Athletes comes in all different level of fitness and capabilities. Even ourselves, our heart rate differs everyday depending on our rest, performance and even the weather. So, to be training at "10 beat per minute" more than yesterday may very well meant different level of effort if you had a tough day or an easy day (at work or at training). However, having a consistent benchmark such as power, which is a function of force multiply by distance over time. It sort of provide a number where you can use to benchmark your training against. The level to generate 100Watt (W) when you are fresh or tired is the "same" to the power meter. But to get your heart to work to generate that 100W when you are tired, may meant busting your heart rate at Lactate Threshold than when you are fresh.
An analogy I could use would be to compare Heart Rate to a vehicle RPM while Power is the capacity. A car going uphill may require higher RPM (HR) to generate the same climbing power and definitely lesser RPM (HR) when you are moving on a flat ground. Now imagine if you can train at a given Power irrespective of your HR... you will become a more efficient cyclist or triathlete!
Garmin Vector 2S
Lucky for me, the good people in AECO Technologies, which is the authorized distributor of all Garmin products in Malaysia has been kind to provide myself and Chan a unit of their latest power meter to be used for our training. Chan has provided a write up on why in the team's blog. We both have been using the Vector2S and has compared a few notes on training. Among others, we soon found out that I can churn out more power compared to him. Question was - am I a stronger cyclist because I can fire up higher power? Now keep this question in mind while I continue today's review of the 2S.
First up is the Garmin Vector 2S itself. It is a pedal-mounted power meter. Other variations available in the market (for power meter of other brands) are crank mounted, bottom bracket mounted, hub mounted and crank-spider mounted. My exposure and knowledge was nil until the Garmin Vector 2S. This review will be specific for Garmin Vector 2S; until I manage to (afford???) another different type to compare.
The Garmin Vector 2S (I will call it 2S from now onward) is an upgrade from the original Vector where the older pod appears to be a ring (O) that goes through the bike spindle versus the newer Vector that has the pod coming as a clamp (()). The plus side? Easier installation. Meaning, You can remove the pedal and re-install it on another bike faster and easier. Ideally, I would think for such investment, you may unlikely remove the pedal and the pod. That is unless you decided to do so (or use a different bike setup like a road bike vs a TT bike) for race reasons.
|The closer look of the Pod clamp|
Vector 2S is single sided pod aka on the left pedal while the full fledged Vector 2 is both pedal - which gives you better left-right accuracy where power generation is concerned. On the "left" only power meter such as 2S, the total power are multiplied to provide the reading. While some of you may now argue the accuracy of a one-sided unit - I believe manufacturer like Garmin would had factored in this when building the algorithm to compensate or to correct the readings. For that, Garmin units has function of "Smoothness" in percentage (%) which could mean how smooth your pedaling motions are, and these translate to efficiency.
What's in the box?
|What comes in the box (top line) : Left Vector 2S pedal and sensing pod, right non-sensing pod, cleat, hardware to mount cleat, USB ANT+ stick and manuals|
|All laid out|
|Cleats in Red. In pouches, from top left clockwise : spacer ring for pod installation, hex screws and hex key, hardware to install the cleat and USB ANT+.|
The Look Keo compatible cleat can't be used on Shimano pedals - meaning, you would or may need to have an extra cleat shoe if your other bike or bikes runs on Shimano SPDs. For me, my Giro Tri Mele is used/converted for Garmin Vector 2S. The cleat supplied is the 6 degree float - which is really comfortable.
Below is how the Pod and the left pedal looked like when installed on the crank arm. I try to show it from different angle so you have a good idea how it will eventually look when installed.
You may had noticed the Pod has an additional "arm" that locks into the spindle. This is the how the unit collect and transmit the data from spindle to pod and finally to your Garmin device.
|The Extra arm with the contact points|
|The left pedal spindle where the arms with connector will contact|
Comparatively, the right pedal looked like any pedal spindle.
|Right pedal spindle|
|Very nice GARMIN and VECTOR imprinted on both the pedals|
|Proudly made by Exustar. You can adjust the tension here.|
My fear of installation revolves around the pod position and at which position the crank arm will be. The installation of the pedal is simple and direct. Be mindful not to over-tighten or under-tighten the pedals, as it may impact the accuracy of the power reading. Garmin recommend 34-40Nm. If you are not sure, the best guesstimate is just to screw in with hand until the surface of the nut and crank arm meet and give it a snug turn to sits it in. I have a torque wrench...but it maxed out at 20Nm... haha.
|Pod facing down with crank arm at leading edge or 9 o'clock position|
For this, the simplest approach available from Garmin is to place the pod downwards as the crank arm is at the forward position - looking at the left crank, it's at 9 o'clock position with the pod pointing down. To make it a bit easier to visualise, i am showing how it will look when the crank arm is at 3 o'clock position - the pod will face upwards. I try to make it as perpendicular (90 degrees) to the crank arm as possible.
My extra challenge is that I have the existing cadence and speed sensor, which I have to adjust and install onto the system. Good to note that the 2S collect Cadence data as well, but not speed. And I need the Speed data (because who don't?). :D The 2S takes precedence with the Cadence reading while the existing Cadence/Speed sensor provides me (stationary) speed on the trainer as the wheels turn. Win-win. Power-Cadence-Speed sorted!
The Manual is easy to understand. Once the whole system is installed, tighten and checked, I paired the unit to the Fenix3 (and also the 920xt), input the correct crank arm length and spin it between 70-90rpm to set the installation angle. This only need to be done once. Once it is set correctly, you will received a signal on your Garmin device that it is successful - and you are good to go!
|2S In Action|
Total time from start to getting the unit working took me about 15minutes including reading the manual from page to page. Thanks to Jun Shen as well, that provided a few pointers and assuring what I did was correct. Thank you sir!
|Jun Shen's Garmin Vector 2S installation instruction!|
Using the Power Data
It has been about 5 weeks since I've embarked on the Power journey. There are a few important numbers that the Power meter provide that sort of tells me the quality of my workout. When I first started using it, I pedaled the way I did and returned a rather bad reading, power wise. How can someone that claim to be training consistently brings home only 180w average power?
Power To Weight Ratio - Watt per Kilogram weight or W/kg
It was a wake up call when I only manage a 180w average. I realised I wasn't training the way I should be. To put things into perspective, (remember the question above?) Power itself is nothing if you got no other constant to measure against.
This critical data many failed to include is the cyclist/triathlete body weight. Two person may churn out (example) 100w and if both of them are 50kg and 100kg will normalise their athletic/cycling potential. If you are 50kg, you are returning a 2W/kg power and if you are 100kg, it's a 1W/kg power. Having this number helps to normalise two different level of effort and potential - and this at a competitive level will tells you just how ahead or behind you are against your target power output.
Professional cyclists may have anything 6W/kg onwards - as their numbers are often very closely guarded. A professional triathlete (Ironman distance) are known to hold above 3.5w/kg over 180km distance and can wrap the distance up in less than 4:30 - mind you, that is them being prudent with their energy as they have to run a 42km after.
If I have the W/kg of a pro-cyclist, I would be turning in 420W average power. In reality, I have something half of the pros - and that is nothing to be shy of.
Functional Threshold Power or FTP
This is the running Lactate Threshold (LT) equivalent on both pace and heart rate. Obtaining the FTP allows you to shape your training as a percentage of effort. Power meter will be able (and smart enough) to calculate these for you, as long as you put in the appropriate effort to get the representative data. Typically, it is measured in the average power you can generate in space of 20minutes at your best effort (you do want representative data no?).
Intensity Factor or IF
Likely the most useful data after your FTP as it determine to what workout you want to do, or did. It is a ratio of normalised power (NP, which usually differ by 1-2W to your average power) to your threshold power. You can think of it as percentage of effort compared to your maximum. Obviously, when you get stronger and clock higher FTP, your training effort too will change to match the same IF - for future or immediate improvement. Rule of thumb, anything between 0.85 and 0.95 is a good base for Tempo ride or coupled with both aerobic and anaerobic spin simulation to a less than 2.5hours ride.
Training Stress Score or TSS
I think of this as a "point collection" for my exercise as it measures as a function of intensity and duration of the workout. You score a TSS of 100 points if you can ride at 1.0IF for 60minutes. Similarly, an 1.0IF for 30mins gives you the same TSS as a 0.5IF for 60mins. How TSS aid in your performance? It's an indication of the work you did (performance) and how much rest you may require to recover.
Making Training Fun
With the basic knowledge of Power in cycling and usage of Power meter, you can then train within your efficient parameter. Couple this training with Heart Rate, you may just find the sweet spot where you can cruise at 60% HR effort while churning out strong enough IF to sustain a race throughout.
This will allow you to strategize and stick to your power output no matter what the race condition is. Imagine two triathletes cycling against a strong headwind, one continue to push at 35km/h at a higher power output he is not trained for, while the other play it smart by sticking to his training power against the headwind at a lower speed and keeping up the power with higher cadence, without burning out and have a lot more juice left in the tank to complete the race strongly. With this knowledge, I train between 0.85IF and 0.95IF.
At my current 254w FTP, that translate to a moderate (by cyclist standard) a 3.1w/kg power output. This will typically translate to 220W average power - and I aim to improve on my FTP while maintaining the IF. Let's try to get the W/kg to a sustained 3.5w/kg and above!
Or fun things you can do is to try to break some virtual record by doing a 1-minute sprint interval. Imagine if I can cycle as strong and as fast as above at the power and average speed - I be done with my 180km Ironman cyclign in 3 hours, including water stop. ;-)
This unit of Garmin Vector 2S is courtesy of AECO Technologies in collaboration with 2ndSkin Asia. Recommended Retail Pricing for the Vector 2S is RM3250 including GST. The Vector 2 (both left and right power capable) RRP for RM5800 including GST. Available (pre-order possible) from all Garmin authorized distributors nationwide.