Preoperative Evaluation for Free Functional Muscle Transfer in Upper Extremity Amyoplasia: A Multicenter Report of 3 Cases.

CASE: A multicenter series of 3 patients with amyoplasia of the upper extremity were indicated for gracilis free functional muscle transfer (FFMT) to restore elbow flexion and found to have an absent gracilis. A final case is discussed detailing standardized evaluation with ultrasound to confirm gracilis before surgical intervention. CONCLUSION: In amyoplasia, the gracilis muscle may be absent or have fatty infiltration, making this donor muscle inadequate. Preoperative ultrasound to determine the presence of the gracilis is noninvasive and recommended in patients with amyoplasia of the upper extremity being considered for FFMT.

Using Next-Generation Sequencing to Understand Infection Prevention in Surgical Treatment of Upper Extremity Fractures-A Prospective Cohort Study.

INTRODUCTION: Postoperative fracture site infection can lead to notable patient morbidity, increase cost of care, and further contribute to healthcare disparities globally. Dogma suggests surgical blades as a vehicle for introducing bacteria into the surgical site; however, there is a paucity of literature to support this claim. This study uses advanced DNA sequencing to detect bacterial DNA on surgical blades used in upper extremity fracture surgeries. METHODS: This was a prospective study, conducted at a high-volume level 1 trauma center. All acute, closed upper extremity fractures requiring surgical stabilization were consecutively enrolled in a prospective fashion. The primary end point was the presence of bacterial DNA on the surgical blade using next-generation sequencing (NGS). At the time of surgery, two blades were sterilely opened. One blade served as the control while the other was used for the initial skin incision. Two negative control blades were opened directly into a sterile container. Two positive control blades were used for skin incision through known infections. All samples were sent for NGS analysis. RESULTS: Forty patients were enrolled in this study. The median age was 33.5 years, and 30% were female; the median body mass index was 26.52. Humerus fractures were the most common injury (N = 17, 42.5%), followed by clavicle fractures (13, 32.5%) and radius/ulna fractures (10, 25.0%). NGS analysis revealed no contamination of test blades used for skin incision. Three control blades tested positive for bacterial DNA. Negative control blades tested negative for bacterial DNA (0/2); the positive control blades resulted positive for bacterial DNA contamination (2/2). CONCLUSION: Surgical blades used for skin incision in the upper extremity are not contaminated with bacterial DNA as analyzed by NGS. This finding challenges previous surgical dogma regarding surgical blade contamination and supports that the same surgical blade can safely be used for deeper dissection. LEVEL OF EVIDENCE: Level II study: IRB approval-IRB#848938.

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

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. SIGNIFICANCE: 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.

Robotic assessment of bilateral and unilateral upper limb functions in adults with cerebral palsy.

BACKGROUND: Children with unilateral cerebral palsy (CP) exhibit motor impairments predominantly on one side of the body, while also having ipsilesional and bilateral impairments. These impairments are known to persist through adulthood, but their extent have not been described in adults with CP. This study's aim is to characterize bilateral and unilateral upper limbs impairments in adults with CP. METHODS: Nineteen adults with CP (34.3 years old ± 11.5) performed three robotic assessments in the Kinarm Exoskeleton Lab, including two bilateral tasks (Object Hit [asymmetric independent goals task] and Ball on Bar [symmetric common goal task]) and one unilateral task (Visually Guided Reaching, performed with the more affected arm [MA] and less affected arm [LA]). Individual results were compared to sex, age and handedness matched normative data, describing the proportion of participants exhibiting impairments in each task-specific variable (e.g., Hand speed), each performance category (e.g., Feedforward control) and in global task performance. Associations were assessed using Spearman correlation coefficients between: 1: the results of the MA and LA of each limb in the unilateral task; and 2: the results of each limb in the unilateral vs. the bilateral tasks. RESULTS: The majority of participants exhibited impairments in bilateral tasks (84%). The bilateral performance categories (i.e., Bimanual) identifying bilateral coordination impairments were impaired in the majority of participants (Object Hit: 57.8%; Ball on Bar: 31.6%). Most of the participants were impaired when performing a unilateral task with their MA arm (63%) and a smaller proportion with their LA arm (31%). The Feedforward control was the unilateral performance category showing the highest proportion of impaired participants while displaying the strongest relationship between the MA and LA arms impairments (rs = 0.93). Feedback control was the unilateral performance category most often associated with impairments in bilateral tasks (6 out of 8 performance categories). CONCLUSIONS: Adults with CP experienced more impairment in bilateral tasks while still having substantial impairments in unilateral tasks. They frequently display Feedforward control impairments combined with a higher reliance on Feedback control during both bilateral and unilateral tasks, leading to poorer motor performance.

Effects of basic movements and gait in the case of homolateral imitative synkinesis.

BACKGROUND: Homolateral Imitative Synkinesis (HIS) is a rare form of associative movement between the ipsilateral upper and lower limbs. The incidence of HIS or its correlation with various movements remains uninvestigated. This study expounds on the characteristics of HIS, the frequency at which it occurs, and its relationship with movement, particularly walking. METHODS: This study included 1328 patients with acute stroke admitted to our healthcare facility between October 2019 and February 2022. We evaluated the severity of motor paralysis and sensory impairment in instances where HIS manifested, and assessed the relationship between HIS, basic activities, and gait. RESULTS: HIS was observed in 13/1328 patients. Motor paralysis was mild in all the cases. Each patient displayed a degree of sensory impairment, albeit of varying severity. HIS did not manifest during basic activities but was evident during walking movements in five instances. These patients displayed involuntary repetitive lifting of their upper limbs during the swing phase of their gait. Some individuals expressed discontent with involuntary upper-limb movements, citing them as contributors to a suboptimal gait. CONCLUSIONS: This study identified HIS as a rare syndrome, manifesting at a rate of 0.9%. Focus was more common in patients with damage to the thalamus and parietal lobe. No manifestations of the HIS occurred during basic activities, suggesting a weak correlation between the HIS and such activities. Certain patients exhibit HIS during gait, report suboptimal gait, and have an increased risk of falls, potentially influencing their gait proficiency.

Risk of Upper Limb Diseases in Osteoarthritis Patients: A Propensity-score-matched Cohort Study.

BACKGROUND/AIM: Osteoarthritis (OA) is a prevalent degenerative joint disease that significantly impacts quality of life, particularly when affecting the hands. However, whether patients with OA are associated with higher risk of developing upper limb disorders, specifically trigger finger (TF) and carpal tunnel syndrome (CTS), remains unclear. This study aimed to evaluate the risk of upper limb disease in OA patients. PATIENTS AND METHODS: Using the US Collaborative Network, a subset of the TriNetX research network, we identified patients diagnosed with OA and matched them 1:1 with non-OA controls based on propensity scores. Matching covariates included age, sex, race, and comorbidities. The cohort consisted of 1,554,182 patients in each group. The hazard ratio of TF and CTS, as well as related surgical interventions, was assessed over a 5-year follow-up period. RESULTS: Patients with OA had a 1.30-fold increased risk of TF [95% confidence interval (CI)=1.27-1.33] and a 1.50-fold increased risk of CTS (95%CI=1.48-1.53) compared to controls. The hazard ratios for undergoing surgical interventions were 1.61 for TF (95%CI=1.51-1.71) and 1.97 for CTS (95%CI=1.78-2.19). These risks remained significant across various sensitivity analyses and stratifications according to age and sex. CONCLUSION: OA significantly increases the risk of TF and CTS. These findings highlight the need for vigilant monitoring and management of upper limb disorders in OA patients to improve overall patient care and outcomes. Future research is warranted to focus on pathological mechanisms of OA and their impact on upper limb health to develop targeted interventions.

Characterization and mapping of upper extremity fractures in children by a tertiary hospital quarantine and post-quarantine period.

OBJECTIVES: This study aims to categorize and map the incidence and patterns of upper extremity fractures in children during and after novel coronavirus disease 2019 (COVID-19) quarantine and to identify changes in the demographic characteristics and mechanisms of these fractures. PATIENTS AND METHODS: Between April 2020 and April 2022, a total of 3,549 upper extremity fractures occurring in 1,028 pediatric patients (682 males, 346 females; median age: 7 years; range, 0 to 18 years) were retrospectively analyzed. Those who presented between the dates of April 1st, 2020 and April 1st, 2021 (quarantine) were included in Group 1, whereas those who presented between April 1st, 2021 and April 2nd, 2022 (post-quarantine) were included in Group 2. The fracture map also showed the fracture density and location. RESULTS: There were statistically significant differences in terms of age range between Groups 1 and 2 (p<0.01). The 6-11 age range was significantly higher in Group 1, and the 12-18 age range was significantly higher in Group 2. CONCLUSION: Reducing physical activity during quarantine reduces fractures, particularly in adolescents. The removal of restrictions increases fractures in children in this age range. These findings highlight the importance of considering age ranges and physical activity levels while planning safety measures to prevent injuries in children.

Classification of upper limb spasticity patterns in patients with multiple sclerosis: a pilot observational study.

OBJECTIVE: The aim of this study was to provide a classification of the upper limb patterns in patients with upper limb spasticity due to multiple sclerosis. DESIGN: Pilot observational study. PATIENTS: Twenty-five adult patients with multiple sclerosis suffering from upper limb spasticity who underwent one segmental (i.e., proximal and distal upper limb) botulinum toxin treatment cycle were recruited. METHODS: Patients remained in a sitting position during the evaluation. Upper limb spasticity postures (i.e., postural attitude of a single joint/anatomical region) were evaluated and recorded for the shoulder (adducted/internally rotated), elbow (flexed/extended), forearm (pronated/supinated/neutral), wrist (flexed/extended/neutral) and hand (fingers flexed/thumb in palm). RESULTS: On the basis of the clinical observations, 6 patterns (i.e., sets of limb postures) of upper limb spasticity have been described according to the postures of the shoulder, elbow, forearm, and wrist. CONCLUSION: The patterns of upper limb spasticity in patients with multiple sclerosis described by this pilot study do not completely overlap with those observed in patients with post-stroke spasticity. This further supports the need to consider the features of spasticity related to its aetiology in order to manage patients appropriately.

Effectiveness of a Virtual Reality rehabilitation in stroke patients with sensory-motor and proprioception upper limb deficit: A study protocol.

INTRODUCTION: Stroke is the second leading cause of death in Europe. In the case of stroke survival (almost 70%), only 25% of patients recover completely, while the remaining 75% will undergo a rehabilitation phase that varying from months to years. The primary outcomes of a stroke involve motor impairment in the upper limbs, resulting in a partial or complete inability to move the limb on the right or left side, depending on the affected hemisphere. Furthermore, the motor deficit distorts the proprioception of the body and the embodiment ability of the injured limb. This could be rehabilitated through the paradigm of body illusion that modulates the motor rehabilitation. The present protocol aims to investigate the effectiveness of a Virtual Reality system for sensorimotor and proprioception upper limb deficit compared to a traditional upper limb rehabilitation program. METHOD: This study has a randomized and controlled design with control and experimental groups, and 4 measurement times: pre-intervention, immediately after the intervention, and two follow-ups (at 6 and 12 months). The inclusion criteria are: (a) Being 18 to 85 years old, both males and females; (b) Suffering from ischemic or haemorrhagic stroke; (c) The stroke event must have occurred from two to eighteen months before recruitment; (d) Patients must have moderate to severe upper limb motor deficit, and the alteration of sensorimotor and proprioception abilities of the injury upper limb; (e) Patients must understand and sign the written consent for enrolment. The rehabilitation last four weeks with three sessions per week at Bellaria Hospital of Bologna (Italy). The VR protocol uses two types of technology: immersive and non-immersive, and the control group follow the traditional rehabilitation program.

Timely Shaver Treatment Removes Chronic Tophaceous Mass Improve Surgical Outcomes.

Background: Current treatments with urate-lowering therapy (ULT) are effective for most patients with gout. However, approximately 10% of these patients do not respond well to ULT and develop chronic tophus lesions. Objective: This study aimed to evaluate the efficacy of surgery involving the shaver technique against chronic tophus lesions. Methods: This single-center, retrospective cohort study included 217 patients who had cumulatively undergone 303 shaver-assisted procedures between 2002 and 2018. Surgical outcomes were assessed in terms of the length of hospital stay (LOS) and wound healing time. Results: LOS and wound healing time were longer in patients with a preoperative tophus infection and lower extremity lesions than in those without infection and with upper extremity lesions (respectively, LOS: 12.7 vs. 8.6 days; wound healing time: 22.7 vs. 16.3 days). However, factors such as age, sex, body mass index, renal function, or uricemia level exerted no significant effect on surgical outcomes. Conclusion: Surgery involving the shaver technique should be performed before tophus infection. Clinical outcomes tend to be better for upper extremity lesions than for lower extremity lesions.

Designing and Analyzing In-Place Motor Tasks in Virtual Reality With Goal Functions.

Goal functions make virtual goal-oriented motor tasks easier to analyze and manipulate by explicitly linking movement to outcome. However, they have only been used to study constrained (e.g., planar) upper limb movements. We present a design framework for integrating goal functions with unconstrained postural and upper limb movements in a virtual reality (VR) device. VR tasks designed with the framework can mimic unconstrained natural motions and thus train a range of functional movements yet remain analytically tractable. We created three in-place VR motor tasks: a bow-and-arrow, a reach-and-strike, and a punching bag task. Each task was adjusted to subject-specific workspace limits and anthropometrics. We studied the effects of 3 days of practice and 3 reach/lean distances on task performance in 12 healthy adults. Subjects performed all tasks on day 1 with moderate proficiency and improved with practice at all reach/lean distances. Task-specific results showed that performance decreased and movement variability increased near the edge of the reaching workspace; viewing angles and the imperfect depth cues in VR likely led to biases in performance and practice could attenuate the former effect; in reach-and-strike, subjects learned movement patterns similar to those seen in a real-world striking sport. These results show that our framework can deliver tasks useful for analyzing and training motor performance and can guide future in-place motor training. Post-hoc, we demonstrated the feasibility of generalizable methods that adjust required movement speeds and task difficulty for impaired populations.

The influence of scaffolding on intrinsic motivation and autonomous adherence to a game-based, sparsely supervised home rehabilitation program for people with upper extremity hemiparesis due to stroke. A randomized controlled trial.

BACKGROUND: This parallel, randomized controlled trial examined intrinsic motivation, adherence and motor function improvement demonstrated by two groups of subjects that performed a 12-week, home-based upper extremity rehabilitation program. Seventeen subjects played scaffolded games, presenting eight to twelve discrete levels of increasing difficulty. Sixteen subjects performed the same activities controlled by success algorithms that modify game difficulty incrementally. METHODS: 33 persons 20-80 years of age, at least 6 months post stroke with moderate to mild hemiparesis were randomized using a random number generator into the two groups. They were tested using the Action Research Arm Test, Upper Extremity Fugl Meyer Assessment, Stroke Impact Scale and Intrinsic Motivation Inventory pre and post training. Adherence was measured using timestamps generated by the gaming system. Subjects had the Home Virtual Rehabilitation System (Qiu in J Neuroeng Rehabil 17: 1-10, 2020) placed in their homes and were taught to perform rehabilitation games using it. Subjects were instructed to train twenty minutes per day but were allowed to train as much as they chose. Subjects trained for 12 weeks without appointments and received intermittent support from study staff. Group outcomes were compared using ANOVA. Correlations between subject demographics and adherence, as well as motor outcome, were evaluated using Pearson Correlation Coefficients. RESULTS: There were 5 dropouts and no adverse events. The main effect of time was statistically significant for four of the five clinical outcome measures. There were no significant training group by time interactions. Measures of adherence did not differ significantly between groups. The combined groups improved their UEFMA scores on average by 5.85 (95% CI 4.73-6.98). 21 subjects from both groups demonstrating improvements in UEFMA scores of at least 5 points, exceeding the minimal clinically important difference of 4.25. IMI scores were stable pre to post training. CONCLUSIONS: Scaffolding challenges during game based rehabilitation did not elicit higher levels of adherence when compared to algorithm control of game difficulty. Both sparsely supervised programs of game-based treatment in the home were sufficient to elicit statistically significant, clinically meaningful improvements in motor function and activities of daily living. TRIAL REGISTRATION: Clinical Trials.gov-NCT03985761, Registered June 14, 2019.

Exploring age-related changes in motor function: insights from the peak decline found in Koji Awareness screening test.

The KOJI AWARENESS (KA) screening test assesses motor function in humans. We aimed to analyze the correlation between age and KA screening scores and to identify the specific age at which a significant decline occurs. A total of 793 healthy participants (234 females) were interviewed for basic information on age and sex and completed the KA screening test. In addition to calculating the total score from the KA test, the scores were calculated for the neck-scapula-upper extremity-complex (NSU), trunk, and lower extremity (LE) segments. Spearman's rank correlation coefficient was used to assess the validity of the test. Additionally, Bayesian linear regression was employed to estimate the change point in KA scores, facilitating the identification of a critical age associated with a notable decline in motor function. KA screening total and separate body segment scores were negatively correlated with age in both gender (for female and male, KA total score, ρ = - 0.443, ρ = - 0.344; NSU segment, ρ = - 0.431, ρ = - 0.427; trunk segment, ρ = - 0.210, ρ = - 0.473; LE segment: ρ = - 0.43, ρ = - 0.507). Furthermore, a change-point analysis using linear regression analysis showed that KA screening total scores declined sharply at the age of 49.1(95% credible interval: 37.503, 68.366). The result show that total KA scores decrease - 0.196 (95% credible interval: - 0.335, - 0.049) for every 1 year of age increase, and for ages over 49.1, total KA scores additionally decrease - 0.255 (95% credible interval: - 0.485, - 0.054) for every 1 year of age increase. In the NSU segment, females showed a more rapid decline than males from the age of 50 years. KA screening test total scores declined sharply at the age of 49.1. These results may be useful in setting treatment goals, exercise, and lifestyle programs for age-related decline in motor function.

Assessing the Effect of Cervical Transcutaneous Spinal Stimulation With an Upper Limb Robotic Exoskeleton and Surface Electromyography.

Transcutaneous spinal stimulation (TSS) is a promising rehabilitative intervention to restore motor function and coordination for individuals with spinal cord injury (SCI). The effects of TSS are most commonly assessed by evaluating muscle response to stimulation using surface electromyography (sEMG). Given the increasing use of robotic devices to deliver therapy and the emerging potential of hybrid rehabilitation interventions that combine neuromodulation with robotic devices, there is an opportunity to leverage the on-board sensors of the robots to measure kinematic and torque changes of joints in the presence of stimulation. This paper explores the potential for robotic assessment of the effects of TSS delivered to the cervical spinal cord. We used a four degree-of-freedom exoskeleton to measure the torque response of upper limb (UL) joints during stimulation, while simultaneously recording sEMG. We analyzed joint torque and electromyography data generated during TSS delivered over individual sites of the cervical spinal cord in neurologically intact participants. We show that site-specific effects of TSS are manifested not only by modulation of the amplitude of spinally evoked motor potentials in UL muscles, but also by changes in torque generated by individual UL joints. We observed preferential resultant action of proximal muscles and joints with stimulation at the rostral site, and of proximal joints with rostral-lateral stimulation. Robotic assessment can be used to measure the effects of TSS, and could be integrated into complex control algorithms that govern the behavior of hybrid neuromodulation-robotic systems.

A data-driven approach to detect upper limb functional use during daily life in breast cancer survivors using wrist-worn sensors.

To gain insights into the impact of upper limb (UL) dysfunctions after breast cancer treatment, this study aimed to develop a temporal convolutional neural network (TCN) to detect functional daily UL use in breast cancer survivors using data from a wrist-worn accelerometer. A pre-existing dataset of 10 breast cancer survivors was used that contained raw 3-axis acceleration data and simultaneously recorded video data, captured during four daily life activities. The input of our TCN consists of a 3-axis acceleration sequence with a receptive field of 243 samples. The 4 ResNet TCN blocks perform dilated temporal convolutions with a kernel of size 3 and a dilation rate that increases by a factor of 3 after each iteration. Outcomes of interest were functional UL use (minutes) and percentage UL use. We found strong agreement between the video and predicted data for functional UL use (ICC = 0.975) and moderately strong agreement for %UL use (ICC = 0.794). The TCN model overestimated the functional UL use by 0.71 min and 3.06%. Model performance showed good accuracy, f1, and AUPRC scores (0.875, 0.909, 0.954, respectively). In conclusion, using wrist-worn accelerometer data, the TCN model effectively identified functional UL use in daily life among breast cancer survivors.

Perspectives on the comparative benefits of body-powered and myoelectric upper limb prostheses.

BACKGROUND: Patient access to body-powered and myoelectric upper limb prostheses in the United States is often restricted by a healthcare system that prioritizes prosthesis prescription based on cost and perceived value. Although this system operates on an underlying assumption that design differences between these prostheses leads to relative advantages and disadvantages of each device, there is limited empirical evidence to support this view. MAIN TEXT: This commentary article will review a series of studies conducted by our research team with the goal of differentiating how prosthesis design might impact user performance on a variety of interrelated domains. Our central hypothesis is that the design and actuation method of body-powered and myoelectric prostheses might affect users' ability to access sensory feedback and account for device properties when planning movements. Accordingly, other domains that depend on these abilities may also be affected. While our work demonstrated some differences in availability of sensory feedback based on prosthesis design, this did not result in consistent differences in prosthesis embodiment, movement accuracy, movement quality, and overall kinematic patterns. CONCLUSION: Collectively, our findings suggest that performance may not necessarily depend on prosthesis design, allowing users to be successful with either device type depending on the circumstances. Prescription practices should rely more on individual needs and preferences than cost or prosthesis design. However, we acknowledge that there remains a dearth of evidence to inform decision-making and that an expanded research focus in this area will be beneficial.

A Novel De Novo Missense Mutation in KIF1A Associated with Young-Onset Upper-Limb Amyotrophic Lateral Sclerosis.

We investigate the etiology of amyotrophic lateral sclerosis (ALS) in a 35-year-old woman presenting with progressive weakness in her left upper limb. Prior to sequencing, a comprehensive neurological work-up was performed, including neurological examination, electrophysiology, biomarker assessment, and brain and spinal cord MRI. Six months before evaluation, the patient experienced weakness and atrophy in her left hand, accompanied by brisk reflexes and Hoffman sign in the same arm. Electroneuromyography revealed lower motor neuron involvement in three body regions. Neurofilament light chains were elevated in her cerebrospinal fluid. Brain imaging showed asymmetrical T2 hyperintensity of the corticospinal tracts and T2 linear hypointensity of the precentral gyri. Trio genome sequencing identified a likely pathogenic de novo variant in the KIF1A gene (NM_001244008.2): c.574A>G, p.(Ile192Val). Pathogenic variants in KIF1A have been associated with a wide range of neurological manifestations called KIF1A-associated neurological diseases (KAND). This report describes a likely pathogenic de novo variant in KIF1A associated with ALS, expanding the phenotypic spectrum of KAND and our understanding of the pathophysiology of ALS.

Superiority of High-Load vs. Low-Load Resistance Training in Military Cadets.

ABSTRACT: Øfsteng, SF, Hammarström, D, Knox, S, Jøsok, Ø, Helkala, K, Koll, L, Hanestadhaugen, M, Raastad, T, Rønnestad, BR, and Ellefsen, S. Superiority of high-load vs. low-load resistance training in military cadets. J Strength Cond Res 38(9): 1584-1595, 2024-Muscle strength and power are important determinants of soldiers' performance in modern warfare. Here, we compare the efficacy of 22 weeks of whole-body resistance training with high load (HL, 10 repetitions maximum/RM) and low load (LL, 30RM) for developing maximal muscle strength and power, performance, and muscle mass in moderately trained cadets (20 ± 1 year, f; n = 5, m; n = 22). Outcome measures were assessed at baseline and at week 22, in addition to a mid-intervention assessment at week 10. Twenty-two weeks of HL led to greater increases in muscle strength (upper limb, Δ 10%, 95% CI [2.8, 17.1], p = 0.01; lower limb, Δ 9.9%, CI [1.1, 18.6], p = 0.029), jump height (Δ 5.5%, CI [1.4, 9.6], p = 0.011), and upper limb lean mass (Δ 5.2%, CI [1, 9.4], p = 0.018) compared with LL. HL and LL led to similar changes in agility, muscle endurance performance, lower limb muscle mass, and cross-sectional area in m. vastus lateralis. For all variables, training-associated changes occurred primarily during the initial 10 weeks of the intervention, including the differential responses to HL and LL. In conclusion, although 22 weeks of HL led to greater increases in lower and upper limb muscle strength, power, and upper limb lean mass than LL, the 2 load conditions led to similar improvements in agility performance and lower limb muscle mass. Our results thus indicate that both loading regimes elicit multifaceted physiological improvements important for military readiness.

Eliciting Force and Slippage in Upper Limb Amputees Through Transcutaneous Electrical Nerve Stimulation (TENS).

Upper limb amputation severely affects the quality of life of individuals. Therefore, developing closed-loop upper-limb prostheses would enhance the sensory-motor capabilities of the prosthetic user. Considering design priorities based on user needs, the restoration of sensory feedback is one of the most desired features. This study focuses on employing Transcutaneous Electrical Nerve Stimulation (TENS) as a non-invasive somatotopic stimulation technique for restoring somatic sensations in upper-limb amputees. The aim of this study is to propose two encoding strategies to elicit force and slippage sensations in transradial amputees. The former aims at restoring three different levels of force through a Linear Pulse Amplitude Modulation (LPAM); the latter is devoted to elicit slippage sensations through Apparent Moving Sensation (AMS) by means of three different algorithms, i.e. the Pulse Amplitude Variation (PAV), the Pulse Width Variation (PWV) and Inter-Stimulus Delay Modulation (ISDM). Amputees had to characterize perceived sensations and to perform force and slippage recognition tasks. Results demonstrates that amputees were able to correctly identify low, medium and high levels of force, with an accuracy above the 80% and similarly, to also discriminate the slippage moving direction with a high accuracy above 90%, also highlighting that ISDM would be the most suitable method, among the three AMS strategies to deliver slippage sensations. It was demonstrated for the first time that the developed encoding strategies are effective methods to somatotopically reintroduce in the amputees, by means of TENS, force and slippage sensations.