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Surface Electromyography of the Internal and External Oblique Muscles During Isometric Tasks Targeting the Lateral Trunk

Allison L. Kinney, Matthew Giel, Brady Harre, Kyle Heffner, Timothy McCullough, Maria Savino, Alexi Scott, and Joaquin A. Barrios

the lateral trunk in an isometric effort, the lateral plank (LP) test position was originally advocated by McGill et al. 1 While positional hold times are reliable, the LP test often elicits upper-extremity pain or fatigue during testing. These issues can lead to unwanted test termination

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Longer Integration Intervals Reduce Variability and Improve Reliability of EMG Derived from Maximal Isometric Exertions

Peter F. Vint and Richard N. Hinrichs

Isometric knee extension force and average integrated EMG of the vastus lateralis muscle were obtained from 27 healthy subjects using a maximum effort, ramp and hold protocol. In each of the 125 total trials mat were included in the analysis, a 2-s plateau region was extracted and divided into two adjacent 1000-ms bins. Variability and reliability of bin-to-bin measurements of force and EMG were then evaluated across 14 different integration intervals ranging from 10 to 1000 ms. Statistical analyses of bin-to-bin variability measures demonstrated that integration intervals of 250 ms and longer significantly reduced variability and improved reliability of average integrated EMG values during maximum effort isometric exertions. Bin-to-bin EMG reliability increased from .728 at 10 ms to .991 at 1000 ms. Force parameters appeared less sensitive to changes in length of the integration interval. It was suggested that longer intervals might also improve the validity of the EMG-force relationship during maximum effort isometric exertions by reducing problems associated with electromechanical delay.

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Reliability and Validity of a Novel Trunk-Strength Assessment for High-Performance Sprint Flat-Water Kayakers

Darren Steeves, Leo J. Thornley, Joshua A. Goreham, Matthew J. Jordan, Scott C. Landry, and Jonathon R. Fowles

confers a long lever arm around which rotation can occur and against which muscles can be stabilized as they contract. 11 , 12 Trunk strength is important in athletic performance, and strong evidence exists linking isometric strength to dynamic sport-specific performance. 13 – 15 Blazevich 16 points to

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Poststretch Isometric Contractions of the Hamstrings: Just a Brief Stretch to Achieve Supramaximal Isometric Force

Neil Chapman, John William Whitting, Suzanne Broadbent, Zachary Crowley-McHattan, and Rudi Meir

eccentrically or are passively lengthened during the late swing phase of the gait cycle. 13 Accordingly, research into hamstring strain injuries includes both an eccentric and isometric contraction focus. In primary prevention of hamstring strain injuries, the alteration of intrinsic, modifiable risk factors

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Systematic, Unintended Drifts in the Cyclic Force Produced with the Fingertips

Satyajit Ambike, Daniela Mattos, Vladimir Zatsiorsky, and Mark Latash

, Vaillancourt, & Newell, 2000 ; Vaillancourt & Russell, 2002 ; Zhou, Solnik, Wu, & Latash, 2014 ). In particular, during accurate, constant force production tasks in isometric conditions with visual feedback, turning the feedback off results in a slow consistent drift of the force, typically to lower

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Effect of Sex and Level of Activity on Lower-Extremity Strength, Functional Performance, and Limb Symmetry

Caroline Lisee, Lindsay Slater, Jay Hertel, and Joe M. Hart

population-specific normative values of these tasks to help further improve the return-to-play decision process. Strength of the quadriceps and hamstring muscle groups are consistently tested through isokinetic and isometric tasks at varying speeds and joint positions. 4 , 12 , 13 Functional performance is

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Effects of Mental Fatigue on Physical Endurance Performance and Muscle Activation Are Attenuated by Monetary Incentives

Denver M.Y. Brown and Steven R. Bray

). In the exercise domain, studies have measured muscle activation (i.e., motor unit activation) while performing isometric muscle contractions ( Bray et al., 2008 ; Graham, Sonne, & Bray, 2014 ) and endurance cycling ( Pageaux, Marcora, Rozand, & Lepers, 2015 ). These studies have shown that

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Muscle- and Region-Specific Associations Between Muscle Size and Muscular Strength During Hip Extension and Knee Flexion in the Hamstrings

Raki Kawama, Masamichi Okudaira, Hirohiko Maemura, and Satoru Tanigawa

-extension and knee-flexion strength (in newton meters) were assessed during maximal voluntary isometric contraction (isometric MVC) and concentric contraction (concentric MVC) at angular velocities of 60°/s and 180°/s. After 5 to 7 days of the strength measurements, the ACSA (in centimeters squared) in the

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Concurrent Validity of Lower Limb Muscle Strength by Handheld Dynamometry in Children 7 to 11 Years Old

Ryan Mahaffey, Megan Le Warne, Stewart C. Morrison, Wendy I. Drechsler, and Nicola Theis

wore shorts and t-shirt and removed shoes and socks during data collection. HHD (Wagner Force One FDIX Force Gauge, Wagner) and ID (Cybex II, CSMI) were performed to determine isometric strength of the hip abductors, adductors, flexors and extensors, knee flexors and extensors, and ankle dorsiflexors

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Crossover Effects of Unilateral Static Stretching and Foam Rolling on Contralateral Hamstring Flexibility and Strength

Benjamin S. Killen, Krista L. Zelizney, and Xin Ye

investigation used a within-subjects randomized crossover design to examine the crossover effects of unilateral hamstring’s SS and SAFR on the contralateral hip-flexion passive ROM as well as the contralateral hamstring’s isometric strength and corresponding electromyographic (EMG) parameters. Three separate