Straight Knee Research Articles

Foot Posture and Ankle Dorsiflexion as Risk Factors for Developing Achilles Tendinopathy and Plantar Fasciitis: A Case-Control Study.

Plantar fasciitis (PF) and Achilles tendinopathy (AT) are common injuries that primarily affect people engaged in sport or occupational weightbearing activities. Identifying modifiable risk factors is important for the treatment and prevention of these injuries. The purpose of this study was to evaluate whether foot posture or ankle dorsiflexion are risk factors for developing AT or PF, and if there were any differences between PF and AT patients. This was a case-control study of 108 patients with PF and 114 patients with AT, compared to the same number of referred patients in 2 control groups never having had these injuries, matched for sex, age, body mass index (BMI), sport, and occupational weightbearing activities. Included patients were 20-65 years with ultrasonographic-verified PF or midsubstance AT. Foot posture was assessed using Foot Posture Index (FPI) classifying the feet into 3 categories: FPI 0-5 normal foot, 6-12 hyperpronated, <0 hypopronated. Ankle dorsiflexion was measured with a goniometer in weightbearing with straight and bent knee. Abnormal foot posture was associated with an increased risk for sustaining both AT (odds ratio [OR] 3.4-4.1) and PF (OR 3.2-3.8). Hyperpronation being the major reason for this association with ORs 5.4-5.5 compared with hypopronation with ORs 2.6-2.9. However, decreased dorsiflexion was not a risk factor: instead, there was an increased ankle dorsiflexion in patients with AT or PF compared with their control groups. Comparison between PF and AT patients demonstrated that PF affected mostly women, and AT mostly men, PF patients were 2.4 years (CI 0.2-4.5) younger, and had 25% more occupational weightbearing than AT patients. However, no differences in BMI or weightbearing physical activity was demonstrated. Hypopronation and hyperpronation but not limited ankle dorsiflexion was associated with increased risk for AT or PF.

Tibia-first, gap-balanced patient-specific alignment restores bony phenotypes and joint line obliquity in a great majority of varus and straight knees and normalises valgus and severe varus deformities.

The present study focuses on testing the capability of a restricted tibia-first, gap-balanced patient-specific alignment technique (PSA) to restore bony morphology and phenotypes. Three-hundred and sixty-seven patients were treated with navigated total knee arthroplastyand tibia-first gap-balanced PSA technique. Boundaries for medial proximal tibial angle were 86°-92°, mechanical lateral distal femoral angle 86°-92°, and hip-knee-ankle angle175°-183°. Knees were classified by coronal plane alignment of the knee (CPAK), with subsequent analyses comparing pre- and postoperative distributions. Phenotype classification within CPAK groups assessed pre- and postoperative distributions. Preoperatively, the largest CPAK group was type II (30.8%), followed by type I (20.5%) and type V (17.8%). Postoperatively, type II remained the largest group (39%), followed by type V (30%). All groups with varus/valgus deformities (I, III, IV and VI) became smaller. While in straight legs (II, IV), the CPAK was restored in more than 70%-75%, in varus groups (I, IV) in 40%-50%and in valgus (III and VI) in 5%-18%. The joint line obliquity remained the same in the majority of knees (straight >75%; varus 63%-80%; valgus VI 95%), with the exception of CPAK III (40%). The phenotype analysis showed for straight legs a phenotype restoration of 85%, for varus 94% and for valgus 37%. Joint line convergence anglewas reduced significantly in all groups from 1.8°-4.3° preoperatively to 0.6°-1.2° postoperatively. PSA restores bony phenotypes and joint line obliquity in the majority of straight and varus knees, while most of the valgus and extreme varus knees are normalised. Level III, retrospective cohort study.

Femoral Tunnel Position in Anatomical Double-bundle ACL Reconstruction is not Affected by Blumensaat's Line Morphology.

The aim of this study was to reveal the influence of the morphological variations of the Blumensaat's line on anteromedial (AM) and posterolateral (PL) femoral tunnel position in anatomical double-bundle anterior cruciate ligament (ACL) reconstruction.Fifty-three subjects undergoing anatomical double-bundle ACL reconstruction were included (29 female, 24 male; median age 27.4 years; range: 14-50 years). Using an inside-out transportal technique, the PL tunnel position was made on a line drawn vertically from the bottommost point of the lateral condyle at 90 degrees of knee flexion, spanning a distance of 5 to 8 mm, to the edge of the joint cartilage. AM tunnel position was made 2 mm distal to the PL tunnel position. Following Iriuchishima's classification, the morphology of the Blumensaat's line was classified into straight and hill (large and small) types. Femoral tunnel position was determined using the quadrant method. A Mann-Whitney U test was performed to compare straight and hill type knees according to AM and PL femoral tunnel position.There were 18 straight and 35 hill type knees (13 small and 22 large hill). AM and PL femoral tunnel position in straight type knees were 21.7 ± 7.0 and 33.6 ± 10.5% in the shallow-deep direction, and 42.1 ± 11.1 and 72.1 ± 8.5% in the high-low direction, respectively. In hill type knees, AM and PL femoral tunnel position were 21.3 ± 5.8 and 36.9 ± 7.1% in the shallow-deep direction, and 44.6 ± 10.7 and 72.1 ± 9.7% in the high-low direction, respectively. No significant difference in AM or PL femoral tunnel position was detected between straight and hill type knees.AM and PL femoral tunnel position in anatomical double-bundle ACL reconstruction was not affected by the morphological variations of the Blumensaat's line. Surgeons do not need to consider Blumensaat's line morphology if AM and PL femoral tunnel position is targeted at the bottommost point of the lateral condyle. This was a level of evidence III study.

The impact of rule updates on the performance of racewalkers and the classification of countries: An analysis at the Olympic Games

Numerous controversies arose over the judgment of the racewalking events, and the rules were amended more than once. Before 1995, the rule required constant touch with the ground, and the need for a straight knee was only applied in the upright vertical posture. While, after 1995, the rule that applies today was published, which included two obvious changes. One related to maintaining a constantly straight knee through the first half of the stride, and the other to maintaining contact as seen by the human eye. This study aimed to investigate the impact of the last three modifications in racewalking rules on elite athletes' performance, athletes' eligibility, and nations' classification. Also, we investigated the regression between performance times of 20, and 50 km events and explanatory variables (BMI, and age). We collected data of 310 racewalkers from Olympic Games records (men) in 20km and 50km between 1956 and 2016. This period was divided into three stages according to the racewalking rules updates: Stage A (from 1996 to 2016), Stage B (from 1976 to 1992), and Stage C (from 1956 to 1972). There was a significant difference between all stages favoring stage A for Athlete’s Performance. Stage A has the highest speeds (4.06±.23m/sec) for 20km with large ES (η2=.54, p=.000), and (3.71±.06m/sec) for 50km with large ES (η2=.769, p=.000) compared to others. The participants had the efficiency and the ability to finish the race with the least percentage of withdrawals under the current rule compared to other rules. Some countries emerged on the scene, i.e. China, Poland and Ecuador, and others disappeared under the current rule; while the regression model's results revealed a substantial link between time and explanatory parameters where (BConstant=58.219, P.000) for 20km and (BConstant=164.744, P.000) for 50km. Results proved that the elite walkers, the youngest and lowest in BMI, are the fastest and most efficient walkers under the current rule.

Assessing the Sensitivity of the Ratio Method in Identifying the Flexion-Relaxation Phenomenon in People With Non-specific Low Back Pain and Healthy People

Background and Aims There are different methods for quantifying the flexion-relaxation phenomenon (FRP). However, there is little standardization for them. This study aimes to evaluate the sensitivity of the ratio method in identifying the FRP in people with non-specific low back pain (LBP) and healthy people. Methods In this study,10 patients with nonspecific LBP and 10 healthy people participated voluntarily. They performed a trunk flexion with a straight knee. Each trunk flexion was done in four modes: (1) standing in the starting position, (2) trunk flexion at a fixed speed (using a metronome), (3) full flexion, and (4) trunk extension to the standing position. Each mode took 5 seconds and was performed 3 times. Then, the FRP was investigated using the ratio method as well as the visual inspection method. Results The sensitivity of all ratios in identifying the FRP in healthy people was 100%, except for the third ratio (the root mean square of EMG activity in a standing position divided by the root mean square in flexion mode), which was 60%. In the LBP group, the sensitivity of the first ratio was 70%; for the second ratio, it was 80%; for the third ratio, 40%; for the fourth ratio, 50%; for the fifth mode (the root mean square in extension mode divided by the root mean square in full flexion mode), 40%; and for the sixth mode, 50%. Conclusion All ratios (except for the second ratio) are valid for identifying the FRP in healthy people, but caution should be taken in using the ratio method for people with LBP; only the second ratio (maximum EMG activity in the extension mode divided by the average EMG activity in the full flexion mode) should be used for these individuals.

Independent of the preoperative coronal deformity, adjusted mechanical alignment leads in a high percentage to non-anatomical tibial and femoral bone cuts.

The technique of adjusted mechanical alignment (AMA) in total knee arthroplasty (TKA) has been described to achieve alignment and balancing goals in varus knees in a high percentage, albeit at the price of non-anatomical bone cuts. The purpose of this study was to analyze (1) whether AMA achieves similar alignment and balancing results in different types of deformity and (2) whether they can be achieved without altering the native anatomy. A series of 1000 patients with hip-knee-ankle (HKA) angles from 165° to 195° were analyzed. All patients were operated using AMA technique. According to the preoperative HKA angle, three groups of knee phenotypes (varus, straight, valgus) were defined. The bone cuts were analyzed for being anatomic (< 2mm deviation of individual joint surface) or non-anatomic (> 4mm deviation of individual joint surface). AMA reached the goals for postoperative HKA in over 93% in every group (varus: 636 cases, 94%, straight: 191 cases, 98%, valgus: 123 cases, 98%). In 0° extension, the gaps were balanced in varus knees in 654 cases (96%), in straight knees in 189 cases (97%) and in valgus knees in 117 cases (94%). A balanced flexion gap was found in a similar number of cases (varus: 657 cases, 97%, straight: 191 cases, 98%, valgus: 119 cases, 95%). In the varus group, non-anatomical cuts were performed at the medial tibia (89%) and the lateral posterior femur (59%). The straight group showed similar values and distribution for non-anatomical cuts (medial tibia: 73%; lateral posterior femur 58%). Valgus knees showed a different distribution of values, being non-anatomical at the lateral tibia (74%), distal lateral femur (67%) and posterior lateral femur (43%). In all knee phenotypes, the AMA goals were achieved in a high percentage by altering the patients' native anatomy. In varus knees, the alignment was corrected by non-anatomical cuts at the medial tibia, and in valgus knees at the lateral tibia and the lateral distal femur. All phenotypes showed non-anatomical resections on the posterior lateral condyle in approximately 50% of cases. III.

Elevated In Vivo ACL Strain Is Associated With a Straight Knee in Both the Sagittal and the Coronal Planes

Background: Noncontact anterior cruciate ligament (ACL) injuries typically occur during deceleration movements such as landing or cutting. However, conflicting data have left the kinematic mechanisms leading to these injuries unclear. Quantifying the influence of sagittal and coronal plane knee kinematics on in vivo ACL strain may help to elucidate noncontact ACL injury mechanisms. Purpose/Hypothesis: The purpose of this study was to measure in vivo sagittal and coronal plane knee kinematics and ACL strain during a single-leg jump. We hypothesized that ACL strain would be modulated primarily by motion in the sagittal plane and that limited coronal plane motion would be measured during this activity. Study Design: Descriptive laboratory study. Methods: Seventeen healthy participants (8 male/9 female) underwent magnetic resonance imaging (MRI) followed by high-speed biplanar radiography, obtained as participants performed a single-leg jump. Three-dimensional models of the femur, tibia, and associated ACL attachment site footprints were created from the MRIs and registered to the radiographs to reproduce the position of the knee during the jump. ACL strain, knee flexion/extension angles, and varus/valgus angles were measured throughout the jump. Spearman rank correlations were used to assess relationships between mean ACL strain and kinematic variables. Results: Mean ACL strain increased with decreasing knee flexion angle (ρ = −0.3; P = .002), and local maxima in ACL strain occurred with the knee in a straight position in both the sagittal and the coronal planes. In addition, limited coronal plane motion (varus/valgus angle) was measured during this activity (mean ± SD, −0.5°± 0.3°). Furthermore, we did not detect a statistically significant relationship between ACL strain and varus/valgus angle (ρ = −0.01; P = .9). Conclusion: ACL strain was maximized when the knee was in a straight position in both the sagittal and coronal planes. Participants remained in <1° of varus/valgus position on average throughout the jump. As a ligament under elevated strain is more vulnerable to injury, landing on a straight knee may be an important risk factor for ACL rupture. Clinical Relevance: These data may improve understanding of risk factors for noncontact ACL injury, which may be useful in designing ACL injury prevention programs.

EFEITO DO TREINAMENTO DE EQUILÍBRIO SOBRE A APTIDÃO FÍSICA DOS MARATONISTAS

ABSTRACT Introduction: As a comprehensive sport, Marathon presents high demands concerning the athletes’ comprehensive capacity. Objective: This paper explores to what extent balance skill training can effectively contribute to improving physical fitness for marathon runners. Methods: 120 marathon runners were selected for the pilot experiment. The experimental group received balance training, while the control group underwent no intervention. Results: In the experimental group, the time with eyes closed and feet apart increased from 33.559 ± 15.8570 to 37.203 ± 15.5865s, the time spent in the T-shaped run from 10.144 ± 0.5063s to 9.908 ± 0.5225s, the time spent in the standing long jump from 2.831 ± 0.2648m to 3.058 ± 0.3183m, and the time spent in the T-shaped run from 55.544 ± 2.2581 to 60.845 ± 2.4367 times/min. The total FMS score changed from 14.618 ± 0.9392 to 18.481 ± 1.3909. Shoulder flexibility increased from 2.777 ± 0.4756 to 2.917 ± 0.2994, and active straight knee raise changed from 2.306 ± 0.4692 to 2.803 ± 0.403. Conclusion: Daily balance training can be added to usual marathon training to improve the fitness of its athletes. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

The Predicted Position of the Knee Near the Time of ACL Rupture Is Similar Between 2 Commonly Observed Patterns of Bone Bruising on MRI

Background: Bone bruises observed on magnetic resonance imaging (MRI) can provide insight into the mechanisms of noncontact anterior cruciate ligament (ACL) injury. However, it remains unclear whether the position of the knee near the time of injury differs between patients evaluated with different patterns of bone bruising, particularly with regard to valgus angles. Hypothesis: The position of the knee near the time of injury is similar between patients evaluated with 2 commonly occurring patterns of bone bruising. Study Design: Descriptive laboratory study. Methods: Clinical T2- and T1-weighted MRI scans obtained within 6 weeks of noncontact ACL rupture were reviewed. Patients had either 3 (n = 20) or 4 (n = 30) bone bruises. Patients in the 4–bone bruise group had bruising of the medial and lateral compartments of the femur and tibia, whereas patients in the 3–bone bruise group did not have a bruise on the medial femoral condyle. The outer contours of the bones and associated bruises were segmented from the MRI scans and used to create 3-dimensional surface models. For each patient, the position of the knee near the time of injury was predicted by moving the tibial model relative to the femoral model to maximize the overlap of the tibiofemoral bone bruises. Logistic regressions (adjusted for sex, age, and presence of medial collateral ligament injury) were used to assess relationships between predicted injury position (quantified in terms of knee flexion angle, valgus angle, internal rotation angle, and anterior tibial translation) and bone bruise group. Results: The predicted injury position for patients in both groups involved a flexion angle <20°, anterior translation >20 mm, valgus angle <10°, and internal rotation angle <10°. The injury position for the 3–bone bruise group involved less flexion (odds ratio [OR], 0.914; 95% CI, 0.846-0.987; P = .02) and internal rotation (OR, 0.832; 95% CI, 0.739-0.937; P = .002) as compared with patients with 4 bone bruises. Conclusion: The predicted position of injury for patients displaying both 3 and 4 bone bruises involved substantial anterior tibial translation (>20 mm), with the knee in a straight position in both the sagittal (<20°) and the coronal (<10°) planes. Clinical Relevance: Landing on a straight knee with subsequent anterior tibial translation is a potential mechanism of noncontact ACL injury.

TREINO FÍSICO GUIADO POR SISTEMA DE MOVIMENTO FUNCIONAL NA REABILITAÇÃO DE LESÕES ESPORTIVAS

ABSTRACT Introduction: The Functional Movement Screen is a standardized tool that proposes the evaluation of movement and body stability. That information can assist in decision-making for accurate and focused training programs. However, few studies address its use in the rehabilitation of table tennis players. Objective: Perform an experimental study on the physical training guided effect by the Functional Movement System method in sports injuries rehabilitation. Methods: Ten table tennis players, aged 18 to 24 years, with knee assessment scale scores between 6 and 8 points and skill level II in the sport were selected. The individuals underwent three months of physical training guided adequately by the screening results. SPSS20 software was used to analyze body composition indices, including thigh and calf circumferences. Lower limb torque was also compared. Results: There was no change in weight or BMI; however, a difference was noted in the thigh (from52.61cm to 53.26cm) and calf (from 32.34cm to 33.16cm) circumference. Statistical difference was noted in squat, straight knee raise, hurdles, and flexion tests (P&lt;0.001). Conclusion: The Functional Movement System proved to be effective as a screening and assessment tool for rehabilitation in knee injuries of table tennis players. Evidence Level II; Therapeutic Studies - Investigating the result.

Cognitive therapeutic exercise in early proprioception recovery after knee osteoarthritis surgery.

ObjectiveThis research aims to explore the therapeutic effect of cognitive therapeutic exercise (CTE) in proprioception recovery after knee osteoarthritis (KOA) surgery.MethodsIn total, thirty-seven patients recovering from KOA surgery (including 27 patients who had undergone high-tibial osteotomy (HTO) procedure and 10 patients who had received total knee arthroplasty (TKA) treatment were randomly assigned to two groups: 18 patients in the CTE group and 19 patients for the control group (non-CTE). Patients in the CTE group received proprioceptive training as cognitive therapy to facilitate proprioception recovery for up to 4 weeks: 5 days a week and two 10-min sessions a day. Except for cognitive therapeutic exercise, the NCTE group and CTE group had the same treatment protocols. All the interventions began with permission from the surgeon-in-charge. In this research, we applied the joint repositioning training or joint-matching tasks, which is part of the proprioceptive training as a measurement for a proprioceptive training result where patients moved their knee joint from 0° (completely straight knee joint) to produce a presented joint angle, such as 30, 60, and 90° of flexion. Joint-matching task results were recorded before the treatment, at 2 and 4 weeks, postoperatively. The absolute difference between the results of these exercises and the knee flexion angle targets will be measured at each test—pre-rehabilitation (Pre-Reha), 2 weeks post-rehabilitation (2 weeks post-Reha), and 4 weeks post-rehabilitation (4 weeks post-Reha).ResultsThe absolute difference in the CTE group was significantly smaller than that of the control group after 4 weeks of treatment (P < 0.05). After 2 weeks of cognitive therapeutic exercise, the absolute difference between patients' exercises of joint repositioning and the target angle of 30° in the CTE group was smaller than that of the NCTE group (P < 0.01). After 4 weeks of therapy, the joint position sense (JPS) among patients who received cognitive therapeutic exercise when performing joint repositioning at angles of 30 and 60° were better improved than those without receiving proprioceptive training with the absolute difference smaller than those of the control group (P < 0.05).ConclusionThe joint reposition training provided for the CTE group is a painless proprioceptive training practice. This method is simple and effective, making it easy for patients to understand the purpose of training and improve patient engagement. The research showed that after 4 weeks of rehabilitation and physical training, the proprioception sense of both the NCTE and CTE groups improved significantly, and the efficacy of proprioceptive training in the CTE group was better than that of the NCTE group, which provided a new approach to the early proprioception recovery of a patient with KOA after surgery.

The effects of knee flexion on muscle activation and performance during chin-up exercise

Background and Study Aim. Chin-up is an exercise that is done to improve the strength, muscular endurance and size of the upper back and arm muscles. There are many ways to perform chin-up exercises including by performing it with different forms of knee flexion. This study aims to examine the effects of knee flexion on muscle activation and performance during chin-up exercise.&#x0D; Material and Methods. A total of twenty-one healthy trained male (age 20-25 years old) were recruited and were instructed to perform chin-up exercises in three knee conditions: i) knee fully flexed, ii) partial knee flexed, and iii) straight knee. Chin-up performance was measured by the number of repetitions performed in three sets. Muscle activation was measured using EMG and taken from latissimus dorsi (LD), posterior deltoid (PD), and biceps brachii (BB) during both concentric and eccentric phase. One-way repeated measure Analysis of Variances (ANOVA) were conducted to compare the muscle activation and number of repetitions performed across the three variation of chin-up exercise.&#x0D; Results. Findings showed that during the concentric phase, BB recorded higher muscle activation during straight knee compared to knee fully flexed and partial knee flexed, p &lt; .05. In addition, chin-up performance during straight knee and partial knee flexed were better than knee fully flexed, p &lt; .05.&#x0D; Conclusions. The results of this study demonstrated the importance to consider techniques manipulation during exercises due to its effects on acute responses as shown by number of repetitions and muscle activation in this study that might also affect the long-term outcomes.

Effects of Various Body Positions on Arterial Stiffness as Assessed by Pulse Wave Velocity

BackgroundStandard measurements of arterial stiffness via pulse wave velocity (PWV) are conducted with participants in the supine position. When participants cannot tolerate supine position for prolonged procedure time (e.g., low back pain), accommodations may be made to tilt the bed up or bend the knees (i.e., Fowler’s positions). Moreover, a new testing device (Vicorder) that uses neck oscillometric cuff requires upper body tilt to avoid jugular vein interference on the recorded carotid pulse. Accordingly, this study aimed to investigate the effect of varying body positions on arterial stiffness measured via PWV.METHODSA total of 70 adults (43 women) varying widely in age (19‐66 years old), race/ethnicity (41% non‐white), and medical conditions were studied. Both carotid‐femoral PWV (cfPWV) and brachial‐ankle PWV (baPWV) were measured using two different testing devices (Omron vp1000plus and Vicorder) with participants in the reference supine (0º) position, 10º, 20º, 30º, and 40º upper body tilted‐up positions with and without knee flexion. The presence of jugular vein interference was documented visually on the oscillometric arterial waveforms at each body angle.RESULTSBoth cfPWV and baPWV measured at 10º upper body tilt‐up position were not significantly different from those assessed at the reference supine (0º) position. Upper body angle of 20º or greater produced PWVs that were significantly and gradually elevated (p&lt;0.01). The magnitude of elevations in cfPWV were 7% (95% CI [6‐11%]) at 20º and 15% (95% CI [11‐18%]) at 40º while the elevations in baPWV were 8% (95% CI [6‐10%]) at 10º and 33% (95% CI [30‐36%]) at 40º compared with the supine (0º) position. Knee flexion did not alter cfPWV compared with straight knees whereas knee flexion decreased baPWV at the same upper body angle (p&lt;0.05). Jugular vein interference in the Vicorder device appeared on 78% of participants in the supine (0º) position and gradually decreased as the upper body angle increased, resulting in 7% of the participants at 30º angle. The appearance of Jugular vein contamination was not affected by knee flexion.CONCLUSIONArterial stiffness as assessed by cfPWV and baPWV increased gradually and significantly by the use of semi‐Fowler position of ≥20º whereas bending knees at each angle decreased baPWV, but did not appear to influence cfPWV. Our present findings highlight the difficulty in comparing two different devices that are supposed to reflect the same arterial property.

The neuromuscular responses in patients with Parkinson\u2019s disease under different conditions during whole-body vibration training

BackgroundWhole-body vibration (WBV) training can provoke reactive muscle response and thus exert beneficial effects in various neurological patients. This study aimed to investigate the muscles activation and acceleration transmissibility of the lower extremity to try to understand the neuromuscular control in the Parkinson’s disease (PD) patients under different conditions of the WBV training, including position and frequency.MethodsSixteen PD patients and sixteen controls were enrolled. Each of them would receive two WBV training sessions with 3 and 20 Hz mechanical vibration in separated days. In each session, they were asked to stand on the WBV machine with straight and then bended knee joint positions, while the vibration stimulation was delivered or not. The electromyographic (EMG) signals and the segmental acceleration from the lower extremity were recorded and processed. The amplitude, co-contraction indexes (CCI), and normalized median frequency slope (NMFS) from the EMG signals, and the acceleration transmissibility were calculated.ResultsThe results showed larger rectus femoris (RF) amplitudes under 3 Hz vibration than those in 20 Hz and no vibration conditions; larger tibialis anterior (TA) in 20 Hz than in no vibration; larger gastrocnemius (GAS) in 20 Hz than in 3 Hz and no vibration. These results indicated that different vibration frequencies mainly induced reactive responses in different muscles, by showing higher activation of the knee extensors in 3 Hz and of the lower leg muscles in 20 Hz condition, respectively. Comparing between groups, the PD patients reacted to the WBV stimulation by showing larger muscle activations in hamstring (HAM), TA and GAS, and smaller CCI in thigh than those in the controls. In bended knee, it demonstrated a higher RF amplitude and a steeper NMFS but smaller HAM activations than in straight knee position. The higher acceleration transmissibility was found in the control group, in the straight knee position and in the 3 Hz vibration conditions.ConclusionThe PD patients demonstrated altered neuromuscular control compared with the controls in responding to the WBV stimulations, with generally higher EMG amplitude of lower extremity muscles. For designing WBV strengthening protocol in the PD population, the 3 Hz with straight or flexed knee protocol was recommended to recruit more thigh muscles; the bended knee position with 20 Hz vibration was for the shank muscles.

Differences in Pivot Leg Kinematics and Electromyography Activation in Various Round House Kicking Heights.

The round house kick (RHK) is a common technique in taekwondo (TKD). The kicking action originates from the dynamic stability of the pivot leg. However, some knee injuries are caused by more difficult kicking strategies, such as kicks to the opponent's head. This study analyses the effects on TKD players in the lower extremity kinematic and neuromuscular reactions from different kicking heights. This study recruited 12 TKD players (age=20.3 ± 1.3 years, height = 1.72 ± 0.09 m, mass = 62.17 ± 9.45 kg) with no previous lower extremity ligament injuries. All athletes randomly performed 3 RHK at different heights (head, chest, and abdomen), repeating each kick 5 times. During the RHK action, the kinematics and muscle activations of the pivot leg were collected using six high-speed cameras and electromyography devices. The results found that during the RHK return period a high kicking position demonstrated larger knee valgus with the straight knee, and more hamstring activation on the pivot leg. The RHK pivot foot for TKD players encountered more risk of injury from high target kicking. The hamstring muscle played an important stabilizing role. It is recommended that sports medicine clinicians or sports coaches use this information to provide further protective injury prevention strategies.

Comparison of Electromyographic Activity During Hip Extension Exercises Under Gravitational or Inertial Loading Conditions.

Hamstring injury prevention programs include strengthening, especially eccentric exercises using both gravitational and inertial loading. Inertial exercises are characterized by eccentric contractions of high intensity and velocity. This study aimed to analyze the muscular activation of the biceps femoris (BF), semitendinosus (ST), gluteus maximus (GM), and gracilis (GC) muscles during hip extension (HE) exercises performed under both gravitational and inertial loading conditions. Inertial training would generate a greater activation of HE muscles than gravitational training. Cross-sectional study. Level 4. Fifteen resistance-trained men performed the unilateral straight knee bridge (SKB), 45° of HE, and stiff-leg deadlift (SDL) exercises under gravitational and inertial loading conditions. Concentric and eccentric phases were identified with a linear encoder. Differences between load types, exercises, and their interaction were examined to establish the electromyographic (EMG) activity of each muscle and BF/ST ratio. In the concentric phase, inertial loading showed a higher normalized EMG than gravitational loading for BF, ST, and GM. SKB and HE activated BF and ST between 9.6% and 24.3% more than SDL. In the eccentric phase, the inertial modality achieved greater GM activation than the gravitational form (18.1%). BF activation was increased with HE and SKB as compared with SDL (24.4% and 16.4%, respectively), while ST activation was likewise enhanced with HE as compared with SDL (15.1%). Inertial training is more effective than gravitational training for the concentric activation of the hamstring muscles while SDL showed lower hamstring activation than HE and SKB. Therefore, HE and SKB with inertial loading should be taken into account in hamstring training programs. Inertial training is more effective than gravitational training for the concentric activation of the hamstring muscles. HE and SKB with inertial loading should be taken into account in hamstring training programs.

The Motor Function Evaluation of College Students' Physical Activity State From the Perspective of Educational Psychology.

College students have taken part in less and less physical activities as a result of the common static lifestyle in recent years, lowering the level of motor function. This phenomenon has been a source of concern for schools and the government, and it is necessary to take corresponding measures to change it. The general motor function level of Chinese college students is explored first based on artificial intelligence and the human–computer interaction technology. The Physical Activity Questionnaire for College Students is compiled by referring to the International Physical Activity Questionnaire, and 561 students from colleges in Tianjin province are assessed based on the functional movement screen (FMS). Spearman correlation and multivariate regression analysis (MRA) are used to analyze the correlation between the motor function and physical activity status. In terms of lunch break frequency, the proportion of students having one to two lunch breaks in a week is the highest (54.15%); in terms of the frequency of doing moderate physical exercise, the proportion of students doing moderate physical exercise for 1–2 days in a week is the highest (50.61%); in terms of the frequency of doing heavy physical exercise, the proportion of students doing heavy exercise for 1–2 days in a week is the highest (47.26%); in terms of the sedentary time, the proportion of students with sedentary time more than 5 h in a day is the highest (40.61%); in terms of eye use time, the proportion of students with 8–10 h eye use time in a day is the highest (43.61%). Besides, in terms of the FMS score, the proportion of students with 13–15 FMS is the highest (48.46%). The hurdle step (21.03%), straight knee lift (22.52%), and body rotation stability (18.31%) have a relatively low proportion among the three-point items. There is a positive correlation between motor function score with the time of moderate exercise and the time of heavy exercise (P < 0.05). College students generally have insufficient rest time, long eye use time, and long sitting time, leading to a low level of motor function, manifested by an asymmetry between both sides of the body and poor trunk stability. It is recommended to add hurdling steps, straight knee lifts, and body rotation stability tests to college physical education courses.

Pedal Musculovenous Pump Activation Effectively Counteracts Negative Impact of Knee Flexion on Human Popliteal Venous Flow.

Knee scooters are commonly used for mobility instead of other devices. However, passive popliteal venous flow impedance has been observed with knee scooter usage ostensibly as a result of deep knee flexion. This study aimed to characterize the magnitude of impact knee flexion has on popliteal venous flow in relation to the degree of knee flexion when walking boot immobilized. Furthermore, the countervailing effect of standardized pedal musculovenous pump (PMP) activation was observed. Popliteal venous diameter and flow metrics were assessed with venous ultrasonography in 24 healthy individuals. Straight leg, crutch, and knee scooter positioning while wearing a walking boot and non-weight-bearing were compared. Flow was assessed with muscles at rest and with PMP activation. Of 24 participants, 16 (67%) were female. Twelve limbs (50%) were right sided. The mean age was 21.9 (SD = 3.0) years, and the mean body mass index was 21.9 (SD 1.9) kg/m2. Observer consistencies were excellent (intraclass correlation range = 0.93 to 0.99). No significant differences in mean vessel diameter, time-averaged mean velocity, and total volume flow occurred (all P > .01). Corresponding knee flexion effect sizes were small (range = -0.04 to -0.26). A significant decrease (-24%) in active median time-averaged peak velocity occurred between upright and crutch positions (20.89 vs 15.92 cm/s; P < .001) with a medium effect size (-0.51). PMP activation increased all flow parameters (all P < .001), and effect sizes were comparatively larger (>0.6) across all knee flexion positions.Clinical Significance: Knee flexion has a small to medium impact on popliteal venous return in healthy patients. Active toe motion effectively counters the negative effects of gravity and knee flexion when the ankle is immobilized.Levels of Evidence: Therapeutic, Level IV.

Evaluation of the effect of patient position in the management of chronic heart failure patients presenting with dyspnea

Background/Aim: One of the pathomechanisms of congestive heart failure is inadequate cardiac load, and one of the physiological ways to reduce cardiac load is to decrease venous return. Based on this mechanism, we aimed to reduce venous return and alleviate cardiac load in patients by drooping their legs. In this study, we aimed to evaluate the impact of leg position on patients' comfort and treatment, emphasize that patient position is valuable enough to be included in the treatment algorithm, and determine the effects of the patient sitting with legs hanging down position in an armchair (sitting position), or upright with the straight knees position on a stretcher with the stretcher’s head at 90°C (high Fowler's position) on the patient's perception of dyspnea in chronic heart failure (CHF). Methods: Patients over 18 years of age, followed-up with CHF diagnosis who presented to the emergency department (ED) with dyspnea were included in this case control study. The participants were divided into high Fowler's and sitting groups. According to the Visual Analog Scale (VAS) scoring, patients were asked to point to the severity of dyspnea. Patients’ vital signs, 30-day mortality, and VAS scores were recorded at the 0th, 15th, 30th, and 60th minutes. Results: A total of seventy-four patients were included in the study. Thirty-eight patients in the high Fowler’s group, and thirty-six patients in the sitting group were treated. VAS started to decrease significantly at 15 minutes in sitting position. Although baseline VAS scores were higher at sitting than at the high Fowler’s position, the end of the 60th minute VAS scores and respiratory rate were significantly lower in the sitting group (P=0.016, and P=0.008, respectively). The mortality rate was significantly higher in the high Fowler’s group (P=0.028). Conclusions: We concluded that patient position plays a vital role in patients' perception of dyspnea and mortality in the acute treatment of CHF patients presenting with dyspnea. Perception of dyspnea disappears earlier, and mortality is lower in the sitting position.

Validity of an inertial system for measuring velocity, force, and power during hamstring exercises performed on a flywheel resistance training device

BackgroundInertial hamstring exercises promote functional changes leading to lower rates of hamstring injuries. However, variable training measurement systems have not been specifically validated for hamstring exercises. Accordingly, this study aimed to evaluate the validity of the Inertial Measurement System (IMS) to measure the velocity, force, and power during the performance of different hamstring exercises on a flywheel resistance training device.MethodsFifteen males (average age: 22.4 ± 2.5 years; body mass: 77.3 ± 9.8 kg; height: 179.5 ± 7.4 cm; weekly physical activity: 434.0 ± 169.2 min; years of strength training: 4.3 ± 2.2 years) performed the bilateral stiff-leg deadlift (SDL), 45° hip extension (HE), and unilateral straight knee bridge (SKB) in two sessions (familiarization and evaluation) with a 1-week interval between them. The velocity, force, and power (average and peak values) in the concentric and eccentric phases for each of the exercises were recorded simultaneously with IMS and MuscleLab.ResultsConsistency between IMS and MuscleLab was good to excellent for all variables, with r ranges from 0.824 to 0.966 in SDL, from 0.822 to 0.971 in HE, and from 0.806 to 0.969 in SKB. Acceptable levels of agreement between devices were observed in general for all exercises, the “bias” ranging from 1.1% to 13.2%. Although MuscleLab showed higher values than IMS for peak velocity, force and power values, the effect size was only relevant for 5 of the 36 parameters. IMS is a new and valid system to monitor inertial hamstring exercises on a new flywheel device. In this way, IMS could have potential practical applications for any professional or athlete who wants to monitor inertial hamstring exercises.