Search Results

You are looking at 1 - 10 of 681 items for :

  • "isometric" x
Clear All
Restricted access

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.

Restricted access

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

Restricted access

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

Restricted access

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

Restricted access

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

Restricted access

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

Restricted access

David Phillips and Andrew Karduna

joint angle, 2 muscle fiber properties, 3 and the particular muscle under investigation. 4 Reliability of EMG variables and measured isometric force has been demonstrated in a multitude of muscles, such as the quadriceps 5 and triceps brachii. 6 Establishing an EMG amplitude and isometric force

Restricted access

Claire J. Brady, Andrew J. Harrison, Eamonn P. Flanagan, G. Gregory Haff and Thomas M. Comyns

Isometric tests such as the isometric midthigh pull (IMTP) and isometric squat (ISqT) allow the assessment of athletes’ strength qualities from a force–time curve and are used to assess skeletal muscle function. 1 , 2 Buckner et al 3 suggested that typical strength assessments such as 1

Restricted access

Thomas Dos’Santos, Paul A. Jones, Jonathan Kelly, John J. McMahon, Paul Comfort and Christopher Thomas

Skeletal-muscle function can be evaluated using force-time curves generated during dynamic and isometric activities. Peak force (PF) and peak rate of force development (RFD) are commonly assessed 1 – 5 and have been reported to relate to various athletic performance tasks including baseball

Restricted access

Amy R. Lewis, William S.P. Robertson, Elissa J. Phillips, Paul N. Grimshaw and Marc Portus

. 37 , 38 No literature currently presents recommended values of maximal isometric force-generating capacity for use in computational modeling of elite wheelchair racing athletes. The aim of this research was 2-fold: (1) to assess the sensitivity of a musculoskeletal model to the defined value of