scholarly journals Bilateral differences in hamstring coordination in previously injured elite athletes

2020 ◽  
Vol 128 (3) ◽  
pp. 688-697
Author(s):  
Simon Avrillon ◽  
François Hug ◽  
Gaël Guilhem
Keyword(s):  
Biceps Femoris ◽  
Hamstring Injury ◽  
Muscle Coordination ◽  
Injured Limb ◽  
Cross Sectional ◽  
Hamstring Muscles ◽  
History Of ◽  
Total Knee ◽  
Bilateral Differences ◽  
Lower Contribution

Hamstring strain injuries (HSIs) involve tissue disruption and pain, which can trigger long-term adaptations of muscle coordination. However, little is known about the effect of previous HSIs on muscle coordination and in particular, after the completion of rehabilitation and in the absence of symptoms. This study aimed to determine if elite athletes with a prior unilateral HSI have bilateral differences in coordination between the hamstring muscle heads after returning to sport. Seventeen athletes with a unilateral history of biceps femoris (BF) injury participated in the experiment. Surface electromyography was recorded from three hamstring muscles [BF, semimembranosus (SM), and semitendinosus] during submaximal isometric torque-matched tasks at 20% and 50% of maximal voluntary contraction. The product of normalized electromyographic amplitude with functional physiological cross-sectional area (PCSA) and moment arm was considered as an index of individual muscle torque. The contribution of the injured muscle to total knee flexion torque was lower in the injured than the uninjured limb (−5.6 ± 10.2%, P = 0.038). This reduced contribution of BF was compensated by a higher contribution of the SM muscle in the injured limb (+5.6 ± 7.5%, P = 0.007). These changes resulted from a lower contribution of PCSA from the injured muscle (BF) and a larger contribution of activation from an uninjured synergist muscle (SM). In conclusion, bilateral differences in coordination were observed in previously injured athletes despite the completion of rehabilitation. Whether these bilateral differences in hamstring coordination could constitute an intrinsic risk factor that contributes to the high rate of hamstring injury recurrence remains to be investigated. NEW & NOTEWORTHY We used an experimental approach, combining the assessment of muscle activation, physiological cross-sectional area, and moment arm to estimate force-sharing strategies among hamstring muscles during isometric knee flexions. We tested athletes with a history of hamstring injury. We observed a lower contribution of the injured biceps femoris to the total knee flexor torque in the injured limb than in the contralateral limb. This decreased contribution was mainly due to selective atrophy of the injured biceps femoris muscle and was compensated by an increased activation of the semimembranosus muscle.

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.

Comparison of Electromyographic Activity During Hip Extension Exercises Under Gravitational or Inertial Loading Conditions

2021 ◽  
pp. 194173812110114
Author(s):  
Rodrigo Martín-San Agustín ◽  
Lorenzo Castillo-Ballesta ◽  
Javier Llobat Sancho ◽  
Rubén Esbri-Navarro ◽  
Mariana Sánchez-Barbadora
Keyword(s):  
Training Programs ◽  
Hamstring Injury ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Loading Conditions ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Hamstring Muscles ◽  
Inertial Loading ◽  
Hip Extension

Background: Hamstring injury prevention programs include strengthening, especially eccentric exercises using both gravitational and inertial loading. Inertial exercises are characterized by eccentric contractions of high intensity and velocity. This study aimed to analyze the muscular activation of the biceps femoris (BF), semitendinosus (ST), gluteus maximus (GM), and gracilis (GC) muscles during hip extension (HE) exercises performed under both gravitational and inertial loading conditions. Hypothesis: Inertial training would generate a greater activation of HE muscles than gravitational training. Study Design: Cross-sectional study. Level of Evidence: Level 4. Methods: Fifteen resistance-trained men performed the unilateral straight knee bridge (SKB), 45° of HE, and stiff-leg deadlift (SDL) exercises under gravitational and inertial loading conditions. Concentric and eccentric phases were identified with a linear encoder. Differences between load types, exercises, and their interaction were examined to establish the electromyographic (EMG) activity of each muscle and BF/ST ratio. Results: In the concentric phase, inertial loading showed a higher normalized EMG than gravitational loading for BF, ST, and GM. SKB and HE activated BF and ST between 9.6% and 24.3% more than SDL. In the eccentric phase, the inertial modality achieved greater GM activation than the gravitational form (18.1%). BF activation was increased with HE and SKB as compared with SDL (24.4% and 16.4%, respectively), while ST activation was likewise enhanced with HE as compared with SDL (15.1%). Conclusion: Inertial training is more effective than gravitational training for the concentric activation of the hamstring muscles while SDL showed lower hamstring activation than HE and SKB. Therefore, HE and SKB with inertial loading should be taken into account in hamstring training programs. Clinical Relevance: Inertial training is more effective than gravitational training for the concentric activation of the hamstring muscles. HE and SKB with inertial loading should be taken into account in hamstring training programs.

scholarly journals Acute Static Stretching Results in Muscle-Specific Alterations amongst the Hamstring Muscles

Sports ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 119
Author(s):  
Manon Riccetti ◽  
Jules Opplert ◽  
Joao L. Q. Durigan ◽  
Carole Cometti ◽  
Nicolas Babault
Keyword(s):  
Biceps Femoris ◽  
Hamstring Injury ◽  
Myotendinous Junction ◽  
Static Stretching ◽  
Semitendinosus Muscle ◽  
Biceps Femoris Muscle ◽  
Passive Torque ◽  
Hamstring Muscles ◽  
Long Head ◽  
Femoris Muscle

This study aimed to explore the acute effects of static stretching on the musculotendinous properties of two hamstring muscles. Twelve male volunteers underwent two testing sessions. One session was dedicated to the evaluation of the semitendinosus muscle before (PRE) and after (POST) static stretching (five sets of 30-s stretching), and the other session similarly explored the long head of biceps femoris muscle. In addition to the displacement of the myotendinous junction (MTJ), passive torque and maximal voluntary isometric torque (MVIT) were evaluated. MVIT (−8.3 ± 10.2%, p = 0.0036, d = 0.497) and passive torque (−28.4 ± 16.9%, p = 0.0003, d = 1.017) were significantly decreased POST stretching. PRE stretching, MTJ displacement was significantly greater for semitendinosus muscle than biceps femoris muscle (27.0 ± 5.2 vs. 18.6 ± 3.6, p = 0.0011, d = 1.975). After the stretching procedure, greater MTJ displacement relative changes were observed for biceps femoris muscle as compared to semitendinosus muscle (22.4 ± 31.6 vs. −8.4 ± 17.9, p = 0.0167, d = 1.252). Because of the smaller MTJ displacement PRE stretching and greater alteration POST stretching in biceps femoris muscles, the present study demonstrated muscle-specific acute responses of hamstring muscles during stretching. Although stretching acutely impairs torque production, the passive torque reduction and alteration of MTJ displacement might impact hamstring injury prevention.

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.

Rate of Torque and Electromyographic Development During Anticipated Eccentric Contraction Is Lower in Previously Strained Hamstrings

2012 ◽  
Vol 41 (1) ◽  
pp. 116-125 ◽  
Author(s):  
David A. Opar ◽  
Morgan D. Williams ◽  
Ryan G. Timmins ◽  
Nuala M. Dear ◽  
Anthony J. Shield
Keyword(s):  
Eccentric Contraction ◽  
Biceps Femoris ◽  
Injured Limb ◽  
Myoelectrical Activity ◽  
Recreational Athletes ◽  
Hamstring Strain ◽  
History Of ◽  
Long Head ◽  
Biceps Femoris Long Head ◽  
Torque Development

Background: The effect of prior strain injury on myoelectrical activity of the hamstrings during tasks requiring high rates of torque development has received little attention. Purpose: To determine if recreational athletes with a history of unilateral hamstring strain injury will exhibit lower levels of myoelectrical activity during eccentric contraction, rate of torque development (RTD), and impulse (IMP) at 30, 50, and 100 milliseconds after the onset of myoelectrical activity or torque development in the previously injured limb compared with the uninjured limb. Study Design: Case control study; Level of evidence, 3. Methods: Twenty-six recreational athletes were recruited. Of these, 13 athletes had a history of unilateral hamstring strain injury (all confined to biceps femoris long head), and 13 had no history of hamstring strain injury. Following familiarization, all athletes undertook isokinetic dynamometry testing and surface electromyography (integrated EMG; iEMG) assessment of the biceps femoris long head and medial hamstrings during eccentric contractions at −60 and −180 deg·s−1. Results: In the injured limb of the injured group, compared with the contralateral uninjured limb, RTD and IMP was lower during −60 deg·s−1 eccentric contractions at 50 milliseconds (RTD: injured limb, 312.27 ± 191.78 N·m·s−1 vs uninjured limb, 518.54 ± 172.81 N·m·s−1, P = .008; IMP: injured limb, 0.73 ± 0.30 N·m·s vs uninjured limb, 0.97 ± 0.23 N·m·s, P = .005) and 100 milliseconds (RTD: injured limb, 280.03 ± 131.42 N·m·s−1 vs uninjured limb, 460.54 ± 152.94 N·m·s−1, P = .001; IMP: injured limb, 2.15 ± 0.89 N·m·s vs uninjured limb, 3.07 ± 0.63 N·m·s, P < .001) after the onset of contraction. Biceps femoris long head muscle activation was lower at 100 milliseconds at both contraction speeds (–60 deg·s−1, normalized iEMG activity [×1000]: injured limb, 26.25 ± 10.11 vs uninjured limb, 33.57 ± 8.29, P = .009; –180 deg·s−1, normalized iEMG activity [×1000]: injured limb, 31.16 ± 10.01 vs uninjured limb, 39.64 ± 8.36, P = .009). Medial hamstring activation did not differ between limbs in the injured group. Comparisons in the uninjured group showed no significant between limbs difference for any variables. Conclusion: Previously injured hamstrings displayed lower RTD and IMP during slow maximal eccentric contraction compared with the contralateral uninjured limb. Lower myoelectrical activity was confined to the biceps femoris long head. Regardless of whether these deficits are the cause of or the result of injury, these findings could have important implications for hamstring strain injury and reinjury. Particularly, given the importance of high levels of muscle activity to bring about specific muscular adaptations, lower levels of myoelectrical activity may limit the adaptive response to rehabilitation interventions and suggest that greater attention be given to neural function of the knee flexors after hamstring strain injury.

Suicidal Ideation Among Medical Students in Dammam, Saudi Arabia

Crisis ◽  
2020 ◽  
pp. 1-6
Author(s):  
Mohammed Madadin ◽  
Ritesh G. Menezes ◽  
Maha A. Alassaf ◽  
Abdulaziz M. Almulhim ◽  
Mahdi S. Abumadini ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Medical Students ◽  
Suicidal Ideation ◽  
General Health Questionnaire ◽  
Cross Sectional Study ◽  
Eastern Province ◽  
Cross Sectional ◽  
The Past ◽  
Depression Subscale ◽  
History Of

Abstract. Background: Medical students are at high risk of suicidal ideation. Aim: We aimed to obtain information on suicidal ideation among medical students in Dammam located in the Eastern Province of Saudi Arabia. Method: This cross-sectional study was conducted at the College of Medicine affiliated with Imam Abdulrahman Bin Faisal University in the Eastern Province of Saudi Arabia. Suicidal ideation in the past 12 months was assessed based on responses to four questions in the depression subscale of the General Health Questionnaire 28 (GHQ-28). In addition, data were collected to examine the association of suicidal ideation with various factors. Results: We found that 1 in 3 medical students in the study had suicidal ideation in the past 12 months, while around 40% had lifetime suicidal ideation. Suicidal ideation was associated with feelings of parental neglect, history of physical abuse, and dissatisfaction with academic performance. Limitations: The cross-sectional nature of this study limits its ability to determine causality regarding suicidal ideation. Conclusion: These rates are considerably high when compared with rates from studies in other countries around the world. This study provides a reference in the field of suicidology for this region of Saudi Arabia.

External Validity of SCORS-G Ratings of Thematic Apperception Test Narratives in a Sample of Outpatients and Inpatients

2015 ◽  
Vol 36 (1) ◽  
pp. 58-81 ◽  
Author(s):  
Michelle B. Stein ◽  
Jenelle Slavin-Mulford ◽  
Caleb J. Siefert ◽  
Samuel Justin Sinclair ◽  
Michaela Smith ◽  
...  
Keyword(s):  
Life Events ◽  
Psychiatric Hospitalization ◽  
Clinical Care ◽  
Thematic Apperception Test ◽  
Clinical Samples ◽  
Cross Sectional ◽  
Conduct Disordered ◽  
Global Ratings ◽  
Thematic Apperception ◽  
History Of

Abstract. The Social Cognition and Object Relations Scale-Global Ratings Method (SCORS-G; Stein, Hilsenroth, Slavin-Mulford, & Pinsker-Aspen, 2011 ) is a reliable system for coding narrative data, such as Thematic Apperception Test (TAT) stories. This study employs a cross-sectional, correlational design to examine associations between SCORS-G dimensions and life events in two clinical samples. Samples were composed of 177 outpatients and 57 inpatients who completed TAT protocols as part of routine clinical care. Two experienced raters coded narratives with the SCORS-G. Data on the following clinically relevant life events were collected: history of psychiatric hospitalization, suicidality, self-harming behavior, drug/alcohol abuse, conduct-disordered behavior, trauma, and education level. As expected, the clinical life event variable associated with the largest number of SCORS-G dimensions was Suicidality. Identity and Coherence of Self was related to self-harm history across samples. Emotional Investment in Relationships and Complexity of Representations were also associated with several life events. Clinical applications, limitations of the study, and future directions are reviewed.

DYSLIPIDEMIA IN THYROID DISORDERS

2020 ◽  
Vol 4 (7) ◽  
Author(s):  
Kashish Narula ◽  
Narendra Kumar Dara ◽  
Shyam Lal Meena
Keyword(s):  
Lipid Metabolism ◽  
Thyroid Dysfunction ◽  
Cross Sectional Study ◽  
Control Group ◽  
Thyroid Disorders ◽  
Cross Sectional ◽  
Carbohydrate And Lipid Metabolism ◽  
History Of ◽  
Thyroid Profile ◽  
Basal Energy Expenditure

Background: Thyroid hormones influence nearly all major metabolic pathways. Their most obvious and well-known action is the increase in basal energy expenditure obtained by acting on protein, carbohydrate and lipid metabolism. The lipid metabolism is more influenced by the thyroid hormone. Methods: A cross-sectional study was conducted on 100 patients with suspicion of thyroid disorders were taken as cases. One hundred patients with normal thyroid profile and no history of other chronic diseases were taken as control group. Results: The serum TC, TG and LDL levels in hypothyroid individuals (both overt and subclinical) were significantly higher than euthyroid subjects but the levels were comparable between hyperthyroid and euthyroid group. Conclusion: Dyslipidemias are associated with thyroid disorders, so biochemical screening for thyroid dysfunction in all dyslipidemic patients. Therefore, patients presenting with dyslipidemia are recommended for investigation to explore thyroid dysfunction. Keywords: Thyroid profile, Total cholesterol, Triglycerides and LDL

Demographic Factors Associated with Congenital Malformations Among Young Infants in Fallujah Maternity and Children Hospital, Fallujah City, Iraq

2020 ◽  
pp. 1-5
Author(s):  
Samira T.Abdulghani ◽  
Samira T.Abdulghani
Keyword(s):  
Developing Countries ◽  
Congenital Anomalies ◽  
Prevalence Rate ◽  
Gestational Hypertension ◽  
Heart Defects ◽  
Demographic Factors ◽  
Cross Sectional ◽  
Factors Associated ◽  
Young Infants ◽  
History Of

Background: Congenital anomalies are a major cause of infant morbidity and mortality in developing countries including our country. Registries and data on these anomalies are still primitive and poorly collated. In this study we aimed to assess the important demographic factors associated with the development of congenital anomalies. Methods: This was a cross-sectional hospital-based study involving 880 infants in the 1st year of life registered in the birth defect unit in Fallujah Maternity and Children Hospital in the period between 1st of January 2017 to the 31st of December 2019. The prevalence rate, the pattern of anomalies and the factors associated with their occurrence were determined. Results: The prevalence rate of the group enrolled in this study was 31/1000 total births, congenital heart defects was the commonest followed by central nervous system anomalies, 58% of the infants were males, 65% had ≥ 2.5 kg birth weight & 95% were singletons. Family history of congenital anomalies was found in 31.25% of cases. The largest group of mothers (55.7%) were 21-30 years old & 92.5% of fathers were less than 45 years old. Parental consanguinity reported in 64.3% of the total cases. Only 4.5% of mothers reported history of fever during pregnancy, and none of them had history of exposure to x-ray or teratogenic drug use. Gestational hypertension was reported in 10% of the total (880) mothers, hypertension and diabetes mellitus in 0.3%, while hepatitis C, hepatitis B, toxoplasmosis and epilepsy, each was reported in only one mother (0.1% of the total). Regarding the outcome of pregnancy, 66.6% were live births, 24.2% were abortions and 9.2% were stillbirths. History of previous abortions was reported in 22% of cases. Urban residents accounted for 63% of the families of congenitally abnormal infants while 37% were rural. Conclusion: Congenital anomalies are still a major cause for concern and tension in Fallujah society, there is serious need to establish a surveillance and good statistical system for congenital anomalies and efforts should be made to raise awareness of their occurrence and the associated risk factors in Iraq and other developing countries.

Uncertainty about cellulitis and unmet patient information needs: a mixed methods study

2018 ◽  
Vol 68 (suppl 1) ◽  
pp. bjgp18X697349
Author(s):  
Anna Lalonde ◽  
Emma Teasdale ◽  
Ingrid Muller ◽  
Joanne Chalmers ◽  
Peter Smart ◽  
...  
Keyword(s):  
Mixed Methods ◽  
Information Needs ◽  
Qualitative Data ◽  
Information Provision ◽  
Mixed Methods Study ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Face To Face ◽  
Patient Information Needs ◽  
History Of

BackgroundCellulitis is a common painful infection of the skin and underlying tissues that recurs in approximately a third of cases. Patients’ ability to recover from cellulitis or prevent recurrence is likely to be influenced by their understanding of the condition.AimTo explore patients’ perceptions of cellulitis and their information needs.MethodMixed methods study comprising semi-structured, face-to-face interviews and cross-sectional survey, recruiting through primary care, secondary care and advertising. Adults aged 18 or over with a history of cellulitis (first or recurrent) were invited to complete a survey, take part in an interview or both. Qualitative data was analysed thematically.ResultsThirty interviews were conducted between August 2016 and July 2017. Qualitative data revealed low prior awareness of cellulitis, uncertainty around diagnosis, concern/surprise at the severity of cellulitis, and perceived insufficient information provision. People were surprised they had never heard of the condition and that they had not received advice or leaflets giving self-care information. Some sought information from the internet and found this bewildering. Two hundred and forty surveys were completed (response rate 17%). These showed that, while most people received information on the treatment of cellulitis (60.0%, n = 144), they reported receiving no information about causes (60.8%, n = 146) or prevention of recurrence (73.3%, n = 176).ConclusionThere is a need for provision of basic information for people with cellulitis, particularly being informed of the name of their condition, how to manage acute episodes, and how to reduce risk of recurrence.

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