Strength and endurance of knee extensors in subjects after paralytic poliomyelitis.

PURPOSE: To compare the strength and endurance of knee extensors in subjects after paralytic poliomyelitis as well as to extend the comparison to healthy subjects. METHOD: Twenty subjects after poliomyelitis with new symptoms (SYM group), 10 without new symptoms (ASYM group) and 15 healthy controls were included. To determine strength, isometric maximal voluntary contraction (MVC) torque of knee extensors in both legs was determined by Biodex dynamometer at 60 degrees knee angle. To determine endurance, the subjects were asked to maintain force in the knee extensors in the same position, in the range between 40-45% of MVC torque, as long as possible. The 'tensiomyography' method was applied to measure the radial displacement of m. rectus femoris during submaximal continuous electrical stimulation until recording a flat response. RESULTS: No significant difference in MVC torque and endurance was found between SYM and ASYM group, as well between the duration of m. rectus femoris response of both groups to submaximal electrical stimulation. MVC torque and endurance of knee extensors with 'normal' strength was significantly lower in post-polio subjects compared to healthy controls. CONCLUSION: Endurance of knee extensor muscles in post-polio subjects is generally and significantly lower than that of knee extensors in healthy subjects, regardless of the implication of normal strength and subjective observations of post-polio subjects.

Web-based surgical educational tools.

This paper describes work being undertaken as part of the WebSET (Web-based Standard Educational Tools) project. The project is producing a standardised suite of interactive three-dimensional educational tools, delivered across the WWW. The major focus will be the use of open technology and standards, and the production of learning components that can be used as building blocks for further development in a wide range of application areas. Two learning disciplines have been selected for the development of the WebSET tools: surgical training, and physiological education. A high quality consortium from across Europe has been assembled with complementary skills in the technologies needed by the project. The project is partly funded by the European Commission.

Measuring of skeletal muscles' dynamic properties.

Many studies have been completed to determine how muscles work. One of the aspects to study is the muscle response and how to measure it. The main aim of this study was to build a noninvasive measuring system that would be simple to use and would measure the muscle response as close to the muscle as possible. The measuring method was based on a magnetic displacement sensor measuring the muscle belly response. The sensor was placed adjacent to the skin over the muscle and measured radial movements of the muscle belly. The muscle response to single twitch electrical stimulation was measured. Different skeletal muscles or muscle groups have different biomechanical characteristics. The rise time of the muscle belly response was the characteristic parameter for this study. The comparison of muscles' responses in terms of the values of their normalized rise time parameters confirmed their identities as slow or fast muscles. The value of the normalized rise time parameter of a slow muscle was four times less than the value of the parameter of a fast muscle. Although the question remains as to how the available measuring techniques provide estimation of skeletal muscles' dynamic properties, this proposed measuring method contributes to a better understanding of skeletal muscles' dynamic properties. It offers a possible way of studying the muscle structure from the muscle's response to electrical stimulation in a simple noninvasive way.

Arm cycloergometry and kinetics of oxygen consumption in paraplegics.

A report is given on studies to determine the best methodological approach in exercise testing of paraplegics. Arm cyclometry was found to be very suitable for wheelchair users with normal upper limbs. Oxygen consumption during exercise was studied and analysed by computer.

Properties of musculus gluteus maximus in above-knee amputees.

The present study aimed at evaluating possible changes of the gluteus maximus muscle bulk size and in the contracting properties of gluteus maximus in the amputated above-knee limb. Seven male above-knee amputees, with a mean age of 47.4 years volunteered to participate in the present study. Twenty-one healthy subjects with a mean age of 34.0 years served as the control group. Muscle belly displacement was measured by means of a precision electromagnetic sensor dc-dc displacement transducer while performing maximal voluntary isometric contractions. The muscle twitch contraction has been quantified by the latency period (T1), time to peak tension (T2) and the slope of the record. A statistically significant decrease in muscle belly displacement on the amputated side has been observed in comparison with controls and non-amputated side. The latency period on the amputated side was significantly longer and the slope less steep than in the control group. These results indicated atrophied and slower gluteus maximus on the amputated side of above-knee amputees.

Effects of electrical stimulation on muscles of children with Duchenne and Becker muscular dystrophy.

Twelve children with progressive muscular dystrophy (10 Duchenne and 2 Becker type) were included in a low-frequency electrical stimulation (LFES) program of the right tibialis anterior (TA) muscle for three months. Muscle strength was estimated by measuring torques in the ankle during short attempts of maximal voluntary isometric contraction (MVIC) in the direction of dorsal flexion of the foot. Muscle fatigue was assessed by the decrease of force during sustained (1-minute) voluntary contraction. The measurements were carried out before the beginning of the stimulation program and immediately after its conclusion. At the end of the stimulation program there were higher torques in 10 out of 12 children in the stimulated leg. The increase in torques in the stimulated leg was statistically significant (p < 0.01). Regarding the fatigue of the stimulated muscle there was no change after the conclusion of stimulation.

Improved motor response due to chronic electrical stimulation of denervated tibialis anterior muscle in humans.

Nine patients with complete denervation of the tibialis anterior were admitted to a stimulation program in order to restore dorsiflexion of the foot. Best results were obtained with pulses of 20-msec pulse width and 20-msec interval. After 3 weeks of training for 2 X 20 min/day, dorsiflexion due to stimulation was increased in all patients. In some of them, gait could be improved during the swing phase using electrical stimulation. The applied training program thus reversed the course of disuse atrophy and proved the feasibility of functional electrical stimulation for patients with denervated muscles.

Improvement of some abnormal motor functions by electrical stimulation.

Clinical results obtained from electrical stimulation of muscle, nerve, spinal cord, cerebellum, and cerebrum are surveyed. Some more data are presented from our own experience with stimulating denervated muscle and cerebellum. Mechanisms which might be responsible for its clinical effects on the muscle, synapse, or nervous system are discussed.

Standardization of kinematic gait measurements and automatic pathological gait pattern diagnostics.

The estimation of patients gait in the field of rehabilitation is the starting point for an appropirate therapy decision and convenient prosthesis or orthosis choice. The measurement and estimation of human locomotion is increasingly being transferred to every day clinical use. In recent times many systems are intended for kinematic gait parameters measurements: stroboscopic photography, movie camera, TV picture analysis, TV signal analysis, chronocyclographical measurement, polarised light goniometer, the "Selspot" system, parallelgram goniometers, exoskeleton goniometers. In the paper the role of the computer in gait measurements is also determined. The problems of the choice of parameters to be measured, unique reference coordinate systems and normal gait pattern are encountered in this work. Finally two versions of pathological gait pattern estimation are described: clinical gait analysis and mathematical quantitative gait analysis. A combination of both methods provides an efficient, compact automatic pathological gait pattern diagnostics.