This is because although rowing is mainly about training your back, you still have to hold the handle with your hands all the time, and the dominant muscle here is your forearm. There are few forearm muscles, which are not as powerful as the large muscle groups in nature and are easy to fatigue.

The professional practice is to buy a pair of grip bands, which can help the handle and thus liberate the forearm from the exercise process. Another advantage of using grip band is that it can increase the effect of back training. For example, if you pull a weight of 100KG, the muscles involved will distribute their strength equally according to their own strength. After you use the grip band, your forearm will not exert more force, so the corresponding back will exert more force. I don't know.

If you don't know the grip belt, you can search online.