Changes in wrist muscle activity with forearm posture: implications for the study of sensorimotor transformations

2012 ◽  
Vol 108 (11) ◽  
pp. 2884-2895 ◽  
Author(s):  
Aymar de Rugy ◽  
Rahman Davoodi ◽  
Timothy J. Carroll
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Reference Frames ◽  
Wrist Joint ◽  
Isometric Force ◽  
Joint Space ◽  
Coordinate Frame ◽  
Joint Rotation ◽  
Sensorimotor Transformations ◽  
Direction Of Movement

The primate wrist is an ideal model system for studying the reference frames in which movements are coded within the central nervous system, as a simple rotation of the forearm allows dissociation between extrinsic and body-referenced coordinates. Important information regarding coordinate frame transformations has been obtained using this system, particularly from studies involving extracellular cortical and spinal recordings from monkeys. Because preferred directions of muscle use were reported to rotate by less than half of the joint rotation, the system was considered to dissociate three reference frames: extrinsic (direction of movement in space), muscle (activity of muscles), and joint (angle of the wrist joint). However, given the relatively minor changes in reported muscle biomechanics with human forearm rotation, the reported distinction between joint space and muscle space is surprisingly large. Here, we reassessed patterns of wrist muscle activity with changes in forearm posture in humans, during an isometric force-aiming task with a device that enabled stringent control of the musculoskeletal configuration. Results show that the preferred directions for wrist muscle activation closely follow forearm orientation (i.e., by 88%). Control experiments confirmed this, whether the hand was clamped passively by a device or grasped a handle. Furthermore, the remaining 12% discrepancy between intended changes in wrist orientation and muscle use also occurred for muscle-pulling directions obtained by intramuscular electrical stimulation. The findings prompt reconsideration of data based on the previously reported dissociation between joint space and muscle space and have critical implications for future investigations of sensorimotor transformations and their adaptation using the wrist.

In vivo measurement of human wrist extensor muscle sarcomere length changes

1994 ◽  
Vol 71 (3) ◽  
pp. 874-881 ◽  
Author(s):  
R. L. Lieber ◽  
G. J. Loren ◽  
J. Friden
Keyword(s):  
Muscle Activation ◽  
Sarcomere Length ◽  
Wrist Joint ◽  
Full Extension ◽  
Joint Rotation ◽  
In Vivo Measurement ◽  
Tendon Lengthening ◽  
Angle Rotation ◽  
Length Changes

1. Human extensor carpi radialis brevis (ECRB) sarcomere length was measured intraoperatively in five subjects using laser diffraction. 2. In a separate cadaveric study, ECRB tendons were loaded to the muscle's predicted maximum tetanic tension, and tendon strain was measured to estimate active sarcomere shortening at the expense of tendon lengthening. 3. As the wrist joint was passively flexed from full extension to full flexion, ECRB sarcomere length increased from 2.6 to 3.4 microns at a rate of 7.6 nm/deg joint angle rotation. Correcting for tendon elongation during muscle activation yielded an active sarcomere length range of 2.44 to 3.33 microns. Maximal predicted sarcomere shortening accompanying muscle activation was dependent on initial sarcomere length and was always < 0.15 microns, suggesting a minimal effect of tendon compliance. 4. Thin filament lengths measured from electron micrographs of muscle biopsies obtained from the same region of the ECRB muscles were 1.30 +/- .027 (SE) microns whereas thick filaments were 1.66 +/- .027 microns long, suggesting an optimal sarcomere length of 2.80 microns and a maximum sarcomere length for active force generation of 4.26 microns. 5. These experiments demonstrate that human skeletal muscles can function on the descending limb of their sarcomere length-tension relationship under physiological conditions. Thus, muscle force changes during joint rotation are an important component of the motor control system.

scholarly journals A Systematic Review of EMG Applications for the Characterization of Forearm and Hand Muscle Activity during Activities of Daily Living: Results, Challenges, and Open Issues

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3035
Author(s):  
Néstor J. Jarque-Bou ◽  
Joaquín L. Sancho-Bru ◽  
Margarita Vergara
Keyword(s):  
Activities Of Daily Living ◽  
Musculoskeletal System ◽  
Muscle Activity ◽  
Daily Living ◽  
Muscle Activation ◽  
Human Hand ◽  
Hand Motion ◽  
Biomechanical Models ◽  
Rehabilitation Protocols ◽  
Open Issues

The role of the hand is crucial for the performance of activities of daily living, thereby ensuring a full and autonomous life. Its motion is controlled by a complex musculoskeletal system of approximately 38 muscles. Therefore, measuring and interpreting the muscle activation signals that drive hand motion is of great importance in many scientific domains, such as neuroscience, rehabilitation, physiotherapy, robotics, prosthetics, and biomechanics. Electromyography (EMG) can be used to carry out the neuromuscular characterization, but it is cumbersome because of the complexity of the musculoskeletal system of the forearm and hand. This paper reviews the main studies in which EMG has been applied to characterize the muscle activity of the forearm and hand during activities of daily living, with special attention to muscle synergies, which are thought to be used by the nervous system to simplify the control of the numerous muscles by actuating them in task-relevant subgroups. The state of the art of the current results are presented, which may help to guide and foster progress in many scientific domains. Furthermore, the most important challenges and open issues are identified in order to achieve a better understanding of human hand behavior, improve rehabilitation protocols, more intuitive control of prostheses, and more realistic biomechanical models.

scholarly journals Is the Occurrence of the Sticking Region in Maximum Smith Machine Squats the Result of Diminishing Potentiation and Co-Contraction of the Prime Movers among Recreationally Resistance Trained Males?

2021 ◽  
Vol 18 (3) ◽  
pp. 1366
Author(s):  
Roland van den Tillaar ◽  
Eirik Lindset Kristiansen ◽  
Stian Larsen
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Gluteus Maximus ◽  
Knee Extensors ◽  
Force Output ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Prime Movers ◽  
Almost All ◽  
Height Data

This study compared the kinetics, barbell, and joint kinematics and muscle activation patterns between a one-repetition maximum (1-RM) Smith machine squat and isometric squats performed at 10 different heights from the lowest barbell height. The aim was to investigate if force output is lowest in the sticking region, indicating that this is a poor biomechanical region. Twelve resistance trained males (age: 22 ± 5 years, mass: 83.5 ± 39 kg, height: 1.81 ± 0.20 m) were tested. A repeated two-way analysis of variance showed that Force output decreased in the sticking region for the 1-RM trial, while for the isometric trials, force output was lowest between 0–15 cm from the lowest barbell height, data that support the sticking region is a poor biomechanical region. Almost all muscles showed higher activity at 1-RM compared with isometric attempts (p < 0.05). The quadriceps activity decreased, and the gluteus maximus and shank muscle activity increased with increasing height (p ≤ 0.024). Moreover, the vastus muscles decreased only for the 1-RM trial while remaining stable at the same positions in the isometric trials (p = 0.04), indicating that potentiation occurs. Our findings suggest that a co-contraction between the hip and knee extensors, together with potentiation from the vastus muscles during ascent, creates a poor biomechanical region for force output, and thereby the sticking region among recreationally resistance trained males during 1-RM Smith machine squats.

scholarly journals Ankle Muscle Activations during Different Foot-Strike Patterns in Running

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3422
Author(s):  
Jian-Zhi Lin ◽  
Wen-Yu Chiu ◽  
Wei-Hsun Tai ◽  
Yu-Xiang Hong ◽  
Chung-Yu Chen
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Stance Phase ◽  
Inertial Sensors ◽  
Plantar Flexion ◽  
Intraclass Correlation ◽  
Biceps Femoris ◽  
Ankle Muscle ◽  
Foot Strike ◽  
Muscle Activations

This study analysed the landing performance and muscle activity of athletes in forefoot strike (FFS) and rearfoot strike (RFS) patterns. Ten male college participants were asked to perform two foot strikes patterns, each at a running speed of 6 km/h. Three inertial sensors and five EMG sensors as well as one 24 G accelerometer were synchronised to acquire joint kinematics parameters as well as muscle activation, respectively. In both the FFS and RFS patterns, according to the intraclass correlation coefficient, excellent reliability was found for landing performance and muscle activation. Paired t tests indicated significantly higher ankle plantar flexion in the FFS pattern. Moreover, biceps femoris (BF) and gastrocnemius medialis (GM) activation increased in the pre-stance phase of the FFS compared with that of RFS. The FFS pattern had significantly decreased tibialis anterior (TA) muscle activity compared with the RFS pattern during the pre-stance phase. The results demonstrated that the ankle strategy focused on controlling the foot strike pattern. The influence of the FFS pattern on muscle activity likely indicates that an athlete can increase both BF and GM muscles activity. Altered landing strategy in cases of FFS pattern may contribute both to the running efficiency and muscle activation of the lower extremity. Therefore, neuromuscular training and education are required to enable activation in dynamic running tasks.

scholarly journals The Effects of Core Stabilization Exercise with the Abdominal Drawing-in Maneuver Technique versus General Strengthening Exercise on Lumbar Segmental Motion in Patients with Clinical Lumbar Instability: A Randomized Controlled Trial with 12-Month Follow-Up

2021 ◽  
Vol 18 (15) ◽  
pp. 7811
Author(s):  
Rungthip Puntumetakul ◽  
Pongsatorn Saiklang ◽  
Weerasak Tapanya ◽  
Thiwaphon Chatprem ◽  
Jaturat Kanpittaya ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Controlled Trial ◽  
Abdominal Muscle ◽  
Segmental Motion ◽  
Lumbar Instability ◽  
Stabilization Exercise ◽  
Core Stabilization ◽  
Core Stabilization Exercise

Trunk stability exercises that focus on either deep or superficial muscles might produce different effects on lumbar segmental motion. This study compared outcomes in 34 lumbar instability patients in two exercises at 10 weeks and 12 months follow up. Participants were divided into either Core stabilization (deep) exercise, incorporating abdominal drawing-in maneuver technique (CSE with ADIM), or General strengthening (superficial) exercise (STE). Outcome measures were pain, muscle activation, and lumbar segmental motion. Participants in CSE with ADIM had significantly less pain than those in STE at 10 weeks. They showed significantly more improvement of abdominal muscle activity ratio than participants in STE at 10 weeks and 12 months follow-up. Participants in CSE with ADIM had significantly reduced sagittal translation at L4-L5 and L5-S1 compared with STE at 10 weeks. Participants in CSE with ADIM had significantly reduced sagittal translations at L4-L5 and L5-S1 compared with participants in STE at 10 weeks, whereas STE demonstrated significantly increased sagittal rotation at L4-L5. However, at 12 months follow-up, levels of lumbar sagittal translation were increased in both groups. CSE with ADIM which focuses on increasing deep trunk muscle activity can reduce lumbar segmental translation and should be recommended for lumbar instability.

scholarly journals Biomechanical analysis of an unpowered hip flexion orthosis on individuals with and without multiple sclerosis

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Ross M. Neuman ◽  
Staci M. Shearin ◽  
Karen J. McCain ◽  
Nicholas P. Fey
Keyword(s):  
Multiple Sclerosis ◽  
Muscle Activity ◽  
Healthy Subjects ◽  
Muscle Activation ◽  
Assistive Technologies ◽  
Lower Limbs ◽  
Biomechanical Analysis ◽  
Foot Drop ◽  
Plantar Flexors ◽  
Hip Flexion

Abstract Background Gait impairment is a common complication of multiple sclerosis (MS). Gait limitations such as limited hip flexion, foot drop, and knee hyperextension often require external devices like crutches, canes, and orthoses. The effects of mobility-assistive technologies (MATs) prescribed to people with MS are not well understood, and current devices do not cater to the specific needs of these individuals. To address this, a passive unilateral hip flexion-assisting orthosis (HFO) was developed that uses resistance bands spanning the hip joint to redirect energy in the gait cycle. The purpose of this study was to investigate the short-term effects of the HFO on gait mechanics and muscle activation for people with and without MS. We hypothesized that (1) hip flexion would increase in the limb wearing the device, and (2) that muscle activity would increase in hip extensors, and decrease in hip flexors and plantar flexors. Methods Five healthy subjects and five subjects with MS walked for minute-long sessions with the device using three different levels of band stiffness. We analyzed peak hip flexion and extension angles, lower limb joint work, and muscle activity in eight muscles on the lower limbs and trunk. Single-subjects analysis was used due to inter-subject variability. Results For subjects with MS, the HFO caused an increase in peak hip flexion angle and a decrease in peak hip extension angle, confirming our first hypothesis. Healthy subjects showed less pronounced kinematic changes when using the device. Power generated at the hip was increased in most subjects while using the HFO. The second hypothesis was not confirmed, as muscle activity showed inconsistent results, however several subjects demonstrated increased hip extensor and trunk muscle activity with the HFO. Conclusions This exploratory study showed that the HFO was well-tolerated by healthy subjects and subjects with MS, and that it promoted more normative kinematics at the hip for those with MS. Future studies with longer exposure to the HFO and personalized assistance parameters are needed to understand the efficacy of the HFO for mobility assistance and rehabilitation for people with MS.

scholarly journals Role of Occupational Footwear and Prolonged Walking on Lower Extremity Muscle Activation during Maximal Exertions and Postural Stability Tasks

Biomechanics ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 202-213
Author(s):  
Harish Chander ◽  
Sachini N. K. Kodithuwakku Arachchige ◽  
Alana J. Turner ◽  
Reuben F. Burch V ◽  
Adam C. Knight ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Muscle Activity ◽  
Repeated Measures ◽  
Postural Stability ◽  
Muscle Activation ◽  
Medial Gastrocnemius ◽  
Lower Extremity Muscle ◽  
Prolonged Duration ◽  
The Mean ◽  
The Impact

Background: Occupational footwear and a prolonged duration of walking have been previously reported to play a role in maintaining postural stability. The purpose of this paper was to analyze the impact of three types of occupational footwear: the steel-toed work boot (ST), the tactical work boot (TB), and the low-top work shoe (LT) on previously unreported lower extremity muscle activity during postural stability tasks. Methods: Electromyography (EMG) muscle activity was measured from four lower extremity muscles (vastus medialis (VM), medial hamstrings (MH), tibialis anterior (TA), and medial gastrocnemius (MG) during maximal voluntary isometric contractions (MVIC) and during a sensory organization test (SOT) every 30 min over a 4 h simulated workload while wearing ST, TB, and LT footwear. The mean MVIC and the mean and percentage MVIC during each SOT condition from each muscle was analyzed individually using a repeated measures ANOVA at an alpha level of 0.05. Results: Significant differences (p < 0.05) were found for maximal exertions, but this was limited to only the time main effect. No significant differences existed for EMG measures during the SOT. Conclusion: The findings suggest that occupational footwear type does not influence lower extremity muscle activity during both MVIC and SOT. Significantly lower muscle activity during maximal exertions over the course of the 4 h workload was evident, which can be attributed to localized muscular fatigue, but this was not sufficient to impact muscle activity during postural stability tasks.

Development of an Apparatus for Bilateral Rhythmical Training of Arm Movement Via Linear and Elliptical Trajectories of Various Directions

2014 ◽  
Vol 8 (3) ◽  
Author(s):  
Zlatko Matjačić ◽  
Matjaž Zadravec ◽  
Jakob Oblak
Keyword(s):  
Muscle Activation ◽  
Arm Movement ◽  
Emg Activity ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Arm Cycling ◽  
Arm Reaching ◽  
Direction Of Movement ◽  
Muscle Groups ◽  
Neurologically Intact

Clinical rehabilitation of individuals with various neurological disorders requires a significant number of movement repetitions in order to improve coordination and restoration of appropriate muscle activation patterns. Arm reaching movement is frequently practiced via motorized arm cycling ergometers where the trajectory of movement is circular thus providing means for practicing a single and rather nonfunctional set of muscle activation patterns, which is a significant limitation. We have developed a novel mechanism that in the combination with an existing arm ergometer device enables nine different movement modalities/trajectories ranging from purely circular trajectory to four elliptical and four linear trajectories where the direction of movement may be varied. The main objective of this study was to test a hypothesis stating that different movement modalities facilitate differences in muscle activation patterns as a result of varying shape and direction of movement. Muscle activation patterns in all movement modalities were assessed in a group of neurologically intact individuals in the form of recording the electromyographic (EMG) activity of four selected muscle groups of the shoulder and the elbow. Statistical analysis of the root mean square (RMS) values of resulting EMG signals have shown that muscle activation patterns corresponding to each of the nine movement modalities significantly differ in order to accommodate to variation of the trajectories shape and direction. Further, we assessed muscle activation patterns following the same protocol in a selected clinical case of hemiparesis. These results have shown the ability of the selected case subject to produce different muscle activation patterns as a response to different movement modalities which show some resemblance to those assessed in the group of neurologically intact individuals. The results of the study indicate that the developed device may significantly extend the scope of strength and coordination training in stroke rehabilitation which is in current clinical rehabilitation practice done through arm cycling.

scholarly journals Alteration in HDEMG Spatial Parameters of Trunk Muscle Due to Handle Design during Pushing

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6646
Author(s):  
Jacqueline Toner ◽  
Jeremy Rickards ◽  
Kenneth Seaman ◽  
Usha Kuruganti
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Trunk Muscle ◽  
Erector Spinae ◽  
Low Back ◽  
Horizontal Orientation ◽  
Low Back Injuries ◽  
Spatial Parameters ◽  
Left And Right ◽  
Pushing And Pulling

Previous research identifies that pushing and pulling is responsible for approximately 9–18% of all low back injuries. Additionally, the handle design of a cart being pushed can dramatically alter a worker’s capacity to push (≅9.5%). Surprisingly little research has examined muscle activation of the low back and its role in muscle function. Therefore, the purpose of this study was to examine the effects of handle design combination of pushing a platform truck cart on trunk muscle activity. Twenty participants (10 males and 10 females, mean age = 24.3 ± 4.3 years) pushed 475 lbs using six different handle combinations involving handle orientation (vertical/horizontal/semi-pronated) and handle height (hip/shoulder). Multichannel high-density EMG (HDsEMG) was recorded for left and right rectus abdominis, erector spinae, and external obliques. Pushing at hip height with a horizontal handle orientation design (HH) resulted in significantly less (p < 0.05) muscle activity compared to the majority of other handle designs, as well as a significantly higher entropy than the shoulder handle height involving either the semi-pronated (p = 0.023) or vertical handle orientation (p = 0.028). The current research suggests that the combination of a hip height and horizontal orientation handle design may require increased muscle demand of the trunk and alter the overall muscle heterogeneity and pattern of the muscle activity.

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