Delays in Grip Initiation and Termination in Persons With Stroke: Effects of Arm Support and Active Muscle Stretch Exercise

2009 ◽  
Vol 101 (6) ◽  
pp. 3108-3115 ◽  
Author(s):  
Na Jin Seo ◽  
William Z. Rymer ◽  
Derek G. Kamper
Keyword(s):  
Muscular Activity ◽  
Functional Independence ◽  
Stroke Survivors ◽  
Dominant Hand ◽  
Flexor Muscle ◽  
Active Muscle ◽  
Muscle Stretch ◽  
Arm Support ◽  
Flexor Muscles ◽  
Neurologically Intact

Stroke survivors' difficulty in releasing grasped objects may be attributable not only to impaired finger extension but also to delays in terminating activity in the gripping flexor muscles. This study was undertaken 1) to quantify the time needed to initiate and terminate grip muscular activity following stroke and 2) to examine effects of arm support, grip location, and active muscle stretch on the delays recorded in the paretic hand. Delays in initiation and termination of finger flexor muscle activity in response to an auditory stimulus were measured for both paretic and nonparetic hands of ten stroke survivors with chronic hemiparesis and the dominant hand of five neurologically intact subjects. Additionally, the delays for the paretic hand were recorded while an external arm support was used and after 30 min of active muscle stretch. We found that delays in grip initiation and termination were greatest for the paretic hand (1.9 and 5.0 s), followed by the nonparetic hand (0.5 and 1.6 s), and least for the control hand (0.2 and 0.4 s). Arm support reduced delay in grip termination 37% for the paretic hand. Repeated active muscle stretch resulted in 24% reduced delay in grip initiation and 32% increased delay in grip termination for the paretic hand. Therapies and interventions reducing these delays may improve the ability to grasp and release objects and thus increase functional independence for stroke survivors.

scholarly journals Characterizing differential poststroke corticomotor drive to the dorsi- and plantarflexor muscles during resting and volitional muscle activation

2017 ◽  
Vol 117 (4) ◽  
pp. 1615-1624 ◽  
Author(s):  
Jacqueline A. Palmer ◽  
Ryan Zarzycki ◽  
Susanne M. Morton ◽  
Trisha M. Kesar ◽  
Stuart A. Binder-Macleod
Keyword(s):  
Muscle Contraction ◽  
Muscle Activation ◽  
Foot Drop ◽  
Stroke Survivors ◽  
Active Muscle ◽  
Corticomotor Excitability ◽  
Paretic Limb ◽  
Walking Recovery ◽  
Neurologically Intact ◽  
Plantarflexor Muscles

Imbalance of corticomotor excitability between the paretic and nonparetic limbs has been associated with the extent of upper extremity motor recovery poststroke, is greatly influenced by specific testing conditions such as the presence or absence of volitional muscle activation, and may vary across muscle groups. However, despite its clinical importance, poststroke corticomotor drive to lower extremity muscles has not been thoroughly investigated. Additionally, whereas conventional gait rehabilitation strategies for stroke survivors focus on paretic limb foot drop and dorsiflexion impairments, most contemporary literature has indicated that paretic limb propulsion and plantarflexion impairments are the most significant limiters to poststroke walking function. The purpose of this study was to compare corticomotor excitability of the dorsi- and plantarflexor muscles during resting and active conditions in individuals with good and poor poststroke walking recovery and in neurologically intact controls. We found that plantarflexor muscles showed reduced corticomotor symmetry between paretic and nonparetic limbs compared with dorsiflexor muscles in individuals with poor poststroke walking recovery during active muscle contraction but not during rest. Reduced plantarflexor corticomotor symmetry during active muscle contraction was a result of reduced corticomotor drive to the paretic muscles and enhanced corticomotor drive to the nonparetic muscles compared with the neurologically intact controls. These results demonstrate that atypical corticomotor drive exists in both the paretic and nonparetic lower limbs and implicate greater severity of corticomotor impairments to plantarflexor vs. dorsiflexor muscles during muscle activation in stroke survivors with poor walking recovery. NEW & NOTEWORTHY The present study observed that lower-limb corticomotor asymmetry resulted from both reduced paretic and enhanced nonparetic limb corticomotor excitability compared with neurologically intact controls. The most asymmetrical corticomotor drive was observed in the plantarflexor muscles of individuals with poor poststroke walking recovery. This suggests that neural function of dorsi- and plantarflexor muscles in both paretic and nonparetic limbs may play a role in poststroke walking function, which may have important implications when developing targeted poststroke rehabilitation programs to improve walking ability.

scholarly journals Finger-thumb coupling contributes to exaggerated thumb flexion in stroke survivors

2014 ◽  
Vol 111 (12) ◽  
pp. 2665-2674 ◽  
Author(s):  
Derek G. Kamper ◽  
Heidi C. Fischer ◽  
Megan O. Conrad ◽  
Joseph D. Towles ◽  
William Z. Rymer ◽  
...  
Keyword(s):  
Voluntary Activation ◽  
Strong Interactions ◽  
Stroke Survivors ◽  
Rehabilitation Outcomes ◽  
Flexor Muscles ◽  
Hand Impairment ◽  
Passive Stretch ◽  
Electromyographic Signals ◽  
Neurologically Intact ◽  
Finger Flexor Muscles

The purpose of this study was to investigate altered finger-thumb coupling in individuals with chronic hemiparesis poststroke. First, an external device stretched finger flexor muscles by passively rotating the metacarpophalangeal (MCP) joints. Subjects then performed isometric finger or thumb force generation. Forces/torques and electromyographic signals were recorded for both the thumb and finger muscles. Stroke survivors with moderate ( n = 9) and severe ( n = 9) chronic hand impairment participated, along with neurologically intact individuals ( n = 9). Stroke survivors exhibited strong interactions between finger and thumb flexors. The stretch reflex evoked by stretch of the finger flexors of stroke survivors led to heteronymous reflex activity in the thumb, while attempts to produce isolated voluntary finger MCP flexion torque/thumb flexion force led to increased and undesired thumb force/finger MCP torque production poststroke with a striking asymmetry between voluntary flexion and extension. Coherence between the long finger and thumb flexors estimated using intermuscular electromyographic correlations, however, was small. Coactivation of thumb and finger flexor muscles was common in stroke survivors, whether activation was evoked by passive stretch or voluntary activation. The coupling appears to arise from subcortical or spinal sources. Flexor coupling between the thumb and fingers seems to contribute to undesired thumb flexor activity after stroke and may impact rehabilitation outcomes.

Isokinetic Strength After ACL Reconstruction: Influence of Concomitant Anterolateral Ligament Reconstruction

2021 ◽  
pp. 194173812110054
Author(s):  
Benoit Gillet ◽  
Yoann Blache ◽  
Isabelle Rogowski ◽  
Grégory Vigne ◽  
Bertrand Sonnery-Cottet ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Ligament Reconstruction ◽  
Knee Extensor ◽  
Anterolateral Ligament ◽  
Flexor Muscle ◽  
Knee Flexor ◽  
Strength Recovery ◽  
Flexor Muscles ◽  
Knee Muscle ◽  
Knee Muscle Strength

Background: To reduce the rate of anterior cruciate ligament (ACL) graft rupture, recent surgeries have involved anterolateral ligament reconstruction (ALLR). This reconstruction procedure harvests more knee flexor muscle tendons than isolated ACL reconstruction (ACLR), but its influence on knee muscle strength recovery remains unknown. This study aimed to assess the influence of ALLR with a gracilis graft on the strength of the knee extensor and flexor muscles at 6 months postoperatively. Hypothesis: The additional amount of knee flexor harvest for ALLR would result in impairment in knee flexor muscle strength at 6 months postoperatively. Study Design: Retrospective cohort study. Level of Evidence: Level 2. Methods: A total of 186 patients were assigned to 2 groups according to the type of surgery: ACL + ALLR (graft: semitendinosus + gracilis, n = 119) or isolated ACLR (graft: semitendinosus, n = 67). The strength of the knee extensor and flexor muscles was assessed using an isokinetic dynamometer at 90, 180, and 240 deg/s for concentric and 30 deg/s for eccentric contractions and compared between groups using analysis of variance statistical parametric mapping. Results: Regardless of the surgery and the muscle, the injured leg produced significantly less strength than the uninjured leg throughout knee flexion and extension from 30° to 90° for each angular velocity (30, 90, 180, and 240 deg/s). However, the knee muscle strength was similar between the ACL + ALLR and ACLR groups. Conclusion: The addition of ALLR using the gracilis tendon during ACLR does not alter the muscle recovery observed at 6 months postoperatively. Clinical Relevance: Although more knee flexor muscle tendons were harvested in ACL + ALLR, the postoperative strength recovery was similar to that of isolated ACLR.

Ergonomics in the Dental Clinic

2000 ◽  
Vol 44 (26) ◽  
pp. 197-200
Author(s):  
Rose-Ange Proteau
Keyword(s):  
Return To Work ◽  
Muscular Activity ◽  
Pectoral Girdle ◽  
Dental Hygienists ◽  
Dental Clinic ◽  
Arm Support ◽  
Muscular Effort

A number of dental hygienists have developed pathologies that cause them to be absent from work for long periods of time, and making it difficult for them to return to work. Hygienists' work involves extended static muscular effort in the neck and pectoral girdle, combined with recurrent dynamic movements of the wrist and fingers, associated with efforts to remove tartar from the teeth. Over the last two years, a dozen dental hygienists have consulted us for various shoulder, elbow, wrist, hand and finger problems. Changes in methods, instruments, equipment and the environment have allowed hygienists to adopt safer working positions. Reduced muscular activity was confirmed by EMG testing. The use of telescopic pivoting armrests has facilitated the adoption of new working methods by dental hygienists, and also provided needed arm support. A new concept for a pivoting armrest has been developed with round gel elbows-rests.

scholarly journals Hindlimb muscular activity, kinetics and kinematics of cats jumping to their maximum achievable heights

1981 ◽  
Vol 91 (1) ◽  
pp. 73-86 ◽  
Author(s):  
F. E. Zajac ◽  
M. R. Zomlefer ◽  
W. S. Levine
Keyword(s):  
Vertical Jump ◽  
Muscular Activity ◽  
Dynamic State ◽  
Extensor Muscles ◽  
Ankle Joints ◽  
Flexor Muscles ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces ◽  
Propulsion Phase

Cats were trained to jump from a force platform to their maximum achievable heights. Vertical ground reaction forces developed by individual hindlimbs showed that the propulsion phase consists of two epochs. During the initial “preparatory phase' the cat can traverse many different paths. Irrespective of the path traversed, however, the cat always attains the same position, velocity and momentum at the end of this phase. Starting from this dynamic state the cat during the subsequent “launching phase' (about 150 ms long) generates significant propulsion as its hindlimbs develop force with identical, stereotypic profiles. Cinematographic data, electromyographic data, and computed torques about the hip, knee and ankle joints indicate that during the jump proximal extensor musculature is activated before distal musculature. During terminal experiments when the hindlimb was set at positions corresponding to those in the jump, isometric torques produced by tetanic stimulation of groups of extensor and flexor muscles were compared with computed torques developed by the same cat during previous jumps. These comparisons suggest that extensor muscles of the hindlimb are fully activated during the maximal vertical jump.

scholarly journals A Comparative Study of Conventional Physiotherapy versus Robot-Assisted Gait Training Associated to Physiotherapy in Individuals with Ataxia after Stroke

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Marcia Belas dos Santos ◽  
Clarissa Barros de Oliveira ◽  
Arly dos Santos ◽  
Cristhiane Garabello Pires ◽  
Viviana Dylewski ◽  
...  
Keyword(s):  
Activities Of Daily Living ◽  
Daily Living ◽  
Controlled Trial ◽  
Gait Training ◽  
Functional Independence ◽  
Chronic Stroke ◽  
Wilcoxon Test ◽  
Stroke Survivors ◽  
Registration Number ◽  
One Year

Objectives. To assess the influence of RAGT on balance, coordination, and functional independence in activities of daily living of chronic stroke survivors with ataxia at least one year of injury.Methods. It was a randomized controlled trial.The patients were allocated to either therapist-assisted gait training (TAGT) or robotic-assisted gait training (RAGT). Both groups received 3 weekly sessions of physiotherapy with an estimated duration of 60 minutes each and prescribed home exercises. The following outcome measures were evaluated prior to and after the completion of the 5-month protocol treatment: BBS, TUG test, FIM, and SARA. For intragroup comparisons, the Wilcoxon test was used, and the Mann–Whitney test was used for between-group comparison.Results. Nineteen stroke survivors with ataxia sequel after one year of injury were recruited. Both groups showed statistically significant improvement (P<0.05) in balance, functional independencein, and general ataxia symptoms. There were no statistically significant differences (P<0.05) for between-group comparisons both at baseline and after completion of the protocol.Conclusions. Chronic stroke patients with ataxia had significant improvements in balance and independence in activities of daily living after RAGT along with conventional therapy and home exercises. This trial was registered with trial registration number39862414.6.0000.5505.

Modulatory effects of nitric oxide on synaptic depression in the crayfish neuromuscular system

2000 ◽  
Vol 203 (23) ◽  
pp. 3595-3602 ◽  
Author(s):  
H. Aonuma ◽  
T. Nagayama ◽  
M. Takahata
Keyword(s):  
Nitric Oxide ◽  
Neuromuscular Transmission ◽  
Procambarus Clarkii ◽  
Synaptic Depression ◽  
Physiological Property ◽  
Muscle Fibres ◽  
Flexor Muscle ◽  
Bath Application ◽  
Flexor Muscles ◽  
Stimulation Of

A characteristic physiological property of the neuromuscular junction between giant motor neurones (MoGs) and fast flexor muscles in crayfish is synaptic depression, in which repetitive electrical stimulation of the MoG results in a progressive decrease in excitatory junction potential (EJP) amplitude in flexor muscle fibres. Previous studies have demonstrated that l-arginine (l-Arg) modulates neuromuscular transmission. Since l-Arg is a precursor of nitric oxide (NO), we examined the possibility that NO may be involved in modulating neuromuscular transmission from MoGs to abdominal fast flexor muscles. The effect of a NO-generating compound, NOC7, was similar to that of l-Arg, reversibly decreasing the EJP amplitude mediated by the MoG. While NOC7 reduced the amplitude of the EJP, it induced no significant change in synaptic depression. In contrast, a scavenger of free radical NO, carboxy-PTIO, and an inhibitor of nitric oxide synthase, l-NAME, reversibly increased the EJP amplitude mediated by MoGs. Synaptic depression mediated by repetitive stimulation of MoGs at 1 Hz was partially blocked by bath application of l-NAME. Bath application of a NO scavenger, a NOS inhibitor and NO-generating compounds had no significant effects on the depolarisation of the muscle fibres evoked by local application of l-glutamate. The opposing effects on EJP amplitude of NOC7 and of carboxy-PTIO and l-NAME suggest that endogenous NO presynaptically modulates neuromuscular transmission and that it could play a prominent role at nerve terminals in eliciting MoG-mediated synaptic depression in the crayfish Procambarus clarkii.

scholarly journals Influence of Ball Impact Location on Racquet Kinematics, Forearm Muscle Activation and Shot Accuracy during the Forehand Groundstrokes in Tennis

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 89
Author(s):  
Masahiro Ikenaga ◽  
Nobue Okuma ◽  
Hiroki Nishiyama ◽  
Shinichiro Chiba ◽  
Katsutoshi Nishino ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Muscular Activity ◽  
Side Impact ◽  
Ball Impact ◽  
Tennis Players ◽  
Impact Location ◽  
Flexor Muscles ◽  
Flight Parameters ◽  
Extensor Carpi Radialis ◽  
Forearm Muscle

We aimed to clarify the effect of ball–racquet impact locations on the dynamic behavior of tennis racquet, the accuracy of shots and muscle activation of the forearm. Eight male intermediate tennis players performed ten forehand groundstrokes. A motion capture system was used to measure the motions of racquet, ball and human body at 2000 Hz, and electromyography (EMG) activities of wrist extensor and flexor muscles were measured simultaneously. The flight parameters of the ball were measured by ballistic measurement equipment. All shots were divided into tertiles based on ball impact location along the lateral axis of tennis racquet. We found that the off-center, upper-side impact induces a larger muscular activity in extensor carpi radialis. Passive radial deviation of the wrist occurring immediately after ball impact may account for this. Furthermore, the off-center, upper-side impact could be associated with a missed shot having a lower, outward ball launch angle.

Ultrastructural characterization of superficial and deep flexor muscles in the crayfish thorax

1981 ◽  
Vol 59 (3) ◽  
pp. 357-363 ◽  
Author(s):  
R. L. Crabtree ◽  
R. G. Sherman
Keyword(s):  
Muscle Fibers ◽  
Longitudinal Axis ◽  
Flexor Muscle ◽  
Ultrastructural Characterization ◽  
Flexor Muscles

Transmission electon microscopy revealed that all of the superficial flexor muscle fibers in the crayfish thorax possess sarcomeres 8–10 μm in length, 12 thin myofilaments around each thick myofilament, no H zone, and irregular Z lines. This characterizes them as tonic. All of the deep flexor fibers possess sarcomeres 2–4 μm in length, six myofilaments around each thick myofilament, a distinct H zone, and Z lines that are perpendicular to the longitudinal axis of the fiber. This characterizes them as phasic. Differences in the distribution of mitochondria and glycogen granules and in the organization of synaptic regions also are noted.

Sign in / Sign up

Export Citation Format

Share Document