I just started riding after a winter hiatus, on my fourth ride I did 70mi. of rolling hills and after 55mi. I began to experience a tightening of my lower back muscles. I toughed it out and completed the ride, but as soon as I got off the bike I felt lower back spasms.

I researched on back pain and cycling and found that there sometimes is a relation between riding position and back pain, also saw that strengthening your abdominal core will reduce load on lower back.
Those of you who have experienced lower back pain, what were the main causes? How did you alleviate it? Should I feel discomfort and pain after 70mi? Due to road cyclings wind resistant positioning is some back pain expected?

I have to say that I pushed myself very hard on this ride (HTFU) or whatever. I almost vomited twice, but kept pushing. This is my 4th ride within the first week back on the bike, is it possible that I over exerted myself to early?

Yes.

That would definitely happen to me if I did a 70 miler after a long hiatus.

Stopping every 20 miles to stretch is a good idea. Working on your core is a good idea. Re-evaluating your fit may also be a good idea. If you did well through mile 55 you may wish to keep your rides 50ish miles for a while.

Good luck!

You over exerted too quickly on your way back. Take a couple of days off then get back to work. This happens to me occasionally, I wouldn't push through it, it just makes it worse. A few days rest usually does it for me. Good luck.

Too many miles too soon would be my diagnosis but, I'm not a MD.

I may have rode to much to soon.
The lower back muscles will strengthen to the load/stress of the position with time. Obviously if my fit is the problem it needs to be addressed, I will head to LBS where I bought the bike and have them help me out, however I just wanted to know someone's opinion on the effects of a strong abdominal core on cycling in general.

If you put a few pounds on over the winter, your back may have shifted slightly. Now you're trying to put it back into your old riding position. Because the pain came at the end of the ride, I'd keep on riding, but watch for signs of continued pain. If it decreases, it's just a matter of getting in shape. If it continues, time to see a orthopeadic doc.

now feel better:
- long hot baths with epsom salt in deep water (20 min minimum) with 3 cups of salt
- if your gym has a whirlpool - use it
- massage the area thoroughly with a mechanical device or a strong friend. mine has a long handle and two bulbs that I can move to the exact spots that needs the massage. sometimes it can be a little painfull but afterwards the area feels amazing.
- you can also most likely rub the area yourself
- if you go into complete spasm you'll need muscle relaxers - a kind of salt pill. these always piss me off cuz it takes a while to get back up to speed after the muscle spasms go away. this can sometimes take days for me. in a pinch you can use some Tylenol PM but don't expect to go biking.

remember rule #1 ~ do no harm

For me, a six pack of Guinness Extra Stout and a 1/2 hour on my inversion table does the trick.

I find some pre and post ride stretching helps.

https://www.bikeradar.com/fitness/art...our-back-24568

beer and inversion? that would make me throw up

Stretch out those hamstrings.

My back pain started ~7 years ago and it was slowly getting worse and worse until a year and a half ago it got to the point that i could not move at all, was driven to a doctor and ended up getting a cortisone injection. My doctor told me then that stretching is the best cure. Been stretching since then and so far so good - it never goes completely away but at least I am functional. All it takes is 10 minutes a day.

2-3 beers before inverting and the rest after. Also, I never fully invert- it's bad on the knees.

Sit ups. Lotsa situp and crunches. Take some Pilates courses.

Advice from someone who needs to take their own advice.

Do you warm up before you stretch? Is it a real gentle stretch or more of a vigorous stretch?

that reminds me, I have some rum in the freezer.

Sit ups are known to be hard on your back.

I do not warm up before that, I do a back specific exercises, such as Flying Superman, Spine Twist, bend forward and so on, 2 sets each, hold 45 seconds, rest 15. It is a gentle stretch. Give it a try!

all this is good but he needs to recover right now

Excellent sore back recovery drink:Captain Morgan Private Stock(3ounces)+ full glass of water.
Throw the glass of water in your face and down the shot of rum.Repeat as necessary.

Severe and sharp pain? Yeah, sounds like you did too much, too soon, too hard.

In answer to your question, here is my experience. I used to have a fair amount of back pain as a mountain biker, and it continued later when I switched to the road. And I used to believe, as many riders told me, that it just goes with the territory.

I believed it until I started strengthening my core. Within a few months of very regular exercise and stretching, my severe back pain was greatly diminished and for the most part, just vanished. The only real issue I've had since is if I neglect the workout routine for even a brief length of time. Once you start, you have to stay with it.

These days, after a really intense effort, I may notice a bit of pain, but it's pretty minor and disappears quickly on recovery. It seems quite acceptable to me.

As an added benefit, it seems I can climb stronger and sprint harder, as well as be much more comfortable in the drops.

Of course, there are other issues you can consider. Poor bike fit, bad form, or poor technique, STRESS, unfortunate genes, etc. And there's the Captain Morgan remedy you might want to consider.

"unfortunate genes"?
just kick the guy in the nutz why don't ya

Appreciate all the great responses, Thanks BF. I will definitely stretch pre/post rides now, I am pretty confident I have a good fit, the BG fit thing.
This isn't the first time I've started out too much too soon, e.g. Ran 8mi. and tore groin, had nasty bruised going the left of my groin. I will take it easier and if I have to I will stop and rest.

All else fails, I can always carry some Cpt. Morgan's and a fistful of soma.

Appreciate all the great responses, Thanks BF. I will definitely stretch pre/post rides now, I am pretty confident I have a good fit, the BG fit thing.
This isn't the first time I've started out too much too soon, e.g. Ran 8mi. and tore groin, had nasty bruised going the left of my groin. I will take it easier and if I have to I will stop and rest.

All else fails, I can always carry some Cpt. Morgan's and a fistful of soma.