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PubMed2004

A new acceleration apparatus for the study of whiplash with human cadaveric cervical spine specimens.

The biomechanics of whiplash is often studied using cadaveric cervical spine specimens. One of the most important points in this kind of study is to create realistic loading conditions. The aim of the present project therefore was to develop an acceleration apparatus, which allows the study of whiplash with human cadaveric cervical spine specimens under as realistic loading conditions as possible. The new acceleration apparatus mainly consisted of a sled, a pneumatic acceleration unit and a railtrack and offered several unique features to create more realistic loading conditions. Among these features, the possibility to simulate the passive movements of the trunk is of capital importance. In this new apparatus, first, the general feasibility of whiplash experiments was studied, second, the reproducibility of the impacts was quantified and third, the effect of simulated movements of the trunk on accelerations and loads was examined. In the new acceleration apparatus various types of collisions could reproducibly be simulated. Simulated passive movements of the trunk strongly influenced the loading pattern of the neck. Without pivoting a steep increase of all loading parameters could be observed. This increase was less pronounced if pivoting was allowed. In conclusion, biomechanical aspects of whiplash could reproducibly be examined in the new acceleration apparatus. Due to its significant effects on the loading of the neck, pivoting of the trunk should always be taken into account in future experiments on the biomechanics of whiplash in which isolated cervical spine specimens are used.

Acceleration↗

PubMed2002

Static optimal estimation of joint accelerations for inverse dynamics problem solution.

In inverse dynamics computations, the accuracy of the solution strongly depends on the accuracy of the input data. In particular, estimated joint moments are highly sensitive to uncertainties in acceleration data. The aim of the present work was to improve classical inverse dynamics computations by providing an accurate estimation of accelerations. Accelerations are usually calculated from noise-polluted position data using numerical double differentiation, which amplifies measurement noise. The objective of the present paper is to use all available imperfect position and force measurements to extract optimum acceleration estimations. A weighted least-squares optimisation approach is used to provide optimal acceleration distributions most consistent with position and force data, and which account for the propagation of measurement uncertainties. The task chosen for comparing the solution methodology with other classical methods is a typical experimental postural movement, consisting in upper limb swings from an upright stance. The proposed method delivers a set of optimal accelerations well consistent with all available measurements. It also leads to an accurate prediction of ground reactions and it produces no residual moment at the top-most segment.

Acceleration↗

PubMed1999

A radiographic and tomographic imaging system integrated into a medical linear accelerator for localization of bone and soft-tissue targets.

PURPOSE: Dose escalation in conformal radiation therapy requires accurate field placement. Electronic portal imaging devices are used to verify field placement but are limited by the low subject contrast of bony anatomy at megavoltage (MV) energies, the large imaging dose, and the small size of the radiation fields. In this article, we describe the in-house modification of a medical linear accelerator to provide radiographic and tomographic localization of bone and soft-tissue targets in the reference frame of the accelerator. This system separates the verification of beam delivery (machine settings, field shaping) from patient and target localization. MATERIALS AND METHODS: A kilovoltage (kV) x-ray source is mounted on the drum assembly of an Elekta SL-20 medical linear accelerator, maintaining the same isocenter as the treatment beam with the central axis at 90 degrees to the treatment beam axis. The x-ray tube is powered by a high-frequency generator and can be retracted to the drum-face. Two CCD-based fluoroscopic imaging systems are mounted on the accelerator to collect MV and kV radiographic images. The system is also capable of cone-beam tomographic imaging at both MV and kV energies. The gain stages of the two imaging systems have been modeled to assess imaging performance. The contrast-resolution of the kV and MV systems was measured using a contrast-detail (C-D) phantom. The dosimetric advantage of using the kV imaging system over the MV system for the detection of bone-like objects is quantified for a specific imaging geometry using a C-D phantom. Accurate guidance of the treatment beam requires registration of the imaging and treatment coordinate systems. The mechanical characteristics of the treatment and imaging gantries are examined to determine a localizing precision assuming an unambiguous object. MV and kV radiographs of patients receiving radiation therapy are acquired to demonstrate the radiographic performance of the system. The tomographic performance is demonstrated on phantoms using both the MV and the kV imaging system, and the visibility of soft-tissue targets is assessed. RESULTS AND DISCUSSION: Characterization of the gains in the two systems demonstrates that the MV system is x-ray quantum noise-limited at very low spatial frequencies; this is not the case for the kV system. The estimates of gain used in the model are validated by measurements of the total gain in each system. Contrast-detail measurements demonstrate that the MV system is capable of detecting subject contrasts of less than 0.1% (at 6 and 18 MV). A comparison of the kV and MV contrast-detail performance indicates that equivalent bony object detection can be achieved with the kV system at significantly lower doses (factors of 40 and 90 lower than for 6 and 18 MV, respectively). The tomographic performance of the system is promising; soft-tissue visibility is demonstrated at relatively low imaging doses (3 cGy) using four laboratory rats. CONCLUSIONS: We have integrated a kV radiographic and tomographic imaging system with a medical linear accelerator to allow localization of bone and soft-tissue structures in the reference frame of the accelerator. Modeling and experiments have demonstrated the feasibility of acquiring high-quality radiographic and tomographic images at acceptable imaging doses. Full integration of the kV and MV imaging systems with the treatment machine will allow on-line radiographic and tomographic guidance of field placement.

Animals↗

PubMed1996

Load Acceleration and Footstep Strategies in Asymmetrical Lifting and Lowering.

Accelerated execution effects for lifting and lowering a 12-kg box using two footstep strategies associated with experienced workers were studied. Eight healthy male participants performed a normal and an accelerated execution of a lifting task and a lowering task, using a minimal feet displacement strategy (oblique-step) and a strategy with a step (crossed-step). It was hypothesized that the accelerated executions, as compared to the normal executions, would have a different effect on L5/S1 resultant moment, body posture, and other kinematic variables. A tridimensional dynamic rigid body model was used to compute L5/S1 resultant moments. Results showed that the accelerated condition did not reduce body asymmetry of posture, but it reduced the length of the path of the global center of gravity and the duration of the supporting phase of the box, and it did not significantly affect L5/S1 maximal resultant moments for lifting but increased them for lowering. These results indicate that the net work production for accelerated strategies might be smaller, which may represent an economy of energy. Furthermore, the results showed that the use of an accelerated strategy for lowering should be avoided.

acceleration↗

PubMed2006

Velocity encoding versus acceleration encoding for pressure gradient estimation in MR haemodynamic studies.

Many methods have been proposed to extract pressure gradient maps from magnetic resonance (MR) images. They were based on the resolution of the haemodynamic model of Navier-Stokes and needed the flow acceleration to be known. Most used velocity data acquisition and computed acceleration from temporal and spatial derivatives of the velocity field. However, MR sequences have been developed in order to acquire the acceleration field directly. Here we compared direct MR measurements of acceleration field components with those calculated from MR velocity acquisitions. Two experimental phantoms were used to separately evaluate the inertial and convective components of the acceleration. Mathematical simulation of the convective phantom further explained the origin of the noise generated by the spatial and temporal derivatives of the velocity data, and the misregistration artefacts due to MR sequences. We found that direct measurement of the acceleration field generates less noise and fewer artefacts than calculation from velocity derivatives.

Acceleration↗

PubMed2001

The history and future of accelerator radiological protection.

The development of accelerator radiological protection from the mid-1930s, just after the invention of the cyclotron, to the present day is described. Three major themes--physics, personalities and politics--are developed. In the sections describing physics the development of shielding design though measurement, radiation transport calculations, the impact of accelerators on the environment and dosimetry in accelerator radiation fields are described. The discussion is limited to high-energy, high-intensity electron and proton accelerators. The impact of notable personalities on the development of both the basic science and on the accelerator health physics profession itself is described. The important role played by scholars and teachers is discussed. In the final section. which discusses the future of accelerator radiological protection, some emphasis is given to the social and political aspects that must he faced in the years ahead.

History, 20th Century↗

PubMed2005

Transient, powerful pressures are generated in the brain by a rotational acceleration impulse to the head.

A rotational acceleration impulse to a head, as occurs at traffic accidents, sport injuries, assaults and falls, induces a diffuse brain damage that eventually could result in persistent neuropsychiatric deficits and neurodegeneration. Emphasis has been concentrated on the relative motion of the brain inside the skull during head impact, whereas less attention has been paid to whether intracranial pressure changes are generated and, if so, the implications thereof. In the present experimental study we investigated in an animal model system, based on rabbits, if a sagittal, anterior-posterior rotational acceleration of a head generated intracranial pressure changes, recorded by fibre optic pressure sensors, inserted ipsilaterally in the parieto-temporal and the occipital lobes. Two levels of rotational acceleration were used in the experiments; one higher, corresponding to the threshold limit for moderate diffuse brain injury, and one lower, close to being noninjurious. Several pressure recordings were performed in each rabbit at the two acceleration levels. The pressure recordings invariably revealed the same general characteristics of rapid, positive and negative pressures within the brain, with variations in amplitude and duration, lasting for up to 10 ms. A major finding was the generation of powerful negative pressures, as low as 0.3 bars in absolute pressure. The most prominent difference in amplitudes of the negative peak pressures between the two applied acceleration levels was demonstrated at the parieto-temporal location. The presented pressure recordings are the first to disclose the generation of transient, powerful intracerebral pressures at rotational acceleration of the head, which must be considered in studies of brain injury generation and distribution as well as prevention.

Acceleration↗

PubMed1975

Eye movements due to linear accelerations in the rabbit.

1. Compensatory vertical or torsional eye movements of rabbits caused by linear accelerations along the transverse or sagittal axis were measured. Sinusoidal accelerations (parallel swing) in a frequency range of 0-068--1-22 Hz and acceleration steps (linear track) of 0-02--0-11 g were applied. 2. On the parallel swing, properties of the maculo-ocular reflexes were similar for transverse and sagittal acceleration. Gain (rotation of eye/rotation of the resultant linear vector) proved to be very low: about 0-1 for 0-3 Hz and smaller than 0-01 for frequencies above 1-0 Hz. The decrease in gain was accompanied by an increase in phase lag to about 180degrees. No non-linearity was revealed by the use of different amplitudes (10--30 cm). 3. On the linear track, eye deviation after an acceleration step took many seconds to develop fully. Gain increased with time and was about 0-65 after 5 sec. 4. The results indicate that the responses of the otoliths, as reflected in maculo-ocular reactions, are very slow. Fluctuations in the direction of gravity seem to be averaged over several seconds by the system. This may explain that erratic linear accelerations(frequency greater than 1 Hz) during locomotion or transport do not lead to eye movements or disorientation.

Acceleration↗

PubMed1991

Pressure changes induced by whole body acceleration shocks.

In the present paper pressure changes induced by sudden body acceleration are studied "in vivo" on the dog and compared to the results obtainable with a recently developed mathematical model. A dog was fixed to a movable table, which was accelerated by a compressed air piston for less than 1 s. Acceleration was varied by changing the air pressure in the piston. Pressure was measured during the experiment at different points along the vascular bed. However, only data obtained in the carotid artery and abdominal aorta are presented here. The results demonstrated that impulse body accelerations cause significant pressure peaks in the vessel examined (about + 25 mmHg in the carotid artery with body acceleration of g/2). Moreover, pressure changes are rapidly damped, with a time constant of about 0.1s. From the present results it may be concluded that, according to the prediction of the mathematical model, body accelerations such as those occurring in normal life can induce pressure changes well beyond the normal pressure value.

Acceleration↗

PubMed2005

Determination of maximum leaf velocity and acceleration of a dynamic multileaf collimator: implications for 4D radiotherapy.

The dynamic multileaf collimator (MLC) can be used for four-dimensional (4D), or tumor tracking radiotherapy. However, the leaf velocity and acceleration limitations become a crucial factor as the MLC leaves need to respond in near real time to the incoming respiration signal. The aims of this paper are to measure maximum leaf velocity, acceleration, and deceleration to obtain the mechanical response times for the MLC, and determine whether the MLC is suitable for 4D radiotherapy. MLC leaf sequence files, requiring the leaves to reach maximum acceleration and velocity during motion, were written. The leaf positions were recorded every 50 ms, from which the maximum leaf velocity, acceleration, and deceleration were derived. The dependence on the velocity and acceleration of the following variables were studied: leaf banks, inner and outer leaves, MLC-MLC variations, gravity, friction, and the stability of measurements over time. Measurement results show that the two leaf banks of a MLC behave similarly, while the inner and outer leaves have significantly different maximum leaf velocities. The MLC-MLC variations and the dependence of gravity on maximum leaf velocity are statistically significant. The average maximum leaf velocity at the isocenter plane of the MLC ranged from 3.3 to 3.9 cm/s. The acceleration and deceleration at the isocenter plane of the MLC ranged from 50 to 69 cm/s2 and 46 to 52 cm/s2, respectively. Interleaf friction had a negligible effect on the results, and the MLC parameters remained stable with time. Equations of motion were derived to determine the ability of the MLC response to fluoroscopymeasured diaphragm motion. Given the present MLC mechanical characteristics, 4D radiotherapy is feasible for up to 97% of respiratory motion. For the largest respiratory motion velocities observed, beam delivery should be temporarily stopped (beam hold).

Algorithms↗

PubMed2006

Intraoperative radiation therapy using mobile electron linear accelerators: report of AAPM Radiation Therapy Committee Task Group No. 72.

Intraoperative radiation therapy (IORT) has been customarily performed either in a shielded operating suite located in the operating room (OR) or in a shielded treatment room located within the Department of Radiation Oncology. In both cases, this cancer treatment modality uses stationary linear accelerators. With the development of new technology, mobile linear accelerators have recently become available for IORT. Mobility offers flexibility in treatment location and is leading to a renewed interest in IORT. These mobile accelerator units, which can be transported any day of use to almost any location within a hospital setting, are assembled in a nondedicated environment and used to deliver IORT. Numerous aspects of the design of these new units differ from that of conventional linear accelerators. The scope of this Task Group (TG-72) will focus on items that particularly apply to mobile IORT electron systems. More specifically, the charges to this Task Group are to (i) identify the key differences between stationary and mobile electron linear accelerators used for IORT, (ii) describe and recommend the implementation of an IORT program within the OR environment, (iii) present and discuss radiation protection issues and consequences of working within a nondedicated radiotherapy environment, (iv) describe and recommend the acceptance and machine commissioning of items that are specific to mobile electron linear accelerators, and (v) design and recommend an efficient quality assurance program for mobile systems.

Electrons↗

PubMed2003

Shielding evaluation for IMRT implementation in an existing accelerator vault.

A formalism is developed for evaluating the shielding in an existing vault to be used for IMRT. Existing exposure rate measurements are utilized as well as a newly developed effective modulation scaling factor. Examples are given for vaults housing 6, 10 and 18 MV linear accelerators. The use of an 18 MV Siemens linear accelerator is evaluated for IMRT delivery with respect to neutron production and the effects on individual patients. A modified modulation scaling factor is developed and the risk of the incurrence of fatal secondary malignancies is estimated. The difference in neutron production between 18 MV Varian and Siemens accelerators is estimated using Monte Carlo results. The neutron production from the Siemens accelerator is found to be approximately 4 times less than that of the Varian accelerator resulting in a risk of fatal secondary malignancy occurrence of approximately 1.6% when using the SMLC delivery technique and our measured modulation scaling factors. This compares with a previously published value of 1.6% for routine 3D CRT delivery on the Varian accelerator.

Air Pollutants, Radioactive↗

PubMed2001

Muscle sympathetic outflow during horizontal linear acceleration in humans.

To elucidate the effects of linear acceleration on muscle sympathetic nerve activity (MSNA) in humans, 16 healthy men were tested in a linear accelerator. Measurements of MSNA, electrocardiogram, blood pressure, and thoracic impedance were undertaken during linear acceleration. Sinusoidal linear acceleration with peak values at +/-0.10, +/-0.15, and +/-0.20 G was applied in anteroposterior (+/-G(x), n = 10) or lateral (+/-G(y), n = 6) directions. The total activity and burst rate of MSNA decreased significantly during forward, backward, left, or right linear accelerations. The total activity of MSNA decreased to 50.5 +/- 6.9, 52.5 +/- 4.4, 71.2 +/- 9.6, and 67.6 +/- 8.2% from the baselines (100%) during linear accelerations with peak values at +/-0.20 G in the four directions, respectively. These results suggest that dynamic stimulation of otolith organs in horizontal directions in humans might inhibit MSNA directly in order to quickly redistribute blood to muscles during postural reflexes induced by passive movement, which supports the concept that the vestibular system contributes to sympathetic regulation in humans.

Acceleration↗

PubMed1975

Physiologic characteristics of vestibular first-order canal neurons in the cat. II. Response to constant angular acceleration.

The physiologic response of first-order vestibular canal neurons, recorded within the internal auditory canal with glass microelectrodes, was studied in anesthetized cats. Neurons from all three canals were subjected to velocity trapezoidal rotations about the canal axis, and about different axes extending up to 90 degrees on either side of the canal axis in "roll" and 30 degrees on either side of "pitch." Each cell examined exhibited a spontaneous discharge and responded to constant angular acceleration in a fashion predictable from the direction of the in-plane acceleration vector and the known receptor hair cell polarization. Under conditions of prolonged constant acceleration, (5 degrees/s2 for 40 s) about 30% of the units which could be classified showed adaptation, 55% did not, and 14%, termed reverse adapting cells, demonstrated a fast rise followed by a slower, continual increase during stimulation. Secondary responses (undershoot or overshoot) were noted in most adapting neurons, but were absent in the reverse adapting group. Adapting neurons were distinguished from the nonadapting group by significantly lower resting rates, more irregular interspike-interval distributions, and greater sensitivity to acceleration. When compared with nonadapting neurons, reverse adapting cells had higher spontaneous rates, less irregular spike intervals, and higher sensitivities. The mean canal sensitivity to angular acceleration for all cells was 2 spikes . s-1/deg . s-2 (range 0.3-7.4 spikes . s-1/deg . s-2). Significant differences in mean sensitivity values between canal neurons were demonstrated, with those from the anterior being the most sensitive, followed by the posterior and horizontal canals, respectively. Time constants for all canals governing the transitory rise (or fall) in rate with constant acceleration averaged 3.8 s. Small differences in mean values were noted between canals but these were not significant. Incremental time constants were found to be slightly but significantly longer (mean = 3.9 s) than decremental time constants (mean = 3.6 s). Some cells showed different tine constants to many trials of one stimulus as well as to different levels of stimulus. Most canal unitary responses were approximately linearly related to stimulus magnitudes over the range of 2-18 degrees/s2. This being the case, the angle between the canal plane and plane of stimulus become the main determinant in the first-order neural response. Here, a linear cosine relationship descriged the three-dimentionsal unitary response curve: maximum canal response was elicited with rotation about the canal axis, while no response was evoked with rotation about an axis approximately 90 degrees to canal axis. Between these two extremes, the response of a cell was determined by the cosine of the angle between the canala axis and the axis of rotation.

Acceleration↗

PubMed2003

Perceptual and oculomotor evidence of limitations on processing accelerating motion.

Psychophysical studies have demonstrated that humans are less sensitive to image acceleration than to image speed (e.g., Gottsdanker, 1956; Werkhoven, Snippe, & Toet, 1992). Because there is evidence that a common motion-processing stage subserves perception and pursuit (e.g., Watamaniuk & Heinen, 1999), either pursuit should be similarly impaired in discriminating acceleration or it must receive input from a system different from the one that processes visual motion for perception. We assessed the sensitivity of pursuit to acceleration or speed, and compared the results with those obtained in perceptual experiments done with similar stimuli and tasks. Specifically, observers pursued or made psychophysical judgments of targets that moved at randomly selected base speeds and subsequent accelerations. Oculomotor and psychophysical discrimination were compared by analyzing performance for the entire stimulus set sorted by either target acceleration or speed. Thresholds for pursuit and perception were higher for target acceleration than speed, further evidence that a common motion-processing stage limits the performance of both systems.

Acceleration↗

PubMed2005

Joint work and power associated with acceleration and deceleration in tammar wallabies (Macropus eugenii).

Measurements of joint work and power were determined using inverse dynamics analysis based on ground reaction force and high-speed video recordings of tammar wallabies as they decelerated and accelerated while hopping over a force platform on level ground. Measurements were obtained over a range of accelerations ranging from -6 m s(-2) to 8 m s(-2). The goal of our study was to determine which joints are used to modulate mechanical power when tammar wallabies change speed. From these measurements, we also sought to determine which hind limb muscle groups are the most important for producing changes in mechanical work. Because our previous in vivo analyses of wallaby distal muscle function indicated that these muscle-tendon units favor elastic energy savings and perform little work during steady level and incline hopping, we hypothesized that proximal muscle groups operating at the hip and knee joint are most important for the modulation of mechanical work and power. Of the four hind limb joints examined, the ankle joint had the greatest influence on the total limb work, accounting for 89% of the variation observed with changing speed. The hip and metatarsophalageal (MP) joints also contributed to modulating whole limb work, but to a lesser degree than the ankle, accounting for 28% (energy production) and -24% (energy absorption) of the change in whole limb work versus acceleration, respectively. In contrast, the work produced at the knee joint was independent of acceleration. Based on the results of our previous in vivo studies and given that the magnitude of power produced at the ankle exceeds that which these muscles alone could produce, we conclude that the majority of power produced at the ankle joint is likely transferred from the hip and knee joints via proximal bi-articular muscles, operating in tandem with bi-articular ankle extensors, to power changes in hopping speed of tammar wallabies. Additionally, over the observed range of performance, peak joint moments at the ankle (and resulting tendon strains) did not increase significantly with acceleration, indicating that having thin tendons favoring elastic energy storage does not necessarily limit a tammar wallaby's ability to accelerate or decelerate.

Acceleration↗

PubMed2006

Effect of fatigue on tibial impact accelerations and knee kinematics in drop jumps.

PURPOSE: The principle of specificity suggests that it may be beneficial to undertake plyometric drop-jump training when fatigued. However, this may increase peak-impact accelerations and therefore increase the risk of injury. The aims of the study were to determine if whole-body fatigue (i) increased peak-impact acceleration on the proximal tibia during plyometric drop jumps and (ii) produced associated changes in knee-joint kinematics during landing. METHODS: Fifteen physically active male subjects performed drop jumps (30 and 50 cm) when nonfatigued and when fatigued. Whole-body fatigue was induced using a treadmill running protocol that incrementally increased effort. Peak-impact acceleration was measured with an accelerometer attached to the proximal tibia. Knee-joint kinematics were assessed during the eccentric phase: angle at initial touch down, maximum angle of flexion, range of motion, and peak angular velocity. RESULTS: Fatigue caused a significant increase in tibial impact acceleration and peak angular velocity in drop jumps from 30 cm (154.9 +/- 93.8 vs 192.6 +/- 103.9 m x s(-2): 24%; 675.3 +/- 60.7 vs 811.4 +/- 68.9 degrees x s(-1): 20%), but not from 50 cm (222.4 +/- 74.9 vs 234.1 +/- 83.9 m x s(-2): 5%; 962.0 +/- 189.0 vs 984.4 +/- 189.3 degrees x s(-1): 2.6%), with no associated change in the knee-joint angles assessed. It was argued, however, that rather than the neuromuscular system being selectively affected by fatigue at 30 cm and not 50 cm, drop jumps from 50 cm resulted in larger-impact accelerations with the neuromuscular system having only a limited ability to attenuate them per se, whether fatigued or nonfatigued. CONCLUSION: Care should be taken when performing drop jumps from a height of 30 cm in a fatigued state because of the reduced capacity to attenuate impact accelerations at the tibia, which may be associated with an increased risk of injury.

Acceleration↗

PubMed2005

Nitric oxide is released into circulation with whole-body, periodic acceleration.

STUDY OBJECTIVE: To determine if comfortably applied, whole-body, periodic acceleration releases significant amounts of nitric oxide (NO) into the circulation of healthy subjects and patients with inflammatory diseases. MATERIALS: Fourteen healthy adults and 40 adult patients with inflammatory diseases underwent single 45-min trials of whole-body, periodic acceleration with a new "passive exercise" device, while an ECG and a digital pulse wave were obtained with a photoelectric-plethysmograph sensor. METHODS: The position of the dicrotic notch from the pulse waveform was computed from the amplitude of the pulse divided by the height of the dicrotic notch above the end-diastolic level (a/b ratio). Increase of the a/b ratio reflects the vasodilator action of NO that causes downward movement of the dicrotic notch in the diastolic limb of the digital pulse, thereby elevating the a/b ratio. RESULTS: Application of whole-body, periodic acceleration was well tolerated in all participants, and all completed the 45-min treatment. The peak value of the a/b ratio markedly rose during periodic acceleration and returned to baseline during a 5-min recovery period in all healthy subjects and patients with inflammatory diseases. CONCLUSIONS: Whole-body, periodic acceleration increased pulsatile shear stress to the endothelium leading to vasodilatation and a fall in the dicrotic notch, consistent with increased NO bioactivity in every healthy adult and adult patient with inflammatory disease so treated. Therefore, passive exercise using whole-body, periodic acceleration produces an important benefit that occurs with active exercise.

Acceleration↗