Stryd Power Analysis - Winery Half Marathon

If you are at all interested in training data and the developments in usable running metrics you've probably seen some of my videos or blogs on the Stryd's running power meter.

I use Stryd with nearly all of my runs, but choose carefully in my training when to do post-run power analysis, when to use it during a session and when not to worry about it at all. This past weekend was a great opportunity for me to see if I could gain any insights into my run.

On Saturday I set out on the 185km journey to the Hunter Valley on two wheels, the longest I've ridden since Kona 2015. It was a bit of a personal challenge for me and then to follow the ride up with the Winery Half Marathon the next day. I knew I'd be running the half marathon a bit underdone and a little sore and tired from the ride the day before so I thought it would be an ideal opportunity for some post race analysis on my power file to see if I could pick up any information that might help my run moving forward.

Winery Half Marathon

The course started with an 8km section on a golf course before heading onto the road for an out and back 10km and finishing off with 3km on the golf course again. The golf course section was quite windy with some short, sharp up and downs, the road section was fairly flat with 2 steady lumps in the middle (a couple of hundred meters long). The final 1km of the course was a steady up hill. I sat in for the first 4km before taking up the running to string out the group of 5 in the lead. I felt fairly strong aerobically most of the way, I just struggled over the final 3km with some tightness in my hamstrings and glutes (from the ride) - I'm still nursing this now!

As you can see below I ran around 75 minutes (I had 75:01, the race stuffed my time a bit and didnt call me across the line until a minute or so after I finished). I averaged 336w, 77w Form power and 173spm (cadence). So what does that mean????

 Race Overview

Race Overview

Conclusion 1

When I usually run around threshold pace (around 3.20-30/km) I am usually clipping off 175spm, I averaged slightly below this on race day but the small undulations and fatigue could've accounted for the decrease. You can see from the blue line below my cadence looks fairly consistent, a few up and downs at the start on the golf course and a slight decrease towards the end as I got back on the golf course and was nursing my legs up the hills.

Conclusion 2

In the picture below you can see a comparison of my cadence (blue), form power/technique (orange) and vertical oscillation (green). The conclusions I drew from here (highlighted with numbers below), during the section at around 55 minutes,  I was heading up the first of the 2 lumps on the road section. You can see my cadence drops slightly as I tried to shorten my stride and be more efficient, my form power went up (BAD!) and I created some additional vertical movement thus expending more energy (you can expect a bit of vertical increase as you head uphill due to resistance, but too much is not good) .

A goal here in future races or longer training runs could be maybe to see with positive form adjustment and cues whether I could focus on better forward momentum to limit these increases of power and loss of energy on the hills.

It's worth noting that in the race I tried to reduce my output on these hills and get back into my rhythm quickly off the top of the hill. It obviously didn't work out too bad.

Conclusion 3

The final picture below shows my laps for the race. My interest in this was to compare if at certain running speeds across each kilometer, was my power, form power or RSS (stress score) effected positively or negatively?

It looks like I spent most of my time running in power Zone 3 with an overall run stress score of 4. What you can see is that after kilometer 7 my RSS scores are always 5+ (higher), again expending more energy. This is also evident where my form power rises rises from 75/76 at the start of the race to consistently being 77/78 over the second half, As my pace was pretty consistent this could be an area to focus on improving as I fatigue (holding better form and power for a given pace).

** How does this work in a training situation**

Do some replicated repeats or consistent running on the same terrain and focus on trying to achieve a given power value for a given pace, especially as you fatigue.

Future Racing?

The next goal for me in terms of using my Stryd Power Meter might be to tackle a similar distance race with the goal of trying to use my power metrics to keep me on track now that I have a baseline. At the Winery Run I didn't look at my watch once and just ran by feelto see how I was going.

It would be a smooth transition to think that for a future half marathon I could try one of a few things:

1. Try to lower form power for the same pace giving me an overall increase in efficiency of energy output.

2. Try to increase my pace for the same power/ form power - focus on form adjustments in the second half of the race especially.

3. See if focus on increase in cadence or reduction in vertical oscillation can improve my power metrics and/or pace.

A little bit of trial and error and I'm sure with additional training this will begin to improve. As always I'll try and draw conclusions where I can and make adaptations without letting the data completely control what I do.

Happy Running!