Endurance Index Research Articles

Muscle-specific endurance of the trapezius muscles using electrical twitch mechanomyography

Symptoms of fatigue and pain are often reported for the trapezius muscle in the shoulder. The present study evaluated endurance in the trapezius muscles of healthy participants using electric twitch mechanomyography (ETM). Surface electrodes and a tri-axial accelerometer were placed over the left trapezius muscle. Muscles were stimulated for 3 min each at 2 Hz, 4 Hz and 6 Hz. Maintenance of acceleration during muscle twitches was used to calculate an endurance index (EI). Subjects (n = 9) were tested on two separate days to assess reproducibility of the trapezius EI measurements. The endurance measurements were made on the wrist flexor and vastus lateralis muscles for comparison. Near infrared spectroscopy was used to measure muscle oxygenation (HbO2) during the stimulation protocol (n = 8). Mean (SD) EI was 84.9% (8.7%), 63.3% (19.1%) and 41.7% (20.0%) for 2 Hz, 4 Hz and 6 Hz, respectively. The coefficients of variation were 7.4%, 11.3% and 24.0% for 2 Hz, 4 Hz and 6 Hz, respectively. EI values were significantly lower in the trapezius compared to arm and leg muscles (p < 0.05). HbO2 values were unchanged from resting values with electrical stimulation. The EI as measured by ETM may provide a reproducible method of evaluating function in trapezius muscles that is not influenced by oxygen saturation.

Modeling of Running Performances in Humans: Comparison of Power Laws and Critical Speed.

Zinoubi, B, Vandewalle, H, and Driss, T. Modeling of running performances in humans: comparison of power laws and critical speed. J Strength Cond Res 31(7): 1859-1867, 2017-The concepts of power law and critical speed (SCrit) have been applied to the analysis of individual running performances. We have analyzed the results of 2 exceptional runners (Nurmi and Gebrselassie) and 11 physical education students (PESs) who performed 3 exhausting running exercises. Power laws can accurately describe the relationships between exhaustion time (tlim) and distance (Dlim) or speed (S) (Equation is included in full-text article.)in elite runners and PES. However, the validity of the application of power laws must be verified for higher values of tlim in nonelite runners. Exponent γ is close to 1 in elite runners and lower in PESs (from 0.625 to 0.872). The value of SCrit was computed from 2 values of tlim (3-14 minutes; SCrit 3-14) and was expressed as a fraction of maximal aerobic speed (MAS) which was assumed to correspond to the maximal speed that can be sustained over 7 minutes (Equation is included in full-text article.)The individual values of (Equation is included in full-text article.)(0.945 for Gebrselassie, 0.919 for Nurmi, and 0.764 ± 0.078 in PESs) were linearly correlated with γ (r > 0.999) and almost equal to γ (0.952 for Gebrselassie, 0.918 for Nurmi, and 0.779 ± 0.076 for PESs). The same results were observed when SCrit was computed for tlim equal to 6-28 minutes (SCrit 6-28) and MAS was the maximal velocity sustainable during 14 minutes (S14min). The fact that γ is linearly correlated and almost equal to (Equation is included in full-text article.)or (Equation is included in full-text article.)suggests that exponent γ can be considered as an index of aerobic endurance.

HE COMPLEX PROGRAM OF HEALTH IMPROVEMENT IN STUDENTS WITH DEADAPTATION DISORDERS

The complex program of health promotion for university students with disorders of adaptation processes was developed. The program includes application of dynamic, isometric and breathing exercises at working table during micro-pauses for amelioration of cerebral blood circulation. Increasing of resistance of organism to shortage of oxygen and normalization of vegetative functions. The application of massage of biologically active points applied during scheduled breaks is addressed to optimizing functional conditions of students. The implementation of complex of common developing exercises, application of health promoting running and rainy shower in the end of training exercise is oriented on increasing physical readiness and stimulating students' own adaptive possibilities.The approbation of originally developed program demonstrated its good efficiency in adjustment of deadaptation disorders occurring in the process of education. The results of study demonstrated that in boys and girls after three-months health promoting training neuro-psychic tension decreased, resistance to stress impact increased and anxiety lessened. Simultaneously, increasing of number of students with high level of adaptation to actual social conditions was observed. The amelioration of vegetative resistance of organisms of students was noted. The testing of physical readiness demonstrated that in students, after correcting exercises, muscular strength of wrists increased, velocity force capacities and indices of force endurance in control exercise "jump-rope" ameliorated and suppleness and static resistance of organism. The application of proposed means of health promotion promoted mobilization of workability of nervous cells and nervous system that is substantiated by the results of tapping-test.The application of health promotion program resulted in increasing of academic progress in studies of boys and girls up to 0.4-0.7 points. The obtained data was used to recommend for implementing in educational institutions the developed program of health promoting student youth and minimizing deadaptation disorders occurring in student social environment.

Clinical Assessment Of Muscle Endurance

Evaluation of muscle endurance is important for many clinical populations. PURPOSE: Evaluate the utility of a clinical assessment of muscle endurance that uses twitch electrical stimulation and accelerometer-based mechanomyography (aMMG). METHODS: Twenty healthy participants (9 males; 11 females) and three participants with multiple sclerosis (MS) were tested. Muscle twitch acceleration was measured using an accelerometer placed over the surface of the muscle. The relationship between acceleration and torque was measured during twitch stimulation of the vastus lateralis muscle. Muscle endurance of the forearm and gastrocnemius was measured during 9 minutes of twitch electrical stimulation, in three stages (3min/stage) of increasing frequency (2Hz, 4Hz, and 6Hz). Endurance Index (EI) was calculated as the percent of acceleration at the end of each stimulation stage relative to the peak acceleration. Oxygen saturation was measured using near-infrared spectroscopy. RESULTS: Acceleration correlated with torque during twitch electrical stimulation of the vastus lateralis(mean R2= 0.96±0.04; p<0.05). Measures of EI reproducibility were CV= 2.49±3.67% for the 2Hz stage, CV= 7.36±8.11% for the 4Hz stage, and CV= 4.30±3.09% for the 6Hz stage. EI was significantly higher in the gastrocnemius at the 4Hz (EI =96.1±2.9%) and 6Hz (EI =95.5±2.03%) stages compared to the forearm (4Hz: EI =87.1±9.3%; 6Hz: EI =68.3±17.6%) in healthy controls (p<0.01). Muscle oxygen saturation was not reduced during stimulation of the forearm (72.6±9.8% at 2Hz, 73.2±11.6% at 4Hz, and 71.0±12.5% at 6Hz) compared to baseline (74.3±15.1%; p>0.1). Participants with MS had significantly lower gastrocnemius muscle endurance at the 2Hz (EI =83.6±10.2%), 4Hz (EI =57.2±5.1%), and 6Hz (EI =20.6±8.7%) stages compared to healthy controls (p<0.01). CONCLUSION: Muscle endurance as measured by twitch electrical stimulation and aMMG has the potential to evaluate endurance in various muscles and clinical populations.

Muscle Specific Endurance of the Lower Back Erectors using Electrical Twitch Mechanography

Lower back pain is a common symptom that may be associated with skeletal muscle dysfunction. PURPOSE: This study evaluated the endurance of the lower back muscles in healthy participants using accelerometer-based Mechanomyography (aMMG). METHODS: Surface electrodes and a tri-axial aMMG device were placed on the belly of the erector spinae muscles along the T11-L1 vertebrae. Current levels that evoked visible and tolerable twitch contractions were used. The muscles were stimulated for 3 minutes each at 2, 4, and 6 Hz. An endurance index (EI) was calculated as the maintenance of acceleration at the end of each stage of stimulation relative to the peak acceleration. Subjects (N=7) were tested on two separate days to assess reproducibility. Muscle oxygenation (HbO2) was measured with near infrared spectroscopy (NIRS) during stimulation and during a maximal isometric back extension to induce complete ischemia for signal calibration (N=5). EI was measured in the wrist flexor and vastus lateralis muscles for comparison. RESULTS: EI for the erector spinae muscles were 70.3 + 13.4%, 32.6 + 8.4%, and 19.2 + 6.2 % for 2, 4, 6 Hz, respectively. The coefficients of variation were 9.8%, 13.9%, and 20.3% for 2, 4, 6 Hz, respectively. EI values for the erector spinae were significantly lower than EI values for the arm and the leg (all comparisons, p &lt 0.05). HbO2 values for the erector spinae were 86.4 + 10.9 % at rest, and 77.2 + 15.5%, 84.3 + 14.1%, and 84.1 + 18.9% for 2, 4, 6 Hz, respectively. CONCLUSION: EI is a reproducible method of assessing muscle endurance of the lower back erector muscles that is not related to low oxygen levels. The erector spinae muscles have lower muscle endurance relative to limb muscles.:

Physiological Predictors of Fatigability in Healthy Adults

Fatigability is represented by a decline in performance in relation to the frequency, intensity and duration of physical activity. The use of anaerobic threshold (AT) as an index of endurance is well accepted in the literature. In patients with cardiopulmonary disease, ventilatory efficiency is related to exercise capacity, and therefore may have clinical significance as a fatigability measure. However, this has yet to be determined in healthy individuals. PURPOSE: To characterize physiological determinants of the time to fatigue (TTF) during a vigorous bout of treadmill exercise. METHODS: Subjects were 19 healthy participants (13 females, 6 males; age 26.6 ± 9.1 years; BMI 24.2 ± 2.7 kg/m2) enrolled in the National Institutes of Nursing Research, Fatigue in Healthy Individuals Protocol. Subjects completed a ramp treadmill cardiopulmonary exercise test (CPET) to volitional exhaustion during the initial visit. The anaerobic threshold and two measures of ventilatory efficiency (lowest VE/VCO2 ratio and VE/VCO2 slope to AT) were determined from the CPET. A subsequent visit consisted of a constant work rate test at vigorous-intensity performed to exhaustion in which the TTF represented a measure of performance fatigability. Data are presented as mean ± SD. RESULTS: The TTF was 436.12 ± 175.9 seconds at 240.05 ± 66.48 watts. Subjects achieved an AT of 18.1 ± 4.56 ml/min/kg, lowest VE/VCO2 ratio of 24.72 ± 2.18 and VE/VCO2 slope of 22.49 ± 2.16. Pearson product-moment correlation analysis suggests that both measures of ventilatory efficiency were not significantly correlated to the TTF. The anaerobic threshold was found to be the best predictor of the TTF, with a strong effect size (d= 0.865) suggesting that AT is a reliable predictor of TTF explaining 15% of the variance. CONCLUSIONS: Results from this study suggest that AT remains a better predictor of fatigability compared to measures of ventilatory inefficiency. Further research is needed to determine other objective measures of fatigability. Funding: Intramural Funds from the National Institutes of Nursing Research.

IZOKINETINIŲ IR TRADICINIŲ JĖGOS TRENIRUOČIŲ ĮTAKA MOTERŲ BLAUZDOS LENKIAMŲJŲ RAUMENŲ FUNKCINEI BŪKLEI

Tyrimo tikslas - įvertinti moterų blauzdos lenkiamųjų raumenų jėgos ir ištvermės rodiklių pokyčius po skirtingų treniruočių programų. Tyrime dalyvavo 100 atsitiktinės atrankos būdu atrinktų 18 – 22 metų amžiaus moterų. Tiriamosios suskirstytos į kontrolinę (n = 50), pirmą (n = 25) ir antrą (n = 25) grupę. Kontrolinės grupės moterys stebėtos tiriamuoju periodu, neįtraukiant jų į treniruočių programą. Pirma grupė atliko tradicinių jėgos pratimų programą, antra grupė - izokinetinių treniruočių programą blauzdos tiesiamiesiems ir lenkiamiesiems raumenims lavinti. Visos moterys ištirtos tyrimo pradžioje ir pabaigoje. Tyrimo metu nustatyta, kad tiek tradicinių jėgos pratimų, tiek izokinetinių treniruočių programa padidino moterų blauzdos lenkiamųjų raumenų jėgą (p&amp;lt;0,05) palyginus su kontroline grupe. Antroje tiriamųjų grupėje, po izokinetinių treniruočių programos, blauzdos lenkiamųjų raumenų jėga padidėjo 16,64 proc. nedominuojančioje ir 18,50 proc. dominuojančioje kojoje (p&amp;lt;0,05). Pirmos grupės tiriamosioms, atlikusioms tradicinių jėgos pratimų programą, 9 proc. padidėjo dominuojančios kojos raumenų jėga (p&amp;lt;0,05). Izokinetinės treniruotės taip pat padidino blauzdos lenkiamųjų raumenų ištvermę: nedominuojančioje kojoje 39,77 proc., dominuojančioje - 33,52 (p&amp;lt;0,05). Pirmos grupės tiriamųjų, atlikusių tradicinių jėgos pratimų programą, dominuojančios kojos raumenų ištvermė padidėjo 9,50 proc. (p&amp;lt;0,05). Kontrolinės grupės moterų nedominuojančios kojos ištvermės rodiklis stebimuoju periodu sumažėjo. Tyrimo rezultatai atskleidė, kad izokinetinė treniruotė buvo efektyvesnė nei tradicinių jėgos pratimų programa ir reikšmingiau padidino blauzdos lenkiamųjų raumenų jėgos ir ištvermės rodiklius. Po izokinetinių treniruočių blauzdos lenkiamųjų raumenų jėga padidėjo 18,50 proc., ištvermė - 39,77 proc.

Is fatigue associated with cardiorespiratory endurance among patients suffering from multiple sclerosis?

Fatigue is the most common and disabling symptom among patients suffering from multiple sclerosis (MS). From the initial stages of the disease, a physical deconditioning is also observed among these patients. The aim of this study is to assess the cardiorespiratory endurance (i.e. exercise tolerance functions) and self-reported fatigue, as well as their associations, among patients suffering from MS with mild disability (expanded disability status scale ≤ 4). 21 patients with MS (15 women; age: 26–64 years, median 46 years; duration of disease: 0.33–48 years, median 7.25 years; EDSS 0–4, median 2.5; clinical forms: relapsing–remitting 16, 4 primary progressive, secondary progressive) were evaluated. Cardiorespiratory endurance was assessed by a maximal exercise test on a cycle ergometer, from which different indices were extracted: VO2-max, oxygen uptake efficiency slope (OUES) and physical working capacity at 75% of maximal heart rate (PWC75%). Perceived fatigue, anxiety and depression and quality of life were respectively assessed by the following questionnaires: modified fatigue impact scale (MFIS), fatigue severity scale (FSS), hospital anxiety and depression scale (HADS) and short form health survey (SF-36v2). The majority of the patients ( n = 13, 62%) presented a pathological level of perceived fatigue, based on the FSS criterion (FSS > 5). The cardiorespiratory endurance indices are decreased in all the patients, compared with the normative values from the general population. Low-to-moderate negative correlations ( p < 0.05) are observed between perceived fatigue and VO2-max (FSS: r = –0.59; MFIS: r = –0.43). The OUES is weakly correlated with the MFIS ( r = –0.40), while the PWC75% is not significantly correlated to fatigue measurements. Our data shows that our patients are deconditioned and most have pathological level of fatigue. This fatigue is correlated to physical deconditioning. This suggests that improving exercise tolerance functions could help reducing fatigue among patients suffering from MS with mild neurological disability.

Fatigue design of a cellular phone folder using regression model-based multi-objective optimization

In a folding cellular phone, the folding device is repeatedly opened and closed by the user, which eventually results in fatigue damage, particularly to the front of the folder. Hence, it is important to improve the safety and endurance of the folder while also reducing its weight. This article presents an optimal design for the folder front that maximizes its fatigue endurance while minimizing its thickness. Design data for analysis and optimization were obtained experimentally using a test jig. Multi-objective optimization was carried out using a nonlinear regression model. Three regression methods were employed: back-propagation neural networks, logistic regression and support vector machines. The AdaBoost ensemble technique was also used to improve the approximation. Two-objective Pareto-optimal solutions were identified using the non-dominated sorting genetic algorithm (NSGA-II). Finally, a numerically optimized solution was validated against experimental product data, in terms of both fatigue endurance and thickness index.

THE ERYTHROCYTE MEMBRANE ENDURANCE AGAINST TISSUE ISCHEMIA IN PATIENTS WITH HYPERTENSIVE DISEASE AND ISCHEMIC HEART DISEASE AND ITS RELATIONSHIP WITH ENDOGENOUS FACTORS

Aim. To find out the type of erythrocyte membrane endurance to local ischemia in patients with AH and AP including its relationship with endogenous factors. Material and methods. Totally 60 men included with stable form of angina pectoris and 50 men with hypertension of the age 40-55 y.o. To compare the relationships that were found with normal values the parameters studied also were measured in healthy men (n=20) at the age 27±2,5 y.o. The prominence of changes in erythrocyte membrane was evaluated by their comparison before and after local ischemia. In every patient the endurance index (index(m)) was calculated for the erythrocyte membrane. Then we studied endogenous factors that modified the shifts of erythrocyte membrane endurance in the patients studied. Results. During the study it was shown that the erythrocyte membrane endurance to tissue ischemia in AH and AP patients was significantly lower comparing to healthy males. Also in patients there was relation between shifts of membrane endurance and baseline level of various endogenous factors activity. In AP patients the endurance of membrane could be modified by five predictors: blood viscosity in moderate diameter vessels, ACE and less von Willebrand factor. In both groups the increase of baseline ACE and blood viscosity was followed by the decrease of membrane endurance. But if the ischemia developed at the background of weak ACE activity or low blood viscosity, then erythrocyte membrane was more endurable to this pathogen factor. Conclusion. The relationships found for endogenous factors and membrane endurance, it seems, shows differences in genesis of angina pectoris and hypertension. The relations require confirmation in other patients selections with the same pathology and only then can be used for the development of further findings of the main pathogenetic chains in the patients with AH and AP, as for additional treatment strategies development.

New Approach for the Optimal Allocation of Wind Power in a Rural Power System

This paper presents a new approach to estimate wind speed and install a wind power turbine (WPT) in a power system. The entire installation procedure includes selecting appropriate buses and verifying the power system after installing the WPT. Two reliability indices, the power index in crisis time (PICT) and the endurance index of crisis hours (EICH), were developed and used for determining the reliability level of target buses for WPT installation. The stability and reliability of the hybrid power system formed was verified by determining the reference frequency and voltage. The results described in this paper can be applied to other small power systems using distributed generation, such as hydroelectric power generation.

Five-Kilometers Time Trial: Preliminary Validation of a Short Test for Cycling Performance Evaluation.

Background:The five-kilometer time trial (TT5km) has been used to assess aerobic endurance performance without further investigation of its validity.Objectives:This study aimed to perform a preliminary validation of the TT5km to rank well-trained cyclists based on aerobic endurance fitness and assess changes of the aerobic endurance performance.Materials and Methods:After the incremental test, 20 cyclists (age = 31.3 ± 7.9 years; body mass index = 22.7 ± 1.5 kg/m2; maximal aerobic power = 360.5 ± 49.5 W) performed the TT5km twice, collecting performance (time to complete, absolute and relative power output, average speed) and physiological responses (heart rate and electromyography activity). The validation criteria were pacing strategy, absolute and relative reliability, validity, and sensitivity. Sensitivity index was obtained from the ratio between the smallest worthwhile change and typical error.Results:The TT5km showed high absolute (coefficient of variation < 3%) and relative (intraclass coefficient correlation > 0.95) reliability of performance variables, whereas it presented low reliability of physiological responses. The TT5km performance variables were highly correlated with the aerobic endurance indices obtained from incremental test (r > 0.70). These variables showed adequate sensitivity index (> 1).Conclusions:TT5km is a valid test to rank the aerobic endurance fitness of well-trained cyclists and to differentiate changes on aerobic endurance performance. Coaches can detect performance changes through either absolute (± 17.7 W) or relative power output (± 0.3 W.kg-1), the time to complete the test (± 13.4 s) and the average speed (± 1.0 km.h-1). Furthermore, TT5km performance can also be used to rank the athletes according to their aerobic endurance fitness.

The respiration pattern as an indicator of the anaerobic threshold.

The anaerobic threshold (AT) is a good index of personal endurance but needs a laboratory setting to be determined. It is important to develop easy AT field measurements techniques in order to rapidly adapt training programs. In the present study, it is postulated that the variability of the respiratory parameters decreases with exercise intensity (especially at the AT level). The aim of this work was to assess, on healthy trained subjects, the putative relationships between the variability of some respiration parameters and the AT. The heart rate and respiratory variables (volume, rate) were measured during an incremental exercise performed on a treadmill by healthy moderately trained subjects. Results show a decrease in the variance of 1/tidal volume with the intensity of exercise. Consequently, the cumulated variance (sum of the variance measured at each level of the exercise) follows an exponential relationship with respect to the intensity to reach eventually a plateau. The amplitude of this plateau is closely related to the AT (r=-0.8). It is concluded that the AT is related to the variability of the respiration.

Forecasting of housing stock returns and housing prices

Purpose– The purpose of this paper is to create an endurance index of housing investor sentiment and use it to forecast housing stock returns. This study performs not only in-sample and out-of-sample forecasting, like many previous studies did, but also a true forecasting by using all lag terms of independent variables. In addition, an evaluation procedure is applied to quantify the quality of forecasts.Design/methodology/approach– Using a binomial probability distribution model, this paper creates an endurance index of housing investor sentiment. The index reflects the probability of the high or low stock price being the close price for the Philadelphia Stock Exchange Housing Sector Index. This housing investor sentiment endurance index directly uses housing stock price differentials to measure housing investor reactions to all relevant news. Empirical results in this study suggest that the index can not only play a significant role in explaining variations in housing stock returns but also have decent forecasting ability.Findings– Results of this study reveal the considerable forecasting ability of the index. Monthly forecasts of housing stock returns have an overall accuracy of 51 per cent, while the overall accuracy of 8-quarter rolling forecasts even reaches 84 per cent. In addition, the index has decent forecasting ability on changes in housing prices as suggested by the strong evidence of one-direction causal relations running from the endurance index to housing prices. However, extreme volatility of housing stock returns may impair the forecasting quality.Practical implications– The endurance index of housing investor sentiment is easy to construct and use for forecasting housing stock returns. The demonstrated predictability of the index on housing stock returns in this study can have broad implications on housing-related business practices through providing an effective forecasting tool to investors and analysts of housing stocks, as well as housing policy-makers.Originality/value– Despite different investor sentiment proxies suggested in the previous studies, few of them can effectively predict stock returns, due to some embedded limitations. Many increases and decreases inn prices cancel out each other during the trading day, as many unreliable sentiments cancel out each other. This dynamic process reveals not only investor sentiment but also resilience or endurance of sentiment. It is only long-lasting resilient sentiment that can be built in the closing price. It means that the only feasible way to use investor sentiment contained in stock prices to forecast future stock prices is to detach resilient investor sentiment from stock prices and construct an index of endurance of investor sentiment.

A comparison of the physical fitness, athletic performance and competitive achievements of junior and senior tennis players

&lt;p&gt;The Japan Tennis Association established the Tennis Field Test as a tool for aiding the development of effective coaching methods and improving the competitive achievements of individual elite tennis players. On the basis of such evaluations, specific coaching methods can be developed for individual tennis players. This study aims to evaluate the physical fitness and athletic performance of tennis players using the Tennis Field Test, and to compare these attributes between players of different ages and abilities. A total of 48 tennis players participated, of which 24 were junior players (including 15 regional representatives), and 24 were senior players (including 18 national representatives). The subjects were further subdivided into average and superior groups on the basis of their competitive achievements in regional or national tournaments. All subjects participated in the Tennis Field Test, which consists of the following six items: the number of sit-ups performed in 30 sec (an index of muscular endurance), the standing long jump distance (an index of leg power), the sit and reach test (an index of flexibility), the time taken to perform the spider run (an index of agility), the time taken to sprint 10 m (an index of speed), and the distance run in three minutes (an index of whole-body endurance capacity). In this study, the subjects’ sit and reach test data were not examined due to differences in the measurement methods used between junior and senior tennis players. Among the junior tennis players, the superior group performed faster in the spider run than the average group (p = 0.0011). Among the senior tennis players, the superior group achieved a longer mean distance during the three-minute run than the average group (p = 0.0223). The test results of the remaining items for both groups were relatively similar. This study suggests that competitive achievement is associated with agility among junior tennis players, and is associated with whole-body endurance capacity among senior tennis players.&lt;/p&gt;

Agronomic Efficiency of Biosolid as Source of Nitrogen to Banana Plants

Sewage sludge (SS) or biosolid has been studied as source of nutrient for several different plant species. It also contributes to soil fertility recycling organic matter and plant nutrients. This followup work examines a three-year (2001–2004) field experiment designed to evaluate the response of banana plants (Cavendish subgroup) to the application of biosolid as source of nitrogen. The treatments consisted of control (mineral PK, no N), three rates of sludge, and two rates of mineral NPK fertilizer. Plant and soil N concentration, fruit yield, plant height, stem diameter, and foliar endurance index were measured. Fruit yield with mineral fertilization or sludge applications did not differ statistically(P&gt;0.05). Application of biosolid resulted in statistically significant higher agronomic efficiency(P&lt;0.05)in comparison to mineral fertilizers. The concentration of soil mineral nitrogen increased using mineral fertilizer or sludge until 0.80 m after three years of application. The effect of the source of N was smaller than the effect of the rate. Biosolid can be used as source of N for banana growers.

Forecasting ability of the investor sentiment endurance index: The case of oil service stock returns and crude oil prices

Using a binomial probability distribution model this paper creates an endurance index of oil service investor sentiment. The index reflects the probability of the high or low stock price being the close price for the PHLX Oil Service Sector Index. Results of this study reveal the substantial forecasting ability of the sentiment endurance index. Monthly and quarterly rolling forecasts of returns of oil service stocks have an overall accuracy as high as 52% to 57%. In addition, the index shows decent forecasting ability on changes in crude oil prices, especially, WTI prices. The accuracy of 6-quarter rolling forecasts is 55%. The sentiment endurance index, along with the procedure of true forecasting and accuracy ratio, applied in this study provides investors and analysts of oil service sector stocks and crude oil prices as well as energy policy-makers with effective analytical tools.

Relationship between Physical Fitness and Cognitive Function in Male College Students

A growing number of studies have suggested a positive association between physical fitness and cognitive function among adults. However, the magnitude of the association is affected by several potential factors, and the specifics of the relationship are not yet fully understood. Therefore, this study attempted to examine the correlations between various physical fitness types and cognitive performance, by considering as two potential factors. One hundred sixty-three male college students were recruited for this study. Physical fitness of participants, including cardiovascular fitness, muscular power, flexibility, muscle endurance and body mass index were measured. Cognitive performance was measured via the Stroop test that assessed basic information processing and inhibition aspect of executive function. The results indicated that cardiovascular fitness was positively associated with the task conditions reflected in executive functions. Muscle power was positively associated with all conditions related to Stroop test. Moreover, muscle endurance and flexibility was positively correlated to executive function and non-executive functions, respectively, whereas none of these relationships was observed with body mass index and the Stroop test performance. The present study suggested that specific physical fitness indices might exhibit selective beneficial effects on cognitive function, which was in line with previously proposed selective improvement hypothesis. Our study further extended the hypothesis to other type of physical fitness. Finally, several potential underlying mechanisms, with respective of neuroelectrical, brain function, and psychological aspects were provided for future research.

Maximal strength, muscular endurance and inflammatory biomarkers in young adult men.

The aim was to study associations of maximal strength and muscular endurance with inflammatory biomarkers independent of cardiorespiratory fitness in those with and without abdominal obesity. 686 young healthy men participated (25±5 years). Maximal strength was measured via isometric testing using dynamo-meters to determine maximal strength index. Muscular endurance index consisted of push-ups, sit-ups and repeated squats. An indirect cycle ergometer test until exhaustion was used to estimate maximal aerobic capacity (VO2max). Participants were stratified according to those with (>102 cm) and those without abdominal obesity (<102 cm) based on waist circumference. Inflammatory factors (C-reactive protein, interleukin-6 and tumour necrosis factor alpha) were analysed from serum samples. Maximal strength and muscular endurance were inversely associated with IL-6 in those with (β=-0.49, -0.39, respectively) (p<0.05) and in those without abdominal obesity (β=-0.08, -0.14, respectively) (p<0.05) adjusted for smoking and cardio-respiratory fitness. After adjusting for smoking and cardiorespiratory fitness, maximal strength and muscular endurance were inversely associated with CRP only in those without abdominal obesity (β=-0.11, -0.26, respectively) (p<0.05). This cross-sectional study demonstrated that muscular fitness is inversely associated with C-reactive protein and IL-6 concentrations in young adult men independent of cardiorespi-ratory fitness.

The applicability of proprioceptive and endurance measurement protocols to treat patients with chronic non-specific neck pain

Background: Neck pain constitutes a common disorder in modern societies. Numerous complications and episodes of recurrence have been observed with neck pain while few statistically evidence-based exercise protocols have been designed. The objective of this study was to detect and compare the applicability of two proprioceptive and endurance measurement protocols to treat patients with chronic non-specific neck pain. Methods: This was a single blinded, randomized clinical trial conducted at Mostapha Khomeini Hospital, Behbahan, Iran. Forty seven patients (16 males and 31 females) with chronic non-specific neck pain participated in this study. Subjects were randomized into two groups: endurance training and proprioceptive training. Each training was performed for ten subsequent days. A pressure biofeedback was used to measure the endurance of neck muscles and a laser resource device to measure the cervicocranial joint position error prior to therapy, on fifth, tenth sessions after the 1 st day of treatment and 45 days after the last treatment day. Results: Significant differences were found between before and after therapy in terms of endurance index, joint position error, and pain measurments (p<0.05, p<0.01 and p<0.05) in both groups. After therapy, endurance index was significantly more pronounced in the endurance group, whereas the improvement in joint position error index was more pronounced in the proprioceptive group. Conclusion: The use of endurance and proprioceptive based measurement programs as was used in this study can be recommended to improve endurance, reduce proprioceptive error and pain in patients with chronic non-specific neck pain. Endurance exercise was a more efficient method for improving endurance and proprioceptive training was better in resolving joint position error and pain. Both protocols appeared to be applicable to treat patients with chronic non-specific neck pain.