Pedaleur

I think it's easier to stop here and say that for one-legged weights, you should divide this by two. Each leg does 140J of work per stroke. Then, following WR's analysis, for a 0.35m extension (one leg stroke -- no need to use 0.7m and then divide by 2 later), the force needed is:

F=140J/0.35m=400N

This is the force you want on each leg, but you have to take in to account the angle of the sled (as WR did) to get the weight, W, that you want to lift:

W=F/cos(sled angle)=400N/0.707=566N=~58kg=~127lbs.

The final answer doesn't change (as noted in the follow up for one leg), but I think it's a little clearer this way. No dividing by the pesky 2.

It should be clear that this is at 0.8 sec/interval, which includes both a 0.4 second extension and 0.4 seconds of rest, since we're only talking one leg. Obviously, you can't let the weight drop freely, so there will be some extra work done while you let the weights down.

From here you just realize that power=cadence*(work/rep) and you can adjust for different power levels or cadences.

Pedaleur

Nice. But you should put "divide the weight by 2 for one legged reps" on there.

waterrockets 

Good points, done.

waterrockets 

Dude, I'll bet you can understand the spreadsheet...

NomadVW 

So if I understand the point of the spreadsheet correctly...

If I want to replicate the force required to pedal @ 360 watts, 95 RPMs, on 175mm cranks, I can do leg presses on a 45° sled with 206lbs - which doesn't account for any negligible pull motion of the pedal stroke

or....

I can go get on my bike and spin 95rpms @ 360 watts, which happens to incorporate the whole pedal stroke at the same time?

I think I must be missing something.

waterrockets 

Nope. You got it -- I was wondering when someone would bring that up

I'm just here to help with the math

EDIT: actually, this could be useful for sprint and AWC training, if you didn't want to just do it on the bike. Predicting your 30s power, setting up the weights and getting after it would be cool. See if you can get 50 reps in before 30s is up...

You could also double the weight and cut the rate to make it more manageable. For me, at 821W for 60s would be 477 lbs at 95rpm. The weight would be coasting over the top, so slowing it down to 47rpm at 954 lbs seems so much more manageable over a 60s set.

Jynx

Keep your units consistent. It kills me to see lbs, kg's, inches, mm's, joules, watts, lb-ft, lb-in, ect all in one problem. Thanks USA.

Nbois

+1

Do high reps with low weight, slowly work the weights up and feel the burn.

Pulling out spreadsheets and calculators at the gym is as fred as a helmet mirror in a crit.

waterrockets 

Yeah, it really is ridiculous in the US. We start off MKS on the bike, but the leg press is likely to have English weights racked up next to it. Easier to let the spreadsheet do the N->lbs conversion for you. Inches makes more sense for rep distance to most Americans, so I converted that too.

ridethecliche

I'd like to a see a spreadsheet of sorts.

I think I'm going to hit the weights a bit this week so my body doesn't die of soreness if I do it too late into the winter.

Edit: I can't see doing high reps at a cadence like speed on a weight machine being good for your knees due to the abrupt change in directionality.

Hocam

My mistake, I used miles to km conversion which is 1.61, you're right it should be 176 lbs.

Hocam

If you pedaled with the same torque all the way around than you would be right, but it isn't that simple.

I think the power correlation is both more accurate and easier to simplify.

waterrockets 

Yeah, that's why I'm thinking it might be better to double the weight and halve the cadence. Same energy to turn it around, but lower speed.

Enthalpic

You’ve distorted the question. The question was how to mimic the force demands of the TT, not the power demands. Both fast-light reps and slow-heavy reps will put out the same amount of power, but with drastically different adaptations / metabolic demands.

I highly doubt DrWJ is trying to work at FTP while weight training –he certainly won’t be trying to do hour long sets. One of the potential advantages of weight lifting is that force and power can be adjusted fairly independently. He can expose his muscles to the maximal amount of strain they will encounter racing while working at alternate power levels. I doubt DrWJ can hit his goal FTP right now, but he can train at and above his goal force.

How does your model handle the situation of holding the optimal weight stationary at the 3 o’clock position?

Of course you can adjust the force demand for a given power output while riding by changing gears, but it is much more difficult to control precisely.

waterrockets 

Yeah, I'm not a fan of weightlifting anyway, but if I were, I'd be doing 15s, 30s, and 1m sets.

I still think the sheet is a reasonable way to evaluate how much weight to do.

I'm not sure what you mean by "stationary at the 3 o'clock position"

Flatballer

Did I see that WR is saying he should be able to press almost 1000 lbs 50 times in a minute?

I'm never gonna be a racer...

Enthalpic

Lower the weight halfway and hold it still. Muscle tension without "work."

waterrockets 

I dunno. It would be interesting to take some of this to the gym. My gym at work just has cable crap, so all this is out the window for testing.

Back in the day, I was over 1250 lbs 10x, and that was pushing a lot further than 14". It was also a 3rd set. I think 1000x50 at 14" would be a maximal effort if possible at all, but not unreasonable.

Don't base your ability to win races on anyone else's abilities. There are lots of ways to suppress someone's 1m power in a race

True, and there's also the lowering and deceleration of the weight at the bottom.

NomadVW 

Pump, spokes.

patentcad

I can't understand my remote control.

DrWJODonnell

Thank you everyone for your help and input. I knew that someone would bring up the following, so to quote Nomad...

I will try to explain, but it basically has to do with winter burnout being a very real and easy thing for me living in the northeast. In the northeast, we do not have a lot of good riding days in the winter, and so cycling specific gym work is really helpful both mentally and physically. I am not trying to raise threshold, but prepare the muscles for slogging through eventual 20 minute sets of continual force (both positive and negative) on the muscles (spinning gives each leg a "break" for half of a pedalstroke. You are pretty much only doing concentric contraction and thus don't get the benefit of eccentric contraction that occurs with weights). In addition, while closed chain, the weightlifting should help to strengthen muscles, tendons and ligaments "generally" without the motion being restricted to the circular pedal motion which can cause injury when dealing with heavier torques. I will get strength/anatomical changes, but without locking in the joints to the uber-closed and potentially damaging constraints of the pedal motion. Plus, it helps general fitness and becomes weightbearing exercise giving the bones and joints much needed work as well.

I hope to get a great workout that would be the equivalent of a quadrant II focus in about half of the time that would be required on the bike and will supplement bike workouts and while helping stave off 7 days/week of indoor riding for several hours on a trainer. The idea of having resistance both concentric and eccentric is going to be the key. If I can develop the ability to continually handle a certain level of contraction (say 15% higher than what I will experience on the bike at threshold wattage) through the full range of muscular movement, without rest, I feel (and have felt in the past) that this will assist me in my cycling ( I always use weights in the offseason, and often paritally in-season). I am just trying to fine tune that so that I can look to past TT performances and create that target weight, without overshooting it into the realm of absurdity which is very easy to do with weights.

Thus the query.

Does that make sense as to why I would want to have a weight workout rather than a cycling workout?

ridethecliche

Yessir!

I'm considering the same thing myself.

When the weather gets much worse, more trainer and gym time. I can only ride at 8-9 am on tuesdays and thursday, and then saturday and sunday mornings. This means that I'm going to be riding when it's the coldest in the morning pretty much. I would much rather not do this if possible, so I'm probably going to ride outside 1-2x a week to do some workouts and hill repeats without straying too far from home (changing a flat in the cold can be a huge PITA), and then do the rest of my workouts in the gym or on the trainer.

Since I wasn't active for a while this summer due to injury, I want to do some full body weights (low weight high rep) to build all around strength to make sure I start the season with a strong core and strong legs.

I might end up going out more often than I'd want to since I did just get an SRM and I really want to play with it Either way, 1-2x a week outside will end the monotony of trainers (2x a week) and gym (2x a week), and I'll be much stronger and will feel much stronger in the spring.

I'm psyched for 2009!

fuzzthebee

I have a PT Cycleops bike in addition to my PT on my road bike. One cool thing about it is you can ride any cadence/power combination, just by manipulating the resistance dial. If I want to do 300 watts @ 50 rpm, no problem.

I can set it to "torque mode" which claims to display inch-lbs, but the numbers I'm seeing during the ride don't correspond to what I get in Cycling Peaks after I download my rides.

For example if I ride at 350 w and 90 rpm, CP shows an average crank torque of 37.2 N-m, but on the bike it's reading ~90 inch-lbs. From what I've read here, 37.2 N-m would equal ~327 inch-lbs. What's the deal?

Hocam

1.8 Kilo-Newton meter = pound inch

You only multiply by 10 (really 9.81) when converting mass to weight in the metric system.