1. The purpose of this study was to evaluate the mechanical response stretch in normal human ankle dorsiflexors at different levels voluntary contraction. In an active muscle, total is sum intrinsic from contractile apparatus, passive tissues, and reflex mediated response. Each these components investigated. 2. incremental stiffness defined as ratio between torque increment amplitude stretch. 14 subjects increased approximately 0.6 N.m/deg 2.5 50% MVC remained constant (+/- 10%) 30 80% MVC....

1 Sensory feedback plays a major role in the regulation of spinal neural locomotor circuitry cats. The present study investigated whether sensory also an important during walking 20 healthy human subjects, by arresting or unloading ankle extensors 6 deg for 210 ms stance phase gait. 2 During walking, significantly (P < 0·05) reduced soleus activity 50 % early and mid-stance at average onset latency 64 ms. 3 amplitude decrease produced were unchanged when common peroneal nerve, which...

The total mechanical response to a stretch in contracting muscle is the sum of from properties fibres prior (intrinsic properties), passive tissues and reflex-mediated contraction fibres. passive, intrinsic 4° ankle extensors both legs nine spastic hemiparetic patients and, as control, left eight healthy subjects were measured. was imposed at top maintained contraction, which varied zero maximal contraction. torque increments, measured 200 ms after stretch, converted into stiffness by...

1. The modulation of the short-latency stretch reflex during walking at different speeds was investigated and compared with standing in healthy human subjects. 2. Ankle joint stretches were applied by a system able to rotate ankle treadmill any phase step cycle. consisted mechanical attached subject's connected motor placed beside means bowden wires. weight total leg subject 900 g. 3. soleus modulated step. In stance phase, amplitude equaled that found matched background electromyogram...

1. The objective of this study was to determine which afferents contribute the medium latency response soleus stretch reflex resulting from an unexpected perturbation during human walking. 2. Fourteen healthy subjects walked on a treadmill at approximately 3.5 km h(-1) with left ankle attached portable stretching device. elicited by applying small amplitude (approximately 8 deg) dorsiflexion perturbations 200 ms after heel contact. 3. Short and responses were observed latencies 55 +/- 5 78 6...

1. During maintained ankle extension with background torques ranging from 0 to 70 N.m, the extensors were stretched by a 5 degree rotation of joint. Maximal stretch velocity was 170 degrees/s. Regression analysis simultaneous measurements total torque and needle surface electromyograms (EMG) soleus gastrocnemius muscles showed that muscle generates about two-thirds maximal (approximately 120 Nm) subjects in sitting position. In addition, it found there is considerable cross talk between when...

One hemiplegic patient with a dropfoot was chronically implanted cuff on the sural nerve, and recordings were made regularly during period of two years. The results showed that human nerve responded in similar way to mechanical inputs applied skin, as tibial did cats (M.K. Haugland, et al., ibid., vol. 2, p. 18-28, 1994), indicating previous experimental systems using natural sensory feedback for closed-loop FNS are possible adapt humans. During walking, recorded signal modulated strongly...

The sensitivity of soleus H-reflexes, T-reflexes, and short-latency stretch reflexes (M1) to presynaptic inhibition evoked by a weak tap applied the biceps femoris tendon or stimulation common peroneal nerve (CPN) was compared in 17 healthy human subjects. H-reflex strongly depressed for period lasting up 300-400 ms (depression 48 +/- 23%, mean SD, control at conditioning test interval 70 ms) tap. In contrast, reflex elicited quick passive dorsiflexion ankle joint not depressed. T-reflex an...

In this study we investigated the effect of human experimental muscle pain on H- and stretch reflexes as indicators changes in spindle sensitivity. Fourteen healthy, male volunteers participated study. Muscle was produced by infusion 5% hypertonic saline over a period 10-15 min m. soleus tibialis anterior. Reflexes were elicited relaxed active (10-15 Nm ankle torque) before, during after pain. Control measurements made with infusions 0.9% isotonic saline. Surface electromyograms (EMG)...

Falls amongst elderly people are often associated with fractures. Training of balance and physical performance can reduce fall risk; however, it remains a challenge to identify individuals at increased risk falling whom this training should be offered. It is believed that assessed by testing performance. In study test battery physiological parameters related falls was designed address in community dwelling population. Ninety-four males females between 70 80 years age were included one year...

Objective: To evaluate a selective implantable drop foot stimulator (ActiGait) in terms of effect on walking and safety.Design: A phase II trial which consecutive sample participants acted as their own controls.Subjects: People who had suffered stroke at least 6 months prior to recruitment drop-foot that affected were recruited from 3 rehabilitation centres Denmark.Methods: Stimulators implanted into all participants.Outcome measures range ankle dorsiflexion with stimulation maximum speed...

When functional neuromuscular stimulation (FNS) is used to restore the use of paralyzed limbs after a spinal cord injury or stroke, it may be possible control using feedback information relayed by natural sensors in skin. In this study authors tested hypothesis that force applied on glabrous skin can extracted from electroneurographic (ENG) signal recorded sensory nerve. They central footpad cat hindlimb as model human fingertip and activity with cuff electrode chronically implanted around...

Recent studies indicate that the hamstrings are essential antagonists in ACL deficient patients. In order to evaluate muscle coordination under physiologic conditions, nine patients with arthroscopically verified total ruptures were compared control volunteers. This comparison was made from electromyograms of thigh muscles and heel contact recordings while walking on a treadmill. While horizontal level, patient's activity did not differ controls, but when knee load increased by uphill,...

The passive tension resulting from dorsiflexion of the ankle was measured in relation to stretching six handball players and soccer players. Corresponding values angle were by a strain gauge potentiometer connected pedal system. versus before 90 minutes after single contract-relax program plantar flexors. Stretching lowered up 18%. Contract-relax performed twice day for 3 weeks flexors 36%. Before last measurements, no 20 hours or more. thus had both short-term effect, matching length...

The objective of this study was to determine if load receptors contribute the afferent-mediated enhancement ankle extensor muscle activity during late stance phase step cycle. Plantar flexion perturbations were presented in while able-bodied human subjects walked on a treadmill that declined by 4%, inclined 4% or held level. plantar perturbation produced transient, but marked, presumably spinally mediated decrease soleus EMG varied directly with inclination. Similarly, magnitude control and...

Aim Clinical determination of spasticity is confounded by the difficulty in distinguishing reflex from passive contributions to muscle stiffness. There is, therefore, a risk that children with cerebral palsy ( CP ) receive antispasticity treatment unnecessarily. To investigate this, we aimed determine contribution mechanisms changes elastic properties muscles and tendons . Method Biomechanical electrophysiological measures were used relative ankle stiffness 35 spastic (21 males, 14 females;...

Stretch of the ankle dorsiflexors was applied at different times walking cycle in 17 human subjects. When stretch swing phase, only small and variable reflex responses were observed active tibialis anterior (TA) muscle. Two that could be distinguished had latencies which comparable with early (M1) late (M3)components three (M1, M2 M3) during tonic dorsiflexion sitting In stance phase a single very large response consistently inactive TA The peak this same latency as M3, but majority subjects...