Functional Problems in Spastic Patients Are Not Caused by Spasticity but by Disordered Motor Control
Anand D. Pandyan, Hermie J. Hermens, Bernard A. Conway in Neurological Rehabilitation, 2018
In healthy human subjects, the monosynaptic Ia afferent pathway thus seems to make only a minor or no contribution to the triceps surae muscle activity in the stance phase of walking. However, with the exaggeration of stretch reflexes in spastic patients it could be expected that they would show some contribution of the pathway to the maintenance of EMG activity, but this does not seem to be the case. In both adults with stroke and children with CP, unloading of the ankle plantarflexors in the stance phase of gait thus produces a depression of soleus EMG activity with a latency similar to that observed in healthy subjects. If anything, this depression is smaller in spastic patients than in healthy subjects (Mazzaro et al. 2007, Willerslev-Olsen et al. 2014), indicating a reduced transmission in the pathway and a reduced contribution of sensory afferent feedback to the activity of the soleus muscle. The clinical significance of this finding is that it is not possible to conclude that sensory input to the spinal cord is exaggerated under functional conditions based on observations of exaggerated reflex responses either at rest or under those functional conditions. It should again be remembered, as pointed out by Sherrington, that reflexes are (fictive) simplified concepts (something that we evoke under very unnatural conditions to serve our diagnostic purposes) that have little relevance to normal physiological integration of sensory feedback.
Lower extremity injuries
Youlian Hong, Roger Bartlett in Routledge Handbook of Biomechanics and Human Movement Science, 2008
Calcaneal tendon pathologies: The calcaneal (Achilles) tendon is formed by confluence of the distal tendons of the gastrocnemius and soleus about 5–6 cm proximal to its insertion site on the posterior aspect of calcaneus. The calcaneal tendon transmits substantial forces developed by the triceps surae muscle group (i.e., gastrocnemius and soleus). For example, Fukashiro et al. (1995) reported peak Achilles tendon force of 2233 N (502 lb) in the squat jump, 1895 N (426 lb) in the countermovement jump, and 3786 N (851 lb) in hopping. Giddings et al. (2000) predicted maximal Achilles tendon force 3.9 BW (body weight) for walking and 7.7 BW for running, with the peak loads at 70 per cent of the stance phase for walking and 60 per cent of stance for running. Pourcelot et al. (2005) found peak tendon forces of about 850N (191 lb) during the stance phase of walking.
Anti-Aging and Regenerative Medicine
Aruna Bakhru in Nutrition and Integrative Medicine, 2018
Caution: Overtraining: In athletes, overtraining occurs when they undergo very high intensity training and take out little time for recovery or regeneration (Fry, Morton, and Keast 1991). There has not been much research on the relationship between the standardized overtraining and impaired recovery (i.e., whether increased in time for recovery occurs due to aging). However, several studies compared recovery patterns following acute exercise between younger and older individuals. Klein et al. (1988) compared a group of physically active young people (19–32 years) and aging persons (64–69 years) to assess the recovery pattern of the triceps surae muscle following muscle fatigue. The study showed that the recovery was slower in older individuals as compared to the young (Klein et al. 1988). But the studies assessing the impact of overtraining on aging included “recreationally active” or sedentary participants, so whether the findings of these studies could be applied to well-trained older individuals is still questionable (Fell and Williams 2008).
Ankle dysfunction in multiple sclerosis and the effects on walking
Published in Disability and Rehabilitation, 2021
Caroline Massot, Marc-Alexandre Guyot, Cécile Donze, Emilie Simoneau, Christophe Gillet, Sébastien Leteneur
Propulsive forces are necessary for propelling the body forward during walking and there are two popular main ideas for explaining the functional role of the ankle during gait: (1) it contributes to propulsive action by pushing on the floor, or (2) it supports and stabilises the body during the stance phase [11]. Although the first hypothesis is commonly found in clinical studies, biomechanical analysis strongly refutes this hypothesis [9,12,13]: during walking, the hip motion is the major contributor to producing propulsive forces by moving the lower-limb forward [14]. Thus, the ankle, through the action of the triceps surae muscle, has a braking action that controls the centre of mass from falling and supports the weight body forward during the stance phase of gait [13]. The objective of this systematic review is to report ankle dysfunction in MS and its effects on walking.
The effectiveness of extracorporeal shock wave therapy to reduce lower limb spasticity in stroke patients: a systematic review and meta-analysis
Published in Topics in Stroke Rehabilitation, 2020
Rosa Cabanas-Valdés, Jordi Calvo-Sanz, Gerard Urrùtia, Pol Serra-Llobet, Albert Pérez-Bellmunt, Ana Germán-Romero
In relation to clinical assessment of spasticity, 10 studies used MAS,43 three studies used Tardieu Scale,44 and others recorded self-reported spasticity by the Visual Analogue Scale (see Table 7). Four studies measured spasticity electrophysiological by H-reflex latency45 and their parameters of Hmax/Mmax ratio (0.5–1 ms). The amplitude of the H-reflex indicates the degree of excitation and inhibition of the spinal cord motor neurons.46 H-reflex latency is usually decreased and Hmax/Mmax ratio is increased47 in patients with spasticity. It was obtained by stimulating the tibial nerve on popliteal fossa eliciting a reflex response in the triceps surae muscle and recording the resulting reflex compound muscle-action potential using an electromyography electrode (see Table 8).
Morphological and functional outcomes of operatively treated Achilles tendon ruptures
Published in The Physician and Sportsmedicine, 2020
Gareth Nicholson, Josh Walker, Zoe Dawson, Athanassios Bissas, Nick Harris
Static ultrasound measurements (Figure 1) of the triceps surae muscle-tendon complex were taken with the participants laying prone on a physiotherapy bench and the ankle joint in a neutral position. Longitudinal images were taken of the muscle belly of m. Gastrocnemius medialis, m. Gastrocnemius lateralis and m. Soleus in both legs using B-mode ultrasound with a 50 mm linear array probe (5 to 12 mHz; Acuson P300, Siemens; Munich). Bilateral transverse plane images of the Achilles tendon for the measurement of the cross-sectional area were taken 40 mm proximal to the calcaneal insertion, while longitudinal images of the Achilles tendon were taken 30, 40 and 50 mm proximal to the calcaneal insertion using a 40 mm linear array probe (6 to 18 mHz). These sites were chosen since the region 20–60 mm proximal to the calcaneal insertion is the most commonly ruptured region [22].
Related Knowledge Centers
- Achilles Tendon
- Femur
- Gastrocnemius Muscle
- Muscle
- Soleus Muscle
- Tibial Nerve
- Calf
- Calcaneus
- Foot
- Knee