Negative Splits in a race... (Page 3)

Actually mile three was downhill and mile 10 uphill.  2 and 4 were fairly flat, just planned slower than the 2nd half.

Exactly ...... my point in bringing up the topic is that to optimze your performance one should never "plan' on going for a neg. split.  As we keep saying, knowing a pace that you can sustain and running that throughout is a better approach that will yield a better performance (once again in my opinion and experience).

As I believe I mentioned before, i'm not advocating going out and running a 1/2 PR followed by a minute per mile drop in the second half, but that solid but smart pacing in the beginning will allow you to maximize your potential as opposed to intentionally (or even unintentionally) "holding back" that first portion.

I guess that is where knowing your body well or using a HRM can be a benefit the runner tremendously.  If you know your training MP was at say 7:45 then come race day you can click those off and have a good sense of what to expect come mile 18 - 20 (assuming you had successful training sessions at that distance without dramatic pace drops).  Or that if you know your LT is about 170, then you will be able to semi-comfortably run 165-ish without blowing up.  Then as the miles increase you may have to work harder on the RPE/HR scale to maintain the pace, but you should be able to.  This is in contrast to the person planning on running 160/8:05 the first half and then trying to jump up to 170/7:45 in the second.  Just not a good practice because at that point there are too many things that can go wrong and then your whole race is blown.

Pretty much; see this link for Gebrselassie WR at Berlin last year. His 1st 20k was 59:10 while his next 20k was 58:56, a slight negative split but comparing the avg between 1st half (2:58 min/km) and 2nd half (2:57 min/km) indicates to me it was a very even paced race. On the link you'll see that his opening 10k pace and his closing 10k pace was within 1 second of each other.

Again IMO an even pace race is the better way to race (as long as the course allows you to do so). Even a slight negative can be good as long as the race overall is pretty even paced, IOW the variability between the 1st and 2nd half is minimal. Otherwise I don't see how racing the 1st half considerably below your race pace is a good approach as you’ll have to make up that time in the 2^nd half anyway.

I haven't entered this conversation before but have been reading it.

My coach has me try to negative split the runs in my tris for Olys. For my HIM that was the plan but wasn't going to happen with the weather situation and it was just about finishing. Sprints we do it but to a lesser degree since the run is short. I actually have done it my 1/2 Mary and that is the goal in 10K sort of distances running races.

We set a point in which I just run as fast/hard as I can. Depends on my fitness and where I am training wise that point varies but normally about with 3 miles left to go in an Oly. I'm not really a strong runner and place back of MOP for my AG.

I train to negative split my long runs when healthy where I'll run 50% at my aerobic pace then do the last 50% at a higher HR and RPE. It varies the distance I push depending how far out I am from my A race. It helps me to train the way I plan to race so I'm better able to do it come race day if possible.

Last race Oly I did, I was behind a thin women in my AG for a couple of miles, but when I pushed at the end, I passed her which is a rarely do but it was great for me as I finished probably 1-2 minutes before her and I only pushed last 2 miles as it was hot. I had planned to push it at about half way point, but knew my body didn't have it in me. For you gifted runners may not get it, but for me being able to pass folks is amazing and hasn't been all that common.

I learn pacing from trying it in races. One race I finished feeling really strong and knew I could have increased my pace sooner. It is all a learning process for me.

It works for me as my hard effort, lactic acid, wheezing all are at the end when I know soon I'll get to stop. For me a pretty slow runner it rocks to pass a bunch of folks the last mile on a race...it makes me feel good and it will be how I continue to try and run races as it works for me.

Why would it be any different?  You want to race your best, close to even splits is the way to go (let's assume a flat, windless course so we don't have topography or anything to get in the way).  The longer the race, the more negative splitting is likely to be better IMO because metering out perfectly even splits at your maximum is extremely difficult to execute.  And the penalty for screwing it up on the front end is large.

I'm listening.  But I think you're confusing things.  You have a way to pace yourself (HR) that you like and has been effective for you in leading to good results.  But you have to take different "variables" into account no matter how you choose to do this.  For example, you know that you have to account for HR drift as you pace yourself.  I know that the watts I target on the bike is a function of how long I'm going to spend on the bike and so may have to be adjusted if it's very windy.  If the course is net downhill for the first half, and uphill for the second then you wouldn't expect to achieve negative splits even in a well paced effort.

But all that is "noise" in my view.  Important noise to be sure for that day on that course.  The basic concept stands that the fastest way to the finish is to hold very close to a steady effort from start to finish.  You choose to measure that effort by monitoring HR.  Others choose pace or power.  Most all overlay PE onto those measures as well.

Perhaps we're getting too hung up on "negative splts".  The course & conditions will play a factor in whether you negative split by time.  But your race execution will ideally produce nearly even splts, quite possible slightly negative ones, if you've maximized your performance on an "imaginary fair course". 

And, no, it's not different for a triathlon.  Again, in my opinion. 

I don't know if that's more or less confusing now, but it's all I've got for tonight.  Enjoy the weekend--train well!

Mike,

Look at what happens when you start out too fast - just from a physiological standpoint:
your body creates lactic acid. you are going to hard to buffer it. you are forced to back off to recover. then you push the pace again when you feel better. this is how you get the bell shaped curve in your HR and pacing (upside down bell curve).  >>> as you know we produce lactic acid even when doing low intensity exercise such as walking, hence lactic acid is primarily a result of your body’s fuel choice for a given intensity. If what you meant by “going out too fast” was running above your MLSS point in which your body basically cannot go faster using fat for fuel relying more on CHO and resulting in higher lactic production then it could or couldn’t be a problem depending on the race distance.

When racing a 10k or 5k that would normal. Talking about a marathon, I could be racing at my lactate threshold pace (defined as lactic acid increase of 1 mmol/liter above athlete’s baseline) for the entire race hence that won’t be the limiter for me achieving the best possible race goal or not.  The limiter will be: what kind of pace/speed I have trained my body to endure the entire distance and spreading the effort over that (course dependant). I can certainly choose to go a tad slower and close a bit faster but as I said before if you are fit run a marathon at 7, 8, 9 min/mile then you can run the entire distance at that pace or with minor variances but if the difference  You might be able to do so if you are not fit enough or run harder with poor pacing.

So, wouldn't you rather run at a pace you can maintain, and then push hard at the end for a neg split, vs. starting out too hard and dying, recovering and then picking it up again.  >>> I think we have similar opinions when it comes to pacing and I don’t think I’ve ever suggested running harder at the start and fading away in the end. I said IMO racing even splits or a slight negative split (low variance between 1^st half and 2^nd half) will yield a better finishing time than substantially holding back the 1^st half and trying to make it up the 2^nd half that to me indicates just a safe approach or even poor pacing. (Think of it like VI used for power analysis, you might not want a 1 result but you want it to be as close to it as possible)

In the end, I think this is a good conversation, but a silly one. IF ALL the WRs are neg split - swimming and running - then why would you want to race any other way? I don't understand that. >> when the fastest marathon in history 1^st 10K split was only 13 seconds slower than the last 10K and the avg pace every 5km was never over 3 seconds to me it indicates a pretty even split race. IOW I don’t think Haile Gebrselassie was holding much at beginning, he pretty much went fast at since mile 1 and as the race developed he adjusted properly (slowing down in the middle and speeding up at the end). Again I am not suggesting a positive split approach, but an even split or slight negative split one…

What a great topic. Love this discussion. I don't have enough experience, but definitely tried both ways.  It seems the closer I get to even splits, the better my race (whether positive split or negative split).  And I guess that is what most people are agreeing on.  The bigger the variance between the two halves, probably means the result wasn't at maximum potential.

Also, I did a quick google search, and not ALL World records are negative splits.  Especially, in swimming (and especially with more difficult strokes like butterfly, backstroke).  HOwever, there have been Marathon records, etc. that were/are positive splits.  It does happen.  Most are negative, from my limited research, but they do happen both ways.  Heck, didn't macca go out doing his first 5K in 5:40s or something like that???

Great discussion....really.

Let's get an example of a marathon, 42.2km: if at the starting line, that day, at that time, your body is able to run it at the best you can in 3hrs, so 4'15"/km you will see that you need to pass at the half marathon little bit slower than 4'15"/km, let's say in 1h31'. If then, you will notice a great solid performance in the last 3-5km, with an increasing speed and passing many dead runners at the end. NOt only that: you will cross the line without impacting too much your muscles since you minimized the usage of proteins as reserve for energy. When people finished the sugars as energy , since fats are too slow for producing energy, your body will tend to transform proteins in sugars which will result in a great great damage for your muscles, needing a long recovery after the race. That is the big pain that you will face on the legs the following days. Tipically people tend to stop when this process appear.
>>> In general the main causes for fatigue during exercise are related to the energy systems, buildup of metabolic byproducts and/or neuromuscular factors and they are not mutually exclusive. Usually the result of poor pacing during exercise results by stressing the muscles at a higher intensity for which the athlete is properly trained and it will result in glycogen depletion although the period of time for this to happen will vary. Furthermore proteins for healthy athletes provide less than 5% of starting material for ATP production and will only increase as CHO and fat stores are low and it usually happens after prolonged intense exercise like ultramarthon or Ironman.

For a marathon the chances you race intense or long enough for your muscles to rely more on protein for ATP production are lower hence is not the major limiter when it comes down to pacing strategy unless you grossly overestimate your pace/speed potential. Since the amounts of CHO and fat used for ATP production can be influenced by: training, fitness level, training intensity, exercise duration, diet, fatigue onset, economy of movement and fueling before and while exercising, hence stating that your body will rely on a bigger % of protein for ATP production my be an overstatement. If an athlete start out too fast during a marathon, most likley the natural body response will be to slow down as fatigue sets in (before getting to the point you suggest).

An athlete properly trained and aware of his/her ability to complete the race distance at certain speed can expect racing at that intensity covering the distance as fast as possible while spreading the effort. Via testing throughout the training leading up to the race one can make better predictions and pacing strategies based on current fitness level. The fact that many people blow up their racing by poor pacing it is a results of improper training, poor pacing strategy and overestimation for current fitness.

BTW, I've done short intense training (20 min) sessions and still I have muscle soreness and fatigue days follwoing the session. How can that be if I couldn't possibly get glycogen depleted on that time and relied on protein for ATP production?

Another reason to go for negative split is the motivation: looking at your watch, feling the good sensation of increasing speed give you another push to go till the end. It is always good to finish with increasing speed.
Again for the marathon example, any minutes below the 1h30 on the half, will paid at least the same at the crossing line and the pay back is exponential. If you pass 20 secs less, I would say that you are still there with 20secs more but if you pass 1min less, you will see higher than 1h30 for sure. Imagine in a extreme case that you pass in 1h20: wht do you expect at the end? I would expect either a stop at the 32nd km or something like around 3h30'. >>> again I don’t think anyone is suggesting a positive split approach by racing faster of one’s capabilities during the first half only to pay for it the 2^nd half (at least I am not suggesting that). That is just POOR pacing or wishful thinking.

Try to get whatever final result list of a marathon and take the first 100 and do a statistics over negative split and see. Then do the same for the last 100 people on the list: what do you notice? >>> the reason why so many people blow up in races is because IMO the majority do not have th fitness necessary to go the distance and the experience to pace properly. The reason why the FOP show a bigger realtion betwen even or sligght negative split pacing is because they are in better tune with their bodies and know what sort of effort/pace they can sustain.

In general, your body has an energy budget at the starting line of a race (whatever sport apart golf...): if you start faster than your potential finish time pace, you are going to finish this energy too soon and, very important, at the beginning your body tend to burn much more sugar than what you burn after 20mins. That's why the strategy is much more importante for ENDURANCE than for short races.  >>> see my response above.

I would apply it down to 20-30 mins event because below that, is very difficult to calibrate the speed: in a track and field, 5k, 1.5k, 3k, etc. are all anaerobic events and negative split looses his meaning. 10k is something in between and tipically I start to apply the concept on this length. >>> huh?!?!? You consider 5K, 3K or even a 1.5K anaerobic events? If you do you need to review your sport physiology text book because they aren’t

For multi sports events, the topic is more complicated but more or less you should try to apply it on each leg and I would say especially on the bike where you risk to burn the second part of your bike leg together with the full run leg. >>> not really. Proper pacing follows the same principle for triathlons, if you race faster than what you trained for you’ll blow up eventually either on the bike or the run. You can choose the safe approach and go easy and build up your effort until you push the higher intensity during the run. (good for beginners and/or inexperienced athletes) or you can choose to spread your effort among all 3 events based on your current fitness level and strive for a even pacing or a slight negative split but racing 1^st half substantially slow vs the 2^nd half is the safe way to complete your event but a miss opportunity to race near your potential.

What’s so difficult to understand about following an even or slight positive splits strategy???

I'm not sure what you don't agree with. 

I think you exhibited pretty good pacing in your races, but certainly not "flat".  And while I'm in no way saying you didn't have an awesome race at Kona (you did), I'm not sure how you would know for sure that it was your "max potential".  Honestly, I would bet money that it wasn't.  That's intended as both a compliment and push to do even better next time you go.

I believe you left everything out on the course.  The question is if you had 'held back' some earlier would you have gone faster later and netted a faster time.

I think you're misunderstanding me on the rest.  I dismissed course conditions earlier just to simplify the discussion.  Absolutely conditions and topography have to be considered.  But just like you can 'adjust' what you expect your HR to show at different points in the race or under different conditions, you can do the same with pace and power.  I don't hold '275' watts all day.  That's not the fastest way around the course.  As an example, you work harder (but go slower) up hills while you work easier (but go faster) down them.  This is true for power on the bike or pace on the run.

I do think power and pace are better metrics to use to pace yourself, but HR is also a reasonable alternative (you're very comfortable and it seems to work reasonably well for you so I wouldn't push you too hard to change just for the sake of it).  I've used it as both a primary and secondary 'pacer' before.

I'm very much in the camp that near-even splits while completely spending your energy is likely to produce maximal results (yes, you have to adjust this if the course is set-up to be faster in some sections versus others).  I'm not sure we realyy differ much, you just think about things from an HR-perspective and let pace fall out of that.

I don't divide a course in 2.  I pick a pace that I believe I can hold for the duration of the event.  Depending on how aggressive I want to be, I will pick a pace that I am 'very', 'reasonably' or 'somewhat' confident in holding.  If I've planned well, it will get harder but not slower.  If not, first I'm struggling not to slow down too much.  If that fails, I'm walking it in too.    Not very different in concept really.

But I'd submit that if your pacing will always produce a positive split, then it will be very difficult to maximize your performance.  This is different than saying you'll have a poor result.