scholarly journals Can non-disabled adults reproduce the stiff-knee gait of individuals with stroke?

2020 ◽  
Author(s):  
Odair Bacca ◽  
Melissa Celestino ◽  
José Barela ◽  
Anna Lima ◽  
Ana Barela
Keyword(s):  
Lower Limb ◽  
Knee Flexion ◽  
Muscle Activation ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Gait Pattern ◽  
Activation Level ◽  
Stiff Knee ◽  
Mechanical Constraint ◽  
Disabled Adults

AbstractThis study investigated whether a mechanical constraint of knee flexion in non-disabled individuals could help with reproducing the gait pattern of individuals with stroke. Eleven non-disabled adults (26.6±6.5 years old) and 12 individuals with stroke (52.0±12.8 years old) walked at a self-selected comfortable speed as kinematic and electromyographic data were acquired. Non-disabled adults also walked with an orthosis that limited to 45 degrees of knee flexion. The hip, knee, and ankle joint angles and the muscle activation of the rectus femoris, vastus medialis and lateralis, tibialis anterior, semitendinosus, biceps femoris, and gastrocnemius medialis and lateralis were analyzed. The results demonstrated that non-disabled adults presented similar lower limb excursion to individuals with stroke that affects most joints, although, they displayed a different muscle activation level for most muscles. These results suggest that a mechanical constraint of knee flexion leads to temporal and joint excursion alterations in the lower limb of non-disabled individuals, thereby enabling the reproduction of a gait pattern similar to individuals with stroke. It is also observed that these individuals use different strategies to control muscle activation, which might be related to the lack of control in coordinating muscle activation during gait that is present in individuals with stroke.

scholarly journals Healthy subjects with lax knees use less knee flexion rather than muscle control to limit anterior tibia translation during landing

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Michèle N. J. Keizer ◽  
Juha M. Hijmans ◽  
Alli Gokeler ◽  
Anne Benjaminse ◽  
Egbert Otten
Keyword(s):  
Knee Flexion ◽  
Muscle Activation ◽  
Reaction Force ◽  
Rectus Femoris ◽  
Knee Laxity ◽  
Biceps Femoris ◽  
Level Of Evidence ◽  
Jump Landing ◽  
Muscle Activation Patterns ◽  
Healthy Participants

Abstract Purpose It has been reported that there is no correlation between anterior tibia translation (ATT) in passive and dynamic situations. Passive ATT (ATTp) may be different to dynamic ATT (ATTd) due to muscle activation patterns. This study aimed to investigate whether muscle activation during jumping can control ATT in healthy participants. Methods ATTp of twenty-one healthy participants was measured using a KT-1000 arthrometer. All participants performed single leg hops for distance during which ATTd, knee flexion angles and knee flexion moments were measured using a 3D motion capture system. During both tests, sEMG signals were recorded. Results A negative correlation was found between ATTp and the maximal ATTd (r = − 0.47, p = 0.028). An N-Way ANOVA showed that larger semitendinosus activity was seen when ATTd was larger, while less biceps femoris activity and rectus femoris activity were seen. Moreover, larger knee extension moment, knee flexion angle and ground reaction force in the anterior-posterior direction were seen when ATTd was larger. Conclusion Participants with more ATTp showed smaller ATTd during jump landing. Muscle activation did not contribute to reduce ATTd during impact of a jump-landing at the observed knee angles. However, subjects with large ATTp landed with less knee flexion and consequently showed less ATTd. The results of this study give information on how healthy people control knee laxity during jump-landing. Level of evidence III

Different Muscle-Recruitment Strategies Among Elite Breaststrokers

2015 ◽  
Vol 10 (8) ◽  
pp. 1061-1065 ◽  
Author(s):  
Brice Guignard ◽  
Bjørn H. Olstad ◽  
David Simbaña Escobar ◽  
Jessy Lauer ◽  
Per-Ludvik Kjendlie ◽  
...  
Keyword(s):  
Lower Limb ◽  
Muscle Activation ◽  
Sagittal Plane ◽  
National Level ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Recovery Phase ◽  
Elite Group ◽  
Flexion Extension ◽  
High Level

Purpose:To investigate electromyographical (EMG) profiles characterizing the lower-limb flexion-extension in an aquatic environment in high-level breaststrokers.Methods:The 2-dimensional breaststroke kick of 1 international- and 2 national-level female swimmers was analyzed during 2 maximal 25-m swims. The activities of biceps femoris, rectus femoris, gastrocnemius, and tibialis anterior were recorded.Results:The breaststroke kick was divided in 3 phases, according to the movements performed in the sagittal plane: push phase (PP) covering 27% of the total kick duration, glide phase (GP) 41%, and recovery phase (RP) 32%. Intrasubject reproducibility of the EMG and kinematics was observed from 1 stroke cycle to another. In addition, important intersubject kinematic reproducibility was noted, whereas muscle activities discriminated the subjects: The explosive Pp was characterized by important muscle-activation peaks. During the recovery, muscles were likewise solicited for swimmers 1 (S1) and 2 (S2), while the lowest activities were observed during GP for S2 and swimmer 3 (S3), but not for S1, who maintained major muscle solicitations.Conclusions:The main muscle activities were observed during PP to perform powerful lower-limb extension. The most-skilled swimmer (S1) was the only 1 to solicit her muscles during GP to actively reach better streamlining. Important activation peaks during RP correspond to the limbs acting against water drag. Such differences in EMG strategies among an elite group highlight the importance of considering the muscle parameters used to effectively control the intensity of activation among the phases for a more efficient breaststroke kick.

Effects of Experience on Gymnasts’ Kinematics and Performances

2021 ◽  
Vol 65 (1) ◽  
pp. 1280-1285
Author(s):  
Courtney Middelcoop ◽  
Colten Fales ◽  
Richard T. Stone ◽  
Joseph Kim ◽  
Kristina Schaffhausen ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Maximum Voluntary Contraction ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Voluntary Contraction ◽  
Initial Contact ◽  
Sweet Spot ◽  
Contact Phase ◽  
Consistent Performance ◽  
And Performance

In studying the effects of expertise on different performance aspects of the gymnastic vault event, various springboard types with similar compression forces were evaluated between expert and novice-level gymnasts. Surface EMGs (sEMG) were placed on four major muscles (biceps femoris, rectus femoris, gastrocnemius medialis, and tibialis anterior) to find each gymnasts’ maximum voluntary contraction. Similarly, board compression and knee flexion angles were also captured at various phases of the performed vaults. Given that gymnasts with more expertise were more consistent in their landing spot on the various vault boards, they had more consistent performance outputs as a result. Expert gymnasts did this by more accurately hitting the sweet spot, more consistently activating their hamstring and gastrocnemius, and decreasing variability during the initial contact phase. By doing this, board compression and performance were both optimized. Coaches can use this information to accelerate the development of novice gymnasts by targeting these aspects.

Muscle Activation in the Main Muscle Groups of the Lower Limbs in High-Level Dancesport Athletes

2018 ◽  
Vol 33 (4) ◽  
pp. 231-237
Author(s):  
Encarnación Liébana ◽  
Cristina Monleón ◽  
Raquel Morales ◽  
Carlos Pablos ◽  
Consuelo Moratal ◽  
...  
Keyword(s):  
Tibialis Anterior ◽  
Muscle Activation ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Lower Limbs ◽  
Gastrocnemius Medialis ◽  
Leg Muscles ◽  
Relative Activation ◽  
Muscle Groups ◽  
High Level

Dancers are subjected to high-intensity workouts when they practice dancesport, and according to the literature, they are prone to injury, primarily of the lower limbs. The purpose of this study was to determine whether differences exist in relative activation amplitudes for dancers involved in dancesport due to muscle, gender, and type of dance. Measurements were carried out using surface electromyography equipment during the choreography of a performance in the following leg muscles: rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius medialis. Eight couples of active dancesport athletes (aged 20.50±2.75 yrs) were analyzed. Significant gender differences were found in rumba in the tibialis anterior (p≤0.05) and gastrocnemius medialis (p≤0.05). Based on the different activations, it is possible to establish possible mechanisms of injury, as well as tools for preventing injuries and improving sports performance.

scholarly journals Modeling of Muscle Activation from Electromyography Recordings in Patients with Cerebral Palsy

2018 ◽  
Vol 8 (12) ◽  
pp. 2345
Author(s):  
Susmita Roy ◽  
Ana Alves-Pinto ◽  
Renée Lampe
Keyword(s):  
Cerebral Palsy ◽  
Reference Values ◽  
Muscle Activation ◽  
Muscle Force ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Force Modeling ◽  
Lower Extremity Muscle ◽  
Musculus Gastrocnemius ◽  
Parameter Dependent

The present study estimated muscle activation from electromyographic (EMG) recordings in patients with cerebral palsy (CP) during cycling on an ergometer. This could be used as an input to the modeling of muscle force following the neuromusculoskeletal modeling technique which can help to understand the alterations in neuromotor processes underlying disabilities in CP. EMG signals of lower extremity muscle activity from 14 adult patients with CP and 10 adult healthy participants were used here to derive muscle activation. With a self developed EMG system, signals from the following muscles were recorded: Musculus tibialis anterior, Musculus gastrocnemius, Musculus rectus femoris, and Musculus biceps femoris. Collected EMG signals were mathematically transformed into muscle activation following a parameter dependent and a nonlinear transformation. Muscle activation values from patients with CP were compared to equivalent reference values obtained from healthy controls. Muscle activation calculated at specific foot positions deviated clearly from reference values. The deviation was larger for patients with higher degree of spasticity. Observations underline the need of muscle force modeling during cycling for individualized cycling training for rehabilitation strategy.

scholarly journals Effect of Hip Flexion Angle on the Hamstring to Quadriceps Strength Ratio

Sports ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 43
Author(s):  
Eleftherios Kellis ◽  
Athanasios Ellinoudis ◽  
and Nikolaos Kofotolis
Keyword(s):  
Muscle Activation ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Knee Extension ◽  
Quadriceps Strength ◽  
Flexion Angle ◽  
Electromyographic Activity ◽  
H:Q Ratio ◽  
Hip Flexion ◽  
Selection Of

The purpose of this study was to compare the hamstring to quadriceps ratio (H:Q) obtained from three different hip flexion angles. Seventy-three young athletes performed maximum isokinetic concentric and eccentric knee extension and flexion efforts at 60 °·s−1 and 240 °·s−1 from hip flexion angles of 90°, 60°, and 120°. The conventional (concentric to concentric), functional (eccentric to concentric) and mixed (eccentric at 30 °·s−1 to concentric torque at 240 °·s−1) H: Q torque ratios and the electromyographic activity from the rectus femoris and biceps femoris were analyzed. The conventional H:Q ratios and the functional H:Q ratios at 60 °·s−1 did not significantly differ between the three testing positions (p > 0.05). In contrast, testing from the 90° hip flexion angle showed a greater functional torque ratio at 240 °·s−1 and a mixed H:Q torque ratio compared with the other two positions (p < 0.05). The hip flexion angle did not influence the recorded muscle activation signals (p > 0.05). For the range of hip flexion angles tested, routine isokinetic assessment of conventional H:Q ratio and functional H:Q ratio at slow speed is not angle-dependent. Should assessment of the functional H:Q ratio at fast angular velocity or the mixed ratio is required, then selection of hip flexion angle is important.

scholarly journals Quadriceps and hamstrings coactivation in exercises used in prevention and rehabilitation of hamstring strain injury in young soccer players

2019 ◽  
Author(s):  
Gonzalo Torres ◽  
David Chorro ◽  
Archit Navandar ◽  
Javier Rueda ◽  
Luís Fernández ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Activation Pattern ◽  
Male Youth ◽  
Maximum Voluntary Isometric Contraction ◽  
Hamstring Strain ◽  
Exercise Muscle ◽  
Injury Recovery

AbstractThis study aimed to study the co-activation of hamstring-quadriceps muscles during submaximal strength exercises without the use of maximum voluntary isometric contraction testing and compare (i) the inter-limb differences in muscle activation, (ii) the intra-muscular group activation pattern, and (iii) the activation during different phases of the exercise. Muscle activation was recorded by surface electromyography of 19 elite male youth players. Participants performed five repetitions of the Bulgarian squat, lunge and the squat with an external load of 10 kg. Electrical activity was recorded for the rectus femoris, vastus medialis, vastus lateralis, biceps femoris and semitendinosus. No significant inter-limb differences were found (F1, 13=619; p=0.82; partial η2=0.045). Significant differences were found in the muscle activation between different muscles within the muscle group (quadriceps and hamstrings) for each of the exercises: Bulgarian squat (F1,18=331: p<0.001; partial η2=0.80), lunge (F4,72=114.5; p<0.001; partial η2=0.86) and squat (F1,16=247.31; p<0.001; partial η2=0.93).Differences were found between the concentric, isometric and eccentric phases of each of the exercises (F2, 26=52.27; p=0.02; partial η2=0.80). The existence of an activation pattern of each of the muscles in the three proposed exercises could be used for muscle assessment and as a tool for injury recovery.

scholarly journals Electromyographic responses to Nordic curl and prone leg curl exercises in football players

2021 ◽  
Vol 25 (5) ◽  
pp. 288-298
Author(s):  
Murat Çilli ◽  
Merve N. Yasar ◽  
Onur Çakir
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Total Duration ◽  
Rectus Femoris ◽  
Random Order ◽  
Biceps Femoris ◽  
Activation Rate ◽  
Significant Difference ◽  
Activation Rates ◽  
Short Time

Background and Study Aim. The aim of this study is to examine the electromyographic responses to Nordic curl and prone leg curl exercises, having two different mechanics. Material and Methods. The athletes performed the prone leg curl and Nordic curl exercises in random order, 6 repetitions each. Electromyographic data of semimemranosus, semitendinosus, biceps femoris and rectus femoris muscles were recorded by 8-channel electromyography in order to examine the muscle responses to exercises. Total duration of exercise, cumulative integrated electromyographic values and muscle activation rates in 5 different intensity zones determined according to MVC% values have been compared. Results. Prone leg curl exercise occurred in less time than Nordic curl exercise. According to the cumulative integrated electromyography data results, all muscles showed similar muscle activation in both exercises. Comparing the muscle activation rates in the five intensity zones, more muscle activity was observed for Nordic curl exercise in the first intensity zone, while prone leg curl exercise was more active in the third and fourth zones. During the prone leg curl exercise, the muscle activation rate of the dominant leg is higher in the first intensity zone, whereas the non-dominant leg in the fourth intensity zone has a higher muscle activation. During the Nordic curl exercise, the muscle activation rates of the dominant leg in the first and fifth intensity zones are higher, whereas the nondominant leg in the fourth intensity zone is higher. Conclusions. Prone leg curl exercises can be preferred in order to stimulate high muscle activation in a short time. Comparing the two exercises there was no significant difference in muscle activity in dominant and nondominant legs.

scholarly journals The Effect of Step Width on Muscle Contributions to Body Mass Center Acceleration During the First Stance of Sprinting

2021 ◽  
Vol 9 ◽  
Author(s):  
Ruoli Wang ◽  
Laura Martín de Azcárate ◽  
Paul Sandamas ◽  
Anton Arndt ◽  
Elena M. Gutierrez-Farewik
Keyword(s):  
Lower Limb ◽  
Sagittal Plane ◽  
Center Of Mass ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Gluteus Medius ◽  
Biceps Femoris ◽  
The Body ◽  
Step Width ◽  
Acceleration Analysis

BackgroundAt the beginning of a sprint, the acceleration of the body center of mass (COM) is driven mostly forward and vertically in order to move from an initial crouched position to a more forward-leaning position. Individual muscle contributions to COM accelerations have not been previously studied in a sprint with induced acceleration analysis, nor have muscle contributions to the mediolateral COM accelerations received much attention. This study aimed to analyze major lower-limb muscle contributions to the body COM in the three global planes during the first step of a sprint start. We also investigated the influence of step width on muscle contributions in both naturally wide sprint starts (natural trials) and in sprint starts in which the step width was restricted (narrow trials).MethodMotion data from four competitive sprinters (2 male and 2 female) were collected in their natural sprint style and in trials with a restricted step width. An induced acceleration analysis was performed to study the contribution from eight major lower limb muscles (soleus, gastrocnemius, rectus femoris, vasti, gluteus maximus, gluteus medius, biceps femoris, and adductors) to acceleration of the body COM.ResultsIn natural trials, soleus was the main contributor to forward (propulsion) and vertical (support) COM acceleration and the three vasti (vastus intermedius, lateralis and medialis) were the main contributors to medial COM acceleration. In the narrow trials, soleus was still the major contributor to COM propulsion, though its contribution was considerably decreased. Likewise, the three vasti were still the main contributors to support and to medial COM acceleration, though their contribution was lower than in the natural trials. Overall, most muscle contributions to COM acceleration in the sagittal plane were reduced. At the joint level, muscles contributed overall more to COM support than to propulsion in the first step of sprinting. In the narrow trials, reduced COM propulsion and particularly support were observed compared to the natural trials.ConclusionThe natural wide steps provide a preferable body configuration to propel and support the COM in the sprint starts. No advantage in muscular contributions to support or propel the COM was found in narrower step widths.

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