Ok, folks....this is REALLY embarassing, but -

I cannot do a SINGLE situp - bent leg or straight leg, free-foot or trapped-foot.  I can't do a single v-sit or resisted roll-up.  I tried, today, and my lower abs let me know in NO uncertain terms that they didn't appreciate it! 

I can do a crunch to about the mid-back level and that's it - I can't get up any further.  I *can* do the suspended crunches and similar ab exercises, but I don't get a full ROM like is shown in the videos and I exhaust very quickly.  In the suspended pull-through, I can get my hips back to my arms, but no further.

Any recommendations to gain strength in my lower abs?

How about the bicycle crunch? Lay on your back with your legs straight; draw in one leg so the knee is as far up you can go, towards your chest; return the leg to straight and do the other leg.

 When doing a situp focus on a point on the ceiling/sky and keep looking up to keep your back straight and prevent your chin coming into your chest.

Can you get your upper body off the ground at all? If not you could try trapping your feet and then raising your upper body with a few pillows and see if it's easier from that head start. Then as you advanced you could lower your start position by removing a pillow, until you're back on the floor.

Running & jump rope are also good for core strength as they activate the abs to help you keep form.

MaxKon:

How about the bicycle crunch? Lay on your back with your legs straight; draw in one leg so the knee is as far up you can go, towards your chest; return the leg to straight and do the other leg.

That, I can do - I was able to do the hamstring curl and the supine bicycle, although I didn't have as full a range of motion as seen in the videos.

MaxKon:

 When doing a situp focus on a point on the ceiling/sky and keep looking up to keep your back straight and prevent your chin coming into your chest.

Can you get your upper body off the ground at all? If not you could try trapping your feet and then raising your upper body with a few pillows and see if it's easier from that head start. Then as you advanced you could lower your start position by removing a pillow, until you're back on the floor.

That may be possible - I'm able to crunch up to about mid-back but that's it.  I'll have to see if I can find anything suitable for a pad to elevate my back.

Would negatives be of any utility for this?  Start in the up position and lower myself to the down position?

MaxKon:

Running & jump rope are also good for core strength as they activate the abs to help you keep form.

I'm not in condition yet for running, but I *do* have a jump rope.  It doesn't take me any time at all to get to a high heart rate, though.  I went to an ~85% rate in one hundred jumps for my warmup yesterday.  (Max HR is 177, I was at 156 after the rope jumping and at 150 after finishing the whole workout).

 "Would negatives be of any utility for this?  Start in the up position and lower myself to the down position?"

I would think so. Negatives can often be a useful tool at getting past a sticking point. I'd try to do some partial reps before negatives. Negatives for some reason that is wonderfully biological out of my memory can cause soreness. Limit the amount you do, and don't do them too often (not more than three times a week).

 Do the planks, without the TRX if necessary. For those bicycle crunches, don't put your heels in the TRX. It sounds like you're really out of shape (been there), the best you can do is just persevere and keep at it.

Also if you find you are getting too much resistance, try adjusting your position so that you move towards the anchor point, not away from it. This could help a great dealwith situps.

xenophon: I don't think Mike is doing situps with the TRX, but your advice about adjusting position made me think od something I just tried, and i think it made the situps easier...

Move your knees apart so your legs are at a 30-45º angle from eachother.

I'm not 100% sure it actually made it easier, but it seemed to help, at least with the controled aspect, since i definately found it easier to avoid jerking.

Now the standard plank (face down) works your back, and the side planks work your sides (i know, shocked me too), so perhaps you could also do a reverse plank. Feet in the TRX with your back and legs in a straight line, with your butt off the floor. You can either have your shoulders on the floor or on a raised platform.

You can adapt the sit up by positioning your self with your feet closes to the TRX and your head furthest away and grasping on to the TRX handles. As you try to sit up off the ground, use the TRX to assist the action only as much as necessary. From the top try to lower down without assistance that will give you the negative training that has been mentioned previously.

An additional exercise that will help is the TRX leg raise and any of the suspended exercises. Have you been able to progress to them yet? If not let me know as there is a great way to do this efficiently.

Fraser:

You can adapt the sit up by positioning your self with your feet closes to the TRX and your head furthest away and grasping on to the TRX handles. As you try to sit up off the ground, use the TRX to assist the action only as much as necessary. From the top try to lower down without assistance that will give you the negative training that has been mentioned previously.

I hadn't thought of reversing it - I will give that a try.

Fraser:

An additional exercise that will help is the TRX leg raise and any of the suspended exercises. Have you been able to progress to them yet? If not let me know as there is a great way to do this efficiently.

I've done all the exercises in the Core Strength and ABX.  I've failed out on the V-sit and rollup exercises, I think due to muscular fatigue.  I've been able to sit up in bed, possibly due to the bit of give under my hips from the mattress, I'm unsure.  I can do at least one trapped-foot situp but cannot do a free-foot situp (just tried to see if I can do them at all).

I'm basically back to zero after not working out for the last couple weeks - a slipped disc in my back and travel back home to Texas for a funeral really put a crimp in my workout schedule.  I'm currently fighting off a cold and bronchitis (yay, travel) but hope to be able to re-start next week.

I had an idea for you just now. Do the ones you struggle with most at the very begining.

MaxKon:

I had an idea for you just now. Do the ones you struggle with most at the very begining.

That though had crossed my mind, too - thanks!!!  I also though about doing reverse situps or reverse crunches.

I'm still fighting off the cold/bronchitis - workouts are still on hold

I hope you recover soon.

Thanks - I'm slowly getting there.  Between the travel and the sudden cold snap over here in Kosovo, it's taking a bit longer than usual, unfortunately