Prolonged Running Research Articles

Early changes of the anemia phenomenon in male 100-km ultramarathoners

BackgroundSports anemia is a widely observed phenomenon after prolonged running. There are various factors that contribute to sports anemia, including hemodilution, exercise-induced oxidative stress, iron deficiency, gastrointestinal bleeding, hematuria, and hemolysis resulting from foot-strike and/or from compression of contracting muscles on capillaries. Until now, there has been no published report that describes the overall hematological, urinary, and fecal consequences in Asian male ultramarathoners after a 100-km (62.5-mile) ultramarathon event. MethodsA total of 25 male runners were recruited into our study. Blood was drawn 1 week before, immediately after, and then 24 hours subsequent to the race. Hematological samples were analyzed for the anemia phenomenon. Additionally, urinary and fecal samples were collected before and after the race for detection of occult blood. ResultsThe blood hemoglobin and erythropoietin values of the recruited runners showed a statistically significant rise in the immediate post-race values and a rapid drop in values at 24 hours post-race. Blood concentrations of red blood cells and hematocrit were significantly lower at 24 hours post-race compared with pre-race. The white blood cell count, interleukin-6, tumor necrosis factor-alpha, high-sensitivity C-reactive protein, and ferritin all showed significant increases both immediately after and 24 hours post-race compared with pre-race hematological values. There were immediate decreases of both haptoglobin and iron, as well as an increase of total iron-binding capacity levels in post-race blood tests. For both urinary and fecal samples, there was a statistically significant difference between the pre- and post-race results in occult blood. ConclusionRunning a 100-km ultramarathon will induce substantial sports anemia, and oxidative stress response, hemolysis, hematuria, and gastrointestinal bleeding are typical factors that contribute to its onset.

Medial Longitudinal Arch Mechanics Before and After a 45 Minute Run.

Abstract BACKGROUND:Medial longitudinal arch integrity following prolonged running has yet to be well documented. Our purpose was to quantify changes in medial longitudinal arch kinematics before and after a 45 minute run in healthy recreational runners. METHODS:Thirty runners performed barefoot seated, standing, and running trials before and after a 45 minute shod treadmill run. Navicular displacement, arch lengthening, and arch height index were used to quantify arch deformation, and arch rigidity index was used to quantify arch stiffness. RESULTS:There was no statistical difference in navicular displacement (mean (95% CI): 5.6 (4.7-6.4)), arch lengthening (3.2 (2.6-3.9)), change in arch height index (0.015 (0.012-0.018)), or arch rigidity index (0.95 (0.94-0.96)) after the 45 minute run (all MANOVA P{greater than or equal to}0.065). CONCLUSIONS:Since there was no statistically significant change in arch deformation or rigidity, either the structures of a healthy, intact medial longitudinal arch are capable of adapting to cyclical loading or they are capable of withstanding a 45 minute run without compromise.

Medial longitudinal arch mechanics before and after a 45-minute run.

Medial longitudinal arch integrity after prolonged running has yet to be well documented. We sought to quantify changes in medial longitudinal arch kinematics before and after a 45-min run in healthy recreational runners. Thirty runners performed barefoot seated, standing, and running trials before and after a 45-min shod treadmill run. Navicular displacement, arch lengthening, and the arch height index were used to quantify arch deformation, and the arch rigidity index was used to quantify arch stiffness. There were no statistically significant differences in mean (95% confidence interval) values for navicular displacement (5.6 mm [4.7-6.4 mm]), arch lengthening (3.2 mm [2.6-3.9 mm]), change in arch height index (0.015 [0.012-0.018]), or arch rigidity index (0.95 [0.94-0.96]) after the 45-min run (all multivariate analyses of variance P ≥ .065). Because there were no statistically significant changes in arch deformation or rigidity, the structures of a healthy, intact medial longitudinal arch are capable of either adapting to cyclical loading or withstanding a 45-min run without compromise.

European Journal Of Sport Science: The Influence of Wearing Compression Stockings on Performance Indicators and Physiological Responses Following a Prolonged Trail Running Exercise

The authors have analyzed 400 publications in international refereed journals, «European Journal of Sport Sciences» for the period from 2001 to 2012. The classification of scientific publications has been done, the tendencies in the development of major trends of sports science in Western countries have been identified.

Temporal Response of Arterial Stiffness to Ultra-Marathon

The purpose of this investigation was to characterize the arterial stiffness of male ultra-marathon runners (n = 9) using pulse wave velocity (cfPWV) and radial tonometry over the course of an ultra-marathon and during recovery. Measures were collected at rest, immediately following 45 km/75 km of running, then following 60 and 90 min of recovery. No statistical difference was found between baseline cfPWV and normative values. The cfPWV of ultra-endurance runners decreased at 45 km (3.4 ± 1.6 m/s, p=0.006), followed by an increase (1.6 ± 1.8 m/s, p = 0.04) toward baseline levels at the 75 km mark. Radial tonometry measures also indicated small artery stiffness was transiently increased after 75 km. The amount of training time (r = 0.82, p = 0.007) and the duration of a typical training session (r = 0.73, p = 0.03) were correlated strongly with persisting decrements in large artery compliance at 60 min of recovery. The finding that arterial stiffness decreased at the 45 km distance and then reverted back toward baseline levels with prolonged running, may indicate a role of exercise duration or accumulated stress for affecting vascular compliance. At present, it is premature to suggest that athletes should alter training or racing practices to protect vascular health.

Relationship Between Tests of Physical Qualities, Team Selection, and Physical Match Performance in Semiprofessional Rugby League Players

This study investigated the physical qualities that discriminated state-based rugby league players competing for selection in a semiprofessional rugby league team, and determined the relationship between tests of physical qualities and physical match performance in these players. Thirty-two rugby league players (mean ± SD age, 24 ± 3 years) from a Queensland Cup rugby league squad participated in this study. The players performed tests of upper-body strength (3 repetition maximum [RM] bench press; 3RM weighted chin-up), upper-body strength endurance (body-mass maximum repetition bench press), lower-body strength (3RM squat), lower-body power (vertical jump), and prolonged high-intensity intermittent running ability (Yo-Yo intermittent recovery test, level 1). Global positioning system data, sampling at 10 Hz, were collected during 5 Queensland Cup rugby league matches. Selected players had greater (p < 0.05) 3RM squat, 3RM chin-up, body-mass bench press, vertical jump, and Yo-Yo intermittent recovery test performances than nonselected players. After controlling for playing position, players with better 3RM squat performances covered greater total distances (r = 0.98, p < 0.05) including greater distances at low (r = 0.98, p < 0.05) and high (r = 0.97, p < 0.05) speeds. Significant associations (r = 0.96, p < 0.05) were also found between 3RM squat performances and the number of repeated high-intensity effort bouts performed in competition. These findings highlight the importance of lower-body strength, upper-body strength and endurance, and prolonged high-intensity intermittent running ability to team selection in semiprofessional rugby league. Furthermore, our findings suggest that well-developed lower-body strength contributes to effective physical match performance in semiprofessional rugby league players.

Running Economy During a Simulated 60-km Trial

The effect of a prolonged running trial on the energy cost of running (C(r)) during a 60-km ultramarathon simulation at the pace of a 100-km competition was investigated in 13 men (40.8 ± 5.6 y, 70.7 ± 5.5 kg, 177.5 ± 4.5 cm) and 5 women (40.4 ± 2.3 y, 53.7 ± 4.4 kg, 162.4 ± 4.8 cm) who participated in a 60-km trial consisting of 3 consecutive 20-km laps. Oxygen uptake (VO(2)) at steady state was determined at constant speed before the test and at the end of each lap; stride length (SL) and frequency and contact time were measured at the same time points; serum creatine kinase (S-CPK) was measured before and at the end of the test. C(r) in J · kg(-1) · m(-1), as calculated from VO(2ss) and respiratory-exchange ratio, did not increase with distance. SL significantly decreased with distance. The net increase in S-CPK was linearly related with the percentage increase of C(r) observed during the trial. It is concluded that, in spite of increased S-CPK, this effort was not able to elicit any peripheral or central fatigue or biomechanical adaptation leading to any modification of C(r).

Acute changes to biomarkers as a consequence of prolonged strenuous running

A single bout of strenuous running exercise results in perturbations to numerous biomarkers. An understanding of these is important when analysing samples from individuals who have recently performed such exercise. A literature search was undertaken using the search terms, exercise, marathon and delayed onset of muscle soreness. The search was then refined using the terms for key biomarkers known to be altered by exercise. The magnitude of changes to biomarkers is proportional to the severity of the running bout. Familiar, moderate intensity running exercise produces brief transient changes in common biomarkers such as lactate, whereas more severe bouts of running exercise, such as marathons and ultra-marathon events can produce changes to biomarkers that are normally associated with pathology of the muscles, liver and heart. Examples being changes to concentrations and/or activity of myoglobin, leucocytes, creatine kinase, bilirubin, cardiac troponins, lactate dehydrogenase, alanine aminotransferase and aspartate aminotransferase. While persisting for longer, these changes are also transient and full recovery occurs within days, without any apparent long-term adverse consequences. Additionally, unfamiliar exercise involving forceful eccentric muscle contractions, such as running downhill, can cause increases in creatine kinase and delayed onset of muscle soreness that peaks 36-72 h after the exercise bout. Strenuous running exercise can produce changes to biomarkers that are normally associated with disease and injury, but these do not necessarily reflect chronic pathology.

Immediate Effect of Exercise on Achilles Tendon Properties

Understanding the mechanical and morphological adaptation of the Achilles tendon (AT) in response to acute exercise could have important implications for athletic performance, injury prevention, and rehabilitation. The purpose of this study was to conduct a systematic review and critical evaluation of the literature to determine the immediate effect of a single bout of exercise on the mechanical and morphological properties of the AT in vivo. Five electronic research databases were systematically searched for intervention-based studies reporting mechanical and morphological properties of the AT after a single bout of exercise. Searches revealed 3292 possible articles; 21 met the inclusion criteria. There is evidence that maximal isometric contractions and prolonged static stretching (>5 min) of the triceps surae complex cause an immediate decrease in AT stiffness, whereas prolonged running and hopping have minimal effect. Limited but consistent evidence exists, indicating that AT hysteresis is reduced after prolonged static stretching. Consistent evidence supports a reduction in free AT diameter (anterior-posterior) after dynamic ankle exercise, and this change appears most pronounced in the healthy tendon and after eccentric exercise. The mechanical and morphological properties of the AT in vivo are affected by acute exercise in a mode- and dose-dependent manner. Transient changes in AT stiffness, hysteresis, and diameter after unaccustomed exercise modes and doses may expose the tendon to increased risk of strain injury and impact on the mechanical function of the triceps surae muscle-tendon unit.

Influence of individual energy cost on running capacity in warm, humid environments

Challenging environmental conditions including heat and humidity are associated with particular risks to the health of runners and triathletes during prolonged events. The heat production of a runner is the product of its energy cost of running (C r) by its velocity. Since C r varies greatly among humans, those individuals with high C r are more exposed to heat stress in warm and humid conditions. Although risk factor awareness is crucial to the prevention of heat stroke and potential fatalities associated therewith, how C r affects the highest sustainable velocity (V) at which maximal heat loss matches heat production has not been quantified to date. Here, we computed in virtual runners weighting 45-75kg, the influence of C r variability from 3.8 to 4.4J·m(-1)·kg(-1) on V. Heat loss by radiation, convection, and conduction was assessed from known equations including body dimensions, running velocity (3.4-6.2m·s(-1)), air temperature (T a, 10-35°C) and relative humidity (r h, 50, 70 and 90%). We demonstrated a marked and almost linear influence of C r on V in hot and humid conditions: +0.1J·kg(-1)·m(-1) in C r corresponded to -4% in V. For instance, in conditions25°C r h 70%, 65-kg runners with low C r could sustain a running speed of 5.7m·s(-1) as compared to only 4.3m·s(-1) in runners with high C r, which is huge. We conclude that prior knowledge of individual C r in athletes exposed to somewhat warm and humid environments during prolonged running is one obvious recommendation for minimizing heat illness risk.

Relationship Between Tests of Physical Qualities and Physical Match Performance in Elite Rugby League Players

Previous investigators have reported significant relationships between tests of physical qualities and physical match performance in high-intensity, intermittent team sport (e.g., soccer) players. Although rugby league requires competitors to perform high-intensity running, unlike most other high-intensity intermittent team sports, the physical demands are significantly increased through the large amounts of tackling, wrestling, and grappling that players are required to perform during match play. This study investigated the relationship between tests of physical qualities and match performance in professional rugby league players and determined whether running capacities were associated with the collision and repeated high-intensity effort demands of match play. Thirty-eight elite rugby league players (mean ± SD, age, 23.1 ± 2.7 years) performed tests of repeated sprint ability (12 × 20-m sprints on a 20-second cycle), prolonged high-intensity intermittent running ability (8 × 12-second shuttle sprints on a 48-second cycle), and estimated maximal aerobic power (VO2max) (multistage fitness test). Global positioning system data were collected during 16 professional rugby league matches. Players with better, prolonged, high-intensity intermittent running ability covered greater total distance and greater distance in high-speed running during match play. However, inconsistent relationships were found between tests of running abilities and other match performance variables, with prolonged high-intensity running ability (negative), VO2max (positive), and repeated-sprint ability (no relationship) differentially associated with the total number of collisions and repeated high-intensity effort bouts performed in competition. These findings demonstrate the importance of prolonged high-intensity running ability to the match running performance of elite rugby league players but also highlight the need for game-specific conditioning to prepare players for the high-intensity collision and repeated-effort demands of the game.

Comparação das variáveis eletromiográficas e cinemáticas entre uma corrida do "triathlon" e uma corrida prolongada

A corrida e o ciclismo realizados com uma mesma duração e intensidade podem apresentar diferentes respostas biomecânicas e metabólicas durante um protocolo de fadiga devido à sobrecarga mecânica e à especificidade técnica de cada modalidade. O objetivo do presente estudo foi avaliar os efeitos da fadiga proveniente de uma corrida de 10 km, precedida por ciclismo ou corrida, no padrão de passada e no sinal eletromiográfico (EMG). Nove triatletas do sexo masculino com tempo de prática superior a dois anos participaram do estudo. Os testes foram realizados em duas etapas: corrida do "triathlon" (40 km de ciclismo seguidos de 10 km de corrida) e corrida prolongada (corrida com duração igual ao tempo que o atleta levou para percorrer os 40 km de ciclismo, seguidos de mais 10 km de corrida). Uma análise cinemática (frequência e amplitude de passada) e eletromiográfica correspondentes às 10 passadas registradas no 5º km de cada corrida foi realizada. As curvas de EMG foram retificadas e filtradas para cálculo das curvas de RMS. A partir da média das curvas de EMG foram obtidos os valores de pico de RMS para os músculos reto femoral, vasto lateral e bíceps femoral. Maiores valores de frequência de passada e do sinal EMG do músculo bíceps femoral foram obtidos na corrida prolongada quando comparada com a corrida do "triathlon". Esses resultados parecem estar relacionados a maior fadiga proveniente da corrida prolongada devido às maiores exigências mecânicas.

Knee abduction angular impulses during prolonged running with wedged insoles

Wedged insoles may produce immediate effects on knee abduction angular impulses during running; however, it is currently not known whether these knee abduction angular impulse magnitudes are maintained throughout a run when fatigue sets in. If changes occur, this could affect the clinical utility of wedged insoles in treating conditions such as patellofemoral pain. Thus, the purpose of this study was to determine whether knee abduction angular impulses are altered during a prolonged run with wedged insoles. It was hypothesized that knee abduction angular impulses would be reduced following a prolonged run with wedged insoles. Nine healthy runners participated. Runners were randomly assigned to either a 6-mm medial wedge condition or a 6-mm lateral wedge condition and then ran continuously overground for 30 min. Knee abduction angular impulses were quantified at 0 and 30 min using a gait analysis procedure. After 2 days, participants returned to perform the same test but with the other wedge type. Two-way repeated-measures analysis of variance was used to evaluate main effects of wedge condition and time and interactions between wedge condition and time (α = 0.05). Paired t-tests were used for post hoc analysis (α = 0.01). No interaction effects (p = 0.958) were found, and knee abduction angular impulses were not significantly different over time (p = 0.384). Lateral wedge conditions produced lesser knee abduction angular impulses than medial conditions at 0 min (difference of 2.79 N m s, p = 0.006) and at 30 min (difference of 2.76 N m s, p < 0.001). It is concluded that significant knee abduction angular impulse changes within wedge conditions do not occur during a 30-min run. Additionally, knee abduction angular impulse differences between wedge conditions are maintained during a 30-min run.

Salivary antimicrobial protein response to prolonged running.

IntroductionProlonged exercise may compromise immunity through a reduction of salivary antimicrobial proteins (AMPs). Salivary IgA (IgA) has been extensively studied, but little is known about the effect of acute, prolonged exercise on AMPs including lysozyme (Lys) and lactoferrin (Lac).ObjectiveTo determine the effect of a 50-km trail race on salivary cortisol (Cort), IgA, Lys, and Lac.Methods14 subjects: (6 females, 8 males) completed a 50km ultramarathon. Saliva was collected pre, immediately after (post) and 1.5 hrs post race (+1.5).ResultsLac concentration was higher at +1.5 hrs post race compared to post exercise (p < 0.05). Lys was unaffected by the race (p > 0.05). IgA concentration, secretion rate, and IgA/Osm were lower +1.5 hrs post compared to pre race (p < 0.05). Cort concentration was higher at post compared to +1.5 (p < 0.05), but was unaltered from pre race levels. Subjects finished in 7.81±1.2 hrs. Saliva flow rate did not differ between time points. Saliva Osm increased at post (p < 0.05) compared to pre race.ConclusionsThe intensity could have been too low to alter Lys and Lac secretion rates and thus, may not be as sensitive as IgA to changes in response to prolonged running. Results expand our understanding of the mucosal immune system and may have implications for predicting illness after prolonged running.

The effects of prolonged running on foot posture: a repeated measures study of half marathon runners using the foot posture index and navicular height

BackgroundDifferent foot postures are associated with alterations in foot function, kinetics and the subsequent occurrence of injury. Little is known about changes in foot posture following prolonged weightbearing exercise. This study aimed to identify changes in foot posture after running a half marathon.MethodsFoot posture was measured using the Foot Posture Index (FPI-6) and navicular height in thirty volunteer participants before and after running a half marathon. FPI-6 scores were converted to Rasch logit values and means compared for these and navicular height using an ANOVA.ResultsThere was a 5 mm drop in navicular height in both feet when measured after the half marathon (P < 0.05). The FPI-6 showed a side x time interaction with an increase in score indicating a more ‘pronated’ position in the left foot of + 2 [Rasch value + 1.7] but no change in the right foot (+ 0.4 [+ 0.76]) following the half marathon.ConclusionThe apparent differences between the FPI-6 and navicular height on the right foot may be because the FPI-6 takes soft tissue contour changes into consideration whilst the navicular height focuses on skeletal changes. The changes in foot posture towards a more pronated position may have implications for foot function, and therefore risk of injury; shoe fit and comfort and also the effect of therapeutic orthoses worn during prolonged running.

Leukocyte chemotactic cytokine and leukocyte subset responses during ultra-marathon running

PurposeThe aim of this study was to assess leukocyte chemotactic cytokine and leukocyte subset responses during ultra-marathon running. Leukocyte chemokines such as interleukin (IL)-8, interferon gamma-induced protein-10 (IP-10), regulated upon activation, normal T-cell expressed and secreted (RANTES), and eotaxin are involved in leukocyte recruitment. MethodsAmong 60 male amateur endurance runner volunteers, 18 finished the course (a 308km continuous race from Kanghwado to Kangneung, South Korea). Their average age, height, and body mass were 52.8±5.0years, 167.6±5.2cm, and 64.5±1.2kg, respectively. Blood samples were collected at 0, 100, 200, and 308km during the race for analysis of white blood cells and serum concentrations of IL-8, IP-10, RANTES, eotaxin, IL-6, creatine kinase (CK), and C-reactive protein (CRP). ResultsMuscle and liver damage indicators (IL-6, CK, and CRP) were maximally elevated as a result of marathon running. Total leukocytes, neutrophils, and monocytes increased significantly during the event (leukocytosis, neutrophilia, and monocytosis, respectively). However, lymphocytes and eosinophils decreased significantly during the event (lymphopenia and eosinopenia, respectively). Serum levels of the neutrophil chemokine IL-8 increased maximally at 100km and were maintained. Monocyte-lymphocyte chemokine IP-10 concentration decreased during the latter part of the race. The eosinophil chemokine eotaxin decreased gradually during the race, and no difference was observed in eosinophil chemokine RANTES levels. ConclusionThese observations indicate that prolonged endurance ultra-marathon running was associated with significant systemic inflammation and perturbation in leukocyte subsets. Leukocyte chemotactic cytokines such as IL-8, IP-10, eotaxin showed similar patterns of responses in related leukocyte subsets, but RANTES did not.

Residents Teaching Residents: How the Duty Hour Limits Have Changed Us

Residents Teaching Residents: How the Duty Hour Limits Have Changed Us

The influence of wearing compression stockings on performance indicators and physiological responses following a prolonged trail running exercise

The objective of this study was to investigate the effects of wearing compression socks (CS) on performance indicators and physiological responses during prolonged trail running. Eleven trained runners completed a 15.6 km trail run at a competition intensity whilst wearing or not wearing CS. Counter movement jump, maximal voluntary contraction and the oxygenation profile of vastus lateralis muscle using near-infrared spectroscopy (NIRS) method were measured before and following exercise. Run time, heart rate (HR), blood lactate concentration and ratings of perceived exertion were evaluated during the CS and non-CS sessions. No significant difference in any dependent variables was observed during the run sessions. Run times were 5681.1±503.5 and 5696.7±530.7 s for the non-CS and CS conditions, respectively. The relative intensity during CS and non-CS runs corresponded to a range of 90.5–91.5% HRmax. Although NIRS measurements such as muscle oxygen uptake and muscle blood flow significantly increased following exercise (+57.7% and + 42.6%,+59.2% and + 32.4%, respectively for the CS and non-CS sessions, P<0.05), there was no difference between the run conditions. The findings suggest that competitive runners do not gain any practical or physiological benefits from wearing CS during prolonged off-road running.

Increase in IL-6, TNF-α, and MMP-9, but not sICAM-1, concentrations depends on exercise duration

It has been suggested that exercise intensity is of importance in the regulation of increase in pro-inflammatory molecules, but there is still a debate about the effect of duration on these molecules. Therefore, the effect of exercise duration on the serum concentrations of interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), soluble form of intercellular adhesion molecule-1 (sICAM-1), and matrix metalloproteinase-9 (MMP-9) was studied in 22 half-marathon (HM) and 18 marathon (M) male amateur runners who completed their exercise task in 1.8 ± 0.2 (mean ± standard deviation) and 3.6 ± 0.4 h, respectively (thus, average speed was 11.7 ± 1.5 and 11.9 ± 1.8 km h(-1), respectively). Blood was sampled 2 days before, 15 min after, and 28 h after the race. IL-6, TNF-α, and MMP-9 always increased immediately after exercise, but the increase was larger (P < 0.05) in M versus HM (∆IL-6: 31 ± 24 vs. 5 ± 4 pg ml(-1); ∆TNF-α: 1.7 ± 1.9 vs. 0.5 ± 0.8 pg ml(-1); MMP-9: 288 ± 216 vs. 145 ± 128 ng ml(-1), respectively). sICAM-1 also increased with exercise, but similarly in M and HM (20 ± 40 vs. 23 ± 32 ng ml(-1), respectively). Only sICAM-1 remained elevated 28 h post-exercise in both HM and M, while IL-6, TNF-α, and MMP-9 returned to pre-exercise levels. Competitive HM and M races induce significant increases in IL-6, TNF-α, sICAM-1, and MMP-9 concentrations. As HM and M runners performed the competition with similar absolute intensity, the difference in response between the groups suggests that exercise duration is of importance in the regulation of IL-6, TNF-α, and MMP-9, but not sICAM-1 concentrations in response to prolonged running.

Enhanced arsenic removal by in situ formed Fe–Mn binary oxide in the aeration-direct filtration process

Field studies were conducted to evaluate the feasibility of an in situ formed Fe–Mn binary oxide (in situ FMBO) for improving arsenic (As) removal in the aeration-direct filtration process. The transformation and transportation of As, Fe, and Mn in the filter bed were also investigated. The in situ FMBO increased the As removal efficiency by 20–50% to keep the residual As below 10μg/L. The optimum FMBO dosage was determined to be 0.55mg/L with the Fe/Mn ratio as 10:1. The removal of Fe, Mn, turbidity, and particles was also improved to a large extent. The in situ FMBO favored the transformation of soluble As, Fe, and Mn into the solid phases, benefiting the removal of these pollutants by the subsequent filtration. Moreover, the deposited precipitates onto the filter media were characterized, as indicated by the analyses of SEM/EDS and particle size distribution. The long-term experiments exhibited decreased head loss growth and prolonged run length, suggesting an enhanced pollutant catching capacity of the filter media. The full-scale field study with a flow of 10,000m3/d confirmed positive effects of in situ FMBO on As removal, with the average effluent As concentration reduced from 20μg/L to 6μg/L (reagent cost=0.006¥/m3).