Lack of Effect of Ankle Position During the Nordic Curl on Muscle Activity of the Biceps Femoris and Medial Gastrocnemius

2017 ◽  
Vol 26 (3) ◽  
pp. 202-207 ◽  
Author(s):  
Paul Comfort ◽  
Amy Regan ◽  
Lee Herrington ◽  
Chris Thomas ◽  
John McMahon ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Repeated Measures ◽  
Biceps Femoris ◽  
Medial Gastrocnemius ◽  
Maximum Voluntary Isometric Contraction ◽  
Hamstring Strain ◽  
Repeated Measures Design ◽  
Paired Samples ◽  
Significant Difference ◽  
Male College

Context:Regular performance (~2×/wk) of Nordic curls has been shown to increase hamstring strength and reduce the risk of hamstring strain injury, although no consensus on ankle position has been provided.Objective:To compare the effects of performing Nordic curls, with the ankle in a dorsiflexed (DF) or plantar-flexed (PF) position, on muscle activity of the biceps femoris (BF) and medial gastrocnemius (MG).Participants:15 male college athletes (age 22.6 ± 2.1 y, height 1.78 ± 0.06 m, body mass 88.75 ± 8.95 kg).Design:A repeated-measures design was used, with participants performing 2 sets of 3 repetitions of both variations of Nordic curls, while muscle activity was assessed via surface electromyography (EMG) of the BF and MG. Comparisons of muscle activity were made by examining the normalized EMG data as the percentage of their maximum voluntary isometric contraction.Results:Paired-samples t test revealed no significant difference in normalized muscle activity of the BF (124.5% ± 6.2% vs 128.1 ± 5.0%, P > .05, Cohen d = 0.64, power = .996) or MG (82.1% ± 3.9% vs 83.5 ± 4.8%, P > .05, Cohen d = 0.32, power = .947) during the Nordic curls in a PF or DF position, respectively.Conclusion:Ankle position does not influence muscle activity during the Nordic curl; however, performance of Nordic curls with the ankle in a DF position may be preferential, as this replicates the ankle position during terminal leg swing during running, which tends to be the point at which hamstring strains have been reported.

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.

Comparison of Hip- and Back-Muscle Activity and Pelvic Compensation in Healthy Subjects During 3 Different Prone Table Hip-Extension Exercises

2017 ◽  
Vol 26 (4) ◽  
pp. 216-222 ◽  
Author(s):  
In-cheol Jeon ◽  
Oh-yun Kwon ◽  
Jong-hyuck Weon ◽  
Ui-jae Hwang ◽  
Sung-hoon Jung
Keyword(s):  
Outcome Measures ◽  
Muscle Activity ◽  
Repeated Measures ◽  
Motion Tracking ◽  
Gluteus Maximus ◽  
Biceps Femoris ◽  
Erector Spinae ◽  
Repeated Measure ◽  
Significant Difference ◽  
Hip Extension

Context:Prone hip extension has been recommended for strengthening the back and hip muscles. Previous studies have investigated prone hip extension conducted with subjects on the floor in the prone position. However, no study has compared 3 different table hip-extension (THE) positions in terms of the activities of the back- and hip-joint muscles with lumbopelvic motion.Objective:To identify more effective exercises for strengthening the gluteus maximus (GM) by comparing 3 different exercises (THE alone, THE with the abdominal drawing-in maneuver [THEA], and THEA with chair support under the knee [THEAC]) based on electromyographic muscle activity and pelvic compensation.Design:Repeated-measure within-subject intervention.Setting:University research laboratory.Participants:16 healthy men.Main Outcome Measures:Surface electromyography (EMG) was used to obtain data on the GM, erector spinae (ES), multifidus, biceps femoris (BF), and semitendinosus (ST). Pelvic compensation was monitored using an electromagnetic motion-tracking device. Exertion during each exercise was recorded. Any significant difference in electromyographic muscle activity and pelvic motion among the 3 conditions (THE vs THEA vs THEAC) was assessed using a 1-way repeated-measures analysis of variance (ANOVA) with Bonferroni post hoc test.Results:The muscle activities recorded by EMG differed significantly among the 3 exercises (P < .01). GM activity was increased significantly during THEAC (P < .01). There was a significant difference in lumbopelvic kinematics in terms of anterior tilting (F = 19.49, P < .01) and rotation (F= 27.38, P < .01) among the 3 exercises.Conclusions:The THEAC exercise was the most effective for strengthening the GM without overactivity of the ES, BF, and ST muscles and lumbopelvic compensation compared with THE and THEA.

scholarly journals Evaluation of lower limb electromyographic activity when using unstable shoes for the first time: A pilot quasi control trial

2012 ◽  
Vol 37 (4) ◽  
pp. 275-281 ◽  
Author(s):  
Helen Branthwaite ◽  
Nachiappan Chockalingam ◽  
Anand Pandyan ◽  
Gaurav Khatri
Keyword(s):  
Muscle Activity ◽  
Repeated Measures ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Medial Gastrocnemius ◽  
Heel Strike ◽  
Electromyographic Activity ◽  
Temporal Parameters ◽  
Unstable Shoes ◽  
First Time

Background: Unstable shoes, which have recently become popular, claim to provide additional physiological and biomechanical advantages to people who wear them. Alterations in postural stability have been shown when using the shoe after training. However, the immediate effect on muscle activity when walking in unstable shoes for the first time has not been investigated. Objective: To evaluate muscle activity and temporal parameters of gait when wearing Masai Barefoot Technology shoes® for the first time compared to the subject’s own regular trainer shoes. Study Design: A pilot repeated-measures quasi control trial. Method: Electromyographic measurements of lower leg muscles (soleus, medial gastrocnemius, lateral gastrocnemius, tibialis anterior, peroneus longus, rectus femoris, biceps femoris and gluteus medius) were measured in 15 healthy participants using Masai Barefoot Technology shoes and trainer shoes over a 10-m walkway. Muscle activity of the third and sixth steps was used to study the difference in behaviour of the muscles under the two shoe conditions. Temporal parameters were captured with footswitches to highlight heel strike, heel lift and toe off. Paired samples t-test was completed to compare mean muscle activity for Masai Barefoot Technology and trainer shoes. Results: Indicated that the use of Masai Barefoot Technology shoes increased the intensity of the magnitude of muscle activity. While this increase in the activity was not significant across the subjects, there were inter-individual differences in muscle activity. This variance between the participants demonstrates that some subjects do alter muscle behaviour while wearing such shoes. Conclusion: A more rigorous and specific assessment is required when advising patients to purchase the Masai Barefoot Technology shoe. Not all subjects respond positively to using unstable shoes, and the point in time when muscle behaviour can change is variable. Clinical relevance Use of Masai Barefoot Technology shoe in patient management should be monitored closely as the individual muscle changes and the point in time when changes occur vary between subjects, and evaluation of how a subject responds is not yet clear.

scholarly journals Influence of the Amount of Instability on the Leg Muscle Activity During a Loaded Free Barbell Half-Squat

2020 ◽  
Vol 17 (21) ◽  
pp. 8046
Author(s):  
Bernat Buscà ◽  
Joan Aguilera-Castells ◽  
Jordi Arboix-Alió ◽  
Adrià Miró ◽  
Azahara Fort-Vanmeerhaeghe ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Repeated Measures ◽  
Perceived Exertion ◽  
Vastus Lateralis ◽  
Biceps Femoris ◽  
The Body ◽  
Stability Conditions ◽  
Vastus Medialis ◽  
Centre Of Mass ◽  
Repeated Measures Design

This study aimed to understand the acute responses on the muscular activity of primary movers during the execution of a half-squat under different unstable devices. Fourteen male and female high-standard track and field athletes were voluntarily recruited. A repeated measures design was used to establish the differences between muscle activity of the primary movers, the body centre of mass acceleration and the OMNI-Perceived Exertion Scale for Resistance Exercise (OMNI-Res) in a half-squat under four different stability conditions (floor, foam, BOSU-up and BOSU-down). A significant correlation was found between the highest performance limb muscle activity and body centre of mass acceleration for half-squat floor (r = 0.446, p = 0.003), foam (r = 0.322, p = 0.038), BOSU-up (r = 0.500, p = 0.001), and BOSU-down (r = 0.495, p = 0.001) exercises. For the exercise condition, the half-squat BOSU-up and BOSU-down significantly increased the muscle activity compared to half-squat floor (vastus medialis: p = 0.020, d = 0.56; vastus lateralis: p = 0.006, d = 0.75; biceps femoris: p = 0.000–0.006, d = 1.23–1.00) and half-squat foam (vastus medialis: p = 0.005–0.006, d = 0.60–1.00; vastus lateralis: p = 0.014, d = 0.67; biceps femoris: p = 0.002, d = 1.00) activities. This study contributes to improving the understanding of instability training, providing data about the acute muscular responses that an athlete experiences under varied stability conditions. The perturbation offered by the two BOSU conditions was revealed as the most demanding for the sample of athletes, followed by foam and floor executions.

The Effects of Receiver Placement on Probe Microphone, Performance, and Subjective Measures with Open Canal Hearing Instruments

2010 ◽  
Vol 21 (04) ◽  
pp. 249-266 ◽  
Author(s):  
Lynzee N. Alworth ◽  
Patrick N. Plyler ◽  
Monika Bertges Reber ◽  
Patti M. Johnstone
Keyword(s):  
Repeated Measures ◽  
Hearing Aid ◽  
Clinical Importance ◽  
Ease Of Use ◽  
Subjective Measures ◽  
Repeated Measures Design ◽  
Hearing Instruments ◽  
Data Collection And Analysis ◽  
Significant Difference ◽  
Occlusion Effect

Background: Open canal hearing instruments differ in method of sound delivery to the ear canal, distance between the microphone and the receiver, and physical size of the devices. Moreover, RITA (receiver in the aid) and RITE (receiver in the ear) hearing instruments may also differ in terms of retention and comfort as well as ease of use and care for certain individuals. What remains unclear, however, is if any or all of the abovementioned factors contribute to hearing aid outcome. Purpose: To determine the effect of receiver location on performance and/or preference of listeners using open canal hearing instruments. Research Design: An experimental study in which subjects were exposed to a repeated measures design. Study Sample: Twenty-five adult listeners with mild sloping to moderately severe sensorineural hearing loss (mean age 67 yr). Data Collection and Analysis: Participants completed two six-week trial periods for each device type. Probe microphone, objective, and subjective measures (quiet, noise) were conducted unaided and aided at the end of each trial period. Results: Occlusion effect results were not significantly different between the RITA and RITE instruments; however, frequency range was extended in the RITE instruments, resulting in significantly greater maximum gain for the RITE instruments than the RITA instruments at 4000 and 6000 Hz. Objective performance in quiet or in noise was unaffected by receiver location. Subjective measures revealed significantly greater satisfaction ratings for the RITE than for the RITA instruments. Similarly, preference in quiet and overall preference were significantly greater for the RITE than for the RITA instruments. Conclusions: Although no occlusion differences were noted between instruments, the RITE did demonstrate a significant difference in reserve gain before feedback at 4000 and 6000 Hz. Objectively; no positive benefit was noted between unaided and aided conditions on speech recognition tests. These results suggest that such testing may not be sensitive enough to determine aided benefit with open canal instruments. However, the subjective measures (Abbreviated Profile of Hearing Aid Benefit [APHAB] and subjective ratings) did indicate aided benefit for both instruments when compared to unaided. This further suggests the clinical importance of subjective measures as a way to measure aided benefit of open-fit devices.

scholarly journals Role of Occupational Footwear and Prolonged Walking on Lower Extremity Muscle Activation during Maximal Exertions and Postural Stability Tasks

Biomechanics ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 202-213
Author(s):  
Harish Chander ◽  
Sachini N. K. Kodithuwakku Arachchige ◽  
Alana J. Turner ◽  
Reuben F. Burch V ◽  
Adam C. Knight ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Muscle Activity ◽  
Repeated Measures ◽  
Postural Stability ◽  
Muscle Activation ◽  
Medial Gastrocnemius ◽  
Lower Extremity Muscle ◽  
Prolonged Duration ◽  
The Mean ◽  
The Impact

Background: Occupational footwear and a prolonged duration of walking have been previously reported to play a role in maintaining postural stability. The purpose of this paper was to analyze the impact of three types of occupational footwear: the steel-toed work boot (ST), the tactical work boot (TB), and the low-top work shoe (LT) on previously unreported lower extremity muscle activity during postural stability tasks. Methods: Electromyography (EMG) muscle activity was measured from four lower extremity muscles (vastus medialis (VM), medial hamstrings (MH), tibialis anterior (TA), and medial gastrocnemius (MG) during maximal voluntary isometric contractions (MVIC) and during a sensory organization test (SOT) every 30 min over a 4 h simulated workload while wearing ST, TB, and LT footwear. The mean MVIC and the mean and percentage MVIC during each SOT condition from each muscle was analyzed individually using a repeated measures ANOVA at an alpha level of 0.05. Results: Significant differences (p < 0.05) were found for maximal exertions, but this was limited to only the time main effect. No significant differences existed for EMG measures during the SOT. Conclusion: The findings suggest that occupational footwear type does not influence lower extremity muscle activity during both MVIC and SOT. Significantly lower muscle activity during maximal exertions over the course of the 4 h workload was evident, which can be attributed to localized muscular fatigue, but this was not sufficient to impact muscle activity during postural stability tasks.

Effect of Adaptive Compression and Fast-Acting WDRC Strategies on Sentence Recognition in Noise in Mandarin-Speaking Pediatric Hearing Aid Users

2018 ◽  
Vol 29 (04) ◽  
pp. 273-278
Author(s):  
Haihong Liu ◽  
Yuanhu Liu ◽  
Ying Li ◽  
Xin Jin ◽  
Jing Li ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Dynamic Range ◽  
Hearing Aid ◽  
Hearing Threshold ◽  
T Test ◽  
Sentence Recognition ◽  
Repeated Measures Design ◽  
Paired Samples ◽  
Adaptive Compression ◽  
Fast Acting

AbstractWide dynamic range compression (WDRC) has been widely used in hearing aid technology. However, several reports indicate that WDRC may improve audibility at the expense of speech intelligibility. As such, a modified amplification compression scheme, named adaptive compression, was developed. However, the effect of compression strategies on speech perception in pediatric hearing aid users has not been clearly reported.The purpose of the present study was to investigate the effect of adaptive compression and fast-acting WDRC processing strategies on sentence recognition in noise with Mandarin, pediatric hearing aid users.This study was set up using a double-blind, within-subject, repeated-measures design.Twenty-six children who spoke Mandarin Chinese as their primary language and had bilateral sensorineural hearing loss participated in the study.Sentence recognition in noise was evaluated in behind-the-ear technology with both adaptive compression processing and fast-acting WDRC processing and was selected randomly for each child. Percent correct sentence recognition in noise with fast-acting WDRC and adaptive compression was collected from each participant. Correlation analysis was performed to examine the effect of gender, age at assessment, and hearing threshold of the better ear on signal-to-noise ratio, and a paired-samples t test was employed to compare the performance of the adaptive compression strategy and fast-acting WDRC processing.The mean percentage correct of sentence recognition in noise with behind-the-ear technology with fast-acting WDRC and adaptive compression processing were 62.24% and 68.71%, respectively. The paired-samples t test showed that the performance of the adaptive compression strategy was significantly better than the fast-acting WDRC processing (t = 3.190, p = 0.004).Compared with the fast-acting WDRC, adaptive compression provided better sentence recognition in noise for Mandarin pediatric hearing aid users.

Difference of Hamstring Activity Between Bilateral and Unilateral Nordic Hamstring Exercises With a Sloped Platform

2021 ◽  
pp. 1-6
Author(s):  
Toshiaki Soga ◽  
Taspol Keerasomboon ◽  
Kei Akiyama ◽  
Norikazu Hirose
Keyword(s):  
High Speed ◽  
Biceps Femoris ◽  
Break Point ◽  
Hamstring Injury ◽  
Emg Activity ◽  
Maximum Voluntary Isometric Contraction ◽  
Mean Values ◽  
Significant Difference ◽  
Long Head ◽  
Control Study

Context: This study aimed to examine the differences in electromyographic (EMG) activity of the biceps femoris long head (BFlh) and semitendinosus (ST) muscles, break-point angle (BPA), and the angle at peak BFlh EMG activity between bilateral and unilateral Nordic hamstring exercise (NHE) on a sloped platform. Design: This study was designed as a case-control study. Methods: Fourteen men participated in the study. The participants initially performed maximum voluntary isometric contraction (MVIC) on the prone leg curl to normalize the peak hamstring EMG amplitude as the %MVIC. Then, participants were randomized to perform the following 3 variations of NHE: bilateral (N40) or unilateral (N40U) NHE with a platform angle of 40°, and unilateral NHE with a platform angle of 50° (N50U). The EMG activities of the BFlh and ST and the knee flexion angle during the NHE variations were recorded to calculate the EMG activity of the BFlh and ST in terms of the %MVIC, the angle at peak BFlh EMG, and BPA. Results: The BFlh %MVIC was significantly higher in N40U (P < .05) and N50U (P < .05) than in N40. A significant difference in BFlh %MVIC and ST %MVIC was observed between N40U (P < .05) and N50U (P < .05). The mean values of BPA and the angle at peak BFlh EMG were <30° for all NHE variations. Conclusions: In the late swing phase of high-speed running, BFlh showed higher EMG activity; thus, unilateral NHE may be a specific hamstring exercise for hamstring injury prevention.

scholarly journals Effect of acute antagonist static stretching on upper-body agonist power

2019 ◽  
Vol 15 (1) ◽  
pp. 53-59
Author(s):  
Dave Elliott ◽  
Dayne Massey
Keyword(s):  
Repeated Measures ◽  
Effective Means ◽  
Upper Body ◽  
Static Stretching ◽  
Repeated Measures Design ◽  
Significant Difference ◽  
Potential Benefits ◽  
Upper Body Power ◽  
The Impact ◽  
Practical Implications

There are many studies showing acute static stretching to be detrimental to power generation. However, the majority have focused upon the impact of stretching the agonist musculature. To date, few have examined the potential benefits of acute antagonist static stretching; none have focused on upper-body power. Utilising a repeated-measures design, 30 male participants were randomly assigned to one of two groups whereupon they performed four bench-throw tests; two control (NO-STRETCH) and two experimental (STRETCH), in a counter-balanced manner. Prior to the experimental measures, participants undertook a series of static antagonist stretches. Mean Pmax (SD) in the NO-STRETCH trials was 862.76 (146)W and 898.50 (144)W, respectively. For STRETCH trial 1, Pmax = 930.10 (146)W and trial 2, Pmax = 953.36 (136)W. When compared to the respective NO-STRETCH trials, antagonist static stretching did have a significant effect on Pmax for both the initial ( P < 0.01, d = 1.33) and the re-stretching procedures ( P < 0.01, d = 1.35). A significant difference was also found between the STRETCH trials ( P < 0.01, d = 0.46). The results have practical implications for those involved in upper-body power activities. Specifically, incorporating upper-body antagonist static stretching into pre-performance routines might offer a simple and effective means of enhancing agonist power.

Treatment of Objective and Subjective Benign Paroxysmal Positional Vertigo

2013 ◽  
Vol 24 (07) ◽  
pp. 600-606 ◽  
Author(s):  
Alexandra C. Huebner ◽  
Susan R. Lytle ◽  
Steven M. Doettl ◽  
Patrick N. Plyler ◽  
James T. Thelin
Keyword(s):  
Repeated Measures ◽  
Benign Paroxysmal Positional Vertigo ◽  
Head Position ◽  
Subjective Report ◽  
Repeated Measures Design ◽  
Positional Vertigo ◽  
Data Collection And Analysis ◽  
Significant Difference ◽  
Before And After ◽  
Paroxysmal Positional Vertigo

Background: Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo in adults and is a result of otolithic particles or debris that become free floating within a semicircular canal or adhere to the cupula. Characteristics of BPPV include brief episodes of latent onset vertigo that occur with changes in head position, transient rotary nystagmus beating toward the dependent ear, and reversed nystagmus upon sitting up. Both the vertigo and nystagmus fatigue quickly while maintaining the same head position. The BPPV may be classified as objective or subjective. Objective BPPV presents all the aforementioned symptoms whereas subjective BPPV presents all the symptoms without nystagmus. The accepted method of treatment for objective BPPV is canalith repositioning maneuvers (CRM); however, CRM are not traditionally used as the method of treatment for cases of subjective BPPV. Purpose: The purpose of the study was to determine if the subjective report of dizziness using the Dizziness Handicap Inventory (DHI) was different in patients with objective and subjective BPPV and to determine if the two groups showed similar improvements in perceived dizziness handicap following CRM treatment. Research Design: The present study utilized a retrospective, repeated measures design. Study Sample: Sixty-three adults with BPPV that were given the DHI both before and after CRM treatment. Data Collection and Analysis: Pre and post DHI results were analyzed for participants with objective versus subjective BPPV. A five-question DHI subscale was also analyzed between the groups. Results: A significant difference was noted between initial and posttreatment DHI scores for patients in both the subjective and objective groups when using the full-scale and subscale DHI. No significant difference was noted between groups for their initial or posttreatment DHI scores. The two groups also did not differ significantly in their initial or posttreatment DHI subscale scores. Conclusions: The results of the study indicated that individuals with both objective and subjective BPPV demonstrated significant improvement in DHI scores following CRM treatment. Additionally, there was no difference in DHI improvement for the subjective versus objective group suggesting CRM are effective for both subjective BPPV and objective BPPV. This improvement in DHI scores was also noted in the five-question DHI subscale with no significant difference noted between groups. These findings combined with previous studies suggest the presence or absence of nystagmus during Dix-Hallpike maneuvers is not related to the effectiveness of treatment using CRM.

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