated the potential for assessing muscle metabolism without disrupting external blood flow. A significant negative correlation was observed between oxygen consumption and changes in oxygenated hemoglobin levels during muscle activity under hyperbaric conditions. Conclusions: This study demonstrates that skeletal muscle metabolism can be measured using a brief 6 s quantitative EMS. Furthermore, hyperbaric exercise appears to enhance aerobic capacity by increasing the rate and availability of oxygen consumption during exercise.

Influence of Neuromuscular Activity and Technical Determinants on Scull Rowing Performance

Rowing is a complex sport where technique can significantly impact performance. A better understanding of the rowers’ technique and neuromuscular activations during scull rowing, along with their impact on rowing performance, could greatly help trainers and athletes. Twelve male rowers were asked to row at their competitive stroke rate, and we collected data describing neuromuscular activations, trunk and arm kinematics, as well as technical determinants such as oar angles and angle asymmetries. We fitted linear mixed-effect models to investigate the effects of these variables on power production and boat speed. A larger effective angle had the greatest positive effect on power output, and slip angles had the largest negative effects. Increased elbow flexion at catch had the greatest negative effect on speed. Angle asymmetries affected neither power nor speed. Increased upper limb neuromuscular activity during the first and third quarters of the drive phase helped reduce slip angles, thus increasing performance. Power and speed were influenced similarly by the predictor variables. Still, they showed subtle differences, indicating that the strategies to maximize power production might not be the best ones to also achieve the maximum speed.

Maximum Isokinetic Eccentric Elbow Flexor Muscle Force Can Be Estimated Using Maximum Isometric Contraction Force.

Purpose It is difficult to measure maximal isokinetic eccentric (ECC) muscle strength in the sports field. This study aimed to investigate whether elbow isometric (ISO) flexion muscle strength or muscle thickness (MT) can be used to estimate elbow ECC flexion muscle strength. Material and methods Maximal muscle strength and muscle thickness (MT) were measured in the elbow flexor muscle group of 147 healthy adults (age: 21.3±0.8 years, height: 167.3±8.6 cm, body mass: 61.4±10.6 kg: 99 males and 48 females). Both isometric contraction (ISO) and eccentric contraction (ECC) of elbow flexion muscle strength were measured using an isokinetic dynamometer. The ultrasound measured MT at 50% of the distance from the upper arm to the lateral epicondyle. We performed the multiple regression analysis with elbow ECC flexion muscle strength as the dependent variable and gender, age, height, body mass, elbow ISO flexion muscle strength, and MT as the independent variables. Results Multiple regression analysis revealed a coefficient of determination R2 value of 0.89 and an adjusted R2 value of 0.89 (p<0.01). In addition, the independent variables elbow ISO flexor strength (p<0.01, standardized coefficient β=0.94; p<0.01, standardized coefficient β=0.89) and muscle thickness (p<0.05, standardized coefficient β=0.07) were identified as significantly associated factors. Conclusions The results suggest that it is possible to estimate elbow ECC flexion muscle strength using only elbow ISO flexion muscle strength and that ECC flexion muscle strength can be estimated more accurately by adding muscle thickness of the elbow flexor muscle group.

Nanograting-assisted flexible Triboelectric Nanogenerator for active human motion detection

This manuscript presents the development of a nanograting assisted Triboelectric Nanogenerator (TENG) for improved performance. The TENG leverages a cost-effective and straightforward fabrication method, utilizing nano-gratings on a Polydimethylsiloxane (PDMS) layer to enhance the triboelectric effect. The device characteristics are evaluated by considering tapping force, separation distance, and load resistance. The experimental electrical characterization shows that the output voltage increases significantly with higher applied forces, with a 2N force generating voltage increases of over 584% compared to a 0.1N force. Conversely, the output voltage decreases as the separation distance is reduced. The charge storage capability of the proposed device is demonstrated by integrating a TENG with a full-wave bridge rectifier. Furthermore, the fabricated TENG demonstrates remarkable sensitivity in detecting various body motions. When strategically placed on the biceps, the TENG effectively tracks muscle contraction and expansion with a voltage range of +0.5V to -1V, exhibiting a sensitivity of 1.5V per cycle. Similarly, the TENG accurately detects bending movements in the knee and elbow joints. For knee bending, the voltage output ranges from +2.5V to -1V, resulting in a sensitivity of 3.5V per cycle. Elbow flexion generates voltages between +4V and -5V, corresponding to a sensitivity of 9V per cycle. This clear correlation between voltage and specific body movements makes the TENG a promising candidate for wearable health and motion monitoring systems.

Muscle strength as a marker of metabolic health in kidney transplant recipients: A cross-sectional study

BackgroundMuscle strength is often used as an indirect indicator of metabolic health across different age groups in healthy individuals. However, in kidney transplant recipients, this measure may be less accurate due to metabolic changes induced by immunosuppressive medications. AimTo compare muscle strength between kidney transplant recipients with metabolic syndrome (MS) and those without this condition. MethodsA cross-sectional analytical study was conducted with 29 participants (22 men and seven women) aged 18–50 years, having undergone a kidney transplant for over a year and without experiencing graft failure. To determine the presence of MS, the criteria proposed by the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP-III) was used. Biochemical markers (triglyceride, total cholesterol, HDL, LDL, and glucose levels) were evaluated through a capillary sample. Muscle strength was assessed through three tests: long jump, elbow flexion, and grip strength. ResultsThe mean age was 36 ± 11.3 years, and the average transplant time was 4.5 ± 2.8 years. The prevalence of MS was 58.6%. Transplant recipients with MS performed less in all tests assessing muscle strength than those without this condition (p < 0.001∗). ConclusionsThe main finding of this research is that kidney transplant patients with MS performed worse in muscle strength tests compared to those without the condition.

Tendon Lengthening Surgery for Elbow Flexion Contractures in Brachial Plexus Birth Palsy

Flexion contracture of the elbow is a common deformity associated with brachial plexus birth palsy and is often managed with preventive night orthoses. For severe cases, however, surgical interventions may become necessary. This study evaluated the effectiveness of surgically releasing elbow flexion contractures exceeding 30° through partial tenotomy of the brachialis and biceps brachii muscles, along with a division of the lacertus fibrosus. We performed 36 anterior elbow releases on patients with injury to the upper trunk (C5-C6) of the brachial plexus and elbow flexion contractures between 30° and 80°. All releases involved lacertus fibrosus section and partial lengthening of the distal portion of the brachialis tendon. In severe cases, biceps brachii tenotomy was also performed. All participants had a minimum follow-up of 12 months and preoperative elbow flexion strength of at least grade 4 on the British Medical Research Council scale, with no deformities in the shape of the ulnohumeral joint or radial head subluxation. Following a mean follow-up of 41 months, the average extension gain was 31° (range, 10°-50°). All patients maintained their flexion strength. Except for two participants with weaker triceps, the mean elbow extension gain was sustained throughout the follow-up period. There were no major or minor complications or reinterventions in the study. Partial tenotomy of the brachialis and biceps brachii muscles, coupled with lacertus fibrosus section, is an effective treatment for elbow contractures exceeding 30° flexion. This method is successful in individuals with a functioning triceps brachii and elbow extension strength of at least grade 3 on the British Medical Research Council scale. Therapeutic IV.

Normative In-Game Data for Collegiate Baseball Pitchers Using Markerless Tracking Technology.

The current standard for motion capture data collection in baseball biomechanics is marker-based optical motion capture. Recent advancement in markerless motion capture capabilities has greatly improved accessibility to in-game, high-precision motion capture data, but specific values may differ from markered systems, necessitating separate normative values. For future data comparison, reference data are needed. To describe common kinematic variables in baseball pitching using an in-game markerless motion capture system. Descriptive laboratory study. Kinematic data were collected in 2 collegiate stadiums in the National Collegiate Athletic Association Division I Southeastern Conference using 8 synchronized 300-Hz KinaTrax cameras placed around the playing field. The in-game biomechanics data of 51 pitchers from 5 different teams during the 2023 season were collected; only pitchers with >3 outings during the season were included. After averaging all available fastballs thrown in the first inning of a game, we analyzed triaxial trunk (rotation, flexion, and lean) and pelvic rotation angles in the global reference frame, as well as shoulder rotation, shoulder horizontal abduction, shoulder abduction, elbow flexion, stride knee flexion, and hip-shoulder separation. A total of 509 fastballs were analyzed. Mean fastball velocity was 40.98 m/s (91.5 mph), with a vertical break of 42.0 ± 10.6 cm (16.5 ± 4.2 inches) and a horizontal break of 28.0 ± 11.1 cm (11.0 ± 4.4 inches). Mean stride length was 1.41 ± 0.08 m. The mean arm slot was 59.4°± 9.3°, and the mean upper arm slot was 72.9°± 9.3° at ball release. Additional normative time-series data are presented for commonly analyzed variables, and discrete metrics are provided at distinct time points in the pitching cycle. These data fill a need for separate norms for in-game, markerless motion capture performance metrics, and biomechanics for collegiate baseball pitchers to be used as reference values for researchers, coaches, and clinicians. Clinicians should use these results as reference values to contextualize injury mechanisms and the injury-performance trade-off. These data will also educate clinicians on what athletes' bodies must do to perform when constructing plans of care and return-to-play timelines.

Acute Effects Of Percussive Massage On Muscle Stiffness, Joint Stiffness And Flexibility In Healthy Individuals.

Acute Effects Of Percussive Massage On Muscle Stiffness, Joint Stiffness And Flexibility In Healthy Individuals.