Two new Eimeria species parasitic in corncrakes (Crex crex) (Gruiformes: Rallidae) in the United Kingdom.

In this study we describe 2 new species of coccidia (Apicomplexa: Eimeriidae) parasites isolated from the feces of corncrake (Crex crex) (Gruiformes: Rallidae), bred in captivity in the U.K. Oocysts of Eimeria crecis n. sp. were approximately spherical and measured 15.3 µm (13-18) × 14.3 (12-16), providing an oocyst shape index of 1.1. A micropyle and oocyst residuum were absent, but a polar granule was present. Oocysts of Eimeria nenei n. sp. were ellipsoidal and measured 23.6 (21-26) × 18.1 (17-20), providing an oocyst shape index of 1.3. A micropyle and polar granule were present. Surveying free-living, wild adult corncrakes in Scotland (U.K.) demonstrated both parasite species to be widespread. These are the first species described to infect the corncrake, and they are distinct from those previously found to infect members of the closely related crane family (Gruiformes: Gruidae). Partial amplification and sequencing of the 18S rRNA gene and internal transcribed spacer 2 indicated a close relationship between the 2 proposed new species as a group distinct from the Eimeria species known to infect cranes. These newly identified parasite species have been associated with enteric disease in corncrakes being prepared for reproduction in captivity and reintroduction into England (U.K.).

Disseminated visceral coccidiosis in Eurasian cranes (Grus grus) in the UK.

Clinical disease and mortalities due to disseminated visceral coccidiosis were identified for the first time in a group of captive juvenile Eurasian cranes (Grus grus) in the UK during 2008. Presumptive diagnosis was made from the finding of granulomatous nodules in the liver, spleen and other organs at gross postmortem examination, and confirmed histologically by the presence of intracellular coccidial stages within lesions. The species of coccidian was determined to be Eimeria reichenowi on the basis of faecal oocyst morphology and sequencing of 18S rDNA by PCR. A further outbreak of clinical disease occurred in the same enclosure in 2009, affecting a new group of juvenile Eurasian cranes and demoiselle cranes (Anthropoides virgo) and indicating the persistence of infective oocysts in the environment. Clinical sampling of birds during both years demonstrated positive results from examination of both faecal samples and peripheral blood smears.

Dose-response effects of diclazuril against pathogenic species of ovine coccidia and the development of protective immunity.

Twin lambs at pasture with their ewes, were divided into seven groups of 10 lambs. One group of 10 lambs served as a non-infected, untreated control. Five groups of 10 lambs were infected with 10,000 oocysts of Eimeria crandallis and 10,000 oocysts of Eimeria ovinoidalis when they were 3 weeks old (day 21 of the study). This produced a good level of infection with high oocysts production and diarrhoea in the lambs. Fourteen days after the primary, artificial challenge (day 35) four of these groups were treated with oral diclazuril at 0.25, 1.0, 2.0 or 4.0mg/kg. Diclazuril treatment was highly effective, dramatically reducing symptoms of diarrhoea and reducing faecal oocyst output by 79.7%, 97.3%, 99.4% and 99.5% respectively in the treated groups within four days. Two weeks post-treatment, and 28 days after the primary coccidial challenge (day 49 of the study), five groups of lambs were re-challenged with 100,000 oocysts of E. crandallis and 100,000 oocysts of E. ovinoidalis (secondary challenge). A group of lambs which had received neither the primary coccidia infection, nor drug treatment (susceptible controls) were also given the secondary challenge. All lambs given the secondary challenge produced high numbers of coccidia and exhibited varying degrees of diarrhoeic faeces. The lambs, which had previously received the higher doses of diclazuril at 2.0 and 4.0mg/kg, developed clinical signs of coccidiosis. These lambs were completely susceptible despite having received the early primary immunising infection of coccidia on day 21. The effects of the secondary challenge were more severe in the groups dosed with the two highest levels of diclazuril than in the susceptible control lambs, which had presumably been exposed to continued low levels of pasture contamination and had acquired a limited degree of immunity from this exposure. It would appear that treatment at the higher dose levels not only eliminated most of the oocysts from the primary challenge but also adventitious infection derived from the grazing paddocks. In contrast, lambs which had received the two lower drug levels of diclazuril (0.25 and 1.0mg/kg) whilst producing large numbers of oocysts, had only transient diarrhoea following secondary challenge. It was concluded that when used as a metaphylactic treatment, diclazuril works rapidly and is effective within four days of administration. Overall, a single dose of diclazuril at either 0.25-1.0mg/kg appears to be highly effective in the control of coccidiosis in young lambs at pasture whilst allowing the development of protective immunity against subsequent heavy coccidia challenge.

Coccidian oöcysts as type-specimens: long-term storage in aqueous potassium dichromate solution preserves DNA.

Preservation of the exogenous oöcyst stage of coccidian parasites (phylum Apicomplexa N.D. Levine, 1970) as type-specimens of newly described species has long been problematical. Conventional fixatives have proved unsatisfactory, and compromises such as embedding oöcysts in resin or photographing them are not entirely appropriate for various reasons. As an alternative, chilled potassium dichromate solution (normally used in the laboratory to prevent putrefaction of temporary preparations of live oöcysts) has been tested as a long-term preservative of sporulated oöcysts of Eimeria brunetti P.P. Levine, 1942, E. maxima Tyzzer, 1929, E. mitis Tyzzer, 1929, E. necatrix Johnson, 1930, E. praecox Johnson, 1930 and E. tenella (Railliet & Lucet, 1891) (suborder Eimeriorina Léger, 1911; family Eimeriidae Minchin, 1903). Oöcysts from faeces of chickens Gallus gallus (Linnaeus) were placed in 2.5% w/v aqueous potassium dichromate solution (PDS) and stored in the dark at 4 +/- 2 degrees C. After 23 years in storage, oöcysts of each species were administered orally to chickens and failed to initiate infections, indicating that the oöcysts were dead. Nevertheless, after about 24 years, DNA was still recoverable from the oöcysts, and the original species identifications made by classic parasitological methods were confirmed by polymerase chain reaction assays. Furthermore, after almost 25 years, microscopical examination revealed that the walls and internal structures remained well preserved in 83-98% of the oöcysts of the six species investigated. Hence, PDS is potentially suitable for the long-term preservation of sporulated coccidian oöcysts as type-specimens for taxonomic purposes. The samples used in this study are now in the care of the Natural History Museum, London, UK. It is recommended that they be monitored in like manner, by suitably qualified scientists, at intervals of about 5 years to assess their state of preservation and the recoverability of DNA. Enough material is available to monitor it until it is at least 100 years old.

Isosporoid coccidiosis in translocated cirl buntings (Emberiza cirlus).

Four of 17 cirl buntings (Emberiza cirlus) involved in a trial translocation in 2004 for conservation purposes died and were examined postmortem. Two of the cirl buntings showed intestinal and hepatic lesions, including necrotising enteritis, consistent with isosporoid coccidiosis, and a third had an intestinal infestation of isosporoid coccidia. Sporulated oocysts from faecal samples from the birds were identified as Isospora normanlevinei, a parasite previously detected in cirl bunting populations in continental Europe. In a subsequent translocation of 75 cirl buntings from Devon to Cornwall in 2006, each brood of birds was placed in strict quarantine at low stocking density, with improved hygienic precautions and detailed health surveillance, and each bird was treated prophylactically with toltrazuril in an attempt to control the disease but not eliminate the I normanlevinei parasites. Seventy-two of the 75 birds were successfully reared and released, and there were no apparent clinical or pathological signs of isosporoid coccidiosis in any bird. I normanlevinei was detected in the released population, an indication that it had been successfully conserved.

Pathogenesis of Eimeria praecox in chickens: virulence of field strains compared with laboratory strains of E. praecox and Eimeria acervulina.

The pathogenesis in chickens of the apicomplexan Eimeria praecox was compared with that of Eimeria acervulina, using intestinal lesions, mucosal integrity, body weight gain (BWG) and the feed conversion ratio (FCR) as criteria. Characteristics of each species were described by combinations of polymerase chain reaction assays and classic parasitological signs. There were considerable overlaps in lengths, breadths, shape indices and volumes of the oocysts of each species. Both species caused statistically significant reductions in BWG at the lowest inocula tested (500,000 sporulated oocysts per bird of E. praecox and 250,000 of E. acervulina). E. praecox was observed for the first time to cause actual body weight loss and marked increases in FCR, as did E. acervulina. E. acervulina caused gross, white pathognomonic lesions, but E. praecox caused micro-lesions, visible in fresh tissue only with a dissecting microscope. Occasionally, lesions of the Houghton strain of E. acervulina were observed to be rounded, rather than typically "ladder-like". Both species caused villous erosion and atrophy. No mortality occurred in birds receiving up to 1 million sporulated oocysts of either species. Using BWG and FCR as criteria, the virulence of recent field strains of E. praecox from Wales (Tynygongl) and the USA (Raleigh) was compared with English laboratory strains of E. praecox (Houghton) and E. acervulina (Houghton). E. praecox (Tynygongl) was markedly more virulent than E. acervulina (Houghton), which was more virulent than E. praecox (Raleigh) and E. praecox (Houghton).

Three-dimensional lumbar segment kinetics of fast bowling in cricket.

Cricket fast bowlers have a high incidence of serious lumbar injuries, such as lesions in the pars interarticularis. Kinematic studies have shown that bowling actions with large shoulder counter-rotation are associated with significantly higher incidences of lumbar injury. However, in bowling, there has been no calculation of the spinal loads, which are the causal mechanisms of such injuries. In this study, 21 fast bowlers (22.4+/-3.9 years) of premier grade level and above were tested using a three-dimensional (3D) motion analysis system. The mean ball release speed was 31.9+/-2.8 m s(-1) and ranged from 27.0 to 35.6 m s(-1). Kinematics and kinetics were calculated for lumbar spine lateral bending, rotation, and flexion during the delivery and power phases of bowling. Power calculations were used to define the actuation of lumbar spine motion as either active or controlled. The actuation of the lumbar spine was complex, involving multiple sequences of active and controlled motion. In addition, lumbar spine loads were largest during the power phase when the ground reaction forces were highest. In conclusion, the dynamic loads and the cyclical nature of their application when the spine is positioned near its end range of motion may be significant factors of injury to this region. In addition, the lumbar spine in bowling has to vigorously flex, laterally bend and rotate simultaneously in a complex interdependent sequence of actuation patterns. Therefore, any technical change to reduce injury susceptibility needs to consider the mechanics of whole body coordination and timing.

Cryptosporidium parvum infection in orphan lambs on a farm open to the public.

A longitudinal survey was undertaken on an open farm to investigate the occurrence of Cryptosporidium species infection in orphan lambs obtained from three local flocks. During an initial pilot study, Cryptosporidium oocysts were detected by a fluorescent antibody test (fat) in the faeces of two of 21 lambs aged between one and three weeks derived from one flock (flock A). Pooled pen samples of faeces were collected weekly from lambs derived from each flock; oocysts were detected by fat in 24 (49.0 per cent) of 49 samples from lambs from flock A, 18 (30.5 per cent) of 59 samples from lambs from flock B and 14 (29.8 per cent) of 47 samples from lambs from flock C. Oocyst counts of 1 x 10(3) to more than 2 x 10(6) per gram of faeces were detected in lambs up to 12 weeks old, with the peak counts occurring at six weeks of age in the lambs from flocks A and B and at four weeks of age in those from flock C. The oocysts were confirmed by molecular analysis as Cryptosporidium parvum. Virtually all the infections were subclinical.

Influence of colostrum deprivation and concurrent Cryptosporidium parvum infection on the colonization and persistence of Escherichia coli O157 : H7 in young lambs.

Escherichia coli O157 : H7 and Cryptosporidium parvum infections of man have been associated with direct contact with small ruminants. Colostrum protects neonates against gastrointestinal pathogens, and orphan lambs, which are common on petting farms, may be deprived of this protection. In a recent study, it was demonstrated that high shedding of E. coli O157 : H7 by an 8-week-old goat kid was associated with coincidental C. parvum infection. Furthermore, both pathogens were co-located in the distal gastrointestinal tract. It was hypothesized that colostrum deprivation and pre-infection with C. parvum predisposed young ruminants to colonization and increased shedding of E. coli O157 : H7. To test this, 21 lambs 5 weeks of age were divided into four groups as follows: (A) colostrum-deprived and inoculated with E. coli O157 : H7, (B) colostrum-deprived and inoculated with C. parvum and then E. coli O157 : H7, (C) conventionally reared and inoculated with E. coli O157 : H7, (D) conventionally reared and inoculated with C. parvum and then E. coli O157 : H7. C. parvum was detected between 8 and 12 days post-inoculation in most of the infected lambs. At 24 h post-inoculation with E. coli O157 : H7, all lambs were shedding between 5 x 10(4) and 5 x 10(7) c.f.u. E. coli O157 : H7 per gram of faeces. E. coli O157 : H7 was shed in higher numbers in the groups pre-inoculated with C. parvum, whether conventionally reared or colostrum-deprived. Interestingly, for the colostrum-deprived lambs on day 3, a significant difference in shedding of E. coli O157 : H7 was observed (P = 0.038), with the lambs inoculated with E. coli alone yielding higher counts than those pre-inoculated with C. parvum. From day 15 onwards, shedding of E. coli O157 : H7 was highest from the colostrum-deprived C. parvum-infected lambs, then (in descending order of shedding) the colostrum-deprived lambs, the conventionally reared lambs infected with C. parvum, and the conventionally reared animals. In total, four animals were euthanized, two at 24 h and two at 96 h post inoculation with E. coli O157 : H7 (two conventionally reared and two colostrum-deprived). All animals euthanized were from groups pre-inoculated with C. parvum prior to challenge with E. coli O157 : H7. On examination of tissues, in three of the four animals examined, multifocal attaching and effacing lesions were observed in the caecum, colon, rectum and at the recto-anal junction, and were confirmed by immunohistochemistry to be associated with E. coli O157 : H7.

A kinematic, kinetic and electromyographic comparison of stooped sheep shearing techniques and shearing with a sheep manipulator.

Traditional sheep shearing methods require workers to adopt postures where the trunk is approximately horizontal and held in that position against gravity for long periods of time. The objective of this study was to examine the biomechanics of stooped shearing techniques and to compare the effectiveness of a new sheep manipulator in reducing the frequency of these postures and the changes in low back forces and electromyographic (EMG) activity. Five male shearers were filmed using three video cameras and EMG and three-dimensional (3D) kinematic data were derived during seven segments of the shearing action. Kinematic data were used to calculate the L5/S1 compressive and shear forces using the 3D Static Strength Prediction Program(TM). Results showed the low back forces in stooped shearing were typically between 2200 and 3000N. Also, the sheep manipulator effectively allowed the shearers to maintain a more upright posture (mean trunk angle >65 degrees) which decreased the compressive (maximum <1350N) and shear (maximum <260N) forces at L5/S1.

Histopathological observations on the activity of diclazuril (Vecoxan) against the endogenous stages of Eimeria crandallis in sheep.

Doses of sporulated oocysts of Eimeria crandallis were administered to 60 housed lambs aged 3-4 weeks that had been raised coccidia-free. Thirty of the lambs were medicated with diclazuril at intervals over a 20-day period post-infection with the remaining lambs serving as untreated controls. Lambs were euthanased between 5 and 22 days post-infection (dpi) and sections of the small intestine and caecum examined histologically. Untreated lambs showed loss of surface epithelial cells and villous atrophy associated with first-generation meronts, crypt destruction and crypt hyperplasia associated with pro-gamont stages. Diclazuril appeared to have a direct effect on several stages of the parasite life cycle, in particular, the large first-generation meront. Indications were that the drug also had an effect on second-generation meronts and gamont stages. Therapeutic benefits of diclazuril treatment appeared greatest when given early in the infection before damage to the intestine occurs although removal of coccidial stages did appear to reduce the pathology of the disease.

A new method for the experimental production of necrotic enteritis and its use for studies on the relationships between necrotic enteritis, coccidiosis and anticoccidial vaccination of chickens.

A new method for the experimental production of necrotic enteritis in chickens is described. The main features are the use of a diet high in wheat and fish meal content; oral administration of a non-lethal inoculum of the coccidium Eimeria maxima followed 6 days later by the bacterium Clostridium perfringens type A per cloaca, so that the bacterial inoculum is deposited at the time and place when and where the intestinal coccidial lesions are maximal; grading of coccidial and clostridial lesions in individual birds sampled during the 14 days following the coccidial infection. The new method was used to examine the relationship between clostridial and coccidial infections. Frank coccidiosis, caused by virulent E. maxima, exacerbated the lesions of necrotic enteritis and other clinical effects due to a subsequent challenge with virulent C. perfringens type A. Immunization with a live, pentavalent, attenuated anticoccidial vaccine (Paracox-5) protected against a severe challenge with heterologous E. maxima. Furthermore, vaccination with Paracox-5, by virtue of its protection against clinical coccidiosis due to the E. maxima challenge, indirectly protected birds against a subsequent challenge with virulent C. perfringens. The results are reconciled with previous field observations on concomitant coccidiosis and necrotic enteritis in chicken flocks.

Is velocity-specific strength training important in improving functional performance?

A variable considered when designing programs to optimize athletic performance is training velocity. It has been suggested that training at a specific velocity improves strength mainly at that velocity and as velocity deviates from the trained velocity, the less effective training will be. However, the research describing velocity-specific adaptation and the transference of these adaptations to other movement velocities is by no means clear. Compounding the problem in this area is the failure of research to detail the relationship between training velocity and actual movement velocity of a given task or athletic pursuit. In most cases there is a great disparity between training velocity and actual movement velocity. Factors that may better develop and explain velocity-specific adaptation in relation to functional performance are discussed. Developing qualities such as strength, power and rate of force development would appear of greater importance than training at the actual movement velocity of a task. It may be that irrespective of load and limb velocity, the repeated intent to move an isoinertial load as rapidly as possible might be an important stimulus for functional high velocity adaptation. The ability of the nervous system to activate and coordinate agonist, synergist and antagonist activity would seem essential. It was suggested training techniques that simulate the velocity and acceleration profiles associated with the desired functional performance, such as throw or jump training, may optimize functional adaptation. Furthermore combination training that incorporates same session sport specific training with either a heavy load or a mixed training load approach might provide an optimal strategy for promoting intramuscular and intermuscular co-ordination and improving functional performance.

Velocity specificity, combination training and sport specific tasks.

Whether velocity-specific resistance training is important for improving functional sporting performance was investigated by studying the effect of isoinertial training velocity on netball chest pass throwing velocity. Twenty-one female netball players were randomly assigned to a strength-trained group (80% 1RM - average training velocity = .308 m/s), power-trained group (60% 1RM - average training velocity = .398 m/s) and a control group. Resistance training was combined with sport specific motion training for both groups over a ten-week training duration. Pre- and post-training testing revealed that the training velocity associated with the strength-trained group produced significantly greater improvement in mean volume of weight lifted (85kg) and mean power output (13.25 W) as compared to the power and control groups (P< 0.05). The strength-trained and power-trained groups significantly improved netball throw velocity by 12.4% and 8.8% respectively. There was no significant difference between the two groups. The validity of velocity-specific training and subsequent adaptations to improve functional sporting performance appears highly questionable, due to the disparity between training velocity and actual movement velocity (11.38 m x s(-1)) for a given sport specific task such as the netball throw it was proposed that the repeated intent to move an isoinertial load as rapidly as possible coupled with performance of the sport-specific movement promote efficient coordination and activation patterns. Such mechanisms might be more important determinants of sport-specific high velocity adaptation.

Magnitude and decay of stretch-induced enhancement of power output.

There is ample evidence that the pre-stretching of a muscle enhances performance of the subsequent shortening or concentric contraction. The purpose of this study was to investigate this stretch-induced enhancement in terms of the effect of load on the magnitude and decay of the muscle's power output. Instantaneous, mean and peak power outputs were compared between concentric-only and rebound bench press throws at different loads. The maximal strength [1 RM = 84.0 (10.5) kg] of 18 male subjects [21.1 (3.0) years, 87.2 (11.9) kg] was determined using an isoinertial Smith press machine. The results of this study indicate enhancement of concentric motion by prior eccentric muscle action (200-780% enhancement in the first 100 ms). However, the magnitude and temporal characteristics of this enhancement differed across loads. Using a lighter load produced greater initial enhancement (P < 0.05) but the decay of this enhancement was more rapid. The heavier 80% 1 RM loading showed a later time to peak enhancement (80 ms versus 20 ms) and slower decay of the stretch induced augmentation (460 ms versus 260 ms). It is concluded that the degree of stretch-shorten cycle enhancement differs according to the load and the time-dependent characteristics of the motion.

The effect of aircraft control forces on pilot performance during instrument landings in a flight simulator.

BACKGROUND: Pilots may have difficulty controlling aircraft at both high and low force levels due to larger variability in force production at these force levels. The aim of this study was to measure the force variability and landing performance of pilots during an instrument landing in a flight simulator. METHODS: There were 12 pilots who were tested while performing 5 instrument landings in a flight simulator, each of which required different control force inputs. Pilots can produce the least force when pushing the control column to the right, therefore the force levels for the landings were set relative to each pilot's maximum aileron-right force. The force levels for the landings were 90%, 60%, and 30% of maximal aileron-right force, normal force, and 25% of normal force. Variables recorded included electromyographic activity (EMG), aircraft control forces, aircraft attitude, perceived exertion and deviation from glide slope and heading. Multivariate analysis of variance was used to test for differences between landings. RESULTS: Pilots were least accurate in landing performance during the landing at 90% of maximal force (p < 0.05). There was also a trend toward decreased landing performance during the landing at 25% of normal force. Pilots were more variable in force production during the landings at 60% and 90% of maximal force (p < 0.05). CONCLUSION: Pilots are less accurate at performing instrument landings when control forces are high due to the increased variability of force production. The increase in variability at high force levels is most likely associated with motor unit recruitment, rather than rate coding. Aircraft designers need to consider the reduction in pilot performance at high force levels, as well as pilot strength limits when specifying new standards.

Developing explosive power: a comparison of technique and training.

The influence of contraction type and movement type on power output of the upper body musculature was investigated across loads of 30-80% 1RM. Twenty seven males (21.9+/-3.1 years, 89.0+/-12.5 kg, 86.32+/-13.66 kg 1RM) of an athletic background but with no weight training experience in the previous six months volunteered for the study. The results were compared using multivariate analysis of variance with repeated measures (p< or =0.05). It was found that the combinations of load, movement and contraction type affected mean and peak power in different capacities. Mean power output for rebound motion was 11.7% greater than concentric only motion. The effect of the rebound was to produce greater peak accelerations (38.5%--mean across loads), greater initial force and peak forces (14.1%--mean across loads) and early termination of the concentric phase. Peak power output was most influenced by the ability to release the bar, the greater mean velocities across all loads (4.4% average velocity and 6.7% peak velocity) attained using such a technique appeared the dominating influence. Loads of 50-70% 1RM were found to maximize mean and peak power. Loading the neuromuscular system to maximize mean or peak power output necessitates an understanding of the force-velocity characteristics of the training movement and the requirements of the individual related to the athletic performance and their training status.

Aircraft control forces and EMG activity: comparison of pilots before and after flying training.

BACKGROUND: Skilled performers in most motor tasks tend to require less force, muscle activity, and co-contraction of agonist and antagonist muscles to complete tasks. There have been two previous studies on muscle activation patterns and applied forces of skilled and novice pilots, but no longitudinal measurements have been made. The aim of this study was to compare the muscle activation patterns of pilots who had recently completed pilot training with those of experienced pilots. A secondary aim of the study was to examine co-contraction of novice and experienced pilots. METHODS: Novice (n = 12) and experienced (n = 9) pilots were tested on an Aermacchi flight simulator. The novice pilots were tested before and after completing pilot training. Pilots performed a set of landings, rolls, and turns, which were administered in a random order. Variables recorded included aircraft attitude, pilot applied forces, and electromyographic (EMG) activity. Discriminant function analysis was used to classify pilots as novice or experienced. RESULTS: Muscle activation patterns of the novice pilots after completion of pilot training were similar to those of experienced pilots. Of the recently graduated pilots, 77% were classified as experienced using discriminant function analysis. The maneuver in which the recently graduated pilots most closely resembled experienced pilots was the left aileron roll. During this maneuver, experienced and recently graduated pilots showed lower levels of co-contraction than novice pilots (p < 0.05). CONCLUSION: The similarities in some muscle activity patterns across qualified pilots, regardless of experience level, may be useful in initiating protective systems such as G-suit inflation.

Aircraft control forces and EMG activity in a C-130 Hercules during strength-critical maneuvers.

BACKGROUND: The force levels required to operate aircraft controls should be readily generated by pilots, without undue fatigue or exertion. However, maximum pilot applied forces, as specified in aircraft design standards, were empirically derived from the subjective comments of test pilots, and may not be applicable for the majority of pilots. Further, experienced RNZAF Hercules flying instructors have indicated that endurance and fatigue are problems for Hercules pilots. The aim of this study was to quantify aircraft control forces during emergency maneuvers in a Hercules aircraft and compare these forces with design standards. In addition, EMG data were recorded as an indicator of muscle fatigue during flight. METHODS: Six subjects were tested in a C-130 Hercules aircraft. The maneuvers performed were low-level dynamic flight, one engine-off straight-and-level flight, and a two-engines-off simulated approach. The variables recorded were pilot-applied forces and EMG activity. RESULTS: Left rudder pedal force and vastus lateralis activity were both significantly greater during engine-off maneuvers than during low-level dynamic flight (p < 0.05). Maximum aircraft control forces for all controls were within 10% of the design standards. The mean EMG activity across all muscles and maneuvers was 26% MVC, with a peak of 61% MVC in vastus lateralis during the two-engine-off approach. The median frequency of the vastus lateralis EMG signal decreased 13.0% and 16.0% for the one engine-off and two-engine-off maneuvers, respectively. CONCLUSION: The forces required to fly a Hercules aircraft during emergency maneuvers are similar to the aircraft design standards. However, the levels of vastus lateralis muscle activation observed during the engine-off maneuvers can be sustained for approximately 1 min only. Thus, if two engines fail more than 1 min before landing, pilots may have to alternate control of the aircraft to share the workload and enable the aircraft to land safely.