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This concept has popped up on my radar a bit recently, so I looked into it some more. This comment in the context of managing a runner with patellofemoral pain first got my attention:
Quote:
Address their running form....... Make sure they are at a proper cadence, 180 steps/minute. This is verified in literature to be a great injury reduction factor.
The poster in Mike Reinold's forum that stated that was challenged as to that "literature" and then quite rightly conceded that there is none, but i looked around and followed their links and it seems that this concept is gaining some legs.
Yet beginning and recreational runners typically have a cadence closer to 160, which Daniels* says puts them at risk for injury because the longer strides necessitated by a slower cadence take runners higher off the ground. This in turn means that each footfall is harder, and many running injuries are associated with the shock of landing. While Daniels can’t cite a study associating slow cadence with running injuries, I put a lot of weight on his experience coaching thousands of runners.
(*described by Runner's World as the "World's Best Running Coach" is known for his comprehensive research in sport performance and coaching of elite runners.). They obviously missed the evidence about how few running injuries are actually due to impact shock, but lets stay with it for now:
Quote:
Anecdotal evidence suggests that if your cadence is slower than 180 steps per minute, you might be able to reduce your risk of injury associated with landing shock by increasing your cadence.
Then there was this paper: Effects of step rate manipulation on joint mechanics during running.
Heiderscheit BC, Chumanov ES, Michalski MP, Wille CM, Ryan MB. Med Sci Sports Exerc. 2011 Feb;43(2):296-302.
Quote:
PURPOSE:
the objective of this study was to characterize the biomechanical effects of step rate modification during running on the hip, knee, and ankle joints so as to evaluate a potential strategy to reduce lower extremity loading and risk for injury.
METHODS:
three-dimensional kinematics and kinetics were recorded from 45 healthy recreational runners during treadmill running at constant speed under various step rate conditions (preferred, ± 5%, and ± 10%). We tested our primary hypothesis that a reduction in energy absorption by the lower extremity joints during the loading response would occur, primarily at the knee, when step rate was increased.
RESULTS:
less mechanical energy was absorbed at the knee (P < 0.01) during the +5% and +10% step rate conditions, whereas the hip (P < 0.01) absorbed less energy during the +10% condition only. All joints displayed substantially (P < 0.01) more energy absorption when preferred step rate was reduced by 10%. Step length (P < 0.01), center of mass vertical excursion (P < 0.01), braking impulse (P < 0.01), and peak knee flexion angle (P < 0.01) were observed to decrease with increasing step rate. When step rate was increased 10% above preferred, peak hip adduction angle (P < 0.01) and peak hip adduction (P < 0.01) and internal rotation (P < 0.01) moments were found to decrease.
CONCLUSION:
we conclude that subtle increases in step rate can substantially reduce the loading to the hip and knee joints during running and may prove beneficial in the prevention and treatment of common running-related injuries.
During a journal club where we discussed all of this, another PT stated that she thinks part of the reason this seems to help, especially with knee pain, is that the quicker cadence means less time on the ground and less time to fall into the really common overpronation-knee valgus-lower extremity internal rotation-contralateral hip drop, all of which have effects on the knee, hip and ankle. I have definitely seen this to be the case, as most people don't strike the ground in this pattern, but rather "fall" into it. Increasing cadence means they're not spending as much time on the ground, and thus don't have time to "fall" into this pattern. I have found that increasing cadence tends to put people at a little more of a midfoot pattern (which opens a whole other discussion), but it is a really easy training tool and I really think it prevents people from over thinking their gait mechanics, which is rather invaluable with Type A runners.
suggests that one way this can be achieved is by reducing stride length while maintaining the same speed. The only way to reduce stride length at a constant speed is to increase cadence, which is exactly what Daniels suggests.
..... but they do need a lesson in what science is!
In my frustration, I tried all kinds of ways to prevent injuries. Icing, running on softer surfaces, abstaining from speedwork, taking walk breaks, taking anti-inflammatories, changing my shoes, stretching religiously before and after every workout, walking around on my heels, even shaving my lower legs so I could tape them (really). The list goes on. Some of it seemed to help a little, but none of it solved my problem.
Until I discovered the answer. I read a piece by running coach Jack Daniels, where he wrote that most of the world's best marathoners have a leg turnover rate of about 180 steps per minute.
They also offered some advice on how to shorten the stride and increase the cadence to 180 steps/minute.
One of the basic principles of Pose running is a cadence of 180 steps/minute. The short choppy stride of Chi running would also be up around that as well!
I found this video from Newton Running Shoes on cadence: (ignore the bit that was made up about the braking action of heel striking)
I next consulted my bible on running, the Lore of Running by Tim Noakes ... there is no better evidence based review of running than this,....and he did not even mention it!
Of course, this doesn’t mean I don’t think stride rate is important. I definitely agree with those who suggest that overstriding is probably the most widespread and easily addressed problem among recreational runners. But rather than aspiring to a magical 180 threshold, I agree with Wisconsin researcher Bryan Heiderscheit, whose studies suggest that increasing your cadence by 5-10% (if you suspect you may be overstriding) is the way to go.
Some interesting discussion are followed that post.
Alex pretty much sums up my feelings on cadence, and I absolutely agree that 180 need not be some magic number that all runners need to shoot for
Quote:
ne often hears the magic number of 180 strides per minute thrown around these days as being the optimal cadence for a runner... I believe this number can be traced back to famed coach Dr. Jack Daniels observation that elite runners tend to run at a stride rate of 180-200 steps/minute. I’m not sure that we have any conclusive data saying that the 180 number is optimal for every person, but Heiderscheit et al. 2011 showed that running with a faster cadence/higher stride rate (5-10% increase) reduced loading on the knee and hip, allowed for a more level carriage of the center of mass (less vertical oscillation), shortened stride length, and created less braking impulse (read my post on the Heiderscheit paper here). All seem like reasonably positive outcomes if you ask me, and this paper might be a useful guide in that a mere 5% increase in you cadence might be all that is necessary to realize some benefit. It turns out that the 170-190 range would probably be where most people would land if they increased cadence by 5-10%.
He concluded that:
Quote:
I think perhaps the biggest take home message here is that stride rate can and does vary considerably with speed, and also between individuals. The 180 number gets thrown around a lot, but I see no reason why this number need be the gold standard that everyone should shoot for.
But as journalist, physicist, and former elite runner Alex Hutchinson notes, the 180-strides-per-minute benchmark isn't all it's cracked up to be. There are serious problems with Daniels's observations (among them, a small sample size and no analysis of stride length plotted against speed), and other research has contradicted some of its conclusions. More likely, Hutchinson writes, runners play with both stride length and stride frequency when they run, and 180 makes sense at some speeds and not at others. Blogger and Nike coach Steve Magness has made similar observations.
Why is this important? In reporting of the form story, the 180-strides-per-minute rule came up as one of the few objective measures of good form. Nobody said it was the most important measure—if good form exists, it probably has more to do with dorsiflexion angles and knee position at ground contact—but for runners to change form, it helps to know what to aim for. And it's much easier to count strides than it is to measure dorsiflexion angles, never mind figure out what dorsiflexion means.
It is shame that so many aspects of this concept of 180 steps/minute is underpinned by the misuse, misrepresentation and misunderstanding of the research evidence (or lack of), not to mention the cherry picking and confirmation biases ... let alone the making up things! Despite that, as I said above, it is gaining legs as a means to treat and prevent injury.
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
These days I try to avoid these kind of threads because they seem to pull in the non-healthcare professionals (i.e. amateur runners), but here goes....
Lets start with a bit of Socratic learning- why do people adopt a given natural cadence when running?
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
"Yet beginning and recreational runners typically have a cadence closer to 160, which Daniels* says puts them at risk for injury because the longer strides necessitated by a slower cadence take runners higher off the ground. This in turn means that each footfall is harder, and many running injuries are associated with the shock of landing. While Daniels can’t cite a study associating slow cadence with running injuries, I put a lot of weight on his experience coaching thousands of runners."
Nope, just plain old slower running with identical kinematics will result in a lower cadence regardless of "height off the ground". JEEZ, there is so much wrong with the above statement
Set the right hand slider to 1 N/m and press start allow it to run for about 10 seconds, press stop. Set the righthand slider to 100 N/m press start.
Things to note- the amplitude of the oscillation is unchanged; the frequency of the oscillation increases with increasing spring stiffness- think about the implications of this when running is modelled as a spring mass system.
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
I believe what is missing from the consideration of force reduction with increased cadence is 1) Velocity of forward progression and 2) In what respect force is reduced. So if the velocity of forward progression is constant then increasing cadence will attenuate the GRF impulse/integral at the foot ground interface at each step.
Dave
__________________
Descartes seems to consider here that beliefs formed by pure reasoning are less doubtful than those formed through perception.
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
Quote:
Originally Posted by David Smith
I believe what is missing from the consideration of force reduction with increased cadence is 1) Velocity of forward progression and 2) In what respect force is reduced. So if the velocity of forward progression is constant then increasing cadence will attenuate the GRF impulse/integral at the foot ground interface at each step.
Dave
increase or decrease rather than increase alone I would argue
as in a formula where n = 1 at which if 180 is the cadence there will some who increase and some who decrease there cadence.
so some will increase their impacts per min some will decrease - if this takes them into or out of their own personal physiological window will determine injury chance.
got to go finish some electric wiring before I finish the shed attached to the caport before the snow stays
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
Quote:
Originally Posted by mike weber
increase or decrease rather than increase alone I would argue
as in a formula where n = 1 at which if 180 is the cadence there will some who increase and some who decrease there cadence.
so some will increase their impacts per min some will decrease - if this takes them into or out of their own personal physiological window will determine injury chance.
got to go finish some electric wiring before I finish the shed attached to the caport before the snow stays
have a good weekend
Actually Mike my first statement was not entirely correct since this person (quoted in Craig's OP) did equate velocity with cadence.
"How can you limit this force? A more recent study suggests that one way this can be achieved is by reducing stride length while maintaining the same speed. The only way to reduce stride length at a constant speed is to increase cadence, which is exactly what Daniels suggests. The researchers analyzed the stride of runners who decreased stride length—and increased their cadence—by ten percent and found a significantly decreased chance of injury. This isn’t a true empirical test, but the model the researchers used did find that likelihood of injury is reduced with a shorter stride. The other studies Hreljac mentions in his review support this model: They find fewer real-world injuries in runners with less vertical impact in each stride."
The 'recent study' they refer to is this one:
Effects of stride length and running mileage on a probabilistic stress fracture model.
Edwards WB, Taylor D, Rudolphi TJ, Gillette JC, Derrick TR.
Source
Department of Kinesiology, Iowa State University, Ames, IA 50011-1160, USA. edwards9@iastate.edu
Abstract
The fatigue life of bone is inversely related to strain magnitude. Decreasing stride length is a potential mechanism of strain reduction during running. If stride length is decreased, the number of loading cycles will increase for a given mileage. It is unclear if increased loading cycles are detrimental to skeletal health despite reductions in strain.
PURPOSE:
To determine the effects of stride length and running mileage on the probability of tibial stress fracture.
METHODS:
Ten male subjects ran overground at their preferred running velocity during two conditions: preferred stride length and 10% reduction in preferred stride length. Force platform and kinematic data were collected concurrently. A combination of experimental and musculoskeletal modeling techniques was used to determine joint contact forces acting on the distal tibia. Peak instantaneous joint contact forces served as inputs to a finite element model to estimate tibial strains during stance. Stress fracture probability for stride length conditions and three running mileages (3, 5, and 7 miles x d(-1)) were determined using a probabilistic model of bone damage, repair, and adaptation. Differences in stress fracture probability were compared between conditions using a 2 x 3 repeated-measures ANOVA.
RESULTS:
The main effects of stride length (P = 0.017) and running mileage (P = 0.001) were significant. Reducing stride length decreased the probability of stress fracture by 3% to 6%. Increasing running mileage increased the probability of stress fracture by 4% to 10%.
CONCLUSIONS:
Results suggest that strain magnitude plays a more important role in stress fracture development than the total number of loading cycles. Runners wishing to decrease their probability for tibial stress fracture may benefit from a 10% reduction in stride length.
This correlates force with stress fracture (osseous) but of course if we consider injuries in general then soft tissues are more likely to be involved most times I would imagine and therefore soft tissue stress may not be directly related to peak vGRF of force integral/impulse at the foot- ground interface.
Although (IMO) in ambulatory exercises and for a given kinematic action of interest, the injury probability is likely to be directly linked to change in GRF in one or several orthogonal directions. However, a change in cadence will result in a change of kinematic action of interest so varying cadences could not be directly compared in this way.
Dave
__________________
Descartes seems to consider here that beliefs formed by pure reasoning are less doubtful than those formed through perception.
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
Quote:
Originally Posted by Simon Spooner
These days I try to avoid these kind of threads because they seem to pull in the non-healthcare professionals (i.e. amateur runners), but here goes....
Lets start with a bit of Socratic learning- why do people adopt a given natural cadence when running?
My understanding is that individuals will tend to naturally pick the cadence (along with other linked running characteristics) which is the most metabolically efficient for them
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
Quote:
Originally Posted by David Smith
Actually Mike my first statement was not entirely correct since this person (quoted in Craig's OP) did equate velocity with cadence.
"How can you limit this force? A more recent study suggests that one way this can be achieved is by reducing stride length while maintaining the same speed. The only way to reduce stride length at a constant speed is to increase cadence, which is exactly what Daniels suggests. The researchers analyzed the stride of runners who decreased stride length—and increased their cadence—by ten percent and found a significantly decreased chance of injury. This isn’t a true empirical test, but the model the researchers used did find that likelihood of injury is reduced with a shorter stride. The other studies Hreljac mentions in his review support this model: They find fewer real-world injuries in runners with less vertical impact in each stride."
The 'recent study' they refer to is this one:
Effects of stride length and running mileage on a probabilistic stress fracture model.
Edwards WB, Taylor D, Rudolphi TJ, Gillette JC, Derrick TR.
Source
Department of Kinesiology, Iowa State University, Ames, IA 50011-1160, USA. edwards9@iastate.edu
Abstract
The fatigue life of bone is inversely related to strain magnitude. Decreasing stride length is a potential mechanism of strain reduction during running. If stride length is decreased, the number of loading cycles will increase for a given mileage. It is unclear if increased loading cycles are detrimental to skeletal health despite reductions in strain.
PURPOSE:
To determine the effects of stride length and running mileage on the probability of tibial stress fracture.
METHODS:
Ten male subjects ran overground at their preferred running velocity during two conditions: preferred stride length and 10% reduction in preferred stride length. Force platform and kinematic data were collected concurrently. A combination of experimental and musculoskeletal modeling techniques was used to determine joint contact forces acting on the distal tibia. Peak instantaneous joint contact forces served as inputs to a finite element model to estimate tibial strains during stance. Stress fracture probability for stride length conditions and three running mileages (3, 5, and 7 miles x d(-1)) were determined using a probabilistic model of bone damage, repair, and adaptation. Differences in stress fracture probability were compared between conditions using a 2 x 3 repeated-measures ANOVA.
RESULTS:
The main effects of stride length (P = 0.017) and running mileage (P = 0.001) were significant. Reducing stride length decreased the probability of stress fracture by 3% to 6%. Increasing running mileage increased the probability of stress fracture by 4% to 10%.
CONCLUSIONS:
Results suggest that strain magnitude plays a more important role in stress fracture development than the total number of loading cycles. Runners wishing to decrease their probability for tibial stress fracture may benefit from a 10% reduction in stride length.
This correlates force with stress fracture (osseous) but of course if we consider injuries in general then soft tissues are more likely to be involved most times I would imagine and therefore soft tissue stress may not be directly related to peak vGRF of force integral/impulse at the foot- ground interface.
Although (IMO) in ambulatory exercises and for a given kinematic action of interest, the injury probability is likely to be directly linked to change in GRF in one or several orthogonal directions. However, a change in cadence will result in a change of kinematic action of interest so varying cadences could not be directly compared in this way.
Conclusions
For a given mileage, a decrease in running speed
reduces the likelihood for tibial stress fracture.
Strain magnitude may play a more important role in
stress fracture development than the total number of
loading cycles.
Thanks Ian, this appears to agree with both Simon and I and is consistent with normal engineering criteria that high peak loads at fast loading rates = material fracture and failure. Although some research lately appears to indicate that it is the rate of loading and not the peak load that determines injury/pathology in biological tissues. (Can't find the ref to cite at present.)
Dave
__________________
Descartes seems to consider here that beliefs formed by pure reasoning are less doubtful than those formed through perception.
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
One of the most important points to consider in this discussion is that the step frequency for increased metabolic efficiency may not necessarily also be the step frequency needed to minimize injury production. So, when someone says that 180 steps/minute is the ideal cadence, we must first ask "ideal for what?"
Secondly, one also needs to consider leg length in the equation for step frequency optimization. Individuals with longer legs will naturally run with decreased step frequency than individuals with shorter legs.
Finally, one must consider the running velocity when talking optimizing step frequency. Faster running speeds will show increased step frequencies and slower running speeds will show decreased step frequencies.
In other words, to say that every runner "runs best at a cadence of 180 steps per minute" is not only over-simplifying a complex neuromechanical-metabolic event for the bipedal human but may be absolutely wrong for many runners, leading them toward decreased metabolic efficiency and increased injury rates during running.
Here is a nice posting from RunBlogger on the subject.
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
Here is where I'm at: a spring mass oscillator (a human runner) has a natural frequency (cadence) which is determined largely by the stiffness of the spring (leg). When a runner runs they should aim to match their cadence to their leg stiffness + surface stiffness (lets call this the net system stiffness). When the frequency of oscillation (cadence) is mismatched to the net system stiffness then the metabolic cost increases and the likelihood of injury increases as the stress on the tissues is likely increased in this situation too. I'm also guessing the body naturally and automatically attempts to match the cadence to the net system stiffness, and this is how it naturally adopts the most metabolically efficient cadence; fannying about with cadence will probably lead to injury if not managed correctly- just guessing.
This is all very Tom McMahon, but then he is one of my heroes. Perhaps he should be included in the "classic papers thread", Kevin?
Thx, I missed that. I going to update the first post with some comments from there, so the post is more complete.
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
I to have noticed this 180 come up recently to. Following some of Paynie's links and reading about both sides does it not strike everyone about the total lack of evidence of either view. Yet despite this, look at the strength of the claims being made for it. Clinically we are being forced more to an evidence based practice. What about the running coaches doing the same?
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
My 2 cents on a topic close to my heart.
I ran at a reasonable level through my teenage years and into my 20's. I eventually stopped after battling bilateral medial tibial stress syndrome for 9 years. Everything short of surgery including shoes/orthotics, ice/anti-inflams, stretching/massage, running surface, workload, was addressed with modest success.
After 6 years away from running and now working as a podiatrist, I began training to compete in triathlons. Despite a gradual build up over several months, MTSS along with knee pain sufaced. My experienced physio examined my gait and said I "run like an elephant" (I weigh 67kg) and that I need to land more softly. Armed with this advice, through trial and error I found the best way to "land softly" was to reduce my stride length with a subsequent reduction in hip flexion, adopting a midfoot strike pattern and increasing my cadence. It probably took me around 6 months for the change in gait to start feeling normal and sustainable over distance. I did notice that initially it seemed to take more effort and like previous comments, I wondered about the body choosing a cadence that is most metabolically efficient.
After 2 years, three marathons and several half marathons later, I'm running relatively injury free. Changing gait has had the biggest impact on reducing my injury rate than any other measure I have attempted. Unfortunately, I don't seem to be any quicker... probably getting too old for this.
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
Changes in muscle activation patterns when running step rate is increased.
Chumanov ES, Wille CM, Michalski MP, Heiderscheit BC. Gait Posture. 2012 Mar 16.
Quote:
Running with a step rate 5-10% greater than one's preferred can substantially reduce lower extremity joint moments and powers, and has been suggested as a possible strategy to aid in running injury management. The purpose of this study was to examine how neuromuscular activity changes with an increase in step rate during running. Forty-five injury-free, recreational runners participated in this study. Three-dimensional motion, ground reaction forces, and electromyography (EMG) of 8 muscles (rectus femoris, vastus lateralis, medial gastrocnemius, tibialis anterior, medial and lateral hamstrings, and gluteus medius and maximus) were recorded as each subject ran at their preferred speed for three different step rate conditions: preferred, +5% and +10% of preferred. Outcome measures included mean normalized EMG activity for each muscle at specific periods during the gait cycle. Muscle activities were found to predominantly increase during late swing, with no significant change in activities during the loading response. This increased muscle activity in anticipation of foot-ground contact likely alters the landing posture of the limb and the subsequent negative work performed by the joints during stance phase. Further, the increased activity observed in the gluteus maximus and medius suggests running with a greater step rate may have therapeutic benefits to those with anterior knee pain.
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
Step Frequency and Lower Extremity Loading During Running
Hobara, H.; Sato, T.; Sakaguchi, M.; Sato, T.; Nakazawa, K. Int J Sports Med 2012; 33(04): 310-313
Quote:
The purpose of the present study was to ascertain whether increase in step frequency at a given velocity during running reduces the lower extremity loading variables, which is associated with tibial stress fracture in runner. We hypothesized that the lower extremity loading variables at a given speed would be minimized at around + 15% f step. 10 male subjects were asked to run at 2.5 m/s on a treadmill-mounted force platform. 5 step frequencies were controlled using a metronome: the preferred, below preferred ( − 15 and − 30%) and above preferred ( + 15 and + 30%). From the vertical ground reaction force, we measured following lower extremity loading variables; vertical impact peak (VIP), vertical instantaneous loading rate (VILR) and vertical average loading rate (VALR). We found that there were significant differences in lower extremity loading variables among 5 step frequency conditions. Furthermore, quadratic regression analyses revealed that the minimum loading variable frequencies were 17.25, 17.55, and 18.07% of preferred step frequency for VIP, VILR and VIAR, respectively. Thus, adopting a step frequency greater than one's preferred may be practical in reducing the risk of developing a tibial stress fracture by decreasing lower extremity loading variables.
(BTW, we posted the slow motion videos from the USA Olympic Trials here)
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
Quote:
Originally Posted by Simon Spooner
Here is where I'm at: a spring mass oscillator (a human runner) has a natural frequency (cadence) which is determined largely by the stiffness of the spring (leg). When a runner runs they should aim to match their cadence to their leg stiffness + surface stiffness (lets call this the net system stiffness). When the frequency of oscillation (cadence) is mismatched to the net system stiffness then the metabolic cost increases and the likelihood of injury increases as the stress on the tissues is likely increased in this situation too. I'm also guessing the body naturally and automatically attempts to match the cadence to the net system stiffness, and this is how it naturally adopts the most metabolically efficient cadence; fannying about with cadence will probably lead to injury if not managed correctly- just guessing.
This is all very Tom McMahon, but then he is one of my heroes. Perhaps he should be included in the "classic papers thread", Kevin?
Wot no Verne T. Inman in that thread?
It appears that stiffness is matched to cadence, not the other way around. Your spring-mass thought experiment is only valid if leg stiffness does not change with cadence (i.e. same spring, different frequencies) or if cadence is set in response to stiffness. But...
Human subjects ran on treadmill-mounted force platform at 2.5ms-1 while using a range of stride frequencies from 26% below to 36% above the preferred stride frequency. Force platform measurements revealed that the stiffness of the leg spring increased by 2.3-fold from 7.0 to 16.3 kNm-1 between the lowest and highest stride frequencies. The angle swept by the leg spring decreased at higher stride frequencies, partially offsetting the effect of the increased leg spring stiffness on the mechanical behavior of the spring-mass system. We conclude that the most important adjustment to the body's spring system to accommodate higher stride frequencies is that leg spring becomes stiffer.
The "180 is a magic number" is very old-hat, but don't throw out the baby with the bathwater. While you'll never see ANY runner cruising along at 4:30 mile pace with a stride frequency of 160 or 170, there are certainly some runners who have cadences that low at more moderate paces (7:00-8:00/mi). What interests me is not so much the individual response of cadence to changing paces (because of course cadence * stride length = speed, so to go faster one or both of those factors must increase), but the range of cadences amongst a GROUP of runners (of equal ability) at a given pace.
So, given a group of serious recreational marathoners who train at around 8:00/mi for 50mi/week, are the runners with a low cadence at higher risk for injury than the runners with a high risk of injury?
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
Quote:
Originally Posted by JohnD
It appears that stiffness is matched to cadence, not the other way around. Your spring-mass thought experiment is only valid if leg stiffness does not change with cadence (i.e. same spring, different frequencies) or if cadence is set in response to stiffness. But...
I never said leg stiffness doesn't change with cadence, what I did say was that for a given leg stiffness there is an optimal cadence, or if you like for a given cadence there is an optimal leg stiffness. I also said that if the cadence and leg stiffness was mismatched outside of this optimal zone then this may result in a decrease in metabolic efficiency and/ or an increase in injury risk.
How does a runner change their cadence if not by manipulating their leg stiffness, so does the leg stiffness drive the change in cadence or does the cadence drive the change in leg stiffness? Farley's work that you cited doesn't answer this. Moreover, it doesn't really matter. My contention is valid regardless.
Quote:
Originally Posted by Simon Spooner
Here is where I'm at: a spring mass oscillator (a human runner) has a natural frequency (cadence) which is determined largely by the stiffness of the spring (leg). When a runner runs they should aim to match their cadence to their leg stiffness + surface stiffness (lets call this the net system stiffness). When the frequency of oscillation (cadence) is mismatched to the net system stiffness then the metabolic cost increases and the likelihood of injury increases as the stress on the tissues is likely increased in this situation too. I'm also guessing the body naturally and automatically attempts to match the cadence to the net system stiffness, and this is how it naturally adopts the most metabolically efficient cadence; fannying about with cadence will probably lead to injury if not managed correctly- just guessing.
This is all very Tom McMahon, but then he is one of my heroes. Perhaps he should be included in the "classic papers thread", Kevin?
Wot no Verne T. Inman in that thread?
Lets say my natural self selected cadence was 180 steps per minute, but I consciously over-ride this and try to run at 240 steps/ minute; sure my leg stiffness will change, but so to has the muscular workload. My contention is that this will decrease metabolic efficiency and increase injury risk.
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
Quote:
Originally Posted by Simon Spooner
I never said leg stiffness doesn't change with cadence, what I did say was that for a given leg stiffness there is an optimal cadence, or if you like for a given cadence there is an optimal leg stiffness. I also said that if the cadence and leg stiffness was mismatched outside of this optimal zone then this may result in a decrease in metabolic efficiency and/ or an increase in injury risk.
I thought that I might try to save some time in this discussion... How can cadence and leg stiffness be mismatched? I hear you say. When runners change their cadence their leg stiffness changes. Or, was it that when they changed their leg stiffness their cadence changed? Never mind...
Because... variation in cadence does not explain 100% of the variance in leg stiffness, nor vice-versa. So, if other factors account for some of the variance in leg stiffness other than just cadence, then leg stiffness could be altered by these other factors irrespective of cadence? Yes. What about if it's the leg stiffness which "causes" the cadence? It might do, but other variables will also be predictors, so the same is true.
Lets try to make some sense out of the other point "JohnD" wrote:
Quote:
Originally Posted by JohnD
So, given a group of serious recreational marathoners who train at around 8:00/mi for 50mi/week, are the runners with a low cadence at higher risk for injury than the runners with a high risk of injury?
I presume he meant to write something like:
"are the runners with a low cadence at higher risk for injury than the runners with a higher cadence?"
Not necessarily. I'm not aware of any study which has demonstrated cadence per se to be a predictor of injury. Even if such a study existed, I'm sure there are other predictors of injury that should come into play. Given the link between leg stiffness and cadence, you could make the argument that the risk for specific types of injury may vary between the groups. http://www.udel.edu/PT/davis/stiffness_update.pdf but again, leg stiffness in isolation is not a universal predictor of pathology. It also gets complicated because we have evidence to suggest that fatigue may be a predictor of some injuries. We have evidence which suggests that someone running outside of their subconsciously selected cadence is less metabolically efficient; increasing fatigue which might increase the risk of injury too- lets say someone did this and got injured. Was it their cadence that "caused" the injury, or the fatigue level induced by this, or some other factor?
I guess it might depend on just how "serious" they are too along with how "recreational" they are
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
I'm unconvinced of this idea that the body naturally adapts to its ideal cadence and stride. While you are correct in that there is no (direct) evidence that high or low cadences are associated with injury, there is some peripheral evidence that indicates your natural adaptation may not be the most ideal, at least from an injury perspective:
Effects of stride length and running mileage on a probabilistic stress fracture model. Edwards WB, Taylor D, Rudolphi TJ, Gillette JC, Derrick TR. Med Sci Sports Exerc. 2009 Dec;41(12):2177-84.
Gait retraining to reduce lower extremity loading in runners. Crowell HP, Davis IS. Clin Biomech (Bristol, Avon). 2011 Jan;26(1):78-83.
Effects of step rate manipulation on joint mechanics during running. Heiderscheit BC, Chumanov ES, Michalski MP, Wille CM, Ryan MB. Med Sci Sports Exerc. 2011 Feb;43(2):296-302.
All of which indicate, in a small way, that active interventions (whether that be altering stride rate, running mechanics, etc.) may be able to reduce the risk of injury. Now, you may say that reduced joint loading associated with a +10% change in cadence is not directly linked to any injury, and you'd be right. But given the proposed "engineering perspective" that large load cycles and loading rates (not total number of loading cycles) is associated more strongly with injury (re the Edwards paper), AND given that increasing cadence appears to decrease the maximum load on joints, you would need to explain why lower joint loading increased injury risk rather than decreased it, as predicted.
The metabolic argument (higher O2 consumption --> more fatigue --> eventually more loading) is plausible, but given the rather small changes in O2 consumption at various stride lengths, I'm not yet convinced of that either. I would, however, like to see a study that examined changes in muscular fatigue (whether measured directly by strength testing or indirectly by EMG or similar) when comparing running at your natural cadence and an "adapted" cadence—as well as whether this difference in fatigue (if any) changes over time.
Some researchers have suggested that the body evolved to maximize metabolic efficiency at the expense of mechanical integrity—meaning, given the choice between lowering oxygen cost or lowering mechanical stress, the body will choose the former. Indeed, it does seem that the body is (at least initially) more efficient at its natural cadence, but 1) it is quite possible that the body can easily adapt and become efficient at a new cadence and 2) changes in VO2 over a range of cadences are rather mild:
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
Quote:
Originally Posted by JohnD
I'm unconvinced of this idea that the body naturally adapts to its ideal cadence and stride.
I'm a little pushed for time and interest. Being unconvinced is your prerogative. The fact remains that self selected running seems to be the most metabolically efficient as you state yourself later here. There are probably different ideals, one for metabolic efficiency and maybe a different one for speed. But fatigue is linked with injury.
Quote:
Originally Posted by JohnD
While you are correct in that there is no (direct) evidence that high or low cadences are associated with injury, there is some peripheral evidence that indicates your natural adaptation may not be the most ideal, at least from an injury perspective:
Yep, let me say this again: cadence is ony one factor which may or may not be a predictor for injury.
Quote:
Originally Posted by JohnD
Effects of stride length and running mileage on a probabilistic stress fracture model. Edwards WB, Taylor D, Rudolphi TJ, Gillette JC, Derrick TR. Med Sci Sports Exerc. 2009 Dec;41(12):2177-84.
Gait retraining to reduce lower extremity loading in runners. Crowell HP, Davis IS. Clin Biomech (Bristol, Avon). 2011 Jan;26(1):78-83.
Effects of step rate manipulation on joint mechanics during running. Heiderscheit BC, Chumanov ES, Michalski MP, Wille CM, Ryan MB. Med Sci Sports Exerc. 2011 Feb;43(2):296-302.
I don't have time to review these tonight, but I'm guessing that none of these demonstrated that cadence caused injury. Nor that cadence was altered without influencing any other factor. Just a guess.
Quote:
Originally Posted by JohnD
All of which indicate, in a small way, that active interventions (whether that be altering stride rate, running mechanics, etc.) may be able to reduce the risk of injury.
Do they really? As I said, I'll have to take your word for that tonight as I'm pretty busy. We can come back to this though- right? That someone gets better from an injury when cadence is altered does not mean that cadence caused the injury.
Quote:
Originally Posted by JohnD
Now, you may say that reduced joint loading associated with a +10% change in cadence is not directly linked to any injury, and you'd be right.
Thanks.
Quote:
Originally Posted by JohnD
But given the proposed "engineering perspective" that large load cycles and loading rates (not total number of loading cycles) is associated more strongly with injury (re the Edwards paper), AND given that increasing cadence appears to decrease the maximum load on joints, you would need to explain why lower joint loading increased injury risk rather than decreased it, as predicted.
I thought Nigg showed that increased loading didn't increase injury risk? If the load isn't on the joints, where has it gone? Increased cadence in association with decreased stride length = more loading cycles per metre- that might explain it, right?
Or, could active interventions increase the risk of injury? Any evidence here? Why might lower joint loading increase the risk of injury? More steps per metre; Viscoelasticity; ZOOS; increased soft tissue loading etc.
Quote:
Originally Posted by JohnD
The metabolic argument (higher O2 consumption --> more fatigue --> eventually more loading) is plausible,
I actually said increased fatigue has been shown to be linked to injury. Given the reports of this within the literature, it's obviously plausible.
Quote:
Originally Posted by JohnD
but given the rather small changes in O2 consumption at various stride lengths,
Clinical effect size?
Quote:
Originally Posted by JohnD
I'm not yet convinced of that either.
Like I said, that's your prerogative. And you are an expert in exercise physiology? Exercise medicine? Or, just a keen amateur runner?
Quote:
Originally Posted by JohnD
I would, however, like to see a study that examined changes in muscular fatigue (whether measured directly by strength testing or indirectly by EMG or similar) when comparing running at your natural cadence and an "adapted" cadence—as well as whether this difference in fatigue (if any) changes over time.
Some researchers have suggested that the body evolved to maximize metabolic efficiency at the expense of mechanical integrity—meaning, given the choice between lowering oxygen cost or lowering mechanical stress, the body will choose the former. Indeed, it does seem that the body is (at least initially) more efficient at its natural cadence, but 1) it is quite possible that the body can easily adapt and become efficient at a new cadence and 2) changes in VO2 over a range of cadences are rather mild:
There's also evidence that some people carry a gene which predisposes them to Achilles tendonosis..... The point is cadence is just one variable in a big old complex situation. Maybe if you introduced yourself properly, I'd be more inclined to spend more time answering you. Maybe if you referenced your contentions I might too. "You are not convinced" and you are? Meanwhile, I'm contributing my thoughts to a publication on foot orthoses tonight. It's my prerogative to not bother to respond here to keen amateur runners who are not foot health professionals, and to people who do not provide their real name. I'm sure you understand that too.
Re: Cadence of 180 steps/min to treat and reduce risk of running injury
Simon and John D,
The papers are attached.
I am in the middle of a lit review for tibial stress fractures so had them handy. The take home message from the review so far is that Stress fractures are multi-factorial in origin. (surprise!)
There seems to be a recent focus on vertical loading rate from researchers but is this variable more or less important than any of the other known risk factors for tibial stress fracture?? Such as free moment, peak rearfoot eversion, peak hip adduction, tibial cross section or section modulus, muscle fatigue increasing bone strain, female sex etc.
Of the attached studies:
The Crowell and HEIDERSCHEIT studies were conducted using a treadmill
The Edwards study was on 10 male subjects who ran overground in the lab. Discussion below:
DiscussionTherefore, runners
wanting to reduce their probability for tibial stress
fracture may benefit from a decrease in running
speed. This finding was a direct result of the
reduced joint contact forces and therefore reduced
strains associated with slower running speeds.
Because a reduction in running speed was also
associated with an increase in the number of loading
cycles for a given running mileage, it appears that
stress fracture development is more dependent on
loading magnitude rather than loading exposure.
This statement is of course specific to the
parameters investigated in this study and may
therefore not apply to different running velocities
and mileages.
Last edited by Craig Payne : 8th November 2012 at 11:31 AM.
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
Purpose/Hypothesis : Recent trends demonstrate an increase in the popularity of recreational running. With this increase, it is important to understand how running style influences plantar loading that has been linked to lower extremity injury. Our purpose was to evaluate the effects of cadence manipulation on plantar loading during running. It was hypothesized that increased cadence would result in decreased plantar loading in the rearfoot region.
Number of Subjects : 38 runners (19 males and 19 females; 22.98+3.52 years, 1.74+0.076 m, 30.59+4.70 kg)
Materials/Methods : Subjects ran on a treadmill at their preferred running speed while equipped with an in-shoe pressure sensor in the right shoe (Novel PedarX). Each subject ran 4 minutes in 3 cadence conditions: preferred, 5% increased, and 5% decreased. Kinetic data (contact time[CT], peak force[PF], force time integral[FTI], pressure time integral[PTI], and peak pressure[PP]) collected at 150Hz were recorded for 30 consecutive right footfalls. Data were averaged and analyzed for the total foot and 4 regions of the foot. Repeated-measures MANOVAs were used to evaluate the effect of cadence manipulation on plantar loading variables (α=0.05). Pairwise comparisons with Bonferroni adjustments were performed to evaluate condition differences.
Results : Overall, total foot plantar pressure variables differed between conditions (p<0.001). CT and PF were significantly lower with increased cadence as compared to preferred cadence. CT was significantly greater with decreased cadence as compared to preferred cadence. Plantar loading variables in 4 specific regions of the foot also differed with cadence manipulation (p<0.001). In the heel, FTI, PTI, and PP were significantly lower when cadence was increased. PF and PP were significantly greater when cadence was decreased. In the medial forefoot, CT, FTI, and PTI were significantly lower when cadence was increased. CT was significantly greater when cadence was decreased. In the central forefoot, CT, FTI, and PTI were significantly lower when cadence was increased and significantly greater when cadence was decreased. Finally, in the lateral forefoot, CT, PP, and PTI were significantly decreased when cadence was increased and PP was significantly increased when cadence was decreased.
Conclusions : These findings suggest that slight cadence manipulations alter total and regional plantar loading during running. A 5% increase in cadence resulted in runners experiencing, on average, 3.4% less time in contact with the ground during each foot strike. This resulted in 2.2% lower heel loading and 2.2-2.4% lower forefoot loading over time. Despite an increased number of steps, increasing cadence by 5% may have the potential to reduce loads in the heel by 565 BW*s and in the forefoot by 140-170 BW*s per mile.
Clinical Relevance : Increasing cadence by 5% in healthy runners decreases plantar loading associated with lower extremity injury. This suggests that cadence should be considered in technique training for runners and during the rehabilitation of running injuries associated with elevated plantar loading.
Purpose: The main aim of this study was to compare the freely chosen cadence (FCC) and the cadence at which the blood lactate concentration at constant power output is minimized (optimal cadence [Copt]). The second aim was to examine the effect of a concomitant change of road incline and body position on FCC, the maximal external power output (Pmax), and the corresponding Copt.
Methods: FCC, Copt, and Pmax were analyzed under 2 conditions: cycling on level ground in a dropped position (LGDP) and cycling uphill in an upright position (UHUP). Seven experienced cyclists participated in this study. They cycled on a treadmill to test the 2 main hypotheses: Experienced cyclists would choose an adequate cadence close to Copt independent of the cycling condition, and FCC and Copt would be lower and Pmax higher for UHUP than with LGDP.
Results: Most but not all experienced cyclists chose an adequate cadence close to Copt. Independent of the cycling condition, FCC and Copt were not statistically different. FCC (82.1 ± 11.1 and 89.3 ± 10.6 rpm, respectively) and Copt (81.5 ± 9.8 and 87.7 ± 10.9 rpm, respectively) were significantly lower and Pmax was significantly higher (2.0 ± 2.1%) for UHUP than for LGDP.
Conclusion: Most experienced cyclists choose a cadence near Copt to minimize peripheral fatigue at a given power output independent of the cycling condition. Furthermore, it is advantageous to use a lower cadence and a more upright body position during uphill cycling.
Cadence is one of the only variables cyclists can adjust to manage their performance and fatigue during an event. Not surprisingly, cadence has received a great deal of attention from the scientific community in an effort to identify the cadence that optimizes power output while minimizing the fatigue that is incurred. The literature appears to present conflicting results with little consensus as regards the optimal pedalling cadence. This is in large part due to the inconsistent definition of the term “optimal” cadence, which has been used to describe energetic cost, muscular stress, and perception of effort. The issue is further confounded by the workload-dependent nature of the “optimal” cadence – that is, at higher power outputs, the optimized cadence is different from that at lower power outputs. Although the optimal cadence is different for energetic, muscular, and perceptual definitions, the curves that describe the effect of changes in cadence on these variables consistently exhibit a J-shaped response. This suggests that there is an underlying principle that is common to each of the definitions. Indeed, it would appear that the response of both the cardio-respiratory system (energetic cost) and the muscular system (muscular stress) is determined by the types of muscle motor units that are recruited during the exercise. Furthermore, although part of the response may be due to the inherent differences in the characteristics between the different motor units, the absolute contraction velocity relative to fibre type optimum may be of greater significance. Even when the power output is increased, the shape of the response curves to changes in cadence remains constant, although the nadir of the curve does shift to the right for increasing power outputs. We propose that the point at which the energetic vs. power and the muscular stress vs. power curves intercept is defined by the cadence at which the perceived effort is minimized (i.e. the preferred cadence). However, cadence fluctuations occur under field conditions that are unrelated to physiological factors and, therefore, the ability to identify an “optimal” cadence is limited to the laboratory environment and specific field conditions.
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
Cadence of 180 steps/min to treat and reduce risk of running injury
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