Effect of Fatigue on the Core Muscle Endurance in Female Athletes With and Without Non-specific Chronic Low Back Pain

Purpose: Non-specific chronic low back pain (LBP) is the most common type of chronic LBP and a common debilitating condition, especially in athletes, that can also affect performance. The core muscles are necessary to create a stable level of support for sports performance and appropriate movements of all organs, and its deficiency is related to complications, such as LBP. This research aims to investigate the effect of a fatigue protocol on core muscle endurance in athletes with and without non-specific chronic LBP. Methods: A controlled laboratory study was conducted; 42 female athletes with and without non-specific chronic LBP were selected through convenience sampling method and divided into two groups with non-specific chronic LBP and without non-specific chronic LBP. McGill’s core endurance test was used to measure core muscle endurance. The measurements were done before and after the implementation of the functional core fatigue protocol (FCFP). SPSS software, version 22 and dependent t-tests and analysis of covariance (ANCOVA) were used to evaluate mean differences obtained in the two groups. The significance level was considered 95%, and the α level was ≤0.05. Results: The analysis of covariance (ANCOVA) showed a significant difference between the two groups with and without non-specific chronic LBP after performing the functional core fatigue protocol (FCFP) in McGill’s test scores in isometric flexion exercise (P=0.001), isometric extensor exercise (P=0.001), right side bridge (P=0.001) and left side bridge (P=0.001). In the post-test measurement, the endurance of the core muscles decreased in the LBP group. Conclusion: The findings revealed that fatigue can affect the core stability and reduce the core muscles endurance of female athletes with non-specific chronic LBP. Therefore, core muscle weakness can be recognized as a risk factor for chronic LBP, and in order to prevent this damage, it is recommended to strengthen this area in rehabilitation programs

Can lower extremity anatomical measures and core stability predict dynamic knee valgus in young men?

Introduction: Dynamic knee valgus (DKV) is a risk factor for lower extremity injuries such as anterior cruciate ligament and patellofemoral pain syndrome. Purpose of the current study was to investigate the relationship between lower extremity anatomical measures (LEAM) and core stability with DKV during the single-leg squat. Methods: Thirty healthy men aged between 18 and 28 years participated in this cross-sectional biomechanical study. DKV was assessed using a 6-camera motion analysis system during a single-leg squat task. Anteversion of hip, hip internal and external rotation, Q-angle, knee hyperextension, tibial torsion, tibia vara, plantar arch index, and core stability were measured using standard clinical procedures. To predict DKV, a multiple linear regression model was used. Result: The stability index negatively and plantar arch index positively predicted greater DKV during the single-leg squat task (P = 0.001 and P = 0.09, respectively). Research variables together predicted 82% of the variance in DKV (F(4,26) = 28.09, p < 0.001). However, relationships between other variables and DKV were not found. Conclusion: The core stability index and plantar arch index were associated with observed DKV during the single-leg squat. These results suggested that proximal and distal variables to the knee should be considered when evaluating individuals who present DKV during the single-leg squat. (C) 2021 Elsevier Ltd. All rights reserved

Study of the Effect and Persistence of Neuromuscular Exercises on Activity Timing of Lower Extremity Distal and Proximal Muscles in Athletes with Functional Ankle Instability

سابقه و هدف: اثر و ماندگاري اثر تمرينات عصبي- عضلاني بر زمان‌بندي فعاليت عضلات پروگزيمال اندام تحتاني مورد سوال است. لذا هدف از تحقيق حاضر بررسي اثر و ماندگاري اثر تمرينات عصبي- عضلاني بر زمان‌بندي فعاليت عضلات ديستال و پروگزيمال اندام تحتاني در ورزشکاران مبتلا به بي‌ثباتي عملکردي مچ پا بود. روش بررسي: تعداد 26 ورزشکار مبتلا به بي‌ثباتي عملکردي مچ پا بصورت تصادفي به دو گروه تمرينات عصبي- عضلاني و کنترل تقسيم شدند. انتخاب آزمودني‌ها بر اساس معيارهاي ورود و خروج از تحقيق بود. در مرحله پيش‌آزمون زمان‌بندي فعاليت عضلاني آزمودني‌ها بوسيله دستگاه الکتروميوگرافي سطحي مورد ارزيابي قرار گرفت. پس از آن گروه تمريني به مدت 6 هفته تمرينات مربوط به خود را انجام دادند. تمرينات 3 جلسه در هفته و هر جلسه تمريني به مدت 15 الي 20 دقيقه برگزار شد. سپس کليه اندازه‌گيري‌هاي مرحله پيش‌آزمون در مرحله پس‌آزمون و آزمون ماندگاري نيز به انجام رسيد. از روش‌هاي آماري تحليل واريانس ترکيبي با اندازه‌هاي تکراري و آزمون تعقيبي بونفروني جهت انجام تجزيه و تحليل‌هاي آماري استفاده شد. سطح معني‌داري کوچکتر از 05/0 در نظر گرفته شد. يافته‌ها: نتايج آزمون تحليل واريانس ترکيبي براي مقايسه نتايج بين‌ دو گروه در مورد زمان‌بندي فعاليت عضلات نشان از اثر تعاملي زمان(پيش‌آزمون‌پس‌آزمون‌ماندگاري) بر گروه (عصبي‌عضلاني و کنترل) در عضلات تيبياليس انتريور، پرونئوس لانگوس و گاستروکنميوس خارجي در گروه عصبي‌عضلاني شده است(P≤0/05). اما تفاوتي در زمان‌بندي فعاليت عضلات رکتوس فموريس، گلوتئوس مديوس و گلوتئوس ماکزيموس هيچ‌يک از دو گروه‌ در دو مرحله پس‌آزمون و ماندگاري نسبت به پيش‌آزمون مشاهده نشد (05/0&lt;P). نتيجه‌گيري: اگرچه تمرينات عصبي-عضلاني موجب بهبود زمان‌بندي فعاليت عضلات ديستال و ماندگاري آن شده است، اما اين بهبود در مورد عضلات پروگزيمال که نقش مهمي در زنجيره حرکتي اندام تحتاني دارند، صدق نمي‌کند. لذا پيشنهاد مي‌شود در توانبخشي عارضه بي‌ثباتي عملکردي مچ پا، از تمريناتي استفاده شود که علاوه بر تاثير بر بخش‌هاي ديستال، عضلات پروگزيمال را نيز مورد توجه قرار داده تا ريسک بروز آسيب مجدد کاهش يابد. How to cite this article: Kalantariyan M, Minoonejad H, Rajabi R, Seydi F. Study of the Effect and Persistence of Neuromuscular Exercises on Activity Timing of Lower Extremity Distal and Proximal Muscles in Athletes with Functional Ankle Instability. J Saf Promot Inj Prev. 2020; 8(2):75-85.Background and Objectives: The effect and persistence of neuromuscular activities on the timing of lower extremity proximal muscles are questionable. So the purpose of this study was to investigate the persistence effect of neuromuscular exercise on activity timing of lower extremity distal and proximal muscles in athletes with functional ankle instability. Materials and Methods: 26 athletes with functional ankle instability were randomly divided into two groups of neuromuscular exercises and control. Subjects were selected based on inclusion and exclusion criteria. In the pretest phase, the activity timing of muscles was evaluated with surface electromyography. The next step was to exercise group performing their own exercises for 6 weeks. Exercises were performed 3 sessions per week and each exercise session lasted 15 to 20 minutes. Then all pre-test measurements were performed in the post-test and persistence test. Repeated analysis using ANOVA and Bonferroni post hoc tests were used for statistical analysis. The significance level was considered less than 0.05. Results: Results of Mixed-ANOVA showed the interactive effect of time(pretest-posttest-persistence) on the group(neuromuscular-control) significantly changes the activity timing of distal muscles in the neuromuscular group(P≤0/05). But there was no difference in the activity timing of proximal muscles in either of two groups in post-test and persistence compared to pre-test(P≥0/05). Conclusion: Although neuromuscular exercises improves the activity timing of distal muscles and persistence, this improvement does not apply to proximal muscles that play an important role in the lower extremity chain. Therefore, it is suggested that in the rehabilitation of functional ankle instability, use exercises that, in addition to affecting the distal segments, also focus on the proximal muscles to reduce the risk of re-injury. How to cite this article: Kalantariyan M, Minoonejad H, Rajabi R, Seydi F. Study of the Effect and Persistence of Neuromuscular Exercises on Activity Timing of Lower Extremity Distal and Proximal Muscles in Athletes with Functional Ankle Instability. J Saf Promot Inj Prev. 2020; 8(2):75-85

Association between Preparatory Knee Muscle Activation and Knee Valgus Angle during Single Leg Cross Drop Landing Following Anterior Cruciate Ligament Reconstruction

Background: Knee valgus angle seems to be a key factor in both primary– and second–ACL injury risk models. The control of the alignment of the lower limb during dynamic movements depends on the neural activation of the muscles crossing the knee joint prior to the occurrence of stressful events. The current study examined the relationship between the preparatory knee muscle activity and knee valgus angle. Methods: Twenty-eight ACL reconstructed (ACLR) athletes were asked to perform three trials of a single-leg cross drop landing (SCD). Lower extremity kinematics and surface EMG were recorded. Initial contact knee valgus angle and EMG from 100 ms prior to ground contact were used in the data analyses. Results: Preparatory activation medial and lateral hamstring muscles were found to be negatively correlated with knee valgus angle at initial contact (P<0.05). However, the preparatory activity of vastus medialis and vastus lateralis muscles was not associated with initial contact knee valgus angle (P>0.05). Conclusion: The preparatory activity of the knee muscles is linked to knee valgus angle at initial contact, and it may indicate a potential target of second ACL injury prevention programs

Electromyography of scapular stabilizers in people without scapular dyskinesis during push-ups

Background: Push-up (PU) is widely considered an effective exercise to stabilize the scapular, especially if performed on unstable surfaces. However, available studies cover a wide range of exercise variations and differ according to exercise prescription, muscle selection and study design. Therefore, findings are contradictory, and conclusions for a proper application of the PU are difficult to draw. Objective: To synthesize the available literature on the changes in the activity of the periscapular muscles in individuals without scapular dyskinesis while performing different types of PU on unstable surfaces. Search procedure: Four online databases were searched from the earliest publications to 9 August 2023, using predefined keywords. Out of the 2,850 potential references identified in the primary search, 92 studies were reviewed in detail, of which 38 met the inclusion criteria and were included. Methodological quality was evaluated using a standardized form based on the Newcastle‒Ottawa scale for observational studies. Data combination was performed using CMA (v3), and the random-effects model was used to calculate the standardized mean difference (SMD) with a 95% confidence interval (CI). Results: The use of unstable surfaces in people without scapular dyskinesis led to increased activity of the upper trapezius during the PU (p = 0.017; I2 = 84.95%; SMD = 0.425 [95% CI 0.077, 0.773]) and knee PU (p = 0.023; I2 = 70.23%; SMD = 0.474 [95% CI 0.066, 0.882]) exercises and increased activity of the middle trapezius (MT) (p = 0.003; I2 = 64.50%; SMD = 0.672 [95% CI 0.225, 1.119]) and serratus anterior (SA) (p = 0.039; I2 = 4.25%; SMD = 0.216 [95% CI 0.011, 0.420]) muscles during the push-up plus (PUP) exercise. Conclusion: Using an unstable support base during PU does not necessarily increase the activity of all scapular stabilizers. The amount of muscle activity depends on the type of PU other than the type of support base. If an unstable surface is used, PUP exercise appears to be the most effective modality to increase the quality of training, improve performance, and prevent the occurrence of scapular dyskinesis due to the increase in the activity of the MT and SA muscles

Factors Associated With Lower Limb Injuries in Recreational Runners:A Cross-Sectional Survey Including Mental Aspects and Sleep Quality

Knowledge about prevalence and etiology of running-related injuries (RRIs) is important to design effective RRI prevention programs. Mental aspects and sleep quality seem to be important potential risk factors, yet their association with RRIs needs to be elucidated. The aims of this study are to investigate the epidemiology of RRIs in recreational runners and the association of mental aspects, sleep, and other potential factors with RRIs. An internet-based questionnaire was sent to recreational runners recruited through social media, asking for personal and training characteristics, mental aspects (obsessive passion, motivation to exercise), sleep quality, perceived health, quality of life, foot arch type, and RRIs over the past six months. Data were analyzed descriptively and using logistic regression. Self-reported data from 804 questionnaires were analyzed. Twenty-five potential risk factors for RRIs were investigated. 54% of runners reported at least one RRI. The knee was the most-affected location (45%), followed by the lower leg (19%). Patellofemoral pain syndrome was the most-reported injury (20%), followed by medial tibial stress syndrome (17%). Obsessive passionate attitude (odds ratio (OR):1.35; 95% confidence interval (CI):1.18-1.54), motivation to exercise (OR:1.09; CI:1.03-1.15), and sleep quality (OR:1.23; CI:1.15-1.31) were associated with RRIs, as were perceived health (OR:0.96; CI:0.94-0.97), running over 20 km/week (OR:1.58; CI:1.04-2.42), overweight (OR:2.17; CI:1.41-3.34), pes planus (OR:1.80; CI:1.12-2.88), hard-surface running (OR:1.37; CI:1.17-1.59), running company (OR:1.65; CI:1.16-2.35), and following a training program (OR:1.51; CI:1.09-2.10). These factors together explained 30% of the variance in RRIs. A separate regression analysis showed that mental aspects and sleep quality explain 15% of the variance in RRIs. The association of mental aspects and sleep quality with RRIs adds new insights into the multifactorial etiology of RRIs. We therefore recommend that besides common risk factors for RRI, mental aspects and sleep be incorporated into the advice on prevention and management of RRIs

Effects of Kinesthetic Imagery, Active and Combined Exercises on the Electromyographic Pattern of Hip Hyperextension and Tests of Relation with Lumbar Hyperlordosis

Abstract: Background: Mental exercise uses the same neuronal pathways involved in physical exercise to modify the pattern and function without the stress caused by physical exercise. This study investigated the effects of the three methods of kinesthetic imagery, active, and combined exercise (imagery and active) on the pattern of hip hyperextension and the strength of selected muscle of lumbo-pelvic in women with lumbar hyperlordosis. Method: In this semi-experimental study, 36 women with lumbar hyperlordosis (age: 34.47±3.79, height: 160.48±12.63, weight: 64.46±18.26) were sorted into three groups. The groups practiced three sessions per week for six weeks. The degree of lumbar lordosis using flexible ruler, electromyographic activity of the lumbo-pelvic muscles during hip hyperextension in the prone position using surface electromyogram, the strength of the gluteus maximus during hip hyperextention using dynamometer, the strength of abdominal muscles during lowering two legs test using goniometer, flexibility of hip flexor muscles during the Thomas test using goniometer, and flexibility of erector spine muscles during the Schober test using a meter were measured before and after the intervention. The Shapiro-Wilk test was used for normality of data, and the repeated measures variance test was used for the statistical analysis of data at a significance level of 0.05. Results: The results showed a significant difference between the three methods of kinesthetic imagery, active and combined (p -value = 0.001). There was a significant difference between the method of imagery exercise and the methods of active and combined exercise, but no significant difference was observed between the methods of active and combined exercise. Conclusion: Imagery exercises were effective in modifying the electromyographic activity of some lumbo-pelvic muscles (gluteus maximus and rectus femoris muscles); however, they did not have a significant effect on the strength, flexibility, or degree of lumbar lordosis. Combined exercise was as effective as active exercise in modifying the electromyographic activity of the lumbo-pelvic muscles, the strength of the abdominal and gluteus maximus muscles, and the flexibility of erector spine and hip flexor muscles

Prediction of Scapular Dyskinesis Through Electromyographic Indices of Scapulothoracic Muscles in Female Overhead Athletes

Background: Shoulder joint function and the athletic performance of overhead athletes are influenced by scapular dyskinesis (SD) due to its high prevalence among these athletes and the motor interaction between the scapula and the arm. The present study investigated the prediction of SD through the electromyographic indices of scapulothoracic muscles in female overhead athletes. Methods: The present descriptive-correlational study was carried out on 60 female volleyball, handball, basketball, and badminton athletes. The lateral scapular slide test was used to examine their SD. The required electromyography and electrogoniometry data was recorded simultaneously to measure the activity and onset time of scapulothoracic muscles, including upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA). The collected data was analyzed using Spearman correlation and multiple regression tests. Results: Significant correlations were found between all electromyographic variables and SD (P<0.01). The regression effects of all predictive variables on SD were significant (P=0.001). In terms of predictive power, UT/SA co-contraction (β=0.765), UT/LT co-contraction (β=0.716), LT onset time (β=0.672), LT activity (β=0.612), and SA onset time (β=0.576) had the highest regression effects on SD, respectively. The analysis of the study model showed that there was a strong correlation (r=0.694) between the predictive variables and SD and that the independent variables predicted 48% of the variance. Conclusion: The presence of imbalance in the scapulothoracic muscles of overhead athletes with SD indicates that athletes should be monitored by coaches, physiotherapists, and physicians for SD screening. It is also necessary to carry out prospective studies to examine and explore other variables related to SD