Expression of the bilateral deficit during reflexively  evoked contractions

Khodiguian, Nazareth; Cornwell, Andrew; Lares, Eddie; DiCaprio, P. A.; Hawkins, Steve

doi:10.1152/japplphysiol.00703.2002

Cited by 32 publications

(28 citation statements)

References 42 publications

(56 reference statements)

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“…Although implicated, the assumption of 60% of baseline MVE as fatigue state prior to testing ensured that all participants were fatigued at similar levels. Previous studies on the difference between the strength in unilateral and bilateral exertions have produced equivocal results [28]. However, a study by Jacobi et al [29] concluded that the force production is not altered during bilateral contractions.…”

Section: Discussionmentioning

confidence: 97%

Effects of quadriceps fatigue on the biomechanics of gait and slip propensity

Parijat

Lockhart

2008

Gait & Posture

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This study examines how lower extremity fatigue of the quadriceps alters gait variables related to slip propensity. Sixteen healthy young adults were recruited to walk across vinyl floor surfaces in states of fatigue and no fatigue. Kinematic and kinetic data were collected using a three-dimensional motion analysis system and force plates. The results indicated a significant increase in both the heel contact velocity and required coefficient of friction and a decrease in the transitional acceleration of the whole body center of mass and peak knee joint moment in the fatigue trials. Thus, suggesting that slip propensity could increase with fatigue. Additionally, there was increased knee flexion and reduced ankle dorsiflexion at the heel contact phase of the gait cycle during fatigue trials. These findings provide new insights into the biomechanical relationship between localized muscle fatigue and gait parameters associated with slip propensity. The present study concluded that localized muscle fatigue affects gait parameters and hence can be considered as a potential risk factor for slipinduced falls.

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Section: Discussionmentioning

confidence: 97%

Effects of quadriceps fatigue on the biomechanics of gait and slip propensity

Parijat

Lockhart

2008

Gait & Posture

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“…There have been numerous studies providing evidence of bilateral deficit in both upper and lower limbs in a range of tasks. 1 Tasks that have been investigated include: single joint isometrics 3,4 single joint isokinetics, 5 multi-joint isometrics, 6,7 multi-joint isokinetic tasks, 3 reflexively evoked contractions 8 and dynamic skills such as jumping. [9][10][11] Generally the difference between the sum of the unilateral and the bilateral measures is around 10% when bilateral deficit is present, but the presence of bilateral deficit can be task and subject specific.…”

Section: Introductionmentioning

confidence: 99%

Considerations for Single and Double Leg Drop Jumps: Bilateral Deficit, Standardizing Drop Height, and Equalizing Training Load

Pain

2014

Journal of Applied Biomechanics

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Bilateral deficit is well documented; however, bilateral deficit is not present in all tasks and is more likely in dynamic activities than isometric activities. No definitive mechanism(s) for bilateral deficit is known but an oft cited mechanism is lower activation of fast twitch motor units. The aim of this study was to produce comparable and consistent one and two legged drop jumps to examine bilateral deficit in elite power athletes and elite endurance athletes. Seven power athletes and seven endurance athletes performed single and double leg drop jumps from a range of heights that equalized loading per leg in terms of: height dropped, energy absorbed, and momentum absorbed. Force and motion data were collected at 800 Hz. Bilateral deficit for jump height, peak concentric force, and peak concentric power were calculated. Power athletes had a significantly greater (P< .05) bilateral deficit for jump height and peak power, possibly due to power athletes having more fast twitch motor units, however, endurance athletes generally had a bilateral surfeit which could confound this inference. Results indicate that equalizing loading by impulse per leg is the most appropriate and that a consistent drop height can be obtained with a short 10 minute coaching session.

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“…Most of the studies performed on upper (Herbert and Gandevia 1996;McLean et al 2006;Post et al 2007) and lower (Howard and Enoka 1991;Jakobi and Cafarelli 1998;Khodiguian et al 2003) limbs have recorded strength with two separate strain gauges. Use of two strain gauges is a better way to evaluate the BL deficit, because it is possible to measure the force produced by each limb independently.…”

Section: Introductionmentioning

confidence: 99%

Comparison of maximal unilateral versus bilateral voluntary contraction force

2010

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The aim of the present study was to determine whether the difference in maximal voluntary contraction (MVC) forces between unilateral (UL) and bilateral (BL) contractions could be due to a difference in the timing of MVC peak force production between legs during BL MVC, or due to the maximal voluntary activation level (VAL) in each leg between UL and BL MVC. Thirteen active men (28 ± 6 years) volunteered to participate in an experimental session requiring the performance of MVC with right, left and both knee extensor muscles. An ergometer equipped with two strain gauges was used to assess the timing of MVC peak force production of each leg during BL MVC. Transcutaneous electrical stimulation was used to investigate VAL and electromyography (EMG) activity. The present results showed that the sum of the right and left UL MVC was higher compared to BL MVC force, i.e., a BL deficit of force. The timing of MVC peak force production of each leg during BL MVC was not different, but BL MVC force was lower than the sum of BL MVC(R) and BL MVC(L) force (i.e., maximal force production of each leg during BL MVC). No changes of EMG activity, M-wave amplitude, VAL, and peak doublet between UL and BL contractions were observed. The difference found in the production of force during BL MVC cannot be explained by the timing of force production of each leg.

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Expression of the bilateral deficit during reflexively evoked contractions

Cited by 32 publications

References 42 publications

Effects of quadriceps fatigue on the biomechanics of gait and slip propensity

Effects of quadriceps fatigue on the biomechanics of gait and slip propensity

Considerations for Single and Double Leg Drop Jumps: Bilateral Deficit, Standardizing Drop Height, and Equalizing Training Load

Comparison of maximal unilateral versus bilateral voluntary contraction force

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