Kinematics, kinetics and muscle activation patterns of the upper extremity during simulated forward falls

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.

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Electromyographic activation patterns during swallowing in older adults

Scientific Reports ◽

10.1038/s41598-021-84972-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jin Young Ko ◽

Hayoung Kim ◽

Joonyoung Jang ◽

Jun Chang Lee ◽

Ju Seok Ryu

Keyword(s):

Older Adults ◽

Viscous Fluid ◽

Muscle Activation ◽

Fatty Infiltration ◽

Liquid Volume ◽

Type I ◽

Type Ii ◽

Activation Patterns ◽

Muscle Activation Patterns ◽

Age Related

AbstractAge-related weakness due to atrophy and fatty infiltration in oropharyngeal muscles may be related to dysphagia in older adults. However, little is known about changes in the oropharyngeal muscle activation pattern in older adults. This was a prospective and experimental study. Forty healthy participants (20 older [> 60 years] and 20 young [< 60 years] adults) were enrolled. Six channel surface electrodes were placed over the bilateral suprahyoid (SH), bilateral retrohyoid (RH), thyrohyoid (TH), and sternothyroid (StH) muscles. Electromyography signals were then recorded twice for each patient during swallowing of 2 cc of water, 5 cc of water, and 5 cc of a highly viscous fluid. Latency, duration, and peak amplitude were measured. The activation patterns were the same, in the order of SH, TH, and StH, in both groups. The muscle activation patterns were classified as type I and II; the type I pattern was characterized by a monophasic shape, and the type II comprised a pre-reflex phase and a main phase. The oropharyngeal muscles and SH muscles were found to develop a pre-reflex phase specifically with increasing volume and viscosity of the swallowed fluid. Type I showed a different response to the highly viscous fluid in the older group compared to that in the younger group. However, type II showed concordant changes in the groups. Therefore, healthy older people were found to compensate for swallowing with a pre-reflex phase of muscle activation in response to increased liquid volume and viscosity, to adjust for age-related muscle weakness.

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Inter-laboratory comparison of knee biomechanics and muscle activation patterns during gait in patients with knee osteoarthritis

The Knee ◽

10.1016/j.knee.2021.03.001 ◽

2021 ◽

Vol 29 ◽

pp. 500-509

Author(s):

J.C. Schrijvers ◽

D. Rutherford ◽

R. Richards ◽

J.C. van den Noort ◽

M. van der Esch ◽

...

Keyword(s):

Knee Osteoarthritis ◽

Muscle Activation ◽

Knee Biomechanics ◽

Activation Patterns ◽

Muscle Activation Patterns

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Responses in knee joint muscle activation patterns to different perturbations during gait in healthy subjects

Journal of Electromyography and Kinesiology ◽

10.1016/j.jelekin.2021.102572 ◽

2021 ◽

pp. 102572

Author(s):

Jim C. Schrijvers ◽

Josien C. van den Noort ◽

Martin van der Esch ◽

Jaap Harlaar

Keyword(s):

Knee Joint ◽

Healthy Subjects ◽

Muscle Activation ◽

Activation Patterns ◽

Muscle Activation Patterns

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Effects of different initial foot positions on kinematics, muscle activation patterns, and postural control during a sit-to-stand in younger and older adults

Journal of Biomechanics ◽

10.1016/j.jbiomech.2021.110251 ◽

2021 ◽

Vol 117 ◽

pp. 110251

Author(s):

Woohyoung Jeon ◽

Hao-Yuan Hsiao ◽

Lisa Griffin

Keyword(s):

Older Adults ◽

Postural Control ◽

Muscle Activation ◽

Activation Patterns ◽

Muscle Activation Patterns ◽

Sit To Stand

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Functional Gait Recovery after a Combination of Conventional Therapy and Overground Robot-Assisted Gait Training Is Not Associated with Significant Changes in Muscle Activation Pattern: An EMG Preliminary Study on Subjects Subacute Post Stroke

Brain Sciences ◽

10.3390/brainsci11040448 ◽

2021 ◽

Vol 11 (4) ◽

pp. 448

Author(s):

Francesco Infarinato ◽

Paola Romano ◽

Michela Goffredo ◽

Marco Ottaviani ◽

Daniele Galafate ◽

...

Keyword(s):

Conventional Therapy ◽

Muscle Activation ◽

Bilateral Symmetry ◽

Gait Training ◽

Robot Assisted ◽

Activation Patterns ◽

Post Stroke ◽

Muscle Activation Patterns ◽

Preliminary Study ◽

Functional Gait

Background: Overground Robot-Assisted Gait Training (o-RAGT) appears to be a promising stroke rehabilitation in terms of clinical outcomes. The literature on surface ElectroMyoGraphy (sEMG) assessment in o-RAGT is limited. This paper aimed to assess muscle activation patterns with sEMG in subjects subacute post stroke after training with o-RAGT and conventional therapy. Methods: An observational preliminary study was carried out with subjects subacute post stroke who received 15 sessions of o-RAGT (5 sessions/week; 60 min) in combination with conventional therapy. The subjects were assessed with both clinical and instrumental evaluations. Gait kinematics and sEMG data were acquired before (T1) and after (T2) the period of treatment (during ecological gait), and during the first session of o-RAGT (o-RAGT1). An eight-channel wireless sEMG device acquired in sEMG signals. Significant differences in sEMG outcomes were found in the BS of TA between T1 and T2. There were no other significant correlations between the sEMG outcomes and the clinical results between T1 and T2. Conclusions: There were significant functional gains in gait after complex intensive clinical rehabilitation with o-RAGT and conventional therapy. In addition, there was a significant increase in bilateral symmetry of the Tibialis Anterior muscles. At this stage of the signals from the tibialis anterior (TA), gastrocnemius medialis (GM), rectus femoris (RF), and biceps femoris caput longus (BF) muscles of each lower extremity. sEMG data processing extracted the Bilateral Symmetry (BS), the Co-Contraction (CC), and the Root Mean Square (RMS) coefficients. Results: Eight of 22 subjects in the subacute stage post stroke agreed to participate in this sEMG study. This subsample demonstrated a significant improvement in the motricity index of the affected lower limb and functional ambulation. The heterogeneity of the subjects’ characteristics and the small number of subjects was associated with high variability research, functional gait recovery was associated with minimal change in muscle activation patterns.

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