Monthly Archives: March 2017

The Reebok Floatride Running Shoe

The Floatride from Reebok

Today I will tell you about my experience and recommendation regarding the Floatride, the latest distance running shoe by Reebok, to be launched in India this coming weekend, on 1st April 2017. The last time I spoke about a running shoe here was almost 2 years ago, about the ZPump Fusion, and was, quite coincidentally, also for Reebok. This time too, I agreed to do it on the same condition – that I would speak independently, with no interference from Reebok or their agents.

If last time for the ZPump Fusion my overall conclusion was neutral-bordering-on-negative, this time, for the Floatride it is significantly positive. If you want to read no further, and are looking for a pair of new running shoes, then go away with the thought “Puru the Guru says it’s a shoe worth having”.

Packaging, Size and First Impressions

Good things in small packages?

The shoe comes in a pretty standard box, unlike the lovely drawer pull-push style of the ZPump Fusion box that I still use for carrying things in my check-in luggage when travelling. That aside, the size I had picked for this pair was 2 sizes bigger than the shoe shop measurement of my foot. I find that “1-size bigger”, the rule-of-thumb recommendation for running shoes, is not good enough for me, and I like the fact that there is an odd amount of extra space north of the toes. This specification works for me; please note, I am not suggesting you do the same with your shoe sizing.


The shoe is sold in only one colour for men and another for women. The blue colour for men is not terribly exciting compared with the recent trend of “very bright and colourful” in the running shoe market. The lime green women’s shoe is also not eye-catching. The primary reason for this is that the ‘black surface area’ takes up a significant proportion of surface area in the Floatride. With running shoes, I love ‘bright and beautiful’, but if you prefer ‘not flashy’, then you will like these tones. And, whether or not you like ‘bright and beautiful’, if you care more about functionality and performance like I do, then too you will appreciate this shoe.

Special Feature

The official press release says that the “precisely-engineered Reebok Floatride Foam is pressure set for a consistent cell structure that provides an optimal mix of softness and responsiveness to ensure the wearer can experience high-level comfort while pushing performance”. I explored that claim.


One of the features of the lightweight ‘foam technology’ is evident in the total weight of the shoe itself. It is noticeably lighter at 285g than the trail running Salomon XScream (7% heavier) that has been my current favourite. It is also much lighter than the Asics Kayano 17 (20% heavier) that I have always felt I struggle with. It is heavier than the superlight Asics Gel-Hyperspeed racing shoe, but, other than its colour, I am not a big fan of that Asics racing shoe. I have not compared the Floatride with the running range from other leading brands but I am told by a friend that it compares well with the Adidas Ultra Boost in terms of ‘feel and fit’ – he has both shoes!

within acceptable tolerance; could be measurement error

I did notice that the left shoe was 3g (about 1%) lighter than the right shoe. That difference is about the weight of a walnut you might eat. I do not think it is material for me and I will not dwell on it – I am reporting it because I measured it! {Although I took repeated measurements to avoid measurement error, the difference might still be attributed to the precise weight measuring method I used, rather than the shoe itself.}

Boys in blue!

Testing the Shoes

Getting to know the shoes

I like to warm up to a new pair of running shoes by first wearing them for other light intensity activities. After that, I typically wear my running shoes only for running. So, prior to my first run I wore them:

  • At the gym for a session of strength training
  • For a couple of walks, including jumping across rocks at the seaside
  • When cycling, which is my most common mode of daily Mumbai city commuting

The Runs

This is a serious running shoe, so the main test for me was when I ran the following:

  • A gruelling afternoon run on Mumbai roads, with harsh sun and hills
  • An easy paced morning run on the beach, on both, firm wet sand as well as on soft and unstable sand
  • A set of 1600m intervals on slightly undulating roads one morning

The Run Experience

I loved that 10 minutes into my first run I had to remind myself that I was wearing a new pair of shoes. That itself made me decide that the Floatride was excellent for me. There was no ‘getting used to it gradually’ phenomenon to have to deal with.

Captured by a friend who happened to be passing by

Often with shoes (e.g. Asics Kayano that I have run in for more than 10 years) I find that the upper rim of the shoe digs in around my ankle and causes some discomfort and even pain, especially when new. I had none of that with the Floatride. So, am I pleased? Yes, very pleased!

Optimal mix of cushioning and responsiveness

With regards to Reebok’s claim about their ‘foam technology’, I agree that on the continuum of softness (think ‘luxury sedan smooth ride’) to responsiveness (think ‘sharp sports suspension’) the Floatride does an excellent job of compromising between the two. Full marks there too!

This pair was handed over to me a week ago for testing and voicing my opinion. I can see myself racing in the Reebok Floatride soon. I recommend it.



Dr Purnendu Nath spends his waking hours focusing on helping individuals and organizations reach their goals, to make the world a better place. He speaks, writes and advises on topics such as finance, investment management, discipline, education, self-improvement, exercise, nutrition, health and fitness, leadership and parenting.

Race Start Logistics – Chaos, Flow and Entropy

Should you really be up front in the crowd at the start line?

Have you ever run one of the big races in India like the Standard Chartered Mumbai Marathon (SCMM) or the Airtel Delhi Half Marathon (ADHM) and had varying experiences about the ‘flow of crowd of runners’? As the number of racers has grown and the increased focus on logistics for handling them has tried to avoid making a mess and avoid a human catastrophe, I have been curious about the flow of runners at the start and its subsequent impact along the route. Today’s conversation, with some interesting pictures, is about that. Takeaway lessons for you, racer, pacer or race organizer, will come soon.


I will first talk about the distribution of runners and how it transitions from start line to finish line. I then introduce you to my idea of ‘disorder’ in a race, with a measure that I call the Race Entropy, and show how that beautifully captures the flavour of the ease of flow within a race. I use the case of the Mumbai races (SCMM) to show how start-enclosures have helped with achieving less disorder (but significant room for improvement exists). I also show what impact the extreme pollution scares in New Delhi last winter had on the race that was held at that time (ADHM2016).

Gross Time, Net Time, Mat Crossing Time

I have shown you numerous graphs in the past of race finish times. These are typically histograms of ‘net finish times’ that show how many runners cross the finish line within each time bucket, where each bucket might be just a few seconds wide. What you will have probably never seen until today is a similar picture of what happens at the starting line.

How do we spread ourselves out over time?

Because not everyone crosses the starting line at the same time, there is a ‘spreading out’ or ‘distribution’ over time of runners crossing the starting line. This distribution is what leads to the need for recording gross finish time and net finish time.
The gross time is based on the natural clock time – the same clock for all the runners.
The net time is the specific time taken for each individual runner measured as, starting at their specific start line crossing (time = 0) and ending at their crossing the finish line.
Many races have RFID timing sensors placed under mats over which runners pass at the start/finish line, and so we often use the terms ‘starting line’ and ‘starting mat’ interchangeably.

Easing Flow

If your race’s logistics are handled smoothly, the fastest runners would be placed right up front at the start line and the slowest runners placed towards the back of the crowd. In the extreme scenario of the runners being released in descending order of their speed, in the hypothetical situation of constant speed for each runner, the number of ‘overtakings’ would be 0. No one would overtake anyone despite everyone running at their race pace. This would ensure a smooth flow of humans across the starting line and thereafter.

Smooth flow of runners ranked in order of speed

In practice, although it ‘feels good’ to overtake other runners, the truth is that it always involves some risk. Besides the physical risk (of impact) if the runner being overtaken sends you negative thoughts as you try to glide past him, that cannot be good for your soul.

Consider now, the worst situation for race start ordering, the slowest runner being placed right up front and the fastest runner at the back of the pack. In the extreme situation of N runners placed in such a reverse order of their speed, the fastest runner would have to overtake N-1 other runners to finish 1st. The runner who comes in second would have to overtake N-2 runners to come in 2nd. And so on for all the other runners… And, therefore, {ignoring the school maths proof}, the total number of ‘overtakings’ for all N runners would be ½*N*(N-1). Let us call that measure MaxPossibleOvertakings – e.g. for 10,000 participants placed in this reverse order MaxPossibleOvertakings will be 49,995,000.

Flow disrupted when runners not ranked in order of speed

For any given race with an actual ordering at the start line, we can also easily add up the minimum number of ‘overtakings’ that would have led to the actual finish ranking observed. Let us call this MinPossibleOvertakings.

Having defined a measure for the actual starting/finishing rankings of runners and the theoretical measure with maximum disorder, let me now tell you about what I call the ‘Race Entropy’ of an event. If numbers or equations faze you, hang in there, there’s nothing particularly complicated in what follows.


Borrowing from Thermodynamics, I define the measure of disorder in a race as being the ratio

Entropy – a measure of disorder in your race

If the runners are released in the perfect ranking of their eventual times, so that there will be no overtaking, the Race Entropy will be 0.
If the runners are released in the perfectly reverse order, the Race Entropy will be 1.
If the ordering is purely random chance, the Race Entropy will be approximately ½.
We hope that the Race Entropy for any race will be less than ½ and closer to 0.

Start-End Ranking Plot

We can also visualize this order and disorder with what I call a Start-End Ranking Plot – a rank for crossing the finish line plotted against the rank for crossing the start line. This example plot shows the two ends of [1] perfect order and [2] perfect disorder as well as [3] the case of purely random start ordering.

Start-End Ranking Plot: Avoiding disorder or wrong order is a worthy effort

Start-End Ranking Plot: Avoiding disorder or wrong order is a worthy effort

With this distilled single measure of disorder, Race Entropy, and the Start-End Ranking Plot, let us now examine a couple of interesting stories from the Indian recreational marathon scene.

Case 1 – Chaos to Order: Introduction of Enclosures for SCMM

The first year that I happened to run a distance race, quite by chance, was the flagship Mumbai Marathon in 2010 (SCMM2010). I remember being at the start line and witnessing the undignified pushing and jostling. It was pretty much ‘law of the jungle’ up there akin to the local trains I took to work daily. It was a free-for-all, first-come-first-serve type start, so everyone pushed up ahead, with no real attention to ordering themselves naturally by expected finish time.

Race Start Enclosures

Race start enclosures or ‘holding areas’ were first introduced to the Indian running scene in January 2012, at the Standard Chartered Mumbai Marathon. These enclosures, now common in the races with large numbers of participants, are set up with the philosophy that the fastest runners are kept together and typically go past the start line first, the slowest ones last, and the ones in-between following the same principle. In order to decide which start-enclosure you wait in before you start the race, race organizers request a recent race timing certificate from you at the time of registration. Based on this ‘previous timing certificate’ you, the customer, are allocated a start enclosure, specified visibly on your racing bib.

Pre/Post Enclosures

Start Enclosures help ensure reduced Race Entropy (disorder) despite an increase in competitors

If we examine the difference between 2010 & 2011 compared with 2016 & 2017 there is a noticeable reduction in Race Entropy despite the number of participants rising. Having seen the Race Entropy drop between 2010 to 2017 despite the massive increase in participation, we can see the Start-End Ranking Plot which corresponds to those numbers and the picture tells us the same story.

Comparing the Start-End Ranking Plot for 2010 with that from 2017 indicates a clear move away from high disorder towards greater order.

Population increase need not be a problem if mismanagement is replaced by better management!

Case 2 – Pollution Reduces Race Participation: Massive Reduction in Delhi Disorder

The flagship race of New Delhi, soon after the worldwide scares in the media about the city’s air pollution levels at the end of 2016, saw a massive reduction in actual participation on race day (ADHM2016). My simple but sensible estimation method tells me that 40% of those who had paid and were registered to race did not show up on race day. This is almost always fortunate for the race organizers and those who do show up to run. The race experience is always better for such large races when the turnout is lower {fewer people chasing the same resources including, quite literally, air, water and land}.

What did the fearless who turned up experience?

What is interesting is that the Race Entropy was so much lower (20.3%) than in 2012 (32.0%) when the ADHM first introduced start enclosures. It was also considerably lower than the previous year where in ADHM2015 the Race Entropy was 26.8%. Perhaps, the general time trend in Race Entropy shows that the running population itself is becoming slightly mature and sensible as a group about the race start. For ADHM2016, it is possible that a predominance of experienced runners showed up and many of the newer runners stayed away. Or, perhaps, managing fewer runners with arrangements for many more (who did not show up) induces lower Race Entropy (lower disorder). All my friends who ran ADHM2016 had a fantastic experience. As luck would have it the weather was (described by a mentee who ran) ‘absolutely perfect’ and my guess is that the reduced disorder added to a better overall experience.

Pollution Scares: Did the drop in crowding make humans more relaxed and reduce irrational crowding?

Once again, comparing the Start-End Ranking Plot for 2017 with that from 2012 when the number of participants was similar and start-enclosures had just been introduced indicates a clear move away from high disorder towards greater order.

Did the reduced crowd density encourage more orderly behaviour?

Summary and Way Forward

I introduced the concept of ‘disorder’ or Race Entropy to characterize the (lack of) ease of flow within a race. I showed how the introduction of start-enclosures based on ‘expected finish time’ helps reduce this Race Entropy (disorder). So, besides features such as aid stations, route marshaling, medal quality, pricing of race entry tickets, and post-race refreshments Race Entropy serves as a superb single measure to capture the overall race experience for those who turned up.

I will write again soon and provide guidance to you the racer, race pacer or race organizer based on this dimension of analysis.

Until then, try to not bump into anyone 🙂


Dr Purnendu Nath spends his waking hours focusing on helping individuals and organizations reach their goals, to make the world a better place. He speaks, writes and advises on topics such as finance, investment management, discipline, education, self-improvement, exercise, nutrition, health and fitness, leadership and parenting.