Strength and Peak of Amplitude of Rectus Femoris, Vastus Medialis and Vastus Lateralis-Physiotherapy Sample


Need discussion in 4000 words.

Strength and peak of amplitude of rectus-femoris, -vastus-medialis and vastus-Lateralis by using Hand-held dynamometer and Electromyography between healthy male and female,

 The EMG was used as surface EMG normalised mean/peak amplitude by using Maximum muscle isometric contraction and this is the same with Hand held dynamometer
The previous research found that there is a different between sitting and supine position with demonstrating hight muscle torque in sitting position but they used Isokinetic dynamometer which can’t be afford in many clinic and sport environment
The EMG they found a different in quadriceps muscle activity but they used different method which is needle wire insertion EMG, and this mainly used in neurological diseases to identify the muscle action potential instead of muscle function
:The main finding is that there is different between

The first null hypothesis demonstrates that there is no significant difference in the peak isometric quadriceps forces using HHD for the three hip joint positions. Within-subject ANOVA was conducted and provides evidence that there are statistically significant differences in the peak quadriceps muscleforces in healthy people for the three hip joint positions and provides evidence for rejecting the null hypothesis at a 5% level of significance, as p<0.05. Bonferroni test indicates that a significant difference existed between sitting and supine position, while no significant difference between sitting and semi-sitting position. In addition, there was a significant difference between semi-sitting and supine position.

The second null hypothesis indicates that there is no significant difference between males and females regarding peak quadriceps muscle forces for the three hip joint positions. Between-subject ANOVA was used, as the data was normally distributed, and the results of homogeneity and sphericity tests also met the assumption. The test provides evidence for failing to reject the null hypothesis at a 5% level of significance.

The third, fourth and fifth hypotheses indicate that there are no significant differences between the peak MVC of normalised rectus femoris, vastus medialis and vastus lateralis for the three hip joint positions. Within-subject ANOVA provides evidence for failing to reject the null hypothesis at a 5% level of significance, as p>0.05 for all muscles.

The last hypothesis indicates that there is no significant difference between genders regarding the peak normalised MVC for the rectus-Femoris, Vastus-Medialis and Vastus-Lateralis in the three hip joint positions. Between subjects repeated measures ANOVA provides evidence for failing to reject the null hypothesis at a 5% level of significance.



The main purpose of this study is to establish a concurrent validity of electromyography (EMG) activity along with the muscle strength scores obtained by a handheld dynamometer (HHD) for Rectus-Femoris, Vastus-Medialis and Vastus-Lateralis. This paper revolves around 6 hypotheses of which two were declared as null hypotheses in the conclusion of this dissertation. Before we begin the first null hypothesis exhibits that there is no critical distinction in the peak isometric quadriceps powers utilizing Hand Held Dynamometer for the three hip joint positions. Inside subject ANOVA was directed which gave proof that there are measurably noteworthy contrasts in the pinnacle quadriceps muscle powers in solid individuals for the three hip joint positions and gives proof to dismissing the invalid speculation at a 5% dimension of hugeness, as p<0.05. Bonferroni test shows that a critical distinction existed among sitting and supine position, while no huge contrast among sitting and semi-sitting position. Moreover, there was a critical distinction between semi-sitting and supine position.

The second null hypothesis demonstrates that there is no critical distinction among males and females in regards to top quadriceps muscle powers for the three hip joint positions. Between-subject ANOVA was utilized, as the information was ordinarily appropriated, and the consequences of homogeneity and sphericity tests additionally met the supposition. The test gives proof to neglecting to dismiss the invalid speculation at a 5% dimension of importance.

The third, fourth and fifth hypotheses show that there are no huge contrasts between the pinnacle MVC of standardized rectus femoris, vastus medialis and vastus lateralis for the three hip joint positions. Inside subject ANOVA gives proof to neglecting to dismiss the invalid theory at a 5% dimension of criticalness, as p>0.05 for all muscles.

The last hypothesis demonstrates that there is no noteworthy distinction between sexual orientations in regards to the pinnacle standardized MVC for the rectus-Femoris, Vastus-Medialis and Vastus-Lateralis in the three hip joint positions. Between subjects rehashed measures ANOVA gives proof to neglecting to dismiss the invalid theory at a 5% dimension of criticalness.

This paper has witnessed two methods of research viz., the primary method and the doctrinal method and the forthcoming tables, charts and analysis of data has resulted in the aforementioned results.


Knee extension torque is for the most part produced by the quadriceps femoris, which is one of the biggest muscle-bunches in the human body. The quadriceps femoris is made out of the three mono-articular vasti muscles (vastuslateralis (VL), vastusmedialis (VM), vastus intermedius) and the biarticular rectus femoris (RF) muscle. In view of a hypothetical model of RF constrain length relationship, the RF is thought to work over a wide scope of power length attributes in human developments. Amid concentric knee expansions from a flexed knee joint point, RF can be basically on the rising appendage in a flexed hip position, though it very well may be on the slipping appendage in an all-inclusive hip position. Along these lines, amid concentric knee expansions at both moderate and quick rakish speeds, the power producing capability of RF in a flexed hip position may end up littler with knee augmentation and the other way around in an all-inclusive hip position. It is accepted that the distinction in the extent of power potential among flexed and expanded hip positions, relies upon knee joint angles.

The essential use of the quadriceps femoris muscle is to produce knee extensor torque and tostabilize the patella. One strategy that has been used to advance better comprehension of quadriceps muscle work is surface electromyography (EMG). Surface EMG is likewise answered to be a valid and dependable marker of assessing muscle recruitment. Thus, we were keen on EMG parameters, for example, EMG abundance and average recurrence to comprehend the enlistment qualities of quadriceps femoris in most re-seek contemplates. EMG standardization is oftentimes used to enhance unwavering quality by diminishing variety inside and between people in EMG examines.


The present examination tries the speculation, that the impact of hip joint edge on concentric knee expansion torque differs throughout a solitary knee augmentation errand from flexed to broadened knee joint positions. The tool used in this examination for producing the electromyography (EMG) data is a handheld dynamometer (HHD). Muscle quality appraisal, utilizing a HHD may be affected by the analyzer’s quality, obstruction area, and capacity to hold the HHD in a steady position. Scientists need to control these variables, as they may impact the unwavering quality of results. HHD is held by the examiner at the Hip-joint angle placed against the thigh, the limb is properly stabilized and held in a desired starting position. The patient or the subject is instructed to hold his/her limb in a position and resist the force that is applied by examiner. The examiner continues to apply force gradually until the force depresses the limb. The force which is required to move the thigh is known as the ‘breaking force’.

Eleven healthy males and eleven healthy females volunteered to partake in this test. Every one of the member was educated of the benefits and dangers of the examination and accordingly marked a consent document. Measurements were made for all subjects on the quadriceps muscle utilizing a Hand held dynamometer, which permitted chronicle of EMG results.

Electromyography (EMG) recordings:

Surface EMG signals amid the quadriceps muscle preliminaries were acquired from VL, VM and RF of the privilege thigh .After shaving the skin, scouring with sandpaper and cleaning with alcohol, pre-intensified bipolar surface anodes (DE-2.1, 1×10 mm,10mm inter-electrode remove) with band-pass sifting between 20 and450 Hz, were situated at the level of 90% (VM), half (VL and BF) and 30% (RF) of the thigh length, which was characterized as the separation from the more noteworthy trochanter to the popliteal increment. The EMG motion from the vastusmedialis (VM), vastuslateralis (VL), and RF muscles was recorded bipolarly by silver chloride round anodes amid intentional and electrically evoked compressions. The cathodes, having a breadth of 20 mm and a chronicle width of 10 mm, were settled the long way over the centre of the muscle stomach with and between terminal (centre-to-centre) separations of 20 mm. This was done to take into account the inconstancy normally connected with these measurements and all the more especially for the jerk addition results. The pinnacle torque was estimated from the mechanical follows related with resting jerk, resting doublet, and potentiated doublet. Additionally, top to-crest amplitude of the M wave related with single jerk was calculated for VM, VL, and RF muscles. For voluntary contractions, the root mean square (RMS) EMG esteem of VM, VL, and RF muscles was determined over a 500-msperiod around the thigh torque (i.e., 250 ms before and250 ms after the pinnacle). Crude RMS EMG esteems were then normalized to the sufficiency of the maximal M wave for respective muscles and for separate hip positions, in order to research all the more precisely neural activation. Ordinary factual techniques were utilized to ascertain implies, standard deviations (SD), and straight relationship coefficients. Unwavering quality was resolved for all factors by comparing the three preliminaries performed in similar conditions (Table 1).

Table 1:Intraclass correlation coefficients (ICC) and coefficients of variation (CV) for the three trials performed in the participant males and females, for respective variables.


Female (ICC)

Female (CV%)

Male (ICC)

Male (CV%)






Normalized RMS EMG activity
















Activation level (%)





Peak torque



Potentiated Doublet













M-wave Amplitude

VM (mV)

VL (mV)

RF (mV)














Before pushing forward with the discoveries, the constraints of this examination must be mulled over. While utilizing the Hand Held Dynamometer, the situation of the arm and hand can fluctuate in various grasp quality conventions. Different positions incorporate the elbow being held at right points according to the above system, the arm hanging by the side, and the all-encompassing arm being swung from over the go to by the side amid the pressing movement. The Eurofit Test Manual suggests crushing for 3 seconds. The methodology for the Groningen Elderly Tests has the subject drape their hand close by, one practice preliminary, and best of three endeavours with 30 seconds rest between. The dynamometer may need to be adjusted routinely to guarantee predictable outcomes. Having predictable method and sufficient rest is required to guarantee unwavering quality. Likewise, it must be balanced for hand estimate, how effectively this is done will influence the exactness of the estimation.

One hypothesis of this paper states that there’s no critical distinction between males and females in regards to top quadriceps muscle powers for the three hip joint positions. However on the basis of our findings, we can nullify this hypothesis by referring to “Table 1” wherein the difference between the results among the male and female volunteers respectively is clearly visible. The test offers confirmation to fail to expel the invalid hypothesis at a 5% measurement of significance.

Maximal voluntary isometric constriction was fundamentally higher in the males contrasted and the females (Fig. 1; for the correct P values). For the entire gathering, the mean relative distinction between the two sexual orientations was 10.6 ” 11.2%. Standardized RMS EMG esteems were 17.1%, 22.7%, and 41.5% higher in the guys versus the females for VM, VL, and RF muscle, separately. Similarly, enactment level evaluated by methods for the jerk interjection procedure was altogether lower (4.2%) for females. Strangely, relative MVC shortages in females concerning guys were essentially corresponded with individual abatements in actuation level (R % 0.6; P % 0.05). The contrary result was watched for the electrically evoked withdrawals, as single and combined boosts brought about higher torque esteems under females as for guys. It ought to be seen that the most noteworthy the evoked torque, the best the contrast between males versus females esteems. The mean pinnacle torque hole was 10.3% for resting jerk, 15.2% for resting doublet, and 20.1% for the doublet recorded after MVC (i.e., potentiated). Vasti M-wave amplitudes were practically indistinguishable for the two test stances considered, while greater RF possibilities were recorded in the females.

To the best of our insight, this examination is the first to look at VL, VM and RF muscle enactment amid hip positions. In the present examination, no critical impact of hip joint point was seen on RMS-EMG VL, VM and RF muscles, which is mostly conflicting with the after effects of a past report. It detailed that RMS-EMG standardized to M-wave of VL, VM and RF muscle initiation amid hip positions was higher and the M-wave sufficiency of VL, VM and RF muscle enactment amid hip positions was littler in the guys than in the females. The translations of the present discoveries might be excessively theoretical, in light of the fact that we didn’t lead coordinate estimations of RF fascicle conduct and did not assess the real power length relationship of RF. We have affirmed the legitimacy and repeatability of RF fascicle length estimation under a no-compression. Be that as it may, it is vague whether the past strategy can be connected to quantify the RF fascicle conduct amid dynamic constrictions as a result of the muddled structure of the muscle.

The fundamental discoveries of this examination were:

  1. the noteworthy decrease of maximal intentional thigh torque, standardized RMS EMG action and initiation level with expanding RF length (i.e., in the females) and;

  2. The bringing down of RF M-wave abundancy and torque esteems acquired after single and matched incitements of the femoral nerve in the guys.

Torque findings: The 10% gap saw in the present investigation among guys and females isometric MVC is very like the 7– 10% decline in the 30°. Thigh torque esteems as of late revealed at 180° versus 100° hip angle. Interestingly, others have discovered thigh torque to increment with builds hip angle and practically identical isokinetic torque esteems between an upstanding and a semi-leaned back sitting position. In addition, in vivo estimations of RF compel length connections anticipated higher thigh torque-creating limit at the 180° hip angle. This is affirmed in the flow think about by the torque esteems acquired when the headquarters was skirted, i.e., after electrical incitement of resting muscles. Without a doubt, jerk and doublets amplitudes were 10– 20% more noteworthy under females.

It is imperative to take note of that factual power for males versus females doublets was amazingly high. Since these compressions depend solely on muscle properties, the suspicion that protracted RF by means of hip expansion builds thigh torque-creating limit is here affirmed. The littler jerk and doublet evoked in the guys could, in this way be credited to mechanical factors, for example, the diminished RF movement arm or potentially the decreased number of connected cross-spans ensuing to sarcomere shortening beyond the ideal actin-myosin cover. Such a mechanical inconvenience at short muscle lengths has recently been accounted for the thigh torque and plantar flexor muscles.

In addition, the way that RF maximal M-wave recorded here, i.e., neuromuscular transmission-spread, is weakened at short muscle length (see “M wave and neural enactment discoveries”) could essentially impact the related thigh jerk and doublet torque yield and in this manner the whole excitation-withdrawal coupling.

The higher neural enactment recorded here for short RF muscle length is all in all concurrence with past investigations performed on the quadriceps muscles. Be that as it may, these outcomes were ascribed to bring down compressive powers in the patella-femoral joint, as a result of the lower torque created in the abbreviated position. It was not the situation in the present examination. Or maybe, enhanced engine unit release rate and/ormotoneuron sensitivity in the abbreviated RF muscle might be conjectured to be in charge of the higher neural initiation found in the seated position. Indeed, expanded engine unit-terminating rate in the abbreviated biceps brachii and tibialisanterior muscle just as H-reflex extension in the abbreviated quadriceps femoris have as of late been exhibited. Huge numbers of the factors estimated in the present investigation are specifically or by implication between connected. In this manner, we didn’t make any changes for different examinations, as talked about by Bland and Altman and all the more as of late by Perneger, however thought about the outcomes with some alert. All in all, despite the fact that RF muscle gives just a little portion of the all out thigh torque, changes in RF yet not in vasti-muscle length initiated by hip edge control considerably affect the thigh torque yield amid voluntary and electrically evoked constrictions. The higher thigh neural initiation saw in the present investigation under males may mirror a neuro-physiological system mostly remunerating the neuromuscular transmission-engendering weakness and additionally mechanical hindrance (e.g., minute arm) of short RF muscle.


M-wave and neural-initiation discoveries: When considering the crude RMS EMG esteems (information not introduced), a huge deficiency was watched for the male and females. The elucidation of crude EMG results must, notwithstanding, be wary in light of the fact that

(i) Shortening the RF may adjust the cathode design as for the chronicle volume, consequently bringing about an underestimation of the myoelectric movement; and

(ii) Neuromuscular transmission-proliferation might be disabled in an abbreviated muscle. While trying to think about these two components, peak-to-crest M-wave amplitudes related with supra-maximal boosts were recorded.

RF M-wave amplitude significantly diminished with hip flexion, though no progressions were seen among guys and females for vasti M-waves. Comparable discoveries have been accounted for in abbreviated gastrocnemii and tibialis anterior muscle, confirming that neuromuscular transmission-proliferation is impeded at short muscle length. Consequently, to all the more likely portray neural actuation for guys and females, MVC, RMS EMG esteems standardized to separate M waves and maximal deliberate enactment evaluated by methods for the jerk interjection strategy were considered. The main procedure empowered appraisal of each shallow knee extensor muscle to be broke down autonomously, though the second gave an estimation of the compound dimension of deliberate actuation of the muscles innervated by the femoral nerve. By the by, past research explored the impact of hip edge on surface crude EMG action of the knee extensor muscles. Hasler et al. discovered higher EMG esteems for the two vasti at hip joint points of 90° and 180° contrasted and middle of the road hip positions, while 90° and180° EMG movement did not vary essentially. Sadly, torque esteems were not revealed for these subjects so correlations with our EMG results are just recounted. Despite the fact that knee flexor EMG action was not recorded in the present investigation, it has recently been proposed that co-activation likely don’t add to the distinctions in torque yield among male and female MVC. In accordance with Pavol and Grabiner’s assumptions, a considerable decline in neural enactment was seen in the present examination.


In accordance with the primary and doctrinal research above, it is evident that from reviewing the pre-existing literature that there was a vital decline of maximal purposeful thigh torque, institutionalized RMS EMG activity and inception level with extending RF length in the females and the bringing down of RF M-wave abundancy and torque regards gained after single and coordinated actuations of the femoral nerve in the males occurred mainly due to the established fact that there are fundamental differences between males and females regarding peak quadriceps muscle forces for the three hip joint positions. However it was seen that there were no significant differences between the peak MVC of normalised rectus femoris, vastus medialis and vastus lateralis for the three hip joint positions. Also, no significant difference between genders regarding the peak normalised MVC for the rectus-Femoris, Vastus-Medialis and Vastus-Lateralis in the three hip joint positions was seen. Our investigation had a few constraints. Notwithstanding this endeavour to stay away from the predisposition of non-concurrent gathering of solidarity measures, this convention does not reflect every day clinical practice. The outcomes ought to be viewed as substantial for testing with a HHD as it were. They can’t be extrapolated to people in other age bunches with hip issue; these populaces may exhibit factors natural for the individual, for example, physical and psychological well-being concerns, that meddle with dependability, legitimacy, and even the capacity to play out the test. At long last, our investigation had qualities. We affirmed the dependability and legitimacy of the HHD for all thigh-muscle gatherings. The investigation was a creative unwavering quality examination of the rotator muscles of the thigh and assention estimations for all thigh muscle gatherings. In the present examination, standardized VI M-wave adequacy diminished and the term expanded essentially at the hip joint point contrasted and broadened hip joint edge, while the joint edge esteems for VL, RF and VM were similar. This proposed that VI compel age limit declined altogether at the flexed joint edge, however the reductions in VL and VM constrain age limit were comparative at the joint edges in the tried range.

The HHD estimations were recorded amid a similar withdrawal, which approves the connection and assention results, just as the cautiously created and portrayed strategies, which depended on the Guidelines for Reporting Reliability and Agreement Studies; this empowers generation of the tests in the clinical setting. The HHD is a solid and legitimate technique for assessing the quality of the thigh muscle bunches in a sound, youthful grown-up populace and might be utilized in clinical practice.

Spinal reflex action of the vastus-medialis complex likewise varies relying upon the area of the improvement connected. Local stretch reflexes are increasingly distal in light of a distal improvement, recommending that drive from the spinal line likewise differentially enrols engine neurons in the VM and VL have recently appeared engine unit release designs got from the VM and the VL are comparative inside their individual area, however practically less corresponded when the two districts are pooled. In the present examination, VL motor units were enrolled sooner than VM engine units at low power levels. The differential enrolment design between the VM and VL might be identified with natural contrasts in the dissemination of information opposition of the engine units, or it might be because of a tweak in the sensory system to control development. These outcomes additionally give proof of their unmistakable sequential capacities: the VL pulls the patella medially ahead of time of the VM to neutralize the sidelong power of the VL for patellar arrangement. A pattern toward prior VL engine unit enrolment was additionally seen in a situated hip joint angle task. This might not have achieved measurable centrality in light of the fact that the size and heading of patella interpretation created by the withdrawal of the VL and VM contrasts with hip joint point. In the hip joint edge, the patella moves medially when the VL is initiated, and the patella coasts primarily to the proximal heading when the VM is activated. With expanding hip joint edge, there is a decline in the measure of patella average interpretation created by the VL contrasted and the full thigh, though amid thigh flexion there is a vast average move of the patella delivered by the VM contrasted and the completely broadened leg position.

While moving the hip joint in the sagittal plane, the sensory system may react to the removal constrain connected on the patella by changing engine unit movement in the encompassing musculature. When playing out a HHD, horizontal hip turn can diminish the knee augmentation torque required to keep up full hip expansion. This requires less VM actuation than a nonpartisan hip position. Be that as it may, more exercises of everyday life happen with the hip in an impartial position in sagittal plane developments, for example, strolling, running, and biking. Playing out the HHD with nonpartisan hip pivot may create an all the more adequately controlled VM muscle withdrawal that identifies with ordinary movement.

Our information demonstrate that VM in female members display altogether higher beginning terminating rates at enlistment than in male members, in spite of institutionalizing information accumulation to the late follicular stage, when ladies are most like men. This recommends sex is surely a contributing component for the distinctions in rate-coding of the vastusmedialis complex. The measurably noteworthy 1.18 Hz contrast in engine unit terminating rates saw between the genders can contribute considerably to changes in muscle constrain and is viewed as physiologically significant. Female subjects show more prominent extent of moderate jerk fibers and less quick jerk filaments in the VL than male subjects. It is conceivable that distinctions in engine unit release designs in the VM reflect contrasts in engine unit type dispersions between the sexes. The marginal association among sex and hip position for enlistment limit recommends that the female engine units overwhelmingly drove the distinction in enrolment edges between the two hip positions. Females actuate engine units in vastusmedialis complex prior in nonpartisan hip position than in horizontal hip revolution, while male subjects select their engine units at a moderately comparable power level for the two positions. In this manner unique control of the vastusmedialis complex in two hip positions amid focused quadriceps fortifying activity may possibly be progressively useful for female subjects. These sex contrasts may likewise be identified with the finding that ladies figured out how to achieve comparative supreme power dimensions of MVC compel for both hip positions, yet men had a much lower MVC drive in the sidelong hip pivot contrasted and impartial hip turn.

Future investigations are important to assess other clinical exercise conventions that have been supported to specially enact the VM for people with thigh pathology. This will advance progressively custom fitted and powerful VM reinforcing methodologies for both genders. In rundown, we have shown that the VM engine units are enrolled before at lower compel levels contrasted and the VM engine units. Ladies fire their VM units at quicker rates at enrolment than men. The SLR with impartial hip pivot is an increasingly powerful hip position for fortifying the VM in sound people.


  1. Helen C. Roberts, et. al., A review of the measurement of grip strength in clinical and epidemiological studies: towards a standardised approach. Age Ageing (2011) 40 (4): 423-429.

  2. PAVOL, M. J., and M. D. GRABINER. Knee strength variability between individuals across ranges of motion and hip angles. Med.Sci. Sports Exerc. 32:985–992, 2000.

  3. FISHER, N. M., D. R. PENDERGAST, and E. C. CALKINS. Maximal isometric torque of knee extension as a function of muscle length in subjects of advancing age. Arch. Phys. Med. Rehabil. 71:729–734, 1990.

  4. BOHANNON, R. W., R. L. GAJDOSIK, and B. F. LEVEAU. Isokinetic knee flexion and extension torque in the upright sitting and semireclinedsitting positions. Phys. Ther. 66:1083–1086, 1986.

  5. HERZOG, W., and H. E. D. J. TER KEURS. Force-length relation of in-vivo human rectus femoris muscles. Pflu¨gers Arch. 411:642–647, 1988.

  6. VAN INGEN SCHENAU, G. J., W. M. M. DORSSERS, T. G. WELTER, A. BEELEN, G. DE GROOT, and R. JACOBS. The control of mono-articular muscles in multi-joint leg extensions in man. J. Physiol.(Lond.) 481:247–254, 1995.

  7. GORDON, A. M., A. F. HUXLEY, and F. J. JULIAN. The variation in isometric tension with sarcomere length in vertebrate muscle fibers. J. Physiol. (Lond.) 184:170–192, 1966.

  8. BABAULT, N., M. POUSSON, A. MICHAUT, and J. VAN HOECKE. Effect of quadriceps femoris muscle length on neural activation during isometric and concentric contractions. J. Appl. Physiol. 94:983–990, 2003.

  9. CRESSWELL, A. G., W. N. Lo¨SCHER, and A. THORSTENSSON. Influence of gastrocnemius muscle length on triceps surae torque development and electromyographic activity in man. Exp. BrainRes. 105:283–290, 1995.

  10. Pincivero, D.M., Salfetnikov, Y., Campy, R.M., Coelho, A.J., 2004. Angle- and gender specific quadriceps femoris muscle recruitment and knee extensor torque. J. Biomech. 37 (11), 1689–1697.

  11. HUBER A., E. SUTER, and W. HERZOG. Inhibition of the quadriceps muscle in elite male volleyball players. J. Sport Sci. 16:281–289, 1998.

  12. SUTER, E., and W. HERZOG. Extent of muscle inhibition as a function of knee angle. J. Electromyogr. Kinesiol. 7:123 130, 1997.

  13. Wakahara, T., Kanehisa, H., Kawakami, Y., Fukunaga, T., 2007. Fascicle behavior of medial gastrocnemius muscle in extended and flexed knee positions. J. Biomech. 40 (10), 2291–2298.

  14. CHRISTOVA, P., A. KOSSEV, and N. RADICHEVA. Discharge rate of selected motor units in human biceps brachii at different muscle lengths. J. Electromyogr. Kinesiol. 8:287–294, 1998.

  15. VANDER LINDEN D. W., C. G. KUKULKA, and G. L. SODERBERG. The effect of muscle length on motor unit discharge characteristics in human tibialis anterior muscle. Exp. Brain Res. 84:210–218, 1991.

  16. GARLAND, S. J., L. GERILOVSKY, and R. M. ENOKA. Association between muscle architecture and quadriceps femoris H-reflex. Muscle Nerve 17:581–592, 1994.

  17. O’Brien, T.D., Reeves, N.D., Baltzopoulos, V., Jones, D.A., Maganaris, C.N., 2009. Momentarms of the knee extensor mechanism in children and adults. J. Anat. 215 (2), 198–205.

  18. Kawakami, Y., Kubo, K., Kanehisa, H., Fukunaga, T., 2002. Effect of series elasticity on isokinetic torque-angle relationship in humans. Eur. J. Appl. Physiol. 87 (4–5), 381–387.

  19. BLAND, J. M., and D. G. ALTMAN. Multiple significance tests: the Bonferroni method. Br. Med. J. 310:170, 1995.

  20. PERNEGER, T. V. What’s wrong with Bonferroni adjustments? Br. Med. J. 316:1236–1238, 1998.

  21. MCNAIR, P. J., R. N. MARSHALL, and J. A. MATHESON. Quadriceps strength deficit associated with rectus femoris rupture: a case report. Clin. Biomech. 6:190–192, 1991.

  22. Rochette, L., Hunter, S.K., Place, N., Lepers, R., 2003. Activation varies among the knee extensor muscles during a submaximal fatiguing contraction in the seated and supine postures. J. Appl. Physiol. 95 (4), 1515–1522.

  23. Takai, Y., Ohta, M., Akagi, R., Kanehisa, H., Kawakami, Y., Fukunaga, T., 2009. Sit-tostandtest to evaluate knee extensor muscle size and strength in the elderly: a novel approach. J. Physiol. Anthropol. 28 (3), 123–128.

  24. Thorpe, S.K., Li, Y., Crompton, R.H., Alexander, R.M., 1998. Stresses in human leg muscles in running and jumping determined by force plate analysis and from published magnetic resonance images. J. Exp. Biol. 201 (Pt 1), 63–70.

  25. CRESSWELL, A. G., W. N. Lo¨SCHER, and A. THORSTENSSON. Influence of gastrocnemius muscle length on triceps surae torque development and electromyographic activity in man. Exp. BrainRes. 105:283–290, 1995.

  26. GANDEVIA, S. C., and D. K. MCKENZIE. Activation of human muscles at short muscle lengths during maximal static efforts. J. Physiol. (Lond.) 407:599–613, 1988.

  27. SALZMAN, A., L. TORBURN, and J. PERRY. Contribution of rectus femorisand vasti to knee extension: an electromyographic study. Clin. Orthop. Relat. Res. 290:236–243, 1993.

  28. HASLER, E. M., J. DENOTH, A. STACOFF, and W. HERZOG. Influence of hip and knee joint angles on excitation of knee extensor muscles. Electromyogr. Clin. Neurophysiol. 34:355–361, 1994.

  29. VISSER, J. J., J. E. HOOGKAMER, M. F. BOBBERT, and P. A. HUIJING. Length and moment arm of human leg muscles as a function of knee and hip-joint angles. Eur. J. Appl. Physiol. 61:453–460, 1990.

  30. PAVOL, M. J., and M. D. GRABINER. Knee strength variability between individuals across ranges of motion and hip angles. Med.Sci. Sports Exerc. 32:985–992, 2000.

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