Nice video as always. And as almost always I will add little polemics: 1) To only try to have short contact time and nothing else can be counterproductive - it can end in ridiculously small superfast steps (something like some running drills) leading howerver into nonoptimal running speed. 2) To run on beach can be fun - the best way is to choos the place that touches the sea - there the sand is quite hard and bouncy (or at least stable), you can run there barefoot even if have never did so. 3) In rare cases longer contact time can be good - eg on wooden pavements that are elastic and bouncy with each step on them - so good way there is to accept the pavement "oscilation frequency" that will ease each step.
Also running shoes are an essential part of the equation. A softer more cushioned shoe will absorb more energy and thus will also increase contact time. Also, I feel like with some shoes if you have a contact time that is too short you don't actually allow the shoe midsole to compress and decompress, and thus you don't take full advantage of its elastic properties. So yeah, surfaces matter, but since we are all mostly running with running shoes, the shoe counts as another surface to take into consideration.
I'm guessing at the precise angles here, but virtually every elite distance runner lands with the foot-hip angle about 7 degrees in front of the hips and gets maximum thrust at toe-off with the foot-hip angle about 15 degrees behind the hips. The nominal time on the ground simply varies with pace and stride frequency. It's extremely rare to see and elite runner toe-off early, which would lower the ground contact time.
I just started running at 58. I love it. I did have some strokes in a car accident but it seems to be OK now. And your information is exciting. Are used to be a ballet dancer so I can comprehend mentally exactly what you’re saying. If I had a little more cash, I think I would invest in your program. But in the meanwhile, this will have to do. And I am enjoying it very much
Great video! Although shorter contact time is less tiring to do then longer contact time it is surely much harder to watch! I was getting dizzy just watching you bouncing around at the beginning of your video! Maybe running is about bouncing around and not jumping around! 🤣🤣🤣🤣 Great video!
Thank you, leaning forward is result of weak lower back muscles!! Need to do lower back exercise to strengthen, just by running it would take very long time to strengthen!!!!
Funnily enough I was running on a Motionmetrix machine this morning and a lot of our subsequent discussion was about ground contact time. Strength training seems to be a good way to improve, since stronger muscles can impart a higher impulse minimising required time on the ground.
This is the case. Strength training is great for reducing contact time. But also various exercises to improve stiffness and elasticity in tendons, etc. The Achilles tendon is very important for runners. The stronger and stiffer the Achilles tendon, the more elastic recoil you get. But I have also often met runners who in a test with MotioinMetrix have an energy return of maybe 7 per cent but after a few adjustments they go up to 38 per cent. They had the strength, stiffness and elasticity, but did not use it. Often because of things that I mention in the video like overstride and too much leaning, etc.
No. Like many other 'methods', there are parts that are not so bad. But a lot is not good at all. Like the fact that you can't run and actively pull your foot up towards your bum with every step and the leaning of your body is not at all what controls your pace, as Romanov claims.
So, if all this is true, then running shoes are an essential part of the equation, since a softer more squishy shoes will absorb more energy and thus act as the sand in your example, increasing the contact time of the foot. Should we all run barefoot and/or in minimalist shoes then? Or there's a trade of where sometimes it's ok to sacrifice a shorter contact time in favour of more cushioning?
i think running shoes are designed to provide sufficient rebound to minimise energy loss when touching the ground. They are soft but still provide elasticity.
While watching this video and before going out for the weekly 16 km run, I started for some unintentional reason to think that a running human could be a mass-spring pair. All the elastic structures form the spring which then carries all the body mass from feet up. This forms an oscillating system as any other mass-spring pair. Also, an oscillating system has a natural frequency. Think about a spring hanging from somewhere with something hanging in the spring. It oscillates up'n down. Now, the the optimum cadence would be the same as the natural oscillating frequency of the the runner, causing resonance. The resonance frequency is the only frequency to have any oscillating system receive energy. Could this be the basis for finding an optimum cadence? If yes, then I believe that each runner's cadence should be found out in a running lab of some sort instead of just throwing numbers into an equation. Or just go out and try different cadences and see if there's an obvious sweet spot that feels good.
Walk at 160 steps per minute (SPM) : 100% ground contact time. Jog low jump at 160 SPM : perhaps 80 - 90 % ground contact time shuffle, short stride length from inertia. Run high vertical jump at 160 SPM - 50% ground contact and 50% flight time for inertia to give long stride length. Focus on jump height and cadence to fly. Higher jump enables longer percentage flight by inertia time.
Love your videos! I'd love to see a video on where your power or forward motion comes from. Some say hips, some say lean forward, and some say from pushing off your feet. Which is the best and correct way?
Excellent question. That’s one of my biggest problems, forward propulsion as opposed to running in place.
8 місяців тому
You need almost no forward propulsion. It is that simple. You need enough forward propulsion to overcome air resistance, but that is almost negligible. Sprinters lean forward in the acceleration phase, however.
It is complete nonsense to claim the contact time shall be as short as possible. Image it is endless quick, then your feed has to take of again before even midstance. So the correct answer is that there is a sweetspot. Like a U-shape. Too short is bad and too long is bad. -> new video
With this in mind that a softer surface slows you down, do you think running in 'soft' shoes will actually slow you down or does the energy return from the shoe compensate for this?
8 місяців тому
Soft surfaces and soft shoes absorb energy. That energy is lost, ultimately slowing you down. However, hard surfaces combined with hard shoes can have a harder impact. It is possible to alleviate this with proper running technique.
Frederik, you may have some points that are valid, but it’s worth thinking about these things: 1. Elastic recoil is useful, but there’s a lot of inelasticity, which is why even the best runners have to put work into keeping their body in the air. Only a small proportion of effort goes to forward propulsion. 2. In this respect, contact time percentage is more relevant than contact time per stride. 3. If the percentage goes down, then the applied force will have to rise, proportionally. This can only be partly mitigated by increased elasticity, which I don’t know about. 4. The lean, which I think you are implying is from the ankles (lean from the waist is a choice), is inevitably determined by wind resistance at the current constant speed and any other choice leads to an immediate change in speed or falling over. Choice over lean is an illusion… ask a physicist. Andy Couldwell
Exactly. The 'forward lean' is not controllable without a corresponding change of pace. Indeed, the way in which we change pace is to subconsciously change the lean angle. Try starting to run without leaning forward, and then try to slow down without reducing the forward lean. Physics dictates that an increase in pace is necessary to stay upright as the centre of mass moves forwards. It's a similar case with 'over-striding', some on-line coaches advocate landing directly under your centre of mass, but physics dictates that it's simply not possible without falling flat on your face! Some degree of 'over-stride' is always necessary to stay upright. Even some elite distance runners appear to have a significant over-stride, and as the pace increases at middle-distance it increases further still. Likewise, GCT is predominantly a function of pace and can't be significantly influenced unless your form is desperately poor to start with (very low cadence and consequent excessive over-stride). If I compare my GCT (as a recreational runner in his mid 50's) with my county standard 17 year old son, we have identical GCT (as measured/estimated by Garmin watches & chest-straps) at a given pace. If he runs an 800m at something like 2:15/km pace his GCT is in the order of 170-175mS, but when he's jogging with me at a leisurely 5:00/km pace his GCT is the same as mine at around 240-245mS. The relationship between GCT and pace is more or less linear. Recreational runners may be lead to believe that their GCT time is too long, but that's only because they are running slower! Interestingly, the one area where my son and I differ at all paces is vertical oscillation, and more importantly oscillation ratio. Surprisingly my vertical ratio is actually lower than my son's, even though he's a very good runner at all distances from 800m up to half marathon. That would suggest that he could gain some running efficiency by trying to reduce his 'bounce'. Perhaps there's hope for me yet LOL.
Interesting and well explained! So...if walking on hard soil and rope jumping is beneficial to become more elastic, then training on stiffer shoes with less foam under your feat also is?
The "running in sand is harder because less elastic recoil" isn't a completely satisfactory explanation. Even with a completely inelastic posterior chain, power is wasted by moving sand away as you push - the sand acts as a damper which absorbs energy.
What exactly do you think _causes_ the low elastic recoil? Your comment is a bit like the saying "it wasn't the fall that hurt, it was the hitting the ground".
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Nice video as always. And as almost always I will add little polemics:
1) To only try to have short contact time and nothing else can be counterproductive - it can end in ridiculously small superfast steps (something like some running drills) leading howerver into nonoptimal running speed.
2) To run on beach can be fun - the best way is to choos the place that touches the sea - there the sand is quite hard and bouncy (or at least stable), you can run there barefoot even if have never did so.
3) In rare cases longer contact time can be good - eg on wooden pavements that are elastic and bouncy with each step on them - so good way there is to accept the pavement "oscilation frequency" that will ease each step.
Also running shoes are an essential part of the equation. A softer more cushioned shoe will absorb more energy and thus will also increase contact time. Also, I feel like with some shoes if you have a contact time that is too short you don't actually allow the shoe midsole to compress and decompress, and thus you don't take full advantage of its elastic properties. So yeah, surfaces matter, but since we are all mostly running with running shoes, the shoe counts as another surface to take into consideration.
I'm guessing at the precise angles here, but virtually every elite distance runner lands with the foot-hip angle about 7 degrees in front of the hips and gets maximum thrust at toe-off with the foot-hip angle about 15 degrees behind the hips. The nominal time on the ground simply varies with pace and stride frequency. It's extremely rare to see and elite runner toe-off early, which would lower the ground contact time.
Perfect information
I just started running at 58. I love it. I did have some strokes in a car accident but it seems to be OK now. And your information is exciting. Are used to be a ballet dancer so I can comprehend mentally exactly what you’re saying. If I had a little more cash, I think I would invest in your program. But in the meanwhile, this will have to do. And I am enjoying it very much
Fredrik, I love your videos. So cool. Peace & love👌🙋🙏
Great video!
Although shorter contact time is less tiring to do then longer contact time it is surely much harder to watch!
I was getting dizzy just watching you bouncing around at the beginning of your video!
Maybe running is about bouncing around and not jumping around! 🤣🤣🤣🤣
Great video!
Perfecto !!! Gracias por tu talento. Me estás haciendo ver la luz. Mi próximo trofeo te lo dedico. (67 años)
Thank you, leaning forward is result of weak lower back muscles!! Need to do lower back exercise to strengthen, just by running it would take very long time to strengthen!!!!
Funnily enough I was running on a Motionmetrix machine this morning and a lot of our subsequent discussion was about ground contact time. Strength training seems to be a good way to improve, since stronger muscles can impart a higher impulse minimising required time on the ground.
This is the case. Strength training is great for reducing contact time. But also various exercises to improve stiffness and elasticity in tendons, etc. The Achilles tendon is very important for runners. The stronger and stiffer the Achilles tendon, the more elastic recoil you get. But I have also often met runners who in a test with MotioinMetrix have an energy return of maybe 7 per cent but after a few adjustments they go up to 38 per cent. They had the strength, stiffness and elasticity, but did not use it. Often because of things that I mention in the video like overstride and too much leaning, etc.
I can imagine - it's an amazing tool in the right hands.
Would like to hear your thoughts on the pose method of running by Dr Romanov. Is it recommendable?
No. Like many other 'methods', there are parts that are not so bad. But a lot is not good at all. Like the fact that you can't run and actively pull your foot up towards your bum with every step and the leaning of your body is not at all what controls your pace, as Romanov claims.
So, if all this is true, then running shoes are an essential part of the equation, since a softer more squishy shoes will absorb more energy and thus act as the sand in your example, increasing the contact time of the foot. Should we all run barefoot and/or in minimalist shoes then? Or there's a trade of where sometimes it's ok to sacrifice a shorter contact time in favour of more cushioning?
i think running shoes are designed to provide sufficient rebound to minimise energy loss when touching the ground. They are soft but still provide elasticity.
@@Brurgh well, that depends a lot on the shoe
It's The Pjong Effect!
While watching this video and before going out for the weekly 16 km run, I started for some unintentional reason to think that a running human could be a mass-spring pair. All the elastic structures form the spring which then carries all the body mass from feet up. This forms an oscillating system as any other mass-spring pair. Also, an oscillating system has a natural frequency. Think about a spring hanging from somewhere with something hanging in the spring. It oscillates up'n down. Now, the the optimum cadence would be the same as the natural oscillating frequency of the the runner, causing resonance. The resonance frequency is the only frequency to have any oscillating system receive energy. Could this be the basis for finding an optimum cadence? If yes, then I believe that each runner's cadence should be found out in a running lab of some sort instead of just throwing numbers into an equation. Or just go out and try different cadences and see if there's an obvious sweet spot that feels good.
Walk at 160 steps per minute (SPM) : 100% ground contact time.
Jog low jump at 160 SPM : perhaps 80 - 90 % ground contact time shuffle, short stride length from inertia.
Run high vertical jump at 160 SPM - 50% ground contact and 50% flight time for inertia to give long stride length.
Focus on jump height and cadence to fly. Higher jump enables longer percentage flight by inertia time.
Love your videos!
I'd love to see a video on where your power or forward motion comes from. Some say hips, some say lean forward, and some say from pushing off your feet. Which is the best and correct way?
Excellent question. That’s one of my biggest problems, forward propulsion as opposed to running in place.
You need almost no forward propulsion. It is that simple.
You need enough forward propulsion to overcome air resistance, but that is almost negligible. Sprinters lean forward in the acceleration phase, however.
It is complete nonsense to claim the contact time shall be as short as possible. Image it is endless quick, then your feed has to take of again before even midstance. So the correct answer is that there is a sweetspot. Like a U-shape. Too short is bad and too long is bad. -> new video
With this in mind that a softer surface slows you down, do you think running in 'soft' shoes will actually slow you down or does the energy return from the shoe compensate for this?
Soft surfaces and soft shoes absorb energy. That energy is lost, ultimately slowing you down.
However, hard surfaces combined with hard shoes can have a harder impact. It is possible to alleviate this with proper running technique.
so if want to become stronger you should do the opposite?
I think Fredrik needs a sparkly cape when doing some of his intros. :)
2 and a half with this guy in my ears would be fun haha great video
SIR, THANK YOU VERY MUCH. LOVE FROM MY FAMILY.
The shorter the cadence, the shorter contact time.
+
Frederik, you may have some points that are valid, but it’s worth thinking about these things:
1. Elastic recoil is useful, but there’s a lot of inelasticity, which is why even the best runners have to put work into keeping their body in the air. Only a small proportion of effort goes to forward propulsion.
2. In this respect, contact time percentage is more relevant than contact time per stride.
3. If the percentage goes down, then the applied force will have to rise, proportionally. This can only be partly mitigated by increased elasticity, which I don’t know about.
4. The lean, which I think you are implying is from the ankles (lean from the waist is a choice), is inevitably determined by wind resistance at the current constant speed and any other choice leads to an immediate change in speed or falling over. Choice over lean is an illusion… ask a physicist.
Andy Couldwell
Exactly. The 'forward lean' is not controllable without a corresponding change of pace. Indeed, the way in which we change pace is to subconsciously change the lean angle. Try starting to run without leaning forward, and then try to slow down without reducing the forward lean. Physics dictates that an increase in pace is necessary to stay upright as the centre of mass moves forwards. It's a similar case with 'over-striding', some on-line coaches advocate landing directly under your centre of mass, but physics dictates that it's simply not possible without falling flat on your face! Some degree of 'over-stride' is always necessary to stay upright. Even some elite distance runners appear to have a significant over-stride, and as the pace increases at middle-distance it increases further still. Likewise, GCT is predominantly a function of pace and can't be significantly influenced unless your form is desperately poor to start with (very low cadence and consequent excessive over-stride). If I compare my GCT (as a recreational runner in his mid 50's) with my county standard 17 year old son, we have identical GCT (as measured/estimated by Garmin watches & chest-straps) at a given pace. If he runs an 800m at something like 2:15/km pace his GCT is in the order of 170-175mS, but when he's jogging with me at a leisurely 5:00/km pace his GCT is the same as mine at around 240-245mS. The relationship between GCT and pace is more or less linear. Recreational runners may be lead to believe that their GCT time is too long, but that's only because they are running slower! Interestingly, the one area where my son and I differ at all paces is vertical oscillation, and more importantly oscillation ratio. Surprisingly my vertical ratio is actually lower than my son's, even though he's a very good runner at all distances from 800m up to half marathon. That would suggest that he could gain some running efficiency by trying to reduce his 'bounce'. Perhaps there's hope for me yet LOL.
problem is then 1. how to know where your foot lands. 2. if it lands too far how to change ti
And that's why I've created an online course that teaches you exactly that 😃
Interesting and well explained! So...if walking on hard soil and rope jumping is beneficial to become more elastic, then training on stiffer shoes with less foam under your feat also is?
I run in barefoot shoes. Guess that gives you the edge if you use regular ones for races.
The "running in sand is harder because less elastic recoil" isn't a completely satisfactory explanation. Even with a completely inelastic posterior chain, power is wasted by moving sand away as you push - the sand acts as a damper which absorbs energy.
which means your feet are in contact with the ground longer and therefore not providing any elastic rebound. Its all part of the same mechanism.
What exactly do you think _causes_ the low elastic recoil?
Your comment is a bit like the saying "it wasn't the fall that hurt, it was the hitting the ground".