Soft Tissue Vibrations Research Articles

The role of impact forces and foot pronation: a new paradigm.

This article discusses the possible association between impact forces and foot pronation and the development of running-related injuries, and proposes a new paradigm for impact forces and foot pronation. The article is based on a critical analysis of the literature on heel-toe running addressing kinematics, kinetics, resultant joint movements and forces, muscle activity, subject and material characteristics, epidemiology, and biologic reactions. However, this paper is not a review of the literature but rather an attempt to replace the established concepts of impact forces and movement control with a new paradigm that would allow explaining some of the current contradictions in this topic of research. The analysis included all papers published on this topic over the last 25 years. For the last few years, it concentrated on papers expressing critical concerns on the established concepts of impact and movement control. An attempt was made to find indications in the various publications to support or reject the current concept of impact forces and movement control. Furthermore, the results of the available studies were searched for indications expanding the current understanding of impact forces and movement control in running. Data were synthesized revealing contradictions in the experimental results and the established concepts. Based on the contradictions in the existing research publications, a new paradigm was proposed. Theoretical, experimental, and epidemiological evidence on impact forces showed that one cannot conclude that impact forces are important factors in the development of chronic and/or acute running-related injuries. A new paradigm for impact forces during running proposes that impact forces are input signals that produce muscle tuning shortly before the next contact with the ground to minimize soft tissue vibration and/or reduce joint and tendon loading. Muscle tuning might affect fatigue, comfort, work, and performance. Experimental evidence suggests that the concept of "aligning the skeleton" with shoes, inserts, and orthotics should be reconsidered. They produce only small, not systematic. and subject-specific changes of foot and leg movement. A new paradigm for movement control for the lower extremities proposes that forces acting on the foot during the stance phase act as an input signal producing a muscle reaction. The cost function used in this adaptation process is to maintain a preferred joint movement path for a given movement task. If an intervention counteracts the preferred movement path, muscle activity must be increased. An optimal shoe, insert, or orthotic reduces muscle activity. Thus, shoes, inserts, and orthotics affect general muscle activity and, therefore, fatigue, comfort, work, and performance. The two proposed paradigms suggest that the locomotor system use a similar strategy for "impact" and "movement control." In both cases the locomotor system keeps the general kinematic and kinetic situations similar for a given task. The proposed muscle tuning reaction to impact loading affects the muscle activation before ground contact. The proposed muscle adaptation to provide a constant joint movement pattern affects the muscle activation during ground contact. However, further experimental and theoretical studies are needed to support or reject the proposed paradigms.

Impact forces and muscle tuning: a new paradigm.

Impact forces and muscle tuning: a new paradigm. Exerc. Sport Sci. Rev., Vol. 29, No. 1, pp 37-41, 2001. We propose that repetitive impact forces during physical activities are not important from an injury perspective but are the reason for changes in myoelectric activity (muscle tuning) to minimize soft tissue vibrations. Changes in myoelectric activity (intensity, frequency, timing), comfort, and performance provide supporting evidence for this new paradigm.

Elastographic imaging

Elastographic imaging

The Effectiveness of Soft Tissue Vibration in Reducing Pain of Local Anesthesia Injection in Adult Dental Patients

The Effectiveness of Soft Tissue Vibration in Reducing Pain of Local Anesthesia Injection in Adult Dental Patients

Shoe inserts and orthotics for sport and physical activities.

The purposes of this paper were to discuss the perceived benefits of inserts and orthotics for sport activities and to propose a new concept for inserts and orthotics. There is evidence that inserts or orthotics reduce or prevent movement-related injuries. However, there is limited knowledge about the specific functioning an orthotic or insert provides. The same orthotic or insert is often proposed for different problems. Changes in skeletal movement due to inserts or orthotics seem to be small and not systematic. Based on the results of a study using bone pins, one may question the idea that a major function of orthotics or inserts consists in aligning the skeleton. Impact cushioning with shoe inserts or orthotics is typically below 10%. Such small reductions might not be important for injury reduction. It has been suggested that changes in material properties might produce adjustments in the muscular response of the locomotor system. The foot has various sensors to detect input signals with subject specific thresholds. Subjects with similar sensitivity threshold levels seem to respond in their movement pattern in a similar way. Comfort is an important variable. From a biomechanical point of view, comfort may be related to fit, additional stabilizing muscle work, fatigue, and damping of soft tissue vibrations. Based on the presented evidence, the concept of minimizing muscle work is proposed when using orthotics or inserts. A force signal acts as an input variable on the shoe. The shoe sole acts as a first filter, the insert or orthotic as a second filter, the plantar surface of the foot as a third filter for the force input signal. The filtered information is transferred to the central nervous system that provides a subject specific dynamic response. The subject performs the movement for the task at hand. For a given movement task, the skeleton has a preferred path. If an intervention supports/counteracts the preferred movement path, muscle activity can/must be reduced/increased. Based on this concept, an optimal insert or orthotic would reduce muscle activity, feel comfortable, and should increase performance.

A Randomized Double-Blind Placebo-Controlled Evaluation of the Safety and Efficacy of a Natural Over-The-Counter (OTC) Medication in the Management of Snoring.

More than 40 million American adults snore. Habitual snoring afflicts 44% of adult males and 28% of females.(1) Uncomplicated snoring is generally due to vibration of the palatal soft tissues or the tongue base, causing intermittent airway obstruction. Loudness is correlated with the degree of vibration and/or obstruction. The tendency, frequency, duration, intensity, and sequelae of snoring are influenced by myriad structural, physiological, environmental and pharmacological factors. Uncomplicated, nonapneic snoring is treated in a wide variety of ways, ranging from self-help methods, such as positional therapy, to laser surgery. The purpose of this report is to evaluate the safety and efficacy of a natural medication for snoring in a randomized double-blind placebo-controlled trial. The treatment is significantly more effective than placebo. Neither side effects nor intolerance to the product was reported.

Quantitative surface electromyography for clinical gait analysis

The purpose of this study was to quantify the effects of selected foot orthoses on muscle activity in the lower extremity during running. Nine male and 12 female recreational runners, clinically and functionally classified as ‘pronators’, volunteered for this study and performed over-ground running trials at 4 m/s in each of four experimental conditions: control, posting, molding, and posting & molding. Electromyographic (EMG) signals were recorded from seven lower extremity muscles. Wavelet analysis was performed to obtain EMG intensities in two frequency bands that were averaged for the pre-heel-strike and post-heel-strike intervals and for 30–100% of stance phase. Posting and custom-molding of foot orthoses increased the global EMG intensity of most muscles of the lower extremity for the stance phase of running (P < 0.05). The increases in EMG intensity were greater in the high- than in the low-frequency bands for some lower extremity muscles (P < 0.05). The effects on muscle activity of posting and custom-molding of foot orthoses differed between the three phases of running gait. The three tested foot orthoses did affect lower extremity muscle activity differently and these effects were specific to the phases of running gait. Combinations of increased requirements of controlling joint motion and minimizing soft tissue vibrations may have led to greater increases in shank muscle activity for the posted condition. The substantial changes in EMG due to orthotic interventions found in this study documents the importance of the study of muscle activity as a reaction to shoe inserts and foot orthoses.

Snoring and sleep apnea syndrome: surgical treatment and MESAM-IV controlled, postoperative results

Approximately 20% of the population snore. Snoring is caused by a vibration of oropharyngeal soft tissues during air flow. The anatomical origin of snoring can be the soft palate with a hyperplastic uvula or the region of the base of tongue. An uvulopalatopharyngoplasty (UPPP) as a mode of surgical treatment is only appropriate in the first case. A patient can be considered to be suffering from sleep apnea syndrome if snoring is associated with a temporary complete obstruction of the upper airway with a subsequent decrease in oxygen saturation. In this case continuous positive airway pressure (CPAP) therapy can be beneficial; however, the role of surgery is confined to those operations providing unimpaired nasal air flow. Following extensive preoperative diagnostics, including sleep monitoring with the MESAM-IV-system, 68 patients with palatal snoring underwent surgery. 46 could be examined 6 to 8 months postoperatively: In 41 patients snoring disappeared completely or was reduced to a few occasional episodes. 5 patients continued to snore after the UPPP. These patients were obese at the time of surgery and a preoperative attempt to lose weight was only partially successful. Although we identified the soft palate as the probable cause of snoring by fiberoptic examination, especially the overweight patients bear the risk of additional narrow segments in the region of the base of the tongue. The appropriate weight loss is therefore a fundamental prerequisite for successful treatment. 5 patients with sleep apnea syndrome combined with nasal obstruction underwent septum, turbinate and sinus surgery to create unobstructed nasal airflow. The following CPAP treatment was of great benefit to them.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of continuous wave ultrasound for measurement of the dynamic response of soft tissue to facilitate diagnosis of disease

A noninvasive, noncontact ultrasonic system for measurement of amplitudes of vibration of soft tissue has been developed for operation in air. The measurement method, based on phase modulation of low power, continuous wave ultrasound, was originally developed by Rogers and Hastings [U.S. Patent No. 4,819,643 (11 April 1989)] to measure the frequency response of auditory organs in fish underwater. In this study, the technique was used to measure the response of corneas of enucleated bovine eye globes to acoustic excitation at audible frequencies in air. Data were recorded at different levels of intraocular pressure (IOP) which is routinely clinically measured to screen for glaucoma. A mathematical model for harmonic motion of the corneal shell was developed for correlation with empirical results. The stiffness and natural frequency of the thin corneal shell are functions of IOP; thus the data provide a noncontact measurement of this parameter. This ultrasonic measurement technique eliminates the problems associated with current contact tonometry methods which include maintaining sterility, abrading the corneal surface, and inherently altering the IOP. [Work supported by NSF Grant No. MSS 9058607.]

Ultrasonic imaging of internal vibration of soft tissue under forced vibration

An imaging system that can display both the amplitude and phase maps of internal vibration in soft tissues for forced low-frequency vibration is described. In this method, low-frequency sinusoidal vibration of frequency under several hundred hertz is applied from the surface of the sample and the resulting movement in it is measured from the Doppler frequency shift of the simultaneously transmitted probe ultrasonic waves. Basic experiments are carried out by using 3.0-MHz ultrasonic waves. The two-dimensional maps of the amplitude and phase of internal vibration are shown, and the velocities of vibration are measured for some samples as well as in vivo.

Ultrasonic imaging of the internal vibration of soft tissue under forced vibration

To estimate the dynamic properties of soft tissues, an imaging system that can display both the amplitude and phase distributions of vibration in soft tissues under forced vibration was developed. In this method, low-frequency sinusoidal vibration with a frequency from 10 Hz to 1 kHz is applied from the surface of the sample, and the movement in it is measured using simultaneously transmitted probing ultrasonic waves. Then scatterers in the sample move sinusoidally under the forced vibration, and the reflected ultrasonic waves are subject to the frequency modulation by the Doppler effect. The amplitude of vibration is estimated from the frequency modulation index of the reflected waves. This is derived from the amplitudes of the spectrum components of the output of the quadrature detector of the received signal. On the other hand, the phase of vibration is estimated from the angle of the fundamental spectrum component. Basic experiments have been carried out using a 3.0-MHz ultrasonic wave system. The accuracy of the method is evaluated and two-dimensional color maps of the amplitude and phase are shown for several phantoms, as well as tissues, in vivo.