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All,
For the past twelve months I have been working closely with my local running store. They are very knowledgeable (all staff being experienced marathon runners) and have been helpful in my education. One of the things they talk about is the "drive leg"; that is they consider that power is mainly provided by one leg, viz the drive leg and that the other leg is, in the main, "along for the ride". They equate this with the dominant side i.e. the persons "handedness". Given the number of discussion we've had in the past on the Jiscmail forum re: pushing and pulling, & the contralateral power generation described by spinal engine theory, I wondered if anyone else was familiar with this concept and invite your views. I know Kevin is an experienced runner who sometimes goes into hallucinogenic states whilst participating in this activity (its was a pig! ) Anyone else?
__________________ Science is the antidote to the poison of enthusiasm and superstition
All,
For the past twelve months I have been working closely with my local running store. They are very knowledgeable (all staff being experienced marathon runners) and have been helpful in my education. One of the things they talk about is the "drive leg"; that is they consider that power is mainly provided by one leg, viz the drive leg and that the other leg is, in the main, "along for the ride". They equate this with the dominant side i.e. the persons "handedness". Given the number of discussion we've had in the past on the Jiscmail forum re: pushing and pulling, & the contralateral power generation described by spinal engine theory, I wondered if anyone else was familiar with this concept and invite your views. I know Kevin is an experienced runner who sometimes goes into hallucinogenic states whilst participating in this activity (its was a pig! ) Anyone else?
I would say that the running store sales people you are dealing with, Simon, are wrong unless they qualified their ideas by proposing that there may be slight differences in the kinetics of the two legs during running. However, in well-trained and efficient runners, there is minimal asymmetry in kinetics and kinematics between the two lower limbs in running. By the way, it wasn't a pig after all.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
Kevin's right --- symmetry is more apparent in elite vs non-elite runners
__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________ God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University This is where I am, where are you?
Kevin's right --- symmetry is more apparent in elite vs non-elite runners
Given that the majority of runners aren't elite athletes, we can only deduce from your statement above that the majority of runners do show asymmetry in the lower limb kinetics/ kinematics and thus the drive leg theory may well be correct in this majority? Do we see greater joint moments in the dominant side or contra-dominant side in such individuals?
__________________ Science is the antidote to the poison of enthusiasm and superstition
Sort of --- i do recall a study that did look at symmetry in elite vs non-elite and there was less symmetry in the non-elite group .. if I recall correctly, they did not call it asymetrical, but 'less symetrical'.
Dominant vs non-dominant side is an interesting debate and I looked into the literature on this a while back. It obvious which is the dominant hand -- which hand do you prefer to write with? BUT (and this surprised me) there is far from being a consensus in the literature on how to determine the dominant leg. Is it the leg you prefer to kick a ball with or is it the leg you balance on when you kick a ball? ... for the purposes of our study, I stayed away from the dominant/non-dominant issue and uses 'limb they prefer to kick a ball with" .... did not matter anyway, as we found nothing.
__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________ God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University This is where I am, where are you?
Last edited by Admin : 2nd February 2006 at 04:37 PM.
Reason: typo
when kicking a ball the stance leg is the non-dominant.......same as pushing off riding a bicycle the push-off leg (the one on the pedal not on the ground) is the dominant.........so says my p/t mate
Given that the majority of runners aren't elite athletes, we can only deduce from your statement above that the majority of runners do show asymmetry in the lower limb kinetics/ kinematics and thus the drive leg theory may well be correct in this majority? Do we see greater joint moments in the dominant side or contra-dominant side in such individuals?
Beginning runners will have all sorts of odd gait patterns due to mechanical asymmetries and a lack of central nervous system coordination. As the mileage base increases, so does central nervous system coordination improve. The more mechanically efficient runners will generally continue to improve in efficiency and the mechanically inefficient runners will generally quit due to injury. This happens a lot in children so that the high schoolers that are on the cross-country team or soccer team are generally those individuals with skeletal alignment that will minimize injury risk and improve running efficiency and speed.
If we are talking about experienced marathon runners (not elite marathoners that run under 2:15), then in these individuals the gait symmetry is fairly good. The idea of a dominant or drive limb is not what I have seen or experienced myself in over 30 years of competitive running and have not seen this anywhere in the scientific literature on running. However, in beginners, especially those with widely asymmetrical skeletal structure or muscle stength, the idea of a dominant limb may be something that is fairly substantial. However, I don't call these people runners....they are joggers. Sorry, it is hard for me to not be a running snob considering my long history of long distance running competition.
However, I do enjoy discussing the biomechanics of running for a change.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
when kicking a ball the stance leg is the non-dominant.......same as pushing off riding a bicycle the push-off leg (the one on the pedal not on the ground) is the dominant.........so says my p/t mate
If you delve into the dominance/non-dominant literature, there appears to be no consensus on which limb is "dominant" ... I originally assumed it to be the one that a ball is kicked with.
__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________ God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University This is where I am, where are you?
If you delve into the dominance/non-dominant literature, there appears to be no consensus on which limb is "dominant" ... I originally assumed it to be the one that a ball is kicked with.
While multi-tasking I frequently type on the computer with my foot (as I am doing now). I always use my right foot, which is the same foot that I kick a ball, push off on a bike with, and suture lacerations as I fill out the billing slip with my hands. When I try to type withh my leeft fot(as I amn doingh nows)( imake manyh mistkes,
Beginning runners will have all sorts of odd gait patterns due to mechanical asymmetries and a lack of central nervous system coordination. As the mileage base increases, so does central nervous system coordination improve. The more mechanically efficient runners will generally continue to improve in efficiency and the mechanically inefficient runners will generally quit due to injury. This happens a lot in children so that the high schoolers that are on the cross-country team or soccer team are generally those individuals with skeletal alignment that will minimize injury risk and improve running efficiency and speed.
If we are talking about experienced marathon runners (not elite marathoners that run under 2:15), then in these individuals the gait symmetry is fairly good. The idea of a dominant or drive limb is not what I have seen or experienced myself in over 30 years of competitive running and have not seen this anywhere in the scientific literature on running. However, in beginners, especially those with widely asymmetrical skeletal structure or muscle stength, the idea of a dominant limb may be something that is fairly substantial. However, I don't call these people runners....they are joggers. Sorry, it is hard for me to not be a running snob considering my long history of long distance running competition.
However, I do enjoy discussing the biomechanics of running for a change.
What are you thoughts on there being just as much structural/skeletal asymmetry in elite athletes but much better strength patterns which prevent fatigue leading to less observable imbalances?
This then leads to the question on better CNS control, not just co-ordination, but less fatigue at CNS level? Greater efficiency from specific training, better fuel utilisation, better absorption rates of fuel, better fluid/nutrient replacement through race? This combined with their more efficient physiological variables which we can see in testing such as power output vs thresholds etc result in less observable gait asymmetry than a 3.5 hour marathon runner.
I also think the terminology used initially in this discussion makes things sound grossly imbalanced. Dominant leg, along for the free ride etc. When in reality there is probably not that much visible difference but a greater perceptual ability in an elite level athlete than someone who is just aiming to breath hard enough to maintain their run. Let alone worry about their symmetry and which side feels more efficient or dominant.
What are you thoughts on there being just as much structural/skeletal asymmetry in elite athletes but much better strength patterns which prevent fatigue leading to less observable imbalances?
This then leads to the question on better CNS control, not just co-ordination, but less fatigue at CNS level? Greater efficiency from specific training, better fuel utilisation, better absorption rates of fuel, better fluid/nutrient replacement through race? This combined with their more efficient physiological variables which we can see in testing such as power output vs thresholds etc result in less observable gait asymmetry than a 3.5 hour marathon runner.
Before I matriculated to podiatry school, I took all the undergraduate and a few graduate courses in exercise physiology at UC Davis, thinking that this may be a eventual career path for me. I chose podiatry instead.
My observations and studies in exercise physiology and biomechanics has led me to the conclusion that elite athletes have not only better genetic skeletal structure and muscle type for their specific sport, but also a personality type that allows them to endure the rigors of incessant training and competitive athletics.
Fatigue is still hard to quantify and the researchers still don't know as much about it from a cellular level as they would like to. However, in general, the central nervous system (CNS) will develop improved coordination with the repetetive accomplishments of the same activity. Elite athletes also have a high level of CNS coordination for their specific sport. In endurance athletes, there are many physiological adaptations that may affect performance with increased training and fitness such as a higher maximal oxygen uptake, higher lactate threshold, improved extraction of oxygen from atmosphere, higher density of mitochondria in cells, more efficient utilization of fat as energy source, increased tendon, bone and muscle strength, increased blood volume, increased cardiac output, increased lean body mass, etc.
From my experiences and observations of competing against sub-elite and elite athletes in college,there is insignificant gait asymmetry in these individuals during running. They are almost all very symmetrical in their smoothness of gait with their strides seeming to be "effortless" to the casual observer. Of course, you have exceptions such as the contorted, grimacing style of Emil Zatopek, but that is not the norm in elite runners.
Certainly becoming an elite runner may be a strength issue but is more likely a combination of muscle strength, muscle endurance, skeletal structure and CNS coordination, to name a few parameters. It is a fascinating subject and has been researched with great intensity over the past 30 or more years. Most podiatrists have very little knowledge of this subject which I think is a shame since it is very important for recommending proper training advice for athletic patients.
Quote:
I also think the terminology used initially in this discussion makes things sound grossly imbalanced. Dominant leg, along for the free ride etc. When in reality there is probably not that much visible difference but a greater perceptual ability in an elite level athlete than someone who is just aiming to breath hard enough to maintain their run. Let alone worry about their symmetry and which side feels more efficient or dominant.
I agree. It's hard for me to imagine a group of seasoned and intelligent marathon runners discussing "dominant legs" or "leg is along for a free ride", unless they were just guessing about something they read about in a running magazine. Of course, there is so much misinformation about shoes and training styles in many running shoe stores that I suppose anything is possible.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
There was an asymmetry study published last year that looked at the shape of athletes earlobes and their performance. The asymmetry of the earlobes was supposed to reflect a general increased asymmetry in their body. This asymmetry would then contribute to greater imbalance and reduced efficiency and so lower performance. I believe they proved statistical relevance.
As an owner of a running store, coach and past sub-elite athlete I have never heard of the "drive leg" and would be very surprised if it existed in greater than 1% of the population to any significant extent. Force plate studies would have easily identified this in the past and runners footwear would have significantly different wear patterns. As this only occurs in a minority of patients I would say that it reflects a pathomechanical situation that needs gait modification and not a general finding.
When doing a 'non-treadmill' video gait analysis you can measure the number of frames per step as well as the distance per step and see if there is a difference. That along with a comparison of the joint ROM of each leg will identify if asymmetry exists between legs.
I do not think that the dominant 'kicking foot' analogy is relevant as it relates more to coordination then power and while a runner may prefer to step up a curb with a particular foot, on the flat the power would be similar.
Finally Kevin, whether a runner or jogger is a state of mind separate from speed or experience.
Last edited by Steve The Footman : 3rd February 2006 at 09:48 PM.
Reason: spelling error
Finally Kevin, whether a runner or jogger is a state of mind separate from speed or experience.
If you would like to believe this, Steve, then you have a right to your own opinion. However, as far as I'm concerned, someone who, in their mind, thinks they are a runner by doing 12 minute miles is still a jogger to me (and also is a jogger to the vast majority of competetive runners that I have associated with over the past 30+ years). This is no different from all the people competing on "American Idol" who think they can sing when, instead, their voice sounds to me like fingernails being scratched on a blackboard. It's all a matter of self-perception versus objectivity......which ever one you prefer to believe is real is totally up to you.
Definition: Jog: to run at a leisurely, slow pace, esp. as an outdoor exercise.
(Webster's Encyclopedic Unabridged Dictionary of the English Language, Random House Value Publishing, Inc, 2001).
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
someone who, in their mind, thinks they are a runner by doing 12 minute miles is still a jogger to me
Lets see 12 / 1.6 = 7.5 min/km x 42.2 =5:16 marathon
Can not argue with the logic of that. I forgot that in the U.S. the average time for a marathon is almost 4:30. In Australia we would not get 10% slower than that. When a normal person can walk at the pace someone else runs then perhaps jogging is a more appropriate term.
However my contention of mindset being important is still valid. Some people can run a 60 minute 10km with little training and see themselves as 'joggers' while other less talented runners train hard with speedwork and consistency and run the same time but consider themselves 'runners'.
Sorry about the hijack everyone. I have a tape measure that I use to compare calf circumference if there is an obvious difference visually. In these patients you would expect that asyymetrical calf hypertrophy would be a result of asymmetrical workload.
came across this article....Journal of Athletic Training 2005;40(3):203–206........in which "Conclusions: Hip-abduction strength differences exist between the dominant and nondominant legs..............Side-to-side strength imbalances exist between the hip abductors of asymptomatic healthy individuals."
.............also anecdotal reports, my favourite is, apparently if ask blindfolded participant, who is stood under goalposts at one end of a field and is aligned facing the other end, to walk to that other end of the field, most will traverse a curved path towards their non-dominant leg side, a phenomenon well known to trackers (apparently most lost people follow a anti-clockwise curved path)... i thought it was interesting....not sure how relevant it is though
I was just doing a lit search for something else and came across this ref:
Quote:
Comparison of muscle strength and flexibility between the preferred and non-preferred leg in English soccer players.
Ergonomics. 2005 Sep 15-Nov 15;48(11-14):1568-75.
Rahnama N, Lees A, Bambaecichi E.
Most soccer players have a favoured foot for kicking the ball, and it is believed that this preference may lead to an asymmetry in the strength and flexibility of the lower extremities. This study was designed to determine whether asymmetry in strength and flexibility are present in the legs of soccer players.Forty-one elite and sub-elite soccer players (age 23.4 +/- 3.8 years; height 1.81 +/- 0.06 m; body mass 81.7 +/- 9.9 kg) were studied (data are presented as mean +/- SD). The dynamic strength of knee flexors (hamstrings) and knee extensors (quadriceps) was measured using an isokinetic dynamometer at angular velocities of 1.05, 2.09, 5.23 rad/s (in a concentric mode) and 2.09 rad/s (in an eccentric mode). The concentric strength ratio (hamstrings(conc)/quadriceps(conc)) and the dynamic control ratio (hamstrings(ecc)/quadriceps(conc)) were computed. Hip joint flexibility (in flexion) was measured using a goniometer.A significant difference between the preferred and non-preferred leg was found in the knee flexors at 2.09 rad/s (119 +/- 22 versus 126 +/- 24 Nm; P < 0.05) and for the dynamic control ratio (0.79 +/- 0.13 versus 0.84 +/- 0.16 Nm; P < 0.05). In both cases the knee flexors of the preferred leg were weaker than those of the non-preferred leg. A total of 28 of the 41 players (68%) had significant musculoskeletal abnormality (imbalance >10%) in one or more specific muscle groups. No significant differences were found in flexibility of the hip joint between the preferred and non-preferred leg (P > 0.05).It is concluded that the lower strength of the knee flexor muscles of the preferred leg may be associated with the differential use of these muscle during the kicking action and thus constitutes a unique training effect associated with soccer. This in turn can lead to muscular imbalance which is generally regarded as an injury risk factor.
Notice they use prefered/non-prefered kicking leg as opposed to dominant/non-dominant.
__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________ God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University This is where I am, where are you?
in a brief PubMed search in some of the literature it claims that in bipedal "asymmetrical" tasks eg. kick a ball, where there is a stabilising task and a mobilising task (not bipedal "symmetrical" tasks eg. what elite athletes do) there is a "dominant leg FOR STABILISATION and a dominant leg FOR MOBILISATION"..........in a few articles the term "footedness" was used for the "preferred leg".........as craig P mentions the neuro biologists/psychologists seem reluctant to assign "dominance" without further study, mark c
Detailed time-series of the resultant joint moments and segmental interactions during soccer instep kicking were compared between the preferred and non-preferred kicking leg. The kicking motions of both legs were captured for five highly skilled players using a three-dimensional cinematographic technique at 200 Hz. The resultant joint moment (muscle moment) and moment due to segmental interactions (interaction moment) were computed using a two-link kinetic chain model composed of the thigh and lower leg (including shank and foot). The mechanical functioning of the muscle and interaction moments during kicking were clearly illustrated. Significantly greater ball velocity (32.1 vs. 27.1 m . s(-1)), shank angular velocity (39.4 vs. 31.8 rad . s(-1)) and final foot velocity (22.7 vs. 19.6 m . s(-1)) were observed for the preferred leg. The preferred leg showed a significantly greater knee muscle moment (129.9 N . m) than the non-preferred leg (93.5 N . m), while no substantial differences were found for the interaction moment between the two legs (79.3 vs. 55.7 N . m). These results indicate that the highly skilled soccer players achieved a well-coordinated inter-segmental motion for both the preferred and non-preferred leg. The faster leg swing observed for the preferred leg was most likely the result of the larger muscle moment.
Healthy men (n = 42) and women (n = 45) who were right-handed and men (n = 21) and women (n = 20) who were left-handed were studied. Men's mean age was 21.1 +/- 3.5 yr. and women's 20.7 +/- 3.1 yr. These students in various faculties reported they were right- or left-handed. Then their hand and foot preferences (handedness and footedness) were ascertained by asking each of the subjects to perform 11 tasks for handedness and 9 tasks for footedness. A discriminate function analysis test showed that each of the 11 tasks used for assessing their self-reported handedness was significant, but, of the 9 tasks used for assessing self-reported footedness, only 7 were significant. Strength of the hand or foot played no role in reports of handedness or footedness. A combination of four tasks, such as pulling a door, pushing a door, holding an object, and hammering a nail, on which the maximum number of subjects performed with the right or left hand, depending upon their self-reported handedness, would be ideal for ascertaining handedness. A combination of three tasks, namely, kicking a football, pushing an object with the foot, and stamping on the ground, would be ideal for ascertaining footedness.
I know this is a very old thread ... but came across the new abstract below and it reminded me of this thread. Apparently limb dominance is an issue for birds as well: Foot preferences during resting in wildfowl and waders. Laterality. 2007 Mar;12(2):191-7
Quote:
Footedness in birds has been reported, e.g., in parrots and chickens, but the direction of footedness remained unclear. Is a bird left-footed because it uses its left foot for holding and handling food, or is it right-footed because it uses the right foot for stabilisation and balancing while perching? In 2004 and 2006 I examined footedness in wildfowl and waders while the birds were performing a single task: roosting on the ground on one foot. Avocet (Recurvirostra avosetta), northern shoveller (Anas clypeata), oystercatcher (Haematopus ostralegus), and Eurasian curlew (Numenius arquata) were right-footed. Another 21 species did not show any significant foot preferences. This study provides some evidence that asymmetries in preferential foot use in birds may be triggered by a preference during postural control.
How do they get funding for this sort of research when clinical podiatric research (which actually can help people get better) struggles?
Driving leg and other leg along for the ride, sounds to me if that was the case running could be undertaken with only the one leg, I think that's called hopping?
For what it's worth I undertook gymnastics at an elite level and soccer as did my sister, everytime any tumbling, cartwheel etc the preferred leg was the lead leg this was also our kicking leg in soccer.
I know this is a very old thread ... but came across the new abstract below and it reminded me of this thread. Apparently limb dominance is an issue for birds as well: Foot preferences during resting in wildfowl and waders. Laterality. 2007 Mar;12(2):191-7
Footedness in birds has been reported, e.g., in parrots and chickens, but the direction of footedness remained unclear. Is a bird left-footed because it uses its left foot for holding and handling food, or is it right-footed because it uses the right foot for stabilisation and balancing while perching? In 2004 and 2006 I examined footedness in wildfowl and waders while the birds were performing a single task: roosting on the ground on one foot. Avocet (Recurvirostra avosetta), northern shoveller (Anas clypeata), oystercatcher (Haematopus ostralegus), and Eurasian curlew (Numenius arquata) were right-footed. Another 21 species did not show any significant foot preferences. This study provides some evidence that asymmetries in preferential foot use in birds may be triggered by a preference during postural control.
How do they get funding for this sort of research when clinical podiatric research (which actually can help people get better) struggles?
I can see it now. A guy in a camp chair with a foot rest and a drink in his drink holder and a pair of binoculras sitting at the edge of a lake at sunset....
Craig, Perhaps you should submit your research proposals to the Audobon society. The guy who did the bird research probably got plantar fasciitis walking to the lake carrying his chair, clipboard and binoculars.
The answer to the drive leg issue can be solved by using inverse dynamics and looking at the joint power (angular velocity x joint moment). You still need a source of energy to make the back leg become the front leg regardless if it is dominent or not.
The answer to the drive leg issue can be solved by using inverse dynamics and looking at the joint power (angular velocity x joint moment). You still need a source of energy to make the back leg become the front leg regardless if it is dominent or not.
Just to follow on from that thought can one leg be more dominant than the other? If one leg is weak then it cannot produce enough power to drive the contralateral side as far forward as the strong leg can. Therefore there might be a short stride length on the strong side. In which case if there is asymmetry then the weak side must have a long stride therfore it must be stronger in power absorption?? Therefore one leg is a strong power producer and the other a strong power retarder. EH!
I have only thought about that for five minutes so it may be rediculous but I thought I would throw it in the ring.
Just to follow on from that thought can one leg be more dominant than the other? If one leg is weak then it cannot produce enough power to drive the contralateral side as far forward as the strong leg can. Therefore there might be a short stride length on the strong side. In which case if there is asymmetry then the weak side must have a long stride therfore it must be stronger in power absorption?? Therefore one leg is a strong power producer and the other a strong power retarder. EH!
I have only thought about that for five minutes so it may be rediculous but I thought I would throw it in the ring.
Cheers Dave
Walking is making the back leg become the front leg repetedly. Moving a leg takes energy. Energy input can come from hip pull or ankle push. If a leg is weak there will be more hip pull. There is an equal and opposite reaction at the initiation of swing phase with hip pull. The trunk pulls the leg forward and leg pulls the trunk back. Or in terms of energy the trunk looses kinetic energy to the leg at the initiation of swing and the energy is returned at the completion of swing phase.
Certainly asymmetry is possible. One leg can have more ankle push than the other. You can choose to have a silly walk. (who holds the position of silly walks now?:) )
Leg kinematics and kinetics in landing from a single-leg hop for distance. A comparison between dominant and non-dominant leg
J.J. van der Harsta, A. Gokelerb, A.L. Hofab Clinical Biomechanics (Article in Press)
Quote:
Background
Anterior cruciate ligament (ACL) deficiency can be a major problem for athletes and subsequent reconstruction of the ACL may be indicated if a conservative regimen has failed. After ACL reconstruction signs of abnormality in the use of the leg remain for a long time. It is expected that the landing after a single-leg hop for distance (horizontal hop) might give insight in the differences in kinematics and kinetics between uninjured legs and ACL-reconstructed legs. Before the ACL-reconstructed leg can be compared with the contralateral leg, knowledge of differences between legs of uninjured subjects is needed.
Methods
Kinematic and kinetic variables of both legs were measured with an optoelectronic system and a force plate and calculated by inverse dynamics. The dominant leg (the leg with biggest horizontal hop distance) and the contralateral leg of nine uninjured subjects were compared.
Findings No significant differences were found in most of the kinematic and kinetic variables between dominant leg and contralateral leg of uninjured subjects. Only hop distance and hip extension angles differed significantly.
Interpretation
This study suggests that there are no important differences between dominant leg and contralateral leg in healthy subjects. As a consequence, the uninvolved leg of ACL-reconstructed patients can be used as a reference. The observed variables of this study can be used as a reference of normal values and normal differences between legs in healthy subjects.
Strength of leg preference and interlateral asymmetry in kinematics of kicking a ball for power were assessed in 6- to 10-year-old right-footed soccer player children. Leg preference was evaluated separately for three task categories: balance stabilization, soccer related mobilization, and general mobilization. The results showed that while both categories of mobilization tasks were featured by a consistent preference for the right leg, in stabilization tasks we observed lower scores and greater interindividual variability of leg preference. No effect of age was detected on leg preference. Analysis of peak foot velocity revealed similar increment of performance of the right and left legs from the ages 6-8 to 10 years. This finding supports the notion of stable magnitude of interlateral asymmetries of performance during motor development
Drive leg
) Anyone else?
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