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View Full Version : substitutions: 1) for back extensions 2) equivalents of double unders


Jeff Yan
11-26-2008, 09:18 AM
Posted this on another board, but didn't really get my question answered.

1) How much weight should your barbell be if you substitute good mornings for back extensions (65#, 75#, other)?

I've used 1.5 pood KB before as well. Is this appropriate?


2) I realize this isn't a great substitution, but how many double-unders would you consider to be the equivalent of a 400m run or 500m row?

I think I run 400m in about 1:15-1:20 and I row 500m in 1:45-1:55. Last night I got about 41-42 DUs doing minute intervals while relatively fresh. I'm thinking maybe anywhere between 50-75 would be a reasonable range. 60 or 65 might be appropriate for myself personally given that I'm not a particularly good double-underer. What number would you choose for yourself?

Steven Low
11-26-2008, 09:58 AM
1. I'd start with just the bar (45#) and work your way up. Don't wanna get too heavy with good mornings if you're gonna be doing A LOT of them. Back/hip extensions aren't that much weight (just bodyweight) anyway.

2. Knee-to-chest tuck jumps is preferable sub for DUs (burns you out as fast as 400m run or 500m row too). Otherwise, depends how efficient you are with your DUs. 1 per second or thereabouts looks to be at your skill level....

Really though a lot of these questions depend on your ability. I dunno if you're doing CF or whatever but if something's too easy or too hard then scale up or down accordingly.

Garrett Smith
11-26-2008, 10:40 AM
I would think a little less than 1/2 BW on the good mornings would be plenty.

I'd rather do tuck jumps than double unders, personally. I never spent the time to learn DUs, nor did I see any tangible athletic benefit/transferability to learning how to spin a jump rope twice as fast as I could jump.

To answer your question more directly, I think 50 would be a great starting point.

[EDIT] Steve, it's funny, I didn't see your post until after completing mine...

Jeff Yan
11-26-2008, 10:51 AM
1) I used to think that an empty bar would suffice as a sub, since for a CF WOD we do back extensions for metcon, not for maximal strength. However, at my affiliate I remember doing a sub with a lightly loaded bar (hence the 65#/75# I mentioned earlier). I was wondering if there was a "generally accepted" weight loading in this case.

And I was actually surprised that the loaded bar for good mornings, albeit light, was relatively mild and quite manageable for higher reps.



2) In case there's any confusion, I was asking how many DUs to do in lieu of running or rowing, not so much what can one do instead of DUs.

But this brings up another question. What's the conversion rate of DUs and tuck jumps?

And Steven, if you're suggesting about 100 tuck jumps (~1 per second), while 400m runs and 500m rows aren't exactly a walk in the park (figuratively and literally), that many tuck jumps performed at once at high intensity sound absolutely brutally vomit-inducing.

Garrett Smith
11-26-2008, 11:51 AM
I used to sub KB SLDLs for back extensions, I think I used the 53#. That was plenty for me at the time.

If I still did CF, I'd now do 1/2 of the rx'd Back Extensions as reverse hypers (no weight added) and the other half as hip/back extensions with excellent form. I'd probably also be halving the rx'd amount off the bat to avoid overtraining and maintain form, but that's just me.

Jeff, you did get answers to the question you asked (# of DUs to substitute) and one you didn't (Steve and I both think that tuck jumps are a preferable exercise).

How to sub from the CF FAQ (I'm assuming you want these subs for CF WODs, so let's ask the experts on CF):
3.2. How does running compare to rowing, biking, etc.?
To compare the different aerobic exercises, pick a comparable time interval. For example, if you run 400m in 90 seconds, then row or bike or jump rope or run stairs etc. for 90 seconds.

3.3. What's a good substitute for running?
See previous for some suggestions. Also, box jumps, cross-country skiing, heavy bag work, kettlebell or dumbbell swings, weighted stair-climbing or box-stepping.

3.6. What if I don't have a rowing machine?
Do Sumo Deadlift High Pulls (see exercise page for demo):
If you don't have a rower substitute sumo-dealift high pulls (sdhp) with 45 pounds for men and 30 pounds for women. Take the bar from mid shin to under your chin--"shin to chin."
2K row = 200 sdhp's, 1K row = 100 sdhp's, 500 meter row = 50 sdhp's

3.12. I can't do double-unders, or I don't have a jumprope.
Do tuck jumps. Multiple single-unders in no way compensate for the exertion required for double-unders. Stand with your feet slightly inside the width of your shoulders. Bend your knees and lower your body down 8-12 inches. Explode into the air and bring your knees up to your chest in a tucked position. Upon landing, your feet should be in a strong, dorsi flexed or "toes up" position. Use your whole foot to generate power, not just your toes! Maintain good posture in your upper body. Keep your chest and head up. Don't let your shoulders lean out beyond your knees. This can stress your lower back. Explode off the ground as quickly as possible and repeat for the required number of repetitions.
Lessons:
1) Sub an exercise or number of repetitions that lasts about the same length of time.
2) CF has their own suggested substitute(s) for running, of which DUs are not listed.
3) CF has their own suggested substitute for rowing, SDHPs.
3) Tuck jumps are a CF-(and Garrett- and Steven-)approved substitute for DUs

To me, this would mean the best way to work in DUs (if you were insisting on using them, which would be fine by me) would be to pick a time interval and have the time intervals determine the length of your DU segment. Improvements in "fitness" (work capacity and coordination/agility) on the same workout scheme in the future could then be judged by an improvement in # of DUs completed in the set timeframe. Note that this may require two watches--one to time the entire workout, and one to time the DU intervals.

Hope that helps!