I realize this thread is a few months old now, but I decided to see how things go hitting my heavy bags without wraps or gloves. Before testing this, I started regularly doing finger extension exercises with a resistance band (its like a thick rubber band) to help strengthen the tissues on the top of the hand. I felt comfortable testing this for several reasons: - Not going to Muay Thai classes right now, so if I injured myself I could just give it time to heal. - I built up slowly (more on that below), and paid very close attention to any soreness/discomfort I feel when striking. - I have been hitting with wraps & light bag gloves for a few years now, and can go full power in those for a long time with no discomfort (unless I mess up the form of the strike--I very occasionally don't tighten or line up the wrist properly and get a bit of wrist discomfort). - The volume of total strikes I throw in a week is fairly low--I've been doing 30-45 minute sessions maybe twice a week lately. I started with hitting fairly light, but progressed to moderate and even some full power strikes when that didn't seem to cause any issues (after perhaps 4 sessions where going light didn't seem to cause any issues). My thicker vinyl bag (water filled) does cause some very minor discomfort/soreness if I hit it with full power repeatedly. At first I would stop hitting it for the rest of the session if I noticed any soreness, but after a few sessions where my hands felt completely fine afterwards (tapping/pushing on the knuckles & other areas to see if they felt at all bruised/uncomfortable/etc), I would continue striking for a little bit, but not to the point where the soreness progressed further, just a few additional hard strikes. The bag manufacturer does say to never hit it without hand protection on. And its certainly thick enough that open hand strikes sting quite a bit, and I can't roundhouse it without severe stinging pain in the top of the foot (the bag is squishy due to water filled, so the top of the foot always ends up impacting the bag too, even if the initial impact is with the shin). It takes a good number more strikes on my leather (cloth stuffed) banana bag to get any discomfort, even at full power. I've since been doing all my sessions unwrapped with no issues. No discomfort at all after the session is over, and the minor soreness/discomfort on heavy strikes fades fairly fast during the session. On a scale of 1-5 (1 = touch contact only, 5 = full power), I usually start at a 2 or 3 and progress to mostly 3 & 4 during a session, with occasional bursts of full power punches. I do this on both the vinyl & the leather bags. I'm not sure whether doing this has long-term ramifications that I just am not feeling at all yet. I know I am putting myself at higher risk of injury (especially throwing strong strikes) than if I wrapped up. I've continued doing it unwrapped mainly because I haven't noticed any issues at all, and I figure it is beneficial toughening/conditioning. I think my current low volume of striking is about the limit for unwrapped though--I give my hands 2-4 days between sessions, and the sessions aren't particularly long. If I increase the volume of training, I'd wrap up & glove up for most of it, and keep unwrapped striking to a fairly low volume.