Last May I was struggling with lateral knee pain. For days after the Taunton half marathon I couldn’t walk down stairs. I had tried a few things and was about to spend a lot on a trip to a podiatrist. Instead I went to TriUK in Yeovil and had a go at their “Mizuno Running Solution”. They picked out some shoes for me and I haven’t looked back – I haven’t had knee pain since (I have had Achilles discomfort, lateral foot pain and posterior tibial tendonitis mind you – but nothing terrible). I’m on my third pair of Mizuno’s now. My wife and kids have pairs too.
I have been using the Wave Mujin 3 shoes over the winter. They have taken me through umpteen muddy fields and down paths as well as covered a lot of road miles. I have probably done 400-500Km in them. They have been through the washing machine umpteen times (I know…).
I thought it was time for some new shoes. The Nike app texted me last week to say that their new lightweight Epic React Flyknits were available. 5 minutes later I had ordered a pair and they arrived last Wednesday. They have a new type of foam in (“React”). It’s durable and returns energy to the runner. It’s no Zoom Vaporfly 4%, with no carbon fibre plate (as far as I know). But it’s not exorbitantly expensive and the shoes expected to be durable – 600 miles or so.
On Friday I took them for a spin. On a treadmill. My “fast” mile felt easier than ever – rather than feeling as though I was going to pass out at the end of it, I was increasing the speed and went on for 2Km.
Psychological? Possibly. I firmly believe in psychology. I have a degree in it, and my PhD was on “central fatigue” – the concept that your brain limits your exercise capacity. I spent a lot of time doing transcranial magnetic stimulation. It’s odd to see the resurgence recently in brain stimulation. There is no doubt that new kit gives you a boost. But certain parameters, such as heart rate don’t (shouldn’t) lie.
Last night I settled down for some science. I’ll need to replicate this again, probably next Sunday, but the bottom line is that the new shoes seem faster.
Some methods. I warmed up outside with a 3K run up and down our local hill. I then did 5 intervals on our treadmill: 800m at 11.3Km/h then 800m at 16.2Km/h then a brief rest (I let the treadmill run at 9Km/h for 400m – 160s). A total of 8K. That rest time allowed me to slow down, get off the treadmill and change my shoes and my footpod (Polar). I used a Polar H10 heart rate strap and recorded it on my Garmin 935. The first interval was with the Mizuno shoes. Then two intervals with the Nike’s. Then an interval with the Mizuno’s and then a final interval with the Nike’s. For reference I weighed the shoes – a single Nike weighs 234g, a single Mizuno weighs 388g – an important difference.
Note I can run “faster” on the treadmill than in real life. I have just managed a Sub 20 5K on the treadmill, but it’s still just over (by about 40s) on the local 5K park run. 11.3Km/h is the speed I target for endurance. Last year that kept my heart rate about 130-135bpm. 16.2Km/h is the fastest I can sustain for a mile. Because I wanted to see if the new shoes were faster I didn’t want to hit my maximum heart rate and plateau, so although I can go a (little) bit faster over 800m I kept it at this level.
What did it show?
Firstly, it felt way easier with the Nike’s. There is a definite squish and you can feel the shoe deforming on impact with your toes and forefoot sinking into the shoe. You don’t get that with the Mizunos. But was it physiologically easier?
It looks like it was. See figure 1. It has two traces on it. There is an actual speed (according to the treadmill) line to demonstrate the intervals and a heart rate trace. The orange intervals are when I have the Mizuno’s on. The Black intervals are when I have the Nike’s on.
Figure 1.
Firstly, from left to right there is a gradual increase in heart rate. For me, running the 5 back to back intervals was hard. I’m also in a small, hot stuffy room. So I get tired and dehydrated.
But the interesting thing for me is that my peak heart rate is higher on interval 4 than interval 5, by just over 4 beats per minute. The trend would suggest it should be the other way around. Not much – but around 3%.
The really interesting thing is the speed data from the footpod though. The next chart (figure 2) shows the actual speed (calibrated – the actual data suggested I was much faster than I was!). As far as the footpod was concerned I was running more slowly (about 2Km/h) with the Nike’s on compared with the Mizuno’s, although the treadmill speed was the same.
Figure 2.
I’m not quite sure why this is. Running in the Nike’s changed my technique though. I felt a bit more tipped forward and a bit more on my toes. I also noticed a bounce, and I would imagine I spent more time in the air, allowing the treadmill to travel further beneath me.
I have summarised the data in the table (table 1). I can go faster on the treadmill in the Nike’s. But am I faster in real life? I’ll try to answer that soon. As soon as the weather dries up anyway and I have some time to do some intervals outside. I don’t want to get my Nike’s dirty yet, and time is a bit tight at the moment. I also need to do a long run first to see if they are comfortable enough. The toe box is a bit small, and I don’t know how my knee will stand up to things. If I can’t get on with them, back they will go. Despite the treadmill times.
Table 1.
| Interval | Shoe |
Treadmill Speed |
Footpod Speed | Mean Heart Rate |
Max Heart Rate |
| Interval 1 | Mizuno |
11.3 |
11.2 | 117 |
123 |
| Mizuno |
16.2 |
18.0 | 144 |
152 |
|
| Interval 2 | Nike |
11.3 |
11.0 | 118 |
125 |
| Nike |
16.2 |
15.0 | 143 |
150 |
|
| Interval 3 | Nike |
11.3 |
11.0 | 119 |
126 |
| Nike |
16.2 |
14.8 | 142 |
148 |
|
| Interval 4 | Mizuno |
11.3 |
10.9 | 124 |
130 |
| Mizuno |
16.2 |
17.3 | 149 |
155 |
|
| Interval 5 | Nike |
11.3 |
10.8 | 123 |
128 |
| Nike | 16.2 | 15.1 | 146 | 151 | |
| Interval 1+4 | Mizuno |
11.3 |
11.1 | 120 |
127 |
| Mizuno |
16.2 |
17.6 | 147 |
154 |
|
| Interval 2+3+5 | Nike |
11.3 |
10.9 | 120 |
126 |
| Nike |
16.2 |
15.0 | 144 |
150 |