scholarly journals Muscle Activation Differences During Eccentric Hamstring Exercises

2020 ◽  
pp. 194173812093864
Author(s):  
Sonay Guruhan ◽  
Nihan Kafa ◽  
Zeynep B. Ecemis ◽  
Nevin A. Guzel
Keyword(s):  
Muscle Activation ◽  
Critical Role ◽  
Biceps Femoris ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Maximum Voluntary Isometric Contraction ◽  
Hamstring Muscles ◽  
Limb Injuries ◽  
Exercise Type ◽  
Muscular Activation

Background: The hamstring muscles play a critical role in the prevention of lower limb injuries. However, it is still unclear which exercises are more effective in terms of muscle activation. Hypothesis: In healthy individuals, there are differences between muscular activations of the biceps femoris (BF), semitendinosus (ST), and semimembranosus (SM) muscles during eccentric hamstring exercises. Study Design: Cross-sectional. Level of Evidence: Level 2. Methods: A total of 31 healthy participants (18 male; mean age, 22.5 years; SD, 3.1) were included in this study. The maximum voluntary isometric contraction of the hamstring muscles was measured using an isokinetic dynamometer. The participants were asked to perform one of the following exercises randomly (3 repetitions each): stiff-leg deadlift (SLDL), unilateral stiff-leg deadlift (USLDL), Nordic hamstring exercise (NHE), and ball leg curl (BLC). Activation of the BF, ST, and SM muscles was measured using surface electromyography during the exercises. In the statistical analysis of this study, factorial analysis of variance was used to compare the effects of each exercise on the muscle groups and to analyze which exercise type was more effective for each muscle group. Results: The NHE led to higher muscle activation than the other exercises ( P < 0.001). When exercise type and muscle interaction were examined, SM activation was lower than BF ( P = 0.04) and ST ( P = 0.001) during NHE ( P < 0.05). The highest level of muscular activation was recorded during the NHE in both male and female participants. Conclusion: The NHE may be the most effective exercise for the hamstring muscles as it leads to greater muscle activation. SLDL, USLDL, and BLC exercises may be preferred at the beginning of strength training programs since they lead to lower muscular activation compared with the NHE. Clinical Relevance: To select the optimum hamstring exercise, it is important to know the activation levels of the hamstring muscles during different eccentric exercises.

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

scholarly journals Muscle Coactivation Before and After the Impact Phase of Running Following Isokinetic Fatigue

2011 ◽  
Vol 46 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Eleftherios Kellis ◽  
Andreas Zafeiridis ◽  
Ioannis G. Amiridis
Keyword(s):  
Muscle Activation ◽  
Biceps Femoris ◽  
Knee Extension ◽  
Knee Extensors ◽  
Training Experience ◽  
Cross Sectional ◽  
Muscle Activation Patterns ◽  
Strength Capacity ◽  
Before And After ◽  
The Impact

Abstract Context: The effects of fatigue on impact loading during running are unclear, with some authors reporting increased impact forces and others reporting decreased forces. Objective: To examine the effects of isokinetic fatigue on muscle cocontraction ratios about the knee and ankle during running. Design: Cross-sectional study. Setting: Neuromechanics laboratory. Patients or Other Participants: Female middle-distance runners (age  =  21.3 ± 1.93 years) with at least 5 years of training experience. Intervention(s): Participants ran on the treadmill at 3.61 m/s before and immediately after the fatigue protocol, which consisted of consecutive, concentric knee extension-flexion at 120°/s until they could no longer produce 30% of the maximum knee-extension moment achieved in the familiarization session for 3 consecutive repetitions. Main Outcome Measure(s): Electromyographic (EMG) amplitude of the vastus medialis (VM), biceps femoris (BF), gastrocnemius (GAS), and tibialis anterior (TA) was recorded using surface electrodes. Agonist∶antagonist EMG ratios for the knee (VM∶BF) and ankle (GAS∶TA) were calculated for the preactivation (PR), initial loading response (LR1), and late loading response (LR2) phases of running. Hip-, knee-, and ankle-joint angular displacements at initial foot contact were obtained from 3-dimensional kinematic tracings. Results: Fatigue did not alter the VM∶BF EMG ratio during the PR phase (P &gt; .05), but it increased the ratio during the LR1 phase (P &lt; .05). The GAS∶TA EMG ratio increased during the LR1 phase after fatigue (P &lt; .05) but remained unchanged during the PR and LR2 phrases (P &gt; .05). Conclusions: The increased agonist EMG activation, coupled with reduced antagonist EMG activation after impact, indicates that the acute decrease in muscle strength capacity of the knee extensors and flexors results in altered muscle-activation patterns about the knee and ankle before and after foot impact.

Peroneal Activation Deficits in Persons with Functional Ankle Instability

2009 ◽  
Vol 37 (5) ◽  
pp. 982-988 ◽  
Author(s):  
Riann M. Palmieri-Smith ◽  
J. Ty Hopkins ◽  
Tyler N. Brown
Keyword(s):  
Ankle Sprain ◽  
Muscle Activation ◽  
Ankle Instability ◽  
Cross Sectional Study ◽  
Functional Ankle Instability ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Emg Amplitude ◽  
Muscle Inhibition ◽  
Arthrogenic Muscle Inhibition

Background Functional ankle instability (FAI) may be prevalent in as many as 40% of patients after acute lateral ankle sprain. Altered afference resulting from damaged mechanoreceptors after an ankle sprain may lead to reflex inhibition of surrounding joint musculature. This activation deficit, referred to as arthrogenic muscle inhibition (AMI), may be the underlying cause of FAI. Incomplete activation could prevent adequate control of the ankle joint, leading to repeated episodes of instability. Hypothesis Arthrogenic muscle inhibition is present in the peroneal musculature of functionally unstable ankles and is related to dynamic peroneal muscle activity. Study Design Cross-sectional study; Level of evidence, 3. Methods Twenty-one (18 female, 3 male) patients with unilateral FAI and 21 (18 female, 3 male) uninjured, matched controls participated in this study. Peroneal maximum H-reflexes and M-waves were recorded bilaterally to establish the presence or absence of AMI, while electromyography (EMG) recorded as patients underwent a sudden ankle inversion perturbation during walking was used to quantify dynamic activation. The H:M ratio and average EMG amplitudes were calculated and used in data analyses. Two-way analyses of variance were used to compare limbs and groups. A regression analysis was conducted to examine the association between the H:M ratio and the EMG amplitudes. Results The FAI patients had larger peroneal H:M ratios in their nonpathological ankle (0.399 ± 0.185) than in their pathological ankle (0.323 ± 0.161) (P = .036), while no differences were noted between the ankles of the controls (0.442 ± 0.176 and 0.425 ± 0.180). The FAI patients also exhibited lower EMG after inversion perturbation in their pathological ankle (1.7 ± 1.3) than in their uninjured ankle (EMG, 3.3 ± 3.1) (P < .001), while no differences between legs were noted for controls (P > .05). No significant relationship was found between the peroneal H:M ratio and peroneal EMG (P > .05). Conclusion Arthrogenic muscle inhibition is present in the peroneal musculature of persons with FAI but is not related to dynamic muscle activation as measured by peroneal EMG amplitude. Reversing AMI may not assist in protecting the ankle from further episodes of instability; however dynamic muscle activation (as measured by peroneal EMG amplitude) should be restored to maximize ankle stabilization. Dynamic peroneal activity is impaired in functionally unstable ankles, which may contribute to recurrent joint instability and may leave the ankle vulnerable to injurious loads.

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 Is There Any Association Between Neurodegenerative Diseases and Periodontitis? A Systematic Review

2021 ◽  
Vol 13 ◽  
Author(s):  
María Olimpia Paz Alvarenga ◽  
Deborah Ribeiro Frazão ◽  
Isabella Gomes de Matos ◽  
Leonardo Oliveira Bittencourt ◽  
Nathália Carolina Fernandes Fagundes ◽  
...  
Keyword(s):  
Systematic Review ◽  
Neurodegenerative Diseases ◽  
Critical Role ◽  
Risk Of Bias ◽  
Significant Heterogeneity ◽  
Level Of Evidence ◽  
Pocket Depth ◽  
Cross Sectional ◽  
Probing Pocket Depth ◽  
Chronic Inflammatory Condition

Background: Neurodegenerative diseases are a group of progressive disorders that affect the central nervous system (CNS) such as Alzheimer, Parkinson, and multiple sclerosis. Inflammation plays a critical role in the onset and progression of these injuries. Periodontitis is considered an inflammatory disease caused by oral biofilms around the tooth-supporting tissues, leading to a systemic and chronic inflammatory condition. Thus, this systematic review aimed to search for evidence in the association between neurodegenerative disorders and periodontitis.Methods: This systematic review was registered at International Prospective Register of Systematic Reviews (PROSPERO) under the code CRD 42016038327. The search strategy was performed in three electronic databases and one gray literature source—PubMed, Scopus, Web of Science, and OpenGrey, based on the PECO acronym: observational studies in humans (P) in which a neurodegenerative disease was present (E) or absent (C) to observe an association with periodontitis (O). The Fowkes and Fulton checklist was used to critically appraise the methodological quality and the risk of bias of individual studies. The quality of evidence was assessed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE).Results: From 534 articles found, 12 were included, of which eight were case–control, three were cross-sectional, and one was a cohort, giving a total of 3,460 participants. All the included studies reported an association between some neurodegenerative diseases and periodontitis and presented a low risk of bias. According to the GRADE approach, the level of evidence of probing pocket depth was considered very low due to the significant heterogeneity across the studies' upgrading imprecision and inconsistency.Conclusions: Although all the included studies in this review reported an association between neurodegenerative diseases and periodontitis, the level of evidence was classified to be very low, which suggests a cautious interpretation of the results.

The Importance of Functional Hamstring/Quadriceps Ratios in Knee Osteoarthritis

2020 ◽  
Vol 29 (7) ◽  
pp. 866-870
Author(s):  
Özlem Aslan ◽  
Elif Balevi Batur ◽  
Jale Meray
Keyword(s):  
Patient Group ◽  
Critical Role ◽  
Peak Torque ◽  
Knee Extension ◽  
Cross Sectional Study ◽  
Control Group ◽  
Cross Sectional ◽  
Knee Oa ◽  
Hamstring Muscles ◽  
Grade 3

Context: Osteoarthritis (OA) is the most common chronic joint condition. Muscle dysfunction plays a critical role in the pathogenesis of knee OA. Objective: It has been suggested that the agonist–antagonist strength relationship for the knee may be better described by a functional hamstring/quadriceps (H/Q) ratio (Hconcentric/Qeccentric: the representative of knee flexion and Qeccentric/Hconcentric: the representative of knee extension). Therefore, in this study, the authors aimed to investigate this ratio and its importance for knee OA. Design: Cross-sectional study. Setting: Research clinic. Patients or Other Participant(s): Twenty healthy women and 20 women with grade 2 or grade 3 primer knee OA between the age of 50 and 80 years were included in this study. Intervention(s): Concentric and eccentric peak torque of quadriceps and hamstring muscles were evaluated for all individuals in patient and control groups with a Cybex isokinetic device. Functional H/Q ratio is calculated manually. Main Outcome Measure(s): Functional H/Q torque ratios were analyzed between the patients with OA and healthy individuals by using the isokinetic system. Results: The values of peak torque of hamstring concentric and eccentric and quadriceps concentric for the patient group were significantly lower than the control group (P < .05). No statistically important difference was found for quadriceps eccentric peak torque between 2 groups (P > .05). H/Q ratio for extension in the patient group was significantly higher than the control group (P < .05), whereas the H/Q ratio for flexion in the patient group was significantly lower than the control group (P < .05). Conclusion: This study showed the weakness of both quadriceps and hamstring muscles in patients with knee OA. The combination of functional H/Q ratio with hamstring and quadriceps muscles concentric and eccentric strength values can help to analyze the knee functions and develop preventive-therapeutic approaches for knee OA.

scholarly journals Evaluation of the Lower Limb Muscles’ Electromyographic Activity during the Leg Press Exercise and Its Variants: A Systematic Review

2020 ◽  
Vol 17 (13) ◽  
pp. 4626
Author(s):  
Isabel Martín-Fuentes ◽  
José M. Oliva-Lozano ◽  
José M. Muyor
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Muscular Activity ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Quadriceps Muscle ◽  
Electromyographic Activity ◽  
Full Extension ◽  
Cross Sectional ◽  
Leg Press

The aim of this study was to analyze the literature on muscle activation measured by surface electromyography (sEMG) of the muscles recruited when performing the leg press exercise and its variants. The Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to report this review. The search was carried out using the PubMed, Scopus, and Web of Science electronic databases. The articles selected met the following inclusion criteria: (a) a cross-sectional or longitudinal study design; (b) neuromuscular activation assessed during the leg press exercise, or its variants; (c) muscle activation data collected using sEMG; and (d) study samples comprising healthy and trained participants. The main findings indicate that the leg press exercise elicited the greatest sEMG activity from the quadriceps muscle complex, which was shown to be greater as the knee flexion angle increased. In conclusion, (1) the vastus lateralis and vastus medialis elicited the greatest muscle activation during the leg press exercise, followed closely by the rectus femoris; (2) the biceps femoris and the gastrocnemius medialis showed greater muscular activity as the knee reached full extension, whereas the vastus lateralis and medialis, the rectus femoris, and the tibialis anterior showed a decreasing muscular activity pattern as the knee reached full extension; (3) evidence on the influence of kinematics modifications over sEMG during leg press variants is still not compelling as very few studies match their findings.

scholarly journals Predictors of hospitalization and surgical intervention among patients with motorcycle injuries

2019 ◽  
Vol 4 (1) ◽  
pp. e000326
Author(s):  
Cary Fletcher ◽  
Derrick Mcdowell ◽  
Camelia Thompson ◽  
Kenneth James
Keyword(s):  
Lower Limb ◽  
Motor Vehicle ◽  
Average Length ◽  
Regional Hospital ◽  
Lower Limb Injuries ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Limb Injuries ◽  
Total Body ◽  
Motorcycle Crashes

BackgroundTo describe the distribution of injuries, hospitalization rates by body areas injured, and surgery-requiring admissions, and to identify independent predictors of admission to a regional hospital in Jamaica.MethodsA cross-sectional study was conducted among persons presenting to the St Ann’s Bay Regional Hospital in Jamaica (2016–2018) with injuries sustained from motorcycle crashes. A census was done of patients admitted to the surgery ward from the emergency room, as well as those referred to the Orthopaedic Outpatient Department. Trained members of the orthopedic team administered a pretested questionnaire within 24 hours of presenting to the orthopedic service to elicit data on sociodemographic characteristics, motor vehicle collision circumstance and motor bike specifications, physical injuries sustained and medical management, as well as compliance with legal requirements for riding a motorcycle. Associations between variables were examined using χ2 tests and logistic regression.ResultsThere were 155 participants in the study, and 75.3% of motorcyclists with injuries required admission. The average length of stay was approximately 10 days. Surgery was required for 71.6% of those admitted. Lower limb injuries constituted 55% of all injuries. The independent predictors for admission were alcohol use and total body areas involved. Motorcycle crash victims who used alcohol close to the time of crash were three times more likely to be admitted to hospital than those who did not consume alcohol. As the total body areas involved increased by one, there was a threefold increase in the likelihood of being admitted. Additionally, the greater the number of body areas involved, the greater was the likelihood of admission.DiscussionLower limb injuries are the most commonly reported injuries among victims of motorcycle crashes. Alcohol and total body areas involved are independent predictors of admission to hospital. In the planning of trauma delivery services, this information should be taken into account.Level of EvidenceLevel IV.

scholarly journals Coordination of hamstrings is individual specific and is related to motor performance

2018 ◽  
Vol 125 (4) ◽  
pp. 1069-1079 ◽  
Author(s):  
Simon Avrillon ◽  
Gaël Guilhem ◽  
Aude Barthelemy ◽  
François Hug
Keyword(s):  
Muscle Activation ◽  
Endurance Performance ◽  
Biceps Femoris ◽  
Significant Negative Correlation ◽  
Hamstring Injury ◽  
Muscle Endurance ◽  
Time To Exhaustion ◽  
Fascicle Length ◽  
Hamstring Muscles ◽  
Generating Capacity

The torque-sharing strategies between synergistic muscles may have important functional consequences. This study involved two experiments. The first experiment ( n = 22) aimed 1) to determine the relationship between the distribution of activation and the distribution of torque-generating capacity among the heads of the hamstring, and 2) to describe individual torque-sharing strategies and to determine whether these strategies are similar between legs. The second experiment ( n = 35) aimed to determine whether the distribution of activation between the muscle heads affects endurance performance during a sustained submaximal knee flexion task. Surface electromyography (EMG) was recorded from biceps femoris (BF), semimembranosus (SM), and semitendinosus (ST) during submaximal isometric knee flexions. Torque-generating capacity was estimated by measuring muscle volume, fascicle length, pennation angle, and moment arm. The product of the normalized EMG amplitude and the torque-generating capacity was used as an index of muscle torque. The distributions of muscle activation and of torque-generating capacity were not correlated significantly (all P > 0.18). Thus, there was a torque imbalance between the muscle heads (ST torque > BF and SM torque; P < 0.001), the magnitude of which varied greatly between participants. A significant negative correlation was observed between the imbalance of activation across the hamstring muscles and the time to exhaustion ( P < 0.001); i.e., the larger the imbalance of activation across muscles, the lower the muscle endurance performance. Torque-sharing strategies between the heads of the hamstrings are individual specific and related to muscle endurance performance. Whether these individual strategies play a role in hamstring injury remains to be determined. NEW & NOTEWORTHY The distribution of activation among the heads of the hamstring is not related to the distribution of torque-generating capacity. The torque-sharing strategies within hamstring muscles vary greatly between individuals but are similar between legs. Hamstring coordination affects endurance performance; i.e., the larger the imbalance of activation across the muscle heads, the lower the muscle endurance.

scholarly journals DIFFERENCES IN KNEE SENSORIMOTOR CONTROL BY PHYSICAL ACTIVITY LEVEL AND SEX

2019 ◽  
Vol 27 (1) ◽  
pp. 20-26
Author(s):  
Cristóbal San Martín-Mohr ◽  
Andrés Valladares ◽  
Iver Cristi ◽  
Francisco José Berral ◽  
Claudio Oyarzo ◽  
...  
Keyword(s):  
Physical Activity ◽  
Physical Activity Level ◽  
Muscle Activation ◽  
Muscle Tension ◽  
Control Level ◽  
Sensorimotor Control ◽  
Activity Level ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Healthy Men

ABSTRACT Objective: The aim of this study was to compare the differences in knee sensorimotor control between healthy men and women by measuring the joint position sense (JPS), sensation of muscle tension (steadiness), and onset of muscle activation (OMA). Methods: Twenty-four healthy women and 27 healthy men were tested. Knee sensorimotor control was assessed using the JPS test with electrogoniometers in 3 different ranges of motion, sensation of muscle tension using the isometric steadiness technique, and OMA against a mechanical perturbation. Each assessment was compared by sex, physical activity level, and right or left lower limb. Results: The men obtained better values in the JPS test between 90º and 60º and between 30º and 0º than the women. The subjects with higher levels of physical activity also showed better values, between 90º and 60º and between 30º and 0º. The best results for steadiness were found in the women and the subjects with higher levels of physical activity. In the OMA test, no significant differences were found in the studied variables. Conclusion: The results suggest that higher levels of physical activity may determine better sensorimotor control. Men have better articular sensation, and women have better muscle strength control. Level of evidence III, Cross sectional study.

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