scholarly journals Changes in the Range of Motion of the Hip Joint and the Muscle Activity of the Rectus Femoris and Biceps Femoris of Stroke Patients during Obstacles Crossing on the Ground and Underwater

2014 ◽  
Vol 26 (8) ◽  
pp. 1143-1146 ◽  
Author(s):  
Myung-chul Kim ◽  
Seul-ki Han ◽  
Seung-kyun Kim
Keyword(s):  
Range Of Motion ◽  
Hip Joint ◽  
Muscle Activity ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Stroke Patients

Lower-Extremity Muscle Activity During Aquatic and Land Treadmill Running at the Same Speeds

2014 ◽  
Vol 23 (2) ◽  
pp. 107-122 ◽  
Author(s):  
W. Matthew Silvers ◽  
Eadric Bressel ◽  
D. Clark Dickin ◽  
Garry Killgore ◽  
Dennis G. Dolny
Keyword(s):  
Lower Extremity ◽  
Outcome Measures ◽  
Muscle Activity ◽  
Tibialis Anterior ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Swing Phase ◽  
Treadmill Running ◽  
Vastus Medialis ◽  
Lower Extremity Muscle

Context:Muscle activation during aquatic treadmill (ATM) running has not been examined, despite similar investigations for other modes of aquatic locomotion and increased interest in ATM running.Objectives:The objectives of this study were to compare normalized (percentage of maximal voluntary contraction; %MVC), absolute duration (aDUR), and total (tACT) lower-extremity muscle activity during land treadmill (TM) and ATM running at the same speeds.Design:Exploratory, quasi-experimental, crossover design.Setting:Athletic training facility.Participants:12 healthy recreational runners (age = 25.8 ± 5 y, height = 178.4 ± 8.2 cm, mass = 71.5 ± 11.5 kg, running experience = 8.2 ± 5.3 y) volunteered for participation.Intervention:All participants performed TM and ATM running at 174.4, 201.2, and 228.0 m/min while surface electromyographic data were collected from the vastus medialis, rectus femoris, gastrocnemius, tibialis anterior, and biceps femoris.Main Outcome Measures:For each muscle, a 2 × 3 repeated-measures ANOVA was used to analyze the main effects and environment–speed interaction (P ≤ .05) of each dependent variable: %MVC, aDUR, and tACT.Results:Compared with TM, ATM elicited significantly reduced %MVC (−44.0%) but increased aDUR (+213.1%) and tACT (+41.9%) in the vastus medialis, increased %MVC (+48.7%) and aDUR (+128.1%) in the rectus femoris during swing phase, reduced %MVC (−26.9%) and tACT (−40.1%) in the gastrocnemius, increased aDUR (+33.1%) and tACT (+35.7%) in the tibialis anterior, and increased aDUR (+41.3%) and tACT (+29.2%) in the biceps femoris. At faster running speeds, there were significant increases in tibialis anterior %MVC (+8.6−15.2%) and tACT (+12.7−17.0%) and rectus femoris %MVC (12.1−26.6%; swing phase).Conclusion:No significant environment–speed interaction effects suggested that observed muscle-activity differences between ATM and TM were due to environmental variation, ie, buoyancy (presumed to decrease %MVC) and drag forces (presumed to increase aDUR and tACT) in the water.

scholarly journals Kinematic and EMG Comparison Between Variations of Unilateral Squats Under Different Stabilities

2020 ◽  
Vol 4 (02) ◽  
pp. E59-E66
Author(s):  
Roland van den Tillaar ◽  
Stian Larsen
Keyword(s):  
Muscle Activity ◽  
Rectus Femoris ◽  
Gluteus Medius ◽  
Biceps Femoris ◽  
Peak Force ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Training Experience ◽  
Free Weight ◽  
Weight Condition

AbstractThe purpose of the study was to compare kinematics and muscle activity between two variations of unilateral squats under different stability conditions. Twelve male volunteers (age: 23±5 years, mass: 80±17 kg, height: 1.81±0.11 m, strength-training experience: 4.3±1.9 years) performed four repetitions with the same external load (≈4RM). Two variations (with the non-stance leg forwards vs. backwards) were performed in a Smith-machine and free-weight condition. The variables were barbell velocity, lifting time and surface electromyography activity of the lower extremity and trunk muscles during the descending and ascending phase. The main findings were 1) peak force was higher when performing the unilateral squats in the Smith machine; 2) peak ascending barbell velocity increased from repetition 3–4 with free weight; and 3) muscle activity from the rectus femoris, vastus lateral, biceps femoris, gluteus medius, and erector spinae increased with repetitions, whereas gluteus, and medial vastus and shank muscles were affected by the conditions. It was concluded that more peak force could be produced because of increased stability. However, peak barbell velocity increased from repetition to repetition in free-weight unilateral squats, which was probably because the participants grew more comfortable. Furthermore, increased instability causes more gluteus and vastus medial activation and foot variations mainly affected the calf muscles.

scholarly journals Characterization of kinesiological patterns of the frontal kick, mae-geri, in karate experts and non-karate practitioners

2014 ◽  
Vol 9 (1) ◽  
pp. 20 ◽  
Author(s):  
António M. VencesBrito ◽  
Marco A. Colaço Branco ◽  
Renato M. Cordeiro Fernandes ◽  
Mário A. Rodrigues Ferreira ◽  
Orlando J. S. M. Fernandes ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Vastus Lateralis ◽  
Plantar Flexion ◽  
Neuromuscular Control ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Knee Extension ◽  
Maximum Speed ◽  
Ballistic Performance ◽  
The Impact

Presently, coaches and researchers need to have a better comprehension of the kinesiological parameters that should be an important tool to support teaching methodologies and to improve skills performance in sports. The aim of this study was to (i) identify the kinematic and neuromuscular control patterns of the front kick (<em>mae-geri</em>) to a fixed target performed by 14 experienced karate practitioners, and (ii) compare it with the execution of 16 participants without any karate experience, allowing the use of those references in the analysis of the training and learning process. Results showed that the kinematic and neuromuscular activity during the kick performance occurs within 600 ms. Muscle activity and kinematic analysis demonstrated a sequence of activation bracing a proximal-to-distal direction, with the muscles presenting two distinct periods of activity (1, 2), where the karateka group has a greater intensity of activation – root mean square (RMS) and electromyography (EMG) peak – in the first period on <em>Rectus Femoris</em> (RF1) and  <em>Vastus Lateralis</em> (VL1) and a lower duration of co-contraction in both periods on <em>Rectus Femoris</em>-<em>Biceps Femoris</em> and <em>Vastus Lateralis</em>-<em>Biceps Femoris</em> (RF-BF; VL-BF). In the skill performance, the hip flexion, the knee extension and the ankle plantar flexion movements were executed with smaller difference in the range of action (ROA) in the karateka group, reflecting different positions of the segments. In conclusion, it was observed a general kinesiological pattern, which was similar in karateka and non-karateka practitioners. However, in the karateka group, the training induces a specialization in the muscle activity reflected in EMG and kinematic data, which leads to a better ballistic performance in the execution of the <em>mae-geri</em> kick, associated with a maximum speed of the distal segments, reached closer to the impact moment, possibly representing more power in the contact.

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.

The Effect of Foam Rolling Versus IASTM on Knee Range of Motion, Fascial Displacement, and Patient Satisfaction

2020 ◽  
pp. 1-8
Author(s):  
Michelle A. Sandrey ◽  
Cody Lancellotti ◽  
Cory Hester
Keyword(s):  
Patient Satisfaction ◽  
Soft Tissue ◽  
Range Of Motion ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Knee Extension ◽  
Iliotibial Band ◽  
Controlled Clinical Trial ◽  
Foam Rolling ◽  
Myofascial Release

Context: Soft tissue restrictions have been linked to poor flexibility and decreased range of motion (ROM). To decrease the soft tissue restrictions and ultimately increase ROM/flexibility, myofascial release techniques, such as foam rolling (FR) and instrument-assisted soft tissue mobilization (IASTM), have been used. However, the benefit regarding which technique is more beneficial remains unknown. Objective: To examine the effects of myofascial release techniques (FR vs the instrumented portion of IASTM) on knee joint ROM, rectus femoris (RF) and biceps femoris (BF) fascial displacement, and patient satisfaction. Design: Randomized controlled clinical trial. Setting: Mid-Atlantic University. Participants: Twenty moderately active participants (age 21.1 [2.0] y) with variable levels of soft tissue restriction in the quadriceps and hamstrings started and completed the study. Participants were randomly assigned to 2 groups, FR or IASTM. Interventions: All participants completed the same warm-up prior to the intervention. The FR group followed the proper FR protocol for gluteals/iliotibial band, quadriceps, and hamstrings/adductors, and the participants were monitored while the protocol was completed. The IASTM group received treatment on the gluteals/iliotibial band followed by the quadriceps, adductors, and hamstrings. Participants in both groups attended intervention sessions twice per week for 3 weeks. Prior to the start, knee ROM measurements were taken, along with fascial displacement measured via ultrasound. Upon completion of the study, posttest measurements were completed. A patient satisfaction survey was also administered at this time. Main Outcome Measures: Pretest to posttest knee ROM measurements, RF and BF fascial displacement, and patient satisfaction. Results: Both groups improved pretest to posttest for knee-extension ROM, with a slight trend toward increased knee-extension ROM for the FR group. Both groups improved pretest to posttest for BF and RF fascial displacement, in favor of the IASTM group for BF fascial displacement. Both groups were equally satisfied. Conclusions: As both groups improved pretest to posttest, either treatment could be used.

scholarly journals Lower Extremity Muscle Activity During a Women's Overhand Lacrosse Shot

2014 ◽  
Vol 41 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Brianna M. Millard ◽  
John A. Mercer
Keyword(s):  
Lower Extremity ◽  
Muscle Activity ◽  
Body Height ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Medial Gastrocnemius ◽  
Discrete Events ◽  
Warm Up ◽  
Lower Extremity Muscle ◽  
One Year

AbstractThe purpose of this study was to describe lower extremity muscle activity during the lacrosse shot. Participants (n=5 females, age 22±2 years, body height 162.6±15.2 cm, body mass 63.7±23.6 kg) were free from injury and had at least one year of lacrosse experience. The lead leg was instrumented with electromyography (EMG) leads to measure muscle activity of the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (GA). Participants completed five trials of a warm-up speed shot (Slow) and a game speed shot (Fast). Video analysis was used to identify the discrete events defining specific movement phases. Full-wave rectified data were averaged per muscle per phase (Crank Back Minor, Crank Back Major, Stick Acceleration, Stick Deceleration). Average EMG per muscle was analyzed using a 4 (Phase) x 2 (Speed) ANOVA. BF was greater during Fast vs. Slow for all phases (p<0.05), while TA was not influenced by either Phase or Speed (p>0.05). RF and GA were each influenced by the interaction of Phase and Speed (p<0.05) with GA being greater during Fast vs. Slow shots during all phases and RF greater during Crank Back Minor and Major as well as Stick Deceleration (p<0.05) but only tended to be greater during Stick Acceleration (p=0.076) for Fast vs. Slow. The greater muscle activity (BF, RF, GA) during Fast vs. Slow shots may have been related to a faster approach speed and/or need to create a stiff lower extremity to allow for faster upper extremity movements.

scholarly journals Single-Leg Squat Delicacies—The Position of the Nonstance Limb is an Important Consideration

2019 ◽  
Vol 28 (4) ◽  
pp. 318-324
Author(s):  
Benita Olivier ◽  
Samantha-Lynn Quinn ◽  
Natalie Benjamin ◽  
Andrew Craig Green ◽  
Jessica Chiu ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Repeated Measures ◽  
Inertial Sensors ◽  
Center Of Mass ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Trunk Flexion ◽  
Repeated Measures Design ◽  
Mass Displacement ◽  
Single Leg Squat

Context: The single-leg squat task is often used as a rehabilitative exercise or as a screening tool for the functional movement of the lower limb. Objective: To establish the effect of 3 different positions of the nonstance leg on 3-dimensional kinematics, muscle activity, and center of mass displacement during a single-leg squat. Design: Within-subjects, repeated-measures design. Setting: Movement analysis laboratory. Participants: A total of 10 participants, aged 28.2 (4.42) years performed 3 squats to 60° of knee flexion with the nonstance (1) hip at 90° flexion and knee at 90° flexion, (2) hip at 30° flexion with the knee fully extended, or (3) hip in neutral/0° and the knee flexed to 90°. Main Outcome Measures: Trunk, hip, knee and ankle joint angles, and center of mass displacement were recorded with inertial sensors while muscle activity was captured through wireless electromyography. Results: Most trunk flexion (21.38° [18.43°]) occurred with the nonstance hip at 90° and most flexion of the stance hip (23.10° [6.60°]) occurred with the nonstance hip at 0°. Biceps femoris activity in the 90° squat was 40% more than in the 0° squat, whereas rectus femoris activity in the 0° squat was 29% more than in the 90° squat. Conclusion: The position of the nonstance limb should be standardized when the single-leg squat is used for assessment and be adapted to the aim when used in rehabilitation.

scholarly journals Leg Muscle Activity and Perception of Effort before and after Four Short Sessions of Submaximal Eccentric Cycling

2020 ◽  
Vol 17 (21) ◽  
pp. 7702
Author(s):  
Pierre Clos ◽  
Romuald Lepers
Keyword(s):  
Muscle Activity ◽  
Peak Power ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Peak Power Output ◽  
Leg Muscles ◽  
Perception Of Effort ◽  
Before And After ◽  
Power Outputs

Background: This study tested muscle activity (EMG) and perception of effort in eccentric (ECC) and concentric (CON) cycling before and after four sessions of both. Methods: Twelve volunteers naïve to ECC cycling attended the laboratory six times. On day 1, they performed a CON cycling peak power output (PPO) test. They then carried-out four sessions comprising two sets of 1 to 1.5-min cycling bouts at 5 intensities (30, 45, 60, 75, and 90% PPO) in ECC and CON cycling. On day 2 and day 6 (two weeks apart), EMG root mean square of the vastus lateralis (VL), rectus femoris (RF), biceps femoris (BF), and soleus (SOL) muscles, was averaged from 15 to 30 s within each 1-min bout and perception of effort was asked after 45 s. Results: Before the four cycling sessions, while VL EMG was lower in ECC than CON cycling, most variables were not different. Afterwards, ECC cycling exhibited lower RF EMG at 75 and 90% PPO (all p < 0.02), lower VL and BF EMG at all exercise intensities (all p < 0.02), and inferior SOL EMG (all p < 0.04) except at 45% PPO (p = 0.07). Perception of effort was lower in ECC cycling at all exercise intensities (all p < 0.03) but 60% PPO (p = 0.11). Conclusions: After four short sessions of ECC cycling, the activity of four leg muscles and perception of effort became lower in ECC than in CON cycling at most of five power outputs, while they were similar before.

scholarly journals Focusing on Increasing Velocity during Heavy Resistance Knee Flexion Exercise Boosts Hamstring Muscle Activity in Chronic Stroke Patients

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Jonas Vinstrup ◽  
Joaquin Calatayud ◽  
Markus D. Jakobsen ◽  
Emil Sundstrup ◽  
Lars L. Andersen
Keyword(s):  
Muscle Strength ◽  
Muscle Activity ◽  
High Speed ◽  
Vastus Lateralis ◽  
Biceps Femoris ◽  
Maximum Load ◽  
Chronic Stroke ◽  
Stroke Patients ◽  
Speed Condition ◽  
Contraction Speed

Background. Muscle strength is markedly reduced in stroke patients, which has negative implications for functional capacity and work ability. Different types of feedback during strength training exercises may alter neuromuscular activity and functional gains.Objective. To compare levels of muscle activity during conditions of blindfolding and intended high contraction speed with a normal condition of high-intensity knee flexions.Methods. Eighteen patients performed unilateral machine knee flexions with a 10-repetition maximum load. Surface electromyography (EMG) was recorded from the quadrics and hamstring muscles and normalized to maximal EMG (nEMG) of the nonparetic limb.Results. For the paretic leg, the speed condition showed higher values of muscle activity compared with the normal and blindfolded conditions for both biceps femoris and semitendinosus. Likewise, the speed condition showed higher co-contraction values compared with the normal and blindfolded conditions for the vastus lateralis. No differences were observed between exercise conditions for the nonparetic leg.Conclusion. Chronic stroke patients are capable of performing heavy resistance training with intended high speed of contraction. Focusing on speed during the concentric phase elicited higher levels of muscle activity of the hamstrings compared to normal and blindfolded conditions, which may have implications for regaining fast muscle strength in stroke survivors.

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