Cruzbike power surge using upper body

[alexul]

I also live in a valley and I can ride along it for 70-80 km with very little elevation. Or I can ride across the sides and as soon as I exit the house I have a 10 min climb at a constant 10% grade, then a eye watering descent with a top speed of 80km/h and then another hill and so on. In a short loop of 20km I can get like 600 meters elevation. I do not dare to take my recumbent on that one, I can't imagine pushing it up at 14.5 kg and also letting loose downhill where it would easily reach 100km/h. So due to my hip injury I rode the recumbent only in the valley but it was becoming so damn boring riding the same route every time.

Maybe the S40 would be indeed better at climbing but I don't understand how they advertise it for short people. I'm 170cm height, 5ft7, and tested a Bachetta with the same seat height, 61-62 cm, and I would barely scratch the floor with my toes. Stopping would mean leaning to one side but then the start was difficult as I was already unbalanced. The v20 has an ideal seat height but maybe too laid back for continous climbing.

 

[vosadrian]

For me, I am in a valley in a bowl in that I have to go up to get out of it in any direction. One direction goes towards more hills and the other goes towards a more flat area (relatively). To go in the flatter direction I still have a few 5 minute climbs to get over to get there, and even the flat area is more rolling hills. Rolling hills are pretty good for the V20. They are short enough that you can carry your momentum half way up the next climb so really only need to put in effort for < 1 minute to keep the momentum going over the hill.

Unfortunately it is just not possible for me to do a ride on flat roads near where I live. I purchased the V20 because it is claimed to be the best recumbent for hills, and I like my speed. I like setting PRs, and the V20 seems the best bent for doing that... and even getting a few KOMs on the right segments. I do really need to get some taller gearing to exploit that more on the rolling hills. Often I have to coast down them as I can't pedal past about 60-65kph.

 

[Bo6]

There has been research on this,

Effect of low recumbent angle on cycling performance, fatigue, and V˙O(2) kinetics - PubMed

Lowering the recumbent angle to 15° resulted in shorter performance, larger fatigue, and altered V˙O(2) kinetics.

pubmed.ncbi.nlm.nih.gov

There are other articles as well.

In a nutshell:-

The more laid back on your bike you are the lower your hydrostatic pressure is.

As a result of this the stroke volume of your heart goes up, this will lead to an increase in heart rate as you compensate for the reduction in hydrostatic pressure.

So when putting out an effort and getting up to your LTHR (lactate threshold heart rate), given your stroke volume is already higher on a recumbent than a DF this will impact your VO2 max and the max power you can put out.

There are other things as well, DF are lighter which makes a difference when going up a climb, more so when that climb is greater than 8% which is where weight of a bike plays a big part.

Thanks, interesting articles I would not have thought that the position made as much difference.

I understand the weight issues all too well, my 25lb DF is a slower climber than my 18 lb one and my 30lb MTB is the slowest. The Q 45 is the slowest of all and also the heaviest at 33+ lbs. Since DF are not an option any more I'll keep looking for a light more upright recumbent. Just waiting for spring to try out the Q45 on some local gravel logging roads. Now on to the trainer to build the recumbent muscles.

 

[David Saxton]

I'm interested in the pedal power numbers from a Cruzbike vs swapped to a Bacchetta or similarly sporty, stiff recumbent. I'm curious as the OP about what you can gain - the video of the upright bike rider clearly shows how a rider's hips move around like crazy when standing and pedaling. Hard to do that on a recumbent especially when you're very reclined. I'll stay tuned to this thread

Meanwhile, I don't own a Cruzbike (yet), but I did buy a used Bacchetta Giro a a few months ago that came w/ open cockpit handlebars and bar tape on the flat sections to either side of the stem. I'm still getting used to it and have been running the seat at about 40 degrees. I think that the tape's partly there to hide the cable housing and brake lines, but I've also found I can take my hands off the regular grips and lean forward to grab that section with both hands and get a sort of a standing pedal effect by raising my whole back off the seat (kinda like a rowing position) while pushing and pulling on the bars opposite to my feet.

As others have rightly pointed out, I don't think this really allows your body to do more work overall (your ability to move oxygen will be the limiting factor in a sustained effort) but I can definitely stay in a higher gear and muscle up a short climb this way. I don't have device for measuring power but I have a pretty good sense of when I'd need to downshift on one of my regular climbs and can avoid it but this sitting up and pulling on the bars motion. Just like standing up on a DF, I've observed that this pedaling style loads the knees up more intensely and so would require more strength training than I've put in to utilize it for very long.

I guess my point is that you may not actually need a MBB to get a burst of power on a recumbent if you have some other way of changing your body mechanics, though I do agree that involving the upper body in some way can feel nice when you're trying to mix it up on the climbs or quickly sprint over a hill without losing your momentum. I also agree that most RWD recumbents that are highly reclined probably don't off much opportunity for this sort of thing as your arms just aren't in a position to do that much.

Photo of my "standing" bar grip hand positions on the Bacchetta below:

 

[murmur]

@vosadrian wrote: On a DF when you are in a standing position, you tilt the bike over so the pedal you are pushing down on goes upwards against the downward push of the pedal. As a result the legs do not moves as far to complete the crank rotation. Some simple high school physics (W=Fs) will prove that you are using less energy in your legs to produce the same force over a shorter distance. You have moved some of the energy to the upper body (which levers the bike from side to side). it is less about the steering from side to side, and more about tilting the bike over.

On a cruzbike, you' don't tilt the bike like a DF... but you are pushing the pedals out rather than down due to reclined position, so I guess moving the steering from side to side could have similar effect?

This is the answer; When the crank (or rather the extension of the crank's axis out to the pedal's lateral location) moves toward the hip joint during the power stroke, with the force provided by the leg being unchanged (as when the crank wasn't moving toward the hip) then the leg is providing less power. If the achieved (overall) power is the same, the difference is made up by "non-leg" sources. So to extract power from non-leg sources (a good thing if your legs are getting tired) on a Cruzbike, make sure you rotate the front wheel to the right *during* the right leg's power stroke, and rotate the wheel to the left during the left leg's power stroke.

The above idea about how Cruzbikes extract power from non-leg sources is why I don't quite understand why @LarryOz said this works on a trainer. You don't have a trainer that allows the front wheel to steer, do you Larry?

 

[LarryOz]

The above idea about how Cruzbikes extract power from non-leg sources is why I don't quite understand why @LarryOz said this works on a trainer. You don't have a trainer that allows the front wheel to steer, do you Larry?

I am not sure of all the facets to it, but if you lean forward a some and grab a hold of the drops and alternate pulling on each one - in a back and forth motion - you will see you power increase on the smart trainer. Obvioulsy the front wheel and cranks are not moving side to side. Maybe it is a placebo effect? Maybe using the upper body in this way and it is just engaging some different legs muscles while you are pulled up.
Hoping @Jim Parker can chime in as he has actual test results and measurement if memory serves me correctly.