. >> reporter: noah neiman is the co-founder of rumble. as 60 people train at the same time. >> there is nothing like a boxer's high. it makes you feel like ali in his prime. >> reporter: he says 70% of his clients are within. >> i've learned technique and as i'm relaxed, i still feel invigorated and very, very powerful. >> reporter: two regulars at this studio are 24-year-old mariah strong and 1-year-old chase carter. both top models in new york city who say they use boxing regularly to stay in shape. >> time for my first class. after a quick warmup. >> right hand, thumb, turns down. >> reporter: it's time to hit the bag. half the room starts on strength training while the other boxes. >> hey, hey. >> reporter: noah says boxing works every part of the body. but legs are the foundation. every punch starts there. boxing is as much a mental workout as it is physical. according to clinical psychologist dr. vivian diller. >> women are invested in breaking boundaries and boxing has been up until now a male dominated sport. women want to push th

. >> reporter: noah neiman is the co-founder of rumble.ny as 60 people train at the same time. >> there's nothing like a boxer's high. it makes you feel like ali in his prime. >> reporter: he says 70% of his clients are women. >> i've learned technique, and as i'm relaxed, i still feel invigorated and very, very powerful. >> reporter: two regulars at this studio are 24-year-old maria, and 19-year-old chase carter. both top models in new york city who say they use boxing regularly to stay in shape. what most surprised you when you started boxing? >> the strength of my core got super strong and leaned out in the middle, kind of like an hourglass. >> and everybody wants that. >> what do you think about phrases like punch like a girl? >> if we could just prove them wrong, right? >> reporter: after a quick warm-up, it's time to hit the bag. half the room starts on strength training, while the other half boxes. noah says boxing works every part of the body, but legs are the foundation. every punch starts there. the last thing we worry about is t