Importance of muscle strength to maintain mobility, but not to maintain postural balance in older women: Cross-sectional study.

BACKGROUND: Acknowledging the relationship between postural control and muscle strength in lower limbs is important to find persons with high fall risk and to design fall prevention exercise programs. OBJECTIVE: To investigate the connection between knee muscle strength, semi-static postural balance, and functional mobility in irregularly active older women. METHODS: One hundred and ten older women aged 60 to 85 years underwent a semi-static postural balance test in a force and functional mobility measured by Timed Up & Go (TUG) with and without Cognitive Tasks (CT). Muscle strength of the knee was assessed by isokinetic dynamometry at 60°/s. RESULTS: A negative correlation between the functional mobility (TUG with and without CT) and the muscular strength of the knee was observed. Regarding semi-static balance, there was a low negative correlation with peak torque corrected for body weight of the extensors with the following variables with eyes open: Mean Velocity Dominant limb (D) (r = -0.19; p = 0.03); and anteroposterior range Non-Dominant limb (ND) (r = -0.19; p = 0.04); with eyes closed: mediolateral range ND limb (r = -0.21; p = 0.02) and Mean Velocity ND limb (r = -0.18; p = 0.05). CONCLUSIONS: This study found that better functional mobility was associated with greater muscle strength in the knee in elderly women. There were weak negative correlations between knee extensor strength and some measures of semi-static postural balance, suggesting that different motor control actions are required to maintain semi-static balance and mobility. In the case of semi-static balance, a lower level of muscle response is required than in functional mobility.

Effect of fatigue on knee biomechanics during the sidestep cutting manoeuvre: A modelling approach.

Loading both lateral and medial compartments is crucial to understanding the effect of muscle fatigue during sidestep cutting. The present study investigated the changes in tibiofemoral contact forces in the medial and lateral compartments and the muscle force contributions during the sidestep-cutting manoeuvre after a handball-specific fatigue protocol. Twenty female handball athletes performed three trials of the sidestep-cutting manoeuvre before (baseline) and after the fatigue protocol. Motion capture and ground reaction forces were measured, and the data were processed in OpenSim. The variables were compared using statistical parametric mapping (SPM), with a significance level of p < 0.05. The results showed a decreased knee flexion angle during fatigue in the early stance phase. In addition, the post-fatigue analysis demonstrated significantly reduced forces in vasti muscles. Similarly, during fatigue, the SPM analysis showed decreased tibiofemoral contact forces in the vertical and anterior directions. Vertical force applied to both medial and lateral condyles demonstrated a significant reduction after the fatigue protocol. These results indicated that forces applied to the tibiofemoral joint were reduced following the fatigue protocol compared to the baseline values. However, no consistent evidence exists that fatigue increases the risk of knee injuries.

Acute effect of static stretching and pilates stretching on the concentric muscle strength of the knee extensors and flexors.

INTRODUCTION: The effects of stretching exercises on muscle strength have been widely researched in the literature, however, there are no studies investigating the effects of Pilates stretching. OBJECTIVE: To compare the effects of static stretching and Pilates stretching on the concentric muscle strength of the knee extensors and flexors. METHOD: 102 trained young adults were randomized into three groups: static stretching (n = 33); Pilates stretching (n = 34); control (n = 35). Isokinetic evaluation of the knee extensor and flexor muscles was performed at 60°/s and 180°/s, pre and post acute intervention with stretching. Interventions in the static stretching and Pilates stretching groups occurred in 3 sets x 30 s for each body region considered (a-knee extensor muscles; b-knee flexor muscles). The control group did not perform any intervention. RESULTS: No difference (p > 0.05) was observed between the groups after the intervention. There was only a significant intragroup improvement for the control group on the isokinetic muscle strength of the knee flexors at 180°/s, with a moderate effect size, considering the entire sample (p = 0.040; d = 0.42) and when considering only male gender (p = 0.010; d = 0.60). CONCLUSION: Static stretching or Pilates stretching performed as a warm-up did not impair or enhance the concentric muscle strength performance of the knee extensors and flexors. In this way, both forms of stretching can be considered as preparatory exercises before muscle strength training.

30-sit-to-stand power is a better tool than isometric knee extensor strength to detect motor impairment in people with haemophilic arthropathy.

INTRODUCTION: Regular assessment of motor impairments is crucial in people with haemophilic arthropathy (PwHA). This study aimed to determine if there are differences in 30-seconds sit-to-stand (30-STS) power and maximal voluntary isometric contraction (MVIC) of the knee extensors between PwHA and healthy control group (CG). The secondary aims were to investigate the correlation between 30-STS power and MVIC of knee extensors with clinical characteristics and to assess their effectiveness in identifying motor impairment in PwHA. METHODS: A cross-sectional study was conducted by collecting data from PwHA (n = 17) and a sedentary CG (n = 15). MVIC (torque) and 30-STS power were normalised to body mass. Correlation analysis and simple linear regression adjusted for age were used to assess the association between tests and clinical variables. Using z-scores derived from the mean and standard deviation of the CG, we compared the MVIC and the 30-STS power in PwHA. RESULTS: PwHA showed lower MVIC and 30-STS power compared to CG (p < .001; large effect size d > .8). Lower 30-STS power was associated with greater joint impairment and greater fear of movement, whereas MVIC showed no association with clinical variables. 30-STS power showed a lower z-score compared to MVIC (p < .001). In addition, 30-STS power detected 47% of PwHA with motor impairment compared to 0% for MVIC (p = .002). CONCLUSIONS: Our results suggest that 30-STS power may be more effective than knee extensors MVIC in detecting motor impairment in PwHA. Consequently, lower limb skeletal muscle power, rather than maximum knee extensor strength, appears to be more affected in PwHA.

Exploring Human-Exoskeleton Interaction Dynamics: An In-Depth Analysis of Knee Flexion-Extension Performance across Varied Robot Assistance-Resistance Configurations.

Knee rehabilitation therapy after trauma or neuromotor diseases is fundamental to restore the joint functions as best as possible, exoskeleton robots being an important resource in this context, since they optimize therapy by applying tailored forces to assist or resist movements, contributing to improved patient outcomes and treatment efficiency. One of the points that must be taken into account when using robots in rehabilitation is their interaction with the patient, which must be safe for both and guarantee the effectiveness of the treatment. Therefore, the objective of this study was to assess the interaction between humans and an exoskeleton during the execution of knee flexion-extension movements under various configurations of robot assistance and resistance. The evaluation encompassed considerations of myoelectric activity, muscle recruitment, robot torque, and performed movement. To achieve this, an experimental protocol was implemented, involving an individual wearing the exoskeleton and executing knee flexion-extension motions while seated, with the robot configured in five distinct modes: passive (P), assistance on flexion (FA), assistance on extension (EA), assistance on flexion and extension (CA), and resistance on flexion and extension (CR). Results revealed distinctive patterns of movement and muscle recruitment for each mode, highlighting the complex interplay between human and robot; for example, the largest RMS tracking errors were for the EA mode (13.72 degrees) while the smallest for the CR mode (4.47 degrees), a non-obvious result; in addition, myoelectric activity was demonstrated to be greater for the completely assisted mode than without the robot (the maximum activation levels for the vastus medialis and vastus lateralis muscles were more than double those when the user had assistance from the robot). Tracking errors, muscle activations, and torque values varied across modes, emphasizing the need for careful consideration in configuring exoskeleton assistance and resistance to ensure effective and safe rehabilitation. Understanding these human-robot interactions is essential for developing precise rehabilitation programs, optimizing treatment effectiveness, and enhancing patient safety.

Tratamiento de la contractura en flexión de rodilla en parálisis cerebral / Treatment for knee flexion contracture in cerebral palsy

La extensión completa de la rodilla es esencial para la marcha. Los pacientes con parálisis cerebral infantil con frecuencia pueden tener déficit de extensión de distinta magnitud, lo que compromete la marcha e incluso la bipedestación. El tratamiento de la contractura en flexión de rodilla parte por tratar la espasticidad de los músculos comprometidos y con fisioterapia. Cuando el flexo es estructurado, el tratamiento es quirúrgico mediante distintas técnicas, dependiendo de la magnitud de la contractura y de la edad del paciente. Las técnicas sobre partes blandas incluyen alargamientos funcionales de isquiotibiales y transferencias musculares. Cuando la contractura es capsular, es preferible realizar cirugía ósea, la cual extiende el fémur proximal, ya sea en forma progresiva, mediante fisiodesis anterior en pacientes pediátricos, o en forma aguda, mediante osteotomía extensora del fémur distal. Con frecuencia existe una patela alta, la cual hay que corregir en el mismo acto quirúrgico para mantener la eficiencia del aparato extensor

Full knee extension is essential for gait. Patients with cerebral palsy frequently have extension deficits of different magnitudes, which compromise walking and even standing up. The treatment of knee flexion contracture begins by addressing the spasticity of the involved muscles and includes physical therapy. For structured extension deficits, the treatment is surgical, using different techniques depending on the magnitude of the contracture and the patient's age. Soft tissue techniques include functional hamstring lengthening and muscle transfers. For capsular contracture, bone surgery is preferable and extends the proximal femur either progressively, through anterior physiodesis in pediatric patients, or acutely, by extensor distal femoral osteotomy. A high patella is common and requires correction during the same surgical procedure to maintain the efficiency of the extensor apparatus

On the prediction of tibiofemoral contact forces for healthy individuals and osteoarthritis patients during gait: a comparative study of regression methods.

Knee osteoarthritis (OA) is a public health problem affecting millions of people worldwide. The intensity of the tibiofemoral contact forces is related to cartilage degeneration, and so is the importance of quantifying joint loads during daily activities. Although simulation with musculoskeletal models has been used to calculate joint loads, it demands high-cost equipment and a very time-consuming process. This study aimed to evaluate consolidated machine learning algorithms to predict tibiofemoral forces during gait analysis of healthy individuals and knee OA patients. Also, we evaluated three different datasets to train each model, considering different combinations of primary kinematic and kinetic data, and post-processing data. We evaluated 14 patients with severe unilateral knee OA and 14 healthy individuals during 3-5 gait trials. Data were split into 70% and 30% of the samples as training and test data. Test data was independently evaluated considering a mixture of pathological and healthy individuals, and only OA and Control patients. The main results showed that accurate predictions of the tibiofemoral contact forces were achieved using machine learning methods and that the predictions were sensitive to changes in the input data as training. The present study provided insights into the most promising regressions methods to predict knee contact forces representing an important starting point for the broader application of biomechanical analysis in clinical environments.

Patients With More Than 6.5° of Knee Hyperextension are 14.6 Times More Likely to Have Anterior Cruciate Ligament Hamstring Graft Rupture and Worse Knee Stability and Functional Outcomes.

PURPOSE: To create a cut-off point for hyperextension that best discriminates retear and to verify whether this cut-off point can predict retear regardless of other characteristics after primary anterior cruciate ligament (ACL) reconstruction with hamstrings autograft. METHODS: A cohort of patients submitted to primary isolated ACL reconstruction with hamstrings autografts was retrospectively evaluated. Patients were stratified according to the degree of passive knee hyperextension measured in the normal contralateral knee. The following data were collected: patient age and sex, time from injury to surgery, knee hyperextension, KT-1000 and pivot-shift, associated meniscus injury, intra-articular graft size, follow-up time, graft failure, and postoperative Lysholm and subjective International Knee Documentation Committee scores. RESULTS: Data from 457 patients were evaluated. Median age was 31 years. Thirty-two (7.0%) presented with retear. There was a significant difference in hyperextension between patients with and without retear (P < .001), with the cut-off point established by the receiver operating characteristic curve from 6.5°. Patients with greater hyperextension had a statistically greater frequency of women, longer injury time, greater intra-articular graft diameter, greater postoperative KT-1000, and greater frequency of retear, whereas the subjective International Knee Documentation Committee and Lysholm scores were statistically lower in patients with greater hyperextension. Only hyperextension showed a statistically significant association with re-rupture (P < .001). The odds of retear in patients with hyperextension greater than 6.5 was 14.65 times the odds of patients with hyperextension less than 6.5. CONCLUSIONS: Patients with more than 6.5° of hyperextension are 14.6 times more likely to have a graft rupture than patients with lower hyperextension when submitted to ACL reconstruction with hamstring tendons. Also, they present worse knee stability by the KT-1000 test and worse functional outcomes. Therefore, patients with this degree of hyperextension should not have isolated reconstruction with hamstrings as their first choice. LEVEL OF EVIDENCE: Level III, retrospective comparative prognostic trial.

Variables Associated With Knee Valgus in Male Professional Soccer Players During a Single-Leg Vertical Landing Task.

Prior studies have explored the relationship between knee valgus and musculoskeletal variables to formulate injury prevention programs, primarily for females. Nonetheless, there is insufficient evidence pertaining to professional male soccer players. Here, the aim was to test the correlation of lateral trunk inclination, hip adduction, hip internal rotation, ankle dorsiflexion range of motion, and hip isometric strength with knee valgus during the single-leg vertical jump test. Twenty-four professional male soccer players performed a single-leg vertical hop test, hip strength assessments, and an ankle dorsiflexion range of motion test. A motion analysis system was employed for kinematic analysis. Maximal isometric hip strength and ankle dorsiflexion range of motion were tested using a handheld dynamometer and a digital inclinometer, respectively. The correlation of peak knee valgus with peak lateral trunk inclination was .43 during the landing phase (P = .04) and with peak hip internal rotation was -.68 (P < .001). For knee valgus angular displacement, only peak lateral trunk inclination presented a moderate positive correlation (r = .40, P = .05). This study showed that trunk and hip kinematics are associated with knee valgus, which could consequently lead to increased knee overload in male professional soccer players following a unilateral vertical landing test.

Extraskeletal Intramuscular Chondroma of the Knee - Case Report and Review of the Literature / Condroma intramuscular extraesquelético do joelho - Relato de caso e revisão da literatura

Abstract Extraskeletal chondromas are small nodular cartilaginous lesions not attached to bone or the periosteum. They are rare tumors commonly occurring in the hands and feet. The objective of the present study is to describe a case of extraskeletal intramuscular chondroma (EIC) in the left knee and the diagnostic challenges faced by us. A 25-year-old female patient presented with slow-growing swelling in the left knee for 2 years. Clinically, the swelling was arising from the quadriceps muscle. We considered possibilities such as rhabdomyoma, neurofibroma, and intramuscular lipoma. Imaging studies suggested a benign fatty tumor. She was treated by excision. Microscopy was consistent with EIC without recurrence. A rare entity, clinically, EIC can mimic other benign soft-tissue tumors. Histopathology exams can provide a definitive diagnosis. The excision of the tumor is curative.

Resumo Os condromas extraesqueléticos são pequenas lesões cartilaginosas nodulares que não estão aderidas ao osso ou ao periósteo. São tumores raros que ocorrem comumente nas mãos e nos pés. Objetivo deste artigo é descrever um caso de condroma intramuscular extraesquelético (CIE) no joelho esquerdo e os desafios diagnósticos que enfrentamos. Uma paciente de 25 anos apresentou um edema de crescimento lento no joelho esquerdo havia 2 anos. Clinicamente, o edema era proveniente do músculo quadríceps. Foram consideradas possibilidades como rabdomioma, neurofibroma, e lipoma intramuscular. Os estudos de imagem sugeriram um tumor de gordura benigno. A paciente foi tratada com a excisão cirúrgica. A microscopia indicou CIE sem recorrência. O CIE é uma lesão rara. Clinicamente, pode ter aspecto semelhante ao de outros tumores benignos dos tecidos moles. A histopatologia pode fornecer um diagnóstico definitivo. A excisão cirúrgica do tumor é curativa.

Can We Forgo the Use of Tourniquets in Total Knee Arthroplasty? / Podemos dispensar o uso do torniquete nas artroplastias totais do joelho?

Abstract Objective To analyze whether there is more bleeding in patients undergoing total knee arthroplasty (TKA) without using a tourniquet. The secondary objectives were to analyze the operative time, the length of hospital stay, the need for transfusion, and the complication rate. Methods The present is a retrospective study through the analysis of medical records. The patients were divided into two groups: TKA with and without the use of a tourniquet. Reductions in the levels of hemoglobin and packed cell volume 24 h and 48 h after surgery, the operative time, the length of hospital stay, the need for transfusion, and the rate of complications up to 6 months postoperatively were compared between the groups. Results During the period analyzed, 104 patients underwent TKA, and 94 were included in the study. There were no differences between the groups regarding the mean values of hemoglobin and packed cell volume before surgery (p = 0.675 and p = 0.265), 24 h (p = 0.099 and p = 0.563), and 48 h (p = 0.569 and p = 0.810) after the procedure. Neither were there differences between the groups in terms of the operative time and the length of hospital stay (p = 0.484 and p > 0.05). Moreover, there were no differences regarding the need for transfusion and the complication rate. Conclusion It is possible to forgo the use a tourniquet in TKA without a significant change in hemoglobin and packed cell volume levels 24 h and 48 h after surgery when compared with the group using a tourniquet. There were no significant differences in the total operative time, length of stay, need for transfusion, and complication rate.

Resumo Objetivo Analisar se há mais sangramento em pacientes submetidos a artroplastia total do joelho (ATJ) sem a utilização do torniquete. Os objetivos secundários foram analisar os tempos cirúrgico e de internação, a necessidade de transfusão e a taxa de complicações. Métodos Estudo retrospectivo por meio da análise de prontuários. Os pacientes foram divididos em dois grupos: ATJ com e sem a utilização de torniquete. Foram comparados os valores das quedas da hemoglobina e do hematócrito 24 h e 48 h após a cirurgia, os tempos cirúrgico e de internação, a necessidade de transfusão e a taxa de complicações até 5 meses de pós-operatório. Resultados No período, foram operados 104 pacientes, sendo 94 incluídos no estudo. Não houve diferença entre as médias dos valores da hemoglobina e do hematócrito entre os grupos no pré-operatório (p = 0,675 e p = 0,265, respectivamente), 24 h (p = 0,099 e p = 0,563, respectivamente) e 48 h (p = 0,569 e p = 0,810, respectivamente) após a cirurgia. O tempo cirúrgico e o tempo de internação também não foram diferentes entre os grupos (p = 0,484 e p > 0,05, respectivamente). Não houve diferença com relação à necessidade de transfusões, nem com relação à taxa de complicações analisadas. Conclusão Podemos dispensar o uso do torniquete nas cirurgias de ATJ sem alteração significativa no valor dos níveis de hemoglobina e de hematócrito 24 h e 48 h após a cirurgia quando comparado ao grupo com uso de torniquete. Não houve diferenças significativas no tempo total das cirurgias, no tempo de internação, na necessidade de transfusões e nas taxas de complicações analisadas.

Quadricipital Tendon Simultaneous Bilateral Tear in a Patient with Type-II Diabetes Mellitus after Low-energy Trauma: Case Report / Ruptura bilateral simultânea do tendão quadricipital em paciente portador de diabetes mellitus do tipo II após trauma de baixa energia: Relato de caso

Abstract Simultaneous bilateral rupture of the quadricipital tendon is an extremely rare lesion. We report a case of this injury after low-energy trauma in a patient with type-II diabetes mellitus. Both knees were surgically approached in the same surgical procedure. Early rehabilitation is essential for the adequate functional recovery of the knee. The aim of the present report was to describe an atypical case of this type of injury after minimal trauma, as well as to detail the surgical technique used to treat it.

Resumo A ruptura bilateral simultânea do tendão do quadríceps é uma lesão extremamente rara. Relatamos um caso desta lesão após trauma de baixa energia em paciente portador de diabetes mellitus do tipo II. O diagnóstico é essencialmente clínico, e requer tratamento precoce. Os dois joelhos foram abordados cirurgicamente no mesmo ato operatório. A reabilitação precoce é fundamental para a recuperação funcional adequada do joelho. O objetivo deste relato foi descrever um caso atípico deste tipo de lesão após trauma mínimo, bem como detalhar a técnica cirúrgica utilizada para o tratamento.

Within- and between-day reliability and repeatability of neuromuscular function assessment in females and males.

The study evaluated the reliability and repeatability of the force and surface electromyography activity (EMG) outcomes obtained through voluntary and electrically evoked contractions of knee extensors in females (n = 18) and males (n = 20) and compared these data between sexes. Maximal isometric voluntary contractions (iMVCs) of knee extensors associated with electrical stimulation of the femoral nerve were performed over 4 days (48-h interval), with the first day involving familiarization procedures, the second involving three trials (1-h interval), and the third and fourth involving just one trial. The intraclass correlation coefficient (ICC), coefficient of variation (CV), and repeatability of outcomes from within- and between-day trials were determined for each sex. Females presented lower maximal voluntary force during iMVC (iMVCForce) and associated vastus lateralis EMG activity (root mean square, RMSVL), force evoked by potentiated doublet high-frequency (Db100Force) and single stimuli (Qtw), and M-wave amplitude than males (P ≤ 0.01, partial eta squared ≥0.94). Voluntary activation (VA) and RMSVL/M-wave amplitude did not differ between sexes. iMVCForce, VA, Db100Force, Qtw, and M-wave amplitude were the most reliable outcomes in within-day trials, with similar results between sexes (ICC > 0.62; CV < 6.4%; repeatability: 12.2%-22.6%). When investigating between-day trials, the iMVCForce, VA, Db100Force, and Qtw were the most reliable (ICC > 0.66; CV < 7.5%; repeatability: 13.2%-33.45%) with similar results between sexes. In conclusion, females presented lower iMVCForce and evoked response than males. Although reliability and repeatability statistics vary between trials, data (e.g., from EMG or force signal), and sexes, most of the outcomes obtained through this technique are reliable in females and males.NEW & NOTEWORTHY Although reliability and repeatability of knee extensors vary according to the type of neuromuscular function outcome (e.g., from force or EMG responses), the trial intervals (i.e., hours or days), and the sex of the participant, most force and EMG outcomes obtained through these neuromuscular assessment protocols present ICC > 0.75, very good CV (<10%), and repeatability <25% in within- and between-day trials in both sexes.

Eccentric Cycling Is an Alternative to Nordic Hamstring Exercise to Increase the Neuromuscular Function of Knee Flexors in Untrained Men.

ABSTRACT: Valdes, O, Inzulza, S, Collao, N, Garcia-Vicencio, S, Tufano, JJ, Earp, J, Venegas, M, and Peñailillo, L. Eccentric cycling is an alternative to Nordic hamstring exercise to increase the neuromuscular function of knee flexors in untrained men. J Strength Cond Res 37(11): 2158-2166, 2023-Nordic hamstring exercise (NHE) has been proposed to reduce knee flexor (KF) injuries. However, submaximal alternatives to NHE are necessary for the clinical or weaker population. The aim of this study was to compare the effects of Nordic hamstring training (NHT) and eccentric cycling (ECC) training on the neuromuscular function of the KF. Twenty healthy men (27.7 ± 3.5 years) were randomly assigned into 2 groups that performed 10 training sessions (2-3 sessions·week-1) of either NHT (n = 10) or ECC (n = 10). Maximal voluntary isometric contraction of the KF and knee extensor (KE) muscles (MVICKF and MVICKE) was measured, and the hamstring/quadriceps strength (H/Q) ratio was calculated. Furthermore, changes in NHE maximum reaction force (NHE-MRFKF), NHE break-point angle (NHE-BPA), and muscle activity of the semitendinosus (STEMG) and biceps femoris (BFEMG) during the NHE after the interventions were compared. Although no group × time effects were observed (p = 0.09-0.70), but time effects were found for all variables. Pairwise comparisons revealed that MVICKF (+16.9%; p = 0.02), H/Q ratio (+11.8%; p = 0.01), NHE-MRFKF (+19.8%; p = 0.005), and NHE-BPA (+30.8%; p = 0.001) increased after ECC, whereas NHE-MRFKF (+9.7%; p = 0.003), NHE-BPA (+35.5%; p = 0.0002), and STEMG (+33.7%; p = 0.02) increased after NHT. A group × time effect was observed (p = 0.003) in BFEMG, revealing an increase only after ECC (+41.1%; p < 0.0001). Similar neuromuscular adaptations were found after both training modalities. Therefore, ECC provides similar adaptations as NHT and may serve as an alternative form of KF training for those unable to perform NHE.

Performance of a Mobile 3D Camera to Evaluate Simulated Pathological Gait in Practical Scenarios.

Three-dimensional (3D) cameras used for gait assessment obviate the need for bodily markers or sensors, making them particularly interesting for clinical applications. Due to their limited field of view, their application has predominantly focused on evaluating gait patterns within short walking distances. However, assessment of gait consistency requires testing over a longer walking distance. The aim of this study is to validate the accuracy for gait assessment of a previously developed method that determines walking spatiotemporal parameters and kinematics measured with a 3D camera mounted on a mobile robot base (ROBOGait). Walking parameters measured with this system were compared with measurements with Xsens IMUs. The experiments were performed on a non-linear corridor of approximately 50 m, resembling the environment of a conventional rehabilitation facility. Eleven individuals exhibiting normal motor function were recruited to walk and to simulate gait patterns representative of common neurological conditions: Cerebral Palsy, Multiple Sclerosis, and Cerebellar Ataxia. Generalized estimating equations were used to determine statistical differences between the measurement systems and between walking conditions. When comparing walking parameters between paired measures of the systems, significant differences were found for eight out of 18 descriptors: range of motion (ROM) of trunk and pelvis tilt, maximum knee flexion in loading response, knee position at toe-off, stride length, step time, cadence; and stance duration. When analyzing how ROBOGait can distinguish simulated pathological gait from physiological gait, a mean accuracy of 70.4%, a sensitivity of 49.3%, and a specificity of 74.4% were found when compared with the Xsens system. The most important gait abnormalities related to the clinical conditions were successfully detected by ROBOGait. The descriptors that best distinguished simulated pathological walking from normal walking in both systems were step width and stride length. This study underscores the promising potential of 3D cameras and encourages exploring their use in clinical gait analysis.

Dose-response effect of lower limb resistance training volume on pain and function of women with patellofemoral pain: A systematic review and meta-regression.

OBJECTIVE: Analyze whether the effects of lower limb resistance training on pain and self-reported function were associated with the exercise volume prescribed for women with patellofemoral pain (PFP). METHODS: A systematic search was undertaken in four databases from inception to May 2023. Eligible trials examined the effects of resistance training programs on pain (visual analogue scale or numerical pain scale) and function (Anterior Knee Pain Scale) in women with PFP. Meta-analysis was undertaken with a random-effects model. The association of resistance training volume-related variables with mean difference effects on pain and function were tested by exploratory univariable meta-regression models. RESULTS: From 1,404 estudies retained for screening after duplicate removals, 16 studies (579 patients) were included. Changes in knee pain were inversely associated with weekly training frequency (ß = 0.5 ± 0.2, P = 0.012). No associations were found between the amount of resistance exercise prescribed per session or per week and effects on pain. Changes in function were associated with the number of sets per week (ß = 0.1 ± 0.1, P = 0.044) and number of sets per session (ß = 0.6 ± 0.2, P < 0.001) over the intervention. Most favorable results were achieved with 17 to 27 sets per session and >45 sets per week. CONCLUSIONS: The amount of prescribed resistance exercise does not seem to be critical for pain reduction in women with PFP. However, our findings support a dose-response effect in terms of improving function.

The bone mineral density and isokinetic knee strength in amputee soccer players.

OBJECTIVE: The aim of this study was to examine the isokinetic knee strength, H/Q ratio (%), and bone mineral density values between amputees (n=14; amputee soccer players) and healthy football players (n=14; non-amputee soccer players). METHODS: A total of 28 amputee soccer players and non-amputee soccer players participated in the study. An isokinetic dynamometer was used to determine the knee flexion/extension forces of the dominant legs of the athletes at 60, 180, and 240°/s. Bone mineral density scans were performed using dual-energy X-ray absorptiometry. RESULTS: H/Q ratio and 60º/s flexion and 180 and 240º/s flexion/extension strength (p<0.05) were found to be high (180º/s, p=0.03; 240º/s, p=0.048) in the non-amputee soccer player group. Accordingly, the bone mineral density values of the lumbar vertebra, femoral neck, proximal metaphysis of the femur (p<0.01), tibia/fibula proximal metaphysis, and tibia/fibula distal metaphysis (p<0.05) were found to be high. A correlation was observed between the 60º/s knee extension strength and tibia/fibula diaphyseal bone mineral density (p=0.025; r=0.594) and tibia/fibula distal metaphysis bone mineral density (p=0.017; r=0.623) values in the amputee soccer players group. The Z-scores of the amputee soccer players and non-amputee soccer players were in the expected range according to age (>-2). CONCLUSION: The bone mineral density, H/Q ratio, and all measured angular velocities of isokinetic strength were high in non-amputee soccer players. This finding made us think that lower extremity amputation may also be associated with losing strength. However, it was observed that the relationship between strength and bone mineral density in amputee athletes might vary according to different angular velocities. It is recommended that isokinetic strength measurement can be evaluated together with bone mineral density in athletes.

Development of a Control Strategy in an Isokinetic Device for Physical Rehabilitation.

Robotic-assisted rehabilitation is currently being applied to improve the effectiveness of human gait rehabilitation and recover the mobility and strength after a stroke or spinal cord injury; a robotic assistant can allow the active participation of the patient and the supervision of the collected data and decrease the labor required from therapists during the patient's training exercises. The goal of gait rehabilitation with robotic-based assistance is to restore motor function by using diverse control strategies, taking account of the physical interaction with the lower limbs of the patient. Over the last few years, researchers have extracted useful information from the patient's biological signals that can effectively reflect movement intention and muscle activation. One way to evaluate progress in rehabilitation is through isokinetic prototype tests that describe the dynamic characteristics of an isokinetic leg extension device for rehabilitation and control action. These tests use an isokinetic system to assess muscle strength and performance in a patient during isometric or isokinetic contraction. An experimental prototype shown in the following work allows the device's performance to be evaluated in a controlled environment before the patient's use. New features provide a control system that can be teleoperated for distributed structures, enabling the remote operation and management of the device. In order to achieve physical recovery from musculoskeletal injuries in the lower limbs and the reintegration of the affected subject into society as an independent and autonomous individual in their daily activities, a control model that introduces a medical isokinetic rehabilitation protocol is presented, in which the element that carries out such protocol consists of a magnetic particle brake whose control action is strongly influenced by the dynamics of the system when in contact with the end user-specifically, the patient's legs in the stretch from the knee to the ankle. The results of these tests are valuable for health professionals seeking to measure their patient's progress during the rehabilitation process and determine when it is safe and appropriate to advance in their treatment.

Knee skin temperature response of patients with bilateral patellofemoral syndrome before and after heat and cold stress.

Patellofemoral Pain Syndrome is characterized by the presence of pain in the front area of the knee, which occurs when performing common activities such as climbing stairs, and bending the knees, among others. The objective of this research was to evaluate the detection capability of infrared thermography in patients with Patellofemoral Pain Syndrome, in the baseline state, as well as after the application of thermal stress. The investigation was conducted in 48 patients, who were subdivided into four groups (n = 12). Two subgroups were healthy patients and two with Patellofemoral Pain Syndrome. For the diagnosis of the syndrome, a manual evaluation was performed using the Zohlen test and Q angle measurement. Subsequently, cold stress was applied for 10 min to a healthy subgroup and an experimental subgroup. The remaining two subgroups were subjected to heat stress for 15 min. Thermographic images of the lower extremities were acquired at seven time points, at baseline, immediately after application of thermal stress and then every 3 min until 15 min were completed. It was observed that patients presented Patellofemoral Pain Syndrome bilaterally. After statistical analysis, it was found that there were no significant differences in baseline temperature between the groups. However, for heat stress, a higher temperature was observed in the group with Patellofemoral Pain Syndrome (p < 0.05) in the recovery period, and in the case of cold stress, only a lower temperature in the left knee immediately after the application. In conclusion, it is not possible to detect patellofemoral syndrome bilaterally in the baseline state by thermography and neither is it evident in cold stress. However, after heat stress, thermal recovery is lower for the PFPS group, so it would be susceptible to detection.

Lower Limb Exoskeleton for Rehabilitation with Flexible Joints and Movement Routines Commanded by Electromyography and Baropodometry Sensors.

This paper presents the development of an instrumented exoskeleton with baropodometry, electromyography, and torque sensors. The six degrees of freedom (Dof) exoskeleton has a human intention detection system based on a classifier of electromyographic signals coming from four sensors placed in the muscles of the lower extremity together with baropodometric signals from four resistive load sensors placed at the front and rear parts of both feet. In addition, the exoskeleton is instrumented with four flexible actuators coupled with torque sensors. The main objective of the paper was the development of a lower limb therapy exoskeleton, articulated at hip and knees to allow the performance of three types of motion depending on the detected user's intention: sitting to standing, standing to sitting, and standing to walking. In addition, the paper presents the development of a dynamical model and the implementation of a feedback control in the exoskeleton.