Unfortunately, many of us are still not on the water. While there are other ways to stay in shape, rowing is a technical sport that makes it very hard to improve when not able to actually row. One of the few options available is visualization.
One of my favorite Olympic stories relates to just this. Laura Wilkinson was a diver training for the Olympic Trials in 2000 when she fractured her foot just five months before the Olympics and only a few months before the trials. Her foot was put into a boot cast for several weeks, meaning no diving at all.
She could have given up, but instead turned to visualization. Laura would spend hours watching video and then imagine doing each dive in her repertoire perfectly. She would actually climb the 10-meter platform, taking her 10 to 15 minutes to get to the top and stand there while going through each dive in her mind. When the boot came off, it still wasn't strong enough for her to dive so she practiced her dives underwater and on a trampoline.
By the time of the Olympics, Laura's injury was not yet fully healed and she needed to wear a shoe in order to climb the 10-meter tower. Her foot was also not strong enough to handle running and jumping off the platform, so she compensated by starting several dives from a hand stand position, unprecedented at the time.
China was the heavy favorite, having won gold in the previous 4 Olympics. Laura was in eighth place after the first of her final five dives but she kept climbing up the leaderboard, ultimately clinching the gold medal with her final dive, the same dive during which she had injured herself 5 months earlier. This was the first US Olympic gold medal in women's platform diving since 1964.
One of the most epic 1x races ever
I realize rowing and diving are very different, but they are both technical sports. In diving it's often how well you can hold up under the mental pressure, and in rowing how well can you hold up under the physical and mental pressure. Does your stroke fall apart when you get tired? When the water gets rough?
Right now, many of us are forced off the water so we need to find another way to move forward. Find video of a successful rower whose style you admire, break it down and figure out what it is you like and what helps makes them successful, be as specific as possible. (Some of these elements you may well be able to practice on an erg.)
Visualize yourself rowing this way, even when you're tired or when the water is rough. Visualization is like any other activity, you probably won't do it well at first, but keep practicing and you'll get better.
The body can achieve what the mind believes.
The body can achieve what the mind believes