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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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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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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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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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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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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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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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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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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

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Danny Lum and Abdul Rashid Aziz

have included either only dynamic strength measurements of the upper body 4 – 8 or isometric strength using kayak-specific movement. 3 , 9 , 10 Interestingly, only one study has endeavored to investigate the relationship between measures obtained from lower-limb strength assessment with sprint kayak