Reliability and Differences of Jump Kinetics Related to Different Load in College Male Athletes

The purpose of this study was to explore reliability and differences of jump kinetics related to different training load in college male athletes. The subjects were required to perform countermovement jump (CMJ) and loaded countermovement jump (LCMJ-0%, LCMJ-20% and LCMJ-80% of one-repetition maximum squat) three times for each load which were recorded by a force plate. One-way repeated measures ANOVA and the LSD post hoc method were employed to evaluate the results. The results reveled that jump kinetics-related parameters increased/decreased by the load. Compared with the loading jumps, the CMJ incorporate with an arm swing directly led to an increase in eccentric contraction duration during jumping. Most of the jump mechanical parameters under substantially different load conditions fall within the good to excellent reliability. It appears that the CMJ and CMJ with extra load were reliable in explore the kinetics related parameters. Keywords: countermovement jump, one-repetition maximum, arm swing, eccentric contraction

PSX-B-10 Effect of undigested neutral detergent fiber concentration and forage inclusion rate on ruminal pH, reticular motility, and total tract permeability for finishing beef heifers

This study evaluated the effects of undigested neutral detergent fiber (uNDF) concentration and forage inclusion (FI) rate on dry matter (DM) intake, ruminal pH, reticular contractions, and gastrointestinal permeability for finishing beef cattle. Five ruminally cannulated Hereford′Simmental heifers (699±69.1 kg) were used in an incomplete 6×6 Latin square (26-d periods) with a 2×3 factorial treatment arrangement. Barley grain-based diets were formulated using barley silage or wheat straw to provide low or high uNDF (7.1 vs. 8.5% DM) with forage proportions of 5, 10, or 15% of dietary DM. Dry matter intake (P ≥ 0.10) and eating time (P ≥ 0.13) were not affected by uNDF, FI, or uNDF′FI. With low uNDF diets, increasing FI numerically (P = 0.02) increased rumination time (min/d); while, with high uNDF diets, rumination time increased with 5 to 10% FI, but not thereafter (P = 0.03). Mean ruminal pH was not affected by uNDF (6.17 vs. 6.19; P = 0.08), but increased with increasing FI (6.04b, 6.23a, and 6.28a; P = 0.02). Duration of ruminal pH < 5.5 was not affected by uNDF but tended (P = 0.07) to be reduced with increasing FI. High uNDF diet tended to increase the frequency of reticular contractions (1.43 vs. 1.51 contractions/min; P = 0.07) but decreased the contraction duration (13.2 vs. 14.1 sec; P = 0.04). Increasing FI increased contraction frequency (1.39b, 1.50a, and 1.53a contractions/min; P = 0.03) and tended to reduce contraction duration as forage increased from 5 to 10 and 15% (14.3, 13.1, and 13.6 sec; P = 0.07). Feeding high uNDF decreased (P = 0.05) permeability of the gastrointestinal tract based on the appearance of Cr-EDTA in urine following an intra-ruminal dose. Increasing FI tended to reduce gastrointestinal tract permeability (P = 0.06). Limited interactions indicate that uNDF and FI act independently suggesting that increasing dietary uNDF, without increasing FI rate, can stimulate frequency of reticulo-ruminal contractions and reduce gastrointestinal permeability for finishing cattle.

Individual Adjustment of Contraction Parameters for Effective Swing Assist Using a Pneumatic Artificial Muscle in the Elderly

Leg swing during walking is controlled by hip and knee flexion motions. This study examined the effect of swing assist using a pneumatic artificial muscle (PAM) driver system on hip and knee motions and gait performance in the elderly. The participants consisted of 10 healthy elderly individuals. Two PAMs were attached to each participant’s left hip joint, and a pressure sensor was inserted under the right heel as the trigger. PAM contraction parameters could be controlled through a smartphone, i.e., the delay from trigger to contraction and the contraction duration. These parameters were randomly changed to 0, 100, or 200 ms for the delay and 100, 200, or 300 ms for the contraction. Four combination patterns of delay and contraction duration were observed as the parameter settings for maximizing the hip flexion angle. During walking with the PAM assistance, the hip and knee flexion angles in the swing phase and hip angular excursion of the elderly were significantly increased without altering the gait performance. The findings show that our PAM driver system can realize effective swing assist through changing temporal parameter settings for the PAM contraction in the elderly.

Deep Tendon Reflex: The Tools and Techniques. What Surgical Neurology Residents Should Know

The deep tendon reflex (DTR) is a key component of the neurological examination. However, interpretation of the results is a challenge since there is a lack of knowledge on the important features of reflex responses such as the amount of hammer force, the strength of contraction, duration of the contraction and relaxation. The tools used to elicit the reflexes also play a role in the quality of the reflex contraction. Furthermore, improper execution techniques during the DTR assessment may alter the findings and cloud the true assessment of the nervous system. Therefore, understanding the basic principles and the key features of DTR allows for better interpretation of the reflex responses. This paper discusses the brief history of reflexes, the development of the reflex hammer, and also the key features of a reflex response encompassing the amplitude of force needed to elicit a reflex response, the velocity of contraction, the strength of contraction, and the duration of contraction and relaxation phases. The final section encloses the techniques of eliciting DTR in the upper extremities, trunk, and lower extremities, and the interpretation of these reflexes.

Decrease of urinary bladder contractility in patients with benign prostate hyperplasia

Aim of the study.Estimation of the decrease of urinary bladder contractility in patients with benign prostate hyperplasia (BPH). Patients and methods.In 146 BPH patients (mean age 62,1 0,8) urodynamic investigation including uroflowmetry and pressure-flow study was performed. The results of miction cystometry were evaluated using Shafer nomogram, the emptying idex was calculated as relation of voiding volume to maximal cystometric capacity. Results.56,2% BPH patients showed the decreased detrusor contractility. The results of urinary bladder contractility estimation by Shafer nomogram are dependent on the degree of infravesical obstruction (IVO). The emptying index is not related to the presence and degree of IVO and characterizes the degree of urinary bladder emptying as well as contraction duration. Concomitant lumbar osteochondrosis and diabetes detoriates urinary bladder emptying. Reliable contractility estimation may only be performed based on urodynamic study since basic BPH patients examination is not sufficient. Conclusion.In has to be considered during treatment strategy planning that in many BPH patients low urinary truct disfunction is determined by the decrease of urinary bladder contractility and not by IVO.

The Impact of a Rotating Balance Platform on Leg Neuromuscular Activity in Healthy Young Adults

Balance is a functional activity that must be implemented in every type of rehabilitation for the back and lower extremities’ injury and pathology. With issues in these regions, balance is lessened, requiring exercises that enhance the patient’s stability. Purpose: To determine the impact of activities on a rotating balance platform with tracking tasks for lower limb muscle activation. Method: Twenty-five participants performed seven tasks on a balance board with a fixed middle fulcrum. For each trial, activation of the gastrocnemius and tibialis anterior muscles was recorded using surface electromyography. Upon examination of the EMG data, the following variables were quantified: time to peak muscle activation, time to decay of muscle contraction, and time of muscle contraction duration. Results: A repeated measures ANOVA revealed that TA exhibited significant modifications (P<0.001) with less time to peak, duration, and decay, whereas GA only notably compensated (P<0.001) with shorter duration and decay. Conclusion: For subjects with balance alterations due to slower nerve conduction or muscle weakness in the lower limb, we suggest incorporating activities with rotational movements on the balance board, where muscle activation is challenged due to surface and tracking activities. When endurance is prescribed, front-to-back tasks contribute to prolonged muscle activation. Balance rehabilitation should consider muscle activation timing with tracking tasks for more precise and targeted muscle execution.

Left Ventricular Contraction Duration Is the Most Powerful Predictor of Cardiac Events in LQTS: A Systematic Review and Meta-Analysis

Background: Long-QT syndrome (LQTS) is primarily an electrical disorder characterized by a prolonged myocardial action potential. The delay in cardiac repolarization leads to electromechanical (EM) abnormalities, which adds a diagnostic value for LQTS. Prolonged left ventricular (LV) contraction was identified as a potential risk for arrhythmia. The aim of this meta-analysis was to assess the best predictor of all EM parameters for cardiac events (CEs) in LQTS patients. Methods: We systematically searched all electronic databases up to March 2020, to select studies that assessed the relationship between echocardiographic indices—contraction duration (CD), mechanical dispersion (MD), QRS onset to peak systolic strain (QAoC), and the EM window (EMW); and electrical indices— corrected QT interval (QTC), QTC dispersion, RR interval in relation to CEs in LQTS. This meta-analysis included a total of 1041 patients and 373 controls recruited from 12 studies. Results: The meta-analysis showed that LQTS patients had electrical and mechanical abnormalities as compared to controls—QTC, WMD 72.8; QTC dispersion, WMD 31.7; RR interval, WMD 91.5; CD, WMD 49.2; MD, WMD 15.9; QAoC, WMD 27.8; and EMW, WMD −62.4. These mechanical abnormalities were more profound in symptomatic compared to asymptomatic patients in whom disturbances were already manifest, compared to controls. A CD ≥430 ms had a summary sensitivity (SS) of 71%, specificity of 84%, and diagnostic odds ratio (DOR) >19.5 in predicting CEs. EMW and QTC had a lower accuracy. Conclusions: LQTS is associated with pronounced EM abnormalities, particularly prolonged LV myocardial CD, which is profound in symptomatic patients. These findings highlight the significant role of EM indices like CD in managing LQTS patients.

Effects of a moderate transition from 70 to 90% concentrate diet on early alterations in feeding behavior, rumen environment, reticulorumen motility, and blood acid-base status in beef heifers

The objective of this study was to determine the early responses to a moderate concentrate increase in the diet with regards to various behavioral and physiological responses in cattle. Eight ruminally-cannulated Angus crossbred beef heifers were adapted to a 70% concentrate diet (T70) and then switched to a 90% concentrate diet. Measurements of feeding behavior, ruminal pH and temperature, rumen motility, liquid passage rate, and blood acid-base status were conducted on T70 as well as first (d1 H90) and second (d2 H90) days of high-grain feeding to monitor the beginning of the transition period. Ruminal pH was below 5.6 for longer on both days of H90 compared to T70 and suggested animals experienced subacute ruminal acidosis while switching from T70 to H90. Transitioning did not affect dry matter intake (DMI). Eating rate during meals was reduced on d1 and d2 H90 compared to T70. Ruminal contraction amplitude was reduced on both days of H90 feeding. Contraction duration was reduced on d1 H90, and returned to T70 values by d2 H90. Results indicated that a moderate transition to a finishing diet influenced feeding behavior and reduced rumen motility at the beginning time after transition but did not influence voluntary DMI.

Prolonged left ventricular contraction duration in apical segments as a marker of arrhythmic risk in patients with long QT syndrome

Aims Long QT syndrome (LQTS) is an inherited cardiac ion channelopathy predisposing to life-threatening ventricular arrhythmias and sudden cardiac death. The aim of this study was to investigate left ventricular mechanical abnormalities in LQTS patients and establish a potential role of strain as a marker of arrhythmic risk. Methods and results We included 47 patients with genetically confirmed LQTS (22 LQT1, 20 LQT2, 3 LQT3, and 2 SCN3B) and 25 healthy controls. A history of cardiac events was present in 30 LQTS subjects. Tissue Doppler and speckle tracking echocardiography were performed and contraction duration was measured by radial and longitudinal strain. The radial strain characteristic was subdivided into two planes — the basal and the apical. Left ventricular ejection fraction and global longitudinal strain were normal in LQTS patients. Mean contraction duration was longer in LQTS patients compared with controls in regard to basal radial strain (491 ± 57 vs. 437 ± 55 ms, P &lt; 0.001), apical radial strain (450 ± 53 vs. 407 ± 53 ms, P = 0.002), and longitudinal strain (445 ± 34 vs. 423 ± 43 ms, P = 0.02). Moreover, contraction duration obtained from apical radial strain analysis was longer in symptomatic compared with asymptomatic LQTS mutation carriers (462 ± 49 vs. 429 ± 55 ms, P = 0.024), as well as in subject with mutations other than LQT1 considered to be at higher risk (468 ± 50 vs. 429 ± 49 ms, P = 0.01). Conclusion Myocardial contraction duration is prolonged for both radial and longitudinal directions in LQTS patients. Regional left ventricular function analysis may contribute to risk stratification. Apical radial deformation seems to select subjects at higher risk of arrhythmic events.

P2875Comparison between ejection fraction, global longitudinal strain, mechanical dispersion and delta contraction duration in predicting first and subsequent arrhythmic events in ICD patients

Background According to current guidelines, left ventricular ejection fraction (LVEF) is currently the most important parameter for primary prevention of sudden cardiac death in patients with structural heart disease. Unfortunately, LVEF has low sensitivity in detecting arrhythmic events and presents a significant intra- and inter-operator variability. For these reasons, alternative predictors in patients with structural heart disease are being sought. Among those, speckle-tracking derived parameters such as global longitudinal strain (GLS), mechanical dispersion (MD), and delta contraction duration (DCD) have been proposed as better alternatives. Purpose To assess speckle-tracking derived parameters as predictors of first and subsequent arrhythmic events in implantable cardioverter-defibrillator (ICD) patients with structural heart disease, and to compare their performance with LVEF. Methods Prospective, observational study enrolling all consecutive patients with structural heart disease admitted for an ICD implant. Patients not followed by a home-monitoring system were excluded. 2D speckle-tracking analysis was used to derive GLS, MD, and DCD of all patients at enrolment. Home monitoring was checked weekly in order to detect all ventricular arrhythmias (VA) and ICD therapies. A recurrent-event statistical approach (Prentice, Williams, and Peterson model) was applied in order to evaluate subsequent events after the first ones. Results Two-hundred-and-three patients were consecutively enrolled and followed-up for a median follow-up of 2.2 years. Kaplan-Meier curves showed an increased risk of ATP or shock (Log-rank p=0.003) and VAs (Log-rank p=0.001) associated with lower quartiles of GLS (Figure 1). An impaired GLS was independently associated with an increased risk for the first ICD therapy (HR 1.94; 95% CI 1.30–2.91; p=0.001), and for the first VA (HR 1.42; 95% CI 1.01–1.98; p=0.04). GLS impairment was not significantly associated with an increased risk of recurrent ICD therapies or VAs. LVEF, MD and DCD were not associated with an increased risk of first, second and third ICD therapy or VA. Conclusions Impaired GLS is associated with an increased risk of VAs and appropriate ICD therapies in a consecutive, “real-world”, unselected population of remote-monitored patients with structural heart disease, although it does not seem reliable in predicting further arrhythmic event after the first one. LVEF, MD, and DCD do not predict first or subsequent arrhythmic events in ICD patients with structural heart disease. Acknowledgement/Funding Marche Polytechnic University