Measurement of central activation failure of the quadriceps femoris in healthy adults

Stackhouse, Scott K.; Dean, Jesse C.; Lee, Samuel C. K.; Binder‐Macleod, Stuart A.

doi:10.1002/1097-4598(200011)23:11<1706::aid-mus6>3.0.co;2-b

Cited by 117 publications

(107 citation statements)

References 26 publications

(54 reference statements)

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“…A CAR of 1.0 indicates complete activation of the MN pool (Stackhouse et al, 2000;Lewek et al, 2004). CAR ranges in healthy subjects were previously reported as 0.93-0.99 (Lewek et al, 2004) and 0.95-0.98 (Verbunt et al, 2005).…”

Section: Introductionsupporting

confidence: 75%

Quadriceps activation normative values and the affect of subcutaneous tissue thickness

Park

Hopkins

2011

Journal of Electromyography and Kinesiology

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Section: Introductionsupporting

confidence: 75%

Quadriceps activation normative values and the affect of subcutaneous tissue thickness

Park

Hopkins

2011

Journal of Electromyography and Kinesiology

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“…AL may also be influenced by the actual methodology. Indeed, linear (Norregaard 1997) as well as curvilinear relationships between AL and voluntary torque are commonly obtained (Belanger and McComas 1981;Behm et al 1996;Stackhouse et al 2000). According to Loring and Hershenson (1992), such a nonlinear shape could be due to an increased compliance during sub-maximal voluntary efforts, therefore underestimating the resultant AL.…”

Section: Discussionmentioning

confidence: 63%

EMG activity and voluntary activation during knee-extensor concentric torque generation

et al. 2002

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This study was designed to re-examine and compare the neural drive of the knee extensors during isokinetic concentric muscular actions by means of the twitch interpolation technique (activation level, AL) and surface electromyographic (EMG) recordings (root mean square, RMS). Torque, AL and RMS amplitudes of three knee extensors and one knee flexor were measured in nine subjects during maximal and sub-maximal voluntary contractions, performed under concentric (60 degrees.s(-1) and 120 degrees.s(-1); Con60 and Con120, respectively) and isometric (Iso) conditions. Mean (SD) maximal voluntary torque was significantly lower ( P<0.01) during concentric contractions [Con60: 208.6 (26.8) Nm and Con120: 184.7 (26.4) Nm] compared with isometric contractions [327.4 (52.0) Nm]. A significantly lower AL ( P<0.05) was recorded during Con60 [80.9 (8.8)%] compared with Iso [87.9 (5.1)%] and Con120 [88.2 (6.6)%] maximal contractions. Simultaneously, a lower knee extensor average RMS amplitudes (av.RMS) was measured during Con60 maximal contractions compared with Iso and Con120 maximal contractions. The antagonist biceps femoris RMS values were not different between maximal Iso, Con60 and Con120 contractions. During sub-maximal voluntary contractions, the RMS/torque relationships were similar whatever the muscle considered (vastus lateralis, vastus medialis or rectus femoris) and the AL/av.RMS relationships did not reveal any noticeable differences between each contractile condition. The results of the present study indicate that av.RMS and AL describe similarly the neural drive during maximal and sub-maximal efforts and indicate that during maximal voluntary efforts, neural drive is dependent upon concentric angular velocity (up to 120 degrees.s(-1)). Thus, our results suggest that when applying different contractile conditions, the torque output is regulated via complex interactions between intrinsic muscular properties and the neural drive.

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“…Our results indicated that activation level played no role in explaining the bone strength. There seemed to be some variation in activation level among individuals, but evidently activation level is not a major determinative factor in force production in young adults (Merton 1954;Oskouei et al 2003;Stackhouse et al 2000). As has been shown previously, our results suggest that, in addition to variation in muscle volume, there is significant inter-individual variation in specific tension (Ikai and Fukunaga 1968;Maughan and Nimmo 1984), which also plays a role in determining the bone strength.…”

Section: Discussionmentioning

confidence: 70%

Neuromuscular performance and bone structural characteristics in young healthy men and women

et al. 2007

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Muscle mass and strength have been shown to be important factors in bone strength. Low muscular force predisposes to falling especially among elderly. Regular exercise helps to prevent falls and resulting bone fractures. Better understanding of muscle function and its importance on bone properties may thus add information to fracture prevention. Therefore the purpose of this study was to examine the relationship between bone strength and muscular force production. Twenty-young men [24 (2) years] and 20 [24 (3) years] women served as subjects. Bone compressive (BSI(d)) and bending strength indices (50 Imax) were measured with peripheral quantitative computed tomography (pQCT) at tibial mid-shaft and at distal tibia. Ankle plantarflexor muscle volume (MV) was estimated from muscle thickness measured with ultrasonography. Neuromuscular performance was evaluated from the measurements of maximal ground reaction force (GRF) in bilateral jumping and of eccentric maximal voluntary ankle plantarflexor torque (MVC). Specific tension (ST) of the plantarflexors was calculated by dividing the MVC with the muscle volume. Activation level (AL) was measured with superimposed twitch method. Distal tibia BSI(d) and tibial mid-shaft 50 Imax correlated positively with GRF, MVC and MV in men (r = 0.45-0.67, P < 0.05). Tibial mid-shaft 50 Imax and neuromuscular performance variables were correlated in women (r = 0.46-0.59, P < 0.05), whereas no correlation was seen in distal tibia. In the regression analysis, MV and ST could explain 64% of the variance in tibial mid-shaft bone strength and 41% of the variation in distal tibia bone strength. The study emphasizes that tibial strength is related to maximal neuromuscular performance. In addition, tibial mid-shaft seems to be more dependent on the neuromuscular performance, than distal tibia. In young adults, the association between bone adaptation and neuromuscular performance seems to be moderate and also site and loading specific.

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Measurement of central activation failure of the quadriceps femoris in healthy adults

Cited by 117 publications

References 26 publications

Quadriceps activation normative values and the affect of subcutaneous tissue thickness

Quadriceps activation normative values and the affect of subcutaneous tissue thickness

EMG activity and voluntary activation during knee-extensor concentric torque generation

Neuromuscular performance and bone structural characteristics in young healthy men and women

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