Int J Physiother Res 20142(6)766-71 ISSN 2321-1822 766

Review Article

FORCE COUPLE MECHANICS ON FEMUR DURING CLOSED KINETICCHAIN ACTIVITIES OF LOWER LIMBSRVinodh RajkumarFounder PALEOLITHICX Physiotherapist amp Functional Fitness Training Instructor (Freelance)Bangalore Karnataka India

Exploration of the biomechanical interaction of musculoskeletal system keeps endorsing the fact that thehuman body can ensure efficient biomechanics without any kinematic aberrations in the joints Excluding theinjuries caused by unexpected collisions the major potential factors that ruin the protective configuration ofmusculoskeletal system can be lack of exercise and incorrect exercise A fresh perspective lsquoforce couplemechanics (FCM) on femurrsquo (torque on femur by two muscular forces in opposite directions at two differentlocations) has been discussed in this article using fundamental information on anatomical linkages of musclesamp correlation of various scientific reports finally expected to stimulate electromyographic studies to dig outfurther scientific dataKEYWORDS Force couple mechanics on femur Gluteus maximus Vasti

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International Journal of Physiotherapy and ResearchISSN 2321- 1822

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ABSTRACT

INTRODUCTION

Address for correspondence R Vinodh Rajkumar 638 1st Floor Jakkuramma Building BehindEswara Temple 1st Cross 1st Main Mathikere Bangalore-560054 Karnataka IndiaMobile 9008424632 E-Mail dreamofkalamrediffmailcom

International Journal of Physiotherapy and ResearchInt J Physiother Res 2014 Vol 2(6)766-71 ISSN 2321-1822

DOI 1016965ijpr2014689

Exploration of the biomechanical interaction ofmusculoskeletal system keeps endorsing the factthat the human body can ensure efficientbiomechanics without any kinematic aberrationsin the joints Excluding the injuries caused byunexpected collisions the major potentialfactors that ruin the protective configuration ofmusculoskeletal system can be lack of exerciseand incorrect exercise A fresh perspective lsquoforcecouple mechanics (FCM) on femurrsquo (torque onfemur by two muscular forces in opposite direc-tions at two different locations) has beendiscussed in this article using fundamentalinformation on anatomical linkages of musclesamp correlation of various scientific reports finallyexpected to stimulate electromyographic stud-ies to dig out further scientific data

Biomechanical analysisTo understand the role of FCM on femur thefundamental of closed kinetic chain angularmotion has to be understood as follows ldquoIf apush force is applied on a stable surface throughone terminal part of a rigid lever (point-A) thenthe other terminal part (B) will tend to moveaway from its original position using point-A asaxis to result in angular displacement (oslash) of theentire lever but to get this type of mechanicalinteraction during closed kinetic chaincircumstances in human body a force couplesystem (F1 F2) must act on that leverrdquo - Figure1a 1bThe stability of the lever at point-A is verycrucial if the goal of the FCM is to lift point-Bupwardly without any scope for it to getdisplaced in any unintended direction At the

DOI 1016965ijpr2014689

Accepted 03-11-2014Published (O) 23-11-2014Published (P) 11-12-2014

Received 19-10-2014Peer Review 19-10-2014Revised None

Int J Physiother Res 20142(6)766-71 ISSN 2321-1822 767

R V inodh Rajkumar FORCE COUPLE MECHANICS ON FEMUR DURING CLOSED KINETIC CHAIN ACTIVITIES OF LOWER LIMBS

same time the direction of application of F1 ampF2 is also important to get this rotational effecton the lever For instance if the F1 amp F2 are ap-plied on the lever as shown in Figure-1c thenthe mechanical outcome will be entirely differ-ent in which point A will tend to move away fromthe stable surface

Fig 1 Fundamental of closed kinetic chain angularmotion

The femur being a rigid skeletal lever also tendsto move similarly in the sagittal plane duringvarious closed kinetic chain (CKC) movementsof lower extremities In this article squat hasbeen chiefly considered for a sagittal planeanalysis to interpret the probable force couplemuscular system and other supportivebiomechanics essential for effective FCM onfemur during CKC activities of lower extremitiesAs a result of force couple mechanics at theproximal part of femur the femoral condylesmust apply compressive force on the stable tibialplateau (Figure-2a) resulting in upward angulardisplacement (oslash) of the femur (Figure-2b) It iseasy to identify the muscular system involvedin FCM on femur because for sure the point ofapplication of force that pulls the femurdownward should be located distal to the pointof application of force that pulls the femurupward From anatomical view point Gluteusmaximus can apply the downward force atgluteal tuberosity located distal to the origin ofVasti group (Vastus lateralis Vastus medialis ampVastus intermedius) of Quadriceps which canexert the upward force (Figure-2c) Caterisanoet al indicated the increasing activity of GluteusMaximus (GM) as the squat depth increases1

Escamilla et al found that the EMG activity ofVasti (V) was greater than Rectus femoris andthe muscular force output of Vasti was 50greater than that of Rectus femoris2

When F1 and F2 are acting as force couples ona rigid skeletal lever in the body particularly ifany heavy load is placed at or near the movableend of the lever the F1 (component that is closerto the movable end) can act like a fulcrum Thefunction of Vasti in FCM on femur can beinterpreted as a fulcrum whilst the role of GM isto counterbalance the torque caused by massof Head Arms and Trunk (mass of HAT) placedon the femoral head to ultimately executecontrol over the angular displacement of femurduring ascent and descent of squat (Figure-3a3b) The work load for Vasti and Gluteus maximusduring squat is quite larger because thepercentage contribution of the mass of HAT tothe total body mass of an individual itself basedon the studies of body segment parameters ofde Leva and Plagenhoef et al can be up to 5926 and 7312 respectively34 However Pearsallet al did a review on studies about body segmentparameters and suggested that the future effortsin this context should be directed towardsaddressing its various weaknesses in order toimprove biomechanical investigation in theclinical ergonomic and sport environments5

Fig 2 Force couple mechanics on femur

Fig 3 Interaction of HAT Vasti and Gluteus maximus

By acting like a fulcrum the Vasti can form afirst class lever system with much lesserresistance arm (RA) for Gluteus maximus (Fig-ure-4b) as compared to the resistance arm of

Int J Physiother Res 20142(6)766-71 ISSN 2321-1822 768

R V inodh Rajkumar FORCE COUPLE MECHANICS ON FEMUR DURING CLOSED KINETIC CHAIN ACTIVITIES OF LOWER LIMBS

Vasti (Figure-4a) To effectively maneuver thisforce couple mechanics on femur two majorsupportive biomechanics may be required (i)Strong working foundation for Gluteus maximusand Vasti (ii) Stable axis at knee jointGluteus maximus must apply strong forces ongluteal tuberosity of femur without causing aposterior pelvic tilt so its proximal attachmentsite must be stabilized Iliopsoas can help increating a working foundation as they can actas an antagonist to the gluteal muscles tocontrol posterior pelvic tilt during squat6

Generally the pelvic stability and its alignmentin the sagittal plane can also be expectedthrough co-contraction of Rectus femoris andHamstrings In sagittal plane the anatomicallinkage of Rectus femoris and Hamstrings onpelvis and knee simulates the inter-dependentactivities of dissimilar sized pulleys used inmachines (Figure-5) Through such arrangementRectus femoris and Hamstrings muscularsystem can constantly have direct reciprocalcontrol on pelvic alignment in the sagittal planewhich in turn induces necessary changes in thetrunk muscle recruitment to stabilize thevertebral column During Gluteus maximuscontraction in this CKC circumstance the pelviscan be prevented from tilting posteriorly if theactivity of Rectus femoris remains greater thanthe Hamstrings The role of Rectus femoris maybe crucial during the disruption of upright stand-ing posture to initiate squat and that can becorrelated with decreased activities ofHamstrings during initiation of squat as reportedby Cheron et al whilst the concomitant role ofTibialis anterior in initiating squat was recog-nized by Cheron et al amp Valdeci et al78 HenceIliopsoas and Rectus femoris can preventposterior tilting of pelvis and provide a strongworking foundation for Gluteus maximus to acton femurFig 4 Formation of first class lever system for Gluteus

maximus by Vasti

Fig 5 Sagittal view of arrangement of Rectus femorisand Hamstrings resembling interaction of mechanicalpulleys HJ - Hip joint KJ - Knee joint AJ- Ankle jointPF - Plantar flexors DF - Dorsiflexors P - Pelivs Q -

Quadriceps H - Hamstrings R ndash Ribcage

Fig 6 Possible advantage of anterior inclination oftibial plateau and presence of patella HJ - Hip joint

AJ - Ankle joint TP - Tibial plateau FC - Femoralcondyle Pat ndash Patella

On the other hand the Vasti muscles must applystrong forces on inter-trochanteric region offemur with its distal attachment site stabilizedto prevent unwanted knee extension thrust(similar to knee extension in open kinetic chain)and disturbances in the knee joint axis causedby anterior translation effects on tibia The kneeextension thrust caused by Quadriceps getseasily neutralized by CKC ankle dorsiflexion andtransmission of sufficient load through the lowerextremities resulting in increased friction at theinterface between feet and floor At the sametime the tendency of Quadriceps to produceanterior translation effects on tibia can get offsetby Hamstrings as it is believed to exert acounter-regulatory pull on the tibia to alleviatestress on the anterior cruciate ligament 910

Stable axis at knee joint is very crucial foreffective FCM on femur although the sagittalplane orientation of the tibial plateau (TP) will

Int J Physiother Res 20142(6)766-71 ISSN 2321-1822 769

R V inodh Rajkumar FORCE COUPLE MECHANICS ON FEMUR DURING CLOSED KINETIC CHAIN ACTIVITIES OF LOWER LIMBS

be under the control of dorsiflexors and plantarflexors CKC dorsiflexion of ankle displaces theknee joints downwardly and forwardly produc-ing anterior inclination of tibial plateau whilstthe CKC plantarflexion of ankle displaces theknee joints upwardly and backwardly with thetendency to restore the horizontal orientationof tibial plateau Various supportive mechanismscan be facilitating perfect spinning of femoralcondyles on the tibial plateau not only in favorof protecting the knee from injuries but also infavor of this force couple mechanics on femurApart from executing postural control the CKCankle dorsiflexion during squat may possessmultiple biomechanical advantages by tilting thetibia and tibial plateau anteriorly Anteriorinclination of tibial plateau can also facilitatethe required anterior gliding of femoral condyleto reduce the stress in anterior cruciate ligament(ACL) during initial stages of flexion of knee inCKC Hamstrings activity has been linked withreducing stress on ACL and its peak activity wasfound to occur anywhere between 10deg and 70degof knee flexion11 So the anterior inclination oftibial plateau and Hamstrings activity maytogether play a vital role to safeguard ACLespecially when the Quadriceps activity tendsto peak Peak activity of Quadriceps has beennoted at approximately 80deg to 90deg of kneeflexion9 Any excess anterior gliding of femoralcondyle can also be retarded by patella toprevent elevation of the stress in posteriorcruciate ligament (PCL) or by PCL to preventelevation of patellofemoral joint reaction forces(Figure 6a6b) Shields et al studying theco-contraction between the Quadriceps and theHamstrings in the squat exercise in three loadlevels have verified that the activity of theQuadriceps muscle was higher than theHamstrings for all levels12 PCL forces whichwere generated throughout the squat descentand ascent progressively increased as the kneesflexed and decreased as the knees extended13

Controlled dorsiflexion caused by Soleus can beanother supportive system to neutralize theanterior tibial translation effects of QuadricepsThe Soleus muscle slows down the ankledorsiflexion and creates a knee extensiontorque forcing the tibia backwards which

minimizes the anterior shear force in the kneejoint14 Posterior tibiofemoral shear force on ACL-intact knees indicated that the potential loadingon the injured or reconstructed anterior cruciateligament is not significant and also themagnitude of the posterior tibiofemoral shearforce is not likely to be detrimental to the injuredor reconstructed posterior cruciate ligament15

Deep squats and activities with deep kneeflexions (Photograph - 1 amp 2) could demandgreater magnitude of angular displacement offemur and the total work output from FCM onfemur Knee structures are highly constrained atangles greater than 120deg resulting in much lessanterior and posterior tibial translation and tibialrotation in comparison with lesser flexionangles16 Dislocating effect on the knee causedby compression of posterior thigh and calfmuscles has been one of the concerns of deepsquat according to Kreighbaum et al17 In deepknee flexion angles the ACL and PCL can almostget aligned horizontally and verticallyrespectively through which the dislocatingeffects on the knee caused by compression ofposterior thigh and calf muscles may getprevented However failure to control the squatdescent can result in the ballistic contactbetween the hamstrings and calf muscles whichcan cause a dislocating effect on the kneeligaments18 Hence when all such protectivemechanisms work in perfect balance the axisat knee joint can remain stable to effectivelysupport the FCM on femurPhotograph 1 Deep squat Photograph 2 Climbing up

high platform

The major biomechanical challenge during CKCactivities of lower extremities is to move thetrunk in the purposeful directions oftenassociated with purposeful activities of upper

Int J Physiother Res 20142(6)766-71 ISSN 2321-1822 770

R V inodh Rajkumar FORCE COUPLE MECHANICS ON FEMUR DURING CLOSED KINETIC CHAIN ACTIVITIES OF LOWER LIMBS

extremities for which spinal stability is vitalStability of spine is determined by activationlevels of all trunk muscles regardless of themagnitude of Intra-abdominal pressure (IAP) andthe effectiveness of IAP becomes mosteffective at stabilizing the spine when appliedin concert with co-activation of the Erectorspinae muscles19 Any increased hoop tensioncreated by the Transversus abdominus andInternal oblique abdominal muscles would serveto not only increase IAP but it would alsoincrease segmental joint stiffness and serve tostabilize the spine in all planes of motion20 Butthe recruitment of trunk muscles may dependon the mechanisms that ensure stability ofpelvis and knee joint to support the FCM onfemur For example the abdominal musclesshould enhance the stability of lumbar spinewhile Iliopsoas contracts to provide workingfoundation for Gluteus maximus during FCM onfemur

CONCLUSION

From biomechanical perspective a wide rangeof CKC activities of lower extremities thatincorporates knee flexion and ankle dorsiflex-ion irrespective of the magnitude of range ofmotion may be inevitably relying on this forcecouple muscular system on femur howeverelectromyographic studies on the basis of thisconcept is warranted to dig out relevant scien-tific data This concept of FCM on femur and itsrelated supportive biomechanics can also be partof the future research efforts in the field ofPhysical therapy rehabilitation and fitnesstraining to further enhance the understandingof biomechanics of CKC activities like stairclimbing squats lunges bent-knee dead liftsjumps and all other locomotion

Conflicts of interest None

REFERENCES

3 De Leva P Adjustments to Zatsiorsky-SeluyanovrsquosSegment Inertia Parameters Journal ofBiomechanics 199629(9)1223-1230

4 Plagenhoef S Evans FG Abdelnour T Anatomicaldata for analyzing human motion ResearchQuarterly for Exercise and Sport 198354169-178

5 Pearsall DJ Reid JG The study of human bodysegment parameters in biomechanics An historicalreview and current status report Sports Med 1994Aug18(2)126-40

6 Mike Decker Jake Krong Dan Peterson Tyler AnstettMichael Torry Erik Giphart Kevin ShelburneMarcPhilippon Deep hip muscle activation during asquat exercise Retrieved from httpwwwasbweborgconferences2009943pdf

7 Cheron G Bengoetxea A Pozzo T Bourgeois M DrayeJP Evidence of a preprogrammed deactivation ofthe hamstring muscles for triggering rapid changesof posture in humans Electroenceph ClinNeurophysiol 199710558ndash71

8 Valdeci Carlos Dionisio Gil Lucio Almeida MarcosDuarte Rogerio Pessoto Hirata Kinematic Kineticand EMG patterns during downward squattingJournal of Electromyography and Kinesiology200818134-143

9 Escamilla RF Knee biomechanics of the dynamicsquat exercise Med Sci Sports Exerc 200133127ndash141 2001

10 Yasuda K and T Sasaki Exercise after anteriorcruciate ligament reconstruction the force exertedon the tibia by the separate isometric contractionsof the quadriceps or the hamstringsClinOrthop1987 220275ndash283

11 Senter C Hame SL Biomechanical analysis of tibialtorque and knee flexion angle Implications forunderstanding knee injury Sports Med200636635ndash641

12 Shields RK Madhavan S Gregg E Leitch J PetersenB Salata S et al Neuromuscular control of the kneeduring a resisted single-limb squat exercise Am JSports Med 2005331520-6

13 Toutoungi DE TWLu A Leardini F Catani and JJOrsquoConnor Cruciate ligament forces in the humanknee during rehabilitation exercises Clin Biomech200015176 ndash187

14 Elias JJ Faust AF Chu Y Chao EY Cosgarea AJ Thesoleus muscle acts as an agonist for the anteriorcruciate ligament an in vitro experimental studyAm J Sports Med 200331241-6

15 Stuart MJ Meglan DA Lutz GE Growney ES An KNComparison of intersegmental tibiofemoral jointforces and muscle activity during various closedkinetic chain exercises Am J Sports Med 1996 Nov-Dec24(6)792-9

16 Li G DeFrate LE Rubash HE and Gill TJ In vivokinematics of the ACL during weight bearing kneeflexion J Orthop Res 200523340-344

17 Kreighbaum E Katharine BM Biomechanics AQualitative Approach for Studying HumanMovement Allyn amp Bacon 1996Pgs 203-204

1 Caterisano A Moss RF Pellinger TK Woodruff KLewis VC Booth W Khadra T The effect of backsquat depth on the EMG activity of 4 superficialhip and thigh muscles J Strength Cond Res Aug2002 16(3) 428-32

2 Escamilla RF Fleisig GS Zheng N Barrentine SWWilk KE Andrews JR Biomechanics of the kneeduring closed kinetic and open kinetic chainexercises Med Sci Sport Exerc 199830556-69

Int J Physiother Res 20142(6)766-71 ISSN 2321-1822 768

R V inodh Rajkumar FORCE COUPLE MECHANICS ON FEMUR DURING CLOSED KINETIC CHAIN ACTIVITIES OF LOWER LIMBS

Vasti (Figure-4a) To effectively maneuver thisforce couple mechanics on femur two majorsupportive biomechanics may be required (i)Strong working foundation for Gluteus maximusand Vasti (ii) Stable axis at knee jointGluteus maximus must apply strong forces ongluteal tuberosity of femur without causing aposterior pelvic tilt so its proximal attachmentsite must be stabilized Iliopsoas can help increating a working foundation as they can actas an antagonist to the gluteal muscles tocontrol posterior pelvic tilt during squat6

Generally the pelvic stability and its alignmentin the sagittal plane can also be expectedthrough co-contraction of Rectus femoris andHamstrings In sagittal plane the anatomicallinkage of Rectus femoris and Hamstrings onpelvis and knee simulates the inter-dependentactivities of dissimilar sized pulleys used inmachines (Figure-5) Through such arrangementRectus femoris and Hamstrings muscularsystem can constantly have direct reciprocalcontrol on pelvic alignment in the sagittal planewhich in turn induces necessary changes in thetrunk muscle recruitment to stabilize thevertebral column During Gluteus maximuscontraction in this CKC circumstance the pelviscan be prevented from tilting posteriorly if theactivity of Rectus femoris remains greater thanthe Hamstrings The role of Rectus femoris maybe crucial during the disruption of upright stand-ing posture to initiate squat and that can becorrelated with decreased activities ofHamstrings during initiation of squat as reportedby Cheron et al whilst the concomitant role ofTibialis anterior in initiating squat was recog-nized by Cheron et al amp Valdeci et al78 HenceIliopsoas and Rectus femoris can preventposterior tilting of pelvis and provide a strongworking foundation for Gluteus maximus to acton femurFig 4 Formation of first class lever system for Gluteus

maximus by Vasti

Fig 5 Sagittal view of arrangement of Rectus femorisand Hamstrings resembling interaction of mechanicalpulleys HJ - Hip joint KJ - Knee joint AJ- Ankle jointPF - Plantar flexors DF - Dorsiflexors P - Pelivs Q -

Quadriceps H - Hamstrings R ndash Ribcage

Fig 6 Possible advantage of anterior inclination oftibial plateau and presence of patella HJ - Hip joint

AJ - Ankle joint TP - Tibial plateau FC - Femoralcondyle Pat ndash Patella

On the other hand the Vasti muscles must applystrong forces on inter-trochanteric region offemur with its distal attachment site stabilizedto prevent unwanted knee extension thrust(similar to knee extension in open kinetic chain)and disturbances in the knee joint axis causedby anterior translation effects on tibia The kneeextension thrust caused by Quadriceps getseasily neutralized by CKC ankle dorsiflexion andtransmission of sufficient load through the lowerextremities resulting in increased friction at theinterface between feet and floor At the sametime the tendency of Quadriceps to produceanterior translation effects on tibia can get offsetby Hamstrings as it is believed to exert acounter-regulatory pull on the tibia to alleviatestress on the anterior cruciate ligament 910

Stable axis at knee joint is very crucial foreffective FCM on femur although the sagittalplane orientation of the tibial plateau (TP) will

Int J Physiother Res 20142(6)766-71 ISSN 2321-1822 769

R V inodh Rajkumar FORCE COUPLE MECHANICS ON FEMUR DURING CLOSED KINETIC CHAIN ACTIVITIES OF LOWER LIMBS

be under the control of dorsiflexors and plantarflexors CKC dorsiflexion of ankle displaces theknee joints downwardly and forwardly produc-ing anterior inclination of tibial plateau whilstthe CKC plantarflexion of ankle displaces theknee joints upwardly and backwardly with thetendency to restore the horizontal orientationof tibial plateau Various supportive mechanismscan be facilitating perfect spinning of femoralcondyles on the tibial plateau not only in favorof protecting the knee from injuries but also infavor of this force couple mechanics on femurApart from executing postural control the CKCankle dorsiflexion during squat may possessmultiple biomechanical advantages by tilting thetibia and tibial plateau anteriorly Anteriorinclination of tibial plateau can also facilitatethe required anterior gliding of femoral condyleto reduce the stress in anterior cruciate ligament(ACL) during initial stages of flexion of knee inCKC Hamstrings activity has been linked withreducing stress on ACL and its peak activity wasfound to occur anywhere between 10deg and 70degof knee flexion11 So the anterior inclination oftibial plateau and Hamstrings activity maytogether play a vital role to safeguard ACLespecially when the Quadriceps activity tendsto peak Peak activity of Quadriceps has beennoted at approximately 80deg to 90deg of kneeflexion9 Any excess anterior gliding of femoralcondyle can also be retarded by patella toprevent elevation of the stress in posteriorcruciate ligament (PCL) or by PCL to preventelevation of patellofemoral joint reaction forces(Figure 6a6b) Shields et al studying theco-contraction between the Quadriceps and theHamstrings in the squat exercise in three loadlevels have verified that the activity of theQuadriceps muscle was higher than theHamstrings for all levels12 PCL forces whichwere generated throughout the squat descentand ascent progressively increased as the kneesflexed and decreased as the knees extended13

Controlled dorsiflexion caused by Soleus can beanother supportive system to neutralize theanterior tibial translation effects of QuadricepsThe Soleus muscle slows down the ankledorsiflexion and creates a knee extensiontorque forcing the tibia backwards which

minimizes the anterior shear force in the kneejoint14 Posterior tibiofemoral shear force on ACL-intact knees indicated that the potential loadingon the injured or reconstructed anterior cruciateligament is not significant and also themagnitude of the posterior tibiofemoral shearforce is not likely to be detrimental to the injuredor reconstructed posterior cruciate ligament15

Deep squats and activities with deep kneeflexions (Photograph - 1 amp 2) could demandgreater magnitude of angular displacement offemur and the total work output from FCM onfemur Knee structures are highly constrained atangles greater than 120deg resulting in much lessanterior and posterior tibial translation and tibialrotation in comparison with lesser flexionangles16 Dislocating effect on the knee causedby compression of posterior thigh and calfmuscles has been one of the concerns of deepsquat according to Kreighbaum et al17 In deepknee flexion angles the ACL and PCL can almostget aligned horizontally and verticallyrespectively through which the dislocatingeffects on the knee caused by compression ofposterior thigh and calf muscles may getprevented However failure to control the squatdescent can result in the ballistic contactbetween the hamstrings and calf muscles whichcan cause a dislocating effect on the kneeligaments18 Hence when all such protectivemechanisms work in perfect balance the axisat knee joint can remain stable to effectivelysupport the FCM on femurPhotograph 1 Deep squat Photograph 2 Climbing up

high platform

The major biomechanical challenge during CKCactivities of lower extremities is to move thetrunk in the purposeful directions oftenassociated with purposeful activities of upper

Int J Physiother Res 20142(6)766-71 ISSN 2321-1822 770

R V inodh Rajkumar FORCE COUPLE MECHANICS ON FEMUR DURING CLOSED KINETIC CHAIN ACTIVITIES OF LOWER LIMBS

extremities for which spinal stability is vitalStability of spine is determined by activationlevels of all trunk muscles regardless of themagnitude of Intra-abdominal pressure (IAP) andthe effectiveness of IAP becomes mosteffective at stabilizing the spine when appliedin concert with co-activation of the Erectorspinae muscles19 Any increased hoop tensioncreated by the Transversus abdominus andInternal oblique abdominal muscles would serveto not only increase IAP but it would alsoincrease segmental joint stiffness and serve tostabilize the spine in all planes of motion20 Butthe recruitment of trunk muscles may dependon the mechanisms that ensure stability ofpelvis and knee joint to support the FCM onfemur For example the abdominal musclesshould enhance the stability of lumbar spinewhile Iliopsoas contracts to provide workingfoundation for Gluteus maximus during FCM onfemur

CONCLUSION

From biomechanical perspective a wide rangeof CKC activities of lower extremities thatincorporates knee flexion and ankle dorsiflex-ion irrespective of the magnitude of range ofmotion may be inevitably relying on this forcecouple muscular system on femur howeverelectromyographic studies on the basis of thisconcept is warranted to dig out relevant scien-tific data This concept of FCM on femur and itsrelated supportive biomechanics can also be partof the future research efforts in the field ofPhysical therapy rehabilitation and fitnesstraining to further enhance the understandingof biomechanics of CKC activities like stairclimbing squats lunges bent-knee dead liftsjumps and all other locomotion

Conflicts of interest None

REFERENCES

3 De Leva P Adjustments to Zatsiorsky-SeluyanovrsquosSegment Inertia Parameters Journal ofBiomechanics 199629(9)1223-1230

4 Plagenhoef S Evans FG Abdelnour T Anatomicaldata for analyzing human motion ResearchQuarterly for Exercise and Sport 198354169-178

5 Pearsall DJ Reid JG The study of human bodysegment parameters in biomechanics An historicalreview and current status report Sports Med 1994Aug18(2)126-40

6 Mike Decker Jake Krong Dan Peterson Tyler AnstettMichael Torry Erik Giphart Kevin ShelburneMarcPhilippon Deep hip muscle activation during asquat exercise Retrieved from httpwwwasbweborgconferences2009943pdf

7 Cheron G Bengoetxea A Pozzo T Bourgeois M DrayeJP Evidence of a preprogrammed deactivation ofthe hamstring muscles for triggering rapid changesof posture in humans Electroenceph ClinNeurophysiol 199710558ndash71

8 Valdeci Carlos Dionisio Gil Lucio Almeida MarcosDuarte Rogerio Pessoto Hirata Kinematic Kineticand EMG patterns during downward squattingJournal of Electromyography and Kinesiology200818134-143

9 Escamilla RF Knee biomechanics of the dynamicsquat exercise Med Sci Sports Exerc 200133127ndash141 2001

10 Yasuda K and T Sasaki Exercise after anteriorcruciate ligament reconstruction the force exertedon the tibia by the separate isometric contractionsof the quadriceps or the hamstringsClinOrthop1987 220275ndash283

11 Senter C Hame SL Biomechanical analysis of tibialtorque and knee flexion angle Implications forunderstanding knee injury Sports Med200636635ndash641

12 Shields RK Madhavan S Gregg E Leitch J PetersenB Salata S et al Neuromuscular control of the kneeduring a resisted single-limb squat exercise Am JSports Med 2005331520-6

13 Toutoungi DE TWLu A Leardini F Catani and JJOrsquoConnor Cruciate ligament forces in the humanknee during rehabilitation exercises Clin Biomech200015176 ndash187

14 Elias JJ Faust AF Chu Y Chao EY Cosgarea AJ Thesoleus muscle acts as an agonist for the anteriorcruciate ligament an in vitro experimental studyAm J Sports Med 200331241-6

15 Stuart MJ Meglan DA Lutz GE Growney ES An KNComparison of intersegmental tibiofemoral jointforces and muscle activity during various closedkinetic chain exercises Am J Sports Med 1996 Nov-Dec24(6)792-9

16 Li G DeFrate LE Rubash HE and Gill TJ In vivokinematics of the ACL during weight bearing kneeflexion J Orthop Res 200523340-344

17 Kreighbaum E Katharine BM Biomechanics AQualitative Approach for Studying HumanMovement Allyn amp Bacon 1996Pgs 203-204

1 Caterisano A Moss RF Pellinger TK Woodruff KLewis VC Booth W Khadra T The effect of backsquat depth on the EMG activity of 4 superficialhip and thigh muscles J Strength Cond Res Aug2002 16(3) 428-32

2 Escamilla RF Fleisig GS Zheng N Barrentine SWWilk KE Andrews JR Biomechanics of the kneeduring closed kinetic and open kinetic chainexercises Med Sci Sport Exerc 199830556-69

Int J Physiother Res 20142(6)766-71 ISSN 2321-1822 769

R V inodh Rajkumar FORCE COUPLE MECHANICS ON FEMUR DURING CLOSED KINETIC CHAIN ACTIVITIES OF LOWER LIMBS

be under the control of dorsiflexors and plantarflexors CKC dorsiflexion of ankle displaces theknee joints downwardly and forwardly produc-ing anterior inclination of tibial plateau whilstthe CKC plantarflexion of ankle displaces theknee joints upwardly and backwardly with thetendency to restore the horizontal orientationof tibial plateau Various supportive mechanismscan be facilitating perfect spinning of femoralcondyles on the tibial plateau not only in favorof protecting the knee from injuries but also infavor of this force couple mechanics on femurApart from executing postural control the CKCankle dorsiflexion during squat may possessmultiple biomechanical advantages by tilting thetibia and tibial plateau anteriorly Anteriorinclination of tibial plateau can also facilitatethe required anterior gliding of femoral condyleto reduce the stress in anterior cruciate ligament(ACL) during initial stages of flexion of knee inCKC Hamstrings activity has been linked withreducing stress on ACL and its peak activity wasfound to occur anywhere between 10deg and 70degof knee flexion11 So the anterior inclination oftibial plateau and Hamstrings activity maytogether play a vital role to safeguard ACLespecially when the Quadriceps activity tendsto peak Peak activity of Quadriceps has beennoted at approximately 80deg to 90deg of kneeflexion9 Any excess anterior gliding of femoralcondyle can also be retarded by patella toprevent elevation of the stress in posteriorcruciate ligament (PCL) or by PCL to preventelevation of patellofemoral joint reaction forces(Figure 6a6b) Shields et al studying theco-contraction between the Quadriceps and theHamstrings in the squat exercise in three loadlevels have verified that the activity of theQuadriceps muscle was higher than theHamstrings for all levels12 PCL forces whichwere generated throughout the squat descentand ascent progressively increased as the kneesflexed and decreased as the knees extended13

Controlled dorsiflexion caused by Soleus can beanother supportive system to neutralize theanterior tibial translation effects of QuadricepsThe Soleus muscle slows down the ankledorsiflexion and creates a knee extensiontorque forcing the tibia backwards which

minimizes the anterior shear force in the kneejoint14 Posterior tibiofemoral shear force on ACL-intact knees indicated that the potential loadingon the injured or reconstructed anterior cruciateligament is not significant and also themagnitude of the posterior tibiofemoral shearforce is not likely to be detrimental to the injuredor reconstructed posterior cruciate ligament15

Deep squats and activities with deep kneeflexions (Photograph - 1 amp 2) could demandgreater magnitude of angular displacement offemur and the total work output from FCM onfemur Knee structures are highly constrained atangles greater than 120deg resulting in much lessanterior and posterior tibial translation and tibialrotation in comparison with lesser flexionangles16 Dislocating effect on the knee causedby compression of posterior thigh and calfmuscles has been one of the concerns of deepsquat according to Kreighbaum et al17 In deepknee flexion angles the ACL and PCL can almostget aligned horizontally and verticallyrespectively through which the dislocatingeffects on the knee caused by compression ofposterior thigh and calf muscles may getprevented However failure to control the squatdescent can result in the ballistic contactbetween the hamstrings and calf muscles whichcan cause a dislocating effect on the kneeligaments18 Hence when all such protectivemechanisms work in perfect balance the axisat knee joint can remain stable to effectivelysupport the FCM on femurPhotograph 1 Deep squat Photograph 2 Climbing up

high platform

The major biomechanical challenge during CKCactivities of lower extremities is to move thetrunk in the purposeful directions oftenassociated with purposeful activities of upper

Int J Physiother Res 20142(6)766-71 ISSN 2321-1822 770

R V inodh Rajkumar FORCE COUPLE MECHANICS ON FEMUR DURING CLOSED KINETIC CHAIN ACTIVITIES OF LOWER LIMBS

extremities for which spinal stability is vitalStability of spine is determined by activationlevels of all trunk muscles regardless of themagnitude of Intra-abdominal pressure (IAP) andthe effectiveness of IAP becomes mosteffective at stabilizing the spine when appliedin concert with co-activation of the Erectorspinae muscles19 Any increased hoop tensioncreated by the Transversus abdominus andInternal oblique abdominal muscles would serveto not only increase IAP but it would alsoincrease segmental joint stiffness and serve tostabilize the spine in all planes of motion20 Butthe recruitment of trunk muscles may dependon the mechanisms that ensure stability ofpelvis and knee joint to support the FCM onfemur For example the abdominal musclesshould enhance the stability of lumbar spinewhile Iliopsoas contracts to provide workingfoundation for Gluteus maximus during FCM onfemur

CONCLUSION

From biomechanical perspective a wide rangeof CKC activities of lower extremities thatincorporates knee flexion and ankle dorsiflex-ion irrespective of the magnitude of range ofmotion may be inevitably relying on this forcecouple muscular system on femur howeverelectromyographic studies on the basis of thisconcept is warranted to dig out relevant scien-tific data This concept of FCM on femur and itsrelated supportive biomechanics can also be partof the future research efforts in the field ofPhysical therapy rehabilitation and fitnesstraining to further enhance the understandingof biomechanics of CKC activities like stairclimbing squats lunges bent-knee dead liftsjumps and all other locomotion

Conflicts of interest None

REFERENCES

3 De Leva P Adjustments to Zatsiorsky-SeluyanovrsquosSegment Inertia Parameters Journal ofBiomechanics 199629(9)1223-1230

4 Plagenhoef S Evans FG Abdelnour T Anatomicaldata for analyzing human motion ResearchQuarterly for Exercise and Sport 198354169-178

5 Pearsall DJ Reid JG The study of human bodysegment parameters in biomechanics An historicalreview and current status report Sports Med 1994Aug18(2)126-40

6 Mike Decker Jake Krong Dan Peterson Tyler AnstettMichael Torry Erik Giphart Kevin ShelburneMarcPhilippon Deep hip muscle activation during asquat exercise Retrieved from httpwwwasbweborgconferences2009943pdf

7 Cheron G Bengoetxea A Pozzo T Bourgeois M DrayeJP Evidence of a preprogrammed deactivation ofthe hamstring muscles for triggering rapid changesof posture in humans Electroenceph ClinNeurophysiol 199710558ndash71

8 Valdeci Carlos Dionisio Gil Lucio Almeida MarcosDuarte Rogerio Pessoto Hirata Kinematic Kineticand EMG patterns during downward squattingJournal of Electromyography and Kinesiology200818134-143

9 Escamilla RF Knee biomechanics of the dynamicsquat exercise Med Sci Sports Exerc 200133127ndash141 2001

10 Yasuda K and T Sasaki Exercise after anteriorcruciate ligament reconstruction the force exertedon the tibia by the separate isometric contractionsof the quadriceps or the hamstringsClinOrthop1987 220275ndash283

11 Senter C Hame SL Biomechanical analysis of tibialtorque and knee flexion angle Implications forunderstanding knee injury Sports Med200636635ndash641

12 Shields RK Madhavan S Gregg E Leitch J PetersenB Salata S et al Neuromuscular control of the kneeduring a resisted single-limb squat exercise Am JSports Med 2005331520-6

13 Toutoungi DE TWLu A Leardini F Catani and JJOrsquoConnor Cruciate ligament forces in the humanknee during rehabilitation exercises Clin Biomech200015176 ndash187

14 Elias JJ Faust AF Chu Y Chao EY Cosgarea AJ Thesoleus muscle acts as an agonist for the anteriorcruciate ligament an in vitro experimental studyAm J Sports Med 200331241-6

15 Stuart MJ Meglan DA Lutz GE Growney ES An KNComparison of intersegmental tibiofemoral jointforces and muscle activity during various closedkinetic chain exercises Am J Sports Med 1996 Nov-Dec24(6)792-9

16 Li G DeFrate LE Rubash HE and Gill TJ In vivokinematics of the ACL during weight bearing kneeflexion J Orthop Res 200523340-344

17 Kreighbaum E Katharine BM Biomechanics AQualitative Approach for Studying HumanMovement Allyn amp Bacon 1996Pgs 203-204

1 Caterisano A Moss RF Pellinger TK Woodruff KLewis VC Booth W Khadra T The effect of backsquat depth on the EMG activity of 4 superficialhip and thigh muscles J Strength Cond Res Aug2002 16(3) 428-32

2 Escamilla RF Fleisig GS Zheng N Barrentine SWWilk KE Andrews JR Biomechanics of the kneeduring closed kinetic and open kinetic chainexercises Med Sci Sport Exerc 199830556-69

Int J Physiother Res 20142(6)766-71 ISSN 2321-1822 770

R V inodh Rajkumar FORCE COUPLE MECHANICS ON FEMUR DURING CLOSED KINETIC CHAIN ACTIVITIES OF LOWER LIMBS

extremities for which spinal stability is vitalStability of spine is determined by activationlevels of all trunk muscles regardless of themagnitude of Intra-abdominal pressure (IAP) andthe effectiveness of IAP becomes mosteffective at stabilizing the spine when appliedin concert with co-activation of the Erectorspinae muscles19 Any increased hoop tensioncreated by the Transversus abdominus andInternal oblique abdominal muscles would serveto not only increase IAP but it would alsoincrease segmental joint stiffness and serve tostabilize the spine in all planes of motion20 Butthe recruitment of trunk muscles may dependon the mechanisms that ensure stability ofpelvis and knee joint to support the FCM onfemur For example the abdominal musclesshould enhance the stability of lumbar spinewhile Iliopsoas contracts to provide workingfoundation for Gluteus maximus during FCM onfemur

CONCLUSION

From biomechanical perspective a wide rangeof CKC activities of lower extremities thatincorporates knee flexion and ankle dorsiflex-ion irrespective of the magnitude of range ofmotion may be inevitably relying on this forcecouple muscular system on femur howeverelectromyographic studies on the basis of thisconcept is warranted to dig out relevant scien-tific data This concept of FCM on femur and itsrelated supportive biomechanics can also be partof the future research efforts in the field ofPhysical therapy rehabilitation and fitnesstraining to further enhance the understandingof biomechanics of CKC activities like stairclimbing squats lunges bent-knee dead liftsjumps and all other locomotion

Conflicts of interest None

REFERENCES

3 De Leva P Adjustments to Zatsiorsky-SeluyanovrsquosSegment Inertia Parameters Journal ofBiomechanics 199629(9)1223-1230

4 Plagenhoef S Evans FG Abdelnour T Anatomicaldata for analyzing human motion ResearchQuarterly for Exercise and Sport 198354169-178

5 Pearsall DJ Reid JG The study of human bodysegment parameters in biomechanics An historicalreview and current status report Sports Med 1994Aug18(2)126-40

6 Mike Decker Jake Krong Dan Peterson Tyler AnstettMichael Torry Erik Giphart Kevin ShelburneMarcPhilippon Deep hip muscle activation during asquat exercise Retrieved from httpwwwasbweborgconferences2009943pdf

7 Cheron G Bengoetxea A Pozzo T Bourgeois M DrayeJP Evidence of a preprogrammed deactivation ofthe hamstring muscles for triggering rapid changesof posture in humans Electroenceph ClinNeurophysiol 199710558ndash71

8 Valdeci Carlos Dionisio Gil Lucio Almeida MarcosDuarte Rogerio Pessoto Hirata Kinematic Kineticand EMG patterns during downward squattingJournal of Electromyography and Kinesiology200818134-143

9 Escamilla RF Knee biomechanics of the dynamicsquat exercise Med Sci Sports Exerc 200133127ndash141 2001

10 Yasuda K and T Sasaki Exercise after anteriorcruciate ligament reconstruction the force exertedon the tibia by the separate isometric contractionsof the quadriceps or the hamstringsClinOrthop1987 220275ndash283

11 Senter C Hame SL Biomechanical analysis of tibialtorque and knee flexion angle Implications forunderstanding knee injury Sports Med200636635ndash641

12 Shields RK Madhavan S Gregg E Leitch J PetersenB Salata S et al Neuromuscular control of the kneeduring a resisted single-limb squat exercise Am JSports Med 2005331520-6

13 Toutoungi DE TWLu A Leardini F Catani and JJOrsquoConnor Cruciate ligament forces in the humanknee during rehabilitation exercises Clin Biomech200015176 ndash187

14 Elias JJ Faust AF Chu Y Chao EY Cosgarea AJ Thesoleus muscle acts as an agonist for the anteriorcruciate ligament an in vitro experimental studyAm J Sports Med 200331241-6

15 Stuart MJ Meglan DA Lutz GE Growney ES An KNComparison of intersegmental tibiofemoral jointforces and muscle activity during various closedkinetic chain exercises Am J Sports Med 1996 Nov-Dec24(6)792-9

16 Li G DeFrate LE Rubash HE and Gill TJ In vivokinematics of the ACL during weight bearing kneeflexion J Orthop Res 200523340-344

17 Kreighbaum E Katharine BM Biomechanics AQualitative Approach for Studying HumanMovement Allyn amp Bacon 1996Pgs 203-204

1 Caterisano A Moss RF Pellinger TK Woodruff KLewis VC Booth W Khadra T The effect of backsquat depth on the EMG activity of 4 superficialhip and thigh muscles J Strength Cond Res Aug2002 16(3) 428-32

2 Escamilla RF Fleisig GS Zheng N Barrentine SWWilk KE Andrews JR Biomechanics of the kneeduring closed kinetic and open kinetic chainexercises Med Sci Sport Exerc 199830556-69

Int J Physiother Res 20142(6)766-71 ISSN 2321-1822 771

18 Donnelly DV Berg WP and Fiske DM The effect ofthe direction of gaze on the kinematics of the squatexercise J Strength Cond Res 200620145ndash150

19 Cholewicki J Juluru K McGill S Intra-abdominalPressure Mechanism for Stabilizing the LumbarSpine Journal of Biomechanics 19993213-17

20 Richardson C Jull G Hodges P and Hides JTherapeutic Exercise For Spinal SegmentalStabilization In Low Back Pain - Scientific BasisAnd Clinical Approach London New YorkPhi l idelphia Sydney Toronto Churchil lLivingstone1999 6 p 55-58

How to cite this articleR Vinodh Rajkumar FORCE COUPLE MECHANICS ON FEMUR DURINGCLOSED KINETIC CHAIN ACTIVITIES OF LOWER LIMBS Int J Physiother Res20142(6)766-771 DOI 1016965ijpr2014689

R V inodh Rajkumar FORCE COUPLE MECHANICS ON FEMUR DURING CLOSED KINETIC CHAIN ACTIVITIES OF LOWER LIMBS