Asphalt Junkies Spring 2013 - Closed (Page 41)

Somebody asked me why running faster results in a greater risk of injury than running slower.

It's a good question so I wanted to discuss it here for everyone's benefit.  I've read the scientific literature about ground reaction force in running.  "Ground Reaction Force" is a general term from physics for the 'equal and opposite reaction' you've always heard about.

It's measured using a force plate that runners run on and by seeing the forces put on to the running surface in all 3 dimensions, you know exactly what forces are being applied to the human body because they are exactly opposite and equal.

I couldn't find a graph that was representative of what I wanted to talk about so I'm going to have to describe it with words.  You've all probably seen the graph of the forces displayed in the 2 important dimensions.  There is downward (Y-axis) and forward (X-axis).  The Z axis also gets forces (sideways as you run) but those are minimal and don't pertain to the injury question.

The experimentation has found that the forward force is about 1/10th the vertical force and the lateral force is 1/100th of the vertical force.  This applies across the board.  However, the 'force' is just the 'area under the curve' if you will and it's proportional to the runner's body weight and cadence.  This means that a faster cadence/shorter stride applies less force for a given runner per stride (but not per run totalled).  It also means that if you lose weight you will apply less force per stride and per distance which decreases your stresses and metabolic cost.  You will be faster and have less injuries.

Of course you can shorten your stride if you can.  But I fear that a stride that's shortened at a given pace doesn't make you more efficient and therefore slower overall.  But let's consider running slower.  If you run slower your stride length decreases too.  This doesn't necessarily affect your stride rate, just shortens it. 

If you were looking at a graph of the ground reaction force of a runner's landing you'd see what would look like a bell curve with a short, sharp peak at the beginning before the normal bell curve shape finishes up the graph.  That peak is the heel strike.  But I would point out to you that experiments show this peak to have a force LESS than your body weight.  The 'stance' phase of the stride when you are over your leg is the highest point in the force curve.  Surely that's not the part of the running stride that injures you is it?  No, but neither is the landing per se. 

As you run faster the stride length increases.  Also, the dwell time on the ground decreases.  The longer stride length means that your ground force reaction is a higher 'force' in total (chance for more injury right there) and the length of the curve from touchdown to toe-off is shortened in duration.  But this requires a much higher peak force so that bell curve is now really tall and skinny instead of lower and wider.

So the force is applied much faster and results in a shock wave with a higher frequency.

There is also the need for the muscles to contract much faster so tendons are more violently contracted.  So running fast won't just increase the risk of impact injuries, but contraction injuries to muscles and tendons too. 

It's not that we shouldn't ever run fast, it's just an explanation as to why running faster increases our likelihood of injury.

Note on running fast.  The Pose guys like to say that to run faster you need to get your foot off the ground quicker.  I think that's backward.  I think the foot comes off the ground quicker because you run faster.  If you run faster you run faster.  Just getting your foot off the ground faster forces you to chop up your stride.

I'd be at least as right, maybe more, to tell you to lengthen your stride to get faster!  Keep your foot on the ground LONGER and you will lengthen your stride without reaching forward more.  And you tend to keep a fixed cadence so you will go faster that way more effectively, I think, than picking your feet up faster.  (this means distance running speeds, not sprinter speeds)

Yup, 1:1. Works perfectly and it is affordable. Especially if it keeps me away from the doctor for swimmer's ear.

Karl - You should throw in a little Tae Bo, maybe a round of Bikram Yoga, and some intense TRX training. Just kidding. I hear ya - tri training is more confusing than any other training I have done before, but I do love it! Leading up to the Tally Half, I will definitely be getting in some extra swims as my run tapers off over the week and half.

Jo- I am sorry to hear about your sisters and your oldest son. I am glad that you have shared with us what is going on and that you have a healthy outlet to release your frustrations. As a US Army veteran, I want to say thank you to your son for serving this country and I will be praying for his safety and for the recovery of both of your sisters.

A very good commentary.  It is more reinforcement that we could all use a slower running program to keep us on track to a more healthy active lifestyle.  I am finding out that running slower than I had been has been allowing a recovery from my plantar fasciitis without a complete stoppage of running.  (However!!  I wouldn't be going down this particular road of running with this injury if it weren't for the Boston Marathon.) 

Things will begin to look better soon.  You won't be given more than you can handle but that doesn't make it easy right now.  I will put you on my prayer list and you keep us all updated.  Make sure your son knows that I appreciate his service and will be praying for he ans his unit as well.

Karl congrats on the great swim session. Be persistent and keep at it and you'll get better. Also no ring on when I am doing any workouts. I always leave it off especially for swimming for fear of losing it.

JoAnne I'm sorry to hear about your older sister and your now being sent to Afghanistan. Your sister's and your son will be in my thoughts and prayers.

Nice work though on those workouts with the trainer and your bike ride. Sounds like your training is going well.

This is great advice Warren. We all tend to neglect rest and recovery. Rest and recovery is training and we all need it. Took me a long time to learn this lesson but I am slowly coming around to realize that it's important.

I think I am finally getting back into a routine although it has been hectic lately. Between work, taking care of the puppy and trying to get my training in I have been totally wiped out.  I can barely keep up with all the activity here. I was able to get to the pool and swim some today and I have completed the first two workouts of week 8 of Jorge's WCP. I was able to get a short 5 mile run in on Monday. That was cool it started snowing towards the end of the run.

Last night was rough though, those 6x4's @20 MP are just brutal. I could not hang at 20 MP as much as I tried. I just went as hard as I could for those 6 intervals. I think by the fourth one I was ready to quit. It took everything I had not to get off the bike and quit. I actually didn't do too bad on interval 5 and on 6 I was actually able to stay close and then over my 20 MP to finish strong. However I could barely do the CD at the end. I mean I totally got my butt handed to me on that workout. Tonight's workout was alot less taxing thankfully.

Actually no, I have only gone skiing at altitude, so this will be quite the experience.  It's one of the things that I asked the guides about and they said that wasn't as much of a concern as our physical shape.  So I think I'll be all right.

Another late Wednesday weigh-in.  I'm down to 18 lbs.  8 to go.  This week I'm really going to do my best to stay away from the junk food.  I've cut myself back to diet coke only a couple times a week now.  So far no headaches from the lack of caffeine, but it's really tough when you have a sick puppy on your hands and she keeps you up all night long whining....and then sleeps all day of course.

Heh heh heh!!!!!  Jorge and the puppy gotcha!  Great job!  Fun stuff there!  Can't wait until I can do some hard workouts.

I am struggling to remember to weigh in on Wednesday mornings but I actually did it yesterday.  I am at 17, which leave me with 7 to go.  My trouble has been that I am allowing more unnecessary calories by eating things when I don't actually need them.  This is an area I seem to always struggle with.

Wow you all are doing great with the weigh ins!

I just got a book from the library called The Feed Zone Cookbook Fast and Flavorful Food for Athletes. The authors are a chef and a Sports Scientist who worked with athletes on the professional cycling tour. I was paging through the cookbook last night and I'm surprised how much they use white rice, potatoes and bacon. There is even a whole section of recipes for foods that are portable on the bike.  Interesting book so far!

Quick question - I've been doing some strength training for my legs after I swim at the Y lately. I've finally increased the weights enough to actually feel it the next day. Yesterday I had a bike and run but my legs were tired from the strength training and I couldn't ride as hard as I have been. Today is another Y day (swim/weights), tomorrow ride and run, Saturday ride long. I'm kind of thinking I need to bail on the weights today to make it through the rest of my workouts this week but I also know I trend towards taking the easy way . My legs are not sore, just very fatigued.

So what should I do Junkies?

Congrats to everyone on the weight loss challenge everybody is doing a great job with it.

Dina if I feel sore after lifting and want to do S/B/R and think it will be affected or I am too tired I just skip the weights and do it another day. If you think you can do it I think that is ok too but if you don't feel up to it I think you can skip it.

Dina what are you doing for your leg exercises?

Actually I quit working my legs because I just couldn't run or bike afterwards.  I mean it would be 3 days after lifting just to walk normal.

Now saying that, I still think it is good to do some light hamstring work such as straight leg dead lifts or even leg curls.  I have also just started doing a couple of walking lunges just for the stretcf.  But as far as working the quads, you get enough of that biking, kicking on the kickboard and running.  Just my thoughts and I'm sure the mentors will correct me.

Does this "cookbook" include how to cook PED's?  With the recent discussion about Lance Armstrong I couln'd resist that little jab.

Stir in EPO and let sit for 5 minutes

Sorry you're not feeling well.  I'm still fighting a mild cold myself.  I *almost* want to stay home in my nice warm, cozy house for the day.  I really need to get an easy swim session done, though.  I'm bribing myself with a sauna session after swimming.  Good for the sinuses!

Jeff, hope you get to feeling better.  have you been to the dr?  Also have you tried a netipot, you can get them at all pharmacies, walmart etc.  People down here use it all the time for our sinuses, cleans and flushes.

Good luck