Being someone who suffers from chronic low back pain, I feel it interesting to offer up this tidbit of info. Over the years I’ve done a few different things to help alleviate low back pain while riding, and a lot of the suggestions on here help immensely. The most helpful are like Maxswell mentioned, doing isometrics for your abdominal muscles while riding certainly helps and maintaining strong core muscles is key BUT, keep the rest on your back and neck muscles strong as well.
I’m 6’-1” and two of the best additions I made to my bike over the years that helped aid in the comfort of riding were a Sargent Seat and HeliBars. The HeliBars gave me a slightly more upright riding position and the seat forever changed the way I sit. The factory seat seemed to slope endlessly toward the tank causing discomfort, well you know where, down by area that contacts the seat. LOL. I‘d compare it to straddling a banana, and the narrower the seat the more Uhmmm pressure points, causing an increase in discomfort and an increased tendency to move around more on the seat to alleviate this pressure. This in turn caused an increase in low back pain and a viscious cycle of discomfort. The Sargent seat is shaped more like the saddle on a horse so instead of sitting “ON” the seat, it’s more like you sit “IN” the seat. Since the Sargent seat slopes a bit upward at the front it helps control movement on the seat that you may experience from sliding/rocking forward and back when you accelerate/decelerate. The mere fact that the seat removes some of the pressure points on the butt and inner thigh area, will help keep those muscles relaxed and prevent cramping/spasming of the low back muscles.
The HeliBars help relax my reach to the bars, and allow me to have a bit more of a bend in my elbows while riding. This aids in discomfort caused between the shoulder blades and the low back. I still noticed a bit more tension between my shoulders and would experience a bit of a knot, but nothing too terrible. Over the last few years, this knot seemed to becoming more prevalent so I tried, you guessed it, a new windscreen, to help reduce wind turbulence on my helmet. After trying about 3 different styles of screens, the one that worked best FOR ME, was an MRA Touring screen with the adjustable lip spoiler.
The final thing I have added to my bike that has made the biggest difference yet was a used set of Throttlemeister bar ends. Unfortunately no longer available the Throttlemesisters are type of throttle lock. One brand still available that is similar in design is the Kaoko Throttle lock by the way so you may want to consider those instead. They use friction to help prevent throttle hand fatigue by preventing the throttle from snapping shut when you let go of the throttle. The throttle can still be easily manipulated, even with the “lock” engaged. By being able to engage the lock while riding gave me the ability to release my grip a bit on the throttle without having to come to a stop, and as a result I could shake out my right arm, and my left. It’s hard to imagine how much stress your right hand is under until you release it while riding, and this can be especially true on longer rides. Because of the way the human body works, when your right arm gets sore and the muscles on that side of the body become sore, guess which side of your body usually hurts MORE. You guessed it, the OPPOSITE side, as that is the side of the body compensating to relieve stress on the other side.
in my particular case, all of the additions have made a positive effect on my level of comfort while riding, but this is very personal as what might work for me may not work for you. There are sooooooo many things that can affect the feel of a certain accessory.
Another issue in modern day society, that most all of us are guilty of, myself included, is spending far too long staring at our phones. You know what I mean, sitting in a chair with your phone in your hand, staring down with your head bent forward. This postural position is HORRIBLE for your neck and upper back muscles. Guess where you will feel the effects of this pain the most. When riding, you’re doing a little bit of the opposite by trying to hold your head up, using the muscles that have now been fatigued by staring down at your phone/tablet/computer screen.
The long and short of this whole long winded explanation is that any change you make to your bike may change an angle somewhere else, that may increase or decrease some level comfort elsewhere. So just be conscious of what each change does or may to your bikes ergonomics, and if you make a change pay conscious attention to whether it helps or hinders the level of comfort.
NOW, for GAWDS sake, if you’ve made to the end of this little rant, you’ve been spending far too long reading on your phone/tablet/computer so go stretch a bit and get out for a RIDE. YOU NEED THE RELEASE.