Dataset Information

Mirror Electromyografic Activity in the Upper and Lower Extremity: A Comparison between Endurance Athletes and Non-Athletes.

ABSTRACT: During unimanual motor tasks, muscle activity may not be restricted to the contracting muscle, but rather occurs involuntarily in the contralateral resting limb, even in healthy individuals. This phenomenon has been referred to as mirror electromyographic activity (MEMG). To date, the physiological (non-pathological) form of MEMG has been observed predominately in upper extremities (UE), while remaining sparsely described in lower extremities (LE). Accordingly, evidence regarding the underlying mechanisms and modulation capability of MEMG, i.e., the extent of MEMG in dependency of exerted force during unilateral isometric contractions are insufficiently investigated in terms of LE. Furthermore, it still remains elusive if and how MEMG is affected by long-term exercise training. Here, we provide novel quantitative evidence for physiological MEMG in homologous muscles of LE (tibialis anterior (TA), rectus femoris (RF)) during submaximal unilateral dorsiflexion in healthy young adults. Furthermore, endurance athletes (EA, n = 11) show a higher extent of MEMG in LE compared to non-athletes (NA, n = 11) at high force demands (80% MVC, maximum voluntary contraction). While the underlying neurophysiological mechanisms of MEMG still remain elusive, our study indicates, at least indirectly, that sport-related long-term training might affect the amount of MEMG during strong isometric contractions specifically in trained limbs. To support this assumption of exercise-induced limb-specific MEMG modulation, future studies including different sports disciplines with contrasting movement patterns and parameters should additionally be performed.

SUBMITTER: Maudrich T

PROVIDER: S-EPMC5649197 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Mirror Electromyografic Activity in the Upper and Lower Extremity: A Comparison between Endurance Athletes and Non-Athletes.

Maudrich Tom T Kenville Rouven R Lepsien Jöran J Villringer Arno A Ragert Patrick P Steele Christopher J CJ

Frontiers in human neuroscience 20170929

During unimanual motor tasks, muscle activity may not be restricted to the contracting muscle, but rather occurs involuntarily in the contralateral resting limb, even in healthy individuals. This phenomenon has been referred to as mirror electromyographic activity (MEMG). To date, the physiological (non-pathological) form of MEMG has been observed predominately in upper extremities (UE), while remaining sparsely described in lower extremities (LE). Accordingly, evidence regarding the underlying ...[more]

PMID: 29085288

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Project description:BackgroundResearch indicates that mechanics differ between athletes with and without upper extremity pain; however, it is unclear which modifiable risk factors exist for throwing-related pain in softball athletes.PurposeTo determine whether sport specialization, throwing, practice, and strength and conditioning training volumes vary between youth softball athletes with and without upper extremity pain. It was hypothesized that youth softball athletes with upper extremity pain would participate in softball year-round and have greater throwing, practice, and strength and conditioning volumes compared with those without pain.Study designCross-sectional study; Level of evidence, 3.MethodsA total of 232 youth softball athletes from travel ball, middle school, and high school leagues were invited to complete a survey to assess pain, sport specialization, throwing, practice, and strength and conditioning training volumes. Participants were classified into upper extremity pain and no pain groups based on their survey answers. The responses were compared between groups using Mann-Whitney U and chi-square tests.ResultsA total of 101 athletes-with a mean ± SD age of 13.3 ± 2.3 years, height of 161 ± 13.4 cm, and weight of 59.8 ± 14.8 kg-completed the survey and were included for analysis. The response rate was 43.53%, with 22 athletes in the upper extremity pain group and 79 athletes in the no pain group. A significant difference was observed between hours devoted per week to off-season softball practice (U, 626.6; Z =-2; P = .045), where those without upper extremity pain spent 4 fewer median hours (6 hours) practicing softball per week in the off-season compared with those with pain (10 hours). Also, a significant difference was found between the number of throws during an in-season game (U, 457; Z, -2.28; P = .022), where those without upper extremity pain reported 21 fewer median throws (70 throws) during an in-season game compared with those with pain (91 throws). Furthermore, 77% of those who reported upper extremity pain continued to play despite their pain. There were no other significant differences between demographic characteristics, specialization, injury history, and primary position, as well as throwing, practice, and strength and conditioning volumes.ConclusionOur study demonstrates that youth softball athletes with upper extremity pain had more throws during in-season games and increased hours per week devoted to off-season practice than athletes without upper extremity pain. Our findings support the need for softball stakeholders (eg, coaches, clinicians, parents, and administrators) to engage in further research and recommendations regarding in-season pitch counts and off-season rest.

Project description:BACKGROUND:Yearly changes in active joint stiffness may help explain when neuromuscular sex differences emerge in adolescent athletes that may relate to increased anterior cruciate ligament injury risk in females. HYPOTHESIS:Pubertal males would demonstrate increases in knee stiffness while pubertal females would not. Second, postpubertal female athletes would have significantly lower knee joint stiffness than postpubertal male athletes. STUDY DESIGN:Cohort Study; Level of Evidence 2 and Cross-Sectional Study; Level of Evidence 3. METHODS:Two hundred sixty-five females and 50 males participated in 2 testing sessions approximately 1 year apart. The subjects were classified as either pubertal (n = 182, age 12.4 +/- 0.9 years) or postpubertal (n = 133, age 14.5 +/- 1.4 years) based on the modified Pubertal Maturational Observational Scale at each visit. Active joint stiffness of the ankle, knee, and hip was estimated during a drop vertical jump. Stiffness was calculated as the slope of the moment-angle curve from a least squares linear regression during the stance phase. RESULTS:All athletes showed increased active knee stiffness during the span of a year (P < 0.05). However, this increase was not different when stiffness was normalized to body mass. Only males demonstrated greater magnitudes of ankle and hip active stiffness (P < .05). Peak ankle and hip moments, but not knee moments, in postpubertal males were significantly greater than postpubertal females (P < .05). Females had a higher knee to hip moment ratio than males (P < .05). CONCLUSION:Both males and females showed increased active knee stiffness during the span of a year; males demonstrated increased ankle and hip active stiffness as well. Differences in hip joint posture at initial contact (greater flexion in males) and external hip flexion moment (greater flexion magnitude in males) may indicate that males use a different hip recruitment strategy during drop vertical jumps than females.

Dataset Information

Mirror Electromyografic Activity in the Upper and Lower Extremity: A Comparison between Endurance Athletes and Non-Athletes.

Publications

Mirror Electromyografic Activity in the Upper and Lower Extremity: A Comparison between Endurance Athletes and Non-Athletes.

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