Elbow Flexion Research Articles

Superficial Heat Therapy and Therapeutic Exercise in Individuals with Knee Osteoarthritis

Introduction: Knee Osteoarthritis is a major cause of pain and locomotor disability worldwide. Several physical therapy modalities have been recommended in reviewed clinical guidelines and systematic reviews, such as exercises, and electro and thermotherapy resources. Objective: This study evaluated the influence of the application of superficial heat therapy and/or therapeutic exercise on reducing pain and improving functional capacity in patients with knee osteoarthritis. Methods: 30 patients were divided into three groups (superficial heat, exercises, superficial heat plus exercises) and underwent 10 treatment sessions. Pain intensity was assessed using the visual analog scale; muscle flexibility with Wells’ bank test; strength gain with testing of one maximum repetition; walking time was analyzed with a walking test over a distance of 10 meters; and the Lequesne functional questionnaire was used to assess the functional activities of patients. Results: All treatments performed reduced knee pain. The exercise group showed an improvement in flexibility and quadriceps muscle strength. And the group that received superficial heat and therapeutic exercise showed better performance in time over a fixed distance covered. Conclusions: Therapeutic exercise and superficial thermotherapy performed in isolation showed beneficial effects in individuals with knee osteoarthritis. However, the therapeutic intervention carried out in combination showed better results in all parameters evaluated, suggesting that the clinical treatment can improve the quality of life of these individuals.

Influence of foot strike pattern on co-contraction around the ankle and oxygen uptake during running at 19 km/h.

This study investigated the coactivation of plantar flexor and dorsiflexor muscles and oxygen uptake during running with forefoot and rearfoot strikes at 15 and 19 km/h. We included 16 male runners in this study. The participants ran each foot strike pattern for 5 min at 15 and 19 km/h on a treadmill. During the running, respiratory gas exchange data and surface electromyographic (EMG) activity of the medial gastrocnemius (MG), lateral gastrocnemius (LG), soleus, and tibialis anterior muscles of the right lower limb were continuously recorded. The indices of oxygen uptake, energy expenditure (EE), and muscle activation were calculated during the last 2 min in each condition. During the stance phase of running at 15 and 19 km/h, activation of the tibialis anterior and MG muscles was lower and higher, respectively, with forefoot strike than with rearfoot strike. The foot strike pattern did not influence the oxygen uptake. These results suggest that the foot strike pattern has no clear effect on the oxygen uptake when running at 15 and 19 km/h. However, forefoot strike leads to plantar flexion dominance during co-contraction of the tibialis anterior and MG muscles, which are an antagonist and agonist for plantar flexion, respectively, during the stance phase.

Relationships between morphological features and physical performance depend on sex and age groups: a cross-sectional study among Brazilian beach volleyball players.

Understanding the evolution of morphological features and their relationship with physical performance may assist coaches and institutions in developing the next generation of beach volleyball (BV) athletes for senior-level competition. Thus, this study analyzed the morphological features of Brazilian BV athletes by sex among age groups, and their relationship with physical performance. A cross-sectional design was used to evaluate Brazilian BV players of both sexes in the U15 (11-14 years old, N.=21), U18 (15-17 years old, N.=21) and Senior (≥18 years old, N.=19) categories. The players underwent a series of kinanthropometric tests, including morphological (anthropometry, body composition and somatotype), neuromuscular (flexibility, handgrip strength, vertical jump [VJ], agility, and 5-m and 10-m maximum-speed sprints), and metabolic (VO<inf>2max</inf>) measurements. Welch analysis of variance (ANOVA) was used to compare the categories and the relationship between morphological and physical performance features was analyzed using Pearson's coefficient (r). Significant differences were found among the categories for female (body mass, skeletal muscle mass, hamstring flexibility, handgrip strength [HGS]) and male (body mass, height, BMI, skeletal muscle mass, flexibility, HGS, vertical jump, agility, maximum-speed sprints, and VO<inf>2max</inf>) players. Moreover, moderate, and strong correlations were identified between morphological features and physical performance (-0.90≤r≤0.89). The morphological and physical performance features of BV athletes varied among the U15, U18, and Senior categories, as expected due to their physical training process. Additionally, there are several morphological features that are correlated with physical performance, but the magnitude seems to depend on sex and category.

A Comparison of Throwing Arm Kinetics and Ball Velocity in High School Pitchers With Overall Fast and Overall Slow Cumulative Joint and Segment Velocities

Background: Individual maximum joint and segment angular velocities have shown positive associations with throwing arm kinetics and ball velocity in baseball pitchers. Purpose: To observe how cumulative maximum joint and segment angular velocities, irrespective of sequence, affect ball velocity and throwing arm kinetics in high school pitchers. Study Design: Descriptive laboratory study. Methods: High school (n = 55) pitchers threw 8 to 12 fastball pitches while being evaluated with 3-dimensional motion capture (480 Hz). Maximum joint and segment angular velocities (lead knee extension, pelvis rotation, trunk rotation, shoulder internal rotation, and forearm pronation) were calculated for each pitcher. Pitchers were classified as overall fast, overall slow, or high velocity for each joint or segment velocity subcategory, or as population, with any pitcher eligible to be included in multiple subcategories. Kinematic and kinetic parameters were compared among the various subgroups using t tests with post hoc regressions and multivariable regression models created to predict throwing arm kinetics and ball velocity, respectively. Results: The lead knee extension and pelvis rotation velocity subgroups achieved significantly higher normalized elbow varus torque (P = .016) and elbow flexion torque (P = .018) compared with population, with equivalent ball velocity (P = .118). For every 1-SD increase in maximum pelvis rotation velocity (87 deg/s), the normalized elbow distractive force increased by 4.7% body weight (BW) (B = 0.054; β = 0.290; P = .013). The overall fast group was older (mean ± standard deviation, 16.9 ± 1.4 vs 15.4 ± 0.9 years; P = .007), had 8.9-mph faster ball velocity (32.7 ± 3.1 vs 28.7 ± 2.3 m/s; P = .002), and had significantly higher shoulder internal rotation torque (63.1 ± 17.4 vs 43.6 ± 12.0 Nm; P = .005), elbow varus torque (61.8 ± 16.4 vs 41.6 ± 11.4 Nm; P = .002), and elbow flexion torque (46.4 ± 12.0 vs 29.5 ± 6.8 Nm; P < .001) compared with the overall slow group. A multiregression model for ball velocity based on maximum joint and segment angular velocities and anthropometrics predicted 53.0% of variance. Conclusion: High school pitchers with higher maximum joint and segment velocities, irrespective of sequence, demonstrated older age and faster ball velocity at the cost of increased throwing shoulder and elbow kinetics. Clinical Relevance: Pitchers and coaching staff should consider this trade-off between faster ball velocity and increasing throwing arm kinetics, an established risk factor for elbow injury.

Changes in brain functional connectivity and muscle strength independent of elbow flexor atrophy following upper limb immobilization in young females.

Muscle disuse induces a decline in muscle strength that exceeds the rate and magnitude of muscle atrophy, suggesting that factors beyond the muscle contribute to strength loss. The purpose of this study was to characterize changes in the brain and neuromuscular system in addition to muscle size following upper limb immobilization in young females. Using a within-participant, unilateral design, 12 females (age: 20.6±2.1years) underwent 14days of upper arm immobilization using an elbow brace and sling. Bilateral measures of muscle strength (isometric and isokinetic dynamometry), muscle size (magnetic resonance imaging), voluntary muscle activation capacity, corticospinal excitability, cortical thickness and resting-state functional connectivity were collected before and after immobilization. Immobilization induced a significant decline in isometric elbow flexion (-21.3±19.2%, interaction: P=0.0440) and extension (-19.9±15.7%, interaction: P=0.0317) strength in the immobilized arm only. There was no significant effect of immobilization on elbow flexor cross-sectional area (CSA) (-1.2±2.4%, interaction: P=0.466), whereas elbow extensor CSA decreased (-2.9±2.9%, interaction: P=0.0177) in the immobilized arm. Immobilization did not differentially alter voluntary activation capacity, corticospinal excitability, or cortical thickness (P>0.05); however, there were significant changes in the functional connectivity of brain regions related to movement planning and error detection (P<0.05). This study reveals that elbow flexor strength loss can occur in the absence of significant elbow flexor muscle atrophy, and that the brain represents a site of functional adaptation in response to upper limb immobilization in young females.

Hybrid Cooperative Control of Functional Electrical Stimulation and Robot Assistance for Upper Extremity Rehabilitation.

Hybrid systems that integrate Functional Electrical Stimulation (FES) and robotic assistance have been proposed in neurorehabilitation to enhance therapeutic benefits. This study focuses on designing a cooperative controller capable of distributing the required torque for movement between robotic actuation and FES, thereby eliminating the need for time-consuming calibration procedures. The control schema comprises three main blocks: a motion generation block that defines the desired trajectory, a motor control block including both a weight compensation feedforward and a feedback impedance controller, and an FES control block, based on trial-by-trial Iterative Learning Control (ILC), that adjusts the stimulation intensity according to a predefined stimulation waveform. The feedforward motor assistance can be dynamically regulated using an allocation factor. Experiments involving 12 healthy volunteers were conducted using a one-degree-of-freedom elbow testbed. The experimental results showcased the successful integration of Functional Electrical Stimulation (FES) with robotic actuation, ensuring precise trajectory tracking with a Root Mean Square Error (RMSE) below 7°. Notably, allocating more torque to FES led to a 51 % reduction in motor torque. In conditions where FES operated alone, there was poorer tracking performance with an RMSE of 24° and an early onset of muscle fatigue, as evidenced by a reduced number of achieved repetitions. Furthermore, the hybrid approach enabled 100 fatigue-free elbow flexion repetitions, underscoring the effectiveness of cooperative FES-motor control in extending the benefits of FES-induced exercises. This study proposes a flexible approach which can be extended to a multi-degree-of-freedom hybrid system. Furthermore, it underscores the significance of employing a straightforward and adaptable methodology with a rapid calibration procedure, making it easily transferable to clinical applications.

Quantifying Active and Passive Stiffness in Plantar Flexor Muscles Following Intermittent Maximal Isometric Contractions Using Shear Wave Elastography

ObjectiveThis study aimed: (i) to investigate the impact of fatigue, triggered by maximal isometric contraction exercises, on the active and passive stiffness of plantar flexors (PF), and (ii) to examine the relationship between changes in mechanical parameters and neuromuscular alterations after fatigue. MethodsA healthy cohort (n = 12; age = 27.3 ± 5.5 y; BMI = 24.4 ± 2.35 kg/m²) was instructed to perform 60 isometric contractions, each lasting 4 s with a 1-s rest interval, using an ergometer. Several measures were taken before and after the fatigue protocol. First, the stiffness of the PF-tendon complex (PFC) was quantified during passive ankle mobilization both during and after the fatigue protocol using the ergometer. Additionally, from shear wave elastography, the active and passive stiffness of the gastrocnemius medialis (GM) were measured during passive ankle mobilization and isometric maximal voluntary contraction (MVC), respectively. Finally, the peak torque and the rate of torque development (RFD) of PF were assessed during the MVC using the ergometer. Ankle muscle activities (surface electromyograph [SEMG]) were recorded during all evaluations using electromyography. ResultsAfter the fatigue protocol, the results revealed a decline in active stiffness, peak torque of PF, RFD and SEMG activity of the GM (p < 0.001). Furthermore, significant correlation was identified between the decrease of the peak torque of PF and the active stiffness of the GM (r = 0.6; p < 0.05). A decrease in the PFC stiffness (p < 0.001) and a decrease in the shear modulus of the GM at 20° (p < 0.001) were also observed. ConclusionIsometric fatiguing exercises modify the mechanical properties of both the contractile and elastic components. Notably, decreases in both passive and active stiffness may be critical for athletes, as these changes could potentially increase the risk of injury.

Comparison of trunk muscle endurance between women with and without chronic neck pain

PurposeTo compare trunk flexor, extensor, and lateral flexor muscle endurance between women with moderate to severe disability due to chronic neck pain (CNP) and asymptomatic women. DesignObservational case-control study. MethodsThirty women with CNP and Neck Disability Index scores ranging from 30% to 70% and 28 asymptomatic women were included. The visual analog scale was used to assess neck pain intensity at rest and during activity. To assess trunk muscles endurance, trunk flexor endurance test, Sorensen test, and side bridge endurance test were performed. ResultsAnalysis of covariance indicated that neck pain group had lower body mass index-adjusted endurance times of trunk flexor, extensor, and lateral flexor muscles with large effect sizes (p < .001, η2 = 0.378-0.696). Trunk flexor endurance time showed a moderately negative correlation with neck pain intensity at rest and a weakly negative correlation with neck disability score (r = –460 and –365, p < .05). ConclusionsWomen with moderate to severe disability due to CNP exhibited decreased trunk muscle endurance, which may be a predisposing factor for low back pain. Also, trunk flexor endurance was related to neck pain complaints. A holistic approach, addressing the entire spine rather than focusing solely on the cervical region, might be useful for managing CNP. Clinical ImplicationsThe findings of reduced endurance in trunk muscles should be considered when incorporating interventions in the management of CNP to effectively address pain and disability.

Passive bicycle training stimulates epiphyseal bone formation and restores bone integrity independent of locomotor recovery in a rat spinal cord injury model.

It is unknown whether activity-based physical therapy (ABPT) modalities that mobilize the paralyzed limbs improve bone integrity at the highly fracture-prone epiphyseal regions of the distal femur and proximal tibia following severe spinal cord injury (SCI). In this study, 4-mo-old skeletally mature littermate-matched male Sprague-Dawley rats received either SHAM surgery or severe contusion SCI. At 1 wk postsurgery, SCI rats were stratified to undergo no-ABPT, two 20-min bouts/day of quadrupedal bodyweight-supported treadmill training (qBWSTT), or hindlimb passive isokinetic bicycle (cycle) training, 5 days/wk for another 3 wk. We assessed locomotor recovery and plantar flexor muscle mass, tracked cancellous and cortical bone microstructure at the distal femoral and proximal tibial epiphyses using in vivo microcomputed tomography (microCT), and evaluated bone turnover at the tibial epiphysis with histomorphometry. All SCI animals displayed persistent hindlimb paralysis and pervasive muscle atrophy. Over the initial 2 wk, which included 1 wk of no exercise and 1 wk of ABPT acclimation, a similar magnitude of bone loss developed in all SCI groups. Thereafter, cancellous bone loss and cortical bone decrements increased in the SCI no-ABPT group. qBWSTT attenuated this trabecular bone loss but did not prevent the ongoing cortical bone deficits. In comparison, twice-daily cycle training increased the number and activity of osteoblasts versus other SCI groups and restored all bone microstructural parameters to SHAM levels at both epiphyseal sites. These data indicate that a novel passive isokinetic cycle training regimen reversed cancellous and cortical bone deterioration at key epiphyseal sites after experimental SCI via osteoblast-mediated bone anabolic mechanisms, independent of locomotor recovery or increased muscle mass.NEW & NOTEWORTHY This study was the first to assess how quadrupedal bodyweight-supported treadmill training or passive isokinetic bicycle (cycle) training impacts bone recovery at the distal femoral and proximal tibial epiphyses in a rat model of severe contusion spinal cord injury. Our results demonstrate that passive isokinetic cycle training completely restored cancellous and cortical bone microstructural parameters at these sites via osteoblast-mediated bone anabolic actions, independent of locomotor recovery or increased plantar flexor muscle mass.

Effects of Manual Therapy on Fascial Distortion Model in Adolescent Ankle Sprain: A Pilot Study

ObjectivesThe present study aimed to assess the feasibility of investigating the effects of manual therapy on ankle functional muscle strength, static balance, and disability in adolescent patients with an ankle sprain. MethodsThe study was a nonrandomized prepost clinical feasibility trial. From September 2021 to February 2022, 31 patients with ankle sprain received manual therapy. Functional muscle strength of plantar flexor muscles and static balance were evaluated using the standing heel-rise and unipedal stance tests on the injured and healthy legs before and after the first and second sessions. Foot and Ankle Disability Index (FADI) assessed the disability at baseline, after the first and second sessions, in the third and sixth weeks. ResultsWithin-group analysis of the unipedal stance test with open and closed eyes and the standing heel-rise test showed that injured legs significantly improved after the first and second sessions, compared to uninjured legs (P < .05). Furthermore, there were significant differences among all repeated FADI measures (P < .05). ConclusionsThis study demonstrated that a study was feasible to measure ankle functional muscle strength, static balance, and disability in adolescent patients with an ankle sprain.

Health-Related Physical Fitness and Biochemical Parameters in Overweight Older People during Social Isolation Imposed by the COVID-19 Pandemic: A Longitudinal and Observational Study.

With COVID-19, evidence indicates that the elderly will have worse biochemical markers related to health in social isolation. The objective was to analyze the impacts on physical fitness and biochemical parameters of older adults' health during COVID-19 social isolation. Quantitative, longitudinal, and observational study was conducted between 2020, 2021, and 2022. Thirty-three older adults of both sexes were evaluated. A sociodemographic questionnaire, biomarkers, and health-related physical fitness were used. Significant differences were observed for the sum of maximum isometric right and left handgrip strength, with a reduction in 2022 (p = 0.009); getting up and walking (p < 0.001), reduction in 2021 and 2022 (p < 0.05); elbow flexion and extension (p = 0.004), reduction in 2021 (p = 0.006); and sitting and standing (p = 0.002), reduction in 2022 (p = 0.003) and peak oxygen consumption (p < 0.001), reduction in 2021 and 2022 (p < 0.05). Differences were observed in fasting blood glucose (p < 0.001), with increase in 2021 and 2022 (p < 0.05), triglycerides (p < 0.001), with increase in 2021 and 2022 (p < 0.05), triglyceride-glucose index (p < 0.001), with increase in 2021 and 2022 (p < 0.05), triglyceride-glucose index with waist circumference (p < 0.001), with increase in 2021 (p < 0.001); and triglyceride-glucose index with body mass index (p < 0.001), with increase in 2021 (p < 0.001). However, no differences were observed between anthropometric and body composition (p > 0.05). Conclusions: Older people had changes in biochemical and physical fitness parameters related to health during the social isolation of the COVID-19 pandemic.

Effect of Circuit Training and Interval Training on Health Related Physical Fitness of Physical Education Professional Students

Abstract: The purpose of this study was to know the effect of circuit training and interval training on health related physical fitness of physical education professional students. Ninety boys belonging to B.P.Ed class of Govt. College of physical Education, Bhubaneswar age ranging between 22 to 25 years acted as subjects and assigned to three groups (two experimental and one control group) with 30 students each. The two experimental groups were Circuit Training and Interval Training groups. Health related physical fitness parameters such as Abdominal Muscle Strength (Sit Up), Flexibility (Sit and Reach), Cardiovascular Endurance (1 Mile Run), and Body Fat % (Triceps and Sub-Scapular Skin fold) were measured before and after training. All the experimental Groups (Circuit training and Interval training) was administered with the selected exercises, thrice in a week for a duration of 8 weeks under direct supervision of the research scholars. The analysis of data revealed that the three experimental groups, showed significant gains in performance of health related physical fitness after administration of training for duration of 8 weeks. The control group did not show any significant increase in the performance

Effect of Dry Needling Plus Static Stretching on Plantar Flexors Spasticity in Chronic Stroke Patients.

Stroke is a leading cause of disability worldwide and is often accompanied by complications such as spasticity. Static stretching (SS) is a common physiotherapy intervention for reducing spasticity, whereas dry needling (DN) is a novel approach. However, the combined effects of DN and SS on spasticity have not been thoroughly investigated. Given the pivotal effect of spasticity on daily activities, mitigating spasticity can significantly contribute to restoring patient independence. This study will explore the impact of DN plus SS on spasticity, alpha motor neuron excitability, overall function, and quality of life in patients with chronic stroke. A double-blind, randomized, sham-controlled trial will be conducted in patients with post-stroke spasticity in the plantar flexor muscles. Twentyeight participants will be randomly assigned to either an intervention or control group. The intervention group will receive DN (60s × 3 days/week; 1 week) plus SS (20 min × 5 days/ week; 1 week). The control group will undergo sham DN (60s × 3 days/week; 1 week) and SS (20 min × 5 days/week; 1 week). DN plus SS or sham DN plus SS. Both groups will be assessed at baseline, immediately post-treatment, and after 1 week of follow-up. Outcome measures will include the Modified Modified Ashworth Scale, H-reflex latency, Hmax/Mmax ratio, active and passive ankle dorsiflexion range of motion, timed up and go test, and the EuroQol questionnaire. Results from this randomized, sham-controlled study will provide evidence for the effectiveness of DN in combination with SS for spasticity. The additional impact of DN in conjunction with SS, a widely used method for reducing muscle tone, remains unclear and warrants investigation. This study, with a high level of evidence, aims to address this knowledge gap.

The Effect of Stretching on Lumbar Muscle Flexibility, Isokinetic Parameters and Lower Extremity Function

The Effect of Stretching on Lumbar Muscle Flexibility, Isokinetic Parameters and Lower Extremity Function

The recovery and independence of elbow flexion and forearm supination after Oberlin II transfer in brachial plexus injuries: a long term follows up study.

The Oberlin II double fascicular nerve transfer has been evaluated extensively for objective outcomes for elbow flexion in brachial plexus injuries (BPI). However, there is limited information available on the recovery pattern of supination and patient-reported activity in the long-term. Our study aimed to assess the functional results with a minimum of five years of follow-up. We evaluated patients with a minimum of five years after the Oberlin II procedure for post-traumatic BPI. They were evaluated using MRC grading, range of active movements, QuickDASH score and activity to check elbow flexion and forearm supination independent of finger and wrist flexion. 18 out of 26 patients responded with a mean follow-up of 79.4months (range: 61-98). 16 (88.9%) (p < 0.000) patients recovered to achieve active elbow flexion and forearm supination of either MRC grade 3 power or more. The average range of active elbow flexion was 113.9° (range: 0-140°) and active supination was 67.8° (0-90°). Patients who achieved grade 3 flexion or higher were found to regain supination after a delay. The recovery continues even after two years of surgery. The mean QuickDASH score was 21.8 (range: 2.3-63.6). There's a significant inverse correlation between QuickDASH with both flexion and supination (p < .001 and < 0.05). 15 patients (83.3%) could demonstrate a dissociation of elbow and forearm movements from digital and wrist movements. Our study demonstrated reliable functional results with independent elbow flexion, forearm supination and acceptable patient-reported outcomes for Oberlin II procedure in BPI.

Load Changes on a Short-Segment Posterior Instrumentation After Transosseous Disruption of L3 Vertebra - A Biomechanical Human Cadaveric Study.

Biomechanical Cadaveric Study. Following the successful use of a novel implantable sensor (Monitor) in evaluating the progression of fracture healing in long bones and posterolateral fusion of the spine based on implant load monitoring, the aim of this study was to investigate its potential to assess healing of transosseous fractures of a lumbar vertebra stabilized with a pedicle-screw-rod construct. Six human cadaveric spines were instrumented with pedicle screws and rods spanning L3 vertebra. The spine was loaded in Flexion-Extension (FE), Lateral-Bending (LB) and Axial-Rotation (AR) with an intact L3 vertebra and after its transosseous disruption, creating an AO B1 type fracture. The implant load was measured on the one rod using the Monitor and on the contralateral rod by strain gauges to validate the Monitor's measurements. In parallel, the range of motion (ROM) was assessed. ROM increased significantly in all directions in the fractured model (P ≤ 0.049). The Monitor measured a significant increase in implant load in FE (P = 0.002) and LB (P = 0.045), however, not in AR. The strain gauge - aligned with the rod axis and glued onto its posterior side - detected an increased implant load not only in FE (P = 0.001) and LB (P = 0.016) but also in AR (P = 0.047). After a complete transosseous disruption of L3 vertebra, the implant load on the rods was considerably higher vs the state with an intact vertebral body. Innovative implantable sensors could monitor those changes, allowing assessment of the healing progression based on quantifiable data.

Effectiveness of High-Intensity Circuit Training on Physical Fitness Among Athletes: A Systematic Review of Randomized-Controlled and Non-Controlled Trials

Background and Aim of the Study: The continuous evolution of sports and athletics necessitates innovative training strategies to optimize athletes’ performance and physical fitness. High-Intensity Circuit Training (HICT) has emerged as a time-efficient method that combines high-intensity exercises with minimal rest, targeting various muscle groups to enhance physical fitness components. Therefore, this systematic review aims to evaluate the effectiveness of HICT on physical fitness components among athletes to provide a clear, evidence-based understanding of HICT’s benefits and limitations. Material and Methods: A comprehensive search strategy was employed, retrieving articles published before September 24, 2023, from databases including the Cochrane Central Register of Controlled Trials, PubMed, and Google Scholar. The selection process followed the PRISMA guidelines, focusing on studies that assessed the impact of HICT on athletes’ physical fitness. The quality of included studies was assessed using the PEDro scale, and data synthesis was conducted to summarize findings on various physical fitness components. Results: The review included 13 studies, highlighting HICT’s positive effects on muscle strength, endurance, flexibility, balance, power, body composition, and cardiovascular endurance. Improvements were noted in neuromuscular efficiency, muscle power, coordination, and cardiovascular fitness, which are crucial for athletic performance. However, the review also identified variability in training adaptations and the need for sport-specific exercises to maximize the benefits of HICT for speed and power enhancements. Conclusions: HICT is a versatile and effective training modality that can significantly improve various aspects of athletes’ physical fitness. Incorporating targeted, sport-specific exercises into HICT programs could further optimize performance enhancements. Despite promising findings, the review acknowledges methodological heterogeneity among studies and calls for further research to refine HICT protocols for athletes.

Trunk Flexor and Extensor Muscle Strength Capacity in Healthy Individuals

Objective: Generating reference values of trunk muscle strength is of value for specific age groups and gender in every society. The aim of this study was to define flexor and extensor muscle strength of the trunk and the flexion/extension ratio in healthy individuals. Materials and Methods: Hundred and two healthy individuals were included in this study. Isokinetic concentric strength of trunk flexor (Flex) and extensor (Ext) muscles of the participants were measured via an isokinetic dynamometer. Tests were performed at speeds of 60°/s and 180°/s. Maximum strength was characterized with peak torque (PT) (Flexabs, Extabs; N·m), peak torque normalized to body weight (PTNBW) (Flexnorm, Extnorm; N·m·kgbw-1), and Flexabs/Extabs ratio. Results: For angular velocity of 600/s, PT and PTNBW of flex and ext strength were higher in men; while for angular velocity of 1800/s, PTNBW of flex and ext strength were higher in women (p&lt;0.05). Extensor strength for 600/s and 1800/s angular velocities yielded lower values than flexor strength in both genders. The Flexabs/Extabs ratios were 1.67±0.62 for 600/s and 4.93±4.60 for 1800/s. Conclusion: Trunk extensor strength was higher than flexor strength in men and women at 600/s and 1800/s angular velocities. In this study, the ratio of Flexabs/Extabs was not within the accepted range in non-active adults and there was no difference between men and women, indicating that muscle strength is not sufficient in this population. The data of this study can be used as a comparison parameter in future studies to get normative data, or common values in healthy individuals aged 18-30.

Movements classification system for transhumeral amputees using myoelectric signals

The extent of loss of functionality in people with transhumeral amputation or elbow disarticulation is considered highly compromised. The person with this impairment loses the primary muscle involved in the movement of the hand and fingers, and the elbow flexion/extension. In this sense, the development of myoelectric prostheses must include mechanisms that replicate these movements. Moreover, the control system for controlling a prosthesis must be robust and intuitive, where pattern recognition and artificial intelligence techniques represent an important and increasingly explored alternative. This study aims to develop a movement intention classification system based on myoelectric signals (MES) obtained from an elbow disarticulation amputee. Different features were extracted from the MES as the Mean absolute value (MAV), zero crossings (ZC), slope sign changes (SSC), waveform length (WL), and autoregressive (AR) coefficients. Machine learning classifiers (Linear Discriminant Analysis (LDA), Quadratic Discriminant Analysis (QDA), Support Vector Machines (SVM), K-Nearest Neighbors (KNN), Random Forests (RF), and Multilayer Perceptron (MLP)) were used to predict seven gestures: elbow flexion (EF), elbow extension (EE), forearm pronation (FP), forearm supination (FS), hand opening (HO), hand closing (HC), and rest (R). The results obtained with LDA, QDA, KNN, MLP, SVM, and RF were 60.84%, 71.05%, 77.10%, 78.06%, 78.57%, and 79.72% of accuracy, respectively. These results are promising and will allow the development of a myoelectric prosthesis control system for people with transhumeral amputation or elbow disarticulation.

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.